1. NanoFab Trainer Update Nick Reeder, April 25, 2014

2. Update to User Interface User can now select the substrate material when starting a new design.

3. Update to Exposure Code Code that creates UV intensity profile now flattens the top of the gaussian profile for wide mask openings and close distances. As the opening narrows or the distance increases, this flattening diminishes. A look-up table determines how quickly the flattening diminishes as distance increases. How to populate this look-up table with realistic numbers?

4. Sample Run with Varying Mask Opening Widths Next slide shows intensity profile for this exposure.

5. Sample Run with Varying Mask Opening Widths

6. Update to Exposure Code Code now handles cases where layer thicknesses are constant for each mask opening, but different for different openings. Sample run:

7. Next Steps for Exposure Code Code still can’t handle cases where Layer thicknesses vary within a mask opening: Difficulty arises from the fact that the rising edge is slant, not vertical. See next slide for proposed strategy.

8. Proposal for Rewriting Exposure Code Current code Compute intensity profile. Specify layer thicknesses. Process grid & structure. -Begin loop for all x. -Begin loop for all t. Compute M. Compute field shoot. Process image t. -End loop for all t. -End loop for all x. Proposed code -Begin loop for all x. Compute intensity at x. Specify layer thicknesses at x. Process grid & structure at x. -Begin loop for all t. Compute M. Compute field shoot. Process image t. -End loop for all t. -End loop for all x.

9. Date Added To-Do Item Who’s Responsible Date Finished 3/16/12Write code to provide top-down view of mask.NR 3/30/12Add Cl 2 as an etchant.NR 2/11/14 3/30/12 Write code to implement polish, given user parameters of grit size & time. NR 3/30/12 Provide algorithm to determine polish rate given material and grit size. JM 4/20/12Incorporate Andrew’s code for photoresist exposure.NR 4/20/12Fix photoresist underhang problem in spin-coat code.NR 5/4/12 Write code to implement stopping powers of layers to determine whether underlying Si is doped during implantation. NR 5/27/12Write code to implement lift-off.NR1/29/14 5/29/12Write code to implement bake of photoresist.NR 5/31/12 Provide realistic limits on the following user-provided parameters: pressure and temperature when performing CVD; dose and ion energy when performing implantation. AS 6/28/12Niu suggests iterating etch code in seconds instead of minutes.NR2/9/14 1/18/13 Provide look-up table data for 1.) CVD deposition rates based on user- supplied pressure & temperature; 2.) evaporation deposition rates based on user-supplied current & voltage; 3.) sputter deposition rates of Au, Ni, Pt, W, Si 3 N 4, Ta 2 O 5, TiO 2, and Si based on user-supplied pressure & power. AS 1/18/13Write code to implement annealing after implantation.NR 1/18/13Write code to implement doping by diffusion.NR

10. Date Added To-Do ItemWho’s Responsible Date Finished 3/1/13 Write code to implement projection lithography as well as contact lithography. NR 4/14/13 Decide whether to accept Nick’s suggested edits (sent on 4/14/13 and 5/8/13) to Andrew’s seventeen tutorial chapters. AS 6/19/13 Surinder suggests automatically filling in dialog-box parameters if user clicks a point in a “View Rate” graph. NR 10/23/13 Jamshid suggests providing link in dialog boxes to display the relevant “View Rate” graph. NR1/21/14 10/30/13 Jamshid’s student Rajput suggests making it easier for user to know which solvents etch which materials. NR1/21/14 11/3/13Fix bug causing photoresist spikes per Jamshid’s student Chico.NR1/6/14 11/3/13Address performance issue per Jamshid’s student Jarrod.NR2/2/14 Write code to track and plot time, cost, quality of user operations.NR Provide algorithm for tracking time, cost, quality of user operations.AS Write code to implement cleaning.NR Write code to implement profilometer.NR Record video clips (in.flv format) of lab operations.AS & JM Write online help text.NR Test the trainer and report problems to Nick.ALL 1/17/14Revise CVD code to distinguish LPCVD and PECVD.NR 1/28/14 Provide empirical algorithm for finding intensity profile at resist surface given intensity, opening width, airgap, resist thickness. AS3/14/14