Designs for low-thermal-resistance thermal interface materials: Oriented high-conductivity networks, ultra-thin bond lines thickness and contact-resistance minimization

As integrated-circuit dimensions approach the nanometer scale, chip power density rises and heat flux intensifies, which limits computational speed, operating stability and device lifetime. Thermal interface materials (TIMs) fill micro- and nano-scale gaps between chips and heat sinks to promote interfacial heat transfer and lower contact thermal resistance ( R c ), thereby improving overall heat dissipation efficiency. We systematically summarize recent progress in high-performance TIMs and clarify their essential role in addressing thermal-management challenges driven by rising power densities in modern electronic systems. From a materials-design perspective, we summarize state-of-the-art fabrication strategies and categorize them according to performance-oriented design routes. First, electric or magnetic field alignment, hot pressing, templating and chemical vapor deposition (CVD) organize boron nitride (BN), graphene and carbon nanotubes (CNTs) into ordered architectures. These architectures form efficient three-dimensional (3D) phonon transport pathways and substantially increase the thermal conductivity ( κ ). Second, under assembly pressure, thermal greases spread and wet the contacting surfaces, confining the bond line thickness ( BLT ) to the micrometer scale. This confinement significantly reduces the bulk thermal resistance ( R b ) and supports efficient heat transfer. Third, liquid metals (LMs) and phase-change materials (PCMs) convert discrete point contacts into continuous areal contacts. This action expels interfacial air, accommodates surface roughness, and markedly lowers the contact thermal resistance. Looking ahead, progress will depend on coordinating the optimization of high κ , low interfacial thermal resistance (ITR), mechanical compliance, dielectric insulation and manufacturing compatibility. For emerging applications in fifth-generation (5 G) mobile communication systems, high-power chips and flexible electronics, TIMs with adaptive interfacial behavior, reusability and multi-physics coupling are expected to guide the next stage of material and device development. Scheme. Mechanisms and fabrication methodologies for low- R t TIMs