The Resistive Properties of Thin Carbon Films from Pyrolized SU-8

1. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

2. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 • Project Description…. • Design a die that will use a four point Kelvin bridge resistance measurement for pyrolized SU-8 • Design and manufacture high temperature die housing that will incorporate the resistance measurement • Fabricate die in the INRF • Use the Die Housing to perform the resistance measurements Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

3. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 • What is SU-8? • Photosensitive Epoxy • Originally developed for the electronics industry • Used as a Negative Photoresist • Has many attributes that make it suitable for MEMS Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

4. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 • Pyrolized SU-8… • Different properties manifest for different pyrolysis temperatures • As pyrolysis temperature increases, ρ decreases, vertical shrinkage increases • May achieve very high aspect ratios • Exhibits properties similar to glassy and amorphous carbon Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

5. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 Patterning the Die… SU-8 Pattern Before Pyrolysis Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

6. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 Patterning the Die… Aluminum Pads Metallization Mask Final Die Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

7. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 Carbonization of the SU-8 • Quarter wafers only • 30 minutes at 300 °C • Increased 10 °C/min until 900 °C is achieved • Held for one hour • Cooled for minimum of 8 hours in nitrogen environment Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

8. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 • My Job… • Design Kelvin-Bridge • Acquire Materials • Draw Design • Determine Tolerances • Construct Final Product • Use Kelvin-Bridge • Acquire Data • Determine Accuracy Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

9. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 How does a Kelvin Bridge work? Ohm’s Law: V = IR Therefore… R = V/I Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

10. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 Finding the Resistivity (ρ)… ρ = Resistivity R = Resistance across strip l = length of strip A = Cross-Sectional Area Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

11. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 • Design Requirements… • The Kelvin Bridge must make measurements in temperatures between room and 260 °C • It should achieve an accuracy within 0.1% of expected values • It needs to demonstrate a high level of repeatability and reliability • Safety  Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

12. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 • Design Process… • Incorporate requirements into an initial design • Evaluate design and look at options • Select materials based on the requirements (Teflon, Bakelite, Aluminum) • Draw out plans in AutoCAD • Determine tolerances Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

13. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 Housing Components… Aluminum Heating Mass Teflon Block Aluminum Block Copper Contacts Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

14. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 Complete Design… Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

15. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 Temperature Measurements… • Type K Thermocouple • Two heated dissimilar metals joined at the ends create a continuous current • Alumel and Chromel • Omega Thermometer Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

16. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 Temperature Measurements… Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

17. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 The Outcome… Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

18. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 The Outcome… Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

19. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 The Outcome… Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

20. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 The Outcome… Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

21. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 Final Precautions… Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

22. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 • Setbacks… • Available wire only withstands 200 °C • Pyrolysis tube was inoperable for a week • Empty forming gas tank • Time constraints Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

23. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 Results… Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita

24. The Resistive Properties of Thin Carbon Films from Pyrolized SU-8 • Thanks… • National Science Foundation • Professor Richard Nelson and Professor John LaRue • Allen Kine • Hideo Morita and Farzaneh Bakhshi • Ted Ediss Justin Little Department of Mechanical and Aerospace Engineering University of California, Irvine Funded by the National Science Foundation Mentors: Professor Richard Nelson Professor John Larue Support: Allen Kine and Hideo Morita