TANAKA Develops Active Brazing Filler Metal for Power Devices

August 20, 2021 by Darshil Patel

TANAKA Precious Metals develop active brazing filler metal for high-power circuits that provide high heat dissipation, reduced processing time, and costs.

Each electronic component generates a certain amount of heat during operation that can have adverse effects on the performance and reliability of the device itself, as well as the whole system. It is necessary to keep the junction temperature of the semiconductor devices well within the limits set by the manufacturer to ensure the reliability and longevity of components. Thermal management technologies available today take care of this heat generated in electronic devices and circuits to ensure proper operation. But the problem of thermal management is getting severe due to the tendency of electronic sectors to reduce the package size of components. The decrease in package size increases the device density, which complicates thermal management. 

To cater to such complex management needs, appropriate measures must be taken ranging from heat sinks, thermal fillers, heat spreaders, cold plates, fans, heat pipes, compact heat exchangers, and many more methods. These components are used at the system level, and heatsinks are the most widely used thermal management components. 

Most of today's power electronic systems require increased heat sink efficiency. To address these needs, TANAKA Precious metals, a Japan-based manufacturer of industrial products using precious metals such as platinum, gold, silver, etc., have developed an active brazing filler metal/copper composite material that reduces processing times.

Brazing refers to the metal joining process in which base metals are joined without exceeding their melting point using a metal filler which, when heated, liquefy and melt to flow into the space between the two bases, creating a brazed joint.

Proposed processing of active brazing filler metal. Image courtesy of TANAKA.

The developed product is a composite cladding of copper with active brazing filler metal on one side. It can be joined directly to any material, including ceramics and carbon materials, making it suitable for use in ceramic substrates and next-generation heat sinks for power devices. This kind of formation is difficult to achieve with the existing etching process. Moreover, the material does not contain any solvents. So there is no residue, so volatile organic compounds are not released, and bonding reliability is improved.

The brazing filler thickness, using this new process, can be 10 micrometers or less. This means that as compared to earlier filler metal, silver bullion costs can be reduced by half or more. Plus, the copper metal being compounded, the pattern can be easily formed by setting the material, reducing processing costs. The brazing times are also reduced significantly, which leads to energy savings and reduced environmental impact.

Overall, the new product and its processing approach provide both high heat dissipation and reduced processing time.


How Does This Composite Filler Aid Power Devices?

The number of electronic components installed on a system is constantly growing. This growth has made thermal management of power devices not only more difficult but far more critical. The performance of electronic systems used in automotive industries and other industrial conditions is limited due to heat. Moreover, in high-output laser diodes, the only thing that is stopping the creation of high-power lasers is the lack of thermal management. As a result, individual components with high heat dissipation, high heat resistance, and high bonding reliability, and developing materials that are compatible with further miniaturization are urgent priorities for the industry. 

To meet these requirements, increasing the thickness of copper plates becomes necessary, and the newly developed product enables the formation of electrodes on a thick copper material to enhance the bonding reliability and contribute to higher heat dissipation.