In-situ Charge Observation in Insulation Layers of Metal-base Printed Circuit Boards

We have developed in-situ space charge measurement system during ageing tests of printed circuit boards by the pulsed electroacoustic method. It can observe space charge profiles at 358 K (85°C) and 85 %RH. Experimental results suggest that internal space charge behaviour is strongly affected by the humidity. This technique should contribute to evaluate test methods of insulation layers as well as to investigate the ageing process.