Ceramic Substrate Joining Structure with Stress Relaxation Insert
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Solution Overview
Problem
The existing joining structure between a ceramic substrate and a power supply connector is prone to low bending strength and oxidation, leading to a short lifespan due to exposure and lack of sealing, which compromises the electrical connection and strength over time.
Innovation Solution
A counterbore with a large-diameter and small-diameter part is formed in the ceramic substrate, incorporating a stress relaxation insert member and a brazing member that seals the gap between the counterbore and the insert member, enhancing the joining strength and sealing the area to prevent oxygen ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the metal member and power supply connector are directly joined in the bottom portion of the opening, then the structure is simple, but the joining strength against bending stress is low and the joining part is prone to disconnection
Solution Approach 1:
A stress relaxation insert member is introduced as an intermediary component between the metal member and power supply connector. This insert member is fitted into a counterbore structure in the ceramic substrate, providing mechanical support and stress distribution. The brazing member then connects the power supply connector to this insert member, creating a more robust joining structure that can withstand bending stresses while maintaining electrical connectivity.
2Reliability
If the metal member is exposed in the opening, then electrical connection is achieved, but oxygen enters from the opening and deteriorates the metal member, shortening the joining part's lifespan
Solution Approach 1:
The brazing member serves to seal the gap between the counterbore and the stress relaxation insert member, creating a sealed environment that prevents oxygen from reaching the metal member. This sealing action protects the metal member from oxidation while maintaining the electrical connection pathway through the stress relaxation insert member, thereby extending the joining part's lifespan.
3Reliability
If a stress relaxation insert member and brazing member are used to seal the gap, then joining strength and oxidation resistance are improved, but the structure becomes more complex
Solution Approach 1:
The stress relaxation insert member is nested within the counterbore structure of the ceramic substrate, and the brazing member seals the gap between these nested components. This nested arrangement allows the additional protective and strengthening elements to be integrated within the existing structure rather than adding external components, thereby improving reliability while minimizing increases in overall structural 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
The solution significantly improves the bending strength and extends the lifespan of the joining part by maintaining high joining strength and good electrical connection for an extended period, as demonstrated by thermal and conduction cycle tests.
Implementation Method 1
a brazing member, which connects the power supply connector to the stress relaxation insert member, and which seals a gap between the counterbore and the stress relaxation insert member
Data Source
AI summary
A joining structure joining a ceramic substrate having a metal member buried therein and a power supply connector which supplies power to the metal member is provided. The joining structure includes a counterbore, a stress relaxation insert member, and a brazing member. The counterbore is formed in the ceramic substrate having a large-diameter part and a small-diameter part formed at a bottom center portion of the large-diameter part. At least a part of the metal member is exposed from a bottom of the small-diameter part. The stress relaxation insert member has a body part and a protrusion and is provided in the counterbore so that the body part and the protrusion are fitted into the large-diameter part and the small-diameter part, respectively. The brazing member connects the power supply connector to the stress relaxation insert member, and seals a gap between the counterbore and the stress relaxation insert member.