The Plasma may emit UV light that exposed your PMMA

Shay

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Hi, All

I posted a message about EBL on the glass substrate couple days ago. I
got several valuable replys. In order to get more help, I would like to
talk a bit of detail about my case.

I try to write patterns on the glass substrate. In order to get rid of
surface charge problem, I sputtered 5nm gold on the top of PMMA. I used
30KV ebeam to expose the patterns. Meanwhile, I used multiple dosage to
find the optimal exposure parameters. The dose factors I used are 1,
1.5, 2.0, 2.5, 3.0. After exposure, I have to strip gold layer to
develop PMMA.  I put some large features in the design so that I can
easly identify the position of the patterns. But, after development, I
cannot find any patterns on the glass substrate. I may believe this
maybe due to underexposure because the layer of gold may absorb some
electrons during exposure.

I am looking for any experiences similar like my case or any working
receipe to share.