[mems-talk] Depositing metals onto plastics and SU-8

[Yue Mun Pun, Jeffrey]

Jesse,
I may not have been the original poster, but I am also attempting to evaporate metals (Titanium or Gold) on uncrosslinked SU-8 2050.  Titanium evaporates in an e-beam evaporator at a relatively low process pressure of 5e-7 millibars.  However, I am not sure about the sublimation temperature nor the intensity of the glow of the light while Titanium is being evaporated.  
I need to evaporate about 25-30nm Titanium on uncrosslinked SU-8 to use this layer as a UV mask for subsequent i-line patterning as well as a good adhesion layer between SU-8 and gold.  It has been reported that Chromium films of at least 25nm is sufficient to block UV light, but I am not so sure of Titanium.  
Can anyone advise on this matter?

Mr. Jeffrey Mun Pun YUE
Division of Bioengineering
Block E3, #05-18, Nanobioanalytics Lab
9 Engineering Drive 1
National University of Singapore
Singapore 117576
Tel: (65) 65165985, Fax: (65) 68723069
E-mail:  g0500396 at nus.edu.sg

-----Original Message-----
From: mems-talk-bounces at memsnet.org [mailto:mems-talk-bounces at memsnet.org] On Behalf Of Jesse D Fowler
Sent: Tuesday, March 06, 2007 1:04 AM
To: General MEMS discussion
Subject: [mems-talk] Depositing metals onto plastics and SU-8

Hello original poster!

I can't find the original email about this, but if I remember properly, 
the poster wants to deposit onto un-crosslinked (unexposed SU-8). 

Something important to think about is what effect the brightly glowing 
source is going to have on your photosensitive substrate. 

I don't know if the source glows at the proper wavelength to expose SU-8, 
but I do know that it's bright enough that we don't look at it without a 
welding glass. At least, in an evaporator. 

I understand there's a glowing plasma in a sputterer, as well. But, I 
don't know how bright that is.

Is your process going to get messed up if the SU-8 is exposed by the metal 
deposition method? 
What if it's only partially exposed?

If so, you're probably going to have to do a few experiments to find a 
solution.