Microelectronic Materials and Processes

The primary thrust of very large scale integration (VLS!) is the miniaturization of devices to increase packing density, achieve higher speed, and consume lower power. The fabrication of integrated circuits containing in excess of four million components per chip with design rules in the submicron range has now been made possible by the introduction of innovative circuit designs and the development of new microelectronic materials and processes. This book addresses the latter challenge by assessing the current status of the science and technology associated with the production of VLSI silicon circuits. It represents the cumulative effort of experts from academia and industry who have come together to blend their expertise into a tutorial overview and cohesive update of this rapidly expanding field. A balance of fundamental and applied contributions cover the basics of microelectronics materials and process engineering. Subjects in materials science include silicon, silicides, resists, dielectrics, and interconnect metallization. Subjects in process engineering include crystal growth, epitaxy, oxidation, thin film deposition, fine-line lithography, dry etching, ion implantation, and diffusion. Other related topics such as process simulation, defects phenomena, and diagnostic techniques are also included. This book is the result of a NATO-sponsored Advanced Study Institute (AS!) held in Castelvecchio Pascoli, Italy. Invited speakers at this institute provided manuscripts which were edited, updated, and integrated with other contributions solicited from non-participants to this AS!.

Inhalt

1 Silicon Crystal Growth.- 1.1 Introduction.- 1.2 Growth Characteristics.- 1.3 Impurity Incorporation.- 1.4 Trends in Large-Diameter Silicon Growth.- 1.5 Conclusions.- 2 Silicon Epitaxy.- 2.1 Introduction.- 2.2 EPI Equipment.- 2.3 Deposition.- 2.4 Doping.- 2.5 Autodoping.- 2.6 Pattern Shift.- 2.7 Defects.- 2.8 EPI Characterization.- 2.9 Conclusions.- 3 Silicon Oxidation.- 3.1 Introduction.- 3.2 Oxide Formation.- 3.3 Silicon Dioxide Properties.- 3.4 Conclusions.- 4 Physical Vapor Deposition.- 4.1 Introduction.- 4.2 Deposition Methods.- 4.3 Alloys and Compounds.- 4.4 Film Properties.- 4.5 Conclusions.- 5 Chemical Vapor Deposition.- 5.1 Introduction.- 5.2 Some Basic Aspects of CVD.- 5.3 Types of CVD Processes.- 5.4 Production CVD Reactor Systems.- 5.5 Deposition of Various Materials for VLSI Device Fabrication.- 5.6 Conclusions.- 6 Dielectric Materials.- 6.1 Introduction.- 6.2 Dielectric and Insulator Materials and their Applications in VLSI Technology.- 6.3 Methods of Film Formation and Equipment.- 6.4 Vertical Insulation in VLSI Technology.- 6.5 High Temperature Interconductor Insulation.- 6.6 Low Temperature Intermetal Insulation.- 6.7 Over-Metal Passivation Layer.- 6.8 Conclusions.- 7 Properties and Applications of Suicides.- 7.1 Introduction.- 7.2 Properties.- 7.3 Formation of Suicides and their Processing.- 7.4 Process Stability of Silicides-Resistivity, Stress and Device Reliability.- 7.5 Limitations.- 7.6 Conclusions.- 8 Forefront of Photolithographic Materials.- 8.1 Introduction.- 8.2 Extending Positive Resist Performance in the UV Region.- 8.3 Negative Resist Materials Which Do Not Swell During Development.- 8.4 Image Reversal Techniques.- 8.5 Contrast Enhancing Materials (CEMs).- 8.6 Amplification in Photoresist Technology.- 8.7 Deep UV Resists.- 8.8 Multilevel Resist Technology and Planarization.- 8.9 Bilayer Resist Processes.- 8.10 Gas-Phase-Functionalized Plasma-Developed Resists.- 8.11 Conclusions.- 9 Fine-Line Lithography.- 9.1 Introduction.- 9.2 Basic Fabrication Processes and Ultimate Resolution.- 9.3 UV Shadow Printing.- 9.4 X-Ray Lithography.- 9.5 Ion and Electron Beam Proximity Printing.- 9.6 Optical Projection.- 9.7 Scanning Electron Beam Lithography.- 9.8 Scanning Ion Beam Lithography.- 9.9 Conclusions.- 10 Dry Etching Processes.- 10.1 Introduction.- 10.2 RF Glow Discharges (Plasmas).- 10.3 Etching Considerations.- 10.4 Profile Control.- 10.5 Process Monitoring (Diagnostics).- 10.6 Other Dry Etch Techniques.- 10.7 Radiation Damage.- 10.8 Safety Considerations.- 10.9 Conclusions.- 11 Ion Implantation.- 11.1 Introduction.- 11.2 Ion Implanters.- 11.3 Range Distributions.- 11.4 Ion Damage.- 11.5 Annealing of Implanted Dopant Impurities.- 11.6 Ion Beam Annealing.- 11.7 Conclusions.- 12 Diffusion in Semiconductors.- 12.1 Introduction.- 12.2 Phenomenological Description.- 12.3 Point Defects and Atomistic Diffusion Mechanisms.- 12.4 Diffusion in Silicon.- 12.5 Diffusion in Germanium.- 12.6 Diffusion in Gallium Arsenide.- 12.7 Conclusions.- 13 Interconnect Materials.- 13.1 Introduction.- 13.2 Material and Process Requirements for VLSI Technology.- 13.3 Gate Metallization.- 13.4 Metal-Silicon Contacts.- 13.5 Interconnect Lines.- 13.6 Conclusions.- 14 Imperfection and Impurity Phenomena.- 14.1 Introduction.- 14.2 Imperfections and Impurities.- 14.3 Electrical Phenomena.- 14.4 Defect-Free Processing.- 14.5 Conclusions.- 15 Process Simulation.- 15.1 Introduction.- 15.2 Epitaxy.- 15.3 Ion Implantation.- 15.4 Diffusion.- 15.5 Lithography.- 15.6 Conclusions.- 16 Diagnostic Techniques.- 16.1 Introduction.- 16.2 Physical Background of Diagnostic Techniques.- 16.3 Analytical Aspects of Diagnostic Techniques.- 16.4 Areas of Application of Diagnostic Techniques.- 16.5 Specific Features and Applications of the Different Methods.- 16.6 Conclusions.- 16.7 Explanation of Acronyms and Abbreviations.