Multidimensional Heat‐Path Engineering in Thermal Interface Materials for High‐Performance Electronics

ABSTRACT

The rapid expansion of artificial intelligence, high‐performance computing, and chiplet‐based electronic platforms is intensifying package‐level thermal bottlenecks by increasing power density and hotspot severity. Polymer‐composite thermal interface materials (TIMs) offer scalable fabrication and cost‐effective manufacturing, yet gains in bulk or effective thermal conductivity often do not translate into proportionate improvements in bonded thermal performance. This mismatch arises because effective heat transfer in real joints is governed not by conductivity alone, but by three coupled design domains: (i) heat transport within the composite, (ii) bonded interfacial contact and bondline behavior, and (iii) processing‐defined pathway architecture. In practical TIM layers, heat must travel through internal filler networks, where transport is governed by network organization, filler‐matrix coupling, and multiscale connectivity, before crossing rough external interfaces shaped by wetting, compliance, pressure, rheology, and stability. This review reorganizes the polymer‐composite TIM literature through multidimensional heat‐path engineering, a framework that integrates these three design domains rather than cataloging filler families or conductivity records alone. On this basis, design principles are synthesized for coordinating internal transport, interfacial contact and bondline evolution, and architected pathway accessibility, while metrology, degradation, and reliability are highlighted as essential considerations for translating transport gains into effective bonded performance under realistic service constraints.