One other thought - the suppliers of the chemistry of desear products did A
LOT of testing to compare the performance of boards produced with each
process - they may be a source of data.

Susan

-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]]On Behalf Of Constantino
J. Gonzalez
Sent: Monday, September 13, 2004 11:59 AM
To: [log in to unmask]
Subject: [IPC-600-6012] Etchback Question


Hello help....

My question is, do you have any knowledge of any studies having been
performed regarding reliability of ethchback vs. non, or low etchback on
innerconnect joints of polyimide PWBs?

My customer is asupplier for an aerospace company, and the issue is that
they recently have found through microsection analysis that some boards they
have already installed in a vehicle are suspect, with regards to etchback.
I am looking for supporting documentation to disposition the boards.  Our
requirement is for etchback per 6012 CL III, but I don't believe they are
necessarily un-usable. The sections are otherwise structurally sound, no
post or plating sep, 1oz and greater conductors, etc.

As always, I appreciate any info you might be able to pass on.

Regards,

Tino Gonzalez