TMFRecipes
Return to Toronto Microfluidics Foundry Home
RECIPE DUMP
July 2007 - George Ye
A. TO FABRICATE STRAIGHT WALL ON THICK SU-8 SAMPLE
Problem: The features has a large overhanging edge near the top; the walls were slanted
Cause: the photomask was not pressed firmly against the photofilm which causes UV light to leak around the photomask apertures
Solution: before exposure, cover the photomask with a large piece of 3x2 inches glass. Then, apply two thick stacks (10-15) microscope slides on either sides of the cover glass to be used as weight.
Protocol:
Dehydration bake:
1. Dehydration bake @ 200 degrees for about 15 minutes
Spincoating:
1. 500RPM DWELL: 10s ACCELERATION: 10s
2. 2000RPM DWELL: 30s ACCELERATION: 5s
3. 0RPM DWELL: 0s ACCELERATION: 10s
Pre-exposure bake:
1. 7 minutes @ 65 degrees
2. 20 minutes @ 95 degrees
3. allowed to cool to room temperature
Exposure:
1. cover the photomask as described above
2. UV exposure for 20 seconds
Post-exposure bake:
1. 2 minutes @ 65 degrees
2. 7 minutes @ 95 degrees
3. 2 minutes @ 65 degrees
Develop:
1. Develop in 20ml of developer with mild to strong agitation for 20 minutes
2. Replace with 20ml of fresh developer
3. Develop further for another 20 minutes