Subject: | |
From: | |
Date: | Tue, 11 Jun 96 18:20:09 EST |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
Hi;
We use a mechanical scrub (Aluminum Oxide) in a pumice scrubber prior to
resist application. Variables are minimized by normal process controls
(i.e. concentration of Aluminum Oxide, brush pressure, conveyor speed etc.).
What might help before Ni/Au plating, is to chemically clean and
electrolytically copper strike (pattern plate) approx .0001" prior to Ni/Au
plating. This will provide an optimal surface for the Nickel. You might
also want to look at your cleaner and microetch in the Ni/Au preclean
process. Finally, you should contact your photoresist vendor and see if the
resist you are using is optimal for the process you are trying to perform.
Good Luck!
Greg Schroeder
[log in to unmask]
______________________________ Reply Separator _________________________________
Subject: FAB: Manual Scrubbing prior to NiAu
Author: [log in to unmask] at SMTPLINK-HADCO
Date: 6/6/96 10:27 PM
Address,
EXPLANATION:
I have been conducting some experiments on the use of mechanical
and chemical scrubbing on panels prior to resist lamination. We
currently perform a mechanical scrub to all panels prior to resist
lamination.
Based on minimal testing, we are successful in chemical cleaning
panels prior to resist lamination with no resist breakdown in
deep electrolytic Ni and Au. However, in the test process
we conducted a tape test and discovered NiAu peel from the base
copper (no electrolytic copper applied due to reason of test).
The NiAu peel from the copper occurs on mechanical scrubbed
and chemical clean sample panels, but on different sides. The
mechanical scrubbed panel has peel on the component side and the
chemical clean panel has peel on the solder side.
So the problem now points to the method in which we prepare
panels prior to Ni and Au plating. To insure good adhesion
between Ni-copper and Au-Ni, panels are manually scrubbed with an
abrasive pad. Recent observation shows there is a large
variable associated with this type of method.
QUESTION:
-I would like to discuss with other manufacturers who use deep
Ni and Au plating?
-What types of methods are others using to prep panels prior
to Ni and Au plating?
-Is the method chemical or mechanical and if mechanical how are
variables minimized?
Please advise. Thank you.
|
|
|