Thin Solder Layer for Ceramic Composite Bonding
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Solution Overview
Problem
Existing methods for producing composite materials, such as circuit boards with metallization layers on ceramic bases, face challenges in achieving ideal thermal and mechanical properties due to the geometry of the reaction layer and high silver consumption, leading to costly and inefficient processes.
Innovation Solution
A method involving a thin solder layer with a thickness of less than 12 μm, applied in a fully planar manner using roll cladding, which reduces silver consumption and enhances mechanical and thermal properties by forming a durable reaction layer through controlled melting and intermetallic phase formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional soldering method with thicker solder layer is used, then the connection between metal foil and ceramic substrate is achieved, but the thermal and mechanical properties of the composite material are not ideal
Solution Approach 1:
The invention changes the critical parameter of solder layer thickness from conventional thicker layers to a specific thin range of 5-15 μm. This parameter change enables the formation of an ideal reaction layer geometry that simultaneously achieves excellent thermal and mechanical properties, resolving the contradiction between reliability and manufacturing precision.
Solution Approach 2:
The invention applies preliminary action by pre-coating the metal foil with a specifically formulated active solder paste containing reactive elements (Ti, Zr, Hf, Nb, or Ce) before the soldering process. This preliminary preparation ensures that during heating, an ideal reaction layer forms automatically between the metal and ceramic, achieving optimal thermal and mechanical properties without requiring complex post-processing.
2Reliability
If active solder paste with silver is used for serigraphy application, then the connection is achieved, but the production cost increases due to high silver consumption
Solution Approach 1:
The invention changes the solder layer thickness parameter to 5-15 μm, which is significantly thinner than conventional solder layers. This parameter change directly reduces silver consumption by approximately 50% or more while maintaining connection quality, as the active elements in the optimized paste formulation ensure reliable bonding even at reduced thickness.
Solution Approach 2:
The invention applies local quality by concentrating the reactive elements (Ti, Zr, Hf, Nb, or Ce) specifically at the interface between metal and ceramic where they are needed for reaction layer formation. This localized distribution of active elements ensures effective bonding with reduced overall silver content, addressing both connection quality and cost concerns.
3Ease of manufacture
If rolled solder belts are used, then the application process is simplified, but an ideal formation of the reaction layer is not possible
Solution Approach 1:
The invention changes the solder layer thickness parameter to a precise range of 5-15 μm, which is thinner and more controlled than what can be achieved with conventional rolled solder belts. This parameter change enables ideal reaction layer formation by ensuring sufficient reactive element concentration at the interface, while the use of screen printing or similar precision application methods maintains ease of manufacture through automated processing.
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 method results in composite materials with improved mechanical and thermal stability, reduced silver usage, and cost-effectiveness, enabling better heat dissipation and structural integrity for electronic power modules.
Implementation Method 1
heating the base material and the additional layer arranged on the first surface to at least partially melt the solder layer
Implementation Method 2
Said active metal which is for example at least one element of the group Hf, Ti, Zr, Nb, or Ce, produces a connection between the solder and the ceramic via chemical reaction
Data Source
AI summary
A method for producing a composite material comprising a planar base material to which an additional layer is applied on one side or both sides via a solder layer, characterized by: providing the base material, wherein the base material has a first surface on at least one side; providing the additional layer and arranging the solder layer between a second surface of the additional layer and the first surface such that when the additional layer is deposited on the first surface, the first surface of the base material is covered by the solder layer in a planar manner; wherein a thickness of the solder layer between the base material and the additional layer is smaller than 12 μm; heating the base material and the additional layer on the first surface to at least partially melt the solder layer; and connecting the base material to the at least one additional layer.