1. Device Design: Stage 2 (Modified Microchannel Design)
Process Sequence
Begin with four polished Si wafers
Spin SU-8 (negative photoresist) on the Si wafers and pre-bake at 95°C
Align each of the four wafers with one of four masks and expose the SU-8 to ultraviolet light, then post-bake at 95°C
Develop the SU8 so that the unexposed areas are removed
Results in four distinct SU8 molds
Spin PDMS on the SU8 molds less than the vertical dimension of the SU-8 protrusions
Mix PDMS (Sylgard 184, Dow-Corning) 10:1 with curing agent
Spin on PDMS
Dip the Si wafer in a sodium dodecyl sulfate(SDS) adhesion barrier and allow it to dry naturally
Bake in box furnace for 2 hours at 70°C

2. Device Design: Stage 2 (Modified Microchannel Design)
PDMS
Mix PDMS (Sylgard 184, Dow-Corning) 10:1
with curing agent.
Spin on PDMS (purple).
Bake in box furnace for 2 h at 70°C.
STEP 1
STEP 2
STEP 3
SU-8 Photoresist
Spin on SU-8 photoresist (orange)
Pre-bake at 95°C
Align the wafer with one of the four masks
Expose SU-8 to UV light
Post-bake at 95°C
STEP 4
Develop SU-8 in SU-8 developer
Dip wafer in 0.1 M sodium dodecyl sulfate (SDS) adhesion barrier and let dry naturally
STEP 5
Silicon
Start with a 4” diameter Silicon Wafer