reliability of oxidized SMT parts soldered with SnPb

PSMN130-200D MOSFET TRANSISTOR D2PAK - failure of some parts led to investigation, oxidization or surface contamination was noticed on remaining parts. The surface contamination could be removed when fingernail was drawn over the bottom terminating surface. To make it more confusing, the parts are 7 years old and were not MBB protected, but were in a controlled atmosphere.Parts are MSL 1. Six parts per board, but only 4 locations indicated random failures. These 4 act as a switch - on/off.The other two are in an active circuit. Question: will the reflow dissolve the surface contaminant? Thermal transfer is not a critical requirement.

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PSMN130-200D MOSFET TRANSISTOR D2PAK - failure of some parts led to investigation, oxidization or surface contamination was noticed on remaining parts. The surface contamination could be removed when fingernail was drawn over the bottom terminating surface. To make it more confusing, the parts are 7 years old and were not MBB protected, but were in a controlled atmosphere.Parts are MSL 1. Six parts per board, but only 4 locations indicated random failures. These 4 act as a switch - on/off.The other two are in an active circuit. Question: will the reflow dissolve the surface contaminant? Thermal transfer is not a critical requirement.

This message was posted the Electronics Forum @

reply »