Hi Richard - Give me a more detailed explanation of what type of breakdown products your SERA question refers to (I am confused by the term "breakdown product"). SERA testing gives details about metal finishes and how those surfaces get altered by various processing steps. The test method doesn't analyze chemical residues. Dave Hillman Rockwell Collins [log in to unmask] ______________________________ Reply Separator _________________________________ Subject: Re: Re[2]: Mechanism of Wedge Void Formation Author: [log in to unmask] at ccmgw1 Date: 7/17/97 6:26 PM Patty - good reading material - unfortunately haven't read till u mentioned. would like to dispute Lenny's views - have seen too many cross sections to know otherwise. Whenever pinkring occurrs - look at those cross sections carefully - u will notice some sort of copper folding after plating - means had to be minor space - most llikely filled with air - then solution - whether plain shifting or whatever - the wall has either a gough in it - or minute fracture in the oxide layer. Reduced oxide is nice - but is the oxide layer reduced chemically or is it being chemically etched back - be careful when ur chemical supplier says " we have reduced oxide".Can SERA determine breakdown product is left in? When does the reducer have to be changed? And when we speak about multi-layers - 4 - 6 - 8 - 10 - what happens on 16 layer boards - 20 layers? Saw some occurances happen this year on some pretty thick boards - hydrolization of the reducer - ain't a pretty sight when a 20 layer board seperates. Final conclusion as to how and why? Will know in a month or so .... will try to remember to pass info on. Little pressed for time these days .... once i get freed up will try to forward this info through the net. Yes - reduced oxide does help out when using DM - to an extent - but drilling is still where it starts - from there - your guess is as good as mine as to where the acid attack occurrs. best regards Richard Fudalewski Atotech Canada Ltd *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************