Sumitomo Bakelite Develops G785 Series High-Tg Epoxy Molding Compounds with Industry-Leading 230°C Tg for Next-Gen SiC Power Modules

Sumitomo Bakelite Co., Ltd. Japan

Overview

Sumitomo Bakelite has developed the ‘G785 Series’ of high-Tg epoxy molding compounds for next-generation SiC power modules, achieving an industry-leading glass transition temperature (Tg) of 230°C. This material resolves the trade-off between high Tg and low stress by suppressing modulus increase, minimizing warpage, and preventing delamination and resin cracking. This significantly enhances packaging reliability for SiC devices operating at high temperatures, critical for EV and renewable energy applications.

In Depth

Key Findings

Sumitomo Bakelite Co., Ltd. has successfully developed the ‘G785 Series’ of high-Tg epoxy molding compounds (EMCs) for next-generation Silicon Carbide (SiC) power modules, boasting an industry-leading glass transition temperature (Tg) of 230°C. This breakthrough material addresses the long-standing challenge of balancing high Tg with low stress, dramatically improving the long-term reliability of SiC devices operating in high-temperature environments.

Technical / Clinical Details

The G785 Series uniquely suppresses the excessive modulus increase typically associated with conventional high-Tg materials after curing. This proprietary technology allows the material to achieve an exceptionally high Tg of 230°C while effectively mitigating thermal stress generated within the package. As a result, common reliability issues such as warpage, delamination between the die and lead frame, and resin cracking—which often occur during power module manufacturing or high-temperature operation—are minimized. SiC power modules are designed for higher operating temperatures (typically above 200°C) compared to Si devices, and the resulting stress from coefficient of thermal expansion (CTE) mismatch directly impacts device lifespan. The G785 Series fundamentally resolves this CTE mismatch-induced stress problem, enabling high-reliability packaging. Furthermore, it possesses excellent electrical insulation, moisture resistance, and heat resistance, ensuring stable operation under severe environmental conditions.

Background & Context

SiC power devices are gaining significant attention as key components for next-generation power converters in electric vehicles (EVs), renewable energy systems, and industrial equipment, owing to their high power efficiency and potential for miniaturization. However, because SiC devices operate at higher temperatures than Si devices, packaging materials demand superior heat resistance and reliability. Historically, high-Tg materials offered excellent thermal stability but suffered from a trade-off: increased rigidity after curing led to higher internal stress. This challenge has been a major impediment to improving the performance and reliability of SiC power modules. Sumitomo Bakelite’s G785 Series overcomes this technological barrier, accelerating the adoption and advancement of SiC power modules.

Strategic Significance & Outlook

The introduction of the G785 Series holds the potential to redefine packaging technology standards in the SiC power module market. This innovative material will contribute to enhancing product performance and reliability across various applications, such as extending EV driving ranges, shortening charging times, and improving the efficiency of solar power generation systems. Sumitomo Bakelite plans to deploy the G785 Series globally, providing strong material support for the development of next-generation power electronics. Through this, the company is expected to further solidify its leadership as an advanced materials supplier and contribute to the realization of a sustainable society.