Posts Tagged ‘BGA’

Friday, August 30th, 2024

Ball grid array (BGA) is a surface mount package for integrated circuits. Its ability to accommodate a large number of pins while maintaining a small footprint makes it ideal for modern electronic devices with limited space. BGA packages are used in a variety of applications, from consumer electronics such as smartphones and laptops to industrial equipment and automotive systems.

What is BGA?

Ball grid array (BGA) is a common surface mount package that is derived from pin grid array (PGA) technology. It uses a grid of solder balls or leads to conduct electrical signals from the integrated circuit board. Instead of using pins like PGA, BGA uses solder balls placed on a printed circuit board (PCB). By using conductive printed wires, PCBs support and connect electronic components.

Unlike PGA, which has hundreds of pins and is difficult to solder, BGA solder balls can be evenly distributed without accidentally connecting them together. Solder balls are first placed in a grid pattern on the bottom of the package and then heated. By using surface tension when melting the solder balls, the package can be aligned with the circuit board. The solder balls cool and solidify, with accurate and consistent distances between each other.

What does a BGA do?

The main role of BGA (Ball Grid Array) packaging technology includes providing high-density, high-performance packaging solutions for microprocessors, ASICs, DSPs, PDAs, PLDs and other devices. This technology achieves surface mounting by making array solder balls on the bottom of the package substrate as the I/O end of the circuit to interconnect with the printed circuit board (PCB).

BGA packaging technology is small, light, and high-performance. It can provide more pins than other packaging technologies such as dual in-line package (DIP) or quad flat package (QFP). The entire bottom surface of the device can be used as pins instead of only the periphery.

This allows BGA packages to have shorter average wire lengths than periphery-limited package types, thereby providing better high-speed performance.

The advantages of BGA packaging are not only its high density and high performance, but also its less stringent requirements for welding accuracy. Even during the soldering reflow process, even if the solder ball is offset from the pad, the device position can be automatically corrected due to the surface tension of the solder.

What are the disadvantages of BGA?

The disadvantages of BGA packaging technology mainly include difficulty in detection, high difficulty in repair, relatively high production cost, stricter requirements on the reliability of solder joints, and sensitivity to temperature and humidity. ‌

1. Difficulty in detection: Since the solder ball is located at the bottom of the chip, the traditional optical inspection method cannot effectively detect the welding quality, and X-ray detection and other equipment must be used, which increases the cost and time of detection. ‌

2. High difficulty in repair: If there is a welding problem, the BGA packaged device needs to be disassembled and reassembled. This process has high technical requirements and certain risks. ‌

3. Relatively high production cost: Compared with QFP packaging, BGA packaging has higher material, production and inspection costs. ‌

4. More stringent requirements on the reliability of solder joints: Due to its small size, the BGA packaging method has very high requirements on solder joints. If there are problems such as empty solder joints and cold solder joints in the solder joints, the BGA package will fail.

5. Sensitive to temperature and humidity: BGA packaged components are very sensitive to temperature and humidity and need to be stored under constant temperature and dry conditions.

These shortcomings have limited the widespread application of BGA packaging technology to a certain extent, especially in application scenarios with high requirements for cost, reliability and environmental adaptability.

How is BGA made?

The production process of BGA (ball grid array package) mainly includes several key steps, which ensure the high quality and high reliability of BGA package. ‌

1. Wire bonding PBGA packaging process flow:

Substrate preparation: extremely thin copper foil is laminated on both sides of the BT resin/glass core board, and then drilling and through-hole metallization are performed.

‌Graphic production: Use conventional PCB processing technology to make graphics on both sides of the substrate.

‌Solder mask production: Add solder mask and make graphics to expose electrodes and welding areas to improve production efficiency. A substrate usually contains multiple PBGA substrates.

2. ‌BGA area via plugging‌:

The vias in the BGA pad area generally need to be plugged to prevent foreign matter in the hole or to protect the service life of the via, and to prevent the via from tinning during the reflow soldering of the SMT patch, causing a short circuit on the other side.

3. ‌Via in the plate, HDI design‌:

For BGA chips with small pin spacing, when the pin pad cannot be connected due to the process, it is recommended to directly design the via in the plate, and use the HDI blind buried hole wiring method to design the PCB, punch the via in the plate on the BGA pad, punch the buried hole in the inner layer, and conduct the wiring in the inner layer.

4. ‌BGA welding process‌:

‌Printing solder paste‌: Apply an appropriate amount of solder paste evenly on the PCB pad to ensure that the patch components and the corresponding pads on the PCB achieve good electrical connection and sufficient mechanical strength during reflow soldering.

‌Device placement‌: Use a placement machine to accurately mount the chip components to the corresponding position on the PCB surface printed with solder paste or patch glue.

5. Special size design and automated production:

BGA features include high pinhole density, easy automated production, high reliability, and the ability to design special sizes to achieve a more compact chip layout.

What is the difference between PCB and BGA?

The main differences between PCB and BGA are their structure, function, and application scenarios. ‌

1. Structure:

PCB (printed circuit board) is a basic electronic component that provides an electrical connection path between components. BGA (ball grid array package) is an advanced packaging method that connects components to PCB through a spherical pad array, with the advantages of high density and high reliability.

The pins of BGA are spherical and are generally directly soldered on the PCB board. Desoldering requires a special BGA rework station, and individuals cannot desolder; while the pins of PGA (pin grid array package) are pin-shaped. When installing, the PGA can be inserted into a special PGA socket for easy disassembly.

2. Functions and application scenarios:

BGA packaging effectively uses PCB space, which helps save enough space for customization in PCB and improve its efficacy. The size of BGA package is very small, so these PCBs have less heat dissipation and are easy to achieve the dissipation process.

There are no bendable or fragile pins in BGA package, so the durability of these PCBs is increased, and good electrical performance is also ensured. The pads of BGA package are large enough to make it easy to solder and easy to operate, so easy soldering and handling make it very fast to manufacture.

In summary, BGA, as an advanced packaging technology, has been widely used in high-performance electronic products through its unique ball grid array structure and high density and high reliability characteristics. Traditional PCBs provide basic electrical connection paths and are the basic components of electronic devices.

How many types of BGA are there?

There are many types of BGA, mainly including:

1. PBGA (plastic package BGA): This is the most commonly used BGA packaging form, made of plastic materials and plastic processes.

2. CBGA (ceramic BGA): This packaging type uses a multi-layer substrate with precious metal interconnect circuits.

3. CCGA (ceramic solder column array)

4. TBGA (BGA with tape)

5. MBGA (metal BGA)

6. FCBGA (flip chip BGA)

7. EBGA (BGA with heat sink)

In addition, BGA can be divided into staggered type, full array type, and peripheral type according to the arrangement of solder balls.

Conclusion:

Ball grid array (BGA) packaging is a key technology in modern electronic products. It makes it possible to develop more powerful and compact devices. BGA has become the first choice for applications that require high performance, reliability and miniaturization.

BGA packaging is famous for its advanced packaging technology. BEST Technology is recognized as the most trusted one-stop electronic circuit solution provider in the world, and BGA production is one of its most important projects. We specialize in the production and assembly of PCBs containing BGA packaging.

What is BGA Soldering?

BGA soldering is a technique that involves the attachment of integrated circuit packages to a PCB using an array of solder balls. These solder balls are typically made of lead-based or lead-free alloys, depending on environmental regulations and specific requirements. The BGA package consists of a substrate, which acts as a carrier for the integrated circuit, and the solder balls that form the electrical and mechanical connections between the package and the PCB.

The Importance of BGA Soldering in Electronics Manufacturing

BGA soldering plays a critical role in the manufacturing of various electronic devices such as computers, smartphones, and gaming consoles. The increased demand for smaller and more powerful electronics has driven the adoption of BGA packages. Their compact size and high pin density make them suitable for advanced applications where space is limited.

Challenges Faced in BGA Soldering

Component Alignment and Placement

One of the primary challenges in BGA soldering is ensuring accurate component alignment and placement on the PCB. The small size of the solder balls and the dense layout of the BGA package make it difficult to achieve precise positioning. Misalignment during the assembly process can result in solder bridges, open connections, or mechanical stress on the package.

To address this challenge, manufacturers employ advanced technologies such as Automated Optical Inspection (AOI) and X-ray Inspection. AOI systems use cameras and image processing algorithms to verify the correct alignment and placement of BGA components. X-ray inspection, on the other hand, allows manufacturers to see beneath the surface of the PCB and detect any misalignment or defects that may not be visible to the naked eye.

Solder Paste Application

Another significant challenge in BGA soldering is achieving precise and consistent solder paste application. Solder paste, a mixture of solder alloy and flux, is applied to the PCB pads before placing the BGA package. Inadequate or excessive solder paste can lead to solder defects such as insufficient solder joints, solder voids, or solder bridging.

To overcome this challenge, careful attention must be given to stencil design and aperture selection. Stencils with appropriate thickness and properly sized apertures ensure accurate solder paste deposition. Additionally, manufacturers can employ Solder Paste Inspection (SPI) systems to verify the quality and consistency of the solder paste applied. The solder paste that Best Technology uses is SAC305 solder paste, which has good printability and excellent stability.

Temperature Profiling

Temperature profiling, or we can say the thermal management, it is crucial in BGA soldering to ensure proper reflow of the solder paste. The reflow process involves subjecting the PCB to a carefully controlled temperature profile, allowing the solder paste to melt, form a reliable joint, and solidify. Inadequate temperature profiling can lead to insufficient solder wetting, incomplete reflow, or thermal damage to components.

Manufacturers must optimize the reflow oven setup and calibration to achieve the correct temperature profile. Thermal profiling techniques, such as the use of thermocouples and data loggers, help monitor and control the temperature during the reflow process.

Reflow Process

The reflow process itself presents challenges in BGA soldering. The soak zone, ramp rates, and peak temperature must be carefully controlled to prevent thermal stress on the components and ensure proper solder reflow. Inadequate temperature control or improper ramp rates can result in solder defects such as tombstoning, component warpage, or voids in the solder joints.

Manufacturers need to consider the specific requirements of the BGA package and follow recommended reflow profiles provided by component suppliers. Proper cooling after reflow is also essential to prevent thermal shock and ensure the stability of the solder joints.

Inspection and Quality Control

Inspection and quality control are critical aspects of BGA soldering to ensure the reliability and performance of the solder joints. Automated Optical Inspection (AOI) systems and X-ray inspection are commonly used to detect defects such as misalignment, insufficient solder wetting, solder bridging, or voids in the solder joints.

In addition to visual inspection techniques, some manufacturers may perform cross-section analysis, where a sample solder joint is cut and examined under a microscope. This analysis provides valuable information about the quality of the solder joint, such as solder wetting, void formation, or the presence of intermetallic compounds.

In a word, BGA soldering presents unique challenges in electronics manufacturing, primarily related to various factors. By addressing these challenges effectively, manufacturers can ensure the reliability and performance of BGA solder joints, contributing to the production of high-quality electronic devices. Best Technology has rich experience in PCBA assembly and we mounted thousands PCBs for our customers, whatever it is simple design or complex design, all the products are assemble perfect and work well in customer side. Please feel free to contact us for any questions about PCBA.