1. SMEAS 2007 Bex, Rob, Georgios, Jason

2. Fabrication Process status...looks like ~45% of the process is completed... Hmmm....

3. Fabrication Progress… We have a total of 5 wafers Used Innotec to deposit 50nm Au and 3nm Ti Deposited HMDS 1.6 μm of Shipley PR were spun Wafers were exposed in KarlSuss2 for 1.6s in contact mode using mask #1 Wafers developed and postbaked

4. Training Completed the following training: - wbgeneral - evalign - MERL Cleanshop on SU-8 and PDMS spinning All training is complete at this point.

5. Procurement Photopatternable Silicone WL-5150 has been ordered. BIGGEST WORRY: Both Shadow mask and laser etch layouts must be modified and resubmitted– so our masks may take another month! Additional transparency or chrome mask may be needed as back-up for previous Mask #2 plans.

6. SNF Shadow Mask Guidelines Guidelines, images, and resources assembled by Beth Pruitt and available at: http://snf.stanford.edu/Process/ Resources/Shadowmasks.html Single metal masks: isotropic etch from one or both sides defines pattern as shown. Resolution not as good as bi-metal but they are less expensive. Get good resolution with thinner masks, but they are more flimsy. Bi-Metal Masks: Edge definition is crisper while mask can be thicker and more robust. "Bridges" in the mask must be at least 50microns and will be more robust if over 100microns. Long bridges -- greater than about 2:1 aspect ratio won't hold up well, short runs of tight spacing are ok if there is enough material around them. We thought we had this point covered! We increased our S- dimensions to avoid this sort of problem… Minimize mask thickness to minimize feature undercutting ( thickness =.001-.002 inches )

7. Shadow Mask Failure Mode Protrusions have a minimum of support with improved geometry

8. Mask Redesign Shadow Mask Durability Wedges of mask material between electrodes not sufficiently supported, possibility for tears.

9. Mask Redesign Shadow Mask Durability Deposit twice using the same mask: 1.Deposit in colored areas 2.Rotate 180º 3.Deposit in dashed areas

10. Movie Time

11. Option 2: Laser Cut Array Laser TypeMin. Spot Size CostLead Time CO250 μm$2001 week Nd:YAG20 μm$3501 week Excimer2 μm$5002-3 weeks Material 25.4 μm gold foil Cost: $200/device Lead Time: 48 hours

12. Example of Nd:Yag Laser Cut

13. Mask Redesign Laser Cut Problem 100um 50um 200um 100um ~50um spot size will give poor quality on 50um feature Double wire width 8x flexural stiffness?

14. Mask Redesign Plan B – Crazy? Make our own shadow mask. DRIE of Si wafer masked with resist patterned using standard chrome litho mask. Lots of issues -gold contaminated -may not be able to deposit

15. Redesign Summary Feedback, please! Plan C – Not Crazy? Shadow Mask -Underetch problem  “open” springs -Durability problem  Rotation of “half-mask” Laser Cut -Double width of wires, or, spend the cash for excimer. -Cost of materials  Move away from gold ($ down, stiffness up) Own Shadow Mask -We must be joking… Plan C -Lift-off, resist mask, PPS, SU8, wirebonded islands, other?