Rheological Study of Micro Particle Laden Polymeric Thermal Interface Materials: Part 2 — Modeling

Abstract

Currently there are no models to predict the thickness or the bondline thickness (BLT) of particle laden polymeric thermal interface materials (TIM) for parameters such as particle volume fraction and pressure. TIMs are used to reduce the thermal resistance. Typically this is achieved by increasing the thermal conductivity of these TIMs by increasing the particle volume fraction, however increasing the particle volume fraction also increases the BLT. Therefore, increasing the particle volume fraction may lead to an increase in the thermal resistance after certain volume fraction. This paper introduces a model for the prediction of the BLT of these particle laden TIMs. Currently thermal conductivity is the only metric for differentiating one TIM formulation from another. The model developed in this paper introduces another metric: the yield stress of these TIMs. Thermal conductivity and the yield stress together constitute the complete set of material parameters needed to define the thermal performance of particle laden TIMs.

Mixing, rheology, and stability of highly filled thermal pastes

“…Most reported studies [15][16][17][18][19][20][21] have been carried out on highly filled systems of a very different nature, such as phase-change materials [15], thermal gels [16], and other polymer-based systems [17][18][19][20][21]. In this paper, we discuss what is relevant to understanding the rheology of thermal pastes.…”

“…Similarly, only a few studies [15][16][17][18][19][20][21] exist on the rheology of thermal pastes, although their flow behavior is critical in attaining the narrow gap thickness required to reduce the thermal resistance between a computer chip and a cooled surface, or ''hat.'' Most reported studies [15][16][17][18][19][20][21] have been carried out on highly filled systems of a very different nature, such as phase-change materials [15], thermal gels [16], and other polymer-based systems [17][18][19][20][21].…”

Fundamentals of the Squeeze-Flow Between a Heat Sink and a Flip-Chip

“…However, as reported by Prasher et AI. [1] in Table 2, the particle volume fraction strongly influences the physical properties of the Herschel-Bulkley material and, consequently, the behaviour of the Non-Newtonian fluid. This is illustrated in Fig.…”

“…This problem has been the subject of few investigations in the past. Studies were conducted both experimentally and computationally for Newtonian as well as Non-Newtonian fluids under different flow conditions [1][2][3][4][5][6][7]. The problem of squeeze-flow between rigid plates fmds an interesting application in the assembly of electronic components.…”