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| Contributors | |
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| Foreword | |
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| Preface | |
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| Introduction | |
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| Overview | |
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| EUVL History | |
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| Applications | |
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| Photomasks | |
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| Glass Substrate | |
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| Multilayer Mirror | |
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| Capping Layer | |
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| Absorber Layer | |
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| Defect Mitigation and Handling Strategy | |
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| Resist Films | |
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| RLS Triangle | |
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| Outgassing | |
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| Exposure | |
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| Source-Collector Module (SoCoMo) | |
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| Debris Mitigation | |
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| Printing | |
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| Shadowing and Flare Compensation | |
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| Resolution-Enhancement Techniques (RETs) | |
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| Future Enhancements | |
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| References | |
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| Exposure System | |
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| Introduction: Extreme Ultraviolet Lithography (EUVL), Extension of Optical Lithography | |
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| Overview of Optical Lithography | |
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| Optical Fundamentals for Lithography | |
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| Benefits of EUVL | |
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| EUVL-Specific Challenges | |
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| Introduction | |
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| Source | |
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| Vacuum | |
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| Reflective Optics | |
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| Mask Defects | |
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| Mask Nontelecentricity | |
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| Flare | |
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| Mechanics | |
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| EUVL System Performance Predictions | |
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| Introduction | |
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| Optical Transfer Function (OTF) Modeling | |
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| Process Window Modeling | |
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| Mask Shadowing | |
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| EUVL Systems Overview | |
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| Introduction | |
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| Overview of the ETS | |
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| Overview of the ASML Alpha Demo Tool | |
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| Detailed Analysis and Performance Characterization of an EUVL Microstepper | |
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| Introduction | |
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| MET System Overview | |
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| MET Predicted Resolution Limit | |
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| Tool Characterization | |
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| Pupil-Fill Control in EUVL | |
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| Introduction | |
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| Benefits of Pupil-Fill Control | |
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| Pupil-Fill Control Methods in EUVL | |
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| Demonstration of Modified Illumination in EUVL | |
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| Flare | |
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| Introduction | |
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| Computing/Predicting Flare | |
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| Measuring Flare | |
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| Optical Components for EUVL | |
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| Grating-Based High-Efficiency Spectral-Purity Filter | |
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| Diffractive Optical Elements for Pupil-Fill Control | |
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| References | |
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| EUV Sources | |
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| Introduction | |
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| History of Sources in the EUV Region | |
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| Considerations from Early Source Studies for EUVL | |
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| Early Discharge-and Laser-Produced Plasma Concepts | |
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| Current Directions of Development | |
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| Current EUVL Roadmap Requirements | |
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| EUV Radiation Characteristics | |
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| Lifetime and Stability | |
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| EUV Light Generation and Overall Efficiency | |
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| Footprint and Cost of Ownership | |
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| DPP Sources | |
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| Theoretical Background for Discharge Plasmas | |
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| The Dense-Plasma-Focus EUV Source | |
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| The Hollow-Cathode Pinch-Plasma Source | |
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| The Z-Pinch-Plasma Source | |
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| Star-Pinch-Plasma EUV Source | |
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| Capillary-Discharge Sources | |
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| EUV Collectors for DPP Sources | |
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| Debris-Mitigation Schemes for DPP Sources | |
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| Laser-Plasma Sources | |
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| Physics of Laser-Plasma EUV Sources | |
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| Spectral Emission from Tin | |
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| Computer Code Modeling of Plasma and Radiation | |
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| Laser-Plasma Source Architectures | |
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| EUV Conversion Efficiency | |
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| Particle, Neutral-Atom, and Ion Debris | |
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| Debris Mitigation for Laser-Plasma Sources | |
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| EUV Collection Optics for LPP Sources | |
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| Future Trends | |
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| Integrated Sources Using Laser Plasmas | |
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| Pushing for More Power | |
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| Changes in Source Technologies | |
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| References | |
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| EUV Optics | |
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| Introduction | |
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| Lithography Using 13.5-nm Light | |
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| Optical Properties in the EUV Spectral Range | |
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| EUV Optical Components | |
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| Optical Designs | |
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| Condensers and Illuminators | |
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| Basic Imaging System Requirements | |
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| Projection Optics for Microsteppers | |
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| Projection Optics-Scanners with NA<0.25 | |
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| Projection Optics-Scanners with NA≥ 0.25 | |
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| Optics Fabrication and Metrology | |
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| Requirements | |
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| Substrate Fabrication and Metrology | |
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| Multilayer Films | |
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| At-Wavelength Metrology | |
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| Optics Lifetime | |
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| Contamination Processes | |
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| Impact of Contamination | |
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| Mitigation and Cleaning Techniques | |
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| Summary and Outlook | |
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| Acknowledgments | |
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| References | |
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| Multilayer Interference Coatings for EUVL | |
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| Overview and History of Multilayer Coatings in EUVL | |
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| Main Requirements for EUVL Coatings | |
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| Design of EUV Multilayer Coatings | |
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| Optical Constants and Material Selection | |
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| High-Reflective Mo/Si Mirrors | |
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| Broadband and Narrowband Mirrors | |
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| Multilayer Deposition Technologies | |
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| Imperfections in Mo/Si Multilayer Mirrors | |
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| Interface-Engineered Mo/Si Coatings | |
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| Mirrors with Enhanced Reflectance | |
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| Mirrors with Enhanced Thermal Stability | |
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| Stability of Mo/Si Coatings | |
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| Thermal Stability | |
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| Radiation Stability | |
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| Stress Reduction in Mo/Si Coatings | |
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| Concluding Remarks | |
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| Acknowledgments | |
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| References | |
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| EUV Metrology | |
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| Introduction | |
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| Optical Critical-Dimension (OCD) Techniques Using Scatterometry | |
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| Introduction, Limits of OCD | |
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| Scatterometry Measurement Modes | |
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| Test Structures and Models | |
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| Model Descriptions | |
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| Model Stability | |
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| Fundamental Limits | |
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| Sensitivity Analysis | |
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| EUV Mask Optical Inspection | |
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| OCD Using High-Resolution Microscopy | |
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| CD Metrology | |
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| Arrayed CD Targets | |
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| AFM for Water and EUV Mask Metrology | |
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| Reference Metrology Applications | |
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| AFM Data Output | |
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| Instrument Accuracy | |
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| New Directions in AFM Metrology in EUVL | |
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| Imaging Techniques for Overlay | |
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| In-Chip Overlay Targets | |
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| Superstructure Target Designs | |
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| Scatterometry for Overlay | |
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| Charged-Particle CD Metrology | |
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| Contamination-Free Operation | |
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| High-Precision Image and Data Acquisition | |
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| Accurate Model-Based Dimensional Metrology | |
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| Acknowledgments | |
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| References | |
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| EUV Photoresist | |
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| Introduction | |
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| Evolutionary Changes in Resist Technologies | |
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| History and Description of Chemically Amplified Resists | |
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| Chemically Amplified (CA) Resists | |
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| Acid Diffusion in CA Resists | |
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| DUV Resist Image Thermal Stability | |
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| 193-nm Resists | |
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| 193-nm Acrylic SLRs | |
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| Etch-Resistant Resists | |
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| EUV Resists | |
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| Special Requirements for EUV Resists | |
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| EUV Resists Exposure Performance | |
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| EUV Resist Materials and Polymers | |
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| EUV PAGs | |
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| Multilayer Resists and Pattern Transfer | |
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| Absorption Coefficients of EUV Resists | |
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| Line-Edge Roughness (LER) | |
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| Pattern Collapse | |
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| Outgassing | |
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| Summary | |
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| References | |
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| EUVL Masks | |
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| Introduction | |
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| Masks and Lithography | |
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| Overview of EUVL Masks | |
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| EUVL Mask Substrates | |
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| Coefficient of Thermal Expansion | |
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| Substrate Surface | |
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| EUVL Mask Blanks | |
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| Multilayer | |
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| Defect Inspection of Blank Masks | |
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| Defect Control of Blank Masks | |
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| EUVL Mask Absorber | |
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| Requirements of the EUVL Absorber Stack | |
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| Absorber Materials | |
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| EUVL Mask Pattern Generation | |
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| E-Beam Exposure | |
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| Resist Processing | |
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| EUVL Mask Etch | |
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| Plasma Etch Fundamentals | |
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| EUV Absorber-Layer Etching | |
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| Buffer-Layer Etching | |
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| Backend and Defect Control | |
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| Cleaning | |
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| Inspection | |
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| Repair | |
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| EUVL Mask Protection | |
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| Mask without Pellicle | |
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| Thermophoretic "Pellicle" Approaches | |
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| Conclusions | |
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| References | |
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| Index | |