The Foundations of Vacuum Coating Technology The Foundations of Vacuum Coating Technology Donald M. Mattox Management Plus, Inc. Albuquerque, New Mexico NOYES PUBLICATIONS WILLIAM ANDREW PUBLISHING Norwich, New York, U.S.A. i Copyright © 2003, Noyes Publications / William Andrew Publishing. All rights reserved. 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. Cover Art © 2003 by Brent Beckley / William Andrew Publishing Library of Congress Catalog Card Number: 2003004260 ISBN: 0-8155-1495-6 Published in the United States of America by Noyes / William Andrew Publishing 13 Eaton Avenue Norwich, NY 13815 1-800-932-7045 www.williamandrew.com www.knovel.com 10 9 8 7 6 5 4 3 2 1 This book may be purchased in quantity at discounts for education, business, or sales promotional use by contacting the Publisher. Plastics Design Library and its logo are trademarks of William Andrew Inc. Notice: To the best of our knowledge the information in this publication is accurate; however the Publisher does not assume any responsibility 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 Publisher. Final determination of the suitability of any information or product for any use, and the manner of that use, is the sole responsibility of the user. Anyone intending to rely upon any recommendation of materials or procedures mentioned in this publication should be independently satisfied as to such suitability, and must meet all appli- cable safety and health standards. Manufactured in the United States of America. Library of Congress Cataloging-in-Publication Data Mattox, D. M. The foundations of vacuum coating technology / Donald M. Mattox. p. cm. ISBN 0-8155-1495-6 (alk. paper) 1. Vacuum metallurgy--Congresses. 2. Metal coating--Congresses. I. Title. TN686.5.V3M38 2003 669'.028'4--dc21 2003004260 William Andrew Publishing, 13 Eaton Avenue, Norwich, NY 13815 Tel: 607/337/5000 Fax: 607/337/5090 The Foundations of Vacuum Coating Technology Dedication The author would like to dedicate this book to his wife, Vivienne, without whose support and encouragement this book would not have been written. He would also like to dedicate the book to his granddaughter, Lindsey, with the hope that when she grows up she will study the history of those subjects that are of interest to her. iii The Foundations of Vacuum Coating Technology Acknowledgments The author assumes responsibility for all errors of commission and omission and would like to encourage comments, corrections, and additions to be sent to [email protected]. The author would like to acknowl- edge Collin Alexander for providing material from the “proceedings” of the 1943 U.S. Army-sponsored confer- ence on “Application of Metallic Fluoride Reflection Reducing Films to Optical Elements”—the text of which may be found on the SVC Web Site at www.svc.org; Ric Shimshock for the reference to the early work on magnetron sputtering on webs; Bob Cormia for his comments on the early development of planar magnetrons; and Angus Macleod for input on the early work in optical coatings. Russ Hill made some important contributions, as did Bob Waits, who called my attention to Fred Wehner’s discussion on the etymology of the term “sputtering.” The author would like to express thanks to Phil Baumeister for calling attention to the very important RLG patent and thus to some interesting patent litigation. The author would particularly like to thank Julie Filatoff for her expert editing and formatting of this book, Linnea Dueker for her excellent job of scanning the illustrations, and Julie Romig for her critical reading of the manuscript. The SVC Oral History Project, located on the SVC Web Site at www.svc.org/H/H_OralInterviews.html, has also contributed some interesting details. Don Mattox would like to encourage anyone with historical papers, patents, pictures, or other materials related to the history of vacuum coating to contact him at [email protected]. v The Foundations of Vacuum Coating Technology Preface Vacuum coating processes consist of a source of vapor (atomic or molecular) of the material to be deposited, transport of the vapor to the surface to be coated, and condensation on the surface to form a thin film or coating with the desired properties. In the case of reactive deposition, availability of the reactive gas at the surface of the growing film and “activation” of the reactive gas are important. Generally all the necessary ingredients for different vacuum-coating processes were present long before the process was used in production. In some cases, such as Edison’s “Gold Moulded” cylinder phonograph record production (1902–1912), a vacuum coating process (“electrical evaporation,” “cathodic disintegration” or, as it was later called, “sputtering”) was the “enabling technology” that allowed mass production of the records. In other cases the use of vacuum coating processes has supplanted the use of other coating processes, such as electroplating, with a more environmentally friendly process. In still other cases the existence of vacuum coating processes allowed new applications and markets to be developed. An example is the deposition of “decorative- functional” coatings that have both a pleasing appearance (gold, brass, or gray-black for example) and wear resistance. As with many ideas, inventions, and inventors, it is often difficult to establish the originator of any particular idea or invention. The search is complicated by the information being in both the patent literature and the scien- tific/technical literature. Patents seldom cite relevant technical papers and technical papers seldom cite relevant patent literature. The field of vacuum coating is continually evolving and new processes, materials, and applications provide a fertile field for the historian. “Those that do not know the history of their field are doomed to repeat its mistakes or end up in patent litigation.” (G. Santayana, paraphrased) vii The Foundations of Vacuum Coating Technology Table of Contents Preface ............................................................................................................................................................... vii Introduction .......................................................................................................................................................... 1 Early Vacuum Science and Technology ............................................................................................................... 2 Early Electricity and Magnetism .......................................................................................................................... 5 Early Plasma Physics and Chemistry ................................................................................................................... 7 Some Scientific and Engineering Societies and Publications ............................................................................... 9 Patents and the U.S. Patent Office ..................................................................................................................... 10 Deposition Processes.......................................................................................................................................... 11 Sputter Deposition ....................................................................................................................................... 11 Thermal Evaporation ................................................................................................................................... 19 Arc Vapor Deposition .................................................................................................................................. 24 Chemical Vapor Deposition ......................................................................................................................... 27 Ion Plating ................................................................................................................................................... 30 Surface Preparation ........................................................................................................................................... 34 Summary ............................................................................................................................................................ 37 Endnotes ............................................................................................................................................................. 39 References .......................................................................................................................................................... 43 Acronyms Used in Vacuum Coating .................................................................................................................. 61 Glossary of Terms for Vacuum Coating............................................................................................................. 69 ix The Foundations of Vacuum Coating Technology Introduction Vacuum coatings processes use a vacuum (sub- are combined in the same chamber at the same time atmospheric pressure)