BGA repair, also known as ball grid array repair, is one of the most challenging procedures performed in assembly facilities and repair stations around the world. To perform repair correctly, technicians must possess the necessary repair skills and relevant knowledge and experience. This is because various issues are encountered during the BGA repair process. Here are some common problems that occur during BGA chip rework.
This problem is usually caused by incorrect use of solder paste or process parameter settings, which can damage the integrity of the chip device and require additional rework or cause device damage if the void is greater than 25%. Pad damage during BGA reballing is inevitable, and sometimes the use of conformal coating and bottom fillers may not be effective. How to prevent damage to the BGA during repair is the main control issue during repair. Incorrect BGA orientation or joint bridging. This means extra rework thermal cycling, and increased damage risk with each successive heat application.
Technicians who perform BGA repair with BGA rework machines must undergo sufficient training, as their skill practice and operational proficiency directly affect the repair yield. Staff must be aware of the materials, tools, process steps, and the interrelationships of all factors they are using when using repair equipment.
You need the right tools to work properly and improve repair yields. Many people do not choose appropriate repair equipment when choosing to purchase repair equipment, which will reduce the success rate of repairs. The equipment used for BGA machine rework must have ease of operation, flexibility, and safety.
The first thermal cycle is applied before the BGA rework site, and if this process is to be performed correctly, a lot of preparatory work is required. This includes baking moisture from BGA equipment and circuit board components to prevent "bursting" and other issues, as well as removing or protecting nearby thermally sensitive components to avoid damage or inadvertent reflux. Correct decisions need to be made in advance, such as whether to use solder paste, select the correct solder paste template, and choose appropriate chemicals and alloys.
Before the actual rework cycle begins, there are many preparatory works. This includes accurate evaluation of solder ball size; co-planarity of the device and its balls; mask damage, PCB location loss or contamination.
There are also issues to consider, such as reflux causing oxidation, dehydration, pad and lead damage, core absorption, starvation joints, component damage, and other problems that may generate a large number of new rework issues. During the repair process, it is also necessary to consider whether excessively high temperatures will affect other components adjacent to the component on both sides. The goal is to minimize the effects of heat migration outside of BGA rework machine reprocessing, which is a controlled process of perfecting the rework step.
BGA components are becoming smaller and smaller. The biggest problem currently faced is how to accurately find the problem in the chip and quickly use repair tools to repair the chip.