Ceramic-Copper Composite Crystal Orientation to Reduce Brazing Oozing
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Solution Overview
Problem
The manufacturing stability and yield of ceramic-metal composites, ceramic circuit boards, and power modules are hindered by brazing material oozing and defects in solder wettability, primarily due to issues with the bonding process.
Innovation Solution
A ceramic-copper composite is developed with a specific crystal orientation distribution in the copper layer, where S(102)% + S(101)% > S(111)% + S(112)% in a cut surface, reducing brazing material oozing by controlling the area ratios of copper crystals with specific crystal orientations, and using a brazing material containing Ag, Cu, Ti, Sn, or In to enhance bonding and reduce defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional brazing materials and processes are used to bond ceramic substrates and copper plates, then bonding is achieved, but brazing material oozing occurs and manufacturing yield decreases
Solution Approach 1:
The invention changes the chemical composition parameters of the brazing material by adding specific amounts of In (0.1-5 mass%) and Ga (0.1-5 mass%) to the Ag-Cu-Ti system, and controls the copper plate crystal orientation parameters (making <100> direction parallel to the normal direction). These parameter changes suppress brazing material oozing while maintaining bonding quality.
Solution Approach 2:
The invention creates a composite brazing material system combining Ag-Cu-Ti with In and Ga elements, forming a multi-element composite that leverages the low melting point and wetting properties of In/Ga to control oozing behavior while Ti provides strong bonding to the ceramic substrate.
2Reliability
If brazing material is used to bond ceramic and metal, then bonding is achieved, but defects in solder wettability occur due to oozing
Solution Approach 1:
By precisely controlling the brazing material composition (Ag: 90-99.8 mass%, Cu: 0.2-5 mass%, Ti: 0.1-5 mass%, In: 0.1-5 mass%, Ga: 0.1-5 mass%) and copper plate crystal orientation, the invention optimizes both bonding strength and solder wettability, eliminating the trade-off between these two quality attributes.
3Productivity
If standard manufacturing processes are used, then production is achieved, but manufacturing stability is poor due to oozing defects
Solution Approach 1:
The invention establishes specific parameter ranges for brazing material composition and copper plate crystal orientation that consistently prevent oozing defects, enabling stable mass production with high manufacturing reliability while maintaining productivity.
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 significantly decreases brazing material oozing, improves manufacturing stability, and increases the yield of ceramic-metal composites, ceramic circuit boards, and power modules by controlling copper crystal growth and enhancing bonding quality.
Implementation Method 1
a brazing material layer present between the ceramic layer and the copper layer
Implementation Method 2
bonding a ceramic substrate and a copper plate through a brazing material
Implementation Method 3
S(102)% + S(101)% > S(111)% + S(112)% in a cut surface, where S(102)% is an area ratio occupied by copper crystals having a crystal orientation of which an inclination from a crystal orientation of (102) plane is within 10°
Data Source
AI summary
A ceramic-copper composite having a flat plate shape, including: a ceramic layer; a copper layer; and a brazing material layer present between the ceramic layer and the copper layer, in which a specified Expression (1) is satisfied in a cut surface of the copper layer obtained when the ceramic-copper composite is cut at a plane perpendicular to a main surface of the ceramic-copper composite, where S(102)% is an area ratio occupied by copper crystals having a crystal orientation of which an inclination from a crystal orientation of (102) plane is within 10°, S(101)% is an area ratio occupied by copper crystals having a crystal orientation of which an inclination from a crystal orientation of (101) plane is within 10°, S(111)% is an area ratio occupied by copper crystals having a crystal orientation of which an inclination from a crystal orientation of (111) plane is within 10°, and S(112)% is an area ratio occupied by copper crystals having a crystal orientation of which an inclination from a crystal orientation of (112) plane is within 10°.