NanoFabrication workshop

"Nanofabrication Workshop Instructions The following information was used in the summer of 2015 to conduct a 5 day workshop (3 to 4 hours per day) conducted by Salt Lake Community College at the Utah Nanofab at the University of Utah. The procedures outlined in this document were followed at the Utah Nanofab Nanofab Utah and may not work for your facility as written. Please do not attempt without proper safety, planning and adaptation for your facility. Resources and procedures related to the pressure sensor were developed by the Southwest Center for Microsystems Education (SCME) an National Science Foundation ATE Center, please see their website for the latest editions of the power point lectures and additional kits and materials at: Southwest Center for Microsystems Education We recommend additional information available at Nano 4 me to supplement the lectures included with this set of instructions. We found it helpful to partially process several pressure sensor wafers to various stages in order to replace the inevitable broken wafers. Workshop Schedule Day Activity Resources Day 1 1. Welcome (20 min) 2. Intro Presentation (40 min) 3. Pressure sensor can activity (60 min) 4. Break (10 min) 5. Safety Lecture (80 min) 6. Gowning Training (20 min) 7. Wrap up Day 1 (10 min) Power point Lectures: 01, MicroscaleProcessing covered during step 2 and 02, Building a Model Pressure Sensor (SCME) Safety videos for used for the Utah Nanofab can be found at: https://www.nanofab.utah.edu/index/about-us/lab-members/trainingvideos#safety Day 2 1. Welcome (10 min) 2. Clean Room Tour (20 min) 3. Microheater photolithography (60 min) 4. Etching Mo/Si layer (45 min) 5. Heated Aluminum Under-etch (30 min) 6. Testing on 4 point probe (60 min) 7. Wrap up Day 2 (15 min) Power point Lecture: During the etching steps we reviewed the lecture: 03,Micro Heater Fabrication Day 3 1. Welcome & Clean Room Entry (15 min) 2. Pressure Sensor Backside PL (30 min) 3. Reactive Ion Etching (60 min) 4. Lift off Resist (45 min) 5. Frontside/Backside Alignment (60 min) 6. Develop & Inspection (25 min) 7. Wrap Up Day 3 (5 min) Power Point Lecture: 04,Microfabrication Steps for pressure sensors (SCME) Day 4 1. Welcome & Clean Room Entry (15 min) 2. e-beam Deposition (45 min) 3. Lift off for gold removal (45 min) 4. Etch pressure cavities Step 1 (30 min) 5. Profile Measurements (20 min) 6. 3D Optical Microscope Training (40 min) 7. Class on a chip Demonstration (30 min) 8. Etch Step 2 (10 min) 9. Wrap Up Day 4 (5 min) Class on a Chip is a pre-packaged MEMS demonstration device sold commercially at http://www.classonachip.com/ Day 5 1. Welcome & Clean Room Entry (30 min) 2. Testing of Pressure Sensors (90 min) 3. Electron Microscopy (90 min) 4. Graduation! (30 min) Testing procedures are available from SCME. WARNING: The following procedures are included only as an outline of what needs to be done. Please do not attempt without proper safety, planning and adaptation for your facility. Pressure Sensor Process (Developed at SCME and adapted by the Utah Nanofab) 1. Acquire mask file and masks (1500 photoresist type). a. One mask file for the membrane – Available from SCME b. One mask file for the gold resistors- Available from SCME 2. Run Heidelberg mask generator for both masks a. When setting up both masks make sure you don’t select inverted(want darkfield) b. Process usually takes about 6 hours for each mask. 3. Deposit Silicon Nitrate onto wafers CVD a. Process usually takes about 3 to 4 hours. i. Silicon Nitrate thickness 1. Wafer #1-Front(860, 856, 848, 851, 843) nm 2. Wafer #2- Middle(786, 780, 773, 774,765) nm 3. Wafer #3 – Back(704, 702, 687, 685, 676) nm 4. Backside Photolithography a. Spin 1813 – 30 secs @ 1500 rpm b. Bake – 1 min 30 sec c. Expose for 13 sec d. Develop 45 sec e. SRD 5. Ion etching using Oxford 80 a. Sopcf4o2.rec – 20 mins i. 125 watts, 75 torrs, 34 sccm for cf4, 3.4 for o2 6. Rinse back and frontside with acetone and IPA to remove photoresist 7. Front side Photolithography a. Spin LOR_b - 45 secs @ 2000 rpm (Lift off resist) b. Bake – 5 mins c. Spin on 1813 – 30 secs @ 1500 d. Bake – 1 min e. Backside align f. Expose for 15 secs g. Develop – 5 mins h. SRD 8. Gold Deposition using Egun a. Pump down time – 1 hour b. Gold weight – 1.528 g c. Deposition time – 30 mins (Cr and Au) i. 30 mA for cr ii. 50 mA for Au iii. Gold thickness was 225 nm 9. Gold lift off a. Lift off using sonic bath using acetone – 15 mins b. SRD 10. LOR Lift off a. Lift off using KOH in room temperature bath 11. Si Etch a. KOH Bath at 105 °C – 2 hrs i. Etch rate ≈ 175 um/hr b. KOH Bath at 95 °C – 90 mins i. Etch rate ≈ 120 um/hr c. KOH Bath at 80 °C – 30 mins Figure shows the pressure sensor from the top on the left and through the cavity from the bottom on the right. Microheater Process Steps (Developed at the Utah Nanofab) 1. Use Finest glass slides 35 x 75 x 1 mm (1 for each participant) 2. Deposit heater material a. Denton sputter system, Load Al, Mo, and Si targets b. Put Mo target in one of the RF positions (cathode 1 or 2) and Si in the other RF, and Al in a DC position c. Ar Flow: 60% d. Al: 300 W 15 min e. Si: 200 W 5 min f. SiMo: cosputter 200 W DC (si), 120 W 20 min RF (Mo) 10 min g. Si: 200 W 5 min h. Total thickness: 550 nm, Sheet resistance 50 Ohms/sq 3. Pattern Si/SiMo/Si a. Spin S1813 b. Bake 110 C 10 min c. Expose 12 seconds with heater structures mask d. Develop 1 min AZ 352 or 300 MIF e. DI Rinse, N2 Dry 4. Etch Si/SiMo/Si a. bSi-SiMo recipe Oxford 80 b. 8 min for 550 nm (We have been doing 30 min) c. SF6 26 sccm d. 75 mT e. 96.6W showing (DC Bias drops quickly to 37 and then slowly to 28 over course of the run) 5. Etch Al a. Al-11 Etch about 1/8” deep in a thick glass pyrex dish b. Set hot plate to ?? C c. Underetch for about 25 min (at 80 C for 15 minutes almost completely etched all the Al) d. DI rinse, DO NOT N2 Dry! e. Acetone rinse f. IPA rinse g. This would be a great spot to do supercritical drying if we had it. h. Set on hot plate on Al foil at >120 C for 5 minutes to dry i. Do not N2 blow dry or heaters will fly away 6. Testing a. Keithley probe station b. Slowly ramp from 1 mA up to 40 mA (try .0005 A steps with 1 second delay times) and observe with video camera. c. Set video camera to nightshot mode (switch on inside left of camera.) d. Graph resistance and record video and ooh and ahh as it heats up e. Start Kite Program f. File open -> resistance g. On the left panel make sure that you have res2t chosen under 2 wire resistor h. Test the probes on the same pad to verify there is no resistance, i. Select the correct SMU on the main A & B boxes j. Press force measurement k. Adjust the settings as usual l. Use timing tab to set the timing delay for each step when you are pulsing in current list sweep but it should be 0 for current Sweep. Figure shows a microheater glowing and deforming due to resistive heating in the microprobe station. Nanofabrication Workshop Instructions The following information was used in the summer of 2015 to conduct a 5 day workshop (3 to 4 hours per day) conducted by Salt Lake Community College at the Utah Nanofab at the University of Utah. The procedures outlined in this document were followed at the Utah Nanofab Nanofab Utah and may not work for your facility as written. Please do not attempt without proper safety, planning and adaptation for your facility. Resources and procedures related to the pressure sensor were developed by the Southwest Center for Microsystems Education (SCME) an National Science Foundation ATE Center, please see their website for the latest editions of the power point lectures and additional kits and materials at: Southwest Center for Microsystems Education We recommend additional information available at Nano 4 me to supplement the lectures included with this set of instructions. We found it helpful to partially process several pressure sensor wafers to various stages in order to replace the inevitable broken wafers. Workshop Schedule Day Activity Resources Day 1 1. Welcome (20 min) 2. Intro Presentation (40 min) 3. Pressure sensor can activity (60 min) 4. Break (10 min) 5. Safety Lecture (80 min) 6. Gowning Training (20 min) 7. Wrap up Day 1 (10 min) Power point Lectures: 01, MicroscaleProcessing covered during step 2 and 02, Building a Model Pressure Sensor (SCME) Safety videos for used for the Utah Nanofab can be found at: https://www.nanofab.utah.edu/index/about-us/lab-members/trainingvideos#safety Day 2 1. Welcome (10 min) 2. Clean Room Tour (20 min) 3. Microheater photolithography (60 min) 4. Etching Mo/Si layer (45 min) 5. Heated Aluminum Under-etch (30 min) 6. Testing on 4 point probe (60 min) 7. Wrap up Day 2 (15 min) Power point Lecture: During the etching steps we reviewed the lecture: 03,Micro Heater Fabrication Day 3 1. Welcome & Clean Room Entry (15 min) 2. Pressure Sensor Backside PL (30 min) 3. Reactive Ion Etching (60 min) 4. Lift off Resist (45 min) 5. Frontside/Backside Alignment (60 min) 6. Develop & Inspection (25 min) 7. Wrap Up Day 3 (5 min) Power Point Lecture: 04,Microfabrication Steps for pressure sensors (SCME) Day 4 1. Welcome & Clean Room Entry (15 min) 2. e-beam Deposition (45 min) 3. Lift off for gold removal (45 min) 4. Etch pressure cavities Step 1 (30 min) 5. Profile Measurements (20 min) 6. 3D Optical Microscope Training (40 min) 7. Class on a chip Demonstration (30 min) 8. Etch Step 2 (10 min) 9. Wrap Up Day 4 (5 min) Class on a Chip is a pre-packaged MEMS demonstration device sold commercially at http://www.classonachip.com/ Day 5 1. Welcome & Clean Room Entry (30 min) 2. Testing of Pressure Sensors (90 min) 3. Electron Microscopy (90 min) 4. Graduation! (30 min) Testing procedures are available from SCME. WARNING: The following procedures are included only as an outline of what needs to be done. Please do not attempt without proper safety, planning and adaptation for your facility. Pressure Sensor Process (Developed at SCME and adapted by the Utah Nanofab) 1. Acquire mask file and masks (1500 photoresist type). a. One mask file for the membrane – Available from SCME b. One mask file for the gold resistors- Available from SCME 2. Run Heidelberg mask generator for both masks a. When setting up both masks make sure you don’t select inverted(want darkfield) b. Process usually takes about 6 hours for each mask. 3. Deposit Silicon Nitrate onto wafers CVD a. Process usually takes about 3 to 4 hours. i. Silicon Nitrate thickness 1. Wafer #1-Front(860, 856, 848, 851, 843) nm 2. Wafer #2- Middle(786, 780, 773, 774,765) nm 3. Wafer #3 – Back(704, 702, 687, 685, 676) nm 4. Backside Photolithography a. Spin 1813 – 30 secs @ 1500 rpm b. Bake – 1 min 30 sec c. Expose for 13 sec d. Develop 45 sec e. SRD 5. Ion etching using Oxford 80 a. Sopcf4o2.rec – 20 mins i. 125 watts, 75 torrs, 34 sccm for cf4, 3.4 for o2 6. Rinse back and frontside with acetone and IPA to remove photoresist 7. Front side Photolithography a. Spin LOR_b - 45 secs @ 2000 rpm (Lift off resist) b. Bake – 5 mins c. Spin on 1813 – 30 secs @ 1500 d. Bake – 1 min e. Backside align f. Expose for 15 secs g. Develop – 5 mins h. SRD 8. Gold Deposition using Egun a. Pump down time – 1 hour b. Gold weight – 1.528 g c. Deposition time – 30 mins (Cr and Au) i. 30 mA for cr ii. 50 mA for Au iii. Gold thickness was 225 nm 9. Gold lift off a. Lift off using sonic bath using acetone – 15 mins b. SRD 10. LOR Lift off a. Lift off using KOH in room temperature bath 11. Si Etch a. KOH Bath at 105 °C – 2 hrs i. Etch rate ≈ 175 um/hr b. KOH Bath at 95 °C – 90 mins i. Etch rate ≈ 120 um/hr c. KOH Bath at 80 °C – 30 mins Figure shows the pressure sensor from the top on the left and through the cavity from the bottom on the right. Microheater Process Steps (Developed at the Utah Nanofab) 1. Use Finest glass slides 35 x 75 x 1 mm (1 for each participant) 2. Deposit heater material a. Denton sputter system, Load Al, Mo, and Si targets b. Put Mo target in one of the RF positions (cathode 1 or 2) and Si in the other RF, and Al in a DC position c. Ar Flow: 60% d. Al: 300 W 15 min e. Si: 200 W 5 min f. SiMo: cosputter 200 W DC (si), 120 W 20 min RF (Mo) 10 min g. Si: 200 W 5 min h. Total thickness: 550 nm, Sheet resistance 50 Ohms/sq 3. Pattern Si/SiMo/Si a. Spin S1813 b. Bake 110 C 10 min c. Expose 12 seconds with heater structures mask d. Develop 1 min AZ 352 or 300 MIF e. DI Rinse, N2 Dry 4. Etch Si/SiMo/Si a. bSi-SiMo recipe Oxford 80 b. 8 min for 550 nm (We have been doing 30 min) c. SF6 26 sccm d. 75 mT e. 96.6W showing (DC Bias drops quickly to 37 and then slowly to 28 over course of the run) 5. Etch Al a. Al-11 Etch about 1/8” deep in a thick glass pyrex dish b. Set hot plate to ?? C c. Underetch for about 25 min (at 80 C for 15 minutes almost completely etched all the Al) d. DI rinse, DO NOT N2 Dry! e. Acetone rinse f. IPA rinse g. This would be a great spot to do supercritical drying if we had it. h. Set on hot plate on Al foil at >120 C for 5 minutes to dry i. Do not N2 blow dry or heaters will fly away 6. Testing a. Keithley probe station b. Slowly ramp from 1 mA up to 40 mA (try .0005 A steps with 1 second delay times) and observe with video camera. c. Set video camera to nightshot mode (switch on inside left of camera.) d. Graph resistance and record video and ooh and ahh as it heats up e. Start Kite Program f. File open -> resistance g. On the left panel make sure that you have res2t chosen under 2 wire resistor h. Test the probes on the same pad to verify there is no resistance, i. Select the correct SMU on the main A & B boxes j. Press force measurement k. Adjust the settings as usual l. Use timing tab to set the timing delay for each step when you are pulsing in current list sweep but it should be 0 for current Sweep. Figure shows a microheater glowing and deforming due to resistive heating in the microprobe station. "