Fumax

PCB assembly engineer explains BGA assembly process

The BGA assembly process is a complex technology in the PCB assembly process that requires following a series of strict steps and rules.

PCBA engineers will introduce to you in detail what BGA is?

The full name of BGA is Ball Grid Array (PCB with ball grid array structure). It is a packaging method in which integrated circuits use organic carrier boards. The characteristics of BGA include reduced packaging area, increased functions, increased number of pins, self-centering of PCB boards during soldering, easy soldering, high reliability, good electrical performance, and low overall cost.
PCB boards with BGA generally have more small holes. Most customers’ BGA via holes are designed to have a finished hole diameter of 8 to 12 mil. The distance from the surface of the BGA to the hole is 31.5 mil, for example, and is generally not less than 10.5 mil. The vias under the BGA need to be plugged, ink is not allowed on the BGA pad, and no holes are drilled on the BGA pad.

BGA is a high-density surface mount packaging technology. On the bottom of the package, the pins are ball-shaped and arranged in a grid-like pattern, hence the name BGA.

Advantages and Disadvantages of BGA in PCB Assembly

Advantages of BGA include:

1. Reduction in packaging area: Since the BGA uses spherical pins, the packaging area can be greatly reduced and space utilization is improved.
2. Increased number of pins: BGA has more pins than traditional chip packaging technology and can provide more connection points, making the connection between the chip and external circuits closer.
3. High reliability: The BGA packaging method makes the chip less susceptible to damage during the welding process, improving the reliability of the packaging.
4. Good electrical performance: The ball-shaped pins of BGA can better connect with the PCB board, making the signal transmission more stable and the electrical performance better.
5. Low overall cost: Although the manufacturing cost of BGA is slightly higher than traditional packaging technology, due to its high reliability, good electrical performance and other advantages, it reduces the overall cost of electronic equipment.

Disadvantages of BGA include:

1. Difficulty in maintenance: Due to the packaging method of BGA, the chip is difficult to disassemble and replace. Once damaged, the entire circuit board needs to be replaced, and the maintenance cost is high.
2. High welding requirements: The welding of BGA requires the use of special equipment and processes, and the welding requirements are high. Improper welding can easily lead to a decrease in electrical performance.

In summary, BGA is a high-density surface mount packaging technology that has many advantages, but also some disadvantages. PCB engineers need to select appropriate packaging technology based on actual conditions and strictly control the welding process to ensure the performance and reliability of electronic equipment.

General rules for BGA pad design in PCB assembly

General rules for BGA pad design include:

1. Pad diameter: Pad diameter can affect both the reliability of solder joints and the wiring of components. The pad diameter is usually smaller than the solder ball diameter. In order to obtain reliable adhesion, it is generally reduced by 20% to 25%. The larger the pad, the smaller the wiring space between the two pads.
2. Wiring between pads: The calculation of the number of wirings between two pads is P-D≥(2N+I)Xr, where P is the solder ball spacing, D is the pad diameter, N is the number of wirings, and X is the line width.
3. Wire width: The width of the wire connected to the pad should be consistent, generally 0.15~0.2mm.
4. Solder mask size: The solder mask size is 0.1~0.15mm larger than the pad size.
5. CBGA pad design: It is necessary to ensure that the template opening allows the amount of solder paste leakage to be greater than or equal to 0.08mm^3 (this is the minimum requirement) to ensure the reliability of the solder joints after the PCBA processed products are produced. Therefore, the pad of CBGA is larger than that of PBGA.
6. Outer frame positioning line: Setting the outer positioning line is very important for post-SMT inspection.

The above rules are for reference only. It is recommended to consult the official information on BGA pad design in PCB assembly for more accurate information.

What are the basic principles of BGA pad design?

The basic principles of BGA pad design include the following points:

1. The center of the solder pad matches the center of the corresponding solder ball on the bottom of the BGA.
2. The PCB pad pattern is a solid circle, and via holes cannot be processed on the pad.
3. The width of the wire connected to the solder pad should be consistent, generally 0.15mm~0.2mm.
4. The solder resist size is 0.1mm~0.15mm larger than the pad size.
5. After metallization, the via hole near the solder pad must be blocked with solder resist, and the height must not exceed the height of the solder pad.
6. Process the screen pattern on the four corners of the BGA device. The line width of the screen pattern is 0.2mm~0.25mm.
7. The pad shape of BGA devices is circular, and usually the PBGA pad diameter should be 20% smaller than the solder ball diameter.
8. The spacing between the pads should be designed in metric. Since the component manual will give two dimensions: metric and inch, in fact the components are produced in metric. Designing the pads in inch will cause installation deviation.

The above BGA pad design principles are for reference only. It is recommended to check the official information on BGA pad design, or contact us, we provide professional technical support services.

Fumax is a factory specializing in the processing of various electronic products, providing SMT patch processing, SMD processing, BGA, FPC, soft board, flexible circuit board SMT patch processing, DIP plug-in processing and post-welding processing, PCB assembly and testing processing, etc. Serve.

Which BGA assembly company is the best in Shenzhen, China?

Fumax is a high-tech enterprise engaged in electronic product project development, PCB welding, and OEM assembly production. The company mainly provides various electronic design, manufacturing, and assembly services, including motor controller PCB assembly, smart home electronic design, LED PCB assembly design, etc. .