Chapter 1 Introduction 1
1.1 Concept of MEMS 1
1.2 Development of MEMS 4
1.3 MEMS CAD 9
Chapter 2 Basic theory of MEMS 12
2.1 Theory of electrostatic MEMS comb actuators 12
2.1.1 Introduction 12
2.1.2 Operating principles 13
2.1.3 Plate capacitor theory in ideal condition 14
2.1.4 The modified model of MEMS plate capaciator 17
2.1.5 Calculation of electrostatic comb driving force in ideal situation 24
2.1.6 Weak capacitance detection method of electrostatic comb drive 26
2.2 Relevant theoretical calculations for the MEMS cantilever beam 34
2.2.1 Introduction 34
2.2.2 Theoretical calculation method for cantilever beam 35
2.2.3 Relevant theoretical calculation of axial tensile and compressive on single-end clamped beams 36
2.2.4 Related theoretical calculations of double-end clamped beams axial tension and compression 40
2.3 Membrane theory of MEMS 47
2.3.1 Theory of clamped around circular diaphragm 48
2.3.2 Theory of clamped around rectangular flat diaphragm 49
References 52
Chapter 3 MEMS materials 53
3.1 Monocrystalline silicon 53
3.1.1 Introduction 53
3.1.2 Crystal orientation of monocrystalline silicon 55
3.2 Polycrystalline silicon 64
3.3 Silica 66
3.4 Piezoelectric materials 67
3.4.1 Piezoelectric effect and inverse piezoelectric effect of materials 67
3.4.2 Quartz crystal 68
3.4.3 Piezoelectric ceramics 73
3.5 Other MEMS materials 75
3.6 Summary 76
Chapter 4 MEMS technology 77
4.1 MEMS lithography process 78
4.2 Key technology of MEMS lithography process 80
4.2.1 Wafer cleaning 80
4.2.2 Silicon oxidation 80
4.2.3 Spin coating process 87
4.2.4 Prebaking 90
4.2.5 Exposure 92
4.2.6 Development 94
4.2.7 Hardening 96
4.2.8 Fabrication of the SiO2 window 97
4.3 Subsequent process of MEMS 98
4.3.1 Bulk silicon technology 98
4.3.2 Surface silicon process 103
4.3.3 LIGA technology 104
4.3.4 Sputtering technology 105
4.3.5 Lift-off process 107
4.4 Film preparation technology 107
4.5 Bonding process 108
4.5.1 Anodic bonding process 109
4.5.2 Silicon-silicon direct bonding 110
4.5.3 Metal eutectic bonding 113
4.5.4 Cold pressure welding bonding 114
4.6 Engineering examples of combination for multiple processes to fabricate the MEMS device 115
4.6.1 Introduction 115
4.6.2 Engineering example of fabrication process for resonant MEMS gyroscope 115
4.6.3 Engineering example of electromagnetic micro-motor production process 118
4.7 Summary 124
References 125
Chapter 5 Friction wear and tear under micro scale 126
5.1 Off-chip testing method for micro friction 127
5.1.1 Micro-tribology test with the pin-on-disc measuring method 127
5.1.2 Micro-tribology test with AFM 128
5.1.3 Micro-tribology test with special measuring device 130
5.2 On-chip testing method for micro friction 132
5.2.1 On-chip testing method actuated by electrostatic force 132
5.2.2 On-chip micro-friction testing method using the mechanism characters of the bimorph material 139
5.3 Example of the design for an on-chip micro-friction structure 141
5.3.1 Structure and working principle 141
5.3.2 Calculation of pertinent theory 142
5.3.3 Technological analysis of structural design 148
5.3.4 Testing results and data analysis 152
5.3.5 Research and test of wear problem of MEMS devices 161
5.4 Summary 165
References 165
Chapter 6 MEMS testing technology and engineering application 169
6.1 Acceleration measurement and corresponding sensors 169
6.1.1 Working principle of the acceleration sensor and the classification 170
6.1.2 Capacitive silicon micromechanical accelerometer 172
6.1.3 Piezoresistive silicon micromechanical aceelerometer 173
6.1.4 Piezoelectric micromechanical accelerometer 174
6.1.5 Resonant silicon MEMS accelerometer 175
6.2 Angular speed measurement and corresponding sensors 177
6.2.1 Working principle 177
6.2.2 Development of MEMS gyroscope 178
6.2.3 Classification of micromechanical gyroscope 188
6.3 Pressure measurement and corresponding sensors 190
6.3.1 Working pincinple 190
6.3.2 Resonant silicon micromechanical pressure sensor and its development 193
6.4 Measurement of micro-torque 198
6.4.1 Introduction 198
6.4.2 Working principle of noncontact method 199
6.4.3 Theoretical calculation 200
6.4.4 Corresponding equipment to realize the noncontact method 205
6.4.5 Experiment result and discussion 209
6.5 Microscopic morphology testing method 211
6.6 Summary 212
References 212
Chapter 7 Application examples of the finite element method in the design of MEMS devices 218
7.1 Important concepts of the software 218
7.2 Introduction of the Ansys software interface 220
7.3 The coordinate system in Ansys 221
7.4 Engineering examples 226
7.4.1 Static analysis of single-clamped beam 226
7.4.2 Modal analysis of double-clamped beam 245
7.4.3 Capacitance analysis of MEMS electrostatic comb fingers drive 257
7.4.4 Fatigue strength calculation example 264
7.5 Summary 272