Zheng Cui Micro-Nanofabrication TECHNOLOGIES AND APPLICATIONS ^f**"?* ö Springer Higher Education Press -T O
Table of Content Preface About the Author Chapter 1 Introduction 1 1.1 Micro-nanotechnologies and micro-nanofabrication technologies 1 1.2 Classification of micro-nanofabrication technologies 3 1.3 Organisation ofthebook 8 References 11 Chapter 2 Optical Lithography 13 2.1 Principle of optical lithography 15 2.2 Process of optical lithography 23 2.3 Characteristics ofphotoresists 25 2.3.1 Common features ofphotoresists 26 2.3.2 Comparison of positive and negative photoresists 30 2.3.3 Chemically amplified resists 32 2.3.4 Special photoresists 33 2.4 Design and fabrication of photomasks 33 2.5 Resolution enhancement techniques 37 2.5.1 Off-axis Illumination 38 2.5.2 Spatial filtering 38 2.5.3 Phase shift masks 40 2.5.4 Optical proximity correction 45 2.6 The limit of optical lithography 47 2.7 Optical lithography ofthick photoresists 49 2.7.1 Conventional thick photoresist 50 2.7.2 SU-8 photoresist 51 2.8 Grey-scale photolithography 56 2.9 Computer Simulation of optical lithography 61 2.9.1 Theory of partial coherent imaging 62 2.9.2 Computer Simulation Software COMP ARE 66 2.9.3 Comparing the quality of optical lithography 67 References 74
viii Table of Content Chapter 3 Electron Beam Lithography 77 3.1 Principle of electron optics 78 3.2 Electron beam lithography Systems 85 3.2.1 Vector scan and raster scan Systems 88 3.2.2 Shaped beam Systems 93 3.2.3 Projection lithography Systems 94 3.2.4 Microcolumn e-beam lithography Systems 96 3.3 Pattern design and data format for e-beam lithography 98 3.3.1 Issues in pattern design 98 3.3.2 Intermediäre data format 100 3.3.3 AutoCAD format 102 3.3.4 Machine data format 103 3.4 Electron beam resists and processes 105 3.4.1 High resolution e-beam resists 106 3.4.2 Chemically amplified resists 109 3.4.3 Multilayer resists process 114 3.5 Electron scattering and proximity effect 116 3.5.1 Electron scattering in solid materials 116 3.5.2 Proximity effect in e-beam lithography 122 3.5.3 Approximation of point spread function 123 3.6 Correction of proximity effect 124 3.7 Computer Simulation of e-beam lithography 129 3.8 Ultimate resolution of e-beam lithography 131 3.8.1 E-beam lithography System 131 3.8.2 Secondary electron scattering effect 133 3.8.3 Resist process 133 References 135 Chapter 4 Focused Ion Beam Technology 139 4.1 Liquid metal ion sources 139 4.2 Focused ion beam Systems 143 4.3 Ion scattering in solid materials 145 4.4 Principle of focused ion beam processing 148 4.4.1 Ionsputtering 148 4.4.2 Ion beam assisted deposition 151 4.5 Applications of FIB technology 152 4.5.1 Inspecting and editing integrated circuits 152 4.5.2 Repairing defects of optical masks 154 4.5.3 Preparing TEM samples 158 4.5.4 A versatile microfabrication tool 159 4.6 Focused ion beam lithography 162 4.7 Focused ion beam implantation 165 References 166
Table of Content ix Chapter 5 X-ray Lithography 169 5.1 Principle of X-ray lithography 170 5.2 X-ray lithography System 175 5.2.1 X-ray source 175 5.2.2 X-ray maskaligner and stepper 178 5.2.3 X-ray mask 179 5.2.4 X-ray resists 182 5.3 High resolution X-ray lithography 182 5.4 High aspect ration X-ray lithography (LIGA technology) 184 5.4.1 X-ray source 187 5.4.2 LIGA mask 187 5.4.3 Thick resists and processes for LIGA 189 5.4.4 Accuracy of LIGA patterning 192 References 195 Chapter 6 Etching Technology 197 6.1 Wet chemical etching 197 6.1.1 Anisotropie wet etching of Silicon 198 6.1.2 Isotropie etching of Silicon 205 6.1.3 Isotropie etching of Silicon dioxide 207 6.2 Dry etching 1: reactive ion etching 209 6.3 Dry etching 2: deep reactive ion etching 216 6.4 Dry etching 3: ion sputtering etching 221 6.5 Dry etching 4: reactive gas etching 223 6.6 Dry etching 5: other physical etching techniques 225 6.6.1 Laser micromachining 225 6.6.2 Electrodischarge micromachining 229 6.6.3 Powder blasting 230 References 234 Chapter 7 Replication Technology 237 7.1 Nanoimprint lithography 237 7.2 Step and flash nanoimprinting lithography 243 7.3 Soft lithography...245 7.4 Micromoulding ofplastics 247 7.4.1 Hot embossing 248 7.4.2 Micro inj ection moulding 250 7.4.3 Casting 253 7.5 Microstereolithography 255 7.6 Other replication techniques 258 7.6.1 DipPen nanolithography 258 7.6.2 Nanosphere lithography 260 7.6.3 Nanostencil lithography 262 References 264
x Table of Content Chapter 8 Applications of Micro-nanofabrication Technologies 267 8.1 Very large scale integrated circuits 267 8.2 Nanoelectronics 273 8.3 Optoelectronics 276 8.4 High density magnetic storage 278 8.5 Micro-electro-mechanical Systems 282 8.6 Biochips 289 8.7 Nanotechnology 294 References 297 Index 301