Accelerated degradation testing of coating of PCB under humid heat env

Printed circuit board (PCB) is the carrier of electronic components. Its coating is the first barrier for protecting itself. If the coating is damaged, the performance of printed circuit board will decrease rapidly until failure. Therefore, the coating plays an important role to the entire printed circuit board. In this paper, we designed an accelerated degradation test under humid heat environment for a typical kind of coating (Parylene C). And chose insulation resistance, moisture absorption and surface morphology as its test indexes. At last, we estimate the coating´s failure time based on the degradation of insulation resistance.