[mems-talk] Inquiry regarding sidewall deposition of wafersin e-beam metalization

[Bill Moffat]

I agree with Shay.  This is the reason that people use image reversal to
create a reverse slope on the resist side wall to preclude metal build
up on the resist side walls.

Bill Moffat, CEO 
Yield Engineering Systems, Inc. 
203-A Lawrence Drive, Livermore, CA  94551-5152
(925) 373-8353

bmoffat at yieldengineering.com

www.yieldengineering.com


-----Original Message-----
From: mems-talk-bounces at memsnet.org
[mailto:mems-talk-bounces at memsnet.org] On Behalf Of shay kaplan
Sent: Tuesday, June 26, 2007 12:51 PM
To: 'polly'; 'General MEMS discussion'
Subject: RE: [mems-talk] Inquiry regarding sidewall deposition of
wafersin e-beam metalization

In ebeam evaporation, the process is a line of site process. i.e. the
atoms / molecules fly on a straight line from the source to the surface.
For these reason, the thickness is proportional to the cosine of the
angle. A 90 deg wall will not get coated. However, in some systems the
wafers are tilted and are rotating during evaporation (planetary
fixture). In such a system one get can some material on the sidewall
depending on the system geometry

shay