Detection of ion migration in composites for printed circuit boards by the pulsed electroacoustic method

Pulsed electroacoustic (PEA) method is applied as a nondestructive technique to detect ion migration that progresses to the thickness direction in insulation composites for printed circuit boards. In both cases of a paper/phenol-resin composite and a glass/epoxy-resin composite, penetration of Cu migration into the bulk after aging was confirmed. Namely, a shift of the peak location of positive charge, which corresponds to the progress of migration in the aged composite, is observable by the PEA method.