BGA Rework Process Introduction
1 Introduction
Defects are caused by many reasons during soldering SMD components as empty soldering, short circuit and others, so repair is necessary. The rework process is simple for common SMD, resistor, capacitor, SOIC, SOJ, PLCC and others. With small alignment are more and more in electronic products, lots of BGA, CSP, QFP and others are more and more, so rework stations become good helpers for operators.
2 How to Choose Rework Station
Main differences of rework stations are heat source and heat mode; Take example only upper heat or upper and lower both heating, some can set temperature curve. Considering protecting components, the upper and lower both heating system are better. To prevent PCB warping during repairing, preheat function in the rework system is better. PCB fix, BGA position and others are important consideration.
3 Rework process
1) BGA disassemble
Remove BGA chip with rework system and clean solder residue on PCB with solder iron to make solder pad flat; clean and remove flux residue with special cleaner.
2) BGA dry
Please check all BGA chips dry or damp; put damp BGA components into dry box to dry.
3) Print solder paste
Print solder paste on disassemble location before soldering BGA; small and special BGA stencil is necessary because there are other components on the board; Thickness and size of stencils are decided by BGA ball diameter and distance.
For CSP whose ball diameter is <0.4mm, operators can cover flux on PCB solder pad directly.
4) Mount BGA chips
Set rework program and put dry BGA into preparation location; rework system will take it automatically and then place it into soldering location.
5) Solder
Set soldering temperature according BGA size, PCB thickness and others; then rework station will complete soldering process.
Take BGA400 rework station from Beijing Glichn as example, more support is from Beijing Glichn S&T Development Co.,Ltd. www.smtchn.com.

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