Copper-Diamond Ceramic Substrate for Thermal Stress Control
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Solution Overview
Problem
The challenge is to reduce the difference in thermal expansion coefficients between conductive and ceramic members in substrates, which can lead to stress and breakage in light-emitting devices due to temperature changes.
Innovation Solution
A substrate design incorporating a conductive member with regions of copper and diamond, and a ceramic member separated by a region containing copper and active metals like titanium, hafnium, or niobium, with diamond in the vicinity of these regions, reducing thermal expansion disparities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive member containing copper and a ceramic member are used in a substrate, then good electrical conductivity and structural stability are achieved, but a large difference in thermal expansion coefficient between the conductive member and ceramic member causes stress and breakage under temperature changes
Solution Approach 1:
The conductive member is divided into three regions with different compositions: a first region with copper and diamond particles, a second region with copper as main component, and a third region with copper and active metal. This local variation in material composition allows different parts of the conductive member to have different thermal expansion characteristics, reducing overall thermal stress while maintaining electrical conductivity.
Solution Approach 2:
The conductive member uses a composite structure combining copper with diamond particles in the first region and active metal in the third region. This composite material approach creates a material with tailored thermal and electrical properties, specifically reducing thermal expansion coefficient mismatch with the ceramic member while maintaining good electrical conductivity.
2Reliability
If diamond particles are added to the conductive member to reduce thermal expansion coefficient, then thermal expansion mismatch with ceramic member is reduced, but the complexity of manufacturing the conductive member increases
Solution Approach 1:
The conductive member is segmented into three distinct regions with different compositions. The first region contains copper and diamond particles, the second region contains copper as main component, and the third region contains copper and active metal. This segmentation allows each region to be optimized for specific functions while simplifying the overall manufacturing process through a systematic structure.
Solution Approach 2:
The invention changes the material parameters (composition and structure) of the conductive member by introducing diamond particles and active metal in specific regions. This parameter change reduces the thermal expansion coefficient of the conductive member to match the ceramic member, improving thermal expansion compatibility while maintaining manufacturability through controlled material distribution.
3Reliability
If a third region containing copper and active metal is introduced between the first region and ceramic member, then thermal expansion coefficient difference is further reduced, but the device structure becomes more complex
Solution Approach 1:
The third region is specifically designed with copper and active metal composition to have thermal expansion properties that bridge between the first region (copper-diamond) and the ceramic member. This local quality optimization in the third region further reduces thermal expansion coefficient difference while maintaining a systematic three-region structure that is manageable in terms of device complexity.
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 design minimizes thermal stress and enhances heat dissipation, improving the reliability and durability of light-emitting devices by reducing thermal expansion and contraction effects.
Implementation Method 1
a first region containing copper and diamond
Implementation Method 2
disposing, via an active metal brazing material, a ceramic member on a lateral surface of each of the plurality of protrusions
Implementation Method 3
sintering the first raw material and the second raw material
Data Source
AI summary
A substrate includes a conductive member including first to third regions and a ceramic member. The first region contains copper and diamond. The second region contains copper as a main component. The third region is disposed between the first and second regions and the ceramic member, and contains copper and at least one selected from the group consisting of titanium, hafnium, zirconium, niobium, cerium, and magnesium. The diamond disposed in the first region in a vicinity of the third region is in contact with the third region. In a cross section, the first region includes a first portion and a second portion located between the first portion and the second region in a first direction, and an area occupied by diamond per unit area in the second portion is smaller than an area occupied by diamond per unit area in the first portion.