Check you resist stripper dosing. Over-dosing here may cause high pH,
     which will cause breakdown of SnPb but remain quite invisible until
     after the etcher.

     This is MHO, does not reflect the opinion of my company.

     ytg


______________________________ Reply Separator _________________________________
Subject: [TN] Tin/Lead peeling off
Author:  "TechNet E-Mail Forum." <[log in to unmask]>, [log in to unmask] at
corp
Date:    3/31/98 12:15 AM


Hallo all;
I need help to solve the problem of Tin/Lead peeling off during ecthing process.
Tin/Lead alloy is used as ecth resist in our pattern plating line utilizing
LeaRonal Plutin LA process. The plating time is 7.5min. and Current Density is
1.8~2.0A/dm2, then the resist layer is about 6~8um thick. Seldom did we find
poor plating after pattern plating. But just after ecthing, you can see copper
exposure in some pads or circuit, sometimes it is even worse to find open
circuits or pin holes. The ratio of this kind of problem(referring boards) is
about 3%. Sometimes when we do Hull Cell, the test panel looks dark in high
current density area, sometimes it looks quite good. But the problem happens all
the same. Also we have checked the PH and Cl content of etch solution, it seems
OK.
Can anybody offer suggestions to eliminate this problem?
Thanks in advance.

Ji Jiancheng

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