I have an issue with SU-8 2000.5. No matter what I do, I cannot get it to adhere properly to silicon wafers (Si). Unfortunately, the adhesion is nowhere near as strong as it is on glass, and this is causing significant problems.
I’ve tried cleaning the wafers using piranha solution once, and another time with NaOH, but it still doesn’t adhere well. Do you have any suggestions on how I can improve the adhesion?
I would really appreciate any help you can offer.
my method involves 10 minutes of acetone, 10 minutes of propanol, 10 minutes of DI water, 10 minutes of Piranha solution, and then DI water again, finishing with air. I tried the Piranha acid ratio with 3 different proportions: 2:1, 3:1, and 3:2, but still, it didn’t adhere for the SU-8 2000.5 material. I also tested baking temperatures of 180°C and 150°C, but it didn’t work. I tried the same process with NaOH and DI water, but it still didn’t stick. However, it worked relatively well for SU-8 2002 material, but I need a thickness of 500 nanometers. I also tried using the HMDS adsorption method with both condensation and direct injection at 150°C, but it didn’t work either.
