Sandhya,
        The small bubbles are probably from the suck back at the resist nozzle.
If it is set too fast it creates a froth of photo resist inside the nozzle, then
it pumps down that froth.  Set the suck back to be very slow and controlled.
This will probably cure the striations as well.  These are generally caused by
a) The resist flowing around particles or projections on the wafer.
                             b) The resist drying at differing rates, a multi
solvent resist system does this.            c) The resist flowing and drying
around small bubbles.  Hope this helps.  Bill Moffat

-----Original Message-----
From: sandhya sandhya [mailto:[email protected]]
Sent: Tuesday, May 27, 2003 3:33 PM
To: [email protected]
Subject: [mems-talk] question regarding photolithography


Hai all,
I am Sandhya,a research student In Boise State University. I have a question
regarding photolithography, I am getting striations and small bubbles in the
resist after spinning and i am using SPR 220.7 resist. Can someone please kindly
say me what might be causing it and what should i do for eliminating them.
Sincerely
Research student
Sandhya Reddy




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