Particles on Surfaces 1: Detection, Adhesion, and Removal

376 Pages·1989·10.84 MB·English

by  Stuart A. Hoenig (auth.)

Particles on
Surfaces 1
Detection, Adhesion, and Removal
Particles on
Surfaces 1
Detection, Adhesion, and Removal
Edited by
K. L. Mittal
IBM US Technical Education
Thornwood, New York
PLENUM PRESS • NEW YORK AND LONDON
Library of Congress Cataloging in Publication Data
Particles on surfaces I: detection, adhesion, and removal/edited by K. L. Mittal.
p. cm.
Proceedings of a symposium held in conjunction with the Seventeenth Annual
Meeting of the Fine Particle Society, held July 28-August 2, 1986, in San Francisco,
California.
Bibliography: p.
Includes index.
ISBN-13: 978-1-4615-9533-5 e-ISBN-13: 978-1-4615-9531-1
DOl: 10.1007/978-1-4615-9531-1
1. Particles-Congresses. 2. Surfaces (Technology)-Congresses. I. Mittal, K. L.
1945- . II. Fine Particle Society. Meeting (17th: 1986: San Francisco, Calif.)
TA418.78.P37 1988 88-28841
620'.43-dcI9 CIP
Proceedings of a symposium on Particles on Surfaces: Detection
Adhesion, and Removal, held in conjunction with the Seventeenth Annual
Meeting of the Fine Particle Society, held July 28-August 2, 1986,
in San Francisco, California
© 1988 Plenum Press, New York
Softcover reprint of the hardcover 1s t edition 1988
A Division of Plenum Publishing Corporation
233 Spring Street, New York, N.Y. 10013
All rights reserved
No part of this book may be reproduced, stored in a retrieval system, or transmitted
in any form or by any means, electronic, mechanical, photocopying, microfilming,
recording, or otherwise, without written permission from the Publisher
PREFACE
This volume chronicles the proceedings of the Symposium on Particles on
Surfaces: Detection, Adhesion and Removal held under the auspices of the
Fine Particle Society in San Francisco, July 28-August 2, 1986.
The study of particles on surfaces is extremely important in many areas
of human endeavor (ranging from microelectronics to optics to
biomedical). A complete catalog of modern precision and sophisticated
technologies where particles on surfaces are of cardinal importance will
be prohibitively long, but the following eclectic examples should
underscore the concern about particles on a variety of surfaces. In the
semiconductor world of shrinking dimensions, particles which, a few years
ago, were cosmetically undesirable but functionally innocuous can
potentially be killer defects now. As the device sizes get smaller, there
will be more and more concern about smaller and smaller particles. In the
information storage technology, the gap between the head and the disk is
very narrow, and if a particle is trapped in the gap that can have very
grave consequences. The implications of particulate contamination on
sensitive optical surfaces is all too manifest. So the particulate
contamination on surfaces is undesirable from functional, yield and
reliability points of view.
This symposium was organized with the following objectives in mind: to
bring together active practitioners in this field; to provide a forum for
discussion of the latest research and development activities in this
area; to provide opportunity for cross-pollination of ideas; and to
highlight topics which needed intensified effort. The response to this
Symposium was extremely gratifying and the general consensus was that a
comprehensive symposium on this topic was both timely and needed.
Concomitantly, the final technical program contained 51 papers covering
various ramifications of particles on surfaces. Apropos, the program
comprised both invited overviews and original research contributions. It
should be recorded that there were enlightening (not exothermic)
discussions both formally and informally throughout the duration of the
Symposium.
As for this proceedings volume, it contains a total of 28 papers divided
into four sections as follows: General Papers; Particle-Substrate
Interaction and Particle Adhesion; Particle Detection, Analysis and
Characterization; and Particle Removal. The topics covered include:
sources of particles and deposition of particles on surfaces; particle
substrate interaction and factors which influence such interaction;
particle adhesion measurement; various ways to detect, analyze and
characterize. particles on surfaces; various ways to remove particles from
a variety of surfaces; particle prevention and implications of
particulate contamination on surfaces. It should be recorded here
v
that all papers were peer reviewed and suitably modified before
acceptance and inclusion in this proceedings volume, as the peer review
is a desideratum to maintain the standard of publications.
May I add here that this is the Premier Volume on this topic and I
certainly hope it will be valuable to both the neophyte interested in
learning about particles on surfaces and to the veteran researcher who
wishes to know the latest developments. Apropos, this volume is
christened Volume 1 as the proceedings of the Second Symposium will be
labelled Volume 2. As a matter of fact, based on the interest and tempo
of activity in the world of particles on surfaces, we have decided to
hold symposia on this topic on a biennial basis.
Acknowledgements: First, it is my great pleasure to mention that this
Symposium was jointly organized by yours truly and Dr. M.B. (Arun) Ranade
and my sincere thanks are extended to him. Also my thanks go to the Fine
Particle Society for sponsoring this event. Next I am thankful to the
appropriate management of IBM Corporation, particularly A. Hermann, for
allowing me to organize this symposium and to edit this volume. Special
thanks are due to Lisa Honski of Plenum Publishing Corp. for her
continued interest in this project. The time and effort of the reviewers
is earnestly appreciated for making valuable comments. On a personal
note, my thanks are extended to my wife, Usha, for helping me in many
ways during the editing of this volume. Last, but not least, the co
operation, contribution and patience of the contributors is gratefully
acknowledged without which this book would not have seen the light of
day.
K.L. Mittal
IBM U.S. Technical Education
500 Columbus Ave.
Thornwood, NY 10594
CONTENTS
PART I. GENERAL PAPERS
Fine Particles on Semiconductor Surfaces: Sources, Removal and
Impact on the Semiconductor Industry
S.A. Hoenig..................................................... 3
Cleaning Semiconductor Surfaces: Facts and Foibles
A. Khi1nani..................................................... 17
Effect of Chemical Cleaning Sequencing on Particle
Addition/Reduction on Silicon Wafers
C.A. Peterson................................................... 37
Measuring Aerosol Particle Concentration in Clean Rooms and
Particle Areal Density on Silicon Wafer Surfaces
R.P. Donovan, B.R. Locke and D.S. Ensor.... .... ............ ..... 43
Particulate Contamination on Wafer Surfaces Resulting
From Hexamethy1disi1azane/Water Interactions
M.A. Logan, D.L. O'Meara, J.R. Monkowski and H. Cowles...... .... 57
Contamination of Chip Surfaces by Particles During Destructive
Physical Analysis of Integrated Circuit Devices
J.J. Weimer, J. Kokosinski, M.R. Cook and M. Grunze.... ......... 69
Calculation of Hamaker Coefficients for Metallic
Aerosols from Extensive Optical Data
I.W. Osborne-Lee................................................ 77
Soiling Mechanisms and Performance of Anti-Soiling
Surface Coatings
E. F. Cuddihy.................................................... 91
Implications of Particulate Contamination in the
Performance of Floppy Disks
A.F. Lewis and R.J. Rogers...................................... 113
PART II. PARTICLE-SUBSTRATE INTERACTION AND PARTICLE ADHES~ON
A Theoretical Review of Particle Adhesion
R.A. Bowling.................................................... 129
vii
The Electrostatic Force on a Dielectric Sphere Resting
on a Conducting Substrate
Wm. Y. Fowlkes and K. S. Robinson................................ 143
Electrostatic Charge Generation on Wafer Surfaces and
Its Effect on Particulate Deposition
M. Blitshteyn and A. Martinez............ ........................ 157
Toner Adhesion in Electrophotography
M.H. Lee and A.B. Jaffe......................................... 169
Adhesion and Removal of Particles: Effect of Medium
M.B. (Arun) Ranade, V.B. Menon, M.E. Mullins and V.L. Debler.... 179
Strong Adhesion of Dust Particles
R. Williams and R.W. Nosker..................................... 193
Prevention of Strong Adhesion of Dust Particles
R. W. Nosker and R. Williams..................................... 201
Dynamic Adhesion of Particles Impacting a Cylinder
H. -C. Wang and W. John.......................................... 211
Crossed Fiber Models of the Particle-Surface Interaction
W.S. Bickel and T.M. Wentze1.................................... 225
Sensitive New Method for the Determination of
Adhesion Force Between a Particle and a Substrate
G. L. Dybwad..................................................... 237
PART III. PARTICLE DETECTION, ANALYSIS AND CHARACTERIZATION
Detection of Particles on Clean Surfaces
J. Berger....................................................... 247
Detection of Particles Down to a "Few" Micrometers on Non-Specular
Microelectronic Substrates and Other Surfaces
C. Smith and T. Ross............................................ 253
Accurate Particle Counting for Bare Substrate Inspection
L. Galbraith, G. Kren, A. Neukermans and G. Pecen........ ....... 269
Automated SEM/EDS Image Analysis of Particles on Filter Blanks
G.J. Stone...................................................... 293
Particle Sizing and Counting with the Inspex EX20/20
C. Allemand..................................................... 307
PART IV. PARTICLE REMOVAL
Methods for Surface Particle Removal: A Comparative Study
J. Bardina...................................................... 329
Electrostatic Removal of Particles from Surfaces
D.W. Cooper, H.L. Wolfe and R.J. Miller......................... 339
Electric Field Detachment of Charged Particles
D.A. Hays....................................................... 351
VIii
A New Approach to the Removal of Sub-Micron Particles
From Solid (Silicon) Substrates
A. F .M. Leenaars................................................. 361
About the Contributors............................................. 373
Index. ... . ... ......... .. ........... .. .. .. .. ... ... ... .. . .. . ... ... . .. 381
ix
PART I. GENERAL PAPERS
FINE PARTICLES ON SEMICONDUCTOR SURFACES: SOURCES, REMOVAL AND
IMPACT ON THE SEMICONDUCTOR INDUSTRY
Stuart A. Hoenig
Department of Electrical and Computer Engineering
University of Arizona
Tucson, Arizona 85721
The impact of fine particles and organic contamination
on device yield is very serious. We have investigated several
technologies in this area. They include: 1) Application of
thermophoresis for the prevention of surface contamination.
2) The use of electrets for collection of particles that might
otherwise settle on surfaces. 3) The use of dry ice snow as a
cleaning medium for the removal of particulates and organic
contamination.
INTRODUCTION
Fine (less than 5 micrometers in diameter) particles are almost
everywhere in the atmosphere but, in general, they do not significantly
affect industrial processes. Semiconductor manufacturing operations
involve a very special environment where particles and organic vapors can
present serious problems in terms of loss of yield.
The general use of High Efficiency Particle Absolute (HEPA) filters
removes almost all of the particulates that come in with the "make up"
air. The resultant clean room particle spectrum is wholly dependent upon
the operation of the clean room and the personnel involved.
Exposure of collection plates in opera'tional clean rooms has
indicated that the major contaminant is lint from employee garments
followed by hair, cosmetics and clusters of skin cellsl ,2. All of these
entities are "employee related" and can be greatly reduced by proper
gowning and attention to "clean room rules." This has been accomplished
rather effectively in Japan, but many US facilities leave much to be
desired.
In this connection, it is interesting to note that hair, lint and
clusters of skin cells will "not" be observed by the usual laser airborne
particle counter and must be detected by optical microscopy or SEM
scanning of witness plates. The problem here is associated with size
(over 50 pm) or the long, slender, shape of the lint fragments. A study
of particles observed on witness plates in clean rooms is presented in
reference 3. A true measure of the contamination in a clean room will
3