We are seeing unusual soldered joints when soldering to components with 
Platinum/Silver metallised terminations. At the margin between the bottom of 
the component termination and the PCB surface there are a number of 
blowholes in the bulk solder. There also appears to be poor wetting to the 
vertical end of the termination itself. All other solder joints on the 
assembly in question are good, well wetted and on a number of other plating 
finishes.

The solder paste is SAC305 and the PCB finish is ENIG. Reflow is carried out 
in a vapour phase process with a maximum assembly temperature of 235 deg. C. 
Time above liquidus (217 Deg C.) is around 50 seconds.

I have requested feedback from the component manufacturer but it's like 
pulling teeth so in the meantime I an seeking your considered opinions.

Many thanks




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Peter Barton
Senior Process Engineer
ACW Technology Ltd
Dinas Isaf West
Tonypandy
Mid Glamorgan. CF40 1XX  Wales

Tel: 01443 425275 (direct)
Fax:  023 8048 4882
International Tel : +44 1443 425200
International Fax : +44 23 8048 4882
Website/URL:  www.acw.co.uk

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