My guess is that your soft bake temp and time is too much. Try hot plate
100C/60sec.

Wei Cheng

-----Original Message-----
From: Yingnan Wang [mailto:seirc@msn.com]
Sent: Monday, February 13, 2012 4:35 AM
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