1 / 20

McGill Nanotools Microfabrication Processes

McGill Nanotools Microfabrication Processes. Matthieu Nannini Manager URL :: miam2.physics.mcgill.ca. Microfabrication Add material Remove material Pattern material To the outside world Process flow example Idea to device Conclusion. Outline. Atmospheric Chemical Vapour Deposition

erimentha-arianna
Download Presentation

McGill Nanotools Microfabrication Processes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. McGill Nanotools Microfabrication Processes Matthieu Nannini Manager URL :: miam2.physics.mcgill.ca

  2. Microfabrication Add material Remove material Pattern material To the outside world Process flow example Idea to device Conclusion Outline

  3. Atmospheric Chemical Vapour Deposition Reaction between gases ans substrate at high temperature (900-1100°C) Precise control of temperature High purity material Si + O2 SiO2 (dry SiO2) Si + H2O  SiO2 (wet SiO2) Available @ McGill: Oxide thermal growth up to 1.5µm Add material: Thermal processes

  4. Low Pressure Chemical Vapour Deposition Reaction between two gases at high temperature (500-800°C) Precise control of temperature High purity material 3 SiH2Cl2 + 4 NH3 → Si3N4 + 6 HCl + 6 H2 (silicon nitride) SiH4 → Si + 2H2 (polysilicon) Available @ McGill: Silicon Nitride LPCVD Amorphous and polycristalline silicon LPCVD Add material CVD (Chemical Vapor Deposition)

  5. Plasma Enhanced Chemical Vapour Deposition Reaction between two gases @ 300-400°C and enhanced by plasma Allow oxide, nitride or oxynitride to be deposited on metals for insulation or passivation/ High deposition rate: ~1000 A/min Available @ McGill: SiliconOxide Silicon Nitride Silicon Oxynitride (under dev.) Add material: Plasma Enhanced CVD (PECVD)

  6. Evaporation Heat the target material until it melts and evaporates onto the sample Directional coating (shadow effect) Low to high etch rates Stack of material Materials available: Au, Ti, Cr, Pd, Al, Ni, Pt … Add material: PVD (Physical Vapor Deposition) sample

  7. Add material and pattern at once: lift-off Resist coating sample sample UV patterning sample Metal evaporation development sample sample Resist dissolution

  8. Sputtering Bombard the target with plasma discharge that extracts atoms from the target onto the sample Conformal coating Conductive and non conductive material Reactive sputtering with additional gas Stack of material Co-sputtering  alloys Materials available: Au, Ti, Cr, Al, AlN, TiN, TiO2, ITO, Cu, Pd, W, Si, SiC… Add material: PVD (Physical Vapor Deposition) sample

  9. Microfabrication Add material Remove material Pattern material To the outside world Process flow example Idea to device Conclusion Outline

  10. Wet Etch Chemical solution Usually Isotropic (can be anisotropic in crystals) Very selective: resist etch rate vs. material etch rate High etch rate Difficult to control precisely Resolution limitation Batch processing Remove material: Wet Etch Masking material Etching

  11. Dry Etch Gas phase Sputter + chemical etch Anisotropic Less selective High resolution Excellent control Single wafer processing Gas available @ McGill: Oxides/Nitrides: CF4, CHF3, O2, Ar Silicon: HBr, Cl2, Ar Metals: HBr, Cl2, Ar, N2, NF3 Remove material: Dry Etch

  12. DRIE We need 2 gases, one for etching and another one to deposit a protective polymer. We need to alternate etching and deposition then we pulse the gas injection We need energetic ions to remove the polymer on the feature bottom to allow Si etching during SF6 cycle. Remove silicon: Deep Reactive Ion Etching available @ McGill: Tegal SDE 110

  13. Microfabrication Add material Remove material Pattern material To the outside world Process flow example Idea to device Conclusion Outline

  14. Pattern material: Photolithography UV exposition through mask • Resolution (~800nm): • Wavelength (432nm) • mask-substrate distance • resist thickness • To consider • Large exposed area (150mm) • Parallel • Fast • Limited resolution

  15. Pattern material: Mask design • Designing your mask • Knowing what kind of shapes you need • How many mask level ? Alignment needed ?

  16. E-beam expose develop Pattern material: Electrolithography Electron beam direct exposition • Principle: • electron sensitive polymer • Direct beam writing • Resolution: 30nm • E-beam quality (focus, stigmatism, alignment…) • Stability of stage • Thickness of polymer • To consider • Limited writing areas • Serial writing • slow

  17. Microfabrication Add material Remove material Pattern material To the outside world Process flow example Idea to device Conclusion Outline

  18. Dicing: Precision diamond saw to cut out wafer in small dies Blade thicknesses from 100 to 250µm Accurate alignment (~ 50µm) To the outside world: Dicing

  19. WireBonder Connect microelectrodes to the outside world To the outside world: wire bonding

  20. Process flow example SiN backside etch cleaning SiN deposition Top side protection Backside bulk etch Resist patterning Remove protection SiN Dry etch Backside resist patterning with alignment Beware of Powerpoint engineering !!

More Related