Printed Circuits Handbook

Printed Circuits Handbook

Printed Circuits Handbook

Article Type: Book review From: Circuit World, Volume 36, Issue 1

Edited by Clyde F. Coombs Jr,6th ed.,McGraw-Hill Professional Publishing,New York, NY,2007,ISBN 978-0-07-146734-6

For anyone who has an interest in printed circuit board (PCB) technology, either as an academic or someone working in the industry, the name of Clyde Coombs will already be well known. “Coombs” is the word that many people use when referring to what has become the PCB industry's information bible. More correctly known as the Printed Circuits Handbook, this work has been in production for more than 30 years and it is the current sixth edition that is the subject of this review. Although the work's Editor-in-Chief is indeed Clyde Coombs, the preparation of this large and highly detailed manuscript has also involved a huge input from a large team of international experts. To give some idea of the scale of the work involved, there are over 40 named authors that have contributed in some way to the book's 67 chapters and which run to a grand total of somewhere around 1,000 pages. This latest version attempts to bring the technology right up to date and includes a range of new topics including the key, and highly topical, subject of lead-free. There are new sections on lead-free PCB design and manufacturing techniques, lead-free materials and lead-free reliability modelling. Considering the range of problems and issues that can be encountered when moving to lead-free, these sections are a welcome addition that will prove to be very useful. Given the growth in the use of high-density interconnection (HDI) approaches, the book also now includes a section on HDI best practices. The rapid evolution and introduction of new technologies into the PCB industry means that new editions of standard works such as this one are increasingly needed if they are to convey up-to-date information to their readers. This is a fact acknowledged by the editor in the preface to the book, where he states that over 75 per cent of the chapters have either been revised or are new to this edition. The sixth edition therefore contains the most new information since the first edition appeared in 1967.

The book is conveniently divided into a number of key sections (called parts) and begins with a single chapter section on “Lead-free legislation”. There then follow four chapters in a section covering “printed circuit technology drivers” which cover electronic packaging and high-density interconnectivity, semiconductor packaging technology, advanced component packaging and types of printed wiring boards. The following section is on “Materials” and has no less than seven chapters covering all aspects relating to base laminate materials. Section 4 covers “Engineering design” and this has nine chapters giving details on a wide range of topics including the PCB design process, electrical and mechanical design parameters, PCB design for thermal performance and information formatting and exchange. This section concludes with a chapter on embedded components, a topic that is, and continues to be, increasingly important as performance demands from both assembled electronics and their interconnects become more and more challenging.

Section 5 is another relatively short one, with two chapters being devoted to “HDI”. This is balanced by the following section on “Fabrication” which has 12 chapters covering all aspects of the manufacturing process, including all of the well-defined stages such as imaging, electroplating, direct plate, solderable finishes, solder, etching, drilling, machining and routing.

At this point, it is worth noting that, despite the huge amount of information that has already been provided, the halfway point in the book has only just been passed and there are still another 30 chapters remaining! Section 7 is devoted to “Bare board testing” and its four chapters cover testing objectives and definitions, methods and equipment with a final chapter devoted to special testing methods for HDI bare boards. Two chapters on “Board assembly” then follow in Section 8 and these cover assembly processes and conformal coating. After this, the book moves on into the very important area relating to soldering and there are two sections, comprising seven chapters, that have a focus on “Solderability technology” and “Soldering materials and processes”, respectively. Within these two sections, there are chapters covering most of the relevant subject matter from soldering fundamentals to repair and rework. Between these, there is ample coverage of soldering materials and both conventional and lead-free alloys are covered, as well as fluxes, soldering techniques and incoming inspection methods. There is a little overlap here as there are two separate chapters covering fluxes: they could probably have been combined into a single chapter but in allocating two chapters it has been possible to provide additional and complementary detail. On reaching Section 11 and Chapters 49 and 50, the subject matter moves from soldering to “Non-solder interconnections”, with the chapter headings being “Press fit interconnection” and “Land grid array intereconnect”.

What might be expected to be the final three sections of the book cover the very important subjects of “Quality”, “Reliability” and “Environmental issues”. Section 12 on “Quality” has five chapters covering another wide range of subject matter from acceptability and assembly inspection to design for testing and loaded board testing. The next section is on “Reliability” and has four chapters. Its first chapter is interestingly, and some might say appropriately, devoted to the relatively new reliability issue known as conductive anodic filament formation. This important failure mechanism has become more apparent with the move to lead-free assembly and it is good to see the subject given prominent and detailed coverage. The other three chapters in this section cover reliability aspects including component to board reliability and the impact of lead-free solders. Section 14 has single chapter covering “Process waste minimization and treatment”. This is a subject area that has also gained much more importance in recent years, especially with the increasly stringent legislation that is impacting producers in various parts of the world, especially Europe and the USA and it is one that may need expanding in future editions.

It is at this point that one might expect the book to have reached it natural conclusion but, as an added bonus, there then follow six further chapters dedicated to the more specialised area of “Flexible circuits”. These final six chapters, which are almost equivalent to a book in their own right, give a detailed description of all aspects of the flexible circuit manufacturing process from materials and applications, through design and manufacturing, to quality assurance. There are also chapters on special considerations pertinent to flexible circuits and coverage of multilayer flex and rigid flex circuits. The book finally ends with an “Appendix” giving a summary of key component, material, process and design standards, followed by a “Glossary” of terms and a very detailed “Index”.

In conclusion then, this book is the latest in a long line of Printed Circuit Handbooks that have served the PCB industry well for more than 30 years. With its unsurpassed level of detail and over 500 figures, tables and illustrations, this book provides the level of information that will satisfy the needs of even the most experienced PCB experts. The rapid pace of change in PCB technology means that new editions are increasingly required in order to be relevant for today's manufacturers and researchers. This latest version has been heavily updated with major revisions of existing chapters and perhaps more importantly with the addition of new chapters. The editor and his team are to be congratulated for producing another valuable tome that will undoubtedly benefit the great number of people around the world who share an interest in PCB technology.

Martin GooseyOctober 2009