Buried Components in Printed Wiring Boards

Abstract

ABSTRACT The original concept for using Printed Wiring Boards (PWB) was to accomplish the interconnect wiring necessary to connect all of the devices of an electronic circuit. Throughout the history of (PWB) there has been a consistent search for lower and lower cost to accomplish this interconnect wiring. At the same time, the capability of the PWB has increased to more than just a replacement for wires. This increased capability includes capabilities such as controlled impedance, heat management, power distribution, and integral capacitance and resistance. In more specialized cases active circuits to provide frequency dividers and filters are also a part of the PWB. Most of these capabilities were not considered to be “Buried Components”, when they really were! The two requirements of lower and lower cost per square inch, and more and more capability hidden in the PWB has in general been met well by the producers. However, with most of the capabilities mentioned above wanting to be incorporated at the same time in one low cost PWB, a problem has been created which needs further analyses. In general, cost of the PWB is looked at by itself, without regard to the cost of the assembly or system cost. This narrow view has hindered the adoption of new technologies because of their effect on PWB cost alone. In many cases, the payback from using new technologies in the PWB has a very positive effect on the assembly, test, yield, and reliability aspects of the overall product! A potential solution is to change the name of the product from PWB to IWB (Integrated wiring board). This change would reflect the same change that was made in the semiconductor industry when they went from individual transistors to IC's with many transistors, capacitors and resistors in one package.