Hi Mr Paul! Thanks for answering my previous questions. Hope you can still accommodate my other queries. This is about the acceptable criteria of PBGA defects after reflow soldering.
1.What is the allowable (min and max. ball misregistration / misalignment afer reflow)? What is the percentage? 2. Is there an allowable solder beads/solder ball defects underneath the PBGA module, if any, what will be the size and how many are acceptable? 3.Is there a minimum percentage of fillet (insufficient solder defect) thru balls and PCB pads? What is the minimum? 4. How about voids inside the PBGA balls after reflow, is there a minimum size or percentage?
Hope you can still have time to answer these questions, looking for you reply!!! This will be a big help!!!! Thank you so much and more power!
Cases 1-3, those criteria may be specified in more recent versions of ANSI/J-STD-001 and/or ANSI/IPC-A-610. Unfortunately, I do not have any new versions of these specs. that may cover these points. As for voids in BGA joints, I have not seen any specific guidelines on voids. I have been party to companies currently using BGAs who would consider a 10-25% area fraction of one or more voids to be "acceptable," i.e., they would not go through the trouble of rework for such a figure.