Origins of Ion Migration Patterns in Printed Wiring Boards.
Tsutomu Tsukui, Youji YOKOSUKA · Circuit Technology · 1994
It is impossible to do design for printed wiring boards without evaluation of insulation reliability according to the advances in finer pitch printed wiring boards.This main reason giving rise to insulation deterioration is ion migration.Therefore, this study forcuses on the origin and development of this migration.The result of this study were; (1) The probability of ion migration was dependent on the type of metal.This was understood by refering to the ionized sphare of the potential-pH diagram.(2) Ion migration patterns were classified as two types.The most frequent type originated from the anode electrode.The second type originated from the cathode electrode.This type originated from the adhesive layer which had lower insulation resistance or from the reduced insulation at the surface caused by dew condensation.1.