In order to study the generation mechanism of electrochemical migration in a printed wiring board, paper/phenol-resin composites with and without an adhesive layer, epoxy resin, and a laminate of epoxy resin and a paper/phenol-resin composite were aged at 85 °C and 85% relative humidity (RH) with and without application of a DC voltage, and the space charge distributions in the samples were observed by the pulsed electroacoustic method. In the case of the composite with the adhesive layer, a large amount of negative charge is induced at the interface between the composite and the adhesive layer on the anode. It was found that such formation of space charge enhances the electric field intensity at the anode. The reason for this is because the conductivity is much lower in the adhesive layer than in the composite. Electrochemical migration does not occur when the same electric field is applied to the composite without the adhesive layer, whereas it does occur if the adhesive layer was replaced by epoxy resin with a similar conductivity to the adhesive layer. These results clearly indicate that electrochemical migration generates because the electric field at the anode surface is enhanced due to the low conductivity of the adhesive layer.
|ジャーナル||IEEJ Transactions on Electrical and Electronic Engineering|
|出版ステータス||Published - 2011 5|
ASJC Scopus subject areas
- Electrical and Electronic Engineering