IGBT chip current imaging system by scanning local magnetic field

•An IGBT/power diode current distribution imaging system was demonstrated.•An automatic current imaging system based on the tiny coil sensor scanner.•The system scans current distribution without any changes of the chip connections.

An IGBT/power diode current distribution imaging system was demonstrated. This system can capture current redistribution or oscillation inside or among chips on a DBC-level sub-module. It can perform failure analysis of power semiconductors by detecting problems such as nonuniform current distribution between bonding wires. The system scans the chip’s shape using a laser sensor and then records the local magnetic field near the bonding wire using a 4-axis robot coil sensor. The coil sensor has two pair of Cu patterned spiral coils symmetrically arranged on both sides of a 60-μm-thick polyimide film. The system enables the analysis of destructive current concentrations of the entire chip, among chips or a part of the chip under high current or high voltage switching conditions, without making any changes or disassembling the chip connections.