Stability Investigation of High Heat-Resistant Resin under High Temperature for Ultra-High Blocking Voltage SiC Devices

Abstract

The reliability of three kinds of high heat-resistant resins has been evaluated under high temperatures. These resins were applied to insulation substrates and a high temperature storage test has been carried out. The insulation performance of the resins was evaluated by applying 20 kV between a pair of electrodes on the substrate covered with resin. The insulation performance at 20 kV was maintained in samples with two of the three kinds of resins for 1,000 hours at 225oC. In a higher temperature storage test at 250oC, samples with one of the kinds of resin were not able to maintain insulation of 20 kV for 200 hours, while the two remaining resins were not able to maintain the insulation for 1,000 hours. In most samples that were not able to maintain the insulation, cracks or detachments were seen. Hardening caused by oxidation of the resin and differences in the coefficient of linear thermal expansion (CTE) are considered as causes of the cracks or detachments. It is thought to be necessary to lower the CTE of the resin and inhibit its oxidation in order to use it at more than 250oC for long periods of time.

High Junction Temperature and Low Parasitic Inductance Power Module Technology for Compact Power Conversion Systems

“…Recently, several research groups have investigated high-temperature encapsulants and reported that heat resistance was still at a level below 800 h for storage at 250°C [4], [8], [41], [42]. More thermally reliable encap- sulants have to be developed for next-generation compact SiC power modules [41].…”

“…More thermally reliable encap- sulants have to be developed for next-generation compact SiC power modules [41].…”

Packaging Techniques for Compact SiC Power Modules Operable in an Extended Tj Range

“…However, they are designed for use in a temperature range below 175°C. Recently, several research groups have investigated high-temperature oriented encapsulants, reporting that the heat resistance was still at level of less than 800 hours for storage at 250°C (6,28,29). More reliable encapsulants have to be developed for next-generation compact SiC power modules.…”