Three-dimensional space charge measurements of printed circuit boards

Investigated the ion migration phenomena of printed circuit boards, and found that the pulsed electroacoustic space charge measurement system can monitor the copper ion migration into the epoxy resin from the electrode surface. The migration, however, can proceed in any direction in the specimen simultaneously; therefore, it should be measured in three dimensions. We have measured typical test pieces of polyimide printed circuit boards and metal-based epoxy resin insulated printed circuit boards by a newly developed three-dimensional pulsed electroacoustic method. The experimental results show that the space charge density varies in the lateral direction when ion migration occurs in the specimen