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Pressure sensor

Pressure sensor. 2.008-spring-2003. Surface Micromachining. Pattern anchors. Deposit sacrificial layer. Deposit/pattern structural layer. Etch sacrificial layer. 2.008-spring-2003. Surface micromachining. Structure sacrificial etchant.

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Pressure sensor

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  1. Pressure sensor 2.008-spring-2003

  2. Surface Micromachining Pattern anchors Deposit sacrificial layer Deposit/pattern structural layer Etch sacrificial layer 2.008-spring-2003

  3. Surface micromachining Structure sacrificial etchant Polysilicon Silicon dioxide HF 􀂄 SiNx PSG HF 􀂄 Silicon dioxide polysilicon XeF2 􀂄 SiNx polysilicon XeF2 􀂄 Aluminum photoresist oxygen plasma 2.008-spring-2003

  4. Residual stress gradients More tensile on top More compressive on top Just right! 2.008-spring-2003

  5. Clean Room 􀂄 Gowning with bunny suit 􀂄 Class 1, 10, 100 A salt grain on a chip 2.008-spring-2003

  6. Class of clean rooms 􀂄 Class 1 means one speckle of 0.5 μ partical in one ft3. 􀂄 Class 10, 100, 1000 􀂄 HEPA filter, AHU 2.008-spring-2003

  7. Air Filters 􀂄 HEPA (High Efficiency Particulate Air) filters 􀂄 High efficiency, low Δp, good loading characteristics 􀂄 Glass fibers in a paper like medium 􀂄 97% retainment of incident particles of 0.3 μm or larger 2.008-spring-2003

  8. Class of clean rooms Class Temp tolerance tolerance 2.008-spring-2003

  9. Particles Class Federal Standard 209; Number of particles per cubic foot 2.008-spring-2003

  10. Toxicity 􀂄 TLV (Threshold Limit Value) 􀂄 Upper limit material concentration that an average healthy person can be exposed without adverse effects, ppm or mg/m3 􀂄 Notorious Poisons 􀂄 CO (100 ppm), CO2 (5000 ppm), HCN (110 ppm), H2S (10 ppm) 􀂄 SO2 (5 ppm), NH3 (50 ppm) 􀂄 Arsenic trioxide AS2O3 (0.1g fatal) 􀂄 Hg (0.1 ppm via skin contact) 􀂄 All material are toxic in sufficient quantity, 5g caffein is fatal. 2.008-spring-2003

  11. MEMS Applications 2.008-spring-2003

  12. Display Technologies Market Leader Screen Size R.& D. Issues ●HDTV for 60” ~ 80” Home Theater 􀁺 ●Digital Presentation for 100 ” ~ 300” Projector 􀁺 ●Key Factor : Brightness 2.008-spring-2003

  13. Brightness of Projection Displays lux = lumen / m2

  14. PHOTONICS AND MICROMACHINING 1st Optical MEMS device DIGITAL MICROMIRROR DEVICE & DLP TM PROJECTOR CORPORATE RESEARCH & DEVELOPMENT 96365-39

  15. DMD Optical Switching Principle DMD Mirror on/off ± 10o Texas Instruments’s Technical Journal: Vol. 15, No. 3, July-Sept. 1998. 2.008-spring-2003

  16. DMD Cell Structure Texas Instruments’s Technical Journal: Vol. 15, No. 3, July-Sept. 1998. 2.008-spring-2003

  17. TMA 2.008-spring-2003

  18. Light Modulation of TMA Thinfilm Micromirror Array 2.008-spring-2003

  19. Pixel Architecture Post contact to actuator Mirror Via contact to MOS Top Electrode PZT Bottom Electrode Supporting Layer Common Electrode Anchor Drain Pad Gate Line Source Line 2.008-spring-2003

  20. TMA vs DMD TMATM (Daewoo Electronics) Piezoelectric DMDTM (Texas Instrument) Electrostatic Actuation 0o ~ 3o (continuous) -10o, 0o, +10o Tilting Angle Linear Simple On/Off Complex Gray Scale Control •Fatigue •Sticking •High Cost •Uniformity Drawbacks 2.008-spring-2003

  21. Micromirror Arrays XGA 1024 X 768 786,432 pixels VGA 640 X 480 307,200 pixels 2.008-spring-2003

  22. Mirror Flatness (VGA) 2.008-spring-2003

  23. Coupled Natures of Thin Film Processes 􀂄 Forward coupling 􀂄 Step coverage, confromality 􀂄 Backward coupling 􀂄 Temperature dependent microstructural degradation 􀂄 Over/under etch, etch stop control 􀂄 Side attack, Passivation breakage 2.008-spring-2003

  24. Evolution of TMA Pixels 2.008-spring-2003

  25. MIT Bow-actuator Nick Conway, MS 2003 End effector Piezoelectric Amplifiers Released 4-bar linkage design Fixed substrate 2.008-spring-2003

  26. Design of nanopipette (2): In-line array of nanopipettes 􀂄 Massive Parallel Nanopipette Array by In- plane Scanning Probe Systems 􀂄 Integration with Microfluidic channels 􀂄 Integration of nanopipettes in AFM in an 100 x 100 array Single nanopipette 2.008-spring-2003

  27. Photonic crystal modeling Microcavity waveguide finite-difference time-domain 1 mesh 2.008-spring-2003

  28. Photonic band gap microcavity waveguide processing 􀂃 design matrix of various geometries: defect lengths, waveguide width, d/a, number of holes 􀂃 Nanofabrication: 􀂃 SiNx mask1 /w electron-beam 􀂃 Proximity pattern transfer to resist 􀂃 130 nm minimum features 􀂃 Hard mask from Cr lift-off 2 􀂃 Optimized Si RIE 1 J. Ferrera, NanoStructures Laboratory, MIT. 2 J. Foresi, Kimerling group, MIT. 2.008-spring-2003

  29. Design Domains 􀂄 Design is a mapping process 􀂄 From “What” to “How” 􀂄 Small scale systems design What How N. P. Suh, Axiomatic Design, Oxford 2.008-spring-2003

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