3D Microfluidic Wicking Heat Spreader for Boiling Dryout Control
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Solution Overview
Problem
Computing devices generate significant heat, requiring effective cooling systems to prevent damage, but conventional heat spreaders have limited surface area and efficiency in heat transfer due to vapor formation, leading to increased temperatures and potential dryout in immersion cooling systems.
Innovation Solution
The implementation of a wicking heat spreader with microfluidic volumes and boiling enhancement surface features, such as through-silicon vias (TSVs) and boiling enhancement coatings, enhances heat transfer by increasing surface area and promoting vapor bubble formation and release, improving thermal management in stacked-die processors and immersion cooling systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional heat spreaders are used, then device simplicity is maintained, but heat transfer efficiency is limited due to restricted surface area and vapor formation
Solution Approach 1:
The heat spreader surface is segmented into multiple functional zones including wicking structures with capillary channels, boiling enhancement regions with nucleation sites, and microfluidic volumes. This segmentation increases the effective heat transfer surface area and enables different heat transfer mechanisms to operate simultaneously, resolving the contradiction between heat transfer efficiency and structural simplicity.
Solution Approach 2:
Porous wicking materials are integrated into the heat spreader structure to provide capillary action for fluid transport. The porous structure increases surface area for heat transfer while maintaining a relatively simple overall device geometry, thus improving heat transfer efficiency without proportionally increasing device complexity.
2Productivity
If heat spreader surface area is increased, then heat transfer capacity is improved, but device volume and complexity increase
Solution Approach 1:
The heat spreader utilizes three-dimensional microfluidic volumes and vertical wicking structures to increase heat transfer surface area in the vertical dimension rather than expanding horizontally. This allows significant heat transfer capacity improvement while maintaining a compact device footprint, resolving the contradiction between heat transfer capacity and device volume.
Solution Approach 2:
Microfluidic channels and wicking structures are nested within the heat spreader body, creating internal heat transfer surfaces that do not increase the external dimensions of the device. This nested configuration enables high heat transfer capacity within a compact volume.
3Productivity
If vapor bubble formation is suppressed, then heat spreader surface remains stable, but heat transfer efficiency decreases due to reduced phase change cooling
Solution Approach 1:
The heat spreader surface is designed with local variations in properties: hydrophilic wicking regions for liquid transport, hydrophobic regions for vapor release, and nucleation sites for controlled bubble formation. This local differentiation allows vapor bubbles to form in specific controlled locations rather than across the entire surface, maintaining surface stability while enabling efficient phase change heat transfer.
Solution Approach 2:
The patent converts the potentially harmful effect of random vapor bubble formation (which can cause surface instability and dryout) into a beneficial controlled process. By providing specific nucleation sites and using surface energy differentiation, vapor formation is directed to specific regions where it enhances heat transfer without compromising overall surface stability.
4Productivity
If wicking structures are added to increase surface area, then heat transfer is improved, but manufacturing complexity increases
Solution Approach 1:
The wicking structures are fabricated by modifying physical and chemical parameters of the heat spreader material during manufacturing, such as creating porous structures through controlled etching, sintering, or phase separation. These parameter changes enable wicking functionality without requiring assembly of separate components, thus improving heat transfer rate while maintaining ease of manufacture.
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
This solution effectively increases heat transfer rates and thermal management capacity by utilizing wicking heat spreaders with enhanced surface features, allowing for efficient vapor bubble formation and release, thereby maintaining safe component temperatures and preventing dryout in immersion cooling systems.
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
promoting vapor bubble formation and release
Implementation Method 4
a first die, a second die connected to the first die with a microfluidic volume positioned between the first die and the second die
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.