Metal-Ceramic Substrate Bonding With a Separated Active Metal Layer
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Solution Overview
Problem
Existing methods for manufacturing metal-ceramic substrates using active solder processes require thick solder layers due to the presence of active metals, which are costly and limit the minimum layer thickness, hindering efficient bonding and increasing material consumption.
Innovation Solution
A method involving a multilayer solder system with a separate active metal layer and a solder layer free of melting point-lowering elements, allowing for thinner solder layers and improved bonding efficiency by separating the active metal from the solder layer, enabling reduced material usage and simplified patterning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a solder layer containing active metal is used for bonding metal layer to ceramic layer, then strong adhesion is achieved, but the solder layer thickness must be large which increases material consumption and cost
Solution Approach 1:
The solder system is divided into two separate functional layers: an active metal layer (containing Ti, Zr, Hf, Nb, Ce, or their oxides/nitrides) and a solder layer (free of active metals). The active metal layer provides adhesion to the ceramic substrate, while the solder layer provides bonding strength and electrical conductivity. This segmentation allows each layer to be optimized independently, enabling thin solder layers without compromising adhesion.
Solution Approach 2:
The active metal is extracted from the solder layer and placed in a separate active metal layer. This extraction removes the constraint that previously required thick solder layers to ensure adequate active metal content for adhesion. The solder layer can now be made thin while the active metal layer provides the necessary adhesion function.
2Ease of manufacture
If active metal is included in the solder layer, then chemical reaction with ceramic is enabled, but the minimum layer thickness is limited by manufacturing constraints
Solution Approach 1:
By separating the active metal layer from the solder layer, the invention allows the solder layer thickness to be determined by electrical conductivity requirements rather than manufacturing constraints. The active metal layer independently provides the chemical reaction capability with the ceramic substrate.
Solution Approach 2:
The invention changes the compositional parameters of the solder layer by removing active metals, allowing the solder layer thickness to be reduced to minimal values (e.g., 1-10 μm) while maintaining bonding functionality through the separate active metal layer.
3Reliability
If thick solder layers are used to ensure adequate active metal content, then bonding reliability is improved, but material cost and processing time increase
Solution Approach 1:
The segmentation of active metal and solder into separate layers allows thin solder layers to be used, which reduces processing time for subsequent steps such as patterning, etching, and metallization while maintaining bonding reliability through the dedicated active metal layer.
Solution Approach 2:
Extracting active metal from the solder layer enables the solder layer to be made thin without compromising bonding reliability. The active metal layer provides sufficient adhesion even at reduced thicknesses, allowing faster processing.
4Strength
If active metals are used in the solder layer, then chemical bonding to ceramic is achieved, but material cost increases due to expensive active metal content
Solution Approach 1:
By separating active metal from solder material, the invention allows precise control of active metal quantity in a thin layer, reducing overall active metal consumption while maintaining chemical bond strength. The solder layer can be made thin and inexpensive.
Solution Approach 2:
Extracting active metal from the bulk solder layer concentrates it in a thin dedicated layer, reducing total active metal usage. The solder layer becomes a separate, thinner component that does not require expensive active metal content.
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 enables the production of thinner, more cost-effective solder layers, accelerating the bonding process and reducing material consumption while maintaining strong adhesion and thermal conductivity, thus enhancing the manufacturing efficiency of metal-ceramic substrates.
Implementation Method 1
This active metal, which is for example at least one element of the group Hf, Ti, Zr, Nb, Ce, establishes a connection between the brazing alloy and the ceramic by chemical reaction
Implementation Method 2
bonding the at least one metal layer to the at least one ceramic layer via the solder system by means of an active solder process
Data Source
AI summary
A method for manufacturing a metal-ceramic substrate (1) includesproviding a ceramic layer (10), a metal layer (20) and a solder layer (30)coating the ceramic layer (10) and/or the metal layer (20) and/or the solder layer (30) with an active metal layer (40),arranging the solder layer (30) between the ceramic layer (10) and the metal layer (20) along a stacking direction (S), forming a solder system (35) comprising the solder layer and the active metal layer (40), wherein a solder material of the solder layer (30) is free of a melting point lowering material andbonding the metal layer (20) to the ceramic layer (10) via the solder system (35) by means of an active solder process.