Pete: A few things to consider.

1. Even though you say the nickel is not passivated how do you know for sure
that it is not? Whether you are running an automated or manual line there
could be delays in transfer time between nickel activation - rinse - copper
plate that could occasionally lead to passivatioin of the surface of the
nickel. See if there are certain cycles or timing issues that could cause
this.

2. What are you using for nickel activation chemistry?  Is the time, temp,
chemical concentration and bath life correct and being properly maintained?
You could be on the edge of the window on one or a combination of these that
causes the problem to intermittently show up.

3. Are your rinse water temps too hot causing premature drying of the part
during transfer?  Are they too cold causing insufficient rinsing of the
previous chemistry resulting in contamination of down stream baths and on
the surface of the part?

4. Is the electrolytic copper rectification working properly? Delays in
applying current or insufficient or excessive current can cause adhesion
problems. In the same vein high or low current density areas can result in
the same type of problem.

5. Check your copper bath for excessive organics.


Michael Barmuta

Staff Engineer

Fluke Corp.

Everett WA

425-446-6076

-----Original Message-----
From: Peter Nemcik [mailto:[log in to unmask]]
Sent: Thursday, February 28, 2002 7:25 AM
To: [log in to unmask]
Subject: Re: [TN] Electroless nickel to electroplated copper separation



Hi Rudy,


it's the other way around: elecrolytic copper on EN, which is plated onto
aluminum.


Regards


Pete




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