Utilizing thermal fatigue testing to differentiate the performance of epoxy materials at various glass transition temperature levels

A common method for understanding the thermal performance of epoxy laminate materials is to analyze the glass transition temperature using instruments such as differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermomechanical analysis (TMA). In order to characterize the long‐term performance of a finished printed circuit board, more advanced reliable test methods have been developed. This paper will discuss interconnect stress testing (IST), an accelerated fatigue test used for evaluating the failure modes of a printed circuit board (PCB) interconnect. IST utilizes a DC current to heat the PCB to the recommended temperatures within the interconnect. The plated through hole integrity and the post‐interconnect integrity can be monitored simultaneously. The test matrix compares the performance of various AlliedSignal epoxy laminate materials as a function of glass transition temperature (Tg) and board design.