Have you tried without HMDS layer? Also, have you checked how much residue is left on the bottom? Yingtao ________________________________________ From: mems-talk-bounces+y.tian2=lboro.ac.uk@memsnet.org [mems-talk- bounces+y.tian2=lboro.ac.uk@memsnet.org] On Behalf Of Yingnan Wang [seirc@msn.com] Sent: 13 February 2012 12:34 To: mems-talk@memsnet.org Subject: [mems-talk] AZ5214E as positive resist Dear all, I am having some trouble in photolithograpy with AZ5214E, which works as positive resist. The pattern I want to make is an array of micron dots, with diameter of 3 microns. But no matter how I change the exposure time, I just cannot develop successfully. I want to know why. The parameters I use are listed below: Photoresist - AZ5214E Substrate - 4" Silicon wafer Step 1. Clean wafer with Acetone, IPA abd DI water and dehydration bake at 150 degrees for 10 minutes. Step 2: Spin coat HMDS at 4000 rpm for 35 seconds, without bake. Step 3: Spin coat AZ5214E at 4000rpm for 45 seconds and hotplate (110 degrees) bake for 90 seconds. Step 4: Expose at 8mW/cm^2 for various exposure time, from 10 to 70 seconds.. Step 5: Develop using MIF 300K developer. Thanks a lot! All the best, WANG, Yingnan