Lecture 01 Introduction to MEMS_new

8/14/2019 Lecture 01 Introduction to MEMS_new

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Introduction to MEMS

Prof. Tianhong Cui, Mechanical Engineering

ME 8254

Movie

Movie Movie

Overview

What is micromanufacturing and MEMS?

Why the interest in MEMS?

IC Fabrication Processes

Bulk Micromachining Processes

Surface Micromachining Processes

Combined Processes

References

MEMS - evolved from the MicroelectronicsRevolution

IC Industry Timeline

1999

10 million transistors

1947

single transistor

1958

first IC


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Micro-Electro-Mechanical Systems (MEMS) is the

integration of mechanical elements, sensors, actuators, and

electronics on a common substrate through the utilization ofmicrofabrication technology or microtechnology.

So what exactly is MEMS? MEMS Examples

pressure sensors

accelerometersflow sensors

inkjet printers

deformable mirror devices

gas sensors

micromotors

microgears

lab-on-a-chip systems

MEMS Timeline1980

2030

1999

(1.3 million micro-mirrors)TI DMD ?

Bulk micromachinedpressure sensor

General MEMS Advantages

Batch fabrication

Reduced cost

Reduced size

Is everything better smaller?

Reduced power

High precision

New capabilities?

Improved performance?

The MicroTechnology/MEMS Tool Set

Cleanroom plus

microfab processes

+

Micromachining Processes

Standard Integrated Circuit (IC) Processes

Identical to those used in IC fabrication

Generally used for surface micromachining

Surface Micromachining

Additive processes

Bulk Micromachining

Subtractive Process

Dividing line can become very blurry


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Standard IC Processes

Source:CWRU

Source: Jaeger


Photolithography Source:Jaeger


Sputtering

Evaporation

Thermal Oxidation

CVD

Spinning

Epitaxy

1) Deposit/Grow Thin Films


Lithography

Etching Techniques (wet, dry, RIE)

2) Pattern Thin Films


Thermal Diffusion

Ion Implantation

3) Introduce Dopants (to form electrically-activeregions for diodes, transistors, etc.)


wet vs dry

isotropic vs anisotropic

subtractive process

Bulk Micromachining


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Bulk Micromachining

Source: MalufSource: Maluf

Source: Madou


high density ICP plasma high aspect ratio Si structures

cost: $500K

Deep Reactive Ion Etching (DRIE)

Source: LucasNova

Source: AMMISource: STS Source: STS


additive process

structural & sacrificial layers

Surface Micromachining

Source: Sandia


uses x-ray lithography (PMMA), electrodeposition and

molding to produce very high aspect ratio (>100) micro-

structures up to 1000 um tall (1986)

LIGA (lithographie, galvanoformung, abformtechnik)

Source: Madou Source: Kovacs

MEMS Examples

Micro-structures using LIGA

Source: UW


uses optical epoxy negative-resist (SU-8) developed by IBM

to produce high aspect ratio micro-structures (1995)

Poor Mans LIGA

Source: Maluf

UofL Micro-reaction wells: 150 um wide,120 um tall, 50 um wall thickness


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Microreactor SU8 High AR Structures

PZT Cantilever BEAM

Thickness

4.5m, width300m, length1000m15m under thevoltage of 10V OTS coating toprevent fromstiction

Micropump

Bimetallic Thermal actuation Three-layer Silicon The middle layer has 2 check valves

Flowrate 190l/min P 80 mm H2O

Integration

Micromachining processes may be

integrated

Both bulk and surface micromachining maybe performed on a single substrate

Micromachined structures may be

integrated with ICs

MEMS Examples

Micromachined Tips for FEDs and AFMs

Source: IBMSource: Micron (?)


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MEMS Examples

Neural Probes

Source: Mich(K. Wise)

MEMS Examples

Neural Interface Chip

Source: Stanford

MEMS Examples

Micro-Grippers

Source: Berkeley

MEMS Examples

Micro-Tweezers

Source: MEMS Precision Instruments

MEMS Examples

Optical MEMS (MOEMS)

Source: IMC (Sweden), Maluf and TI

MEMS Examples

Accelerometers

Sources: Analog Devices, Lucas NovaSensor, and EG&G IC Sensors


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MEMS Examples

Channels, Nozzles, Flow Structures, and Load Cells

Source: EG&G IC Sensors

MEMS References

Micromechanics and Mems : Classic and Seminal Papers to

1990; by W. Trimmer (Editor)

Micromachined Transducers Sourcebook; G. Kovacs

Fundamentals of Microfabrication; Marc J. Madou

Microsensors; by Richard S. Muller, Roger T. Howe, Stephen

D. Senturia, R. Smith (Editors)

An Introduction to MEMS Engineering; by Nadim Maluf

Silicon Micromachining; by Elwenspoek and Jansen

MEMS WWW Bookstore: http://mems.isi.edu/bookstore/

Documents

Lecture 01 Introduction to MEMS_new