A study for open circuit failure of PCB with direct plating using conductive polymers

Driven by the pressure of environment protection and cost reduction, direct plating as a new alternative process had been used to replace the conventional electroless copper in some factories. It is necessary to realize the potential reliability problems when using this completely plating method. An internal circuit open failure case in PCB with direct plating using conductive polymers was studied in this paper. Based on electrical function test, X-ray inspection, cross section analysis, scanning electron microscopy and energy dispersive spectrometry (SEM & EDS), and coefficient of thermal expansion in the Z-Axis (Z-CTE test), the failure is attributed to the innerlayer separation caused by poor bond of innerlayer/electroplating copper interface which can not withstand the thermal stress under high soldering temperature and operating condition.