Rework and hand soldering of BGA Packages is the toughest part. It needs practice to do the job. Let us understand Desoldering and soldering of BGA packages:
The most common practice to desolder BGA is hot air. Here are the steps to desolder BGA Package using Hot Air:
Apply liquid solder flux on the sides of the package.
Preheat the package from both top and bottom. Heat can be given from the bottom using a preheated while heat from the top can be given using a Hot Air Rework System. Hakko FR-820 is the best available preheater while Hakko FR-803 is the best economical Hot Air SMD / BGA Rework System
Now using the correct BGA Nozzle, give heat on top of the BGA Package.
The solder balls underneath the BGA package will melt. Pick up the package with a Tweezer of using vacuum pick-up.
Again the most common practice to solder BGA is hot air. Here are the steps to solder BGA Package using Hot Air:
Once the BGA Package is removed, clean the pad and remove any excess solder from the board.
Apply Flux Paste (Not Liquid Flux) on to the pad. Paste flux will help solder balls to stick so that they do not fall or change position.
Place solder balls very carefully on the pad.
Apply paste flux to the bottom (soldering side) of the BGA package.
Carefully place the BGA Package of the solder balls.
Preheat and then apply Hot Air from both top and bottom.
Solder balls will melt and get soldered.
BGA technology and the BGA soldering is very reliable if done using the correct procedure. A BGA has less resistance to heat and hence there is lesser or no damage due to overheating.