Post-Processing Techniques for Integrated MEMS

✍ Scribed by Sherif Sedky

• Publisher: Artech House Publishers
• Year: 2005
• Tongue: English
• Leaves: 219
• Category: Library

✦ Synopsis

Sedky (physics, The American University, Cairo, Egypt) investigates the possibility of developing high-quality MEMS structural layers at temperatures compatible with the standard CMOS backend. He first reviews MEMS fabrication technologies, then defines the maximum thermal budget that can be accommodated by prefabricated standard electronics. He highlights the features of different materials suitable for MEMS, and discusses the effect of deposition conditions and the type of substrate on the physical properties of the different materials. Silicon germanium as a MEMS structural layer is also discussed in detail.

✦ Table of Contents

Post-Processing Techniques for Integrated MEMS......Page 1
Contents......Page 6
Preface......Page 10
Acknowledgments......Page 12
1.1 Introduction 1......Page 14
1.2 MEMS Fabrication Technologies 5......Page 18
1.2.1 Bulk Micromachining 6......Page 19
1.2.2 Surface Micromachining 8......Page 21
1.2.3 LIGA 9......Page 22
1.2.4 Deep Reactive Ion Etching 11......Page 24
1.2.5 Soft Lithography 12......Page 25
1.2.6 Laser Micromachining 13......Page 26
1.3 MEMS Monolithic Integration Technology 14......Page 27
1.3.1 Interleaved Processing 15......Page 28
1.3.2 Post-Processing 18......Page 31
References 22......Page 35
2.1 Introduction 31......Page 44
2.2.1 Front-End Description 32......Page 45
2.2.2 Backend Description 34......Page 47
2.2.3 Measurement Setup 36......Page 49
2.3.1 Impact of Annealing Temperature 37......Page 50
2.3.2 Impact of Annealing Period 40......Page 53
2.4 Impact of Annealing Temperature on the Front-End 45......Page 58
2.5 Summary and Conclusions 47......Page 60
References 48......Page 61
3.1 Introduction 51......Page 64
3.2 Stress and Stress Gradient in Thin Films 52......Page 65
3.3 Metals as a MEMS Structural Layer 53......Page 66
3.3.1 Tantalum as an Attractive MEMS Material 54......Page 67
3.3.2 Nickel for MEMS Applications 61......Page 74
3.3.3 Platinum as a MEMS Material 63......Page 76
3.3.4 Gold as a MEMS Material 66......Page 79
3.3.5 Electroplated Copper......Page 80
3.4 Semiconductor and Dielectric Materials 69......Page 82
3.4.1 Polycrystalline Silicon......Page 83
3.4.2 Polycrystalline Germanium 72......Page 85
3.4.3 Silicon Nitride 73......Page 86
3.4.4 Silicon Dioxide 76......Page 89
3.4.5 Porous Silicon 78......Page 91
3.4.6 Silicon Carbide 79......Page 92
3.5 Summary and Conclusion 80......Page 93
References......Page 96
4.1 Introduction 91......Page 104
4.2 Actual Wafer Temperature 93......Page 106
4.3 Growth Kinetics of Silicon Germanium 94......Page 107
4.4 Conduction Mechanism in Polycrystalline Silicon Germanium 99......Page 112
4.5 Electrical Properties of Polycrystalline Silicon Germanium 101......Page 114
4.5.1 Characteristics of Ion-Implanted Polycrystalline Silicon Germanium 102......Page 115
4.5.2 Characteristics of In Situ Doped Polycrystalline Silicon Germanium 107......Page 120
4.6 Electrical Noise in Polycrystalline Silicon Germanium 110......Page 123
4.7 Thermal Properties of Silicon Germanium 114......Page 127
4.8 Stress in Polycrystalline Silicon Germanium 116......Page 129
4.8.1 Effect of Deposition Conditions and Annealing Temperature 117......Page 130
4.8.2 Impact of Reducing the Deposition Temperature 118......Page 131
4.8.3 Stress in PECVD Silicon Germanium 120......Page 133
4.9 Stress Gradient in Silicon Germanium 121......Page 134
4.9.1 Effect of Thermal Treatment and Doping Type on Stress Gradient 122......Page 135
4.9.2 Effect of Deposition Conditions and Ge Content on Stress Gradient 124......Page 137
4.10 Summary and Conclusion 128......Page 141
References......Page 143
5.1 Introduction 135......Page 148
5.2 Metal Induced Crystallization of SiGe 136......Page 149
5.2.1 MIC for MEMS Application 138......Page 151
5.3 Laser Induced Crystallization 144......Page 157
5.3.2 Effect of Laser Annealing on Grain Microstructure, Electrical Conductivity,
and Surface Roughness 145......Page 158
5.3.3 Film Melt Depth 149......Page 162
5.3.4 Effect of Laser Annealing on Mean Stress and Stress Gradient 153......Page 166
5.4 Summary and Conclusion 157......Page 170
References 159......Page 172
6.1 Introduction 163......Page 176
6.2.1 Monolithic Integration of DMDs 164......Page 177
6.2.2 Monolithic Integration of Surface Micromachined Accelerometers......Page 181
6.3 Monolithic Integration Using Bulk Micromachining and DRIE......Page 199
6.4 Summary and Conclusion......Page 202
References......Page 203
List of Acronyms 197......Page 210
About the Author......Page 214
Index......Page 215