In-Plane and Out-of-Plane Coefficient of Thermal Expansion Characterization of New High-Performance Printed Circuit Boards Using Dilatometer and Thermomechanical Analysis

This paper provides both in-plane and out-of-plane coefficient of thermal expansions (CTEs) of a high-performance QUATREX 5010 epoxy/Kevlar-120 fabric composite printed circuit board (PCB). Although both a quartz push-rod dilatometer and a thermomechanical analyzer (TMA) were used to measure the in-plane CTEs, the results indicate that the dilatometer is a better choice for accurate, precise determinations, especially for Kevlar/epoxy composites that had a CTE of 3.5 ppm/°C in the x and y direction. Based on our past experience testing various composite PCB materials based on E-glass, quartz, and Kevlar reinforcements, epoxy, polyimide, BT/epoxy, cyanate ester, and so forth, we recommend the dilatometer for accurately measuring the in-plane CTEs of Kevlar- and quartz-reinforced PCBs, which generally are below 9 ppm/°C. The TMA method, which is a faster and easier method than the dilatometer method, can be used reliably for accurately measuring the in-plane CTEs of E-glass-reinforced PCBs, which generally range from 12 to 16 ppm/°C.