I worked with a deep tank Nickel-Gold line many years ago (nickel sulfamate, 
gold strike, hard gold and soft gold tanks).  Our clean line was basically 
an electroplating clean line, with an acid cleaner, a peroxide-sulfuric 
microetch, sulfuric acid dip, then the nickel bath.  We had a sulfuric dip 
between the nickel and gold strike.  Rinses were tap water, with DI sprays 
over top (came on only when parts were being removed from the rinse).  We 
went into all the electroplating tanks "live", even the nickel bath I 
believe.  The panels to be plated came from either the copper plating line 
or from dry film, so there was definitely no scrubbing done.  If I had to 
live with just one tank for a clean line, it would contain an etching 
cleaner, or at least a micro-etch.

Sometimes I think you can do as much harm as good with scrubbing.  I also am 
vehemently opposed to those dryers out there with chamois covered rollers, 
as I know they can deposit as much as they remove, unless constantly 
replaced.

Hope this helps.

Pat Goldman
[log in to unmask]
 ----------
From: TechNet-request
To: Technet
Subject: FAB: Manual Scrubbing prior to NiAu
Date: Thursday, June 06, 1996 10:00AM

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.