Metal-Ceramic Via Formation to Prevent Voids in Conductive Substrates
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Solution Overview
Problem
Existing methods for producing metal-ceramic substrates with electrically conductive vias face challenges in ensuring reliable electrical conductivity and mass-producibility, often resulting in voids between metal layers that affect conductivity.
Innovation Solution
A method involving attaching metal layers to ceramic substrates with a metal-containing substance introduced into holes, subjected to a high-temperature step above 500°C, allowing partial wetting and forming a bond with the ceramic layer to create electrically conductive vias, ensuring reliable connections and avoiding voids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal layers are attached to ceramic substrates using conventional bonding methods, then metallization is achieved, but voids form between metal layers affecting electrical conductivity
Solution Approach 1:
The method introduces a metal-containing substance into the hole before attaching the second metal layer, performing the via formation action in advance. This preliminary filling ensures that when the high-temperature step is applied, the metal substance is already positioned to form conductive bridges without creating voids, thus improving electrical conductivity while maintaining process efficiency
Solution Approach 2:
The invention applies a high-temperature step above 500°C to activate the metal-containing substance and achieve proper wetting of the ceramic surface. This parameter change (temperature) transforms the metal substance from a non-adherent state to a bonded state, ensuring complete filling of vias and elimination of voids, thereby improving electrical conductivity
2Reliability
If metal-containing substance is introduced into holes before high-temperature step, then electrical conductivity is improved, but process steps increase
Solution Approach 1:
The invention combines multiple functions into the high-temperature step above 500°C: it simultaneously activates the metal-containing substance, achieves proper wetting of the ceramic surface, and forms the electrical connection. This merging of functions into a single step improves electrical conductivity without proportionally increasing process complexity
Solution Approach 2:
The metal-containing substance introduced into the hole acts as an intermediary material that facilitates the electrical connection between metal layers. This intermediary substance is specifically designed to be activated at the high-temperature step, bridging the gap between metal layers and ensuring reliable conductivity without requiring additional specialized process steps
3Strength
If high-temperature step above 500°C is applied, then wetting and bonding are achieved, but thermal stress increases
Solution Approach 1:
The invention specifies a precise temperature threshold of above 500°C for the high-temperature step. This parameter change is critical: it is high enough to activate the metal-containing substance and achieve proper wetting and bonding (improving strength), but controlled to minimize excessive thermal stress. The temperature parameter is optimized to balance bonding quality and stress management
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
This method enhances the quality and reliability of electrically conductive vias, ensuring effective electrical conductivity and enabling mass production of metal-ceramic substrates with improved connectivity between metal layers.
Implementation Method 1
the metal-containing substance wets the ceramic layer at least partially with a wetting angle of less than 90°
Data Source
AI summary
A method for producing a metal-ceramic substrate with a plurality of electrically conductive vias includes: attaching a first metal layer in a planar manner to a first surface side of a ceramic layer; after attaching the first metal layer, introducing a copper hydroxide or copper acetate brine into a plurality of holes in the ceramic layer delimiting a via, to form an assembly; converting the copper hydroxide or copper acetate brine into copper oxide; subjecting the assembly to a high-temperature step above 500° C. in which the copper oxide forms a copper body in the plurality of holes; and after converting the copper hydroxide or copper acetate brine into the copper oxide, attaching a second metal layer in a planar manner to a second surface side of the ceramic layer opposite the first surface side. The copper body produces an electrically conductive connection between the first and the second metal layers.