Thermal Interface Materials for Power Electronics Applications

Sreekant Narumanchi, Mark Mihalic, Kenneth Kelly, Gary Eesley

Research output: Contribution to conferencePaperpeer-review

153 Scopus Citations


In a typical power electronics package, a grease layer forms the interface between the direct bond copper (DBC) layer or a baseplate and the heat sink. This grease layer has the highest thermal resistance of any layer in the package. Reducing the thermal resistance of this thermal interface material (TIM) can help achieve the FreedomCAR program goals of using a glycol water mixture at 105°C or even air cooling. It is desirable to keep the maximum temperature of the conventional silicon die below 125°C, trench insulated gate bipolar transistors (IGBTs) below 150°C, and silicon carbide-based devices below 200°C. Using improved thermal interface materials enables the realization of these goals and the dissipation of high heat fluxes. The ability to dissipate high heat fluxes in turn enables a reduction in die size, cost, weight, and volume. This paper describes our progress in characterizing the thermal performance of some conventional and novel thermal interface materials. We acquired, modified, and improved an apparatus based on the ASTM D5470 test method and measured the thermal resistance of various conventional greases. We also measured the performance of select phase-change materials and thermoplastics through the ASTM steady-state and the transient laser flash approaches, and compared the two methodologies. These experimental results for thermal resistance are cast in the context of automotive power electronics cooling. Results from numerical finite element modeling indicate that the thermal resistance of the TIM layer has a dramatic effect on the maximum temperature in the IGBT package.

Original languageAmerican English
Number of pages10
StatePublished - 2008
Event2008 11th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, I-THERM - Orlando,FL, United States
Duration: 28 May 200831 May 2008


Conference2008 11th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, I-THERM
Country/TerritoryUnited States

Bibliographical note

For preprint version, see NREL/CP-540-42972

NREL Publication Number

  • NREL/CP-540-44056


  • ASTM D5470
  • Greases
  • IGBTs
  • Laser flash
  • Modeling
  • PCMs
  • Steady state
  • Thermal resistance
  • Transient


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