Traditional BGA rework process

Traditional BGA rework process involves several steps. Here’s the process:

1. BGA Removal: Using a soldering iron, remove the residual solder from the PCB pads, ensuring they are clean and flat. Specialized tools like desoldering braid and flat soldering iron tips can be used for cleaning. Take care not to damage the pads or solder mask. Clean the flux residue using a dedicated cleaning agent.
2. Dehumidification: BGA components are sensitive to moisture, so it’s essential to check for moisture before assembly. Dehumidify any components that have been exposed to moisture.
3. Solder Paste Printing: Use a BGA-specific stencil to apply solder paste. The thickness and opening size of the stencil should match the ball diameter and pitch. After printing, inspect the quality of the solder paste. If it’s not up to standard, clean the PCB thoroughly and let it dry before reprinting. For CSPs with a pitch below 0.4mm, solder paste printing may not be necessary, and instead, solder paste can be applied directly to the PCB pads.
4. Component Removal: Place the PCB with the component to be removed into the reflow oven and start the reflow process according to the set program. When the temperature reaches its peak, use a vacuum pen to remove the component. Allow the PCB to cool.
5. Solder Pad Cleaning: Use a soldering iron to clean any residual solder from the PCB pads, ensuring they are clean and flat. Similar tools as used in step 1 can be utilized. Take care not to damage the pads or solder mask.
6. Solder Paste Printing (Again): Repeat the solder paste printing process described in step 3.
7. Component Mounting: If it’s a new BGA component, check for moisture, and if necessary, dehumidify it before mounting. For reused BGA components, they should undergo reballing before reuse.
8. Mounting BGA Components: Place the PCB with the solder paste onto the worktable. Choose an appropriate suction nozzle and turn on the vacuum pump. Pick up the BGA component with the suction nozzle and align it precisely with the PCB pads. Once aligned, lower the nozzle to mount the BGA component onto the PCB, then turn off the vacuum pump.
9. Reflow Soldering: Set the soldering temperature based on the component size, PCB thickness, etc. The soldering temperature for BGA components is typically about 15 degrees Celsius higher than for traditional SMD components.

The traditional BGA rework process is complex and requires expertise. It’s recommended to use specialized equipment like Silman Tech’s BGA rework station for a more efficient and reliable process.