BGA rework and a primary service that we provide at Circuit Technology Center. Your question has been repeated numerous times. I think the answer is customer specific but not identified in any standards that I'm aware of. It is very common for BGA's with a process related issue to be reflow multiple times. For instance, if you have a solder bridge or short on the assembly at the BGA site you may choose to remove the BGA, reball the BGA and reinstall it to correct the issue. That would suggest a minimum of four reflow cycles since the board also saw reflow during the initial assembly process. As mentioned, this is not an uncommon situation and is down routinely.
Andy Price
Sales Engineer, Circuit Technology Center
Mr. Price has been a key member of the team at Circuit Technology Center since 1985. He has vast expertise, experience and understanding of complex circuit board rework, repair and modification operations. He is one of the most knowledgeable experts in this area across the globe.
Thank you for the question. My belief is in rework you try and replicate the original production process...as much as possible. Therefore, it is best to only solder a component once. If you desolder...then reball + resolder...the component has now been through at least 3 reflows and possible increased component degradation will have occured. However, life is not perfect and sometimes with no new components available, you may have to re-use an old device. As long as tight temperature controls are always used, you should be ok to re-use a component, once. Beyond this, I feel you are asking for trouble and may get field failures later on.
Roger Gibbs
Managing Director, PDR
Twenty years ago Mr. Gibbs, Managing Director of PDR, produced the first rework system based on Focused Infra-Red light energy. PDR now has a 3,500-strong global installation list with top OEMs and EMS providers.
Consider that J-STD-033B limits a component to just one 125 degree C - 96-hour bake cycle. The manufacturer baked it for 48-hours at dry--you would be baking for the remaining 48-hours. If the package exceeds its factory-floor-life again, it can't be baked so it's scrap.
Charles S. Leech Jr.
Director of Engineering, Innovative Drying Co.
Mr. Leech lead a successful 2 year long process development effort that identified the parameters required to rapidly dry moisture sensitive devices while they were encased in the tape and reel format. Mr. Leech has over thirty years of experience as a manufacturing engineering manager in the electronics industry. NOTE: Mr. Leech is no longer working at Innovative Drying Co.
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