When the Printed Circuits Handbook 1st Edition was published in 1967, it contained 16 chapters by 11 authors. It described the basic elements of the plated-through-hole (PTH) printed circuit process in the same sequence that was found in fabrication shops of the day. The fifth edition, to be published later this summer, will have 61 chapters and 41 authors. The technology, as well as the industry, has grown, changed, and become more complex over the years, and the book has had to grow and change to remain a single volume source of comprehensive information on the entire set of printed circuit processes. The information presented still starts with the basics and goes to the more technologically advanced.
However, it is sometimes difficult to isolate the fundamental elements of the printed circuit process and how these generic steps lead logically, and sequentially, to a finished circuit board, without getting bogged down in the technical details of each one. In addition, new technologies and process steps have been developed to allow the industry to respond to the needs of new component packages, often obscuring the underlying basics.
This issue of The Board Authority provides the reader with a unique resource for understanding the overall printed circuit process. It has specific introductory information on the fundamental processes that have been, and remain, the foundation of the entire technology. In addition there are articles that provide supplemental details on critical process elements.
It will be a valuable reference for:
- Those who need to know how the pieces of the printed circuit puzzle fit together, and what the important issues are when designing a board, or contracting for a board to be built.
- Those who deal with printed circuit issues routinely and need a concise summary of the process that will provide a common background in discussions on the subject.
- Those who are new to the practical world of board fabrication, and need an accessible source of basic information before being immersed in details or advanced technology.
We have developed a "roadmap" to PTH fabrication that leads the reader step-by-step through the basic multilayer fabrication process. The purpose of each process element is described along with an outline of the technology involved. In this way we feel the overall picture of what is actually involved in making a printed circuit emerges.
To accomplish this we have broken the subject into two parts:
- An overview of the Printed Wiring Board (PWB) fabrication process, along with an overview of multilayer constructions.
- Articles on main issues and elements of critical process steps.
In developing this material we have relied on two basic sources. Many of the articles on specific process steps have been developed from chapters prepared for the next edition of The Printed Circuits Handbook. More detailed discussions of these issues can be found there.
The "Overview" has been developed, with permission, from "Printed Wiring Board Pollution Prevention and Control Technology" (EPA document, 744-R-98- 003) prepared for the EPA with printed circuit industry members and technology vendor assistance and information. The original objective was to provide the industry, and users, with information on how to make choices in the technology to help fabricators develop and maintain environmentally responsible processes. The result not only achieved that goal, but also produced an excellent summary of the PWB process.
While the preferred term of "printed wiring board" is primarily used in this issue, we also use the term "printed circuit," interchangeably. "Printed circuit," for better or worse, has entered the world's language as the most used name of the process we are describing here.
CLYDE F. COOMBS, JR. |
Fabrication Basics Issue