Device Design: Stage 2(Modified Microchannel Design)

Process Sequence 1. Begin with four polished Si wafers2. Spin SU-8 (negative photoresist) on the Si wafers and pre-bake at

95°C3. 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 4. Develop the SU8 so that the unexposed areas are removed

– Results in four distinct SU8 molds 5. 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

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