EE C247B –ME C218 Introduction to MEMS Design Spring 2021

EE C247B/ME C218: Introduction to MEMSLecture 1m: Admin & Overview

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Copyright @ 2021 Regents of the University of California 1

EE C247B/ME C218: Introduction to MEMS Design LecM 1 C. Nguyen 8/20/09 1

EE C247B – ME C218Introduction to MEMS Design

Spring 2021

Prof. Clark T.-C. Nguyen

Dept. of Electrical Engineering & Computer SciencesUniversity of California at Berkeley

Berkeley, CA 94720

Lecture Module 1: Admin & Overview


Instructor: Prof. Clark T.-C. Nguyen

• Education: Ph.D., University of California at Berkeley, 1994

• 1995: joined the faculty of the Dept. of EECS at the University of Michigan

• 2006: (came back) joined the faculty of the Dept. of EECS at UC Berkeley

• Research: exactly the topic of this course, with a heavy emphasis on vibrating RF MEMS

• Teaching: (at the UofM) mainly transistor circuit & physics; (UC Berkeley) 140/240A, 143, 243, 245,247B/ME218

• 2001: founded Discera, the first company to commercialize vibrating RF MEMS technology

•Mid-2002 to 2005: DARPA MEMS program manager ran 10 different MEMS-based programs topics: power generation, chip-scale atomic clock, gas

analyzers, nuclear power sources, navigation-grade gyros, on-chip cooling, micro environmental control


Course Overview

• Goals of the course:Accessible to a broad audience (minimal prerequisites)Design emphasis

Exposure to the techniques useful in analytical design of structures, transducers, and process flows

Perspective on MEMS research and commercialization circa 2021

• Related courses at UC Berkeley:EE 143: Microfabrication TechnologyEE 147/247A: Introduction to MEMSME 119: Introduction to MEMS (mainly fabrication)BioEng 121: Introduction to Micro and Nano

Biotechnology and BioMEMS

• Assumed background for EE C247B/ME C218: graduate standing in engineering or physical/bio sciencesknowledge of microfabrication technology


Course Overview

• The mechanics of the course are summarized in the course handouts, described in lecture todaySyllabus (Course Information Sheet)

Course descriptionCourse mechanicsTextbooksGrading policy

ScheduleLecture by lecture timeline w/ associated reading

sectionsConsult this sheet for readings, which are not in the

lecture tableMidterm Exam: Thursday, March 18Final Exam: Wednesday, May 12, 11:30 a.m.-2:30

p.m. (Group 10)Project due date TBD (but near semester’s end)

1 2

3 4


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What Should You Know?

P

P Well - NMOS SubstrateN Well - PMOS Substrate

PNP+ P+ N+ N+

S G D S G D

G

D

S S

D

GSub Sub


What Should You Know?

• Basic circuit analysis & design using op amps

• Example: Find the transfer function vo(s)/vi(s) of the circuit below.

-

+

Cf

Rf

vivo

R1


Lecture Outline

• Reading: Senturia, Chapter 1

• Lecture Topics:Definitions for MEMSMEMS roadmapBenefits of Miniaturization


Angle set by mechanical meansto control the path of light

MEMS: Micro Electro Mechanical System

• A device constructed using micromachining (MEMS) tech.

• A micro-scale or smaller device/system that operates mainly via a mechanical or electromechanical means

• At least some of the signals flowing through a MEMS device are best described in terms of mechanical variables, e.g., displacement, velocity, acceleration, temperature, flow

MEMS

Input:voltage, current

acceleration, velocitylight, heat …

Output:voltage, current

acceleration, velocitylight, heat, …

Control:voltage, current

acceleration velocity

light, heat, …

[Wu, UCLA]Transducer to Convert Controlto a Mechanical Variable (e.g., displacement,

velocity, stress, heat, …)

5 6

7 8


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Other Common Attributes of MEMS

• Feature sizes measured in microns or less

•Merges computation with sensing and actuation to change the way we perceive and control the physical world

• Planar lithographic technology often used for fabricationcan use fab equipment identical to those needed for IC’showever, some fabrication steps transcend those of

conventional IC processing

MEMSTechnology

Gimballed, SpinningMacro-Gyroscope

MicromechanicalVibrating Ring Gyroscope

Signal Conditioning Circuits

80 mm

1 mm

(for 80X sizeReduction)

[Najafi, Michigan]


Silicon Substrate

Glass Substrate

Bulk Micromachining and Bonding

• Use the wafer itself as the structural material

• Adv: very large aspect ratios, thick structures

• Example: deep etching and wafer bonding

Silicon SubstrateSilicon Substrate

Glass Substrate

Silicon Substrate

Metal InterconnectAnchor

MovableStructure Electrode

MicromechanicalVibrating Ring Gyroscope

1 mm

Microrotor(for a microengine)

[Najafi, Michigan][Pisano, UC Berkeley]

EE C247B/ME C218: Introduction to MEMS Design LecM 1 C. Nguyen 8/20/09 11• Fabrication steps compatible with planar IC processing

Surface Micromachining


• Completely monolithic, low phase noise, high-Q oscillator (effectively, an integrated crystal oscillator)

• To allow the use of >600oC processing temperatures, tungsten (instead of aluminum) is used for metallization

OscilloscopeOutput

Waveform

Single-Chip Ckt/MEMS Integration

[Nguyen, Howe 1993][Nguyen, Howe 1993]

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3D Direct-Assembled Tunable L

[Ming Wu, UCLA]


Technology Trend and Roadmap for MEMS

incre

asin

g a

bilit

y t

o c

om

pu

te

increasing ability to sense and act

Nu

mb

er

of

Tra

nsis

tors

Number of Mechanical Components

100

101

102

103

104

105

106

107

108

109

100 101 102 103 104 105 106 107 108 109

AdaptiveOptics

Integrated FluidicSystems

DistributedStructural

ControlTerabit/cm2

Data Storage

Optical Switches& Aligners

InertialNavigationOn a Chip

Displays

Weapons,Safing, Arming,

and Fusing

Majority ofEarly MEMS

Devices(mostly sensors)

ADXL-50

Digital MicromirrorDevice (DMD)

ADXL-278

Future MEMSIntegration Levels

Enabled Applications

OMM 32x32

ADXL-78

CPU’s

Pentium 4

ADXRS

i-STAT 1Caliper

Phased-ArrayAntenna


Example: Micromechanical Accelerometer

• The MEMS Advantage: >30X size reduction for

accelerometer mechanical element allows integration with IC’s

xo

x

a

Acceleration

Inertial Force

Spring

Proof Mass

Basic Operation Principle

400 m

m

Analog Devices ADXL 78

Displacement

maFx i

Tiny mass means small output need integrated transistor

circuits to compensate


DisplaysPhased-ArrayAntenna

Technology Trend and Roadmap for MEMS

incre

asin

g a

bilit

y t

o c

om

pu

te


Nu

mb

er

of

Tra

nsis

tors


100

101

102

103

104

105

106

107

108

109

100 101 102 103 104 105 106 107 108 109

AdaptiveOptics



ControlTerabit/cm2

Data Storage




and Fusing



ADXL-50


ADXL-278



OMM 32x32

ADXL-78

CPU’s

Pentium 4

i-STAT 1

ADXRSCaliper Microfluidic Chip

Adv.: small size, small sample, fast analysis speed

Caliper

Analog Devices ADXRSIntegrated Gyroscope

Adv.: small size

OMM 8x8 OpticalCross-Connect Switch

Adv.: faster switching, low loss, larger networks

Adv.: low loss, fast switching, high fill factor

TI Digital Micromirror Device

13 14

15 16


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Technology Trend and Roadmap for MEMSin

cre

asin

g a

bilit

y t

o c

om

pu

te


Nu

mb

er

of

Tra

nsis

tors


100

101

102

103

104

105

106

107

108

109

100 101 102 103 104 105 106 107 108 109

AdaptiveOptics



ControlTerabit/cm2

Data Storage




and Fusing



ADXL-50


ADXL-278



OMM 32x32

ADXL-78

CPU’s

Pentium 4

incre

asin

g p

ow

er

co

ns

um

pti

on

ADXRS

i-STAT 1Caliper

DisplaysPhased-ArrayAntenna

Lucrative Ultra-Low Power Territory(e.g, mechanically powered devices)


Benefits of Size Reduction: MEMS

MEMS extends the benefits of size reductionbeyond the electrical domain

Performance enhancements for applicationdomains beyond those satisfied by electronics

in the same general categories

Speed

Power Consumption

Complexity

Economy

Frequency , Thermal Time Const.

Actuation Energy , Heating Power

Integration Density , Functionality

Batch Fab. Pot. (esp. for packaging)

Robustness g-Force Resilience

• Benefits of size reduction clear for IC’s in elect. domain size reduction speed, low power, complexity, economy

•MEMS: enables a similar concept, but …


Vibrating RF MEMS


Basic Concept: Scaling Guitar Strings

Guitar String

Guitar

Vibrating “A”String (110 Hz)

High Q

110 Hz Freq.

Vib

. A

mp

litu

de

Low Q

r

ro

m

kf

2

1

Freq. Equation:

Freq.

Stiffness

Mass

fo=8.5MHzQvac =8,000

Qair ~50

mMechanical Resonator

Performance:Lr=40.8mm

mr ~ 10-13 kgWr=8mm, hr=2mmd=1000Å, VP=5VPress.=70mTorr

[Bannon 1996]

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EE C247B –ME C218 Introduction to MEMS Design Spring 2021