Laminated Heat Radiation Member for Thermal Cycle Durability
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Solution Overview
Problem
Existing heat radiation members for semiconductor devices face challenges in maintaining thermal conductivity and durability under repeated thermal stress due to heat cycles, with issues such as bonding failure and thermal resistance increase.
Innovation Solution
A laminated structure comprising a carbon material with specific gas permeability and bending strength, bonded with metal materials like aluminum or copper alloys, which are separated and bonded through solidification or brazing, ensuring a high area ratio of carbon material coverage and effective thermal conductivity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a porous sintered article of carbon is used as a heat radiation member, then thermal conductivity is improved, but bonding strength and durability under heat cycles deteriorate due to void formation and exfoliation
Solution Approach 1:
The patent utilizes a porous sintered carbon article with controlled porosity (10-30%) to achieve high thermal conductivity while maintaining structural integrity. The porous structure allows for metal impregnation that reinforces the carbon matrix without compromising thermal performance, resolving the contradiction between thermal conductivity and bonding strength
Solution Approach 2:
The patent creates a composite structure by impregnating metal materials into the porous carbon matrix. This metal-carbon composite enhances bonding strength and durability under heat cycles while preserving the high thermal conductivity of the carbon structure, preventing void formation and exfoliation at interfaces
2Strength
If metal impregnation is performed to enhance bonding strength, then durability under heat cycles is improved, but high temperature and high pressure are required making production difficult
Solution Approach 1:
The patent optimizes impregnation parameters including metal particle size (1-10 μm), impregnation temperature (500-800°C), and pressure (1-10 MPa) to achieve effective metal-carbon bonding without requiring extreme conditions. This makes the production process more feasible while maintaining bonding strength and durability
3Stability of the object's composition
If the carbon material has high porosity for thermal conductivity, then thermal expansion matching with ceramics is improved, but structural strength deteriorates under thermal stress
Solution Approach 1:
The patent creates a composite structure where metal materials are impregnated into the porous carbon matrix. The metal phase provides structural reinforcement to compensate for the strength reduction caused by porosity, while the carbon phase maintains thermal expansion matching with ceramics. This composite approach allows the material to withstand thermal stress without compromising either thermal compatibility or structural integrity
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 significantly enhances durability and maintains high thermal conductivity even under severe thermal stress conditions, reducing the occurrence of bonding failures and thermal resistance changes during heat cycles.
Implementation Method 1
bonded through solidification of a molten metal on the carbon material
Implementation Method 2
bonded by a brazing method
Implementation Method 3
transfers heat generated from a heat generator, such as a semiconductor element, to a cooling medium
Data Source
AI summary
To provide a heat radiation member having high durability that can favorably retain the thermal conductivity under application of heat cycles, suitable for mounting a semiconductor element of a power module. The heat radiation member includes a laminated structure including metal materials 21 and 22 and a carbon material 10 having the following property (A) bonded to each other; (A) in pressurizing one principal surface of a plate specimen having a thickness of 11 mm of the carbon material with nitrogen gas of 200 kPa, the carbon material having a gas permeability of the nitrogen gas permeating to the other principal surface with a flow rate of 5 L/min or more and 30 L/min or less per 0.01 m2 in terms of area of the pressurized principal surface, the pressurized principal surface having an area of 0.005 m2 or more.