Surface Micromachining: Layer by layer addition Starting from bare silicon wafer, deposit pattern multiple layers to form a(shippable)MEMS wafer 10 mask steps METAL METAL Silicon Substrate Patterned con Substrate Photoresist Completed MEMS wafer Silicon substrat PoLY重 Poly o P。lyo Etch Diced and released mems device Release isotropic chemical etch to remove oxides Special techniques may be used to remove liquid (e.g, critical point drying) Silicon Substrate Assembly= mechanical manipulation of structures (e.g., raising and latching a vertical mirror plate) Various techniques used, some highly proprietary FromCronos/jdsuMumpsuserguideatwww.Memsrus.com
Surface Micromachining: Layer by layer addition Starting from bare silicon wafer, deposit & pattern multiple layers to form a (shippable) MEMS wafer From Cronos/JDSU MUMPS user guide at www.MEMSRUS.com Assembly = mechanical manipulation of structures (e.g., raising and latching a vertical mirror plate) Various techniques used, some highly proprietary Release = isotropic chemical etch to remove oxides Special techniques may be used to remove liquid (e.g., critical point drying) Diced and released MEMS device Completed MEMS wafer ~ 10 mask steps
st TEx Optical mems device PHOTONICS AND MICROMACHINING INSTRUMENTS DIGITAL MICROMIRROR DEVICE DLP PROJECTOR 96365-39 CORPORATE RESEARCH DEVELOPMENT
Texas Instruments Digital Light Projector & DLP PROJECTOR TM 1 st Optical MEMS device
Bulk MEMS Fabrication Pattern selective etch Example:Bulk silicon DRIE: start with unpatterned wafer stack-a wafer-bonded SOl(silicon on insulat (1)Pattern photoresist (2 )DRIE vertical etch photoresist wafer-bonded silicon sacrificial silicon oxide bulk silicon substrate (3)SiO isotropic etch (4)Gold evaporation Narrow features released Wide features just undercut Gold mirrors on top and potentially sides ◎imt rommel
Bulk MEMS Fabrication: Pattern & selective etch (2) DRIE vertical etch samlab bulk silicon substrate Example: Bulk silicon DRIE: start with unpatterned wafer stack – a wafer-bonded SOI (silicon on insulator) wafer-bonded silicon sacrificial silicon oxide (1) Pattern photoresist photoresist (4) Gold evaporation Gold mirrors on top and potentially sides (3) SiO2 isotropic etch Narrow features released, Wide features just undercut