Enzhu,
      This could be difficult.  A possible but expensive answer may be a 3D
Holographic projection aligner.  Karl Suss used to manufacture one this gives
you the ability to use a variable focus and expose with the same intensity at
different focal lengths from the mask plane.  If you need more information I can
probably locate engineers who have used this sort of system for exposure down
the side of a steeply sloping line with the same C.D. at the top, down the
slope, and at the bottom of the slope.  Bill Moffat

-----Original Message-----
From: Enzhu Liang [mailto:[email protected]]
Sent: Tuesday, November 19, 2002 2:00 AM
To: [email protected]
Subject: [mems-talk] special photolithography needed


Hello everyone,

Can we do intentionally uneven exposure to the photoresist? Just imagine a
semisphere containing the photoresist and I am going to get uniform exposure on
the surface of the semisphere. This will require the UV light intensity stongest
in the center and weakest at the edges.If you happen to know this, could you
please tell me how to do it or suggest some reading about it? Thank you very
much.

Best regards,

　　　　　　　　E.Liang





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