Metal-Ceramic Substrate Silver Contact Structuring for Thermal Shock
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Solution Overview
Problem
Existing metal-ceramic substrates suffer from low thermal shock resistance due to detachment of the metal layer from the ceramic body under repeated temperature changes, primarily because of differing thermal expansion coefficients and inadequate masking during silver-plating, leading to the removal of solid material near the ceramic body.
Innovation Solution
A metal-ceramic substrate design with a structuring region comprising partially solid and non-solid material, where the solid material adjacent to the upper half of the contour line has a higher silver content, ensuring a geometry that enhances thermal shock resistance by maintaining a strong bond 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 (DCB or soldering), then a stable bond is achieved, but the metal layer detaches from the ceramic body under repeated temperature changes due to different thermal expansion coefficients
Solution Approach 1:
The patent applies local quality by creating a structuring region with non-solid material (voids, pores, or recesses) specifically at the interface between the metal layer and ceramic body. This localized structural modification allows the metal layer to accommodate thermal expansion differences without compromising the overall bond strength, thereby resolving the contradiction between maintaining bond strength and resisting thermal shock.
Solution Approach 2:
The patent utilizes porous materials by introducing non-solid material (voids or pores) into the structuring region of the metal layer. This porous structure acts as a buffer zone that absorbs thermal stress generated during temperature cycling, preventing detachment while maintaining the integrity of the metal-ceramic bond.
2Ease of manufacture
If the metal-ceramic substrate is provided with a silver-containing contact area by partial application of silver coating, then the chip can be easily connected using sintering or soldering, but the solid material near the ceramic body is removed during the silver-plating process
Solution Approach 1:
The patent applies preliminary action by first creating the structuring region with non-solid material before applying the silver-containing coating. This pre-structured interface protects the metal-ceramic bond area from material removal during subsequent silver-plating processes, ensuring that the solid material near the ceramic body is preserved while still enabling easy chip connection through the silver contact areas.
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 enhanced design significantly improves thermal shock resistance, preventing detachment of the metal layer from the ceramic body, as evidenced by superior performance in thermal cycling tests compared to conventional methods.
Implementation Method 1
a copper foil is provided superficially 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
Implementation Method 3
the copper compound melts and wets the surface of the ceramic body, so that a stable cohesive bond is achieved
Implementation Method 4
The role of the active metal is to react with the ceramic material and to thus facilitate a bonding of the ceramic material to the remaining solder, forming a reaction layer
Implementation Method 5
Due to the different thermal expansion coefficients of the metal and the ceramic, repeated temperature changes can lead to the metal layer detaching from the ceramic body
Data Source
AI summary
A metal-ceramic substrate, to an electronic component comprising a metal-ceramic substrate, and to a method for producing a metal-ceramic substrate. The metal-ceramic substrate comprises: a) a ceramic body comprising a primary boundary surface, b) a metal layer comprising a primary boundary surface, wherein the metal layer is connected over its surface to the ceramic body, and wherein the metal layer comprises a structuring region which comprises (i) partially solid material and (ii) partially non-solid material, and c) a contact area, comprising silver, arranged on the metal layer, wherein in a cross-section through the metal-ceramic substrate perpendicular to the primary boundary surface of the ceramic body, the structuring region has a geometry as described in the patent.