CLEANROOMS Facilities and Practices M. Kozicki Arizona State University with S. Hoenig University of Arizona and P. Robinson Motorola, Inc., SPS Inm5I Van Nostrand Reinhold ~ New York
NOTICE To the best of our knowledge, the information contained within this book is correct. However, the authors or publisher will not assume any responsibility or liability for the completeness or accuracy of, or consequences arising from, such information. Information regarding safety, such as knowledge relating to the hazard properties of materials or data such as Threshold Limit Values, can change on an annual basis, and therefore the reader should consult the appropriate publications from NIOSH, the ACGIH, and OSHA to obtain the most current information. Determination of the suitability and the manner of use of any information and/or product mentioned in this publication is the sole responsibility of the user. Mention of company or trade names or commercial products does not constitute endorsement or recommendation for use by the authors or publisher. Copyright 1991 by Van Nostrand Reinhold Softcover reprint ofthe hardcover 1 st edition 1991 Library of Congress Catalog Card Number 90-35627 ISBN-13: 978-94-011-7952-2 e-isbn-13: 978-94-011-7950-8 DOl: 10.1007/978-94-011-7950-8 All rights reserved. No part of this work covered by the copyright hereon may be reproduced or used in any form by an means-graphic, electronic, or mechanical, including photocopying, recording, taping, or information storage and retrieval systems - without written permission of the publisher. Van Nostrand Reinhold 115 Fifth Avenue New York, New York 10003 Chapman and Hall 2-6 Boundary Row London, SEI 8HN, England Thomas Nelson Australia 102 Dodds Street South Melbourne 3205 VictOria, Australia Nelson Canada 1120 Birchmount Road Scarborough, Ontario MIK 5G4, Canada 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 Library of Congress Cataloging in Publication Data Kozicki, M. N. (Michael N.), 1958- Cleanrooms, facilities and practices/by M.N. Kozicki, SA Hoenig, and P.J. Robinson. p.em. 1. Clean rooms. I. Hoenig, Stuart A. II. Robinson, P.J. (Patrick J.) Ill. Title. IV. Title: Clean rooms, facilities and practices. TH7694.K691990 696-de20 90-35627
Contents Preface ix 1. Introduction to Cleanroom Technology The Need for Cleanrooms The Contaminated World Manufacturing Yield and Product Reliability An Overview of Semiconductor Technology History Integration Yield and Reliability in Semiconductor Processing Other Cleanroom Applications The Impact of Cleanroom Technology 2. Microcontamination Types of Contamination Organic and Inorganic Substances Airborne Particulates Gases and Vapors Contamination in Liquids Sources of Contamination External Natural Sources External Industrial Sources Personnel Equipment and Facilities Production Materials and Processes Improper Work Practices Effects of Contamination Circuit Yield and Reliability 1 1 1 1 2 2 3 5 6 7 8 8 8 9 10 10 11 11 12 13 14 16 17 17 17 iii
iv Contents Mechanical Breakdown Biomedical and Pharmaceutical Problems Relating Product Health to Work Force Health 3. Controlled Environment Concepts Performance Considerations Clean room Parameters Ideal os. the Real World Performance Standards Particulate Standards Gas and Vapor Standards Parameter Measurement Microscopic Techniques Light-scattering Techniques Other Detection Methods Contamination Identification Monitoring Other Parameters 4. Creating Clean Areas Construction Materials and Techniques Basic Material Properties Wall Materials Floors Ceiling Systems Building Techniques Air Filtration Basic Air Filtration Theory Gas and Vapor Removal Other Contamination Reduction Techniques Practical Filtration Problems Airflow Turbulent Flow Laminar or Unidirectional Flow Pressurization Equipment and Material Decontamination Bringing Items into the Cleanroom Cleaning Techniques New Cleaning Technologies 21 22 23 24 25 25 25 26 27 27 30 32 32 33 35 37 40 46 48 49 49 49 50 54 55 57 58 58 61 62 64 66 66 67 70 70 71 72 76 79
Contents v 5. Cleanroom Layout Mixed Row Rooms Air Delivery Air Retum Local Unidirectional Row Fan Units Workstations SpotVLF Modular Cleanrooms Self-Contained Systems Retrofit Systems Tunnel Cleanrooms Tunnel Layout Service Chase Configurations Air Supply and Zoning Total Vertical Laminar Row Horizontal Laminar Flow Process EqUipment Equipment Integration Services Designing for Cleanroom Class Determining Class Requirements Lower-, Middle-, and Upper-class Rooms Cleanroom Models 6. Preconditioning, Control, and Static Air Handling Systems System Configurations Pre filtration Heating and Cooling Humidity Control Fans and Air Control Control Systems Controlled Parameters Types of Control Static Effects of Static Charge Sources and Detection of Charge Reduction by Ionizers Reduction by Other Means 80 80 80 82 83 83 85 85 89 89 89 90 90 92 95 97 100 101 101 103 104 104 106 107 110 111 111 113 115 115 116 118 120 120 121 124 124 125 126 127 128
vi Contents 7. Site and Structural Considerations Vibration Effects of Vibration External Sources Internal Sources Site Selection Structure Foundations Reducing Vibration Floor Isolation Plant Layout Internal Vibration Engineering Plant Isolation Sensitive Equipment Vibration Practices 8. Cleanrooms, Codes, and Legislation Principal Codes Building Codes Fire Codes Other Code Requirements Fire Protection Fire Systems Recirculation of Contaminants Smoke Removal Legislation 9. Ultrapure Water The Need for Ultrapure Water Constituents of Raw Water Sources of Water Inorganic Materials Organic Materials Micro-organisms Purification Techniques Water Purification Deionization Reverse Osmosis Filtration Measurement Techniques ROfOl System Configurations Typical System Configuration 130 130 130 132 134 135 136 136 136 137 139 140 140 140 141 141 142 142 143 145 148 148 148 152 155 157 161 162 162 163 163 164 167 167 169 169 170 172 174 175 177 177
ContentS vii Point of Use System Materials Operational Considerations Recirculation Changeovers Biocidal Treatments Operational Problems-Examples 10. Production Materials Gases Bulk Gas Storage and Distribution Cylinder Gas Use Monitoring and Cleaning Processes Gases Safety Aspects of Process Gas Systems Hazardous Gas Detection Wet Chemicals Bulk Chemical Storage and Distribution Bottled Chemical Use Monitoring and Cleaning Process Chemicals Spill Control Handling Other Materials Microcontamination Control for Solid Surfaces Safety Aspects of Other Materials 11. Personnel and Contamination Apparel Garment Materials Suit Styles Gloves and Skin Coatings Facemasks Particle Dispersion and Apparel Laundering Practices Garment Static Control Advanced Suit Concepts Use of Apparel Changing Room Layout Garment Storage and Monitoring Changing Procedures Shoe Cleaning and Air Showers Work Practices Personnel Motivation and Training General Microcontamination Practices 179 180 181 181 182 183 184 185 186 186 186 190 193 194 197 199 199 200 202 205 206 206 208 210 211 211 211 218 219 224 229 231 233 234 235 235 235 236 238 240 240 247
viii Contents Cleaning the Clean room and Cleanroom Wipers Worker Stress and Related Problems 248 249 250 12. Safety Issues 252 Properties of Hazardous Production Materials 253 Hazard Properties 253 Basic Toxicology 254 Effects of Common HPMs 257 Cleanroom Safety Practices 261 The Safety Team 261 Formulating Regulations 262 Safety Training 263 Exposure Monitoring 268 General Safety Practices 272 Equipment Layout for Safety 273 Maintenance Safety 276 Emergency Response 278 Safety Equipment 280 Protective Clothing 280 Personal Protection Systems 281 Handling Hazardous Production Materials 282 Safety Controls 282 Gas Safety Revisited 287 Wet Chemical Safety Revisited 289 Disposal 290 291 13. The Future of Controlled Environments 293 Advanced Cleanroom Concepts 294 Enclosed Transfer Systems 296 Robotics and Automation 304 In-situ Processing 306 Epilog---The Cleanroom as a System 307 Appendix 1 Federal Standard 209D 308 Appendix 2 Simplified Cleanroom Certification Procedure 356 Appendix 3 Program and Sample Output 361 Index 365
Preface In writing this book, our goal was to produce a much needed teaching and reference text with a fresh approach to c1eanroom technology. The most obvious technological reason for bringing this book into being is that c1eanrooms have become vital to the manufacture and development of hightechnology products in both the commercial and military sectors, and therefore people have to develop an understanding of them. Examples of c1eanroom applications include the manufacture of integrated circuits and other electronic components, precision mechanical assemblies, computer disks and drives, compact disks, optical components, medical implants and prostheses, pharmaceuticals and biochemicals, and so on. The book is written for anyone who is currently involved, or intends to become involved, with c1eanrooms. We intend it to be used by a wide range of professional groups including process engineers, production engineers, plant mechanical and electrical engineers, research engineers and scientists, managers, and so on. In addition, we believe it will be beneficial to those who design, build, service, and supply c1eanrooms, and may be used as a training aid for students who intend to pursue a career involving controlled environments and others such as c1eanroom operators and maintenance staff. We have attempted to steer clear of complex theory, which may be pursued in many other specialist texts, and keep the book as understandable and applicable as possible. The subject matter of the book is broad. A multiplicity of topics is necessary as c1eanrooms are extremely complex systems, and as such have a number of vital parts which make up the whole. We attempt to show the reader just exactly why c1eanrooms are necessary in a manufacturing or research sense and how the problems of microcontamination may be lessened by the construction and utilization of appropriate controlled environments and by the regulated behavior of the personnel who work in and around these environments. Apart from the discussions of the many technological areas, for example, filtration and ultrapure water production, there are also treatments of subjects such as work force safety and legal issues. This text is unique because it covers the apparently unconnected areas of contamination control and hazard management. However, we contend that these areas are actually often highly interdependent and that knowledge of these diverse fields is necessary ix
x Preface to enable one to operate in today's high technology industries in a fully effective manner. Clean rooms is principally about contamination; where it comes from, what it does in an industrial (or research) sense, and how we may construct facilities and utilize specialized practices to control it. Many of the concepts introduced are just good common sense; others have been the result of years of experience and research in the field. Above all, the book is intended to be practical, avoiding unnecessary theory and mathematics. Although we primarily use examples from the semiconductor industry, due to the direct experience of the authors in this technology sector, the information on facilities and practices is not specific to this area alone. This book is designed to promote a better understanding of the basics of cleanroom technology. By doing this we hope to amplify the impact of this technology in existing and future industries and in research programs. We would like to acknowledge the help of a number of people at Arizona State University, including Don Gerber for assistance with the cleanroom models, Ed Bawolek for the 2090 worksheet, and Chris Ricciuti and Nagesh Sreedhara for assistance with the manuscript. We would also like to say "thank you" to our long-suffering wives (particularly Rhona K., who got the worst of it) for putting up with the entire process.