A microvia is a small hole drilled into a PCB that connects different layers. They are essential for high-density interconnections and are commonly used in advanced electronic designs. Typically, microvias equal to or less than 150 microns drilled on the PCB board with a laser. In 2013, the IPC standard changed the definition of microvias to those with an aspect ratio of 1:1. Ratio of aperture to depth (not exceeding 0.25mm). Previously, micropores were less than or equal to 0.15 mm in diameter, so they typically spanned only one layer.
Because the diameter is very small compared to mechanically drilled through holes (PTH), we define them as microvias, usually connecting only one layer of the board to its adjacent layers. These through holes reduce the possibility of any type of manufacturing defect because they are laser drilled, thus reducing the possibility of any residue remaining after the process. Because of their small size and ability to connect one layer to the next, they can make dense printed circuit boards with more complex designs.
Types of Microvias
There are two types of microvias in the PCB design – stacked microvias and staggered microvias.
Stacked Microvias
Stacked microvias are formed by stacking multiple layers on top of each other to provide a path through which current flows. Create a hole in one layer and drill into another layer below. The top layer is welded or welded to the bottom layer to form an interconnect between the two layers. This allows for fast, efficient routing without compromising performance or reliability.
Staggered Microvias
The interlaced microvias is aligned with the pad of the same layer, but is offset from its center by half of the pad diameter. The distance from its center to the edge of the board is also half the diameter of the pad. Staggered microvias allow you to place two through holes in a single pad without overlapping them or having to route wires on different layers together in this location. This type of microvias can be used for electrical connections to the surrounding brass pads and traces.
What is the Difference Between Vias and Microvias?
Vias and microvias serve similar purposes in connecting different layers of a PCB, but they differ significantly in size and application.
1. Size
One of the most significant differences between vias and microvias is their size. Standard vias typically have a diameter greater than 150 micrometers (μm), while microvias are defined as having a diameter of 150 μm or less.
2. Design Complexity
As technology advances, the demand for higher circuit densities and more complex designs has grown. Microvias enable designers to create intricate multilayer circuits that were not possible with standard vias.
3. Layer Connection
Standard vias can connect any number of layers in a PCB, typically running from the outer layer through to the inner layers. In contrast, microvias are usually used for connecting one or two layers. Microvias are commonly employed in multilayer PCBs, where they can connect the outer layer to one or more inner layers without passing through the entire board.
4. Aspect Ratio
The aspect ratio, which is the ratio of the depth of a via to its diameter, is another important difference. Standard vias generally have lower aspect ratios, making them easier to fabricate. Microvias, due to their smaller size, often have higher aspect ratios. A typical aspect ratio for microvias ranges from 1:1 to 2:1.
5. Applications
Standard vias are commonly used in traditional PCB designs for applications where space is not as critical. They are suitable for general-purpose circuits, power distribution, and less complex layouts. In contrast, microvias are essential in high-density applications, such as smartphones, tablets, and advanced computing devices, where compact designs are necessary.
Microvias vs. Blind Via
Blind vias connect the outer layer of the PCB to one or more inner layers without penetrating the entire board. As the name suggests, these through-holes are “blind holes” because they are not visible from the other side of the PCB. Blind holes have several advantages, such as saving space on the board, enabling a more compact design, and improving signal integrity by reducing the length of the signal path.
The blind via passes through the surface layer of the PCB, extending through only a portion of the board to connect the surface layer to one or more inner layers. They are a key component in current PCB designs, allowing surface components to connect to inner layers while minimizing the number of layers required for wiring. The advantages of using blind vias including:
Increased density
Reduce the number of layers
Improved signal performance
Good for heat dissipation
Improve mechanical strength
Can Microvias be Designed in Multilayer MCPCB?
Yes, microvias can indeed be designed in multilayer MCPCBs. In fact, their small size and efficient design make them ideal for these types of boards. Multilayer MCPCBs often require compact interconnections to accommodate various functionalities, and microvias facilitate this need. By enabling multiple layers to connect efficiently, microvias enhance the overall performance of the MCPCB. Additionally, they contribute to improved thermal management, a critical factor in high-power applications. Their integration in multilayer designs is a significant advantage for modern electronics.
The process for using microvias in multilayer metal-based circuit boards includes the following key steps:
1. Inner laser drilling and plating: This is the first step in the production of microvias, precisely drilled by laser technology, and electroplated.
2. Resin filled: The micro-vias after electroplating are filled with resin to enhance the stability of the structure.
3. Resin grinding: Grind the orifice after the jack hole to ensure a smooth surface.
4. Electroplating: Metallize the surface of the orifice resin to achieve electrical interconnection between layers.
5. Inner circuit etching and outer layer lamination: To complete the production of the inner circuit, and the outer layer of laser drilling and graphic plating, and finally realize the production of multi-layer circuit board.
MCPCB Material in Best Technology
MCPCB Prototype Lead Time (Vary Depends on the MCPCB Design)
Designing and developing printed circuit boards (PCBs) may sound complex, but it’s an exciting process that is within reach, even for beginners. With the right approach, software tools, and an understanding of the basic principles, you can create functional and efficient PCBs.
Is PCB Design Difficult?
The difficulty of PCB design depends on the learning objectives and depth. ‌ If it is just the initial stage, do some simple circuit board design, then it is relatively easy. But if you want to go deep and get to expert level, in areas as diverse as pcb layout, signal integrity, electromagnetic compatibility, impedance design, and more, then you need to put in more work.
For beginners, choosing the right software and learning resources is very important. PADS from Protel, Altium Designer (AD) and Mentor Graphics are commonly used PCB design software. Protel software is simple and easy to learn, suitable for beginners to use; AD and PADS are powerful, but the operation is complex, suitable for the design of complex circuit boards.
What is the Basic Rule of PCB Design?
The key to good PCB design is layout organization. Keep the design simple, especially at the beginning. Here are a few basic rules to follow:
Control Trace Length
Controlling the length of traces means adhering to the rule of keeping traces as short as possible in PCB design to avoid unnecessary interference caused by long traces. This is especially crucial for important signal lines, such as clock signal traces, which should be placed very close to the oscillator. When driving multiple devices, the network should be determined based on specific circumstances.
Avoid Forming Self-Inductive Loops
In PCB design, it is important to pay attention to signal lines forming self-inductive loops between different layers, particularly in multilayer boards. The chances of forming self-inductive loops increase when routing signal lines between layers, and these loops can cause radiated interference.
Minimize Ground Loop Principle
The principle of minimizing ground loops is to keep the signal lines and their loops as small as possible. The smaller the loop area, the less external radiation and interference it experiences. When defining ground planes, consider the distribution of the ground plane and important signal lines to prevent issues caused by ground plane cuts.
In double-layer board designs, while leaving sufficient space for the power supply, the remaining areas should be filled with reference ground and include some necessary vias to effectively connect signals on both sides. Ground isolation should be used for key signals. For designs with higher frequencies, special attention should be paid to the signal loop problems of the ground plane, and multilayer boards are recommended.
High-Speed Signal Shielding Design
The relevant ground loop rules are also aimed at minimizing signal loop areas and are mainly used for important signals such as clock and synchronous signals. For particularly important and high-frequency signals, consider using a shielded structure design with copper coaxial cables. This means isolating the line from the ground on all sides while effectively grounding the shield layer and ensuring its connection with the ground plane.
Avoid the “Antenna Effect”
Generally, routing with one end suspended is not allowed to avoid the “antenna effect,” which reduces unnecessary interference radiation and reception; otherwise, it may lead to unpredictable results.
Chamfer Rule
PCB design should avoid sharp corners and right angles to prevent unnecessary radiation and poor manufacturing performance. The angle between all traces should be ≥135°.
Avoid Overlapping Different Power Layers
Different power layers should be spatially separated to reduce interference between them, especially between power supplies with significant voltage differences. Issues arising from overlapping power planes must be avoided, and if unavoidable, consider using an isolated ground layer.
Avoid Via Proximity to SMT Pads
If vias are not covered with a solder plug, they can easily be placed too close to SMT pads during layout. This can cause solder to flow through the via to the other side of the PCB during reflow, resulting in insufficient solder on the SMT pads and causing issues like cold solder joints. It is generally recommended to maintain a distance of more than 25 mils from the edge of the via to the SMT pad and to apply solder mask over the via.
Do Not Route Traces Wider than SMT Pads Directly into the Pads
If traces are wider than the pads, the window area of the SMT pads generally expands beyond the pad size. This means that if the solder paste on the pad is slightly insufficient during reflow, there is a risk of cold solder joints. Using traces that are slightly larger or slightly smaller than the pads can also help avoid excessive heat dissipation during soldering.
Do Not Place Components Too Close to the Board Edge
During the assembly and soldering stages of the PCB, the board will be transported through various processing areas, such as solder paste application and pick-and-place machines, followed by reflow soldering. Therefore, when designing the PCB, at least one side must leave enough space for a processing margin of at least 3 mm in width and 50 mm in length. There should be no interference between components and leads within the processing margin, as this could affect the normal transport of the PCB.
If the layout cannot accommodate this, consider adding an independent 3 mm processing margin or panel. (Note: SMT components cannot be placed within 5 mm of the edge on either side of the processing panel to facilitate reflow soldering.) If the components on your PCB are hand-soldered, you can disregard this requirement.
Keep Solder Mask Window Sizes Consistent
The solder mask layer needs openings for the pads. These openings prevent the solder mask from covering the pad area, protecting the PCB circuit from oxidation and short circuits during soldering. Typically, a solder mask layer covers the outer layers of the PCB. Common solder masks are green (though black, red, yellow, and blue are also used).
Solder should not be applied to pads to avoid solder paste sticking. To avoid the solder mask layer interfering with pad solderability due to process tolerances, it is common to design a solder mask opening that is larger than the pad by approximately 0.1 mm (4 mil). However, it is also acceptable to keep the solder mask opening area the same size as the pad dimensions; the factory will process it uniformly for you.
Reduce EMI Interference
Every PCB can be affected by EMI or become a source of interference. As part of the engineering design, special attention is required during PCB layout:
Increase the spacing between high-frequency traces and low-frequency or analog traces.
Minimize the return path for high-speed signals and ensure they do not cross split planes. Smaller current loops reduce EMI radiation intensity.
High-speed differential signals should be routed in parallel and have equal lengths; otherwise, they will offset the noise suppression characteristics of the differential pair.
Avoid using vias on high-speed traces, as they may lead to EMI emissions.
What Files Are Needed to Manufacture a PCB?
When you’re ready to manufacture your PCB, you will need to generate specific files for the fabrication process. The most common file format used by PCB manufacturers is the Gerber file. Here are some other important files that needed to submitted to manufacturer:
1. Gerber Files – your design files, include the design layout, detailing copper layers, solder masks, and silkscreen layers.
2. Drill Files – specify the locations and sizes of holes for vias and component leads.
3. Bill of Materials (BOM) – a list of all components required for the board, including part numbers and quantities.
4. Pick and Place File – guides the automated machines on where to place each component on the PCB.
What Software to Use for PCB Design?
Choosing the right software can make the design process much easier, especially for beginners. Here are a few commonly used PCB design tools:
KiCad: This is a free, open-source software that’s great for both beginners and professionals. It has a user-friendly interface and includes a schematic editor, PCB layout, and 3D viewer.
Eagle: Popular among hobbyists, Eagle offers a simple design process and an extensive component library. It’s free for small designs but has premium features for more advanced projects.
Altium Designer: For more complex projects, Altium Designer is an industry-standard tool with advanced features. While it’s pricier, it offers professional-grade tools for high-level PCB design.
How Do You Manufacture a PCB Board?
Manufacturing a PCB involves several steps, and understanding the process helps ensure your design is ready for production. Here’s a simplified overview:
Step 1: Designing the PCB
Using PCB design software to create the PCB layout. The design process includes defining the schematic, component placement, and trace routing. Designers must consider factors such as signal integrity, power distribution, and thermal management.
Step 2: Design Review and Engineering Questions
Once the initial design is complete, a thorough review is conducted. This includes checking for design rule violations, verifying component footprints, and ensuring all connections are correct. Engineers may raise questions about potential performance issues, manufacturability, and compliance with regulatory standards. Feedback from this review may lead to modifications to optimize the design.
Step 3: Printing the PCB Design
After finalizing the design, the PCB layout is printed onto a transparent film, which will be used as a photomask for the etching process. This film represents the layers of the PCB, including copper and solder mask layers.
Step 4: Printing the Copper for the Interior Layer
The copper layers are printed onto the laminate using a photoresist process. The photoresist is applied to the copper-clad laminate, and the printed film is exposed to UV light. The areas that are exposed to light will become soluble and can be washed away, leaving behind a copper pattern that matches the PCB design.
Step 5: Etch the Inner Layers or Core to Remove Copper
The exposed copper is etched away using a chemical process, leaving only the desired copper traces. This step must be carefully controlled to ensure the traces are of the correct width and spacing, as specified in the design. The etching process can be done using either chemical etching or laser etching.
Step 6: Layer Alignment
Once the inner layers are etched, they must be aligned correctly for lamination.
Step 7: Automated Optical Inspection (AOI)
Automated Optical Inspection is performed to check the accuracy of the printed copper layers. Any discrepancies, such as missing or misaligned traces, can be identified and corrected before proceeding to the next steps.
Step 8: Laminating the PCB Layers
The aligned layers are then laminated together using heat and pressure. It combines the different layers, including copper, dielectric, and solder mask layers, into a single, solid structure.
Step 9: Drilling
Once the layers are laminated, holes are drilled for vias and mounting holes. The drilling process requires precision, as these holes must align perfectly with the design specifications. Computer-controlled drilling machines are typically used to achieve the necessary accuracy.
Step 10: PCB Plating
After drilling, the PCB goes through an electroplating process where a conductive layer is added to the walls of the drilled holes.
Step 11: Outer Layer Imaging
Similar to the inner layers, the outer layers are prepared for imaging. A photoresist is applied, and the printed film of the outer layer design is aligned and exposed to UV light. The unwanted areas are washed away, leaving a pattern on the copper layer.
Step 12: Outer Layer Etching
The outer copper layers are then etched to remove the unprotected copper, leaving behind the desired copper traces.
Step 13: Outer Layer AOI
Another round of Automated Optical Inspection is conducted on the outer layers to ensure that the copper traces and pads are correctly formed.
Step 14: Solder Mask Application
A solder mask layer is applied to protect the PCB and prevent solder from bridging between components during assembly. The solder mask is typically a green epoxy coating, but it can also be available in other colors. The areas where solder is needed are left exposed.
Step 15: Silkscreen Application
Silkscreen printing is used to apply labels, component designators, logos, and other markings onto the PCB surface.
Step 16: Finishing the PCB
The finishing process includes applying surface finishes such as HASL (Hot Air Solder Leveling), ENIG (Electroless Nickel Immersion Gold), or OSP (Organic Solderability Preservative) and so many surface treatments.
Step 17: Electrical Reliability Test (E-test)
Before packaging, the PCBs undergo electrical testing to ensure that all circuits function correctly. This may include continuity testing, insulation resistance testing, and high-voltage testing.
Step 18: Profiling and Route Out
The final PCB is profiled and routed to its specific shape, including cutting out the edges and any slots or cutouts required.
Step 19: Quality Check and Visual Inspection
A final quality check and visual inspection are performed to ensure that all specifications have been met. Examining for any physical defects, such as scratches, solder mask misalignment, or improper solder application.
Step 20: Packaging and Delivery
Once all checks are complete, the PCBs are cleaned, packaged, and prepared for delivery. Proper packaging is essential to protect the PCBs during shipping.
What Is the Cheapest PCB Finish?
The cheapest finish is HASL, which is also widely used. HASL applies a thin layer of molten solder to the surface, providing good protection and easy solderability. However, it’s not always suitable for fine-pitch components or designs requiring a flat surface. Other options, such as ENIG (Electroless Nickel Immersion Gold), are more expensive but provide a smoother, more durable finish for advanced designs.
Developing a PCB for the first time can feel like a daunting task, but by understanding the basics and using the right tools, it’s a process that anyone can learn. From following simple design rules to choosing affordable software and finishes, creating a PCB can be a good experience. Working closely with manufacturers and learning through trial and error will sharpen your skills over time.
How Much Does It Cost to Get a PCB Board Made?
The cost of producing a PCB depends on several factors, such as the size, number of layers, material used, and whether you’re doing a prototype run or full production. For a simple, single-sided board, costs can start as low as $10 to $20 per board, but more complex, multi-layer designs can cost upwards of $100 or more per board.
Additional costs may include shipping, testing, and assembly if you are having components mounted by the manufacturer. It’s always a good idea to get quotes from multiple manufacturers and consider both cost and quality.
If you don’t want to develop a PCB board by yourself, choosing a reliable EMS PCB manufacturer like Best Technology. We are engaging in PCB manufacturing over 18 years, we deeply understand every design rules and know which one is best for manufacturing. Best Team offer full turnkey PCB & PCBA service for over the world. We can help to PCB design, PCB layout, PCB manufacturing, components sourcing, PCB assembly, box building, and function testing. Give us your ideal, we can make it come true!
In the electronic manufacturing process, it is usually necessary to divide a large area of ​​aluminum-based PCB into multiple small pieces so that they can be installed in different electronic devices. Different electronic devices have different requirements for the size of PCBs. Through depaneling, large-area aluminum-based PCBs can be cut into sizes suitable for specific electronic devices.
What is the meaning of depaneling?
Aluminum PCB depaneling refers to cutting multiple circuit boards arranged in a row from a large board into separate small boards. This process is to divide a large aluminum printed circuit board (PCB) into multiple independent and fully functional circuit boards for subsequent assembly and use.
Aluminum PCB depaneling is an important link in the production process of electronic devices, which can improve production efficiency and circuit board flexibility.
What are the methods of PCB depaneling?
There are many ways to depanel aluminum PCBs. Common depaneling methods include:
1. ‌V-cut depaneling‌: Use a V-shaped blade to cut a V-shaped groove on the PCB board, and then separate the aluminum PCB along the groove by external force. This method is suitable for smaller aluminum PCB boards and fine dividing lines.
2. ‌Sawtooth depaneling‌: Cut the aluminum PCB board with a sawtooth cutting tool to form multiple small panels, and then separate the panels by pressure or vibration. This method is suitable for aluminum PCB boards with larger areas.
3. ‌Laser depaneling‌: Use a high-energy-density laser beam to accurately cut the aluminum PCB, which is suitable for production environments with high precision requirements and high efficiency.
4. ‌Chemical corrosion depaneling‌: Corrode the aluminum PCB with a chemical corrosive agent to form a dividing line, and then separate the panels by physical methods.
What is the process of depaneling PCB?
The aluminum PCB depaneling process varies depending on the depaneling method. The common aluminum PCB depaneling methods and processes are as follows:
Manual depaneling
Preparation: Check whether the aluminum PCB board meets the conditions for manual depaneling, such as confirming that there are no stress-sensitive components such as SMD (Surface Mounted Devices) on the board, and prepare suitable fixtures and operating space.
Positioning and fixing: Place the aluminum PCB concatenated or assembled boards that need to be separated on a stable workbench and fix them with fixtures to ensure that the boards do not move during the separation process. For aluminum PCB boards with V-grooves, align the V-grooves with the direction that is convenient for force application, and ensure that the board is placed in the correct direction and position to facilitate the separation operation.
Separation operation: The operator uses both hands or simple tools (such as tweezers, etc., and small cutting tools may be used in some special cases, but they must be operated with caution to avoid damaging the board) along the V-groove to break or separate the aluminum PCB board into individual small boards with appropriate force. During the operation, pay attention to controlling the force and direction to avoid damage to the board due to uneven force or wrong direction.
V-cut board separation machine separation
Equipment debugging: Turn on the power of the V-cut board separation machine, and adjust the upper guide knife position and lower knife height of the board separation machine according to the thickness of the aluminum PCB board, the depth and width of the V-groove and other parameters to ensure that the spacing between the upper and lower knives is appropriate and the aluminum PCB board can be accurately cut.
Upper board positioning: carefully place the aluminum PCB board with V groove on the workbench of the V-cut board splitter, ensure that the V groove of the aluminum PCB board fits tightly with the lower knife of the board splitter, and the position of the board is accurate to avoid deviation during the cutting process.
Board splitting operation: start the V-cut board splitter manually, electrically or pneumatically, so that the blade cuts along the V groove of the aluminum PCB board. During the cutting process, pay attention to the cutting situation to ensure that the cutting depth is moderate and will not cause over-cutting or incomplete cutting of the aluminum PCB board.
What is the manufacturing process of aluminum PCB?
The manufacturing process of aluminum substrate PCB mainly includes the following steps: cutting, drilling, dry and wet film imaging, etching, surface treatment and final inspection. ‌
1. Cutting: Cut the large-sized incoming materials into the size required for production, pay attention to the protection of the aluminum and copper surfaces, and avoid scratches and board edge delamination.
2. Drilling: Position the holes in the board to ensure the correct number and size, and avoid scratches on the board and deviation of the hole position.
3. Wet and dry film imaging: Present the parts required for making the circuit on the board, and pay attention to whether the circuit is open and whether the alignment is deviated after development.
4. Etching: Remove the uncovered parts to form the circuit pattern, and pay attention to the quality and stability of the circuit after etching.
5. Surface treatment: Perform necessary surface treatment on the circuit board, such as tin spraying, to improve the performance and appearance of the circuit board.
6. Final inspection: Perform a final inspection on the completed circuit board to ensure that the quality meets the requirements.
What are the advantages of aluminum PCB?
The main advantages of aluminum substrate PCB include:
Excellent heat dissipation performance: The aluminum substrate uses high thermal conductivity aluminum alloy as the core material, which can quickly conduct and dissipate heat, thereby effectively reducing the operating temperature of components.
‌Lightweight design‌: Compared with traditional FR4 substrates, aluminum substrates have lighter weight, which is particularly important in weight-sensitive fields such as aerospace and automobiles, helping to reduce the weight of the overall equipment and improve energy efficiency and operating performance‌.
‌Good mechanical properties‌: Aluminum substrates have high strength and hardness, providing good support and protection for electronic components. At the same time, its excellent impact resistance and vibration resistance enable it to adapt to various complex working environments and ensure the stable operation of the equipment‌.
‌Excellent electrical performance‌: Aluminum substrates have excellent insulation and voltage resistance, which can meet the electrical requirements of electronic equipment in various working environments and provide stable electrical support for the equipment‌.
‌Environmental protection‌: Aluminum substrates are made of environmentally friendly materials, there is no pollution in the production process, and waste is easy to recycle and dispose, which is fully in line with the current trend of green environmental protection‌.
‌Diverse application forms‌: There are many types of aluminum substrates, including flexible aluminum substrates, hybrid aluminum substrates, multi-layer aluminum substrates, etc., suitable for different application needs.
What are the disadvantages of aluminum PCB?
The main disadvantages of aluminum PCB include high cost, difficult process, electrical strength and withstand voltage problems, mismatched thermal conductivity test, inconsistent material specifications, and more defective products. ‌
First, the price of aluminum PCB is relatively high, usually accounting for more than 30% of the product price. This is because the production of aluminum PCB requires the use of high-purity aluminum materials and special processing technology, all of which push up the cost. ‌
Second, the process of aluminum PCB is difficult, especially when it is made into a double-sided board, the process complexity is higher, and it is easy to have problems in electrical strength and withstand voltage. In addition, the mismatch of thermal conductivity test methods and results of aluminum PCB is also a problem. ‌
In addition, the material specifications of aluminum PCB have not yet been unified, and there are multiple standards such as CPCA industry standards, national standards, and international standards, which brings certain uncertainties to production and application. ‌
Why is aluminum no longer used in integrated circuits?
The main reason why aluminum is no longer used in integrated circuits is that copper has replaced aluminum as an interconnect metal material. Copper has lower resistivity and better anti-electromigration performance than aluminum, which makes copper more reliable and effective in high-speed integrated circuits. ‌
Specifically, aluminum may experience electromigration under long-term current, that is, aluminum atoms migrate inside the wire, causing the wire to break or form voids, which in turn causes the integrated circuit to fail. In addition, as the interconnection spacing decreases, the resistance of the aluminum wire increases and the capacitance between the wires increases, resulting in increased RC delay, which is not conducive to high-speed integrated circuits.
Copper has a lower resistivity than aluminum, can transmit current more efficiently, and can carry more current in thinner metal wires. Copper also has higher electromigration resistance than aluminum, making copper interconnects more reliable under high current conditions. These advantages make copper a preferred material for advanced integrated circuit technology.
Aluminum-based PCB depaneling is an important link in the electronic manufacturing process, which directly affects the quality and performance of electronic equipment. By selecting the appropriate depaneling method, controlling the depaneling accuracy, and avoiding damage to the PCB, the quality and efficiency of aluminum-based PCB depaneling can be effectively improved.
There are many differences between single sided and double sided PCB in terms of structure, performance, application scenarios, etc. Single-sided PCB has conductive lines on only one side, while double-sided PCB has conductive lines on both sides, which makes them perform differently in terms of the complexity of circuit layout, signal transmission capability, and the types of electronic devices they are suitable for.
What is the difference between single and double sided PCB?
The main difference between single-sided PCB and double-sided PCB lies in their structure and use. Single-sided PCB has only one layer of lines, which is suitable for simple circuits; while double-sided PCB has two layers of lines, which is suitable for complex circuits.
The characteristics and application scope of single-sided PCB are as follows:
1. Structure: Single-sided PCB has only one layer of lines, and all components are on the same layer and connected by copper foil lines.
2. Application scope: Usually used for simple circuits, such as LED lights, alarm clocks, etc.
3. Advantages: Low manufacturing cost and simple manufacturing process.
4. Disadvantages: Only simple circuit layout can be realized, and the crossing of lines will increase the size of the board, which is not suitable for complex circuit layout.
The characteristics and application scope of double-sided PCB are as follows:
1. Structure: Double-sided PCB has two layers of lines, and components can be arranged and connected on two levels, and connected to each other through jacks and pads.
2. Application scope: Usually used for complex circuits, such as computers, mobile phones, etc.
3. Advantages: Complex circuit layout can be realized, and the crossing of lines will reduce the size of the board.
4. Disadvantages: The manufacturing cost is high, and the manufacturing process is more complicated than that of single-sided PCB, which is not suitable for ultra-large circuit layout.
The differences in materials and processes between single-sided PCB and double-sided PCB are as follows:
1. Material: Single-sided board has copper foil on only one side, while double-sided board has copper foil on both sides.
2. Process: The solder joints of single-sided board are basically on one side, and components are inserted on the other side; both sides of double-sided board can be soldered, with plug-in components and SMD components.
Why use single sided PCB?
Single-sided PCB is mainly used for simple circuit design and cost-sensitive applications. Since there is only one side of the single-sided board with wiring, the wiring is difficult, so it is mainly suitable for simple circuit design.
The advantages of single-sided PCB include low cost and relatively simple manufacturing process. Since the manufacturing process of single-sided board is relatively simple and does not require complex multi-layer wiring and connection, the cost is low and suitable for mass production.
What is the advantage of single layer PCB?
The main advantages of single-layer PCB include:
1. Low cost: The manufacturing cost of single-layer PCB board is relatively low, because only one layer of copper foil and one layer of substrate are required, the manufacturing process is relatively simple, and the material cost is low.
2. Easy to make: Compared with other structural types of PCB boards, the manufacturing method of single-layer PCB board is relatively simple, only single-sided wiring and single-layer corrosion are required, the manufacturing difficulty is low, the drilling, welding and installation of components are relatively simple, and it is unlikely to cause production problems.
3. High reliability: Single-layer PCB board does not have multi-layer wiring and connection, so it is not easy to have problems such as short circuit and interference, and has high reliability.
4. Suitable for simple circuits: Single-layer PCBs are suitable for simple circuit designs, such as LED lights, household appliances, etc., and can meet most low-complexity circuit requirements.
What are the disadvantages of single sided PCB?
First, the difficulty of wiring a single-sided PCB is a significant disadvantage. Since there is only one layer of copper foil, wiring is difficult, and the layout of the circuit and the location of components need to be carefully planned to avoid short circuits or circuit failures caused by improper wiring.
Second, the electromagnetic interference suppression capability of single-sided PCBs is relatively poor. In high-frequency circuits, the electromagnetic interference problem of single-sided PCBs will be more prominent and become an important factor to be considered during design.
Finally, single-sided PCBs limit the complexity of the circuit. Since it has only one layer of copper, it is not suitable for the design of complex circuits. For circuits that require high complexity, double-sided or multi-layer PCBs would be a better choice.
1. Enhanced circuit density: The available surface area of ​​double-sided PCBs is doubled, and more components can be attached.
2. Higher signal transmission rate: Double-sided PCB design makes the circuit more complex and flexible, thereby improving the signal transmission rate and circuit performance.
3. More reliable circuit connection: By passing the circuit through holes between the two sides, the circuit can be connected on both sides, greatly improving the density and reliability of the circuit board.
4. Convenient wiring and debugging: The design of double-sided PCB makes wiring more flexible, convenient for complex circuit design, and also convenient for subsequent debugging and maintenance.
5. Environmental protection and high efficiency: Double-sided PCBs are made of non-toxic and pollution-free materials, which meet environmental protection requirements, and can carry more electronic components and improve the working efficiency of equipment.
Where are double sided PCBs used?
The characteristic of double-sided PCBs is that both sides can be wired and assembled with electronic components, and the lines on both sides are connected through holes (vias), so as to achieve more complex circuit design.
This design makes double-sided PCBs perform well in application scenarios that require high-density assembly and complex circuit layout. Due to the presence of vias, double-sided PCBs can achieve more complex circuit designs without significantly increasing the size of the circuit board.
Specific application areas include:
1. Computer and industrial control: Double-sided PCBs are widely used in computer motherboards and industrial control systems, providing complex circuit designs and high-density component layouts.
2. Communication equipment: In communication equipment, double-sided PCBs are used to achieve high-density signal processing and transmission, supporting various communication protocols.
3. Consumer electronics: In devices such as smartphones, tablets, routers, etc., double-sided PCBs are used to achieve complex circuit functions and efficient space utilization.
4. Aerospace: In the high-tech field, double-sided PCBs are used for applications with high performance requirements and strict space constraints.
What are the two sides of a PCB called?
The two sides of a PCB are called the top layer and the bottom layer. ‌
The top layer is usually used to place and layout electronic components such as chips, resistors, capacitors, etc. The pins, wires, identifiers, and markings of the components can be seen on this layer. The top layer is also called the component side.
The bottom layer is mainly used to connect the pins of electronic components and connect to the top layer through appropriate wires. In this layer, you can see the pads, vias, connections, and possible ground and power planes. The bottom layer is also called the solder side.
In addition to the top and bottom layers, PCBs may also contain other layers, such as signal layers, power/ground layers, mechanical layers, solder mask layers, solder paste protection layers, and no-routing layers. These layers play different roles in PCB design, such as providing circuit routing, mechanical support, and preventing short circuits.
Can you put components on both sides of a PCB?
Components can be placed on both sides of a PCB. The design of double-sided PCBs allows components and wiring to be placed on both sides of the circuit board, thereby increasing the complexity and functionality of the circuit.
Design features of double-sided PCBs include:
Dual use of wiring and components: Both sides of a double-sided PCB can be used for wiring and component placement, which greatly increases the complexity and functionality of the circuit.
Via connection: In order to achieve interconnection between components and wiring on a double-sided PCB, connections need to be made through vias. A via is a small hole filled or coated with metal that connects wires on both sides.
The use scenarios of double-sided PCBs include:
Increasing circuit density and functionality: Double-sided PCBs increase the layout space for components, allowing designers to achieve more functions without increasing the size of the circuit board, which is particularly suitable for occasions that require high-density integration and complex circuit design.
In short, single-sided and double-sided PCBs differ significantly in many aspects. Both single-sided and double-sided PCBs contribute to the vigorous development of the electronics industry and continue to help electronic technology move forward. BEST Technology has abundant upstream and downstream resources for circuit boards, and can quickly and efficiently meet customers’ various needs for circuit boards.
Thermal conductivity refers to a material’s ability to conduct heat. It’s a physical property that indicates how easily heat can pass through a substance when there is a temperature difference. In scientific terms, thermal conductivity is measured in watts per meter-kelvin (W/m·K), describing how much heat (in watts) is transferred through a material for every meter of thickness when there’s a one-degree temperature difference across it.
For ceramic materials, thermal conductivity plays a pivotal role in determining their usability in various industrial and electronic applications. Materials with high thermal conductivity can transfer heat quickly, so it is important in situations where heat must be dissipated rapidly to avoid damage to components, like in electronics or aerospace industries. On the other hand, materials with low thermal conductivity are used for thermal insulation, preventing unwanted heat transfer in applications like kiln linings or fireproofing.
Do Ceramic Materials Have High Thermal Conductivity?
Ceramic materials are generally known for their thermal insulation properties, meaning they typically have low thermal conductivity. However, not all ceramics are insulators. There are a few exceptions with significantly higher thermal conductivity, making them valuable for heat-dissipating applications.
Traditional ceramics such as alumina and zirconia are typically poor conductors of heat due to their atomic structure, which restricts the movement of heat. However, advanced ceramics like aluminum nitride (AlN) and silicon carbide (SiC) exhibit impressive levels of thermal conductivity. These materials are increasingly being used in industries like electronics, aerospace, and automotive manufacturing, where managing heat efficiently is critical to the performance and safety of equipment.
High thermal conductivity ceramics, though less common, have opened new avenues for using ceramic materials in areas where heat transfer was traditionally a limiting factor. So, while most ceramics are not known for high thermal conductivity, advancements in ceramic technology have led to the development of high-performance materials that challenge this generalization.
Why is Thermal Conductivity Important for Ceramic Materials?
Thermal conductivity in ceramics is a key factor that dictates where and how these materials can be used. There are several reasons why thermal conductivity matters for ceramic materials:
Heat Management in Electronics
In electronics, high thermal conductivity ceramics are crucial to ensure that components do not overheat during operation. Many electronic devices produce heat as a byproduct, and if this heat is not managed properly, it can lead to equipment failures. Ceramic materials like AlN and BeO are widely used in applications such as LED packaging, power electronics, and semiconductor manufacturing due to their ability to transfer heat away from sensitive components quickly and efficiently.
Thermal Insulation
On the flip side, some ceramic materials with low thermal conductivity are perfect for insulation. In industries like metallurgy or construction, materials like silicon oxide or zirconia are used to keep heat in or out, making them excellent choices for furnace linings, kilns, and thermal barrier coatings.
Thermal Shock Resistance
Many ceramics with low thermal conductivity also possess high thermal shock resistance, meaning they can withstand rapid temperature changes without cracking or breaking. This is important in applications such as aerospace, where materials are often exposed to extreme temperature variations.
Energy Efficiency
Thermal conductivity affects the energy efficiency of systems. In applications like heating elements, components with good thermal conductivity allow heat to be transferred more effectively, leading to better energy efficiency and lower operational costs. Ceramics that balance both thermal insulation and conductivity provide optimized energy management, crucial for industrial processes.
5 Typical High Thermal Conductivity Ceramic Materials
Aluminum Nitride (AlN)
Thermal Conductivity: ~170-230 W/m·K
Aluminum nitride is one of the most well-known ceramics for high thermal conductivity. It is electrically insulating, which makes it an ideal material for electronic substrates and heat sinks in devices like LEDs and power modules. Its ability to rapidly dissipate heat while maintaining electrical isolation makes it a popular choice in electronics where heat management is critical.
Silicon Carbide (SiC)
Thermal Conductivity: ~120-270 W/m·K
Silicon carbide is not only known for its excellent thermal conductivity but also its incredible hardness and mechanical strength. It is used in high-temperature applications, such as in gas turbines and heat exchangers. Its ability to withstand harsh conditions while transferring heat efficiently makes it invaluable in aerospace and automotive industries.
Beryllium Oxide (BeO)
Thermal Conductivity: ~200-330 W/m·K
Beryllium oxide offers one of the highest thermal conductivities among ceramics, rivaling some metals. Its superior ability to conduct heat while remaining electrically insulating makes it ideal for high-performance electronic devices. However, its use is limited due to the toxic nature of beryllium, requiring careful handling during manufacturing.
Alumina (Al2O3)
Thermal Conductivity: ~20-35 W/m·K
Alumina is a widely used ceramic due to its good combination of thermal conductivity, mechanical strength, and electrical insulation. Though not as high in thermal conductivity as AlN or SiC, alumina’s affordability and versatility make it a common choice in many industrial applications, including substrates for electronics and thermal barriers.
Silicon Nitride (Si3N4)
Thermal Conductivity: ~20-30 W/m·K
Silicon nitride is a material prized for its thermal shock resistance and mechanical strength. Though it does not have the highest thermal conductivity, its ability to withstand extreme temperatures and thermal cycling makes it valuable in engines and high-performance bearings.
What Ceramic Materials Are Best for Thermal Conductivity?
Aluminum nitride is one of the most suitable ceramic materials for conducting heat. ‌ aluminum nitride (AlN) has a thermal conductivity of 170-230 W/mK, is one of the best thermal conductivity ceramic substrate materials, especially suitable for high power density and high-frequency electronic devices heat. Aluminum nitride is suitable for heat conduction, mainly for the following reasons:
1. High thermal conductivity: aluminum nitride has extremely high thermal conductivity and can effectively transfer heat from one area to another.
‌2. Excellent mechanical properties: aluminum nitride not only has good thermal conductivity, but also has high mechanical strength and chemical stability, can maintain the stability of its structure and properties in a variety of environments.
‌3. Wide application: aluminum nitride is widely used in the heat dissipation of high power density electronic devices and high-frequency electronic devices to meet the needs of modern electronic equipment for efficient heat dissipation.
What are the Thermal Properties of Ceramic Materials?
The thermal properties of ceramic materials mainly include melting point, heat capacity, thermal expansion and thermal conductivity. ‌ The melting point of ceramic materials is generally higher than that of metals, up to 3000℃ or more, and has excellent chemical stability at high temperatures‌.
The heat capacity of ceramic materials refers to the heat required to increase the temperature of ceramic materials by 1℃ per unit mass. Ceramic has a lower heat capacity, which means that it is less able to absorb heat when heated‌.
The coefficient of thermal expansion of ceramic materials is small, much lower than that of metal. This means that when the temperature changes, the size of the ceramic changes less and has good dimensional stability.
The thermal conductivity of ceramic materials is lower than that of metal materials, but its thermal conductivity depends on the specific type of ceramic. Some ceramics are good thermal insulation materials, while some ceramics are good thermal conductivity materials, such as boron nitride and silicon carbide ceramics.
Your Most Reliable Ceramic PCB Manufacturer – Best Technology
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Whether you need ceramic materials with high thermal conductivity for your electronics, or specialized products for unique applications, we have the expertise and the technology to deliver. Trust Best Technology to provide you with the best in ceramic PCB manufacturing, ensuring that your projects are completed to the highest standards.
Aluminum nitride PCB also known as Aluminum nitride ceramic PCB or short for AlN PCB. It is a high-performance circuit board made from aluminum nitride ceramic, a material known for its exceptional thermal conductivity and electrical insulation properties. These boards are commonly used in industries where efficient heat dissipation is crucial, such as in power electronics, LED applications, and high-frequency devices. AlN PCBs are gaining popularity due to their ability to withstand extreme temperatures.
Benefits of AlN PCBs
One of the key advantages of AlN PCBs is their excellent thermal conductivity, which helps prevent overheating in electronic components. With exceptional thermal conductivity of 170 W/mK, strong dielectric strength, and a low thermal expansion coefficient (CTE <4 ppm/°C), AlN is widely used in applications like high-power LEDs, lasers, high-current switches, and even ultra-low temperature vacuum electronics such as those in quantum computing. In addition to these features, AlN offers the same benefits as other ceramic materials, including rigidity, environmental and chemical resistance, and 0% water absorption.
Key reasons for choosing Aluminum Nitride over other PCB materials include:
Outstanding thermal conductivity of 170 W/mK
Excellent dielectric properties
High operating temperatures exceeding 350°C
Low thermal expansion coefficient (<4 ppm/°C)
Compact designs due to better integration
Hermetically sealed packages with 0% water absorption
Minimal to no outgassing
What is the Thermal Conductivity of Aluminum Nitride PCB?
‌The thermal conductivity of aluminum nitride PCB ranges from 170-230W/(m·K).
The high thermal conductivity of aluminum nitride PCB is due to its unique structure and chemical composition. The thermal conductivity of aluminum nitride ceramic substrate is 2-3 times higher than that of traditional alumina ceramics and silicon-based ceramics, and 10-20 times higher than that of titanium substrate. This high thermal conductivity allows them to effectively dissipate heat from high-power electronic components, preventing overheating and ensuring stable performance. The ability to manage heat efficiently makes AlN PCBs an ideal choice for applications that generate a significant amount of heat, such as power modules, LEDs, and RF components. In comparison to other materials like aluminum oxide, which has lower thermal conductivity (around 20-30 W/mK), aluminum nitride stands out as a top choice for heat-sensitive applications.
Factors affect thermal conductivity of AlN PCB
Although the theoretical thermal conductivity of AlN is extremely high, its performance in practical applications is limited by a number of factors, mainly including:
Microstructure
Phonon scattering is a key mechanism for heat conduction. Grain boundaries, interfaces, second phases, and defects can all affect the mean free path of phonons, thereby influencing thermal conductivity. High-purity, low-defect single-crystal AlN has a longer phonon mean free path and higher thermal conductivity.
Oxygen Impurity Content
AlN’s strong affinity with oxygen leads to the easy introduction of oxygen impurities, which form alumina films and lattice defects, such as aluminum vacancies. These significantly reduce the phonon mean free path, lowering thermal conductivity. When the oxygen concentration is below 0.75%, oxygen atoms primarily replace nitrogen atoms in the lattice; however, exceeding this concentration causes aluminum vacancies to disappear and results in the formation of extended defects, further affecting thermal conductivity.
Sintering Process and Additives
By selecting appropriate sintering additives (such as Y₂O₃-Li₂O, Y₂O₃-CaC₂ composite systems), densification can be achieved at lower temperatures, while reducing the formation of oxygen impurities and second phases, effectively improving the thermal conductivity of AlN ceramics. These additives help purify grain boundaries and optimize the microstructure, facilitating more efficient phonon transmission.
What is Aluminum Nitride PCB Used For?
Aluminum nitride as a stable hexagonal wurtzite covalent bond compound, has shown extensive application potential in the field of electronics and optoelectronics due to its unique physical and chemical properties. Its crystal structure takes AlN4 tetrahedron as the basic unit, space group P63mc, belongs to the hexagonal crystal system, which gives AlN a series of excellent properties and use in advanced applications.
Some common applications include:
Optical Communication
Integrated Circuits and High-Power Electronic Devices
Power Electronics
Wafer chips
Epoxy Resin Packaging
Optical Devices and Piezoelectric Devices
Industrial Materials
Acoustic Devices
Aerospace
Military
Why is Aluminum Nitride Expensive?
The high cost of aluminum nitride PCBs stems from several factors.
First of all, the raw material cost of aluminum nitride PCB is higher. The preparation of aluminum nitride powder requires high purity raw materials, synthesis methods include direct nitriding method, carbothermal reduction method, self-propagating high temperature synthesis and chemical vapor deposition method, etc. These methods have high requirements on equipment and technology, resulting in higher costs.
Secondly, the production process is complicated. The preparation process of aluminum nitride PCB is complex, including multiple steps such as molding and sintering, which has high requirements for equipment and technology and a high production threshold.
Finally, the market demand is large. Aluminum nitride PCB in power electronics, communication equipment, automotive electronics and other fields have a wide range of applications, especially in high power, high frequency and other occasions, its excellent heat dissipation and insulation performance can not be replaced, resulting in short supply in the market, the price of natural rising.
Aluminum Nitride PCB vs. Alumina Oxide PCB
Both aluminum nitride (AlN) and alumina oxide (Al2O3) are ceramic materials used in PCB manufacturing, but they differ significantly in terms of performance. AlN offers superior thermal conductivity, typically 170-230 W/mK, compared to aluminum oxide’s lower range of 20-30 W/mK. This makes AlN the better option for applications requiring efficient heat dissipation, such as high-power electronics and LED lighting.
However, aluminum oxide is more cost-effective and is often used in applications where high thermal conductivity is not as crucial. While Al2O3 provides good electrical insulation and is easier to produce, it may not perform as well in heat-sensitive environments as AlN. Therefore, the choice between AlN and Al2O3 depends on the specific thermal and budgetary requirements of the application. Here are the parameters of AlN and Al2O3 materials:
Parameter
Aluminum Nitride (AlN)
Alumina Oxide (Al2O3)
Thermal conductivity
170-230 W/m.k
24-30 W/m.k
Dielectric constant
8.8
9.2-10
Dielectric strength
15-25kV/mm
10-15kV/mm
Temperature resistance
1000-1500C
1000-1200C
CTE
4.0 ppm/K
6.5-7 ppm/K
Flexural strength
450MPa
320MPa
Dielectric breakdown voltage
14 V/m
10 V/m
AlN Ceramic PCB Design Considerations
When designing an aluminum nitride PCB, several factors need to be considered to optimize performance:
1. Trace Width
The trace width on AlN PCBs should be a minimum of 10 mils. This ensures that the conductor cross-section is sufficient to handle the current and heat dissipation needs. Given the thermal advantages of AlN, wider traces help in spreading heat more efficiently, minimizing the risk of overheating in power-dense applications.
2. Trace Clearance
Clearances between adjacent traces should be at least 8 to 10 mils. AlN PCBs often work with higher voltage levels, making spacing critical to prevent arcing or dielectric breakdown. In high-power designs, careful spacing between traces reduces the likelihood of signal interference and maintains the board’s insulation integrity.
3. Via Pads
For via pads, a minimum diameter of 16 mils is recommended. This provides sufficient area for stable soldering and ensures proper electrical connection through the via. Depending on the board’s application, larger via pads may be necessary to accommodate higher currents or thermal dissipation needs. Via sizing should also account for assembly techniques, such as reflow soldering or thermal management features, like thermal vias, which enhance heat transfer away from components.
4. Pad Geometry Adjustments
Unlike FR-4 designs, AlN PCBs often require specific adjustments in pad geometries. The mechanical and thermal properties of AlN are quite different from those of traditional PCBs. The expansion rate, hardness, and substrate fragility mean that pad designs should allow for thermal expansion and contraction without causing stress fractures. Proper pad design also ensures better solder joint reliability, particularly for components exposed to continuous thermal cycling.
5. Gold Plating for Wire Bonding Pads
In high-performance applications, wire bonding is often used, and gold plating is a preferred surface finish for wire bonding pads. The use of gold provides a stable, corrosion-resistant surface that improves bond integrity and longevity. Wire bonding is especially critical in high-frequency, high-reliability devices, where the connections must maintain integrity under thermal stress or in harsh environments.
6. Component and Solder Matching
All components and solder materials must match the electrical and mechanical properties of the AlN substrate. Mismatches in thermal expansion between the PCB material and components can lead to stress, causing cracking or delamination. It’s important to select components and solder that can withstand high temperatures and thermal cycles while maintaining compatibility with AlN’s characteristics, especially in applications like power electronics and RF circuits.
7. Hermetic Sealing and Height Restrictions
For applications requiring hermetic sealing, such as aerospace or medical devices, height restrictions may apply to the components on the PCB. Hermetic seals protect against moisture and environmental contaminants, ensuring long-term reliability in sensitive applications. The overall component height should be kept in line with the sealing requirements, and compact designs are often necessary to meet stringent packaging constraints.
8. Thermal Expansion Management
When attaching large dies or high-power devices, it’s crucial to model and account for thermal expansion. Even though AlN has a low thermal expansion coefficient (<4 ppm/°C), the difference in expansion rates between components and the substrate can create mechanical stress, especially during thermal cycling. Careful design, including flexible connections or underfill materials, can help mitigate these effects.
9. Thermal Vias
Thermal vias are essential for managing heat in high-power applications. By placing thermal vias directly underneath hot components, heat can be efficiently transferred away from sensitive areas, extending the lifespan of both the components and the PCB itself. In many designs, a network of thermal vias is integrated with heat sinks or spreaders to further improve heat dissipation.
10. Surface Finishes and Coatings
Aluminum nitride PCBs can benefit from surface finishes such as electroless nickel immersion gold (ENIG) or immersion silver, which protect the copper traces from oxidation and provide excellent solderability. The choice of surface finish may also depend on the specific application environment and the reliability requirements, especially in high-power or high-frequency circuits.
FAQs About AlN PCBs
1. How durable are aluminum nitride PCBs?
AlN PCBs are highly durable and can withstand extreme temperatures and harsh environments.
2. Can AlN PCBs be used in high-frequency applications?
Yes, aluminum nitride PCBs are well-suited for high-frequency and high-speed applications due to their excellent electrical insulation and low signal loss.
3. Are aluminum nitride PCBs environmentally friendly?
While the production process can be resource-intensive, AlN PCBs offer longer lifespans and higher efficiency, which can reduce the environmental impact over time.
4. How do AlN PCBs compare with metal-core PCBs?
Metal-core PCBs, such as those with an aluminum core, provide good thermal management but lack the superior electrical insulation of AlN PCBs. AlN PCBs are preferred for applications requiring both high thermal conductivity and insulation.
5. What industries typically use aluminum nitride PCBs?
Industries like power electronics, aerospace, automotive, and telecommunications commonly use AlN PCBs for their high-performance needs.
A 2-layer aluminum PCB is a type of metal core circuit board that contains two conductive layers, usually copper, with an aluminum core or base material. Aluminum PCBs are used for their excellent heat dissipation properties, and always used in high-power applications like LED lighting, power supplies, and automotive systems. The aluminum base offers better thermal management than standard FR4 PCBs. In a 2-layer aluminum PCB, the two conductive copper layers allow more complex routing for electrical signals compared to single-layer boards.
2 Layer Aluminum PCB Stack-Up
The stack-up of a 2-layer aluminum PCB consists of the following:
Top Copper Layer: This is where the signal traces and components are located. It can vary in thickness, depending on current-carrying requirements.
Dielectric Layer: A layer of insulation that separates the top copper layer from the aluminum core. It plays a key role in electrical isolation and heat transfer.
Aluminum Base: This core provides structural support and excellent heat dissipation properties. It also serves as the grounding plane in some designs.
Bottom Copper Layer: The second conductive layer allows for more advanced routing.
How Thick is a 2 Layer PCB Layer?
The thickness of a 2-layer aluminum PCB can vary depending on the specific design requirements, but typically, the copper layer is about 1 to 2 ounces (35 to 70 microns) thick. The aluminum base itself is thicker, usually between 1.0 mm and 3.0 mm, depending on the board’s required rigidity and heat dissipation needs. The overall board thickness generally ranges between 1.2 mm and 3.2 mm.
A thicker aluminum core improves heat transfer, but the board’s thickness must also align with the product’s mechanical and electrical requirements. Designers often have to balance between sufficient thermal performance and the overall board size for practical applications.
Is Thicker Aluminum PCB have Better Heat Dissipation?
Generally speaking, the thinner the thickness of the aluminum PCB, the faster the heat conduction speed. The thicker the thickness of the aluminum PCB, the slower the heat conduction rate. The thermal conductivity of aluminum-based circuit board mainly depends on its material and structure. Although thickness affects the path length of heat conduction, the more critical factors are the thermal conductivity and structural design of the material. For example, high thermal conductivity materials such as copper, silver and other high thermal conductivity materials will significantly improve the thermal conductivity of aluminum substrate. In addition, the thickness and thermal conductivity of the insulation layer will also affect the overall thermal conductivity effect ‌.
Specifically, the thermal conductivity of the aluminum-based circuit board is also related to the thickness of its insulation layer. The thicker the insulation layer, although it can withstand higher voltage, it will also reduce the heat transfer efficiency. Therefore, choosing the appropriate insulation layer thickness and materials with high thermal conductivity is the key to ensuring efficient thermal conductivity of aluminum-based circuit boards ‌.
2 Layers Aluminum PCB vs. Double Sided Aluminum PCB
Though the terms “2 layers aluminum PCB” and “double-sided aluminum PCB” might sound similar, there are slight differences.
A 2-layer aluminum PCB contains two conductive copper layers. These layers can be arranged to handle signal routing and ground planes separately. In contrast, a double-sided aluminum PCB typically has one copper layer on either side of the aluminum core, offering less flexibility in routing. Here is the stack up of double sided aluminum PCB:
How Much Does Aluminum PCB Cost?
The cost of an aluminum PCB, including a 2-layer version, depends on several factors such as the board’s thickness, copper weight, design complexity, and production volume. On average, 2-layer aluminum PCBs cost more than single-sided aluminum PCBs because of the additional copper layer and routing complexity.
For small orders, prices might range between $5 and $15 per square foot. For larger production runs, costs can decrease significantly due to economies of scale. Factors like the thickness of the aluminum base and copper layer, as well as additional features like surface finishes, can also influence the price.
While aluminum PCBs are more expensive than standard FR4 boards, their enhanced thermal performance can reduce overall system costs by improving reliability and reducing the need for additional cooling measures.
How Many Layers Should a PCB Have?
The number of layers a PCB should have depends on the complexity of the design. For simple applications like LED lighting or power conversion, a 2-layer aluminum PCB is often sufficient. It provides more routing flexibility than a single-layer board while still offering effective heat dissipation.
For more complex designs requiring high-density interconnections or additional functionality, a multi-layer PCB with three or more layers might be necessary. However, multi-layer aluminum PCBs are rare because their primary function is thermal management, which is typically solved within one or two layers. The decision to use more layers depends on the specific application, power requirements, and signal integrity needed in the design.
Aluminum PCB Design Guidelines
When designing a 2-layer aluminum PCB, several factors must be considered to maximize performance:
Thermal Management: Since aluminum PCBs are chosen for their thermal properties, optimizing heat dissipation is critical. Components that generate significant heat should be placed near the aluminum core, allowing for faster heat transfer.
Copper Thickness: The copper thickness should match the current-carrying requirements of the design. Using thicker copper can help manage higher current loads, but it also increases the cost and weight of the PCB.
Dielectric Layer: The thickness and material of the dielectric layer play a crucial role in both thermal and electrical performance. A thinner dielectric layer improves heat dissipation but may limit electrical isolation. Choosing the right dielectric material is key for balancing performance and reliability.
Via Placement: For a 2-layer design, vias must be carefully placed to connect the two copper layers. Vias should be positioned to minimize electrical interference and maintain signal integrity.
Component Placement: Heat-sensitive components should be placed away from high-power components. This minimizes thermal stress on sensitive devices and ensures reliable operation over the PCB’s lifespan.
Aluminum PCBs may come with a higher price tag compared to traditional FR4 boards, but the long-term benefits in heat management, performance, and durability make them an excellent investment for demanding applications. Whether you’re working on power electronics, automotive circuits, or lighting solutions, a 2-layer aluminum PCB can provide the right balance between complexity and thermal efficiency.
If you’re in need of high-quality, custom aluminum PCBs, Best Technology specializes in delivering tailored solutions for your specific design needs. With 18+ years of experience in PCB manufacturing, we ensure top-notch performance, quality, and reliability for all your projects. Let us help you bring your ideas to life with the right aluminum PCB solution!
Laser direct imaging (LDI) technology is a process that uses lasers to expose images directly on photoresists, mainly used in the exposure process of PCB manufacturing processes. LDI is a widely used technology that can create a variety of images and is used in various industries, including electronics, automotive and medical industries.
What is laser direct imaging?
Laser direct imaging (LDI) is an advanced photolithography technology. It directly uses a laser beam to expose images on photoresists, eliminating the intermediate step of making photolithography masks in traditional photolithography technology.
In this process, the laser beam is precisely controlled according to the pre-set circuit pattern data. The laser emitted by the laser light source is processed by a series of optical components, such as beam expansion and focusing, and then the laser beam is guided by the scanning system to scan and expose the surface of the printed circuit board (PCB) coated with photoresist.
The photoresist responds to the laser energy, and according to the type of photoresist (positive or negative), the corresponding chemical changes occur in the laser irradiation area. This change will lay the foundation for subsequent development and other processes, thereby forming an accurate circuit pattern.
What is the principle of laser direct imaging?
The principle of laser direct imaging (LDI) is to expose the pattern directly on the substrate coated with photosensitive material through a computer-controlled laser beam.
Specifically, the workflow of LDI includes the following steps: First, the designed circuit pattern is converted into the image generation program of the spatial light modulator through computer-aided manufacturing (CAM) software. Then, the laser beam passes through the spatial light modulator, and the generated image is projected onto the substrate coated with photosensitive material through the optical imaging system to complete the pattern exposure. Compared with the traditional mask exposure process, LDI saves the film process in the exposure process and greatly improves the production efficiency.
The main advantages of LDI technology are its efficiency and precision. It directly uses a highly focused laser beam controlled by a computer to define the circuit pattern on the PCB copper layer covered with laser photoresist without the need for photographic tools, thus avoiding the film and printing defects in the traditional process.
In addition, LDI also optimizes the production environment, eliminates the influence of temperature and humidity on the product, and further improves the production quality and efficiency.
How does laser direct imaging (LDI) work?
Laser direct imaging (LDI) technology is a process that uses laser to directly expose and image on photoresist, and is mainly used in the exposure process in the PCB manufacturing process. Its working principle is as follows:
1. Design graphics: Design the circuit graphics to be produced through computer-aided design (CAD) software.
2. Generate images: Convert the designed circuit graphics into digital images and transmit them to the control system of the LDI equipment.
3. Laser scanning: The laser beam in the LDI equipment scans and exposes the photoresist according to the information of the digital image under the precise control of the control system.
4. Photochemical reaction: The photoresist undergoes a photochemical reaction under the irradiation of the laser, changing its solubility.
5. Development: The exposed photoresist is developed in the developer to remove the unexposed part of the photoresist, thereby forming a circuit pattern on the photoresist that is consistent with the design graphics.
6. Etching or electroplating: According to needs, the developed circuit board is etched or electroplated and other subsequent processes are performed to produce the actual circuit.
Compared with traditional exposure technology, LDI technology has higher resolution and precision, can produce finer circuit wiring and smaller line spacing, and also has higher production efficiency and flexibility.
What are the advantages of using laser direct imaging?
The main advantages of LDI (Laser Direct Image) technology include: eliminating the film process in the exposure process, saving time and cost for loading and unloading films, and reducing deviations caused by film expansion and contraction; directly imaging CAM data on PCB, eliminating CAM production process; high image resolution, fine wires can reach about 20um, suitable for fine wire production; improve PCB production yield.
The main problems of LDI technology include: high-precision lasers and optical systems are required, which increases the cost and complexity of the equipment; high environmental requirements, temperature and humidity need to be controlled to ensure imaging quality; high technical requirements for operators, and professional training is required to operate the equipment proficiently.
The advantages of LDI technology in the flexible board industry include: improving production efficiency, no need to make and replace physical masks, shortening production cycles and waiting time; high-precision imaging, capable of processing finer and more complex graphics, improving product yield and reliability; efficient use of materials, reducing material waste; environmental advantages, reducing the use of chemicals, and reducing environmental pollution.
What are the disadvantages of laser direct imaging?
The disadvantages of laser direct imaging (LDI) technology mainly include:
1. High equipment cost: LDI equipment is usually expensive and requires a large initial investment, which may be a burden for some small enterprises or projects.
2. High environmental requirements: LDI equipment needs to work in a specific environment, such as a dark room or a low-illuminance red light environment, which increases the requirements for the working environment.
3. Technical complexity: LDI technology involves multiple steps and complex process flows, with high technical requirements for operators, and long training costs and time.
4. High material cost: LDI requires the use of specific photoresists and laser diodes, which are expensive and increase production costs.
5. Speckle problem: After the laser beam is reflected or transmitted through a rough surface, it will form countless independent scattered sub-waves. These sub-waves are coherently superimposed during the spatial propagation process, forming random and irregularly distributed bright and dark spots in space, that is, speckle phenomenon, which may affect the imaging quality.
In summary, although LDI technology has the advantages of high precision and high efficiency, its disadvantages such as high equipment cost, complex technical requirements and speckle problem also need to be considered when using it.
When is laser direct imaging used?
Laser direct imaging LDI is mainly used in the exposure process in PCB manufacturing, especially when high precision and efficient production are required. This technology is particularly suitable for the production of fine-line and ultra-fine-line circuit boards, and can achieve the best imaging effect.
In addition, LDI technology is also widely used in the field of FPC soft boards, which can improve production efficiency and product quality, and support complex circuit structures and high-density layouts.
The advantages of laser direct imaging LDI technology include:
1. High precision: It can achieve high-resolution pattern exposure and improve product performance and reliability.
2. Efficient production: shorten the exposure process, speed up production and reduce costs.
3. Complex circuit structure: support the exposure of multi-layer FPC and meet the needs of high-density layout.
Laser direct imaging technology is a highly promising technology in the field of PCB manufacturing. It has many advantages in terms of precision, flexibility, production efficiency and cost-effectiveness, and plays an important role in PCB manufacturing in many fields such as high-end electronic products, automotive electronics, industrial control and communication equipment.
The thermal conductivity coefficient is a measure of how well a material conducts heat. It’s represented by the symbol k or λ, and it is measured in units of watts per meter-kelvin (W/m·K). It’s defined as the amount of heat that passes through a material 1 meter thick, with a temperature difference of 1 degree (K or °C) between its two sides, in one second, over an area of 1 square meter.
In general, the higher the thermal conductivity coefficient, the better the material is at transferring heat, so in some high power or power supply electronics, thermal conductivity value is important to transfer heat out. Materials with a high k value, like metals such as copper, allow heat to flow through them easily, which is why they are used in applications that require efficient heat dissipation. In contrast, materials with low thermal conductivity coefficients, such as insulators, are used to minimize heat transfer and preserve energy.
The thermal conductivity is only for the heat transfer form with thermal conductivity. When there are other forms of heat transfer, such as radiation, convection, mass transfer and other forms of heat transfer, the composite heat transfer relationship. The composite heat transfer relationship is often referred to as the apparent thermal conductivity, the dominant thermal conductivity, or the effective thermal transmissivity of material. In addition, the thermal conductivity is for homogeneous materials, in the actual situation, there are also porous, multi-layer, multi-structure, anisotropic materials, the thermal conductivity obtained by this material is actually a comprehensive thermal conductivity performance, also known as the average thermal conductivity.
According to Fourier’s law, the thermal conductivity is defined as
Where x is the direction of heat flow.
qx’’ is the heat flux in this direction in W/m2, and another is the temperature gradient in this direction, expressed in K/m.
For an isotropic material, the thermal conductivity is the same in all directions.
What Is the k Value of Copper?
The thermal conductivity of copper is about 401W/m.K. Copper is a transition element, pure copper is a soft metal, when it is cut on the surface, it is red-orange, and its ductility is good, thermal conductivity is relatively high, so it is a more commonly used material in cables and electronic components, can be used as building materials, and it is composed of many kinds of alloys.
Copper’s high k value meaning it can quickly absorb and distribute heat. That is why copper is used extensively in heat sinks, electrical wiring, and cooling systems. Because of this, it’s highly valued in industries that rely on rapid heat dissipation. Whether in electronics or heavy machinery, the high thermal conductivity of copper ensures that heat does not build up, preventing overheating.
Thermal Conductivity of Common Solid Materials
Here are the thermal conductivity values of some common materials:
Aluminum: 237 W/m·K at 300°C
Copper: 401 W/m·K at 100°C
Iron: 61 W/m·K at 18°C
Steel: 45 W/m·K at 18°C (for carbon steel with 1% carbon)
Silver: 412 W/m·K at 100°C
Graphite: 151 W/m·K at 0°C
These values highlight the differences in heat conduction across materials, with metals like copper and silver being among the most efficient conductors of heat, while materials like steel and graphite have comparatively lower conductivity.
Is Copper a Good Conductor of Heat?
Yes, copper is an exceptionally good conductor of heat. For example, in electronics, copper is often used to cool down processors by transferring heat away quickly, thus ensuring systems run smoothly without overheating. In plumbing, copper pipes help distribute hot water faster, enhancing energy efficiency. From cookware to cooling systems, copper’s outstanding ability to conduct heat makes it indispensable across many fields.
Copper vs. Aluminum PCB: Which is Better?
Both copper and aluminum are excellent conductors of heat in circuit boards manufacturing, but how do they compare? Let’s discuss them from below aspects:
1. Thermal conductivity
First, let’s take a look at the thermal conductivity of aluminum and copper, which is a key indicator of the material’s heat dissipation performance. The higher the thermal conductivity, the better the material’s ability to transfer heat.
Copper: 401W/m.k
Aluminum: 237W/m.k
It can be seen from the data that the thermal conductivity of copper is almost twice that of aluminum, which means that under the same conditions, copper can transfer heat more efficiently. For this reason, copper is often the material of choice in applications that require extremely high thermal performance.
2. Density
Aluminum: Density of about 2.7 g/cm³.
Copper: Density of about 8.96 g/cm³.
Copper is nearly three times as dense as aluminum, which makes copper much heavier than aluminum. In some weight-sensitive applications, such as portable electronic devices, heavy cooling components may affect the portability and user experience of the product. Therefore, in these scenarios, although aluminum is not as conductive as copper, it is still a very popular choice due to its lower weight.
3. Cost
The prices of aluminum materials are low, and processing costs are relatively low. At the same time, aluminum is easy to process into a variety of shapes, which makes aluminum very cost-effective in the manufacturing process. However, the cost of copper is much higher and the manufacturing process is more complex, so the overall cost is much higher than aluminum.
4. Corrosion resistance
Aluminum and copper also have significant differences in corrosion resistance. Aluminum has good oxidation resistance, and the aluminum oxide layer formed on the surface can effectively protect the internal material from further corrosion. However, the corrosion resistance of copper is relatively poor, and it is easy to generate patina (carbonate of copper) in humid environments, which not only affects the appearance but also reduces the heat dissipation performance.
Why Does Copper Have the Highest Thermal and Electrical Conductivity?
Copper’s good thermal conductivity is also related to its internal free electrons. Metal nuclei have a weak ability to bind electrons, allowing free electrons to move freely within the metal and transfer heat rapidly. When one end of a metal is heated, the electrons of atoms or molecules at that end absorb energy and begin to vibrate. These vibrations are passed on to the electrons of neighboring atoms or molecules, forming a heat flow ‌4. Copper is metal-bonded in a way that makes it easier for its electrons to transfer energy inside the metal, and thus heat faster.
Here is the end of this blog sharing, if you have other questions about copper material, welcome to e-mail us: sales@bestpcbs.com.
NRE, or Non-Recurring Engineering, refers to the upfront cost associated with developing and preparing the tools, processes, and engineering resources required for manufacturing a specific product. When it comes to PCB projects, NRE fees are vital because they cover the initial setup expenses that are incurred only once during the product development phase. These charges include design, tooling, programming, and testing requirements tailored to a particular PCB design, ensuring that the production is efficient and meets the required specifications.
Why Is It Necessary to Charge NRE Cost?
Charging an NRE cost is necessary because every PCB project is unique. The manufacturer must allocate resources to tailor the production to your specific design. The NRE fee ensures that all the necessary engineering work is done upfront to avoid delays or errors during mass production. If this fee weren’t charged, manufacturers would have to spread these costs across the entire production, making each unit more expensive, especially for small runs. This way, you can keep per-unit costs lower once production begins.
What Is the NRE Charge For?
The NRE charge is a crucial investment in ensuring that your PCB project gets off to the right start. It covers the engineering resources, setup, and processes that are required to customize the production environment specifically for your PCB design. Here are the main aspects that NRE fees typically cover:
Design Validation
Before manufacturing begins, the manufacturer must confirm that your PCB design is feasible and ready for production. This involves scrutinizing the layout for errors, verifying that it meets performance specifications, and ensuring compatibility with the chosen materials. This step can prevent expensive issues later in the process, such as defective boards or production delays.
Custom Tooling Setup
Every PCB design requires specific tools and fixtures to manufacture efficiently. NRE fees cover the creation or modification of tools that will allow your design to be assembled accurately. This might involve creating custom molds, dies, or specialized equipment that aligns with your PCB’s dimensions and complexity.
Programming and Firmware
For PCBs that require microcontrollers or other programmable components, the NRE charge often includes developing the necessary firmware or software to test and initialize these components. Manufacturers need to upload specific programs to ensure each unit functions correctly in real-world applications.
Prototype Creation
In some cases, the NRE fee also covers the cost of creating prototypes for testing. These prototypes are essential for verifying that the design works as intended before moving into full-scale production. The prototype phase allows for any last-minute adjustments and ensures that the final product will perform optimally.
How to Pay NRE Cost?
Paying the NRE cost is straightforward, but it’s important to clarify this with your manufacturer. Typically, the NRE fee is charged as a separate, one-time payment when you place your order. Depending on your arrangement with the manufacturer, it might be paid upfront or included in the first invoice along with the cost of your first production run. Payment terms can vary, but many manufacturers will expect it before starting the engineering and tooling processes. By paying this fee early, you ensure that your project can begin on time.
How to Reduce NRE Fee?
Reducing NRE costs may not always be possible, but there are ways to minimize them:
1. Reusing designs: If you’ve produced a similar PCB before, you can avoid some NRE costs by reusing or adapting the same designs.
2. Standardization: Using standard components and layouts rather than custom or unusual specifications can cut down on the design and tooling time.
3. Ordering in bulk: A larger production run can sometimes allow manufacturers to absorb some NRE costs, spreading the expense over a larger quantity of units.
4. Simplify design: A less complex design reduces the need for custom tools or special processes, leading to a lower NRE fee.
5. Choose experienced manufacturers: Partnering with a manufacturer like Best Technology who has experience in your industry can reduce the amount of custom setup needed, as they may already have processes and equipment suited to your project.
Considerations During the NRE Process
It’s important to approach the NRE process with a clear understanding of your project’s needs and goals. Communicate clearly with your manufacturer to avoid misunderstandings about what the NRE fee covers. For example, make sure you know if the fee includes changes or revisions to the design after the initial setup. You should also ask about the lead time for the engineering work. Knowing how long it will take to complete the NRE tasks helps you plan your project schedule more effectively.
Another consideration is the long-term benefits. While NRE fees may seem costly upfront, they are an investment that pays off as your project moves into full production. By ensuring that the initial design and setup are correct, you minimize the risk of costly production errors later.
When to Use Non-Recurring Engineering?
Non-Recurring Engineering is most beneficial when your PCB project involves custom designs or complex requirements. This is especially true when you need prototypes, new product development, or designs that require unique tools or processes. If you are producing a PCB that will have ongoing updates or revisions, it might also be necessary to pay an NRE fee each time the design changes. In general, the NRE fee is used whenever a manufacturer has to set up specialized processes or equipment that won’t be reused for other products.
How to Calculate NRE Cost?
NRE costs are calculated based on several factors. Manufacturers will consider the complexity of the design, the number of custom tools needed, and the extent of testing and programming required. The more custom features your PCB has, the higher the NRE cost is likely to be. Additionally, the cost of manpower to design and set up the project is included. Some manufacturers also calculate NRE based on the projected production run—larger runs may benefit from lower NRE fees as costs are spread over more units.
While it may seem daunting, NRE costs are ultimately a necessary investment for ensuring the success of your project. They allow manufacturers to deliver the best quality and avoid production errors, which can lead to greater savings in the long run.
