Optimization of thermal interface materials for electronics cooling applications

Thermal interface materials (TIMs) are used in electronics cooling applications to decrease the thermal contact resistance between surfaces in contact. A methodology to determine the optimal volume fraction of filler particles in TIMs for minimizing the thermal contact resistance is presented. The method uses finite element analysis to solve the coupled thermo-mechanical problem. It is shown that there exists an optimal filler volume fraction which depends not only on the distribution of the filler particles in a TIM but also on the thickness of the TIM layer, the contact pressure and the shape and the size of the filler particles. A contact resistance alleviation factor is defined to quantify the effect of these parameters on the contact conductance with the use of TIMs. For the filler and matrix materials considered-platelet-shaped boron nitride filler particles in a silicone matrix-the maximum observed enhancement in contact conductance with the use of TIMs was by a factor of as much as nine.

[1]  G. L. Solbrekken,et al.  Thermal modeling and experimental validation of thermal interface performance between non-flat surfaces , 2000, ITHERM 2000. The Seventh Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.00CH37069).

[2]  Viggo Tvergaard,et al.  Analysis of tensile properties for a whisker-reinforced metal-matrix composite , 1990 .

[3]  Patrick E. Phelan,et al.  Percolation theory applied to the analysis of thermal interface materials in flip-chip technology , 2000, ITHERM 2000. The Seventh Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.00CH37069).

[4]  N. F. Dean,et al.  Experimental testing of thermal interface materials on non-planar surfaces , 1998, Fourteenth Annual IEEE Semiconductor Thermal Measurement and Management Symposium (Cat. No.98CH36195).

[5]  R. E. Simons,et al.  An Approximate Thermal Contact Conductance Correlation , 1993 .

[6]  Ravi Prasher,et al.  Surface Chemistry and Characteristics Based Model for the Thermal Contact Resistance of Fluidic Interstitial Thermal Interface Materials , 2001 .

[7]  B. Mikic,et al.  THERMAL CONTACT CONDUCTANCE; THEORETICAL CONSIDERATIONS , 1974 .

[8]  C. Madhusudana.  Thermal Contact Conductance , 1996 .

[9]  Franz G. Rammerstorfer,et al.  Some simple models for micromechanical investigations of fiber arrangement effects in MMCs , 1993 .