The importance of BGA in PCB assembly

The importance of a correct PCB layout cannot be overemphasized. When it connects various electronic components on a single substrate, the stability and efficiency can be greatly affected by attaching the components to the surface of the board. So far, pin grid array (commonly known as PGA) is the standard to package integrated circuits on board. However, it has been replaced by a ball grid array or BGA design. In short, although the PGA uses a square array of pins to mount the components, the BGA replaces the pins with metal balls made of solder, which are attached to the bottom of the device.

This article will introduce BGA to you from the following points: advantages of using BGA, other BGA types used in different situations

(1) Advantages of using BGA

1. low line density - the metal welding balls are arranged in a grid shape. The orbital density can be greatly reduced. This, in turn, means an optimized PCB layout because the tightness of the ball improves efficiency. Trying to perform the same operation on the pin grid array by increasing the number of pins increases the risk of accidental bridging. However, for BGA and solder ball, bridging is not a big problem.

2. reduce the chance of component damage - the needle grid array requires welding processes to potentially damage the assembly. On the other hand, with BGA, only the solder balls need to be heated to melt and adhere to the PCB. Therefore, the possibility of any component damage is greatly reduced. Moreover, the surface tension between the ball and the circuit board ensures that the package is held in place.

3. reliability - when using PGA, the fragility of pins is always a problem. They need extra care and are prone to bending and damage. The system is more robust and reliable by using BGA connected to pad of solder ball

4. improved performance - due to grid arrays, the BGA internal connection is shorter. It means to reduce the lead sensing level, which usually improves performance at higher speeds.

5. reduce the possibility of overheating - the decrease of heat resistance between BGA and circuit board is a major advantage. In fact, because the BGA unit provides a hot channel to guide the heat, the heat generated is dissipated to the circuit board.

(2) Other BGA types used in different situations

The ball grid array, or MAPBGA, is an ideal choice for low-cost, medium and low-performance devices. Heat dissipation enhanced plastic ball grid array or TEPBGA, this package can provide higher heat dissipation level. Tape ball grid array or TBGA, which is the ideal choice for high-end solutions. Encapsulated on a package or pop, which allows storage packages to be stacked on top of the base device, so it's useful for applications where space is actually limited.

In general, the BGA welding process is very good, but there are many unique welding problems, which are mainly related to the BGA packaging structure, especially the thin FCBGA and PBGA. Due to the layered structure of the packaging, deformation will occur in the welding process. Generally speaking, this kind of deformation in the welding process is called dynamic deformation, which is the main reason for many bad BGA assemblies.