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Date: | Wed, 3 Jun 2009 14:09:47 -0700 |
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A - Commodity build fabricator
B - High-rel fabricator
C - Dicy-cured FR4 170¨¬ C Tg (IPC-4101/24, /26)
D - Phenolic-cured FR4 (IPC-4101/126, /129)
E - Eutectic 230¨¬C thermal excursion
LF - Lead-free 260¨¬C thermal excursion
1 through 6 - number of thermal excursions
P - Pass test without delamination or separation
F - Failed test by demonstration of delamination and/or separation
A + C + E + 1 = P
A + C + E + 2 ¡Â P = ¡Ã F
A + C + E + 3 = F
A + D + E + 1 = P
A + D + E + 2 = P
A + D + E + 3 = P
A + D + E + 4 ¡Â P = ¡Ã F
A + C + LF + 1 ¡Â P = ¡Ã F
A + C + LF + 2 = F
B + C + E + 1 = P
B + C + E + 2 = P
B + C + E + 3 ¡Â P = ¡Ã F
B + C + E + 4 = F
B + D + E + 1 = P
B + D + E + 2 = P
B + D + E + 3 = P
B + D + E + 4 = P
B + D + E + 5 = P
B + D + E + 6 = P
A + D + LF + 1 = P
A + D + LF + 2 = P
A + D + LF + 3 ¡Â P = ¡Ã F
B + D + LF + 1 = P
B + D + LF + 2 = P
B + D + LF + 3 = P
B + D + LF + 4 = P
B + D + LF + 5 = P
B + D + LF + 6 = P
B + C + LF + 1 = P
B + C + LF + 2 ¡Â P + ¡Ã F
B + C + LF + 3 = F
Assuming all other things being equivalent, you can use the above to assess the merit of expectant results. The wisdom of free advice and knowing the source of that same said advice being what it may (or June in this case), you can always buy Werner¡¯s White Paper.
Dewey
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of mp3
Sent: Tuesday, June 02, 2009 10:53 PM
To: [log in to unmask]
Subject: [TN] PTH - 6X thermal stress
Dear all,
Our routine tests for one of our customers include 6X thermal stress on every panel before despatch. Currently we are evaluating a new elctroless chemistry. We would like to have some suggestions from the technetters on which of the electroless chemistries are best suited for meeting the 6X thermal stress tests - Low build / medium build / high build. We do a copper strike after electroless plating and before pattern printing. We also do a plasma desmear followed by a chemical desmear which will achieve an etchback of 5-8 microns. Kindly share any suggestions which you feel will further improve the PTH relaibility. We use 175 Tg laminate and prepreg of Nelco (N4000-6) and achieve a pretty good hole wall during drilling.
In the past we have had a few instances of innerlayer separation during 3x and 6x thermal cycles. Almost all the panels pass 1x thermal stress.
looking forward for the valuable inputs
Rgds
Pradeep Menon
-------------------------------
Micropack Ltd, Bangalore, India
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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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
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