Diamond Heat Spreaders Will Not Replace Liquid Cooling

With the rapid iteration of large AI models and high-performance computing, chip power consumption and power density keep climbing, and thermal management has long been one of the core bottlenecks restricting computing performance. Against this backdrop, diamond thermal technology has become an industry hotspot thanks to its thermal conductivity far outperforming traditional metals. Along with the hype comes the claim that "diamond cooling will replace liquid cooling." Yet returning to the fundamental logic of thermal design reveals that the two sit at completely different layers of the heat dissipation chain. They are by no means an either-or competitive alternative, but an upstream-downstream collaborative pair.

 

(Diamond's chip-level thermal diffusion
The industry-standard diamond packaging heat dissipation schematic clearly labels the chip hot spots, CVD diamond diffusion layer, and thermal flow paths, visually illustrating the core function of "rapidly spreading extremely small-area hot spots.")

 

Diamond Thermal Solutions: Fixing "Thermal Congestion" Inside the Chip

To grasp the role of diamond heat spreaders, we first need to understand the heat profile of computing chips: the bare die of a high-power chip is extremely small, with hundreds of watts concentrated in an area of just a few square centimeters, and local hotspots shrink to the micrometer scale, creating extremely high heat flux.

 

In conventional cooling schemes, common heat sink materials like copper and aluminum have limited lateral spreading capacity. Heat easily gets trapped inside the chip and fails to conduct out smoothly, forming a package-level thermal bottleneck - and this is exactly where diamond delivers its core value. Diamond has a room-temperature thermal conductivity several times that of copper, making it one of the most thermally conductive materials known. Its core function is first-stage heat spreading at the chip level: it rapidly diffuses the concentrated hotspots on the tiny die across a much larger surface, so that heat can be smoothly passed on to downstream thermal structures.

 

In short, diamond solves the problem of "how heat gets out of the chip die." It operates inside the chip package, and does not take on the job of ultimately expelling heat from the entire device.

 

Liquid Cooling: The "Main Artery" for System-Level Heat Rejection

Unlike the chip-level positioning of diamond, liquid cooling is a system-level terminal cooling solution, sitting in the second half of the full thermal chain.

 

Once heat spreads out of the chip and reaches the package surface, liquid cooling continuously carries it away from the equipment via cold plate contact and coolant circulation, then releases it to the environment through an external heat exchanger. In high-density computing scenarios where a single chip draws hundreds of watts and a full system consumes kilowatts, air cooling has hit its physical heat exchange limit. Liquid cooling, with its higher heat transfer efficiency and more stable temperature control, has become the dominant optimal solution for full-system thermal management.

 

It addresses the problem of "how heat gets discharged from the equipment." It is the terminal "outlet" of the entire cooling system. No matter what material handles heat spreading at the chip end, system-level cooling is always required to remove the heat completely.

 

 

Not Substitution, but Synergy: Cooling Is a System Engineering Discipline

Thermal management is never a performance contest of a single material, but a complete chain from die to system. The bottleneck at any link defines the overall cooling limit.

 

A simple analogy: a diamond heat spreader is like the local road network in a neighborhood, which quickly channels traffic from every home onto the main road; liquid cooling is the city's outer ring expressway, which carries the accumulated traffic straight out of the city. Without local roads to clear traffic, cars would back up inside the neighborhood; without the expressway to handle throughput, the main road would have nowhere to send its load.

 

In real-world industrial deployment, diamond heat spreaders are precisely used in tandem with liquid cooling systems: diamond first rapidly spreads heat from chip hotspots to prevent local overheating and device failure; liquid cooling then picks up the diffused heat across the larger surface and efficiently exhausts it from the system. The stronger diamond's spreading capability becomes, the more heat exchange capacity the downstream liquid cooling system needs to handle the load. The two enable each other in an upgrade relationship, rather than competing to replace one another.

 

Beyond the "Replacement Myth": The Real Iteration Logic of Cooling Technology

The misconception that "diamond will replace liquid cooling" essentially confuses the performance advantage of a single material with a complete system-level solution.

 

For one thing, diamond is costly to manufacture and only practical for use in the tiny core region of the chip - it can never cover the full thermal path from die to system. For another, thermal system bottlenecks shift dynamically: once the chip-level spreading bottleneck is resolved by diamond, the system-level heat rejection bottleneck becomes even more pronounced, and demand for higher-performance liquid cooling will only grow, not vanish.

(AI computing power data center liquid cooling cluster)

 

Conclusion

Cooling upgrades for high-performance computing are never a linear narrative of "new materials overturning old solutions," but the co-evolution of technologies at every layer. Diamond thermal technology is a key breakthrough in chip package thermal management, while liquid cooling remains the core pillar of system-level cooling architecture. Each plays its own part and complements the other - and that is the mainstream path forward for high-density thermal design.