E-Beam Mask Writers

CONTENTS 4.1 Introduction 604.1.1 Role of E-Beam Writer in Lithography System 60 4.1.2 Mask Technology Roadmap 614.2 Development History of E-Beam Writer 62 4.2.1 The History of Evolution 62 4.2.2 An Example of the System 634.3 System Structures and Features 65 4.3.1 Stage Movement and Scanning Mode 654.3.1.1 Stage Movement 65 4.3.1.2 Scanning Mode 654.3.2 Acceleration Voltage 66 4.3.2.1 Coulomb Effect 66 4.3.2.2 Resist Sensitivity and Current Density 67 4.3.2.3 Proximity Effect 674.3.3 Probe Forming System and Beam Shapes 68 4.3.3.1 Point Beam System 68 4.3.3.2 Variable Shaped Beam and Cell Projection 694.3.4 Relationship Among Resolution, Accuracy, and Throughput 70 4.4 Technology for Throughput and Resolution 714.4.1 Electron Gun 71 4.4.2 Beam-Shaping Lens System 72 4.4.3 Objective Lens System 75 4.4.4 Multistage Deflection Architecture 76 4.4.5 Digital to Analog Converter 784.5 Technology for Image Placement Accuracy 79 4.5.1 Stage and Chamber Mechanics 804.5.1.1 Stage and Writing-Chamber Materials 80 4.5.1.2 Chamber Structure 80 4.5.1.3 Stage Structure 814.5.2 Temperature Balance 81 4.5.3 Mask Flatness 82 4.5.4 Superpose Writing 824.6 Technology for Critical Dimension Accuracy 83 4.6.1 Beam Shaping Function 844.6.1.1 Triangle Beam 84 4.6.1.2 Dual Shaping Deflector 854.6.2 Proximity Effect Correction 854.6.2.1 Dose Correction Method 86 4.6.2.2 Shape Modification Method 89 4.6.2.3 GHOST Method 89 4.6.2.4 Multilayer Resist Method 894.6.3 Multiple-Scattering Effects in Optical Column 90 4.6.3.1 Antireflection Plate 90 4.6.3.2 Fogging Effect Correction 914.7 Data Preparation 92 4.8 Commercially Available Systems 94 4.9 Summary 94 References 954.1.1 Role of E-Beam Writer in Lithography SystemElectron beam (e-beam) can easily be focused into nanometer diameter by electromagnetic or electrostatic lenses and can be steered by electromagnetic or electrostatic deflectors. So the e-beam can define patterns of a large-scale integrated circuit (LSI) with very high resolution in a resist. Tools that provide a focused e-beam have played an important role in the semiconductor industry for many years.