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Mon, 23 Sep 2002 17:13:07 -0500 |
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What types of parts are causing the most problems? For parts that are very fine pitch, tsops, etc we usually do not use a HASL finish. I prefer a immersion gold but hate osp's. HASL finishes have too wide of a process window for these devices. I see much flatter surfaces with alternate finishes. This is especially true with fine pitch on both sides. Most suppliers can control one side fairly well but two sides and it is much harder. The only supplier I have seen do this with a mediocre yield was utilizing a horizontal HASL process. Unfortunately most PCB houses use vertical HASL processing.
Just my $.02
Kathy
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<DIV><FONT size=1>What types of parts are causing the most problems? For
parts that are very fine pitch, tsops, etc we usually do not use a HASL
finish. I prefer a immersion gold but hate osp's. HASL finishes have
too wide of a process window for these devices. I see much flatter
surfaces with alternate finishes. This is especially true with fine pitch
on both sides. Most suppliers can control one side fairly well but two
sides and it is much harder. The only supplier I have seen do this with a
mediocre yield was utilizing a horizontal HASL process. Unfortunately most
PCB houses use vertical HASL processing. </FONT></DIV>
<DIV><FONT size=1></FONT> </DIV>
<DIV><FONT size=1>Just my $.02</FONT></DIV>
<DIV><FONT size=1></FONT> </DIV>
<DIV><FONT size=1>Kathy </FONT></DIV></BODY></HTML>
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Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
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