Polymers for Electronic & Photonic Application

658 Pages·1993·11.061 MB·English

by  C. P. Wong (Eds.)

Polymers for Electronic and
Photonic Applications
Edited by
C. P. Wong
A T& Τ Bell Laboratones
Pnnceton, New Jersey
ACADEMIC PRESS, INC.
Harcourt Brace Jovanovich, Publishers
Boston San Diego New York
London Sydney Tokyo Toronto
This book is printed on acid-free paper. @
Copyright © 1993 AT&T Bell Laboratories
All rights reserved.
No part of this publication may be reproduced or
transmitted in any form or by any means, electronic
or mechanical, including photocopy, recording, or
any information storage and retrieval system, without
permission in writing from the publisher.
ACADEMIC PRESS, INC.
1250 Sixth Avenue, San Diego, CA 92101-4311
United Kingdom Edition published by
ACADEMIC PRESS LIMITED
24-28 Oval Road, London NW1 7DX
Library of Congress Cataloging-in-Publication Data:
Polymers for electronic and photonic applications/edited by C. P. Wong,
p. cm.
Includes bibliographical references and index.
ISBN 0-12-762540-2
1. Electronics—Materials. 2. Photonics—Materials. 3. Polymers.
I. Wong, C. P., date.
TK7871.15.P6P6 1993 92-10971
621.381—dc20 CIP
Printed in the United States of America
92 93 94 95 96 EB 9 8 7 6 5 4 3 2 1
Contributors
Numbers in parentheses indicate the pages on which the authors' contributions begin.
RONALD s. BAUER, Shell Development Company, Westhollow Research
Center, P.O. Box 1380, Houston, TX 77251-1380 (287)
GARY τ. BOYD, Photonics Research Laboratory, 3M Corporate Research
Laboratory, St. Paul, MN 55144 (467)
BRUCE L. BOOTH, Central Research and Development, Ε. I. du Pont de
Nemours & Co. (Inc.), Wilmington, Delaware 19880-0357 (549)
G. THOMAS DAVIS, Materials Science and Engineering Laboratory, National
Institute of Standards and Technology, Gaithersburg, MD 20899 (435)
ROLF E. FUNER, AMP-AKZO Corporation, 710 Dawson Drive, Newark, DE
19713 (333)
DAVID B. JAMES, AMP-AKZO Corporation, 710 Dawson Drive, Newark,
DE 19713 (333)
MARK G. KUZYK, Washington State University, Department of Physics,
Pullman, WA 99164-2814 (507)
CHUNG J. LEE, Microelectronic and Computer Technology Corporation,
12100 Technology Boulevard, Austin, Texas 78727 (249)
DAISUKE MAKINO, Hitachi Chemical Co., Ltd., Yamazaki Works, 13-1,
4-chome, Higashi-cho, Hitachi-shi, Ibaraki 317 Japan (221)
DAVID J. MONK, Department of Chemical Engineering, University of Cali-
fornia at Berkeley, Berkeley, California 94720 (120)
JOSE A. ORS, AT&T Bell Laboratories, P.O. Box 900, Princeton, NJ 08540
(387)
E. REICHMANIS, AT&T Bell Laboratories, Murray Hill, New Jersey 07974
(67)
COURTLAND N. ROBINSON, AT&T Bell Laboratories, Room 2F-25, 1600
Osgood Street, North Andover, Massachusetts 01845 (633)
xi
xii CONTRIBUTORS
MICHAEL R. RUBNER, Department of Materials Science and Engineering,
Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
(601)
HIDETAKA SATOU, Hitachi Chemical Co., Ltd., Yamazaki Works 13-1,
4-chome, Higashi-cho, Hitachi-shi, Ibaraki 317 Japan (221)
JANE M. SHAW, IBM T. J. Watson Research Center, P.O. Box 218, York-
town Heights, New York 10598 (1)
DAVID s. SOANE, Department of Chemical Engineering, University of
California at Berkeley, Berkeley, California 94720 (120)
F. R. WIGHT, AT&T Bell Laboratories, 4500 Laburnum Avenue, Richmond,
Virginia 23231 (387)
c. p. WONG, AT&T Bell Laboratories, P.O. Box 900, Princeton, New Jersey
08540 (167)
Preface
The invention of the transistor by Bardeen, Brittain, and Schockley at
AT&T Bell Laboratories in 1948 began the modern electronic evolution.
However, the development of integrated circuitry by Noyce of Fairchild
Semiconductor and Kilby of Texas Instruments in 1959 revolutionized the
electronic industry, both in terms of the technological and the economic
growth. Today, we have seen the complexity of the semiconductor technol-
ogy experience an exponential increase in the number of components per
chip (over 64 Μ bit/chip) and an exponential decrease in feature size to
submicron line width and spacing. Polymers have played a critical role in
advancing this technology. The miniaturization and advances of semicon-
ductor VLSI devices are due to the advances of such polymers as deep
UV, x-ray, electron beam lithographic submicron resists, interlayer di-
electrics, passivating thin film, electronic packaging and interconnects.
Furthermore, the advances in processing and fabrication techniques of
these polymers into some unique structures, such as ultra-thin L-B film,
have made the recent advances in semiconductor possible. Photonic tech-
nology with its enormous potential as non-linear optics and optical wave-
guide will have immense potential application in communications (optical
switches and optical transmission), data storage and retrievals.
The objective of this book is to review and discuss some important
applications of polymers in electronic and photonic applications. Each of
the authors are experts in their field and we have made special efforts to
include the latest references which are useful to the reader. This book has
been organized into 15 chapters, each representing a specific field of
interest. Chapter 1 discusses an overview of polymers for electronic and
photonic applications. Chapter 2 describes the latest development in
chemistry of polymers for microlithographic applications. Chapter 3 dis-
cusses the interconnect dielectric materials and processes. Chapter 4 deals
xiii
xiv PREFACE
with the recent advances in materials and processes of IC encapsulant,
particularly focusing on silicone as hermetic equivalent electronic packag-
ing. Chapter 5 discusses the recent developments and applications of
polyimides. Chapter 6 describes details in silicone-polyimides technologies.
Chapter 7 discusses detailed application of epoxy in electronics. Chapter 8
is dedicated to the recent advances in high performance engineering
thermoplastics for electronic applications. Chapter 9 focuses on photopoly-
mers for high density circuitry interconnections. Chapter 10 reviews the
recent advances of piezoelectric polymers. Chapters 11, 12, and 13 discuss
the latest development of polymers for non-linear optics, third order
susceptibilities and integrated optical waveguides respectively, an emerging
technology for polymers in photonic applications. Chapter 14 reviews the
Langmuir-Blodgett manipulation of electrically and optically responsive
polymers. And finally, Chapter 15 discusses the importance aspect of
mechanical properties of polymers in electronic applications.
To achieve the high level of accuracy of this text, each chapter was read
by three reviewers. I am indebted to all the authors who serve as careful
reviewers to their colleagues' chapters. In addition to the authors, I would
like to thank M. Bowden, E. Chandross, A. Husain, J. LeGrange,
A. Lovinger, R. Lytel, S. MacDonald, J. Markham, C. May, D. Powell,
J. Segelken, K. Singer, J. Sohn, C. Sullivan, K. Takahashi, and S. Tripathy
for their diligent comments and time in the reviewing process.
The field of polymers for electronic and photonic applications is quite
broad, and it is impossible to cover every aspect of them. We have
attempted to include most major areas with their latest references which
should be useful to our readers who work in this vast growing discipline.
With the advances of IC technology, there is always a constant need of
improved polymers for electronic and photonic applications. This is a
challenge that demands the continuous and active collaborative efforts
between chemists, physicists, material scientists, device and package design
engineers.
C. P. Wong
POLYMERS FOR ELECTRONIC AND PHOTONIC APPLICATIONS
Overview of Polymers for Electronic
and Photonic Applications
JANE M. SHAW
IBM T. J. Watson Research Center
Yorktown Heights, New York
I. Introduction . .1
II. Radiation-Sensitive Resists . .5
A. Polymers for Optical Lithography .11
B. Polymers for Electron Beam Lithography .30
C. Polymers for X-Ray Lithography .37
D. Polymers for Ion Beam Lithography .39
III. Polymers for Packaging Applications .41
A. Printed Circuit Boards .41
B. Single-Chip Packaging .42
C. Multichip Packaging · .46
IV. Active Polymers .53
A. Conducting Polymers .53
B. Polymers for Optical Interconnects .56
C. Molecular Electronics .57
V. Conclusions .58
References .59
I. Introduction
This century, we have witnessed the birth of the "information age", an
electronics revolution that has changed and expanded our world. This
revolution began in 1948 with the invention of the bipolar transistor by
Shockley, Bardeen, and Brittain [1] at AT&T Bell Laboratories. By the
early 1960s, a short 12 years later, Texas Instruments [2] and Fairchild
commercialized the first integrated circuits, using silicon and planar fabri-
cation techniques, and the semiconductor industry was born. Since then, as
seen in Fig. 1, the number of logic circuits and bits per chip has doubled
every year from 1970 to the present.
ι
Copyright © 1993 AT&T Bell Laboratories
All rights of reproduction in any form reserved.
ISBN 0-12-762540-2
2 JANE Μ. SHAW
P
P CHI
HI
C R
R PE
PE S
S UIT
BIT RC
M CI
A C
DR GI
O
L
YEAR
FIG. 1. Circuit density as a function of year of introduction (after Tummala and
Rymaszewski, Ref. 8, 1989).
A device, or single transistor element, is simply a junction between two
types of semiconductor materials (p and n) formed by diffusing dopants
into the silicon substrate. When many thousands of these devices are
interconnected, using metal wiring such as aluminum, a VLSI circuit (very
large scale integrated circuit) is formed. Figure 2 is a schematic of an
Resistor Transistor Diode Capacitor
.Oxide Aluminum
ρ - type substrate
FIG. 2. Schematic of the devices in an integrated circuit.
POLYMERS FOR ELECTRONIC AND PHOTONIC APPLICATIONS 3
integrated circuit. The devices themselves, consisting of resistors, transis-
tors, diodes, and capacitors, are formed in the body of the silicon wafer
called the masterslice. These devices are then connected with metal wiring
and insulated in a multilevel structure to form the completed circuits
[3-7]. These chips, approximately \ in square, are then tested, excised
from the wafer, and "packaged."
The package serves several functions. It enables the chip to communi-
cate to the outside world by supplying power and signal paths, and it also
provides mechanical support, protection, and cooling for the chip. The
methods of packaging are legion, and the packaging approach depends on
the performance criteria of the chip and the total system design [8, 9].
Figure 3 is a schematic of a high-performance package where many chips
are mounted to a multilevel ceramic carrier that is then plugged into a
board. The ever-increasing density of chip circuitry is placing a great
demand on the wiring necessary for high-speed "chip-to-chip" communica-
tions, and also for high-speed "package-to-package" signal and power
communication. Polymer materials can be used on the top of the ceramic
or silicon carrier to achieve this necessary increase in performance. The
screened metal paste technology used in ceramic carriers limits the metal
Chip
Polyimide Thin-Film
Signal Layers with
Ground Planes
\
Top Surface
Metalization
Ground
Signal
Signal
Ground
EZZZ3 νζζζζζλ
Ezzza
> Power & Ground
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mm
Υ/////////Λ TZZZZZZ. J
Ceramic Base Substrate
with Power & Ground
I/O Pin Planes
FIG. 3. Schematic of the NEC multichip high-performance package (after Watari and
Murano, Ref. 13, ©1984 IEEE).
4 JANE Μ. SHAW
line width to 25 μτη. However, because polymer films can be defined using
current chip lithographic technology, the wiring density can be increased.
The circuit speed will also be increased as the metal lines are embedded in
a polymer, which has a significantly lower dielectric constant than a
ceramic material. Many companies either are using this thin film wiring in
a product, or have the technology in development [10-14].
This tremendous growth in density and performance of both the chip
and the package depends on a synergistic relationship between advanced
circuit and system designs, and the materials, tools, and processes used to
bring these designs to fruition. From the early 1950s, polymers have been a
key element in the growth of the semiconductor industry. The progression
of polymers from "art" to science has led to new synthetic procedures and
a basic understanding of the relationship between molecular structure and
the mechanical, physical, and thermal properties of polymers. As the
ability to engineer the properties of polymers has grown, the polymer
industry has been able to supply an ever-increasing variety of materials to
meet the needs for lightweight, easily handled, low-cost polymer materials
to fabricate and package logic and memory chips. These materials range
from radiation-sensitive resists used to pattern the circuitry on chips and
boards, to the polymers used both as insulators on chip carriers them-
selves, and the encapsulants for mechanical and corrosion protection of
these chips. As can be seen in Fig. 4, the major uses of polymer materials
today are the following:
• Radiation-sensitive stencils to define devices and interconnect wiring
on the chip and package
• Dielectric materials for use as chip carriers and as insulators to
reduce shorts between multilevel metal interconnects
• Encapsulation materials for corrosion and mechanical protection
The need for these materials has created over a billion-dollar industry
worldwide, and this figure excludes the common engineering plastics that
are used for keyboards, cables, and computer cases. Most polymers used
for semiconductor and packaging applications may be considered as "pas-
sive," i.e., they do not take an active part in the functioning of the device.
However, new "active" materials are emerging. These include specifically
designed polymeric systems such as the following:
• Conducting polymers to conduct current for electronic applications
• Nonlinear optical materials to transmit or switch light for photonic
applications