It will depend on the nature of your metal deposition. If it is E-vap it
is likely there will little reduction of the hole diameter. If it is
some type of more conformal coating method, such as sputtering there
could be a reduction of the diameter equal to the deposited thickness X
2. However, there are phenomenon of self-shadowing so the reduction of
the diameter of the hole on the side facing the deposition source will
be different than the side away from the deposition source.

Also, the reduction may well be hole size dependent. I would make up
samples deposite differing thickness of metal and derive a model for the
hole size reduction versus hole size and metal deposition thickness for
your particular deposition tool.

Ed

-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org] On Behalf Of li shifeng
Sent: Thursday, September 04, 2008 12:18 PM
To: mems-talk@memsnet.org
Subject: [mems-talk] nanohole reducing using the metal thin film
deposition


Hi, I etched 40nm hole arrays on the 15 nm thick silicon membrane. I
plan to deposit 10-20nm metal on the membrane. I am just wondering the
final hole array diameter after the metal deposition.

 Thanks! dlee