Posts Tagged ‘PCB technology’

What is laser direct imaging technology?

Wednesday, October 9th, 2024

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.

What is Stamp Hole on PCB and its Purpose?

Stamp holes, also sometimes called breakaway holes or mouse bites, are small holes drilled in a row or array along the rails or edges of each circuit board within the panel. They look like the edges of a stamp, so people call it “stamp holes”.

Stamp hole is used primarily in the process of depanelized PCBs. De-paneling is the process of separating individual PCBs from a larger panel, which is a common method in PCB manufacturing to improve production efficiency and reduce costs. The larger panel makes handling and processing multiple PCBs easier during the manufacturing process. In some ways, panel also improves the utilization of the raw materials. Once the manufacturing steps are complete, the individual PCBs need to be separated for use in their corresponding devices. And these holes between the single PCBs can create a weak point along which the boards can be easily broken apart after manufacturing be completed.

Why Use Stamp Holes Expertise In PCBs?

It is possible to use stamp holes if the boards are abnormal shaped or round. The stamp hole is connected between each circuit boards, which mainly plays a supporting role and avoid PCB be scattered. Most commonly, they are used to create PCB stand-alone modules, such as Wi-Fi, Bluetooth, or core board modules, which are then used as stand-alone components placed on another board during PCB assembly.

The use of stamp holes allows for a relatively clean break along the separation line, but it may leave behind rough edges or require additional finishing steps to smooth out the remnants of the perforation points. This method of depaneling is a cost-effective solution and can be used for various types of PCBs, but it might not be suitable for very delicate circuits or when a perfectly smooth edge is required. In addition, V-cut and hollow connection strips also are the common depaneling ways for PCBs.

What are differences between Stamp Hole, V-cut and Hollow strip?

When preparing a panel for the manufacturing of multilayer PCBs, it’s essential to consider a method used to connect individual boards within the panel. As mentioned above, there are three connection methods for PCB technology, each serving different types of PCB designs and requirements. So, which one is the better or how to choose a suitable one for your project? Welcome to keep reading.

V-Cut (V-slot)

V-cut is the most common way to separate the PCBs during the circuit board manufacturing. It mainly utilizes for PCBs with straight edges or straight lines. This method involves cutting a V-shaped groove along the line where two PCBs are connected within the panel. When implemented, V-cuts leave a narrow gap (the width of the V-cut itself) between the boards. V-cut depth is an essential point during the process, make sure it has 1/3 depth on top and bottom side. The V-cut is especially suitable for standard, rectangular PCB designs, allowing for a clean and efficient separation of the boards once all other manufacturing processes have been completed.

Stamp Holes

For PCBs with unique or irregular shapes, stamp holes are often the preferred method of connection. Its process involves drilling multiple small holes in an array at the points where the individual PCBs connect within the panel. These holes create a perforated line that weakens the material enough to facilitate easy separation of the boards by applying minimal force, without compromising the integrity of the circuitry. But this way can only be used if you don’t have strict requirements for burrs on edges. And it is easy to damage the whole board if use improper approach.

Hollow Connecting Strips

Hollow connecting strips are used in scenarios where a very narrow strip of material is left to connect the boards within the panel. This method is particularly useful for PCBs utilizing half-hole (castellated holes) technology. The narrow strips maintain the alignment and integrity of the PCBs during the manufacturing process but can be easily removed or broken away to separate the individual boards. Hollow strip is less common but essential for specific designs and technologies.

Each of these connection methods has its specific applications, advantages, and considerations. The choice between V-cuts, stamp holes, and hollow connecting strips depends on the design of the PCB, the requirements of the manufacturing process, and the desired ease of separation post-manufacturing.

How to Add Stamp Holes on Your Circuit Board?

Designing stamp holes is a critical step in preparing your PCB for the depaneling process. This includes creating a series of small holes along the intended lines of separation between individual boards in a panel. Here’s a step-by-step guide to help you incorporate stamp holes into your PCB design effectively:

1. Understand the Purpose

Recognize that stamp holes are used to facilitate the manual separation of PCBs from a panel after the manufacturing process, minimizing the risk of damage to the board and its components.

2. Plan Your Layout

Placement: Decide where the stamp holes will be located on your PCB layout. They should be placed along the edges where the PCB will be separated from the panel.

Number and Spacing: The number of stamp holes and their spacing can significantly affect the ease of PCB separation. Typically, a distance of 0.5mm between holes and 1.0mm between centers of holes are used, but this may vary based on the PCB material and thickness.

3. Select the Hole Size and Quantity

The diameter of stamp holes usually ranges from 0.6 mm to 1 mm. The size may depend on your specific requirements and the capabilities of your PCB manufacturer. As for quantity, 5-8 holes in an array is good (always 2 arrays/rows), more also is available, it can be adapted based on your specific needs.

4. Arrangement of Stamp Holes

Two rows of stamp holes should be added at the edge of the PCB, extending slightly into the board. This design ensures that any burrs left on the board edge after separation will not affect the PCB’s overall dimensions. If there are traces or other critical components on the edge of the board, ensure that the stamp holes are placed to avoid damaging these elements during separation.

5. Design Using PCB Design Software

Use your PCB design software (such as Altium Designer, Eagle, or KiCad) to add the stamp holes to your design. This can usually be done by placing a series of via or pad holes along the separation lines.

Some software packages may offer tools to automate this process, allowing you to specify the number of holes, their spacing, and diameter, and then automatically place them along a line.

6. Consult with Your Manufacturer

Before finalizing your design, consult with your PCB manufacturer for any specific guidelines or requirements they have for stamp holes. This can include preferred sizes, spacing, and any additional considerations to ensure the depaneling process goes smoothly.

Provide detailed documentation of your stamp hole design to your manufacturer to avoid any confusion during the production process.

7. Review and Adjust

After adding the stamp holes to your design, review the layout to ensure that there is adequate clearance between the holes and any nearby components or traces. This is crucial to avoid damage during the separation process.

Adjust the size, spacing, and number of stamp holes as necessary to meet both your design requirements and the manufacturer’s capabilities.

In the design process, these considerations should be adjusted based on the specific PCB design and manufacturing requirements. Moreover, find a reliable PCB manufacturer to ensure these design details are accurately implemented is key to successfully fabrication.

Best Technology specializes in PCB manufacturing for more than 17 years, offering comprehensive PCB production and design services to over 200 countries worldwide. To ensure the best quality and fast delivery, we set up a strictly quality control system according to ISO9001 and equipped with advanced measured devices such as AOI, X-RAY, 2D, 3D measurement tools in our factory. We provide 24/7 hours service and commitment with a timely reply within 10 hours. We sincerely appreciate your any comments or consults, welcome to contact us at any time.