Nanofabrication (eBook)

Zheng Cui, PhD, is a professor at and Director of the Department of Printed Electronics at the Suzhou Institute of Nanotech and Nanobionics, Chinese Academy of Sciences. He received his PhD from Southeast University in Nanjing, China, and has been a Visiting Fellow at the Microelectronics Research Center at Cambridge University, as well as a Senior Scientist and Principal Scientist at Central Microstructure Facility in Rutherford Appleton Laboratory.

Preface 5
Preface to the First Edition 8
Contents 11
Chapter 1: Introduction 16
1.1 What Is Nanofabrication 16
1.2 Classification of Nanofabrication 18
1.3 Purpose of the Book 21
Chapter 2: Nanofabrication by Photons 23
2.1 Introduction 23
2.2 Principle of Optical Projection Lithography 24
2.3 Basics of Photoresists 29
2.3.1 Process of Optical Lithography 29
2.3.2 Characteristics of Photoresists 31
2.4 Optical Lithography at Shorter Wavelengths 35
2.4.1 Deep UV 35
2.4.2 Extreme UV 37
2.4.2.1 EUV Source 38
2.4.2.2 EUV Optics 38
2.4.2.3 EUV Mask 39
2.4.2.4 EUV Resists 40
2.4.3 X-Ray 41
2.5 Optical Lithography at High NA 44
2.6 Optical Lithography at Low k1 Factor 51
2.6.1 Off-Axis Illumination (OAI) 55
2.6.2 Phase-Shifting Mask (PSM) 56
2.6.3 Optical Proximity Correction (OPC) 61
2.6.4 Photoresists 66
2.6.4.1 Sensitivity 67
2.6.4.2 Contrast 68
2.6.4.3 Line Edge Roughness (LER) 71
2.6.4.4 Etch Resistance 73
2.6.5 Design for Manufacturing (DFM) 76
2.6.6 Double Processing 77
2.7 Near-Field Optical Lithography 81
2.8 Talbot Optical Lithography 87
2.9 Interferometric Optical Lithography 88
2.10 Maskless Optical Lithography 93
2.11 Two-Photon Polymerization Lithography 97
References 100
Chapter 3: Nanofabrication by Electron Beam 105
3.1 Introduction 105
3.2 Principle of Electron Optics 107
3.2.1 Electron Lens 107
3.2.2 Electron Source 111
3.2.3 Aberrations 113
3.3 Electron Beam Lithography Systems 117
3.3.1 Basic Configuration 117
3.3.2 Key Specifications 119
3.3.3 Vector and Raster Scanning 120
3.3.4 Pattern Fragmentation 121
3.3.5 Commercial e-Beam Lithography Systems 123
3.4 Scattering and Proximity Effect 124
3.4.1 Electron Scattering 125
3.4.2 Proximity Effect and Correction 129
3.4.3 Effect of Secondary Electrons 136
3.4.4 Low Energy e-Beam Lithography 138
3.5 Resist Materials and Processes 141
3.5.1 Sensitivity of Resist Materials 142
3.5.2 Contrast of Resist Materials 147
3.5.3 Resolution Enhancement Processes 149
3.6 Conditions for High Resolution e-Beam Lithography 153
3.7 High-Throughput e-Beam Lithography 154
3.7.1 Shaped Beam Lithography 155
3.7.2 Mask Projection Lithography 155
3.7.3 Multi e-Beam Lithography 157
References 158
Chapter 4: Nanofabrication by Ion Beam 163
4.1 Introduction 163
4.2 Liquid Metal Ion Sources 163
4.3 Focused Ion Beam Systems 167
4.4 Ion Scattering in Solid Materials 169
4.5 FIB Direct Nanofabrication 172
4.5.1 Ion Sputtering 172
4.5.2 Ion Beam Assisted Deposition 176
4.5.3 Applications 178
4.5.3.1 Inspecting and Editing Integrated Circuits 178
4.5.3.2 Repairing Defects of Optical Masks 180
4.5.3.3 Preparing TEM Samples 182
4.5.3.4 Nanostructuring for Scientific Research 183
4.6 Focused Ion Beam Lithography 183
4.7 Ion Projection Lithography 186
References 187
Chapter 5: Nanofabrication by Scanning Probes 190
5.1 Introduction 190
5.2 Principles of Scanning Probe Microscopes 191
5.3 Exposure of Resists 194
5.3.1 Field Electron Emission 194
5.3.2 Exposure of Resist by STM 196
5.3.3 Exposure of Resist by NSOM 200
5.4 Local Oxidation Lithography 201
5.5 Additive Nanofabrication 204
5.5.1 Field Induced Deposition 204
5.5.2 Dip-Pen Nanolithography 206
5.6 Subtractive Nanofabrication 208
5.6.1 Electrochemical Etching 208
5.6.2 Field Induced Decomposition 209
5.6.3 Thermomechanical Indentation 210
5.6.4 Mechanical Scratching 211
5.7 High Throughput Scanning Probe Lithography 214
References 218
Chapter 6: Nanofabrication by Replication 221
6.1 Introduction 221
6.2 Thermal Press Nanoimprint 223
6.2.1 Nanoimprint Stamps 225
6.2.2 Nanoimprint Polymers 226
6.2.3 Demolding 231
6.2.4 Alignment 233
6.3 Room-Temperature Nanoimprint 236
6.4 UV-Cured Nanoimprint 238
6.4.1 Transparent Stamps 239
6.4.2 UV-Curable Polymers 243
6.4.3 Step and Flash Imprint Lithography 245
6.4.4 Alignment Through Transparent Stamps 248
6.4.5 Combined Nanoimprint and Photolithography 251
6.5 Reverse Nanoimprint 253
6.6 Soft Lithography 258
6.6.1 Soft Stamps 259
6.6.2 Microcontact Printing 262
6.6.3 Replication by Capillary Force 264
6.7 Roll-to-Roll Continuous Nanoimprint 268
References 273
Chapter 7: Nanoscale Pattern Transfer by Etching 279
7.1 Introduction 279
7.2 Wet Chemical Etching 281
7.2.1 Wet Isotropic Etching 281
7.2.2 Wet Anisotropic Etching 283
7.2.3 Metal-Assisted Anisotropic Etching 287
7.3 Reactive Ion Etching (RIE) 289
7.3.1 Principle of RIE 289
7.3.2 Process Control in RIE 293
7.3.3 RIE by Inductively Coupled Plasma 300
7.3.4 Critical Issues in RIE 305
7.4 Ion Milling 310
References 314
Chapter 8: Nanoscale Pattern Transfer by Deposition 317
8.1 Introduction 317
8.2 Thin Film Deposition 317
8.2.1 Long-Throw Deposition 323
8.2.2 Collimated Deposition 323
8.3 Pattern Transfer by Lift-Off 324
8.4 Pattern Transfer by Plating 330
8.5 Pattern Transfer by Stencil Mask 336
8.6 Pattern Formation by Printing 340
References 343
Chapter 9: Indirect Nanofabrication 346
9.1 Introduction 346
9.2 Sidewall Lithography 347
9.3 Dimensional Subtraction and Addition 351
9.3.1 Lateral Subtraction 351
9.3.2 Lateral Addition 357
9.3.3 Vertical Subtraction 360
9.4 Nanosphere Lithography 363
9.5 Multistep Processing 366
9.6 Super Resolution Patterning 368
References 373
Chapter 10: Nanofabrication by Self-Assembly 376
10.1 Introduction 376
10.2 Self-Assembly Processes 377
10.2.1 Molecular Self-Assembly 379
10.2.2 Self-Assembly of Colloidal Particles 382
10.3 Guided Self-Assembly 387
10.3.1 Surface Topography 387
10.3.2 Surface Energy 388
10.3.3 Electrostatic Force 390
10.3.4 Magnetic Force 392
10.3.5 Thermal Energy 394
10.4 Block Copolymers 395
10.4.1 Controlled Microphase Separation 396
10.4.2 Applications of Block Copolymers 397
10.4.3 Practical Issues 399
10.5 Porous Alumina 402
References 407
Chapter 11: Applications of Nanofabrication Technologies 411
11.1 Introduction 411
11.2 Nanoelectronics 412
11.3 Optoelectronics 419
11.4 High-Density Magnetic Storage 424
11.5 Nanotechnology 427
References 433
Index 437