1. Vertical Pillars for Biological Force Sensing
Class update – August 3rd
Sarah Coulthard, Nahid Harjee, Nathan Klejwa, Ronald Kwon

2. Thick SU-8 Characterization
Wanted 350um layer SU-8
5 layers of 70um using SU
+/- 9um
Reduced bake time
Better mechanical rigidity
Found exposure of 20 x 6s optimal
T-topping (slight) and non-vertical side walls (~3) observed

3. Dicing
After exposure but before develop, dice backside of wafer using wafersaw
Minimize UV exposure
Cutting ~50% through wafer allowed clean breaks

4. Release Testing Optimal adhesion layer: 50A Cr, 250A Au
SU-8 (5um) adhered to quartz for 35min in 49% HF
No stiction observed

5. First Attempt at Fabrication
Fabrication completed, diced and released individually

6. First Attempt at Fabrication
Fabrication completed, diced and released individually
THEY WORK!!!
5 devices were successfully completed
20 more ready for release

13. Calibration and Movie Measured resistance change with displacement
Movies: Simulation and actual

14. Next Steps Calibration Write abstract
3 axis displacement vs. voltage (using probes)
3 axis force vs. voltage (using class cantilevers)
Write abstract
Add 35um spacer layer and test with worms