Technology. Semiconductor Manufacturing. Hong Xiao INTRODUCTION TO SECOND EDITION SPIE PRESS

Transcription

1 INTRODUCTION TO Semiconductor Manufacturing Technology SECOND EDITION Hong Xiao TECHNISCHE INFORMATIONSBiBUOTHEK UNIVERSITATSBIBLIOTHEK HANNOVER SPIE PRESS Bellingham,Washington USA

2 Contents Preface to the First Edition xxi Preface to the Second Edition List of Acroynms xxiii xxv Chapter 1 Introduction Brief History of Integrated Circuits First transistor First integrated circuit Moore's law Feature and wafer size Definition of the integrated circuit technology node Moore's law or the law of more Brief Overview of Integrated Circuits Manufacturing materials Processing equipment Metrology tools Wafer manufacturing Circuit design Mask formation Wafer processing Summary Bibliography Review Questions 21 Chapter 2 Introduction to Integrated Circuit Fabrication Introduction Yield Definition of yield Yield and profit margin Defects and yield Cleanroom Basics Definition of a cleanroom 29 vii

3 viii Contents Contamination control and yield Basic cleanroom structure Basic cleanroom gowning procedures Basic cleanroom protocols 2.4 Basic Structure of an Integrated Circuit Fabrication Facility Wafer processing area Wet bay Diffusion bay Photo bay Etch bay Implant bay Thin-film bay Chemical mechanical polishing bay Equipment area Facility area Testing and Packaging Die testing Chip packaging Final test D packaging 2.6 Future Trends 2.7 Summary 2.8 Bibliography 2.9 Review Questions Chapter 3 Semiconductor Basics What Is a Semiconductor? Bandgap Crystal structure Doping semiconductor Dopant concentration and conductivity Summary of semiconductors Basic Devices Resistor Capacitor Diode Bipolar transistor Metal-oxide-semiconductor field effect transistor Integrated Circuit Chips Memory Dynamic random access memory Static random access memory Erasable programmable read-only memory, electric erasable programmable read-only mem ory, and flash 76

4 Contents _jx Microprocessor Application-specific integrated circuits Basis Integrated Circuit Processes Conventional bipolar transistor process p-channel metal-oxide-semiconductor process (1960s technology) n-channel metal-oxide-semiconductor process (1970s technology) Complementary Metal-Oxide Semiconductor Complementary metal-oxide-semiconductor circuit Complementary metal-oxide-semiconductor circuit pro cess (1980s technology) Complementary metal-oxide-semiconductor process (1990s technology) Technology Trends after Summary Bibliography Review Questions 93 Chapter 4 Wafer Manufacturing, Epitaxy, and Substrate Engineering Introduction Why Silicon? Crystal Structures and Defects Crystal orientation Crystal defects Sand to Wafer Crude silicon Silicon purification Crystal pulling Czochralski method Floating zone method Wafering Wafer finishing Epitaxial Silicon Deposition Gas phase epitaxy Epitaxial growth process Epitaxy hardware Epitaxy process Future trends of epitaxy Selective epitaxy Substrate Engineering Silicon-on-insulator wafer Hybrid orientation technology Strained silicon wafer 119

5 x Contents Strained silicon-on-insulator wafer Strained silicon in integrated circuit manufacturing Summary Bibliography Review Questions 122 Chapter 5 Thermal Processes Introduction 5.2 Thermal Process Hardware Introduction Control system Gas delivery system Loading system Exhaust system Processing tube 5.3 Oxidation Applications Preoxidation cleaning Oxidation rate Dry oxidation Wet oxidation High-pressure oxidation Oxide measurement Recent oxidation trends 5.4 Diffusion Deposition and drive-in Doping measurement 5.5 Annealing Postimplantation annealing Alloy annealing Reflow 5.6 High-Temperature Chemical Vapor Deposition Epitaxial silicon deposition Selective epitaxial growth processes Polycrystalline silicon deposition Silicon nitride deposition Rapid Thermal Processing Rapid thermal annealing Rapid thermal oxidation Rapid thermal chemical vapor deposition Recent Developments Summary Bibliography Review Questions

6 Contents x Chapter 6 Photolithography Introduction Photoresist Photolithography Process Wafer cleaning Preparation Photoresist coating Soft bake Alignment and exposure Contact and proximity printers Projection printer Stepper/scanner Exposure light sources Exposure control Postexposure bake Development Hard bake Metrology and defect inspection Track-stepper integration system Lithographic Technology Trends Resolution and depth of focus Mercury lamps and excimer lasers Resolution enhancement techniques Phase shift mask Optical proximity correction Off-axis illumination Immersion lithography Double, triple, and multiple patterning Extreme-ultraviolet lithography Nanoimprint lithography X-ray lithography Electron beam lithography Ion beam lithography Safety Summary Bibliography Review questions 235 Chapter 7 Plasma Basics Introduction Definition of Plasma Components of plasma Generation of plasma 238

7 Xjj Contents 7.3 Collisions in Plasma Ionization Excitation-relaxation Dissociation Other collisions 7.4 Plasma Parameters Mean free path Thermal velocity Magnetic field Boltzmann distribution Ion Bombardment 7.6 Direct-Current Bias 7.7 Advantage of Plasma Processes Chemical vapor deposition Plasma-enhanced chemical vapor deposition Stress control Chamber cleaning Gap fill Plasma etch Etch profile control Etch rate and selectivity Endpoint Chemical use Sputtering deposition Plasma-Enhanced Chemical Vapor Deposition and Plasma Etch Chambers Processing differences Chemical vapor deposition chamber design Etch chamber design Remote Plasma Processes Photoresist strip Remote plasma etch Remote plasma cleaning Remote plasma chemical vapor deposition High-Density Plasma Inductively coupled plasma Electron cyclotron resonance 7.11 Summary 7.12 Bibliography Review Questions Chapter 8 Ion Implantation Introduction Brief history 267

8 Contents *!!> Advantages of implantation Applications Ion Implantation Basics Stopping mechanisms Ion range Channeling effect Damage and annealing Ion Implantation Hardware Gas system Electrical system Vacuum system Control system Beam line system Ion source Extraction system Mass analyzer Postacceleration Charge neutralization system Wafer handler Beam stop Ion Implantation Process Device applications Other ion implantation applications Processing issues Wafer charging Particle contamination Elemental contamination Process evaluation Secondary ion mass spectroscopy Four-point probe Thermal wave Optical-electrical sheet resistance measurement Safety Chemical hazards Electrical hazards Radiation hazards Mechanical hazards Recent Developments and Applications Summary Bibliography Review Questions Chapter 9 Etch Introduction 315

9 xiv Contents 9.2 Etch Basics Etch rate Uniformity Selectivity Profile Etch bias Loading effects Macroloading Microloading Overetch Residue Wet Etch Process Introduction Oxide wet etch Silicon etch Nitride etch Metal etch Plasma (Dry) Etch Introduction Plasma review Chemical, physical, and reactive ion etches Etch mechanisms Plasma etch chamber Endpoint Plasma Etch Processes Dielectric etch Single-crystal silicon etch Polysilicon etch Metal etch Photoresist strip Dry chemical etch processes Blanket dry etch processes Plasma etch safety Process Trends 9.7 Recent Developments Summary Bibliography Review Questions Chapter 10 Chemical Vapor Deposition and Dielectric Thin Films Introduction 10.2 Chemical Vapor Deposition Chemical vapor deposition process description

10 Contents xv Chemical vapor deposition reactor types Atmospheric pressure chemical vapor deposition Low-pressure chemical vapor deposition Plasma-enhanced chemical vapor deposition Chemical vapor deposition basics Step coverage Gap fill Surface adsorption Chemisorption Physisorption Chemical vapor deposition precursors and their adsorption Sticking coefficient Chemical vapor deposition kinetics Chemical reaction rate Surface-reaction-limited regime Mass-transport-limited regime Chemical vapor deposition reactor deposition regime Applications of Dielectric Thin Films Shallow trench isolation Sidewall spacer Interlayer dielectric Interlayer dielectric-1 and up Passivation dielectrics Dielectric thin-film characteristics Refractive index Ellipsometry Prism coupler Thickness Color chart Spectroreflectometry Deposition rate Wet etch rate Shrinkage Uniformity Stress Dielectric Chemical Vapor Deposition Processes Thermal silane chemical vapor definition process Thermal tetraethoxysilane chemical vapor deposition process Plasma-enhanced chemical vapor deposition silane process Passivation Interlayer dielectric-0 barrier layer Dielectric antireflective coating 415

11 XVj Contents Plasma-enhanced chemical vapor deposition tetraethoxysilane process Dielectric etchback process Ozone-tetraethoxysilane process Ozonator Ozone-tetraethoxysilane undoped silicate glass process Ozone-tetraethoxysilane phosphosilicate glass 10.6 Spin-On Glass and borophosphosilicate glass processes High-Density Plasma Chemical Vapor Deposition Dielectric Chemical Vapor Deposition Chamber Cleaning Radio-frequency plasma cleaning Remote plasma cleaning Process Trends and Troubleshooting Silane plasma-enhanced chemical vapor deposition processing trends Plasma-enhanced tetraethylorthosilicate trends Ozone-tetraethoxysilane trends Troubleshooting guide Recent Developments Low-K dielectrics Air gap Atomic layer deposition High-K dielectrics Summary Bibliography Review Questions 449 Chapter 11 Metallization Introduction Conducting Thin Films Polysilicon Silicides Aluminum Titanium Titanium nitride Tungsten Copper Tantalum Cobalt Nickel 465

12 Contents 11.3 Metal Thin-Film Characteristics Thickness and deposition rate Uniformity Stress Reflectivity Sheet resistance Metal Chemical Vapor Deposition Introduction Tungsten Tungsten silicide Titanium Titanium nitride Aluminum Physical Vapor Deposition Introduction Evaporation processes Thermal evaporation Electron beam evaporation Sputtering Basic metallization processes Degas Preclean Titanium physical vapor deposition Titanium nitride physical vapor deposition Aluminum-copper physical vapor deposition Copper Metallization Precleaning Barrier layer Copper seed layer Copper electrochemical plating Copper chemical vapor deposition Safety Summary Bibliography Review Questions 505 Chapter 12 Chemical Mechanical Polishing Introduction Overview Definition of planarization Other planarization methods Necessity of chemical mechanical polishing Advantages of chemical mechanical polishing Applications of chemical mechanical polishing 516

13 xviii Contents 12.2 Chemical Mechanical Polishing Hardware Introduction Polishing pad Polishing head Pad conditioner 12.3 Chemical Mechanical Polishing Slurries Oxide slurry Metal polishing slurry Tungsten slurry Aluminum and copper slurries 12.4 Chemical Mechanical Polishing Basics Removal rate Uniformity Selectivity Defects Chemical Mechanical Polishing Processes Oxide chemical mechanical polishing Tungsten chemical mechanical polishing Copper chemical mechanical polishing Chemical mechanical polishing endpoint detection Post-chemical-mechanical-polishing wafer cleaning Process issues 12.6 Recent Developments Summary Bibliography Review Questions Chapter 13 Process Integration Introduction Wafer Preparation Isolations Blanket field oxide Local oxidation of silicon Shallow trench isolation Self-aligned shallow trench isolation 557 Well Formation Single well Self-aligned twin wells Twin wells 559 Transistor Formation Metal gate process Self-aligned source/drain process Lightly doped drain Threshold adjustment Anti-punch-through

14 Contents xjx 13.6 Metal-Oxide-Semiconductor Field-Effect Transistors with Highk and Metal Gates Gate-first process Gate-last process Hybrid high-k metal gates Interconnections Local interconnections Early interconnections Aluminum alloy multilevel interconnections Copper interconnections Copper and 1ow-k dielectrics Passivation Summary Bibliography Review Questions 580 Chapter 14 Integrated Circuit Processing Technologies Introduction Complementary Metal-Oxide-Semiconductor Process Flow of the Early 1980s Complementary Metal-Oxide-Semiconductor Process Flow with 1990s Technology Comments Complementary Metal-Oxide-Semiconductor Process Flow with Technology after Complementary Metal-Oxide-Semiconductor Process Flow with Technology after Memory Chip Manufacturing Processes Dynamic random access memory process flow Stacked dynamic random access memory process flow NAND flash process Summary Bibliography Review Questions 648 Chapter 15 Future Trends and Summary Bibliography 655 Index 657