Anshu,

You can get a rough estimate by putting an optical power meter under your
aligners lamp and measuring it's output.  Then you know how long to expose.
Without a power meter,  make an aluminum foil mask with an eight inch wide
slit aabout an inch long  Put some photoresist on a junk wafer and put the
foil over a real mask in the aligner.  Expose for one second, move the foil
down an eighth of an inch, expose for five seconds, etc.  Then see what
develops.

Marty

Martin O. Patton
Senior Research Engineer
Essential Research Incorporated
6410 Eastland Road
Cleveland, Ohio 44142
www.er.com
(440) 816-9850