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ISBN 978-1-315-89680-9
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www.crcpress.com
Polymers
for
Electronic
Applications
Editor
Juey H. Lai, Ph.D.
Lai Laboratories, Inc.
Burnsville, Minnesota
Boca Raton London New York
CRC Press, Inc.
CRC Press is an imprint of the
Boca Raton, Florida
Taylor & Francis Group, an informa business
First published 1989 by CRC Press
Taylor & Francis Group
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Boca Raton, FL 33487-2742
Reissued 2018 by CRC Press
© 1989 by CRC Press, Inc.
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Library of Congress Cataloging-in-Publication Data
Polymers for electronic applications, editor, Juey H. Lai
p. cm.
Includes bibliographies and index.
ISBN 0-8493-4704-1
1. Electronics—Materials. 2. Polymers.
I. Lai, J. H. (Juey H.)
TK7871.15.P6P6261989 621‘ .381—dc20 89-9860
A Library of Congress record exists under LC control number: 89009860
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PREFACE
Polymers have been increasingly used in many areas of electronics in recent years. This is in
part due to the versatility of synthetic methods which can modify polymer properties to fit the
need, and in part due to the feasibility of processing and fabrication of polymers into a particular
desired form, e.g., a large area thin film with controlled thickness. The objective of this book is
to review and discuss some important applications of polymers in electronics. The first three
chapters discuss the current primary applications of polymers in semiconductor device manu-
facturing: polymers as resist materials for integrated circuit fabrication, polyimides as electron-
ics packaging materials, and polymers as integrated circuit encapsulants.
The emergence of conducting polymers as a new class of electronic materials will have a
profound effect on future electronic products. Considerable research is currently underway in
the field of conducting polymers. Chapters 4 and 5 discuss recent research in electrically
conducting polymers and ionically conducting polymer electrolytes, respectively. Chapter 6
describes an emerging area which could be important for future electronics and electro-optics:
Langmuir-Blodgett technique for deposition of extremely thin film of controlled film thickness.
The field of polymers for electronic applications has grown very large indeed, and it is not
feasible to cover all areas in a single volume. The book covers six important areas which are of
current interest. Attempts have been made by the authors to cite many references which should
be useful to readers for further reading.
THE EDITOR
Juey H. Lai, Ph.D., is President, Lai Laboratories, Inc., Burnsville, MN. Priorto founding Lai
Laboratories in 1987, he was a Staff Scientist at Physical Sciences Center, Honeywell, Inc.,
Bloomington, MN.
Dr. Lai received his B.S. degree in chemical engineering from National Taiwan University,
Taipei, Taiwan, and his M.S. in chemical engineering and Ph.D. in physical chemistry from the
University of Washington, Seattle. After completing postdoctoral research at the University of
Minnesota, Minneapolis, he joined Honeywell as Principal Research Scientist in 1973. He was
appointed Senior Principal Research Scientist in 1978 and Staff Scientist in 1983.
Dr. Lai is a member of the American Chemical Society, a fellow of the American Institute of
Chemists and a member of the honor societies Sigma Xi and Phi Lambda Upsilon.
He received Honeywell's highest technical award, the H. W. Sweatt Award, in 1981. He has
seven patents and was designated as a Star Inventor by Honeywell. He was the Principal
Investigator of several contracts funded by the U.S. Army Electronics Technology and Devices
Laboratory and has published over 40 papers in polymer resists, advanced microlithography,
polyimides, polymer gas sensor, and polymer liquid crystals. His current interests are in the
development of advanced polymeric materials for microelectronics and biomedical applica-
tions.
CONTRIBUTORS
Ronald J. Jensen, Ph.D. James S. Tonge, Ph.D.
Senior Principal Research Scientist Project Chemist
Sensors and Signal Processing Laboratory Dow Coming
Honeywell, Inc. Midland, Michigan
Bloomington, Minnesota
Juey H. Lai, Ph.D.
President
Stephen T. Wellinghoff, Ph.D.
Lai Laboratories, Inc.
Staff Scientist
Burnsville, Minnesota
Department of Chemistry and Chemical
Engineering
Scott E. Rickert, Ph.D.
Southwest Research Institute
President
San Antonio, Texas
NanoFilm Corporation
Strongsville, Ohio
Duward F. Shriver, Ph.D.
Professor Ching-Ping Wong, Ph.D.
Department of Chemistry Distinguished Technical Staff
Northwestern University AT&T Bell Laboratories
Evanston, Illinois Princeton, New Jersey
The editor and authors wish to thank the following persons for their comments and suggestions
in reviewing the manuscripts: Mr. Robert Ulmer of Honeywell, Inc. and Dr. Lloyd Shepherd of
Cray Research for reading Chapter l; Mr. David Pitkanene of Honeywell for reading Chapter
3; Dr. Robert Lyle of Southwest Research Institute and Professor Gary Wnek of Rensselaer
Polytechnic Institute for reviewing Chapter4; Professor Austin Angell of Purdue University and
Professor B. B. Owens and his colleagues at the University of Minnesota for reviewing Chapter
5; and Professor Jerome Lando of Case Western Reserve University for reviewing Chapter 6.
Nora Madson deserves special thanks for her excellent work in typing the manuscripts. I wish
to thank my wife, Li, for her support and assistance during the preparation of the volume.
Juey H. Lai
Burnsville, MN
February 1989
TABLE OF CONTENTS
Chapter 1
Polymer Resists for Integrated Circuit (I C) Fabrication .......................................................... 1
Juey H. Lai
Chapter 2
Polyimides: Chemistry, Processing, and Application for Microelectronics .......................... 33
R. J. Jensen and Juey H. Lai
Chapter 3
Integrated Circuit Device Encapsulants ................................................................................. 63
Ching-Ping Wong
Chapter4
Electrically Conducting Polymers for Applications .............................................................. 93
S. T. Wellinghoff
Chapter 5
Polymer Electrolytes ............................................................................................................ 157
James S. Tonge and D. F. Shriver
Chapter 6
Langmuir-Blodgett Films: Langmuir Films Prepared by the Blodgett Technique .............. 211
Scott E. Rickert
Index .................................................................................................................................... 227
1
Chapter I
POLYMER RESISTS FOR INTEGRATED CIRCUIT (IC) FABRICATION
Joey H. Lai
TABLE OF CONTENTS
I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
II. Fundamental Properties of Polymer Resists ....................................... 2
A. Application of Polymer Resists for IC Fabrication ........................ 2
B. Brief Introduction to Micro lithography .................................... 3
I. Photolithography ................................................... 3
2. Electron-Beam Lithography ........................................ 5
3. X-Ray Lithography ................................................ 8
C. General Requirements of Polymer Resists; Factors Which
Affect the Resist Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
I. Sensitivity ......................................................... 9
2. Resolution ........................................................ II
3. Thermal Stability ................................................. II
4. Adhesion .......................................................... 12
5. Dry and Wet Etch Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
III. Chemistry of Polymer Resists .................................................... 14
A. Photoresists ............................................................... 14
B. Electron Resists .......................................................... 15
I. Positive Resists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2. Negative Resists .................................................. 18
C. Deep-UV Resists ......................................................... 20
D. X-Ray Resists ............................................................ 21
E. Dry Developable Resists ................................................. 22
F. Multilayer Resists ........................................................ 24
IV. Recent Developments and Future Outlook ....................................... 26
A. Recent Developments .................................................... 26
I. Nons welling Negative Photoresists ................................ 26
2. Organosilicon Polymer Resists .................................... 27
B. Future Outlook ........................................................... 28
References ............................................................................... 28
