Metal-Ceramic Substrate Hot Isostatic Pressing
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Solution Overview
Problem
Existing methods for producing metal-ceramic substrates, such as the DCB process and active soldering, face challenges in achieving a cavity-free and cost-effective direct connection between metal and ceramic layers, leading to impaired partial discharge resistance and high process complexity.
Innovation Solution
A method involving the stacking of metal layers with projecting edges over a ceramic layer, followed by hot-isostatic pressing at high pressure and temperature, to form a gas-tight metal container that encapsulates the ceramic layer, allowing for a direct and imperfection-free connection using the HIP process, which enables thinner metal layers and adjustable grain sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the DCB process is used to connect metal layers to ceramic layers, then the thermal properties are maintained, but process-related imperfections and micro-cavities arise that impair partial discharge resistance
Solution Approach 1:
The patent applies hot isostatic pressing with specific parameter ranges (pressure: 500-2000 bar, temperature: 300°C to melting temperature of metal layers) to transform the connection quality between metal and ceramic layers. This parameter change eliminates micro-cavities and imperfections while maintaining thermal properties, directly resolving the contradiction between reliability and manufacturing precision.
Solution Approach 2:
The patent uses a composite approach by combining metal layers with ceramic layers through hot isostatic pressing to create a metal-ceramic substrate with superior properties. The composite structure achieves both good thermal properties and high partial discharge resistance by eliminating connection imperfections through the HIP process.
2Ease of manufacture
If active soldering method is used to connect metal layers to ceramic layers, then a direct connection is achieved, but the process becomes costly and complex due to required hard solder
Solution Approach 1:
The patent extracts the hard solder from the connection process entirely. Instead of using active soldering with costly hard solders containing active metals, the invention uses hot isostatic pressing to create a direct metal-to-ceramic connection. This eliminates the need for hard solder while maintaining connection strength, resolving the contradiction between ease of manufacture and reliability.
Solution Approach 2:
The patent replaces the chemical bonding mechanism of active soldering with a mechanical-thermal process (hot isostatic pressing). The HIP process uses high pressure and temperature to create direct diffusion bonding between metal and ceramic layers, eliminating the need for chemical reactions with active metals and simplifying the manufacturing process while maintaining connection integrity.
3Loss of substance
If thick metal layers are used in DCB process, then sufficient connection strength is achieved, but material usage and process complexity increase
Solution Approach 1:
The patent uses hot isostatic pressing parameters (high pressure up to 2000 bar and controlled temperature) to enhance the adhesive strength of thin metal layers to ceramic substrates. This parameter change allows achieving sufficient connection strength with significantly reduced metal layer thickness compared to DCB process, thereby reducing material loss without sacrificing strength.
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 approach results in a resource-saving, cavity-free direct connection with enhanced adhesive strength and reduced process complexity, enabling the use of thinner metal layers and improved partial discharge resistance, while minimizing the need for costly hard solders.
Implementation Method 1
the metal layers forming the metal container with the ceramic layer accommodated in the container interior are hot isostatically pressed together in a treatment chamber at a gas pressure between 500 and 2000 bar and at a process temperature between 300° C. and the melting temperature of the metal layers to produce a connection
Implementation Method 2
the exposure of the plate stack to high gas pressure in the protective gas atmosphere under the stated temperature conditions leads, amongst other things, to the fact that the connection between the plates is for the most part free from micro-cavities
Implementation Method 3
the first and second metal layers are deformed towards each other in the region of the projecting free edge sections and directly connected to each other in order to form a gas-tight, sealed metal container enclosing a container interior for accommodating the ceramic layer
Data Source
AI summary
The invention relates to a method for producing a metal-ceramic substrate including first and second metallizations and at least one ceramic layer incorporated between the first and second metallizations. Advantageously, first and second metal layers and the at least one ceramic layer are stacked superposed, and in such a way that the free edge sections, of the first and second metal layers respectively, project beyond the edges of the at least one ceramic layer and the first and second metal layers are deformed toward each other in the region of the projecting free edge sections and directly connected to each other in order to form a gas-tight, sealed metal container enclosing a container interior for receiving the at least one ceramic layer. Subsequently, the metal layers forming the metal container with the at least one ceramic layer received in the container interior are hot isostatically pressed together in a treatment chamber at a gas pressure between 500 and 2000 bar and at a process temperature between 300° C. and the melting temperature of the metal layers for producing a preferably flat connection of at least one of the metal layers and the at least one ceramic layer, and at least the projecting free edge sections, which are connected to each other, of the metal layers for forming the first and second metallization are subsequently removed.