MEMS Fabrication.ppt

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fabrication technology

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<p>MEMS FabricationBy Thomas Szychowski</p> <p>MEMS overview Micron Made</p> <p>level mechanical parts</p> <p>from transistor materials and metals Der Waals forces</p> <p> Van</p> <p> Intermolecular</p> <p>bonding Plays an important part in design</p> <p>Fabrication Techniques Mask</p> <p>Lithography Injection molding Microstereolithography Silicon Surface Micromachining Silicon Bulk Micromachining</p> <p>Mask Lithography Use</p> <p>of photo resistDissolves under light Hardens under light</p> <p> Positive</p> <p> Negative</p> <p> Both</p> <p>get covered with desired material, then photo resist is dissolved by a solvent</p> <p> Multiple</p> <p>layers Multiple steps</p> <p>Mask Lithography</p> <p>Injection Molding Starts</p> <p>with mask lithography Metal poured over resist Resist gets dissolved Metal form is left for plastic injection molding</p> <p>Injection Molding</p> <p>Microstereolithography </p> <p>Similar principal to mask lithography, but for 3D pieces Uses an active mask</p> <p>Not a physical mask</p> <p>Utilizes a photo-reactive acrylic resin Each layer image projected through a DMD(digital mirror device) Projected into the resin</p> <p>Uses lenses</p> <p>Resin that is illuminated, Cross-links and hardens Piece is then covered in a hardened layer</p> <p>Microstereolithography Dimensional</p> <p>capabilities Lateral and Vertical resolution: 10m Maximum field size: 10.24mm x 7.68mm Structural height: up to 5mm</p> <p>Microstereolithography</p> <p>Microstereolithography</p> <p>Silicon Surface Micromachining</p> <p>Uses the same process as IC fabrication Needs multiple layers to create structures Cheapest form of Micromachining Similar to lithography </p> <p>Sacrificial material Structural material</p> <p>When sacrificial material is removed, only whole structures are left</p> <p>Silicon Surface Micromachining</p> <p>Silicon Surface Micromachining</p> <p>Silicon Surface Micromachining</p> <p>Silicon Bulk Micromachining</p> <p>Done with Crystalline silicon Constructed using etch stop planes Chemical process Anisotropic Etching </p> <p>Speed dependent Directional etch in different crystallographic directions at different rates Slower directions create and etch stop plane</p> <p>Deep Reactive Ion Etching (DRIE)</p> <p>Uses photo resist and a mask to create structures</p> <p>Sapphire Etching</p> <p>Metal Mask 100m etch depth .28m/min etch rate Chlorine etching</p> <p>Pressure Sensor Etching</p> <p>Used on silicon Metal mask .81m etch depth Utilizes Fluorine</p> <p>High-Speed Etching</p> <p>Silicon material 1m/min etch rate W-Si Mask</p> <p>Whacky Neato Pictures</p> <p>Questions</p> <p>References</p> <p>http://home.earthlink.net/~trimmerw/mems/tour.html http://home.earthlink.net/~trimmerw/mems/BM_bulk.h tml http://www.samcointl.com/apps/mems.html http://www.cmf.rl.ac.uk/latest/msl.html http://www.chemguide.co.uk/atoms/bonding/vdw.html Micromachining for Optical and Optoelectronic Systems. MING C. WU</p>