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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 | |