Thermal interface materials (TIM) continue to function as one of the most essential elements in the electronics thermal management ecosystem. As their role expands to more applications, newer challenges are emerging, some of which are: lower bondline (<50um) thicknesses, larger bondline (>4mm) gaps, lower clamping pressure (<10psi), ability to conform to surfaces (profile-matching) in case of preform TIMs, compatibility for surface mount assembly and reflow, higher thermal conductivity and spreading features, reusability and shape recovery when interface pressure is removed, application in flexible hybrid electronics (FHE), etc.
Efficiently engineered TIM stacks that are customizable offer many advantages such as high thermal conductivity and excellent contact resistance (low thermal impedance) at low pressures. Furthermore, when such stacks are incorporated, very low stress relaxation and nearly zero compression set results in no degradation of contact pressure, i.e., the interfacial surfaces remain in contact with each other as when first mated. The mechanical stress coupling between the interface and the component is thus greatly reduced and in some cases, benefits of some vibration damping may also be realized.
In this paper, we present the results of evaluating some newer high performance TIMs in demanding applications such as automotive power electronics, FPGAs, consumer electronics, network processors and others. The test cases include SOT-223 package, lidless BGA package, fan-less edge computing PC and Open Compute server. The evaluation of thermal performances based on CFD simulation clearly show that an efficiently engineered TIM can drop junction / case / heatsink temperatures by 10’s of degrees in high power dissipating components. This has a direct impact on products’ performance, i.e., increased duty cycles, longer operating life, uprating of memories, cooling costs in data center applications, etc., to mention a few.