I did PR spin coating on trench structure. I used AZ P4620 PR and the thickness or PR is around 11um. The substrate is Si. And my trench structure depth is 141um(negative way). Even though I enhanced the dose of exposure over 8min, there are some remains of PR on the bottom of trench structure. After development, there are some remains of PR still. Can you let me know any tip of PR coating conformally? I guess there are some problems while I did PR spin coating.(500RPM 5sec, 3000RPM 30sec)
Thank you.