Subject: | |
From: | |
Date: | Sun, 28 Jan 1996 10:24:50 -0500 |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
Good day,
We currently are having some considerable difficulty initiating
plating on some copper surface features. This copper surface
has seen a coppper sulfate nickel etching step prior to plating.
Our plating line is composed of electroless plating solutions
(Ni-P, immersion gold and electroless gold). The Nickel plating
on the copper surface is activated via a Pd seeding bath.
We have tried more that a few process changes to enable plating;
increased time in the cleaner, the soft etch, the seeder and some
surface pretreatment. A sulfuric acid dip and an additionnal light
pummice srub have been done. Unfortunetly, none of the above
process (even our rework loop) has yielded acceptable results.
The missing nickel seen here does not seem related to a feature to
feature galvanic effect has we sometimes see. Also, it is not an
oxydation problem, the cleaner removes that effectively.
My questions to the TECHNET community are the following:
-Any of you have seen alteration of copper surfaces in the copper
sulfate etching solution (a MEB analysis shown only a small amount
of nickel on this surface).
-Any comments from platers or board manufacturers who have
experienced the same or similar problems.
-Are there steps in the board manufacturing process known to affect
the copper surface (and cause plating problems).
-Suggestions for cleaning effectively the surface
Thank you.
DENIS DIONNE phone:(514)534-6724 fax:(514)534-7300
IBM Bromont Ltd
Card Plating Engineering
[log in to unmask]
|
|
|