Optimization of Effective Thermal Conductivity of Thermal Interface Materials Based on the Genetic Algorithm-Driven Random Thermal Network Model

Abstract

Polymer-based thermal interface materials (TIMs) are indispensable for reducing the thermal contact resistance of high-power electronic devices. Owing to the low thermal conductivity of polymers, adding multiscale dispersed particles with high thermal conductivity is a common approach to enhance the effective thermal conductivity. However, optimizing multiscale particle matching, including particle size distribution and volume fraction, for improving the effective thermal conductivity has not been achieved. In this study, three kinds of filler-loaded samples were prepared, and the effective thermal conductivity and average particle size of the samples were tested. The finite element model (FEM) and the random thermal network model (RTNM) were applied to predict the effective thermal conductivity of TIMs. Compared with the FEM, the RTNM achieves higher accuracy with an error less than 5% and higher computational efficiency in predicting the effective thermal conductivity of TIMs. Combining the abovementioned advantages, we designed a set of procedures for an RTNM driven by the genetic algorithm (GA). The procedure can find multiscale particle-matching ways to achieve the maximum effective thermal conductivity under a given filler load. The results show that the samples with 40 vol %, 50 vol %, and 60 vol % filler loading have similar particle size distribution and volume fractions when the effective thermal conductivity reaches the highest. It should be emphasized that the optimized effective thermal conductivity can be improved obviously with the increase in the volume fraction of the filler loading. The high efficiency and accuracy of the procedure show great potential for the future design of high-efficiency TIMs.

Numerical Simulation on the Optimization of the Anisotropic Thermal Conductivity of Hexagonal Boron Nitride/Nanofiber Composite Films

“…So, the single h-BN-filled geometric model seems inappropriate for studying the synergistic impact on the overall thermal conductivity . Additionally, some studies have indicated that the effective thermal conductivity of composites closely correlates to the properties of interface because the generated interface thermal resistance affects heat transfer, − but the interface components are usually absent for many built finite element models. − Therefore, the randomly generated geometric model needs to be further developed, and a comprehensive analysis of the role of the variable is highly desired.…”

Graphene/Polyolefin Elastomer Films as Thermal Interface Materials with High Thermal Conductivity, Flexibility, and Good Adhesion

“…With the rapid development of microelectronic techniques, chips are becoming smaller and more integrated, and computing speed is becoming faster. − Consequently, a significant amount of heat generates in chips with a small volume, causing the reduction of operating stability and service life. , Heat dissipation has become a critical issue for electronic packing materials. , This problem is usually addressed by the bonding of thermal interface materials (TIMs) between the chips and the heat spreader to transfer the heat generated from the operation of chips, thereby ensuring proper operation of chips. , Polymer materials have been widely applied in the area of TIMs due to their good mechanical properties, electric insulation, convenient durability, and easy processability. − However, the thermal conductivities of polymers are not good (about 0.2–0.5 W m K –1 ). To improve the heat conduction performance, thermally conductive fillers are incorporated into the polymer matrix, including BN, AlN, Al 2 O 3 , CNT, and GNP, in which the thermal resistance between fillers is considerable that decreasing the heat conduction efficiency seriously.…”

Stretchable Thermal Interface Materials by Tailoring the Chain Relaxation at the Filler/Polymer Interface

“…For practical applications of TIMs, thermal conductivity is the most intuitive property to exhibit the ability to removal of heat generation by chips. Owing to the low cost and flexibility, polymer-based composites consisting of polymer matrix and thermally conductive fillers have been widely used as TIMs. , With the development of higher power density and larger IC packages, thermal interface materials will be subjected to mechanical stresses strains in the package, resulting in loss of performance . Therefore, thermal interface materials must not only meet the thermal objective but also be stretchable to maintain their performance through the life of the package without significant degradation .…”