Hi Madhav,

If I understand your question correctly, you want to know whether the PMMA
layer is affected by the evaporation process.  I am not familiar with your
particular evaporator, but I have evaporated a variety of metals on PMMA
resists (patterned with e-beam lithography) for liftoff without any
difficulty.  The only problem I can think of is if the temperature of your
evaporation process goes above the glass transition temperature for PMMA
(around 125 degrees celsius for MicroChem PMMA), which would cause the
resist to reflow.  I don't anticipate this being a problem, but you could
check to make sure.

Regards,

Michael Rust
University of Cincinnati

-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org]On Behalf Of madhav rao
Sent: Monday, October 23, 2006 1:48 PM
To: General MEMS discussion
Subject: [mems-talk] Nickel evaporation on PMMA!!!


Hi All,
       I am going through all possible combinations
and conditions to grow Nickel Dots. I am looking
forward to grow Nickel Dots using electron
beam lithography. Hence I would be using PMMA(poly
methyl methacrylate) e-beam resist. After patterning
this resist, we need to evaporate Nickel through
Edwards 306 Evaporator. I just wanted to know, whether
this PMMA on Silicon wafer during Nickel Evaporation
gets affected. Let me know about this.