Infineon steps up module performance with precision-applied heat conducting paste

April 30, 2013 // By Graham Prophet
Thermal Interface Material (TIM) developed by Infineon Technologies for the reduction of contact resistance between the metal surface of power semiconductors has yielded, using EconoPACK + and the D Series modules, substantially improved conductivity.

Heat conducting paste might appear to be a mature product, but Infineon's new formulation has encouraged the company to roll it out as an automatic application in the assembly of various ranges of power semiconductor modules. In the first quarter of 2014 the “62mm”, EconoDUAL 3 and PrimePACK 2 product groups are going to be available with TIM pre-applied. Toward the end of the first half of 2014 the EconoPACK 4 and PrimePACK 3 modules as well as the Econo 2 and 3 modules are to be available with the material. The launch of the TIM-applied production series Easy 1B and 2B, Smart 2 and 3, and IHM / IHV is planned for 2015.

Infineon has set up a production line for applying TIM to the modules at the Hungarian Backend site for power electronics in Cegléd. The thermally conductive paste is applied to the modules using a stencil-printing process. An elaborate quality assurance procedure integrated into the fabrication process guarantees that no air is trapped when joining the module and the heat sink. Special technical processes and machines were developed just for the fabrication process.

“TIM and the process developed by us for applying the paste makes it possible for the first time to assure a maximum value instead of typical values,” says Dr. Martin Schulz, the manager responsible for qualification in Application Engineering at Infineon Technologies AG. “Against the background of increasingly higher power densities, the thermal budget can now be planned more precisely in the design stage of applications.”

TIM allows significantly reduced contact resistance between the metal surface of the power semiconductor and the heat sink. The transfer resistance from module to heat sink for the new EconoPACK™ + D Series is reduced by 20%; this optimised thermal transfer improves the lifetime and reliability of modules. As the material functions reliably from the start, a special burn in cycle is not necessary as has been the