Achieving high reliability in service is the key issue in today’s high density electronic circuits. The voltage applied to the electronic circuit plays a very important role in electrochemical reliability. Insulation Resistance (IR) measurement has been widely used to predict and evaluate the reliability of electronic circuits. The test voltages utilised for existing IR measurement are typically only up to 100V. With the significant increase in electrification of transport and corresponding increases in the voltages that electric vehicles operate, IR measurements need to be conducted at higher voltages to understand any potential new failure mechanisms.
NPL recently commissioned 1000V IR test facility has be used to characterise dendrite formation on PCB surface and Conductive Anodic Filament (CAF) formation inside PCBs at 1000V. Specially designed PCBs with different finishes and comb patterns of different pitches have been reflow soldered using different solder pastes and IR tested at 1000 V. The effect of the increased test voltages on dendrite failure will be discussed. The results will also be compared with the CAF failures generated by NPL on similar pitch of via patterns.