Bulk Micromachining Bulk Micromachining of of

Silicon for MEMSSilicon for MEMS

Mustafa G. Guvench, Ph.D.Mustafa G. Guvench, Ph.D.

University of Southern MaineUniversity of Southern Maine

Single Crystal Silicon for MEMS

Mechanical Material

SILICON?

Stiff => Stiff => Thinning is required for appreciable strainThinning is required for appreciable strain

Single Crystal Silicon for MEMS

Single Crystal Silicon for MEMS

Structure of Single Crystal Silicon

Miller Indices for Single Crystal Silicon

Miller Indices for Single Crystal Silicon

SCS has SCS has anisotropic anisotropic properties:properties:

Electrical, Electrical, Thermal, Thermal, Mechanical, Mechanical, ChemicalChemical

ETCHING for BULK MICROMACHINING(Isotropic/Anisotropic)

ETCHING for BULK MICROMACHINING(Isotropic/Anisotropic)

ETCHING for BULK MICROMACHINING(Cavity/Cantilever Anisotropic)

DRY (Plasma) ETCHING

Deep Reactive Ion Etch (DRIE)

Single Crystal Silicon for MEMS

Single Crystal Silicon for MEMS

Single Crystal Silicon for MEMS

What is MICRO-MACHINING?

What can Micromachined Parts/Systems do for us?

Be a Conduit to Microscopic Domain:

1. Sensing (Information)2. Information Processing 3. Communication4. Manipulation (Actuation and Control)

Why / Why not

SILICON?

Semiconductor: Semiconductor: Active Devices + SensorsActive Devices + Sensors(Photo-Magneto-Strain Sensing)(Photo-Magneto-Strain Sensing)

Insulator:Insulator: SiOSiO22 , Si , Si33NN44 , Glass , Glass

Thin Film Conductor:Thin Film Conductor: Aluminum, Gold, SilicidesAluminum, Gold, Silicides

PhotoLithography:PhotoLithography: Planar control (+ & -)Planar control (+ & -)

Mechanical Material

SILICON?

Stiff => Stiff => Thinning is required for appreciable strainThinning is required for appreciable strain

Micromachining of

SILICON?

MICROMACHINING of SILICON => MICROMACHINING of SILICON => (a) (a) BULK (substrate)BULK (substrate)(b) (b) SURFACE (films)SURFACE (films)

Additive Processes: Additive Processes: Chemical and Physical DepositionChemical and Physical Deposition(Thin Layers only) (Single/Poly)(Thin Layers only) (Single/Poly)

Removal Processes:Removal Processes: Chemical and Physical EtchingChemical and Physical Etching(Wet/Dry/Plasma/Inert/Reactive)(Wet/Dry/Plasma/Inert/Reactive)

(Bulk/Film) (Anisotropic/Isotropic)(Bulk/Film) (Anisotropic/Isotropic)

BULK MICROMACHINING(Etchants: Isotropic/Anisotropic)

BULK MICROMACHINED(Silicon Capillary for Insulin Infuser)

BULK MICROMACHINED(Silicon Capillary for Insulin Infuser)

BULK MICROMACHINED(Silicon Capillary for Insulin Infuser)

BULK MICROMACHINED(Silicon Mask for Cylindrical Micromotion Sensor)

BULK MICROMACHINED(Series Connected Photovoltaic Converter Battery)

BULK MICROMACHINED(Series Connected Photovoltaic Converter Battery)

BULK MICROMACHINED(Series Connected Photovoltaic Converter Battery)

MOTION? HANDLING? ASSEMBLY?COUPLING? =>

MicroElectroMechanicalSytems

M (CMOS-IC Technology) + E (CMOS-IC Technology) +

M (Silicon and Sacrificial Layers) +

O (Aluminum) +

S (IC Packaging Technology)

Three-Layer Poly-Silicon Surface Micromachining Process

(to build Mechanical Parts on CMOS IC)

Final cross sectional view with 7 layersFinal cross sectional view with 7 layers

Three-Layer Poly-Silicon Surface Micromachining Process

Surface Micromachined

Micromachining of Projection Camera

M (CMOS-IC Technology) + E (CMOS-IC Technology) +

M (Silicon and Sacrificial Layers) +

O (Aluminum) +

S (IC Packaging Technology)

M.G.GuvenchM.G.Guvench

Surface Micromachined Silicon SensorsSurface Micromachined Silicon Sensors

M.G.GuvenchM.G.Guvench

Surface Micromachined Silicon SensorsSurface Micromachined Silicon Sensors

M.G.GuvenchM.G.Guvench

Electrostatic Field SensorsElectrostatic Field Sensors

M.G.GuvenchM.G.Guvench

Electrostatic Field SensorsElectrostatic Field Sensors

M.G.GuvenchM.G.Guvench

Electrostatic Field SensorsElectrostatic Field Sensors

M.G.GuvenchM.G.Guvench

Mass (Absorption/Deposition) SensorMass (Absorption/Deposition) Sensor

M.G.GuvenchM.G.Guvench

Mass (Absorption/Deposition) SensorMass (Absorption/Deposition) Sensor

M.G.GuvenchM.G.Guvench

Mass (Absorption/Deposition) SensorMass (Absorption/Deposition) Sensor

M.G.GuvenchM.G.Guvench

Electrostatic Field SensorsElectrostatic Field Sensors

M.G.GuvenchM.G.Guvench

Flow Skin Friction SensorsFlow Skin Friction Sensors

M.G.GuvenchM.G.Guvench

Flow Skin Friction SensorsFlow Skin Friction Sensors

M.G.GuvenchM.G.Guvench

CMOS Analog Chip Design (Operational Amplifier)CMOS Analog Chip Design (Operational Amplifier)

M.G.GuvenchM.G.Guvench

MicroFab Laboratory

Programmable Diffusion/Oxidation System’s Programmable Diffusion/Oxidation System’s Controller in The MicroFab LaboratoryController in The MicroFab Laboratory

Double-Diffused PDouble-Diffused P++NNNN++ Junction PhotoDiode Junction PhotoDiode Made Being Tested in The MicroFabrication Lab.Made Being Tested in The MicroFabrication Lab.

MicroFab Laboratory

Surface Micromachined Silicon SensorsSurface Micromachined Silicon Sensors

M.G.GuvenchM.G.Guvench

3-Poly Surface Micromachining ProcessedSensors

Cross SectionCross Section

MEMS Switch

MEMS MicromotorMEMS Micromotor

A Mass (Absorption/Deposition) SensorA Mass (Absorption/Deposition) Sensor

M.G.GuvenchM.G.Guvench