Development of a flexible epoxy copper clad insulation for etched circuit boards

The material discussed in this paper was developed in response to a specific need inherent in the design of certain electronic modules. One such design is shown in Figure 1. Initially a thin (.005 inch) rigid epoxy-glass circuit board was used. The circuit area of this board carried circuitry on both sides of the board and was bonded to the anodized aluminum heat sink by means of a thin epoxy glass prepreg material. Bonding of the board to the heat sink was done in a laminating press. The cured prepreg material between the board and the heat sink served not only to bond but also served as electrical insulation between the bottom layer of circuitry and the aluminum.