Handbook of physical vapor deposition (PVD) processing : film formation, adhesion, surface preparation and contamination control

943 Pages·1998·7 MB·English

by  Donald M Mattox

HANDBOOK OF PHYSICAL
VAPOR DEPOSITION (PVD)
PROCESSING
Film Formation, Adhesion, Surface
Preparation and Contamination Control
by
Donald M. Mattox
Society of Vacuum Coaters
Albuquerque, New Mexico
NOYES PUBLICATIONS
np
Westwood, New Jersey, U.S.A.
Copyright © 1998 by Noyes Publications
No part of this book 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 permission in writing from the Publisher.
Library of Congress Catalog Card Number: 97-44664
ISBN: 0-8155-1422-0
Printed in the United States
Published in the United States of America by
Noyes Publications
369 Fairview Avenue, Westwood, New Jersey 07675
10 9 8 7 6 5 4 3 2 1
Library of Congress Cataloging-in-Publication Data
Mattox, D. M.
Handbook of physical vapor deposition (PVD) processing / by
Donald M. Mattox.
p. cm.
Includes bibliographical references and index.
ISBN 0-8155-1422-0
1. Vapor-plating--Handbooks, manuals, etc. I. Title.
TS695.M38 1998
671.7'35--dc21 97-44664
CIP
Dedication
To my wife
Vivienne
Without Vivienne’s constant support, encouragement, and
editorial assistance, this book would not exist. Her wide
spectrum of contacts within the vacuum equipment and
PVD technology industries has made the accumulation of
information in some sections of this book possible.
v
NOTICE
To the best of our knowledge the information in this publication is
accurate; however the Publisher does not assume any responsibil-
ity or liability for the accuracy or completeness of, or consequences
arising from, such information. This book is intended for informational
purposes only. Mention of trade names or commercial products does
not constitute endorsement or recommendation for use by the Publish-
er. Final determination of the suitability of any information or
product for use contemplated by any user, and the manner of that
use, is the sole responsibility of the user. We recommend that
anyone intending to rely on any recommendation of materials or
procedures mentioned in this publication should satisfy himself as
to such suitability, and that he can meet all applicable safety and
health standards.
Preface
The motivation for writing this book was that there was no single
source of information which covers all aspects of Physical Vapor Deposition
(PVD) processing in a comprehensive manner. The properties of thin films
deposited by PVD processes depend on a number of factors (see Sec. 1.2.2),
and each must be considered when developing a reproducible process and
obtaining a high product throughput and yield from the production line.
This book covers all aspects of PVD process technology from
characterizing and preparing the substrate material, through the deposition
process and film characterization, to post deposition processing. The
emphasis of the book is on the aspects of the process flow that are critical to
reproducible deposition of films that have the desired properties.
The book covers both neglected subjects, such as film adhesion,
substrate surface characterization, and the external processing environment,
and widely discussed subjects, such as vacuum technology, film properties
and the fundamentals of individual deposition processes. In this book, the
author relates these subjects to the practical issues that arise in PVD
processing, such as contamination control and substrate property effects on
film growth, which are often not discussed or even mentioned in the literature.
By bringing these subjects together in one book, the author has made it
possible for the reader to better understand the interrelationships between
various aspects of the processing and the resulting film properties. The
author draws upon his long experience in developing PVD processes,
teaching short courses on PVD processing, to not only present the basics but
vi
Preface vii
also to provide useful hints for avoiding problems and solving problems
when they arise. Some examples of actual problems and solutions (“war
stories”) are provided as foot notes throughout the text. The organization of
the text allows a reader who is already knowledgeable in the subject to scan
through a section and find subjects that are of particular interest. Extensive
references allow the reader to pursue subjects in greater detail if so desired.
An important aspect of the book is the useful reference material
presented in the Appendices. A glossary of over 2500 terms and acronyms
will be especially useful to those individuals that are just entering the field and
those who are not fully conversant with the English language. Many of the
terms are colloquialisms that are used in the field of Surface Engineering.
The author realizes that covering this subject is a formidable task,
particularly for one person, and that this effort is incomplete at best. He
would like to elicit comments, corrections, and additions, which may be
incorporated in a later edition of the book. In particular, he would like to elicit
“war stories” of actual problems and solutions. Credit will be given for those
which are used. Please contact the author at (ph.) 505-856-6810, (fax) 505-
856-6716, or e-mail [email protected].
Albuquerque, New Mexico Donald M. Mattox
August, 1997
Table of Contents ix
Table of Contents
1 Introduction ..........................................................................29
1.1 SURFACE ENGINEERING..........................................................29
1.1.1 Physical Vapor Deposition (PVD) Processes..................31
Vacuum Deposition....................................................32
Sputter Deposition......................................................33
Arc Vapor Deposition.................................................34
Ion Plating...................................................................34
1.1.2 Non-PVD Thin Film Atomistic Deposition Processes....35
Chemical Vapor Deposition (CVD) and PECVD ......35
Electroplating, Electroless Plating and Displacement
Plating......................................................................36
Chemical Reduction ...................................................37
1.1.3 Applications of Thin Films..............................................38
1.2 THIN FILM PROCESSING...........................................................39
1.2.1 Stages of Fabrication.......................................................39
1.2.2 Factors that Affect Film Properties.................................40
1.2.3 Scale-Up and Manufacturabilty ......................................43
1.3 PROCESS DOCUMENTATION...................................................44
1.3.1 Process Specifications.....................................................44
Laboratory/Engineering Notebook.............................46
1.3.2 Manufacturing Process Instructions (MPIs)....................46
1.3.3 Travelers..........................................................................47
1.3.4 Equipment and Calibration Logs.....................................48
1.3.5 Commercial/Military Standards and Specifications........48
1.4 SAFETY AND ENVIRONMENTAL CONCERNS......................50
ix
x Handbook of Physical Vapor Deposition (PVD) Processing
1.5 UNITS.............................................................................................50
1.5.1 Temperature Scales .........................................................51
1.5.2 Energy Units....................................................................51
1.5.3 Prefixes............................................................................51
1.5.4 Greek Alphabet ...............................................................52
1.6 SUMMARY....................................................................................52
FURTHER READING................................................................................53
REFERENCES............................................................................................54
2 Substrate (“Real”) Surfaces and Surface Modification....56
2.1 INTRODUCTION..........................................................................56
2.2 MATERIALS AND FABRICATION............................................57
2.2.1 Metals..............................................................................57
2.2.2 Ceramics and Glasses......................................................59
2.2.3 Polymers..........................................................................61
2.3 ATOMIC STRUCTURE AND ATOM-PARTICLE
INTERACTIONS........................................................................63
2.3.1 Atomic Structure and Nomenclature...............................63
2.3.2 Excitation and Atomic Transitions..................................64
2.3.3 Chemical Bonding...........................................................66
2.3.4 Probing and Detected Species.........................................67
2.4 CHARACTERIZATION OF SURFACES AND
NEAR-SURFACE REGIONS.....................................................69
2.4.1 Elemental (Chemical) Compositional Analysis..............71
Auger Electron Spectroscopy (AES)..........................72
Ion Scattering Spectroscopy (ISS and LEISS)...........73
Secondary Ion Mass Spectrometry (SIMS)................75
2.4.2 Phase Composition and Microstructure ..........................75
X-ray Diffraction........................................................75
Electron Diffraction (RHEED, TEM) ........................76
2.4.3 Molecular Composition and Chemical Bonding.............76
Infrared (IR) Spectroscopy.........................................76
X-ray Photoelectron Spectroscopy (XPS) or Electron
Spectroscopy for Chemical Analysis (ESCA)............79
2.4.4 Surface Morphology........................................................80
Contacting Surface Profilometry................................82
Scanning Tunneling Microscopy (STM) and Atomic
Force Microscopy (AFM).......................................83
Interferometry.............................................................84
Scanning Near-Field Optical Microscopy (SNOM) and
Photon Tunneling Microscopy (PTM)....................84
Scatterometry..............................................................85
Scanning Electron Microscope (SEM).......................85
Replication TEM ........................................................85
Adsorption—Gases and Liquids.................................86
Table of Contents xi
2.4.5 Mechanical and Thermal Properties of Surfaces.............87
2.4.6 Surface Energy................................................................88
2.4.7 Acidic and Basic Properties of Surfaces.........................90
2.5 BULK PROPERTIES.....................................................................91
2.5.1 Outgassing.......................................................................91
2.5.2 Outdiffusion....................................................................92
2.6 MODIFICATION OF SUBSTRATE SURFACES........................92
2.6.1 Surface Morphology........................................................92
Smoothing the Surface................................................92
Roughening Surfaces..................................................95
Vicinal (Stepped) Surfaces.......................................100
2.6.2 Surface Hardness...........................................................100
Hardening by Diffusion Processes ...........................100
Hardening by Mechanical Working.........................102
Hardening by Ion Implantation ................................102
2.6.3 Strengthening of Surfaces .............................................103
Thermal Stressing.....................................................103
Ion Implantation .......................................................104
Chemical Strengthening ...........................................104
2.6.4 Surface Composition.....................................................104
Inorganic Basecoats..................................................105
Oxidation..................................................................105
Surface Enrichment and Depletion...........................107
Phase Composition...................................................107
2.6.5 Surface “Activation”.....................................................108
Plasma Activation.....................................................108
Corona Activation.....................................................109
Flame Activation ......................................................110
Electronic Charge Sites and Dangling Bonds...........110
Surface Layer Removal............................................111
2.6.6 Surface “Sensitization”..................................................111
2.7 SUMMARY..................................................................................112
FURTHER READING..............................................................................112
REFERENCES..........................................................................................113
3 The Low-Pressure Gas and Vacuum Processing
Environment .......................................................................127
3.1 INTRODUCTION........................................................................127
3.2 GASES AND VAPORS...............................................................128
3.2.1 Gas Pressure and Partial Pressure.................................129
Pressure Measurement..............................................131
Identification of Gaseous Species.............................135
xii Handbook of Physical Vapor Deposition (PVD) Processing
3.2.2 Molecular Motion..........................................................136
Molecular Velocity...................................................136
Mean Free Path.........................................................136
Collision Frequency..................................................136
Energy Transfer from Collision
and “Thermalization”............................................137
3.2.3 Gas Flow........................................................................138
3.2.4 Ideal Gas Law................................................................140
3.2.5 Vapor Pressure and Condensation.................................141
3.3 GAS-SURFACE INTERACTIONS.............................................143
3.3.1 Residence Time .............................................................143
3.3.2 Chemical Interactions....................................................144
3.4 VACUUM ENVIRONMENT......................................................146
3.4.1 Origin of Gases and Vapors..........................................147
Residual Gases and Vapors......................................147
Desorption ................................................................148
Outgassing................................................................149
Outdiffusion..............................................................151
Permeation Through Materials.................................151
Vaporization of Materials.........................................152
Real and Virtual Leaks.............................................153
“Brought-in” Contamination....................................154
3.5 VACUUM PROCESSING SYSTEMS ........................................155
3.5.1 System Design Considerations and “Trade-Offs”.........157
3.5.2 Processing Chamber Configurations.............................157
Direct-Load System..................................................159
Load-Lock System....................................................159
In-Line System .........................................................161
Cluster Tool System .................................................162
Web Coater (Roll Coater).........................................162
Air-To-Air Strip Coater............................................163
3.5.3 Conductance..................................................................163
3.5.4 Pumping Speed and Mass Throughput .........................165
3.5.5 Fixturing and Tooling....................................................166
Substrate Handling ...................................................171
3.5.6 Feedthroughs and Accessories......................................171
3.5.7 Liners and Shields.........................................................171
3.5.8 Gas Manifolding............................................................172
Mass Flow Meters and Controllers...........................173
3.5.9 Fail-Safe Designs ..........................................................175
“What-If” Game .......................................................178
3.6 VACUUM PUMPING..................................................................179
3.6.1 Mechanical Pumps ........................................................179
Oil-Sealed Mechanical Pumps..................................180
Dry Pumps................................................................181
Diaphragm Pumps ....................................................182