Ceramic Substrate With Boron-Rich Zones for Silver Diffusion Control
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Solution Overview
Problem
Existing techniques fail to sufficiently prevent the diffusion of the silver component from conductor traces into ceramic layers, leading to issues such as void formation, deformation, and color change in ceramic substrates.
Innovation Solution
Incorporating metal borides like lanthanum hexaboride (LaB6) and silicon hexaboride (SiB6) into the conductor paste, and increasing the boron atom concentration in adjacent regions of the ceramic layers to at least three times that of the central region, prevents silver diffusion by consuming oxygen and forming a boron-rich zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductor paste is used, then the firing process can be completed, but silver component diffuses into the ceramic layer causing voids, deformation, and color change
Solution Approach 1:
Metal boride particles are introduced as an intermediary substance between the silver component and the ceramic layer. These particles form a barrier that prevents direct contact and diffusion pathways, thereby blocking silver atoms from migrating into the ceramic layer during the firing process.
Solution Approach 2:
The invention converts the potentially harmful oxidation of silver into a beneficial process by controlling it to form a protective boron-rich zone. The metal boride reacts with oxygen that would otherwise oxidize silver, transforming a harmful oxidative environment into a protective barrier formation process.
2Reliability
If metal boride is added to conductor paste, then silver diffusion is prevented, but the device complexity increases
Solution Approach 1:
The invention changes the compositional parameters of the conductor paste by incorporating metal boride particles with specific properties (reactivity with oxygen, particle size, concentration). By optimizing these parameters, the paste achieves enhanced functionality without excessive complexity, as the added component serves multiple purposes.
Solution Approach 2:
The conductor paste is formulated as a composite material containing silver powder, glass powder, and metal boride particles. This composite structure combines the electrical conductivity of silver with the diffusion-blocking properties of metal boride, creating a multi-functional material that addresses both conductivity and diffusion prevention requirements.
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
Prevents silver diffusion, thereby improving the quality of ceramic substrates by reducing voids, deformation, and color changes, ensuring better structural integrity and performance.
Implementation Method 1
diffusion of the silver component is accelerated by oxidation of the silver component of the conductor trace
Implementation Method 2
a silver component of the conductor paste diffuses into the ceramic layer
Data Source
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AI summary
A ceramic substrate includes a ceramic layer mainly formed of a glass ceramic and a conductor trace mainly formed of silver (Ag). In an adjacent region located adjacent to the conductor trace, the concentration of boron atoms (B) contained in the ceramic layer increases toward the conductor trace.