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September 2002

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From:
Kathy Kuhlow <[log in to unmask]>
Date:
Mon, 23 Sep 2002 17:13:07 -0500
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"TechNet E-Mail Forum." <[log in to unmask]>, Kathy Kuhlow <[log in to unmask]>
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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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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1"> <META content="MSHTML 6.00.2715.400" name=GENERATOR></HEAD> <BODY style="MARGIN-TOP: 2px; FONT: 8pt MS Sans Serif; MARGIN-LEFT: 2px"> <DIV><FONT size=1>What types of parts are causing the most problems?&nbsp; For parts that are very fine pitch, tsops, etc we usually do not use a HASL finish.&nbsp; I prefer a immersion gold but hate osp's.&nbsp; HASL finishes have too wide of a process window for these devices.&nbsp; I see much flatter surfaces with alternate finishes.&nbsp; This is especially true with fine pitch on both sides.&nbsp; Most suppliers can control one side fairly well but two sides and it is much harder.&nbsp; The only supplier I have seen do this with a mediocre yield was utilizing a horizontal HASL process.&nbsp; Unfortunately most PCB houses use vertical HASL processing.&nbsp; </FONT></DIV> <DIV><FONT size=1></FONT>&nbsp;</DIV> <DIV><FONT size=1>Just my $.02</FONT></DIV> <DIV><FONT size=1></FONT>&nbsp;</DIV> <DIV><FONT size=1>Kathy </FONT></DIV></BODY></HTML> --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest 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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