Is your deposition heated or cold? Are you saying the wafer looks black,
or there are black spec.'s? Is the aluminum shiny, dull, or black. It is
somewhat unclear from your email.

Also, when you take a wafer with Aluminum deposited on it with the
"black stuff" have you wet etched it to see if the aluminum is pitted or
rough.

It is very unlikely "spitting" which leaves metal globs, on the
aluminum, but not black materials.

When you refer to "black stuff" is that with observation with the
unaided eye, or under a microscope.

More detail would be helpful. Your problem could be anything.

Ed

-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org] On Behalf Of li shifeng
Sent: Wednesday, April 01, 2009 11:48 AM
To: mems-talk@memsnet.org
Subject: [mems-talk] Pin Holes on the Al Surface


Hi, I used to ebeam to deposit Al on the glass substrate. I found some
black stuffs distributed on the entire Al surface after deposition.
Following dry etching transfer these to the glass substrate and make the
surface very rough. I do not what are these black stuffs and how to get
ride of them. Anyone has the similar experiences and solution.

Thanks!

shifeng