Homemade mask making

film from laserlab had smaller space than line (about 45 micron line to 25 micron space). Wanted equal. 16 exposure gives close to equal, though some lines are wider than others (laserlab problem or design?)

At normal exposure, film from PreTech gives medium sized light features on a dark field which are about 15 microns smaller than design. 10 micron design lines still show up, but are a bit dark, and may not print continuous. They are about 4 microns wide.

Minimum dark feature is about 18 microns. Minimum light feature is about 7 microns.


Note 1: 1/98 a light field mask quite overexposed using 8s+2s. Tried 6s+min (at black edge) good with success, though still perhaps a bit overexposed. In this case, a feature designed as 20 micron dot came out 30 microns on the film, and 23 microns on the final mask. I don't know if this overexposure is because the PR on this batch of wafers is different or if there is some other change. Light is still measuring 15mW/cm^2 on CI2. Same 4/29/98--bad w/ 8s+2s, ok but maybe thin w/5.5s+1.5s.
1/5/00 26mW. neg photomask. 5s+2s very overexposed
Try 4s+1.5s. still overexposed.
1/6/00 Niyaz mask optimized at 3.5s + 1.0sblanket.
2/8/00 4s+1.5s(min on x10) is ok for IMPS mask
5/4/04 on new batch, good results with 6s + 1.75s (Igor Paprotny). note: 4.5 - 1.5s , very unexposed. 5 - 1.5 ok, but still some bubbles.


Christopher.G.Levey@ dartmouth.edu