Contents
Foreword xiii
Preface xv
Preface to First Edition xix
CHAPTER 1
MEMS: A Technology from Lilliput 1
The Promise of Technology 1
What Are MEMS—or MST? 2
What Is Micromachining? 3
Applications and Markets 4
To MEMS or Not To MEMS? 7
Standards 8
The Psychological Barrier 8
Journals, Conferences, and Web Sites 9
List of Journals and Magazines 9
List of Conferences and Meetings 10
Summary 11
References 11
Selected Bibliography 12
CHAPTER 2
Materials for MEMS 13
Silicon-Compatible Material System 13
Silicon 13
Silicon Oxide and Nitride 19
Thin Metal Films 20
Polymers 21
Other Materials and Substrates 21
Glass and Fused Quartz Substrates 21
Silicon Carbide and Diamond 22
Gallium Arsenide and Other Group III-V Compound Semiconductors 22
Polymers 23
Shape-Memory Alloys 23
Important Material Properties and Physical Effects 24
vii
Piezoresistivity 24
Piezoelectricity 26
Thermoelectricity 29
Summary 31
References 31
Selected Bibliography 32
CHAPTER 3
Processes for Micromachining 33
Basic Process Tools 34
Epitaxy 34
Oxidation 35
Sputter Deposition 35
Evaporation 36
Chemical-Vapor Deposition 37
Spin-On Methods 40
Lithography 40
Etching 44
Advanced Process Tools 55
Anodic Bonding 55
Silicon Direct Bonding 56
Grinding, Polishing, and Chemical-Mechanical Polishing 57
Sol-Gel Deposition Methods 58
Electroplating and Molding 58
Supercritical Drying 60
Self-Assembled Monolayers 61
SU-8 Photosensitive Epoxy 61
Photosensitive Glass 62
EFAB 62
Nonlithographic Microfabrication Technologies 63
Ultraprecision Mechanical Machining 64
Laser Machining 64
Electrodischarge Machining 65
Screen Printing 65
Microcontact Printing/Soft Lithography 66
Nanoimprint Lithography 67
Hot Embossing 67
Ultrasonic Machining 68
Combining the Tools—Examples of Commercial Processes 68
Polysilicon Surface Micromachining 69
Combining Silicon Fusion Bonding with Reactive Ion Etching 71
DRIE of SOI Wafers 71
Single Crystal Reactive Etching and Metallization 72
Summary 74
References 75
Selected Bibliography 77
viii Contents
CHAPTER 4
MEM Structures and Systems in Industrial and Automotive Applications 79
General Design Methodology 79
Techniques for Sensing and Actuation 81
Common Sensing Methods 81
Common Actuation Methods 82
Passive Micromachined Mechanical Structures 85
Fluid Nozzles 85
Hinge Mechanisms 88
Sensors and Analysis Systems 89
Pressure Sensors 89
High-Temperature Pressure Sensors 93
Mass Flow Sensors 94
Acceleration Sensors 96
Angular Rate Sensors and Gyroscopes 104
Carbon Monoxide Gas Sensor 114
Actuators and Actuated Microsystems 116
Thermal Inkjet Heads 116
Micromachined Valves 119
Micropumps 126
Summary 128
References 129
Selected Bibliography 131
CHAPTER 5
MEM Structures and Systems in Photonic Applications 133
Imaging and Displays 133
Infrared Radiation Imager 133
Projection Display with the Digital Micromirror DeviceTM 135
Grating Light Valve™ Display 139
Fiber-Optic Communication Devices 141
Tunable Lasers 142
Wavelength Locker 151
Digital M × N Optical Switch 154
Beam-Steering Micromirror for Photonic Switches and Cross Connects 156
Achromatic Variable Optical Attenuation 161
Summary 165
References 165
Selected Bibliography 167
CHAPTER 6
MEMS Applications in Life Sciences 169
Microfluidics for Biological Applications 169
Pumping in Microfluidic Systems 170
Mixing in Microfluidics 171
DNA Analysis 172
Contents ix
The Structure of DNA 172
PCR 174
PCR on a Chip 174
Electrophoresis on a Chip 176
DNA Hybridization Arrays 180
Microelectrode Arrays 182
DNA Addressing with Microelectrodes 183
Cell Cultures over Microelectrodes 185
Summary 185
References 186
Selected Bibliography 187
CHAPTER 7
MEM Structures and Systems in RF Applications 189
Signal Integrity in RF MEMS 189
Passive Electrical Components: Capacitors and Inductors 190
Quality Factor and Parasitics in Passive Components 190
Surface-Micromachined Variable Capacitors 192
Bulk-Micromachined Variable Capacitors 195
Micromachined Inductors 197
Microelectromechanical Resonators 200
Comb-Drive Resonators 201
Beam Resonators 203
Coupled-Resonator Bandpass Filters 206
Film Bulk Acoustic Resonators 208
Microelectromechanical Switches 211
Membrane Shunt Switch 213
Cantilever Series Switch 213
Summary 214
References 214
Selected Bibliography 216
CHAPTER 8
Packaging and Reliability Considerations for MEMS 217
Key Design and Packaging Considerations 218
Wafer or Wafer-Stack Thickness 219
Wafer Dicing Concerns 219
Thermal Management 220
Stress Isolation 221
Protective Coatings and Media Isolation 222
Hermetic Packaging 223
Calibration and Compensation 224
Die-Attach Processes 225
Wiring and Interconnects 227
Electrical Interconnects 227
Microfluidic Interconnects 231
Optical Interconnects 232
x Contents
Types of Packaging Solutions 233
Ceramic Packaging 233
Metal Packaging 237
Molded Plastic Packaging 240
Quality Control, Reliability, and Failure Analysis 243
Quality Control and Reliability Standards 244
Statistical Methods in Reliability 246
Accelerated Life Modeling 248
Major Failure Modes 249
A Reliability Case Study: The DMD 254
Summary 256
References 257
Selected Bibliography 259
Glossary 261
About the Authors 271
Index 273
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