assembly and testing of a mems mirror for endoscopic oct

Assembly and Testing of a MEAssembly and Testing of a MEMS Mirror for Endoscopic OCMS Mirror for Endoscopic OC

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IMSURE Fellow: Dolly CregerIMSURE Fellow: Dolly Creger

Mentor: William TangMentor: William TangGraduate Student: Jessica AyersGraduate Student: Jessica Ayers

Definitions

Microelectromechanical Systems (MEMS)- micron-scale devices linking mechanical parts to electrical components.

Optical Coherence Tomography (OCT)- Imaging technology which uses infrared light to image cross-sections of biological tissue with micron scale resolution.

Chemical Vapor Deposition (CVD)- A process in which a controlled chemical reaction produces a thin surface film.

Photoresist- A light sensitive coating that is used to transfer the image of a mask onto the surface of a wafer, followed by a reactive ion etch (RIE).

Stiction- The surface tension of liquid on MEMS components.

Shear Mode Quartz- A piezoelectric effect in a lateral plane.

Realm of BiomedicineRealm of Biomedicine

Coronary RestenosisCoronary Restenosis Laryngeal Laryngeal cancer, Barrett’s Esophagus.cancer, Barrett’s Esophagus.

OCT for noninvasive techniques OCT for noninvasive techniques for cancer screening.for cancer screening.

Majority of research lies in lineaMajority of research lies in linear OCT.r OCT.

Trachea, GI Tract, or blood vesTrachea, GI Tract, or blood vessels require a rotary laser beam.sels require a rotary laser beam.

360º rotating devices are curren360º rotating devices are currently limited by the size of the mottly limited by the size of the motor. or. Fig 2. coronary artery restenosis

www.lightlabimaging.com Fig 3. Mouse Trachea www.lightimaging.com

Fig 1. coronary artery comparison www.lightimagin.com

We are working on a different kind of miWe are working on a different kind of micromachine…cromachine…

Simple Micro MachineSimple Micro Machine

Fig 4. SEM Image: Dolly Creger

Our ProjectOur Project

Develop a smaller 360º rotating mirror that Develop a smaller 360º rotating mirror that can fit inside a 1 mm diameter probe.can fit inside a 1 mm diameter probe.

This will cut the size of the current rotating This will cut the size of the current rotating devices in half.devices in half.

Endoscopic ProbeEndoscopic Probe

Fig 5. Conceptual drawing of endoscopic probe. Jessica Ayers UCI

1 mm

Fabrication Fabrication

Commercial PolyMUMPs ProcessCommercial PolyMUMPs Process

Silicon

Silicon NitridePoly 0

1st Oxide

Poly 1

2nd OxidePoly 2

Metal

L-EditL-Edit

592 µm x 527 µm 990 µm x 941 µm

Stiction

Fig 4 and 5. Mirror Assembly Jessica Ayers UCI

Mirror

Assembly

Scratch DriveScratch Drive

Fig 6 and 7. Scratch Drive Array Jessica Ayers UCI

Electrothermal ActuatorsMicrovibromotors, Electrostatic Micro Conveyer, Dipole Surface Drive MicroengineElectrostatic Linear Inchworm Motors Ultrasonic/Magnetic Actuators

520 µm diameter

876 µmdiameter

Stepping motion of the SDA:

Electrostatic load deflects the plate.

Bushing is scratched forward.

Voltage is reduced and the plate is pulled forward.

ResultsResultsScratch Drive: ~200V .5-1.5 HzScratch Drive: ~200V .5-1.5 Hz

StictionStictiona. Evaporationa. Evaporationb. Instantaneous vaporizationb. Instantaneous vaporizationc. Leave submergedc. Leave submerged

AssemblyAssemblya. Probe Stationa. Probe Stationb. Microspatulab. Microspatulac. Magnetismc. Magnetism

Future WorkFuture Work

StictionStictionContinuous laser to vaporize alContinuous laser to vaporize all the liquid instantaneouslyl the liquid instantaneouslyBackside EtchingBackside EtchingShear Mode QuartzShear Mode Quartz

AssemblyAssemblyThicker Ni CoatingThicker Ni CoatingPhotoresist HingesPhotoresist Hinges

Fig 8. Absorption of silicon and water, Jessica Ayers UCI

Special Thanks!Special Thanks!National Science FoundationNational Science Foundation

UROP-IMSUREUROP-IMSURE Said Shokair Said Shokair Jerry McMillan Jerry McMillan

UCIUCI INRFINRF Goran Matejasevic Goran Matejasevic

Professor Willliam TangProfessor Willliam Tang

Jessica AyersJessica Ayers

Charlie WenCharlie Wen

Gloria YangGloria Yang

Le "Yanni" YanLe "Yanni" Yan