微机电系统基础(英文版.第2版)

.1.3.4 actuators considerations 35
summary 36
problems 37
references 41
chapter 2 first-pass introduction to microfabrication 47
2.0 preview 47
2.1 overview of microfabrication 47
2.2 essential overview of frequently used microfabrication processes 51
2.2.1 photolithography 51
2.2.2 thin film deposition 51
2.2.3 thermal oxidation of silicon 55
2.2.4 wet etching 55
2.2.5 silicon anisotropic etching 57
2.2.6 plasma etching and reactive ion etching 57
2.2.7 doping 58
2.2.8 wafer dicing 59
2.2.9 wafer bonding 60
2.3 the microelectronics fabrication process flow 61
2.4 silicon-based mems processes 63
2.5 packaging and integration 69
2.5.1 integration options 69
2.5.2 encapsulation 71
2.6 new materials and fabrication processes 71
2.7 process selection and design 73
2.7.1 points of consideration for deposition processes 73
2.7.2 points of consideration for etching processes 73
2.7.3 ideal rules for building a process flow 75
2.7.4 rules for building a robust process 75
summary 77
problems 77
references 79
chapter 3 review of essential electrical and mechanical concepts 84
3.0 preview 84
3.1 conductivity of semiconductors 85
3.1.1 semiconductor materials 85
3.1.2 calculation of charge carrier concentration 86
3.1.3 conductivity and resistivity 89
3.2 crystal planes and orientations 93
3.3 stress and strain 96
3.3.1 internal force analysis: newton’s laws of motion 96
3.3.2 definitions of stress and strain 98
3.3.3 general scalar relation between tensile stress and strain 101
3.3.4 mechanical properties of silicon and related thin films 103
3.3.5 general stress—strain relations 105
3.4 flexural beam bending analysis under simple loading conditions 107
3.4.1 types of beams 108
3.4.2 longitudinal strain under pure bending 110
3.4.3 deflection of beams 112
3.4.4 finding the spring constants 113
3.5 torsional deflections 118
3.6 intrinsic stress 120
3.7 dynamic system, resonant frequency, and quality factor 125
3.7.1 dynamic system and governing equation 125
3.7.2 response under sinusoidal resonant input 126
3.7.3 damping and quality factor 128
3.7.4 resonant frequency and bandwidth 128
3.8 active tuning of spring constant and resonant frequency 129
3.9 a list of suggested courses and books 130
summary 131
problems 132
references 136
chapter 4 electrostatic sensing and actuation 141
4.0 preview 141
4.1 introduction to electrostatic sensors and actuators 141
4.2 parallel-plate capacitor 143
4.2.1 capacitance of parallel plates 143
4.2.2 equilibrium position of electrostatic actuator under bias 146
4.2.3 pull-in effect of parallel-plate actuators 149
4.3 applications of parallel-plate capacitors 154
4.3.1 inertia sensor 155
4.3.2 pressure sensor 160
4.3.3 flow sensor 165
4.3.4 tactile sensor 168
4.3.5 parallel-plate actuators 170
4.4 interdigitated finger capacitors 171
4.5 applications of comb-drive devices 176
4.5.1 inertia sensors 176
4.5.2 actuators 180
summary 182
problems 182
references 186
chapter 5 thermal sensing and actuation 190
5.0 preview 190
5.1 introduction 190
5.1.1 thermal sensors 190
5.1.2 thermal actuators 191
5.1.3 fundamentals of thermal transfer 191
5.2 sensors and actuators based on thermal expansion 196
5.2.1 thermal bimorph principle 198
5.2.2 thermal actuators with a single material 205
5.3 thermal couples 207
5.4 thermal resistors 210
5.5 applications 212
5.5.1 inertia sensors 213
5.5.2 flow sensors 215
5.5.3 infrared sensors 228
5.5.4 other sensors 231
summary 236
problems 236
references 241
chapter 6 piezoresistive sensors 245
6.0 preview 245
6.1 origin and expression of piezoresistivity 245
6.2 piezoresistive sensor materials 248
6.2.1 metal strain gauges 248
6.2.2 single crystal silicon 249
6.2.3 polycrystalline silicon 252
6.3 stress analysis of mechanical elements 252
6.3.1 stress in flexural cantilevers 252
6.3.2 stress and deformation in membrane 258
6.4 applications of piezoresistive sensors 260
6.4.1 inertial sensors 260
6.4.2 pressure sensors 266
6.4.3 tactile sensor 268
6.4.4 flow sensor 271
summary 276
problems 277
references 281
chapter 7 piezoelectric sensing and actuation 283
7.0 preview 283
7.1 introduction 283
7.1.1 background 283
7.1.2 mathematical description of piezoelectric effects 285
7.1.3 cantilever piezoelectric actuator model 287
7.2 properties of piezoelectric materials 290
7.2.1 quartz 290
7.2.2 pzt 292
7.2.3 pvdf 293
7.2.4 zno 294
7.2.5 other materials 298
7.3 applications 299
7.3.1 inertia sensors 299
7.3.2 acoustic sensors 303
7.3.3 tactile sensors 306
7.3.4 flow sensors 307
7.3.5 surface elastic waves 309
summary 311
problems 311
references 315
chapter 8 magnetic actuation 317
8.0 preview 317
8.1 essential concepts and principles 317
8.1.1 magnetization and nomenclatures 317
8.1.3 selected principles of micro magnetic actuators 321
8.2 fabrication of micro magnetic components 326
8.2.1 deposition of magnetic materials 326
8.2.2 design and fabrication of magnetic coil 328
8.3 case studies of mems magnetic actuators 331
summary 342
problems 342
references 344
chapter 9 summary of sensing and actuation methods 346
9.0 preview 346
9.1 comparison of major sensing and actuation methods 346
9.2 other sensing and actuation methods 348
9.2.1 tunneling sensing 348
9.2.3 optical sensing 350
9.2.4 field effect transistors 356
9.2.5 radio frequency resonance sensing 359
summary 360
problems 361
references 362
chapter 10 bulk micromachining and silicon anisotropic etching 365
10.0 preview 365
10.1 introduction 365
10.2 anisotropic wet etching 367
10.2.1 introduction 367
10.2.2 rules of anisotropic etching—simplest case 367
10.2.3 rules of anisotropic etching—complex structures 373
10.2.4 forming protrusions 381
10.2.5 interaction of etching profiles from isolated patterns 381
10.2.6 summary of design methodology 383
10.2.7 chemicals for wet anisotropic etching 385
10.3 dry etching and deep reactive ion etching 390
10.4 isotropic wet etching 391
10.5 gas phase etchants 391
10.6 native oxide 392
10.7 special wafers and techniques 393
summary 393
problems 394
references 400
chapter 11 surface micromachining 403
11.0 preview 403
11.1 basic surface micromachining processes 403
11.1.1 sacrificial etching process 403
11.1.2 micro motor fabrication process—a first pass 404
11.2.3 micro motor fabrication process—a second pass 405
11.1.4 micro motor fabrication process—third pass 406
11.2 structural and sacrificial materials 409
11.2.1 material selection criteria for a two-layer process 409
11.2.2 thin films by low pressure chemical vapor deposition 410
11.2.3 other surface micromachining materials and processes 413
11.3 acceleration of sacrificial etch 414
11.4 stiction and anti-stiction methods 416
summary 417
problems 418
references 420
chapter 12 process synthesis: putting it all together 424
12.0 preview 424
12.1 process for suspension beams 426
12.2 process for membranes 432
12.3 process for cantilevers 437
12.3.1 spm technologies case motivation 437
12.3.2 general fabrication methods for tips 439
12.3.3 cantilevers with integrated tips 441
12.3.4 cantilevers with integrated sensors 446
12.3.5 spm probes with actuators 452
12.4 practical factors affecting yield of mems 457
summary 458
problems 458
references 462
chapter 13 polymer mems 465
13.0 preview 465
13.1 introduction 465
13.2 polymers in mems 467
13.2.1 polyimide 469
13.2.2 su-8 469
13.2.3 liquid crystal polymer (lcp) 470
13.2.4 pdms 471
13.2.5 pmma 473
13.2.6 parylene 473
13.2.7 fluorocarbon 474
13.2.8 other polymers 474
13.3 representative applications 475
13.3.1 acceleration sensors 475
13.3.2 pressure sensors 477
13.3.3 flow sensors 481
13.3.4 tactile sensors 483
summary 486
problems 486
references 487
chapter 14 micro fluidics applications 491
14.0 preview 491
14.1 motivation for microfluidics 491
14.2 essential biology concepts 492
14.3 basic fluid mechanics concepts 495
14.3.1 the reynolds number and viscosity 495
14.3.2 methods for fluid movement in channels 497
14.3.3 pressure driven flow 497
14.3.4 electrokinetic flow 500
14.3.5 electrophoresis and dielectrophoresis 501
14.4 design and fabrication of selective components 503
14.4.1 channels 503
14.4.2 valves 515
summary 518
problems 518
references 520
chapter 15 case studies of selected mems products 525
15.0 preview 525
15.1 case studies: blood pressure (bp) sensor 526
15.1.1 background and history 526
15.1.2 device design considerations 527
15.1.3 commercial case: novasensor bp sensor 528
15.2 case studies: microphone 530
15.2.1 background and history 530
15.2.2 design considerations 531
15.2.3 commercial case: knowles microphone 532
15.3 case studies: acceleration sensors 533
15.3.1 background and history 533
15.3.2 design considerations 533
15.3.3 commercial case: analog devices and memsic 537
15.4 case studies: gyros 538
15.4.1 background and history 538
15.4.2 the coriolis force 538
15.4.3 mems gyro design 540
15.4.4 single axis gyro dynamics 542
15.4.5 commercial case: invensense gyro 544
15.5 summary of top concerns for mems product development 545
15.5.1 performance and accuracy 546
15.5.2 repeatability and reliability 546
15.5.3 managing the cost of mems products 547
15.5.4 market uncertainties, investment, and competition 547
summary 548
problems 548
references 552
appendix 1 characteristics of selected mems materials 553
appendix 2 frequently used formula for beams, cantilevers, and plates 556
appendix 3 basic tools for dealing with a mechanical second-order dynamic system 558
appendix 4 most commonly encountered materials 562
appendix 5 most commonly encountered material removal process steps 563
appendix 6 a list of general compatibility between general materials and processes 564
appendix 7 comparison of commercial inertial sensors 567
answers to selected problems 569
index 571

.　　Evanston, IL
　　September 2010