Foreign matter on printed circuit board patterns was analyzed using an electron probe microanalyzer (EPMA).
It can be seen that copper has migrated from the cathode (negative) to the anode (positive).
A distribution of chlorine (Cl) can also be confirmed at almost the same position as the copper (Cu).

Metal Migration on Printed Circuit Boards

Electron Probe Microanalyzer

Electron Probe Microanalyzer

An electron probe microanalyzer irradiates a sample with a finely focused electron beam to reveal the element composition of small parts. It allows the highly sensitive analysis of elements in micron-scale regions on the sample. Simultaneously using submicron-order quantitative analysis and SEM images allows applications to shape inspections. Cause analysis can be performed immediately when foreign matter is discovered.