An Integrated Cooling Solution for Hot Chips

Meeting the Thermal Challenge of High-Performance Compute ICs

The semiconductor industry is undergoing a major transformation, driven by the demand of artificial intelligence (AI) and high-performance computing (HPC). As processor chips become more powerful, they generate higher power densities, making thermal management a critical challenge -especially for data centers. These processor chips are combined onto 2.5 – 3.5 D modules which are growing in footprint and total power (Figure 1). To meet this need, Adeia has developed a groundbreaking Integrated Cooling Solution (ICS) that dramatically improves heat dissipation while maintaining system reliability and energy efficiency.

The Need for Advanced Thermal Solutions

As semiconductor technologies advance, smaller feature sizes and higher transistor densities result in more heat being concentrated in tighter spaces. Without effective cooling, this excess heat can degrade performance, cause computational errors, and shorten device lifespan. Traditional cooling approaches, such as air cooling and standard Direct Liquid Cooling (DLC) using cold plates face limitations. A significant source of inefficiency is the thermal interface material (TIM), which introduces resistance to heat transfer.

Rethinking Liquid Cooling: The Integrated Cooling Solution (ICS)

Ron Zhang, Senior Director of Advanced Packaging and Thermal Solutions at Adeia, shared the performance of ICS in his paper, “Revolutionary Thermal Solutions for Hot Chips” at the IEEE ITHERM Conference held in Dallas, TX, on May 27-30, 2025. ¹

Adeia’s ICS addresses these challenges by eliminating the TIM layer and directly bonding a silicon cold plate to the hot chip (Figure 2).

This novel approach provides several key advantages:

• Significant Reduction in Thermal Resistance: By removing the TIM layer, conductive thermal resistance is minimized, enhancing heat dissipation.
• Enhanced Thermal Performance: Experimental data shows a 70% reduction in total thermal resistance for power densities ranging from 1.5 W/mm² to 2 W/mm².
• Lower Pressure Drop: Unlike conventional microchannel-based cooling, ICS achieves lower pressure drops, comparable to traditional copper cold plates.
• Leak-Free Operation: The direct bonding technique eliminates the risk of coolant leakage—a common concern with embedded microchannel cooling systems.

Optimizing Cold Plate Design for Maximum Efficiency

Adeia researchers investigated multiple cold plate geometries to strike an optimal balance between heat dissipation and pressure drop.

Key Design Considerations:

• Post Structures vs. Microchannels:
  • Various configurations, including square and rectangular post arrays, were tested for thermal efficiency. Staggered post arrangements reduced peak temperatures by 4°C, while aligned rectangular posts improved pressure drop performance by a factor of four.
  • A full-length microchannel design demonstrated a 9x improvement in pressure drop compared to staggered posts.
• Channel Geometry:
  • Transitioning the channels from trapezoidal to triangular cross-sectional shapes enhanced the thermal performance.
  • For benchmarking, Adeia scaled their ICS cold plate to match the dimensions used in the classic Tuckerman and Pease microchannel model. Results showed a 14% reduction in thermal resistance at lower flow rates, demonstrating ICS’s superior efficiency.

Experimental Validation: ICS vs. Conventional Cold Plates

To validate performance, Adeia conducted extensive thermal testing comparing ICS silicon-based microchannel cold plates against commercially available metal-based cold plates. The results are encouraging.

• ICS outperformed gaming and HPC cold plates, achieving up to 80 % lower thermal resistance.
• At a flow rate of 0.3 GPM, ICS enabled a 3x increase in power density while maintaining a junction temperature of ~100°C matching conventional solutions.
• Computational Fluid Dynamics (CFD) simulations closely aligned with experimental data (within a 5% margin), confirming the predictability of their simulation to our fabrication and test.

Future Directions: Tackling Pressure Drop and Hot Spots

While ICS already demonstrates industry-leading thermal performance in reticle size test structures, further research is underway to enhance its capabilities:

• Optimizing Pressure Drop: Fine-tuning the balance between heat transfer and fluid dynamics is essential for improving overall system efficiency.
• Managing Hot Spots: Adaptive cooling strategies are being explored to target localized high-temperature regions on next-generation chips.

Leading the Next Era of Chip Cooling

Adeia’s Integrated Cooling Solution represents a paradigm shift in semiconductor thermal management. By eliminating the TIM layer and leveraging advanced silicon bonding techniques, ICS delivers improved thermal efficiency -reducing chip temperatures, increasing reliability to enabling higher computational chipsets for AI-centric data centers. As power densities continue to escalate, cutting-edge cooling technologies like ICS will be central to advancing the future of high-performance computing.

References

1. Zhang et al, “Revolutionary Cooling Solution for Hot Chips”, iTherm 2025, May 2025.
2. D.B. Tuckerman and R.F.W. Pease, IEEE Electronic Device Letters, EDL-2, No. 5, 1981.