We are having a problem soldering Intel 28F004 TSOPs. On some chips, the solder does not wet the leads properly and has a dull appearance. It flakes off rather than scratches when probed with a pick and fractures when temp cycled. The lead material is ALLOY 42 and we know there are issues with that. Some packages solder OK and survive 10 cycles of a -40 to +100 C (2 min. ramp) screen, some don't, even with the same date code. We don't know if what we are seeing is a problem inherent with Alloy 42 or is a solder coating process problem at the manufacturer or combination of both. Does anyone have a similar complaint? Intel says no one else is complaining. Any hints on special fluxes or tests for solderability on the components would be appreciated. We have seen this problem on 28F004 date codes between late 1995 and March of 1996 so far. For those with Alloy 42 questions, a paper published in Soldering and Surface Mount Technology No. 21, October 95 by W. Englemaier and B. Fuentes gives results of an investigation into solder strength of devices using Alloy 42 lead frames. In summary, it was found that at best , strength of the solder joints was about half that of devices utilizing copper lead frames. The authors recommended against use of Alloy 42 in plastic SOICs. Thanks. Randy Johnson Reliability Engineer Woodward Governor Company Loveland, Colorado *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************