Lee,
    If you use positive resist, expose normally, then use ammonia reversal.
Then flood expose about 2X original exposure you will get a negative angle of 22
degrees.  Let me know if you want to test ammonia reversal.  Bill Moffat

-----Original Message-----
From: Lee, Duhyun [mailto:[email protected]]
Sent: Monday, January 19, 2004 4:14 PM
To: [email protected]
Subject: [mems-talk] negative slope in 6000PY and PMMA


Hi all,

I'm using the negative photoresist of 6000PY(maker : Futurrex) and positive
ER of PMMA(maker : Microchem) for lift-off application.
But I cannot make the cross section to negative slope.
Our spin coater and mask aligner are delta 80T and MA6 from Karl Suss.
and Hot plate is used for baking.
The thickness range I need is about 5um for 6000PY and 100nm for PMMA.
What factor should I consider primarily to get negative slope of them?
How much slope( or angle) can I obtain, if I optimize the condition?

Lee, Duhyun

========================================
[email protected]
Technology Innovation Center(TIC)
Dep. of Advanced Materials Eng.
Sungkyunkwan University, KOREA
Tel +82-31-290-5645
Fax +82-31-290-5644
========================================



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