Hi Jonathan! Is it possible that you have converted the solder into tin
oxide? What are the exact conditioning parameters you are subjecting the
solder too (time, temp, pressure, humidity, cycle recipe, etc.)?

Dave Hillman
Rockwell Collins
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Jonathan A Noquil <[log in to unmask]>@IPC.ORG> on
11/08/2000 04:36:54 AM

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Subject:  [TN] Solder Joint Problem


Hello Technetters, esp those deal with SMT, am just wondering
why my solder joint become powdery. I mounted SOIC-8 on a Nickel Au
finished
PCB using 63 Sn /35Pb/2Ag solder paste then subject it to PRCL reliability
test
the solder joint become powdery and i can removed the component
softly. Any explanation for this? I mean why it become powdery. I really
checked the
solder joint after reflow and It was good.

Same thing i did on BGA, i put bumped wafers on steam aged environment
and the solder balls after exposure become powdery.

Any theoretical or actual explanation on this

thanks

Jonathan Noquil
Package/Design (R&D)
Fairchild Semiconductor

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