Author: Chris Hunrath, Insulectro Vice President of Technology
ABSTRACT
The Printed Circuit Board industry has been dominated by fiberglass cloth-based materials for many years. Good reasons include cost, as well as thermal and mechanical stability. Glass fabric provides a substrate for manufacturing where the resin of choice is applied and then “dried” for use in the PCB manufacturing process. The fabric also supports cutting and handling of the uncured product.
Technically, PCB materials are composites (heterogeneous solids containing two or more materials that are combined where each retains its characteristic properties). The glass provides mechanical and thermal stability as well as dielectric spacing. The resin enhances the mechanical and dielectric properties and provides a bonding function.
Over the history of printed circuit boards, many different resin systems have been developed, driven by the ever-increasing need for better electrical and thermal performance.
In some cases, mixing of resin types is used to balance cost and electrical performance, but these structures still typically use glass fabric as a foundation.
New high performance resin systems are almost always applied to the same glass cloth that has been used for decades. While some of the properties are improved, limitations from the glass tend to carry over to the newer resins systems.
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