Metal-Ceramic Substrate Manufacturing via Pressure-Assisted Sintering
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Solution Overview
Problem
Current processes for manufacturing metal-ceramic substrates are costly and do not efficiently allow for the integration of metallization both on the surface and within the substrate, limiting the production of multilayer structures.
Innovation Solution
A process involving the formation of a metal-ceramic assembly with non-sintered ceramic and oxidized metal, followed by sintering at a temperature below the metal's bonding temperature under elevated pressure, and subsequent DCB bonding at a specific temperature range to create a metal-ceramic substrate, enabling efficient production of substrates with internal metallization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional DCB bonding process is used to attach metal to ceramic substrate, then metallization is achieved on the surface, but the process is costly and does not allow efficient integration of internal metallization
Solution Approach 1:
The patent combines the sintering of ceramic green bodies and the DCB bonding of metal to ceramic into a single integrated process step. By placing metal foils on ceramic green bodies before sintering, and then performing DCB bonding at the same temperature cycle, the process eliminates separate manufacturing steps, reduces cost, and enables internal metallization integration.
Solution Approach 2:
The metal foils are oxidized and placed on the ceramic green bodies in advance, before the final sintering and bonding step. This preliminary preparation allows the metal-ceramic interface to be ready for bonding when the temperature reaches the DCB range, enabling efficient integration of metallization structures.
2Temperature
If ceramic material is sintered at high temperature above metal bonding temperature, then complete ceramic sintering is achieved, but the metal bonding cannot be performed simultaneously
Solution Approach 1:
The patent applies pressure during the sintering process to enable ceramic sintering at lower temperatures (below the metal bonding temperature). This parameter change (adding pressure) allows the ceramic to densify and strengthen without reaching temperatures that would prematurely bond the metal, enabling subsequent DCB bonding in the same process cycle.
3Manufacturing precision
If multiple separate process steps are used for ceramic sintering and metal bonding, then each step can be optimized, but the production cost and process complexity increase
Solution Approach 1:
The patent merges ceramic sintering and metal DCB bonding into a single integrated process step by placing metal foils on ceramic green bodies before sintering. The temperature cycle is designed to first sinter the ceramic at lower temperature, then continue heating to bond the metal, eliminating the need for separate process equipment and steps.
4Adaptability or versatility
If metal foil is placed on ceramic green body before sintering, then internal metallization is enabled, but the metal may oxidize or deform during high temperature sintering
Solution Approach 1:
The patent applies pressure during sintering to enable ceramic densification at lower temperatures, reducing the thermal exposure of the metal foil. The pressure-assisted sintering allows the ceramic to achieve sufficient strength at temperatures that minimize metal oxidation and deformation, while still enabling subsequent DCB bonding.
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 process significantly reduces production costs and complexity, allowing for the creation of multilayer metal-ceramic substrates with buried metallization, enhancing reliability and lifetime by lowering sintering temperatures and applying pressure to minimize residual porosity and mechanical stresses.
Implementation Method 1
subsequently sintering the ceramic material of the metal-ceramic assembly at a sintering temperature below a bonding temperature of the metal body and at a sintering pressure higher than atmospheric air pressure
Implementation Method 2
finally, DCB bonding the metal body of the metal-ceramic assembly to the sintered ceramic body at a bonding temperature between 1025 °C and 1083 °C
Implementation Method 3
applying pressure to minimize residual porosity
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a process for the manufacture of a metal-ceramic substrate (2, 12, 15), comprising at least the following steps: - forming a metal-ceramic assembly (3, 19) of an at least partially non-sintered ceramic material (4) and at least an oxidized metal body (5), which at least partially is in contact with the ceramic material (4); - sintering the ceramic material (4) of the metal-ceramic assembly (3, 19) at a sintering temperature below a bonding temperature of the metal body (5) and under a sintering pressure higher than the atmospheric air pressure for a predictable sintering period to form a ceramic body (11) from the ceramic material (4); - bonding the metal body (5) of the metal-ceramic assembly (3, 19) to the sintered ceramic body (11) at bonding temperature for a predictable bonding period to form the metal-ceramic substrate (2, 12, 15); and - cooling the metal-ceramic substrate (2, 12, 15) to room temperature.