Don't forget excessive "Z" axis expansion.

The above comments are of my own opinion, and
not necessarily that of my employer.

http:\www.hadco.com:8080

Dave Hoover (aka, Groovy)
NPI Mgr HADCO TC2
Watsonville, CA

----------
From: Paul Sevriens <[log in to unmask]>
To: [log in to unmask]
Subject: [TECHNET] Corner cracks in electrolytic copper plating.

=========================================================================
Date: Monday, October 13, 1997 6:13 AM

Dear p.c.b. friends,

Because off problems with some of our production boards I, am making a
listing for the possible causes of corner cracks in electrolytic copper
plating.

>From all the information I got, I made the following schedule:

* Brittle copper
* Excessive brightness
* Excessive levelers
* Resin content contributing to z expansion
* Deletion of nonfuntional pads
* Contaminated copper bath
* Improper current density
* Design

Because of the fact that the cracks only appear on the corners some of
the above described items can possible be excluded.

Who could give me more detailed information?
Are there articles in some magazines about this subject?


With kind regards,


Paul Sevriens.

Process engineer

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