Thin SU-8 Film Lithography - Curing Images

SU-8 is an epoxy based photoresist.

 

Experimental Procedure

Wafer Preparation

Clean Wafer Dehydration Bake Wafer

Spin Coat

Cover the Solitec spinner's drain and plastic top with a cleanroom wipe. Mount the wafer on the Solitec spinner. Apply a quarter sized puddle of SU-8 to wafer. Ramp to 500 rpm at 100rpm/s (5 seconds) Ramp to 6500 rpm at 300rpm/s (20 seconds). Hold at 6500 rpm for 40 seconds

Softbake

Heat the Cole-Parmer hotplate to 65°C Place the wafer on the hotplate Set the timer to 2 minutes When the time is up change the temperature to 95°C Set the timer to 5 minutes When the time is up transfer the wafer to a wafer holder

Exposure

On the Karl Suss aligner expose the wafer for 12 seconds.

Post Exposure Bake

Heat the Cole-Parmer hotplate to 65°C Place the wafer on the hotplate Set the timer to 1 minute When the time is up change the temperature to 95°C Set the timer to 2 minutes When the time is up transfer the wafer to a wafer holder

Development

Place some SU-8 developer in a glass plate Place the wafer in the developer for 2 minutes The development is very sensitive to the concentration of the developer. After developing a few wafers the development time might need to be increased or new developer should be used.

Curing

Heat the clean oven to 65°C Place the wafer in a metal wafer carrier Place the metal carrier in the oven Set the clean oven to 200°C. This will cause the temperature to ramp up as fast as possible. Set a clean room timer to 30 minutes When the time is up remove the metal carrier from the oven

 

Results

 

Channel Width (um) x Separation (um) Cured Not Cured
2x2
2x8
4x4
4x32