Micro-channel Cooling Bond Layer for Power Electronics Thermal Management
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Solution Overview
Problem
Power electronics devices, such as IGBTs and transistors, face increasing operating temperatures due to advances in battery technology and electronics packaging density, necessitating more effective cooling solutions beyond traditional heat sinks.
Innovation Solution
A cooling bond layer with a metal matrix and micro-channels is introduced between semiconductor devices and substrates, allowing for the flow of a cooling fluid to remove heat, with the micro-channels optionally having a constant or graded diameter and potentially formed using a reflow soldering process with a sacrificial template.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional heat sinks are used for cooling power electronics devices, then cooling function is provided, but the size of cooling structures must increase to handle higher operating temperatures
Solution Approach 1:
The cooling bond layer is segmented into a metal matrix containing multiple micro-channels, allowing distributed heat removal throughout the bonding layer rather than relying on a single large heat sink. This segmentation enables efficient heat transfer at the source while maintaining compact overall dimensions.
Solution Approach 2:
The invention transitions from conventional external heat sink cooling to internal micro-channel cooling within the bond layer itself. By embedding cooling channels in the third dimension within the bonding structure, heat removal efficiency is dramatically improved without increasing the horizontal footprint or overall assembly size.
2Temperature
If cooling structures are enlarged to handle higher temperatures, then cooling capacity increases, but device packaging density decreases
Solution Approach 1:
The cooling function is merged with the bonding structure by integrating micro-channels directly into the bond layer. This combination eliminates the need for separate external heat sinks, maintaining high packaging density while providing adequate cooling capacity through the distributed micro-channel network.
Solution Approach 2:
The metal matrix with micro-channels creates a controlled porous structure that enables efficient heat transfer. The distributed void spaces (micro-channels) throughout the bonding layer provide multiple heat removal pathways, achieving high cooling capacity without increasing overall volume or reducing packaging density.
3Temperature
If micro-channels are added to the bond layer, then heat removal efficiency improves, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process utilizes parameter changes, specifically temperature-dependent phase transitions of solder material, to form the metal matrix around the template. By controlling melting and solidification temperatures, the complex micro-channel structure is created through a relatively simple reflow process rather than requiring complex machining or additive manufacturing.
Solution Approach 2:
A removable template serves as an intermediary element during manufacturing. The template defines the micro-channel geometry and is temporarily held in place during solder reflow, then removed afterward to reveal the cooled bond layer structure. This intermediary approach simplifies the manufacturing process by avoiding direct formation of micro-channels through complex processes.
4Ease of manufacture
If template-based reflow soldering is used to form micro-channels, then manufacturing is simplified, but additional process steps are required
Solution Approach 1:
The template is positioned and prepared in advance before the reflow soldering process. This preliminary action establishes the micro-channel geometry beforehand, allowing the subsequent solder reflow to automatically form the metal matrix around the pre-positioned template without requiring real-time control or complex in-process adjustments.
Solution Approach 2:
The template is discarded after serving its purpose during manufacturing. After the metal matrix forms around the template during reflow soldering, the template is removed (discarded) to reveal the functional micro-channel structure. The template is a sacrificial element that is consumed in the manufacturing process to enable the final product formation.
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 enhances heat removal from power electronics devices, potentially reducing the size of cooling structures needed and improving thermal management without requiring additional heat sinks, thus addressing the challenge of rising operating temperatures.
Implementation Method 1
a cooling fluid to flow through and remove heat from the cooling bond layer
Implementation Method 2
heat transferred to the cooling bond layer from the semiconductor device
Implementation Method 3
The metal matrix of the cooling bond layer may be formed by reflow soldering in which a liquid soldering material flows and solidifies around a template
Data Source
AI summary
A cooling bond layer for a power electronics assembly is provided. The cooling bond layer includes a first end, a second end spaced apart from the first end, a metal matrix extending between the first end and the second end, and a plurality of micro-channels extending through the metal matrix from the first end to the second end. The plurality of micro-channels are configured for a cooling fluid to flow through and remove heat from the cooling bond layer. In some embodiments, the plurality of micro-channels are cylindrical shaped micro-channels. In such embodiments, the plurality of micro-channels may have a generally constant average inner diameter along a thickness of the cooling bond layer. In the alternative, the plurality of micro-channels may have a graded average inner diameter along a thickness of the cooling bond layer. In other embodiments, the plurality of micro-channels may have a wire mesh layered structure.