BGAs What They Are & When to Use Them-Hitech PCB

The ball grid array (BGA) is a surface-mount chip package that is used to mount embedded devices (e.g. microprocessors) by melting balls of solder between the face of the device and the circuit board.

Unlike the perimeter-only package type, which place soldering pins along the edge of the device, a BGA aligns its solder balls in a grid beneath the bottom surface of the device. As a result, this approach leaves a considerably smaller footprint on the PCB and induces better thermal and electrical properties than a perimeter-style mounting package.

It’s no surprise the format’s popularity has grown in tandem with the continuous miniaturization of electronics.

Bonding a device’s BGA with the copper trace pads on a PCB requires the use of either a reflow oven or infrared heating. These tools produce an even distribution of heat that melts each solder ball individually, effectively keeping the package aligned with pre-defined alignment indicators (pads) while the solder solidifies and forms the actual connection between the embedded device and the board.

The main disadvantage attributed with BGA usage is that soldering connections cannot be visually inspected once the device is mounted. The only way to test the BGA and eliminate the possibility of a soldering fault is through the use of X-ray machines, or such solutions. Poorly soldered BGAs can be removed and salvaged at a rework station, where they are replaced with new packets of solder balls, but repeated refurbishing will diminish the life expectancy of the embedded device to which they are attached.