Hello Amit,

I had the same proplems before, i think the reason there is the solvent
evaporation. the evaporation gas are generated ans gatetherd by the heat. you
can try to leave the wafer on the room temperature ( less than 50) on a whole
day, make it evaporate naturally. It will form a stable uniformity layer. I
think this small trick wii be useful for your work. I always succeed in this
way.

Regards




At 2011-05-18 23:23:10，"amit asthana"  wrote:

>Hello All,
>
>Anyone out there have experience with PerMX 3020 (negative tone resist) dry
>film photoresist from Dupont?
>
>Previously, I have successfully used other PerMX 3000 series resists such as
>3015 and 3050. However I am facing strange problem with 3020 resist. The
>exposed/crosslinked resist  area shown number of blisters and through holes.
>My recipe for the PerMX 3020 is as follows:
>
>Cleaning of Wafer: Acetone, IPA, Nitrogen dry
>Dehydration: 180 deg. C for 20 min.
>Laminator parameter: roller temperature 75 deg C with slowest roller speed
>possible with our laminator.
>Pre Exposure Bake: 95 degree C for 4 min
>Exposure: 300 mj/cm2 and 400 mj/cm2
>Post Exposure Bake: 95 degree C for 4 min (this is when I usually see
>formation of blisters and holes)
>Development: 5 min in PGMEA
>
>Any help in this regards will be deeply appreciated.
>
>Best regards
>
>Amit