Silver-Graded Metal-Ceramic Substrate for Thermal Shock Resistance
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Solution Overview
Problem
Metal-ceramic substrates experience peeling of the metal layer from the ceramic body due to different thermal expansion coefficients under extreme temperature changes, leading to reduced thermal shock resistance, which is crucial for electronic applications, particularly power electronics.
Innovation Solution
A metal-ceramic substrate design with a structuring region in the metal layer that includes both solid and non-solid materials, where the solid material adjacent to the upper half of the contour line has a higher silver content, ensuring a geometry where S(BCsolid)/S(BCtotal) > 60%, enhancing the adhesion between the metal and ceramic layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the metal layer is bonded to the ceramic body using conventional methods, then the bonding is achieved, but the metal layer peels off under extreme temperature changes due to different thermal expansion coefficients
Solution Approach 1:
The metal layer is segmented into multiple regions with different silver contents. The first region (adjacent to the ceramic body) has a higher silver content (≥70 wt%) than the second region, creating a gradient structure that accommodates thermal expansion differences and prevents peeling while maintaining bonding integrity.
Solution Approach 2:
The invention applies local quality by creating a non-uniform silver distribution within the metal layer. The region adjacent to the ceramic body contains a higher concentration of silver, which has superior thermal shock resistance properties, while other regions have lower silver content. This localized variation optimizes the bonding interface for thermal cycling conditions.
2Ease of manufacture
If a silver-containing contact area is applied to improve chip connection, then easier sintering or soldering is enabled, but the thermal shock resistance may be compromised without proper structuring
Solution Approach 1:
The metal layer is designed with local quality variations where the silver content differs between regions. The first region adjacent to the ceramic body has higher silver content for thermal shock resistance, while the contact area composition is optimized for chip bonding, achieving both ease of manufacture and reliability.
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 design significantly improves thermal shock resistance by maintaining the integrity of the metal-ceramic bond, preventing peeling and enhancing performance under temperature fluctuations.
Implementation Method 1
a copper foil is surface-coated with a copper compound (usually copper oxide) by reacting copper with a reactive gas (usually oxygen)
Implementation Method 2
the copper compound melts and wets the surface of the ceramic body, creating a stable, integral bond between the copper foil and the ceramic body
Implementation Method 3
Due to the different thermal expansion coefficients of the metal and the ceramic, repeated temperature changes can lead to the metal layer peeling off from the ceramic body
Data Source
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AI summary
The invention relates to a metal-ceramic substrate, an electronic component comprising a metal-ceramic substrate and a method for producing a metal-ceramic substrate.The metal-ceramic substrate comprises: a) a ceramic body having a main boundary surface, b) a metal layer having a main boundary surface, wherein the metal layer is bonded to the ceramic body in a planar manner, and wherein the metal layer has a structuring region which comprises (i) solid material in some regions and (ii) non-solid material in some regions, and c) a contact region arranged on the metal layer comprising silver, wherein in a cross-section through the metal-ceramic substrate perpendicular to the main boundary surface of the ceramic body, the structuring region has a geometry which satisfies the following requirement: SBCsolid/SBCtotal>60%, where: S (BCtotal) stands for the total length of the path between points B and C and S (BCsolid) stands for the length of the path between points B and C which intersects solid material.The solid material has an increased silver content in the area adjacent to the upper half of a contour line.