Microelectronic Materials and Processes

NATO ASI Series Advanced Science Institutes Series

A Series presenting the results of activities sponsored by the NA TO Science Committee, which aims at the dissemination of advanced scientific and technological knowledge, with a view to strengthening links between scientific communities.

The Series is published by an international board of publishers in conjunction with the NATO Scientific Affairs Division

A Life Sciences B Physics

C Mathematical and Physical Sciences

D Behavioural and Social Sciences E Applied Sciences

F Computer and Systems Sciences G Ecological Sciences H Cell Biology

Series E: Applied Sciences - Vol. 164

Plenum Publishing Corporation London and New York

Kluwer Academic Publishers Dordrecht, Boston and London

Springer-Verlag Berlin, Heidelberg, New York, London, Paris and Tokyo

Microelectronic Materials and Processes edited by

R.A. Levy AT & T Bell Laboratories, Murray Hill, New Jersey, U.8A

Kluwer Academic Publishers

Dordrecht / Boston / London

Published in cooperation with NATO Scientific Affairs Division

Proceedings of the NATO Advanced Study Institute on Microelectronic Materials and Processes II Ciocco, Castelvecchio Pascoli, Italy June 30 - July 11,1986

ISBN-13: 978-0-7923-0154-7 DOl: 10.1007/978-94-009-0917-5

e-ISBN-13: 978-94-009-0917-5

Published by Kluwer Academic Publishers, P.O. Box 17, 3300 AA Dordrecht, The Netherlands.

Kluwer Academic Publishers incorporates the publishing programmes of D. Reidel, Martinus Nijhoff, Dr W. Junk, and MTP Press.

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In all other countries, sold and distributed by Kluwer Academic Publishers Group, P.O. Box 322, 3300 AH Dordrecht, The Netherlands.

All Rights Reserved © 1989 by Kluwer Academic Publishers. Softcover reprint of the hardcover 1 st edition 1989 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner.

CONTENTS

List of Contributors xi

Preface xiii

Chapter 1 Silicon Crystal Growth w. Lin K. E. Benson

1.1 Introduction 1 1.2 Growth Characteristics 1 1.3 Impurity Incorporation 6 1.4 Trends in Large-Diameter Silicon Growth 18 1.5 Conclusions 23

Chapter 2 Silicon Epitaxy McD. Robinson

2.1 Introduction 25 2.2 EPI Equipment 27 2.3 Deposition 29 2.4 Doping 40 2.5 Autodoping 43 2.6 Pattern Shift 52 2.7 Defects 56 2.8 EPI Characterization 66 2.9 Conclusions 73

Chapter 3 Silicon Oxidation G. J. Declerck

3.1 Introduction 79 3.2 Oxide Formation 79 3.3 Silicon Dioxide Properties 109 3.4 Conclusions 127

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Chapter 4 Physical Vapor Deposition

W. D. Westwood

4.1 Introduction 133 4.2 Deposition Methods 136 4.3 Alloys and Compounds 164 4.4 Film Properties 182 4.5 Conclusions 195

Chapter 5 Chemical Vapor Deposition

W. Kern

5.1 Introduction 203 5.2 Some Basic Aspects of CVD 205 5.3 Types of CVD Processes 211 5.4 Production CVD Reactor Systems 218 5.5 Deposition of Various Materials for VLSI Device

Fabrication 224 5.6 Conclusions 240

Chapter 6 Dielectric Materials

W. Kern

6.1 Introduction 247 6.2 Dielectric and Insulator Materials and their

Applications in VLSI Technology 248 6.3 Methods of Film Formation and Equipment 252 6.4 Vertical Insulation in VLSI Technology 258 6.5 High Temperature Interconductor Insulation 258 6.6 Low Temperature Intermetal Insulation 263 6.7 Over-Metal Passivation Layer 269 6.8 Conclusions 270

Chapter 7 Properties and Applications of Silicides

s. P. Murarka

7.1 Introduction 275 7.2 Properties 279 7.3 Formation of Silicides and their Processing 293 7.4 Process Stability of Silicides-Resistivity,

Stress and Device Reliability 317 7.5 Limitations 318 7.6 Conclusions 319

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Chapter 8 Forefront of Photolithographic Materials G. N. Taylor

8.1 Introduction 325 8.2 Extending Positive Resist Performance in the UV Region 326 8.3 Negative Resist Materials Which Do Not Swell During

Development 335 8.4 Image Reversal Techniques 341 8.5 Contrast Enhancing Materials (CEMs) 347 8.6 Amplification in Photoresist Technology 353 8.7 Deep UV Resists 357 8.8 Multilevel Resist Technology and Planarization 368 8.9 Bilayer Resist Processes 372

8.10 Gas-Phase-Functionalized Plasma-Developed Resists 389 8.11 Conclusions 401

Chapter 9 Fine-Line Lithography

A. N. Broers

9.1 Introduction 409 9.2 Basic Fabrication Processes and Ultimate Resolution 410 9.3 UV Shadow Printing 413 9.4 X-Ray Lithography 414 9.5 Ion and Electron Beam Proximity Printing 419 9.6 Optical Projection 420 9.7 Scanning Electron Beam Lithography 427 9.8 Scanning Ion Beam Lithography 451 9.9 Conclusions 454

Chapter 10 Dry Etching Processes D. W. Hess

10.1 Introduction 459 10.2 RF Glow Discharges (Plasmas) 461 10.3 Etching Considerations 474 10.4 Profile Control 491 10.5 Process Monitoring (Diagnostics) 496 10.6 Other Dry Etch Techniques 510 10.7 Radiation Damage 511 10.8 Safety Considerations 513 10.9 Conclusions 513

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Chapter 11 Ion Implantation E. Rimini

11.1 Introduction 521 11.2 Ion Implanters 522 11.3 Range Distributions 529 11.4 Ion Damage 550 11.5 Annealing of Implanted Dopant Impurities 555 11.6 Ion Beam Annealing 571 11.7 Conclusions 576

Chapter 12 Diffusion in Semiconductors

U. Gosele

12.1 Introduction 583 12.2 Phenomenological Description 584 12.3 Point Defects and Atomistic Diffusion Mechanisms 590 12.4 Diffusion in Silicon 596 12.5 Diffusion in Germanium 622 12.6 Diffusion in Gallium Arsenide 623 12.7 Conclusions 629

Chapter 13 Interconnect Materials Y. Pauleau

13.1 Introduction 635 13.2 Material and Process Requirements for VLSI Technology 637 13.3 Gate Metallization 638 13.4 Metal-Silicon Contacts 650 13.5 Interconnect Lines 665 13.6 Conclusions 674

Chapter 14 Imperfection and Impurity Phenomena K. V. Ravi

14.1 Introduction 679 14.2 Imperfections and Impurities 680 14.3 Electrical Phenomena 717 14.4 Defect-Free Processing 735 14.5 Conclusions 767

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Chapter 15 Process Simulation

W. Fichtner

15.1 Introduction 775 15.2 Epitaxy 776 15.3 Ion Implantation 783 15.4 Diffusion 795 15.5 Lithography 810 15.6 Conclusions 839

Chapter 16 Diagnostic Techniques

H. W. Werner

16.1 Introduction 845 16.2 Physical Background of Diagnostic Techniques 852 16.3 Analytical Aspects of Diagnostic Techniques 862 16.4 Areas of Application of Diagnostic Techniques 871 16.5 Specific Features and Applications of the Different Methods 871 16.6 Conclusions 966 16.7 Explanation of Acronyms and Abbreviations 973

Index 981

LIST OF CONTRIBUTORS

K. E. BENSON

AT &T Bell Laboratories Allentown, Pennsylvania 18103

A. N. BROERS

Engineering Department Cambridge University Cambridge, England

G. J. DECLERCK

IMEC Leuven, Belgium

W. FICHTNER

Institute for Integrated Systems Swiss Federal Institute of Technology Zurich, Switzerland

.. U. GOSELE

School of Engineering Duke University Durham, North Carolina 27706

D. W. HESS

Department of Chemical Engineering University of California Berkeley, California 94720

xi

WERNER KERN

David Sarnoff Research Center RCA Laboratories Princeton, New Jersey 08543

W. LIN

AT & T Bell Laboratories Allentown, Pennsylvania 18103

s. P. MURARKA

Rensselaer Polytechnic Institute Center for Integrated Electronics Watervliet, New York 12189

Y PAULEAU

CNET 38243 Meylan, France

K. V. RAVI

Mobil Solar Energy Corporation Waltham, Massachusetts 02254

E. RIMINI

Dipartimento di Fisica Universita di Catania Catania, Italy

xii

McD. ROBINSON

ASM Epitaxy Tempe, Arizona 85282

G. N. TAYLOR

AT&T Bell Laboratories Murray Hill, New Jersey 07974

H. W. WERNER

Philips Research Laboratories Eindhoven, The Netherlands

W. D. WESTWOOD

Bell Northern Research Ottawa, Canada

PREFACE

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!. A 28 hour video program providing an audiovisual documentation of the contents of this book has also been produced. Information about this program is available from the editor.

In the course of editing this book, many people have assisted and offered their support. First, I wish to thank the authors for their enlightening contributions and patience during the lengthy editing process. I also wish to thank the reviewers, N. Erdos, D. C. Jacobson, M. D. Giles, and D. E. Ibbotson for their valuable comments. Thanks are due to M. A. Cappuzzo, E. D. Miller, P. Carracino and R. A. Matula for the diverse activities involved in researching and laying out material for this volume. I am indebted to the Text Processing group in Murray Hill and specifically G. Moore for preparation of the many

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xiv Preface

iterations required to produce the final manuscript. I specially wish to thank Dr. C. Sinclair at NATO as well as Dr. E. Van Landingham and Dr. D. Flood at NASA without whose generous financial support this ASI and the events leading to this publication would not have been realized. Last, but not least, I wish to express my appreciation to the management of AT&T Bell Laboratories for providing the opportunity of working on this book.

Murray Hill, New Jersey R. A. Levy