3D Two-Phase Microfluidic Cooling With Wicking Boiling Surfaces
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Solution Overview
Problem
Computing devices generate significant heat, which can damage components and requires effective cooling systems. Existing cooling systems face challenges in managing varying thermal demands across different computing applications.
Innovation Solution
A processor design incorporating a wicking heat spreader with a microfluidic volume between two dies, featuring through-silicon vias (TSVs) for electrical connection and boiling enhancement surface features to promote heat transfer and vapor bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling systems are used, then device simplicity is maintained, but heat transfer efficiency is insufficient
Solution Approach 1:
The patent employs a wicking heat spreader with porous structure containing capillary channels. The porous material enables passive fluid transport through capillary action without pumps, while providing large surface area for heat transfer. The capillary channels draw cooling fluid upward against gravity, enabling efficient heat removal from the processor die.
Solution Approach 2:
The patent utilizes two-phase cooling where the cooling fluid undergoes phase transition from liquid to vapor at the heating surface. Vapor bubbles form at nucleation sites on the heated surface, absorbing latent heat of vaporization. The vapor rises and condenses elsewhere, releasing heat, completing the thermodynamic cycle and providing high heat transfer efficiency.
2Temperature
If standard heat spreader surfaces are used, then manufacturing simplicity is maintained, but heat transfer and vapor bubble formation are insufficient
Solution Approach 1:
The patent introduces localized surface features called nucleation sites on the heat spreader surface. These are not uniform across the entire surface but are strategically positioned areas with specific micro-structures (such as pits, protrusions, or controlled roughness) that promote vapor bubble formation. This local modification enhances heat transfer at critical locations without requiring complete surface restructuring.
Solution Approach 2:
The nucleation sites are pre-formed on the heat spreader surface during manufacturing, preparing the surface in advance to facilitate vapor bubble formation. This preliminary structuring ensures that when the two-phase cooling system operates, vapor bubbles can immediately form at these predetermined locations, enhancing heat transfer efficiency from the start of operation.
3Temperature
If single-phase cooling is used, then system simplicity is maintained, but thermal management capacity is insufficient for high heat loads
Solution Approach 1:
The patent implements two-phase cooling where the working fluid alternates between liquid and vapor phases. Liquid coolant absorbs heat from the processor die, undergoes phase change to vapor at the heating surface (absorbing latent heat), vapor rises and condenses in a heat exchanger (releasing latent heat), and returns as liquid to repeat the cycle. This phase transition mechanism provides superior heat transfer capacity compared to single-phase cooling.
Solution Approach 2:
The two-phase cooling system is designed to be self-regulating. The phase change process automatically adjusts to heat load variations - higher heat loads produce more vapor, which increases the cooling effect. The capillary wicking structure self-adjusts fluid flow based on heat demand without external control, providing adaptive thermal management.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances heat transfer efficiency by utilizing a wicking heat spreader and boiling enhancement surface features, effectively managing thermal energy and preventing component damage.
Implementation Method 1
a wicking heat spreader positioned in the microfluidic volume
Implementation Method 2
a boiling enhancement surface feature positioned on at least one surface of the wicking heat spreader
Implementation Method 3
utilizing a wicking heat spreader and boiling enhancement surface features, effectively managing thermal energy
Data Source
AI summary
A processor includes a first die, a second die connected to the first die with a microfluidic volume positioned between the first die and the second die, a wicking heat spreader positioned in the microfluidic volume; and a boiling enhancement surface feature positioned on at least one surface of the wicking heat spreader.