PCB Tech - Understand what BGA refers to in PCBA processing

In daily PCBA processing, the full name of BGA is Ball Grid Array (solder ball array package), which is to make an array of 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). The device packaged with this technology is a surface mount device. It is a packaging method in which an integrated circuit adopts an organic carrier board. In order to be able to determine and control the quality of such a process, it is required to understand and test the physical factors that affect its long-term reliability, such as the amount of solder, the positioning of wires and pads, and wettability. The performance and assembly of BGA devices are superior to conventional components, but many manufacturers are still unwilling to invest in the ability to develop mass production of BGA devices. The main reason is that it is very difficult to test the solder joints of BGA devices, and it is not easy to guarantee its quality and reliability.

In the current information age, with the rapid development of the electronics industry, products such as computers and mobile phones have become increasingly popular. People have more and more functional requirements and stronger performance requirements for electronic products, but the volume requirements are getting smaller and the weight requirements are getting lighter and lighter. This has promoted the development of electronic products in the direction of multi-function, security, miniaturization and light weight. In order to achieve this goal, the feature size of IC chips will become smaller and smaller, and the complexity will continue to increase. As a result, the number of I/Os in the circuit will increase, and the I/O density of the package will continue to increase. In order to meet the requirements of this development, some *high-density packaging technologies have emerged, and BGA packaging technology is one of them.

BGA packaging appeared in the early 1990s and has now developed into a mature high-density packaging technology. Among all packaging types of semiconductor ICs, BGA packaging grew the fastest during the five-year period from 1996 to 2001. In 1999, the output of BGA was about 1 billion. However, so far, this technology is most suitable for high-density, high-density device packaging, and the technology is still developing in the direction of fine pitch and high I/O terminal count. BGA packaging technology is mainly suitable for the packaging of PC chipsets, microprocessors/controllers, ASICs, gate arrays, memories, DSPs, PDAs, PLDs and other devices.

Features of BGA package in PCBA processing:

1. Less packaging area;

2. The function is increased, and the number of pins is increased;

3. The PCB board can be self-centered during melting and soldering, and it is easy to be tinned;

4. High reliability, good electrical performance and low overall cost.

PCBA-processed PCB boards with BGA generally have many small holes. Most customers’ BGA vias are designed with a finished hole diameter of 8-12 mils. The distance between the surface of the BGA and the hole is 31.5 mils as an example, generally not less than 10.5 mils . BGA via holes need to be plugged, BGA pads are not allowed to be filled with ink, and BGA pads are not drilled.

In PCBA processing, BGA devices can consistently achieve a defect rate of less than 20 (PPM) when using conventional SMT process procedures and equipment for assembly production. Since the beginning of the 1990s, SMT technology has entered a mature stage. However, with the rapid development of electronic products in the direction of convenient/miniaturization, networking and multimedia, higher requirements have been put forward for electronic assembly technology. Density assembly technologies continue to emerge, among which BGA (Ball Grid Array package) is a high-density assembly technology that has entered the practical stage.