Manufacturing Technology in the Electronics Industry Manufacturing Technology in the Electronics Industry An introduction Phillip R. Edwards Principal Scientific Officer, British Raii Research, Derby, UK. luni SPRINGER-SCIENCE+BUSINESS MEDIA, B.V. First edition 1991 © 1991 Phillip R. Edwards Originally published by Chapman & Hali 1991 Softcover reprint of the hardcover 1s t edition 1991 Typeset in 1O/12pt Palatino by Columns Design & Production Services Ud. ISBN 978-0-412-37130-1 Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the UK Copyright Designs and Patents Act, 1988, this publication may not be reproduced, stored, or transmitted, in any form or by any means, without the prior permission in writing of the publishers, or in the case of reprographic reproduction only in accordance with the terms of the licences issued by the Copyright Licensing Agency in the UK, or in accordance with the terms of licences issued by the appropriate Reproduction Rights Organization outside the UK. Enquiries concerning reproduction outside the terms stated here should be sent to the publishers at the UK address printed on this page. The publisher makes no representation, express or implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made. A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data Edwards, Phillip R., 1958- Manufacturing technology in the electronics industry : an introduction / Phillip R. Edwards. p. cm. Includes bibliographical references and index. ISBN 978-0-412-37130-1 ISBN 978-94-011-3130-8 (eBook) DOI 10.1007/978-94-011-3130-8 1. Electronic apparatus and appliances---Design and construction. 2. Electronic industries. 3. Printed circuits---Design and construction. 1. Title. TK7836.E39 1991 621.381-dc20 91-2819 CIP @ Printed on permanent acid-free text paper, manufactured in accordance with the proposed ANSIINISO Z 39.48-199X and ANSI Z 39.48-1984 Contents Contents Preface vii 1 Introduction to the electronics industry 1 1.1 A history of the electronics industry 2 1.2 The electronics market 10 1.3 Electronics manufacturing company structure 13 1.4 Test engineering and quality assurance 18 2 Electronic components 26 2.1 Component interconnection methods 26 2.2 Electronic components 27 2.3 Component packaging 48 2.4 Cabling 61 2.5 Component quality assurance 62 3 Electronic design 64 3.1 Quality and reliability assessment 64 3.2 The product design process 69 3.3 Circuit design 73 3.4 Integrated circuit design 77 3.5 Circuit layout 81 4 Semiconductor device manufacture 91 4.1 Semiconductor materials 92 4.2 Clean room requirements 94 4.3 Silicon wafer manufacture 97 4.4 Photolithography 99 4.5 Layer fabrication processes 102 4.6 Bipolar junction transistor fabrication 110 4.7 Field effect transistor fabrication 116 4.8 Integrated circuit packaging and testing 124 v vi Contents 5 Printed circuit board manufacture 130 5.1 Printed circuit board types 131 5.2 Printed circuit board substrate materials 133 5.3 Printed circuit board substrate manufacture 134 5.4 Printed circuit board fabrication procedures 136 5.5 Single-sided printed circuit board manufacture 146 5.6 Double-sided printed circuit board manufacture 148 5.7 Multilayer printed circuit board manufacture 153 6 Printed circuit board assembly 159 6.1 Hand assembly 160 6.2 Automatic component insertion 165 6.3 Assembly-related faults 173 6.4 Soldering techniques 176 6.5 Solder joint inspection and common soldering faults 187 6.6 Cleaning 191 6.7 Testing and reworking 192 7 Surface mount component assembly 197 7.1 Advantages of surface mount components 197 7.2 Surface mount component assembly 199 7.3 Adhesive application 200 7.4 Solder paste application 205 7.5 Component onsertion 209 7.6 Soldering techniques 213 7.7 Mixing surface mount with leaded components 220 7.8 Soldering quality 221 7.9 Testing 223 7.10 Reworking 224 8 Alternative technologies 226 8.1 Hybrid technology 227 8.2 Tape automated bonding 232 8.3 Silicon on silicon wafer-scale integration 234 8.4 Application-specific integrated circuits 235 8.5 Flexible circuits 238 References 241 Further reading 242 Index 243 Preface The sequence of events which led to the writing of this book started at a seminar on Manufacturing Technology in the Electronics Industry given by the Institution of Production Engineers in 1987. The seminar identified that the field of manufacturing engineering for the electronics industry was effectively missing from the vast majority of production engineering degree courses. The reason for this was that production engineering departments typically spring from mechanical engineering departments. This leads to a mechanical bias in the practical aspects of such courses. The consequence of this was that electronics companies could not recruit graduates with both relevant production engineering and electronic engineering backgrounds. This necessitated either recruiting production engineering graduates and giving them the necessary electronic engineering training, or giving production engineering training to electronic engineering graduates. A consequence of the lack of courses in a subject is that there is also a lack of relevant textbooks in the area, as most textbooks are intended to tie into courses. In the field of manufacturing technology for the electronics industry, existing textbooks tend to be highly specialized and mainly concerned with the fabrication of semiconductor devices. The book assumes no previous knowledge of electronics and keeps the actual electronic theory to a minimum. Where electronic com ponents are introduced, the emphasis is placed on their handling and packaging. The main subject areas addressed by this book are components, design, semiconductor device fabrication, printed circuit board manufacture, surface mount components, and non-standard devices and their associated technologies. Each area is viewed with respect to its impact on the manufacture of electronic devices. One of the major problems associated with any textbook which addresses the field of electronics is that technology is continually advancing at such a rapid pace that sections can rapidly become obsolete. The manufacturing aspect of the electronics industry is not in viii Preface practice changing as rapidly as the component technology. Many processes can accommodate changes in technology by operating on a smaller scale. The principles are the same except that process control needs to be much better. Processing faults which were tolerable on a larger scale can become unacceptable on a smaller scale. Modern society has an increasing requirement for cheap, reliable and increasingly complex electronic devices. This makes the efficient application of manufacturing technology to the electronics industry an important and challenging subject area which will be in great demand for the foreseeable future. Dr Phillip R. Edwards 1 Introduction to the electronics industry The electronics industry encompasses a wide range of different manufacturing processes and products. The most visible products of the electronics industry are consumer goods such as television sets, music reproduction systems and computers. These visible products represent a tip of the iceberg situation as a large part of the electronics industry is concerned with the manufacture of the component parts of products. The manufacture of switches, printed circuit boards, semiconductor devices and the assembly of complex computer systems are all aspects of the electronics industry. The fact that each of these activities would typically be performed by different organizations shows that there are few common factors across the electronics industry's component companies. An electronic product (excluding its packaging or casing), whether it be a simple transistor radio or a complex supercomputer, consists of two basic parts - the electronic components (transistors, resistors etc.) and the interconnections between the components. The electronics manufacturing industry is primarily concerned with interconnection technology - the methods of electrically joining the inputs and outputs of electronic components to form working circuits. Even the companies which manufacture the actual electronic components have to provide methods of connecting them to other devices. This book is primarily concerned with the manufacturing aspects of the electronics industry. In general a knowledge of the theory of electronics is not necessary for many manufacturing processes used for the manufacture of electronic products. The only exceptions to this are when a device's performance is sensitive to manufacturing-related parameters. This chapter is concerned with the global aspects of the electronics industry. A historical perspective is used to show the impact of rapidly 2 Introduction to the electronics industry changing technological progress on the industry. The increasing demands imposed by the market for electronic products is examined with respect to its effect on the electronics manufacturing industry. In order to appreciate the differing requirements and the resulting compromises which need to be reached for a typical product, the departmental structure and the interaction between departments are discussed for a typical manufacturing company. The functions of quality assurance and test engineering are so intimately entwined with almost every other function that they cannot be considered in isolation. An overview of the quality and test functions, and their interactions with other activities, is given. The actual quality and test activities are described alongside the descriptions of the individual manufacturing processes where appropriate. Chapter 2 is concerned with the individual electronic components. Components are grouped into families with related electrical or physical characteristics where appropriate. From the manufacturing point of view, the most important aspects of electronic components are those of their physical dimensions, their terminal connections, and their quality. Chapter 3 is concerned with the design processes, in particular the design of electronic circuits and the layout of circuits using computer aided design where appropriate. Chapter 4 describes the fabrication of semiconductor devices. Processing from design through to manufacture is covered completely. Chapters 5, 6 and 7 are concerned with the manufacture of complete printed circuit boards. Chapter 5 is concerned with the manufacture of the bare printed circuit board. Chapter 6 is primarily concerned with the assembly of conventional leaded components into printed circuit boards. Chapter 7 discusses the introduction of surface-mounted components and their impact on printed circuit board manufacture. Chapter 8 completes the discussion by describing some of the non standard electronic devices and interconnection methods. 1.1 A HISTORY OF THE ELECTRONICS INDUSTRY The electronics industry has evolved very rapidly since its beginnings. The enormous advances in technology, particularly since the late 1950s, have imposed considerable pressures towards change. In fact the progress of change is itself increasing, which makes obsolescence a serious problem. A good perspective of this rapid evolution, and how it has