Subject: Problem with PMMA exposure/lift off
From: Arash Hazeghi <ahazeghi@stanford.edu>
Date: Fri, 28 Mar 2008 01:24:32 -0700
Fri, 28 Mar 2008 01:24:32 -0700
Hi all,
I have been trying liftoff on my samples recently but it looks like  
either I am doing something wrong or there is an exposure problem  
with eBeam. I am trying to resolve 150nm lines on  300nm 5% 950-K  
PMMA (standard coat procedure). I have tried area exposure dose from  
350uC/cm2 to 430uC/cm2. metal is 80A Pd+200A Pt. lift off was in  
acetone with syringing. looking under the optical microscope some  
higher dose exposures seem to have come out except for there are cuts  
in the thin lines. In other samples looks like the exposed areas were  
also lifted off. I have attached several pictures, exposure does is  
indicated in each filename. Some users have already suggested using  
higher doses which I am trying now, but I'd be happy to hear if there  
are any other comments.

Thank you,
Arash



  

------------------------------------------------------------------------ 
--
Arash Hazeghi

PhD Candidate
Stanford Center for Integrated Systems,
420 Via Palou Mall, CIS-X 300
tel: 650-725-0418
mobile: 650-353-1866
http://www.stanford.edu/~ahazeghi




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Hi all,
I have been trying liftoff on my samples recently but it looks like either I am doing something wrong or there is an exposure problem with eBeam. I am trying to resolve 150nm lines on 300nm 5% 950-K PMMA (standard coat procedure). I have tried area exposure dose from 350uC/cm2 to 430uC/cm2. metal is 80A Pd+200A Pt. lift off was in acetone with syringing. looking under the optical microscope some higher dose exposures seem to have come out except for there are cuts in the thin lines. In other samples looks like the exposed areas were also lifted off. I have attached severalpictures, exposure does is indicated in each filename. Some users have already suggested using higher doses which I am trying now, but I'd be happy to hear if there are any other comments.

Thank you,
Arash





--------------------------------------------------------------------------
Arash Hazeghi

PhD Candidate
Stanford Center for Integrated Systems,
420 Via Palou Mall, CIS-X 300
tel: 650-725-0418
mobile: 650-353-1866
http://www.stanford.edu/~ahazeghi



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