Senior Design II Film Thickness Measurement

1. Senior Design II Film Thickness Measurement P06402 Julian Peters Joe Fitzmyer Brad Demers Coordinator: Dr. Wayne Walter Advisor: Dr. Dale Ewbank Sponsor: Dr. Satish Kandlikar

2. Agenda • Project Overview & Background • Interferometry Background • Analysis • System Operation • System Design • Specifications • Design Challenges • Test Plans • Completion Plans

3. Project Overview – Sponsor’s Major Needs • Ability to determine existence and thickness of film • Cost-effectiveness • Ability to operate in a “dirty” environment • Accuracy, but not as demanding as semiconductor applications • Must be able to take measurement quickly • Must not require constant input from user

4. Project Overview - Background • Meniscus Experiment in RIT Thermal Analysis Lab Figure 1: Moving Meniscus Experiment Figure 2: Heater surface and water nozzle detail

5. Advancing contact line Receding contact line Heated, rotating copper cylinder Direction of Rotation Meniscus Project Overview - Background • Meniscus Experiment in RIT Thermal Analysis Lab • Meniscus Experiment in RIT Thermal Analysis Lab – Unanswered Questions: • Is there a film of adsorbed water left behind the moving meniscus? • How far does it extend? • What is its thickness? Figure 3: Operation of experiment

6. 4) The recombined beam is collected at a sensor. The intensity is measured, and can be compared to the intensity of the original beam. qi 1) Light is emitted from the laser diode. 3)The two reflected beams recombine. The difference in the path length taken by the two beams manifests itself as a phase difference, which can cause attenuation of the beam intensity. Film Surface Substrate Surface 2) Two reflections take place: part of the beam reflects from the film surface, part of it continues through the film and reflects from the substrate surface. Interferometry in a Nutshell Figure 5: Interferometry Basics

7. for s-polarization for p-polarization for s-polarization for p-polarization Interferometry Analysis

8. Analysis of Design • MATLAB code written to simulate reflectance response • Data from numerical experiments • Determine appropriate wavelengths • Analyze experimental data • Most easily identified noise independent parameter of data is the frequency of oscillations

9. Sample MATLAB Results Figure 10: Oscillatory Reflectance Response

10. Sample MATLAB Results Figure 11: Non-Oscillatory Reflectance Response at Zero Film Thickness

11. MATLAB Code Verification Figure 12: Comparison of WVASE32 and MATLAB Results

12. Control Hardware Goniometer Actuators Information Control Laser Diode Power Operator PC Light reflected from surface LabView Data Collection Hardware Photosensor Figure 6: Information and control flow through system Basic System Diagram

13. Off-the-Shelf Components • Laser diode: CPS196 • Goniometers: GNL10-Z6 • Motor Controller: ODC001 • TI OPA129U • NI USB DAQ 6008 • Photodiode: SM05PD1A

14. Purchased Components

15. System DesignPhysical System Assembly Goniometer Photodiode Servo Controller Servo Controller Substrate and Film Breadboard Base Laser Diode

16. System DesignPhysical System Assembly Goniometer Servo Controller Servo Controller Substrate and Film Breadboard Base Base

17. Specifications & Targets • Positioning Accuracy – ± 0.25° • Positioning Precision – ± 0.25° • Film Thickness Accuracy – ± 5 μm • Film Thickness Precision – ± 5 μm • Measurement Time – 30 minutes

18. Design Challenges • Light Source • Beam divergence • Suitability of wavelength to film thickness • Consistency of intensity • Polarization intensity • Focal length • Photodiode • Must accommodate beam divergence • Accuracy

19. Design Challenges • Positioning Equipment • Accuracy • Repeatability • Synchronicity • Alignment • Equipment Mounts • Accuracy • Compensating

20. Design Challenges • PC Interface Hardware / Software • Position control and reporting • Single user input • Collect data from photodiode • Data Interpretation Programming • Fit data to simulation • Measure of confidence

21. Design Challenges • Specific Application to Mensicus Experiment • Optical properties of surface • Beam alignment • Flatness of surface

22. Alignment and Calibration • Goniometer zeroes • Calibration curve • Verify alignment

23. Alignment and Calibration “Zero” is found by reflecting laser back onto itself. 51” Linear-to-angular step size is found by making marks on target at regular linear steps. q

24. Alignment and Calibration

25. Alignment and Calibration

26. Test and Completion Plan • Verify assembly alignment • Labview code • Test against known films • Implement Matlab code • User manual

27. Any Questions?

28. CPS196 Datasheet

45. Control VI

46. Part Prints

47. Sensor-Side Mount

48. Laser Mount

49. Sensor Mount

50. Sample Platform