Micro-channel heatsink brazing for low cost manufacturing
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Solution Overview
Problem
Conventional cooling methods for high heat flux power semiconductor devices face challenges in achieving uniform temperature distribution and are costly due to complex manufacturing processes and high costs associated with micro-channel designs.
Innovation Solution
A channel-type heat sink structure comprising a ceramic layer, a metal layer, a channel layer, and a manifold layer, bonded together with a plenum housing, which allows for efficient coolant distribution and assembly without the need for soldering, using a high-temperature brazing process to maintain channel integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional micro-channel designs are used with soldering and complex backside structures, then cooling performance is improved, but manufacturing complexity and cost increase significantly
Solution Approach 1:
The heat sink is divided into separate functional layers (base plate, manifold layer, channel layer) that can be manufactured independently and then assembled. This segmentation allows each layer to be optimized and manufactured separately using appropriate processes, reducing overall manufacturing complexity while maintaining cooling performance.
Solution Approach 2:
The invention transitions from conventional 2D planar cooling channels to a 3D multi-layer vertical structure. Channels extend through multiple layers (base plate, manifold, channel layer) creating a three-dimensional cooling architecture that improves heat dissipation while simplifying manufacturing through layer-by-layer construction.
2Power
If complex backside micro-channel structures are employed, then heat flux handling capability is improved, but manufacturing cost and difficulty increase
Solution Approach 1:
The complex micro-channel structure is segmented into standardized layers (channel layer with embedded channels, manifold layer, base plate) that can be manufactured using conventional semiconductor fabrication processes. This segmentation transforms an intractable monolithic structure into manageable, repeatable manufacturing steps.
Solution Approach 2:
The invention changes the manufacturing parameters from conventional metalworking to semiconductor-compatible processes (photolithography, etching, deposition). This parameter change enables precise control of channel dimensions and geometry while using standard, cost-effective manufacturing equipment.
3Strength
If soldering processes are used to assemble substrate to heat sink, then structural integrity is improved, but channel feature integrity is compromised
Solution Approach 1:
A dedicated channel layer acts as an intermediary between the base plate and manifold, protecting the delicate coolant channels from damage during assembly. This intermediate layer shields the channels from mechanical stress and thermal damage that would otherwise occur during soldering operations.
Solution Approach 2:
The invention replaces mechanical soldering processes with a layered assembly approach where layers are bonded together without requiring high-temperature soldering that would damage the channels. This substitution eliminates the harmful thermal and mechanical effects of soldering on the channel structure.
4Ease of manufacture
If natural and forced air cooling schemes are used, then simplicity is maintained, but heat flux handling capability is limited to about 1 W/cm2
Solution Approach 1:
The invention transitions from gas-based air cooling to liquid-based cooling by embedding coolant channels within the heat sink structure. Liquid coolant flowing through these channels provides superior heat transfer coefficients, enabling heat flux handling capabilities exceeding 100 W/cm2 while maintaining a relatively simple integrated structure.
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 provides effective thermal management with improved heat flux handling and reduced manufacturing complexity and costs, enabling efficient cooling of high heat flux power devices while maintaining channel feature integrity.
Implementation Method 1
bonding a first metal layer to one side of the first ceramic substrate; bonding a first side of a first channel layer to an opposite side of the first ceramic substrate; and bonding a first manifold layer to a second side of the first channel layer
Implementation Method 2
a ceramic layer comprising a first planar surface and a second planar surface substantially parallel to the first planar surface; a metal layer bonded to the first planar surface
Implementation Method 3
channel layer bonded to the second planar surface; manifold layer bonded to a surface of the channel layer opposite the second planar surface
Data Source
AI summary
A cooling device includes a ceramic substrate with a metal layer bonded to an outer planar surface. The cooling device also includes a channel layer bonded to an opposite side of the ceramic substrate and a manifold layer bonded to an outer surface of the channel layer. The substrate layers are bonded together using a high temperature process such as brazing to form a single substrate assembly. A plenum housing is bonded to the single substrate assembly via a low temperature bonding process such as adhesive bonding and is configured to provide extended manifold layer inlet and outlet ports.