Hi, all!

I have an SOI wafer (2µm+0.5µm+380µm) with 50 nm oxide on top and
I have problem patterning them.

I used without problems this litho process: deposition of AZ9260 5 micro, trat
110°C 4 min, exp 20 s, 9.3 mW/cm2, develops 50+10 s for other wafers. I try
also thinner photoresist 1.5 µm with 3.3 s exposure time but without
success. The pattern looks unclear and over expose. I try to reduce the exposure
time (until 10 s) but the result is unchanged.

I found on net that somebody used ink to reduce the reflectivity but I don't
find what type of ink and I'm concerned about the chemical reaction with the
oxide etcher solution after that.

Do any of you know about commercially available ink for this kind of purposes?
Can you suggest me other solutions?


Thanks on advance,


Miss Mihaela Carp
Research Associate, Division of Material Technology
School of Material Science and Engineering
Nanyang Technological University
Phone: +65 6790 4263, Fax: +65 6790 6994