Ceramic Circuit Substrate With Ag-Cu Through Conductor
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Solution Overview
Problem
The increasing heat generation in densely packed electronic devices poses a challenge for effective heat dissipation and junction reliability on ceramic-based circuit substrates, as existing solutions fail to adequately manage heat transfer and prevent separation between the ceramic base and metal layers.
Innovation Solution
A circuit substrate with a through conductor composed of silver and copper, featuring a eutectic and non-eutectic region, is used, where the eutectic region is located in the metal layer side and the non-eutectic region in the center, enhancing thermal conductivity and reducing surface indentation during heat treatment, thereby improving heat dissipation and junction reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a through hole with conductor is used to improve heat dissipation, then heat dissipation performance is improved, but surface indentation and junction reliability deteriorate
Solution Approach 1:
The patent applies local quality by creating a non-eutectic region at the center of the through conductor and a eutectic region at the surface. The central non-eutectic region (with Cu-rich composition) maintains structural integrity and reduces indentation, while the surface eutectic region (with balanced Ag-Cu composition) ensures good thermal conductivity and bonding. This spatial variation in material composition resolves the contradiction between heat dissipation and junction reliability.
Solution Approach 2:
The patent changes the compositional parameters of the through conductor by controlling the Ag-Cu ratio to be 60-80 mass% Ag in the central non-eutectic region and achieving eutectic composition (72 mass% Ag) in the surface region. This parameter variation allows the material to exhibit different properties at different locations, enabling both good thermal conductivity and reduced surface indentation.
2Temperature
If metal paste with expanding agent is used to form through conductor, then heat dissipation is improved, but surface indentation increases
Solution Approach 1:
The patent applies local quality by creating a non-eutectic region at the center of the through conductor and a eutectic region at the surface. The central non-eutectic region (with Cu-rich composition) maintains structural integrity and reduces indentation, while the surface eutectic region (with balanced Ag-Cu composition) ensures good thermal conductivity and bonding. This spatial variation in material composition resolves the contradiction between heat dissipation and junction reliability.
Solution Approach 2:
The patent changes the compositional parameters of the through conductor by controlling the Ag-Cu ratio to be 60-80 mass% Ag in the central non-eutectic region and achieving eutectic composition (72 mass% Ag) in the surface region. This parameter variation allows the material to exhibit different properties at different locations, enabling both good thermal conductivity and reduced surface indentation.
3Productivity
If electronic components are densely integrated, then device functionality is improved, but heat generation increases
Solution Approach 1:
The patent introduces the through conductor as an intermediary heat dissipation path. The unique Ag-Cu composition with central non-eutectic and surface eutectic regions creates an optimized thermal pathway that efficiently conducts heat away from densely integrated components, enabling high integration without excessive heat accumulation.
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 substrate achieves efficient heat dissipation and reliable junctions due to high thermal conductivity and reduced surface indentation, ensuring effective heat transfer and maintaining structural integrity under thermal stress.
Implementation Method 1
The through conductor contains silver and copper as main components... The eutectic region is disposed in a metal layer side region... improving heat dissipation
Implementation Method 2
The through conductor includes a eutectic region of silver and copper and a non-eutectic region of silver and copper... reducing surface indentation during heat treatment
Data Source
Figure 1
Figure 2~3A
Figure 3B~4
AI summary
In the present disclosure, a circuit substrate includes a base, a through conductor, and a metal layer. The base is formed of ceramics, and includes a first face, a second face and a through hole penetrating from the first face to the second face of the base. The through conductor contains silver and copper as main components. The through conductor is disposed inside the through hole, and includes a plurality of surfaces. The metal layer is in contact with at least one surface of the through conductor. The through conductor includes a eutectic region of silver and copper and a non-eutectic region of silver and copper. The eutectic region of silver is disposed in a metal layer side region of a diametrically center region of the through conductor. The non-eutectic region is disposed in a central region of the diametrically center region of the through conductor.