I need to prebake PMMA on the sample which is degraded under high temperatures. It seems that even 1500C could kill the sample. I don't have any experience of use of PMMA prebaked under lower temps (maybe 110-120 degrees is better). As rule of thumb I know that the prebake temperature should be close to boiling temperature of the solvent and higher than Tg of PMMA (1050C). In case of anisole its Tb is about 154 degrees, so I must go lower anyway. Does anyone have any experience in such cases? I need to successfully perform EBL process with CDs about 100 nm (not really small features).
Thanks a lot!
Thanks for the answers!
It also could be that sample is degraded mostly at the dehydration process at the air (w/oxygen). I will try firstly to avoid this step (PMMA has very good adhesion in all the cases) or to do that in oxygen-free atmosphere. PMMA prebake is not so dangerous, because the sample is coated than.
Hi there!
Have you solved this problem? I'm facing the same issue now.
Thank you!
ZD
Hi Zhidong Du!
Actually I'm using 150 degreesC and because the coverage is good, the atmosphere doesn't influence the sample surface. So the problem is still not an issue for me now.
If you need to go much below that T, it maybe useful to increase the time of prebake and to use chlorobenzene solution. But anyway you will not have the same density of the film as for higher temperatures because of the lack of movement of the polymer chains.
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