Increased operating temperature and power cycling capability
The layers between the chips and the DCBs are those solder joints in a power module next in size after the solder layer in baseplate modules between the DCB substrates and the baseplate. Substituting these solder layers with a sintered joint can increase the operating temperature and power cycling capability and the heat dissipation from the chips can be further improved.
The SKiNTER technology launched for power modules by SEMIKRON in 2007 utilizes a fine silver powder at a temperature of around 250°C under high pressure, sintered to a silver layer of very low porosity, connecting chip and DCB surface extremely stably up to the melting point of silver at 962°C.
This melting temperature - four times higher compared to an SnAg solder layer - is the key for the two to three times better power cycling capability and long-term reliability of sintered components at high operating temperatures. Today’s standard SnAg solder ages already at 125°C with thermal stress.
The images below illustrate the achievable improvements with an example: In a soldered module aging of the solder leads to increased chip temperatures much earlier than in the sintered modules due to deteriorated heat dissipation. The module with the sintered joint between the chip and the DCB has a longer service life.
Due to a layer thickness of at least 70% less than a solder layer and about three times better thermal conductivity, an approximately 15 times lower thermal resistance results for the sintered layer. Further advantages over a solder connection are, for example, a lower coefficient of thermal expansion and higher tensile strength.