TSEP-Sensitivity Study to Analyze the Soldering Process of a Power Diode

The use of SAC305 solder for connecting electronic components on a printed circuit board is standard for the microelectronics industry. It is well-known that the quality of solder joints decreases when voids are formed, as it impairs the heat dissipation and hence the reliability of the device. In this work, a sample series of 12 power diodes was analysed, regarding their voids in the solder and their thermal behavior. The integrity of the solder joints between the power diode and the FR4-based printed circuit board was investigated by X-ray tomography. Their void formation was studied in terms of their overall percentage, size and location. The thermal resistance, hence the thermal behavior, of the power diodes was obtained by a temperature-sensitive electrical parameter (TSEP) measurements. The correlation between the thermal data and the void formation promotes the awareness of the void's influence on thermal behavior. The findings were supported by finite element simulations.