News

Mitsubishi Materials Corporation ("MMC") utilized its proprietary copper powder manufacturing technology to develop a new type of "sintering copper bonding material" using submicron copper particles, which enable sintering bonding at lower temperatures than conventional copper powders. The material is provided in the form of copper sheets for a wide range of applications.

■Background and purpose of development

High-power modules, such as those used in automotive and railway inverters, require low heat resistance, high heat dissipation capability, and long-term reliability at the joints due to the high-temperature operation and large current demands of semiconductor devices.
Conventionally, pressure-type sintering bonding materials primarily composed of silver have been widely used. However, they have posed challenges such as rising material costs due to soaring silver prices and the tendency for residual decomposition gases from organic solvents and resin components to remain during large-area bonding, leading to bonding defects.
Against this backdrop, MMC has been working to develop copper materials to resolve the challenges associated with conventional silver sintering bonding materials, namely high cost and reliability in large-area bonding. Specifically, MMC is working to advance material design by establishing an integrated development system that covers everything from the synthesis of copper powder to the design of sintering copper materials. As a result, MMC has developed submicron copper particles with a particle size of 100 to 200 nm, extremely low levels of metallic impurities, and high sinterability, due to our unique particle surface coating design. Using these particles, we have developed copper sheets that combine low-temperature bonding, large-area compatibility, and high reliability, serving as an alternative to conventional silver-based sintering materials.

■Features

MMC's proprietary sintering copper bonding material, which utilizes copper particles, possesses low-temperature sintering properties comparable to those of silver sintering materials despite being made of copper. This next-generation bonding material enables bonding at temperatures between 200 and 250°C within short durations under a nitrogen atmosphere. Copper sheets offer the following features:

• Excellent handling, enabling easy transport and setup. This eliminates the need for the printing and drying processes for organic components, which are essential for pastes, thereby shortening the process.
• Compared to paste types, it contains fewer organic components, enabling uniform bonding even on large-area power modules while suppressing void formation.
• Higher bonding quality and reliability due to its greater thickness compared to paste types.

MMC plans to start providing copper sheet samples sequentially for various applications. We will contribute to improving the heat resistance, efficiency, and power saving of high-power modules for wide applications, including automotive and railway uses.

MMC Group has established "For people, society and the earth, circulating resources for a sustainable future" as Our Commitment, and strives to become a company dedicated to creating the future through resource circulation, while working to realize Our Commitment and enhance corporate value.

[Related information]

WITH MATERIALS - Mitsubishi Materials' Web Media
What type of material is "sintering copper bonding material"
URL: https://withmaterials.mmc.co.jp/en/131

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