Fraunhofer Institute for Reliability and Microintegration IZMSilver Sintering
The demands on electronic and mechatronic systems are increasing steadily. Today, such systems are even expected to operate reliably at temperatures of up to 300°C. Silver sintering is an ever more popular means of achieving this and represents an alternative to conventional solder processes in power electronics.
In conventional sintering, fine-grained, powdery basic materials are joined together under high pressure at a temperature far below melting. A sintered silver compound layer is created using silver nano- or microparticles alloyed with organic additives. Using diffusion mechanisms, the silver particles can be joined at temperatures as low as 200 °C, even though the actual melting point of elemental silver is 961 °C. The driving force behind this phenomenon is reducing the surface tension of the particles. These joints are significantly more reliable than standard solder joints, as the melting point of the sinter layer is far higher than the operating temperature of power electronic components. Silver sintering is particularly popular for components that need good thermal and electrical interconnection and are used in high-temperature operating environments.