Hi Scott - Rockwell Collins has investigated immersion gold/nickel, OSP,
immersion tin and immersion silver as alternative solderable finishes. The
details of the testing can be found in the following papers:
" A Comparison of Immersion Gold/Electroless Nickel, HASL, and OSP Surface
Finishes for A Chip Scale Packaging Assembly Application", IPC National
Conference: A Summit on Surface Finishes and PWB Solderability,
Proceedings, September 1999.
"An Investigation of the Effects of Printed Wiring Board Surface Finish and
Conformal Coating for BGA Assembly", IPC APEX Conference, Proceedings,
March 2000.
We have begun successfully using each of the various coatings for a number
of programs. Each alternative finish has both positive's and negative's
depending on your soldering process, type of assembly, and use environment.
Good Luck.
Dave Hillman
Rockwell Collins
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"Lefebvre, Scott" <[log in to unmask]>@IPC.ORG> on 11/03/2000 05:45:24
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Subject: [TN] Board Whit Tin finish
I wanted to know what is the consensus on White Tin finish for replacement
of tin lead HASL. Is it compatible with today's component finishes and the
Lead free finishes of tomorrow.
I was told Nickel Gold is preferred but I've had issues with gold
embattlement, and the cost is also a factor. The gold we have on some of
our assemblies has about 5 micro inches and I still do not get as nice of a
solder joint as tin lead.
Scott Lefebvre
Process Engineer
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