BGA Assembly: Optimizing Space, Strength, and Soldering in PCB Design

BGA assembly by definition relates to the process of placement of ball grid arrays on a PCB through the use of the solder reflow method. They are surface mount components that employ solder ball arrays to form interconnection. It is the solder balls that melt and form interconnection when the board is taken for the solder reflow oven.

What do want as benefits or pros to a BGA assembly?

It provides enhanced electrical and thermal performance and at the same time optimizes the utilization of space.

Strengthens the structure and at the same time decreases the overall thickness of the board.

It reduces the possibility of having PCB damage because BGA leads are made from solid solder balls hence cutting down on maintenance and repair time.

Designed for packages that have a small area and many pins.

It presents enhanced solderability so that the assembly process can be completed within less time.

This is because they possess low thermal resistance meaning that they dissipate heat rapidly.

What measures should be taken to propagate good soldering while undertaking BGA assembly?

Enough heat should be applied so that all the balls in the grid melt to achieve good wetting or actual bond for every BGA solder joint.

The surface tension of molten balls anchored the BGA package down until the solder became rigid. The soldering process must therefore be carried out under an appropriate temperature to enable the formation of proper solder joints. It also helps to avoid the solder balls shorting with one another as illustrated below.

The choice of solder alloy and the soldering temperature it is subjected to is always made in such a manner that while melting is never full, the solder remains somewhat molten. It facilitates so that each ball should not touch the neighboring ball. It is always recommended that one should always stick to the reflow temperature profile provided by the component manufacturer.

Exploring what it means to assess solder joint quality?

Optical-based methods can also be used to inspect ball grid arrays since most of the solder joints are obscured by the BGA parts. Also, electrical tests are not that efficient because what the test shows is the electrical conductivity of the BGA at a certain point in time. The kind of tests that can be carried out on the soldering does not enable one to determine whether the solder will be long-lasting or not. This solder joint may however fail after some time.

X-ray is one of the testing methods for inspecting the BGA assembly solder joint while electrical tests are used in testing the electrical functionality of the product. One gets the benefit of looking through the solder joint below the BGAs. Because of this advantage, AXI, an automated X-ray inspection technique is preferred in the inspection of BGA.