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Subject: Re: Growth of particles on copper masks in CD-R manufacturing
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Date: 03/03/02 at 3:42 PM
Posted by: Richard Swisher
In Reply to: Growth of particles on copper masks in CD-R manufacturing posted by Jeroen van 't Erve on 02/06/02 at 5:14 AM:
I haven't seen your particles, but your descriptions sounds
like dendrites or needles growing up out of thick, pure metal
deposits. This is a common problem in thick Tin and Lead
deposits. It is a stress relaxation process.
If your process was good and has turned for the worse, I suggest
you look at the levels of residual gases in your process.
Many years ago we "improved" the vacuum level in a machine
that produced 1.2 micrometer pure lead deposits. The product
then produced fast growing lead whiskers all over the place.
It turned out the residual water vapor (and hence Lead Oxide) in
the old deposition process had prevented the pure crystal growth that
gave the problem after the "improvement."
We put in tiny, controlled oxygen bleed and carried on.
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