The next generation of thermal interface materials (TIMs) is entering the scene, offering the opportunity for a quantum leap in thermal efficiency, reliability, and market growth. IDTechEx's research in the report "Thermal Management for Advanced Semiconductor Packaging 2026-2036: Technologies, Markets, and Opportunities" reveals the business opportunities and technical innovations of next-generation TIMs for advanced semiconductor packaging.
TIM1 → TIM1.5 Evolution: a revolutionary change
Innovations in TIM architecture are transforming heat transfer. The advanced semiconductor packaging industry is moving from the classic two-layer system (TIM1 + TIM2) to a unified TIM1.5 layer, designed to reduce the thermal path length and eliminate interfaces—essential for stacked chip assemblies.
Liquid metal alloys (phase-change metal alloy TIMs), solid at room temperature but molten during operation, offer ultra-low interfacial resistance and high conductivity, making them well-suited for TIM1.5 applications.
Indium-based TIMs offer thermal conductivities as low as ~86 W/m·K, with melting points (~157 °C) ideal for bonding, minimal gap formation, and excellent mechanical conformability.
The graphene-aligned pads developed by Hitachi Chemical offer through-plane conductivity exceeding 20 W/m·K under moderate pressures (~20 psi), a significant improvement over polymer greases.
Key performance metrics
TIM benchmark comparison. Source: IDTechEx
Key features:
Liquid metal/indium sandwich TIMs offer a contact resistance as low as 0.036 cm²·K/W at 50 psi, outperforming high-end thermal pads and withstanding ≥200 temperature cycles with minimal performance loss.
The pure indium sheet (approximately 0.05 mm thick) achieves around 84 W/m·K, remains flexible from cryogenic to high-temperature ranges, and continues to function between -273 °C and ~155 °C.
Graphene-aligned TIMs using vertically oriented fillers offer >20 W/m·K across their entire thickness, but maintaining low contact resistance requires sufficient pressure (>20 psi) and material conformity.
Graphene compounds can increase the thermal conductivity of conventional greases by a factor of ~17×, even with a modest filler load (5-10% by volume), with an interface resistance (~3-4 mm²·K/W) at 330 K that rivals commercial TIMs.
Why TIM1.5 is a strategic differentiator
TIM1.5 is not just a material; it's a performance philosophy:
It dramatically reduces interfacial thermal resistance by eliminating transitions between layers.
This enables critical chip-to-spreader efficiency in high-density multi-chip modules.
It offers greater unit value; early adopters report a price 3 to 5 times higher than conventional TIMs, allowing for increased margins. (Industry estimate)
Combined with increasing thermal loads driven by high-bandwidth memory, AI accelerators, and stacked chips, the TIM (TIM1 + TIM1.5) market is projected to reach US$500 million by 2036, representing a strong business opportunity. (IDTechEx)
Engineering Considerations and Market Enablers
: Contact Quality: TIMs with high k-values perform worse if the interface contact is poor; pressure, surface finish, and the absence of gaps are critical. Optimizing the contact area and mechanical conformity dramatically reduces Rₙ.
Reliability: Advanced TIMs, such as LM sandwiches, withstand hundreds of thermal cycles and operating hours with sustained performance.
Regulatory Compliance: RoHS regulations and material certification (e.g., UL 94 listing) may limit the adoption of certain metal-based TIMs, such as indium-Ga alloys, which face regulatory scrutiny in specific regions.
Conclusion: The TIM frontier
Advanced TIMs, especially TIM1.5, are not incremental improvements, but fundamental enablers of 3D semiconductor packaging and ultra-high-performance chips. However, despite TIM1.5's widespread use in advanced semiconductor packaging, such as Nvidia's B200, IDTechEx has found that technical challenges remain and the industry is still transitioning from capped TIM1+TIM2 designs to capless TIM1.5 designs.
More information can be found in the IDTechEx report, "Thermal Management for Advanced Semiconductor Packaging 2026-2036: Technologies, Markets and Opportunities".
