Power Module Substrate Brazing Method for Narrow Conductive Patterns
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Solution Overview
Problem
Existing power module substrates face challenges in achieving a compact design with narrow conductive patterns while supporting large currents and high voltages, as etching methods require increased processing time and cost, and press punching methods lead to surface roughness issues causing electrical connectivity problems.
Innovation Solution
A method involving the use of a brazing sheet and volatile organic liquid to temporarily fix and join a conductive pattern member with a ceramics substrate, eliminating the need for etching and ensuring accurate positioning, while using brazing filler metal to cover rising surfaces and improve joining strength and reduce surface roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the conductive pattern is formed by etching the base material, then the conduction area can be increased, but the width of the lower part of the conductor is increased and processing time is extended
Solution Approach 1:
The conductive pattern member is punched from the base material before being placed on the ceramics substrate. This preliminary punching action defines the final conductor width without requiring subsequent etching, thereby reducing processing time while maintaining the desired conduction area.
Solution Approach 2:
The conductive pattern is separated into a distinct conductive pattern member that is punched from the base material. This segmentation allows the conductor to be formed independently with precise width control, eliminating the need for time-consuming etching processes to define the conductor boundaries.
2Area of moving object
If the conductive pattern is formed by etching, then the conduction area can be increased, but the line width of the conductive pattern cannot be reduced for compact design
Solution Approach 1:
The conductive pattern member is punched with the final desired width before placement on the ceramics substrate. This preliminary formation of the conductor at its final dimensions allows for narrow line widths suitable for compact designs while maintaining adequate conduction area through optimized conductor geometry.
Solution Approach 2:
The chemical etching process is replaced with a mechanical punching process. This substitution enables precise control of conductor width through the punching die geometry, allowing for narrower and more consistent line widths compared to etching, which tends to produce tapered conductors.
3Productivity
If press punching is used to form the conductive pattern, then production efficiency is improved, but surface roughness causes electrical connectivity problems
Solution Approach 1:
A brazing sheet is introduced as an intermediary layer between the punched conductive pattern member and the ceramics substrate. This brazing sheet serves as a mediator that bridges the connection, compensating for surface roughness issues from punching while maintaining electrical connectivity through the brazing process.
Solution Approach 2:
The surface condition of the conductive pattern member is changed through the brazing process. The brazing operation modifies the interface characteristics, allowing the rough surface from punching to achieve reliable electrical connectivity through the brazed joint rather than requiring a smooth surface.
4Ease of manufacture
If the conductive pattern member is punched from base material, then production cost is reduced, but positioning accuracy may be compromised
Solution Approach 1:
The brazing sheet acts as an intermediary that facilitates accurate positioning of the punched conductive pattern member on the ceramics substrate. During the brazing process, the sheet allows for precise alignment and secure attachment, maintaining positioning accuracy despite the cost-effective punching method used to create the conductor.
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 high-efficiency production of power module substrates with reduced line width, improved joining strength, and prevention of electrical connectivity issues, allowing for compact, high-current, high-voltage power modules at lower costs.
Implementation Method 1
temporarily fixing a brazing sheet on a surface of a ceramics substrate by a surface tension of a volatile organic liquid, temporarily fixing a conductive pattern member punched from a base material on the other surface of the brazing sheet by the surface tension of the volatile organic liquid
Implementation Method 2
heating the brazing sheet and the conductive pattern member so as to volatilize the volatile organic liquid
Implementation Method 3
melting the brazing sheet to join the conductive pattern member with the surface of the ceramics substrate
Implementation Method 4
melting the brazing sheet to join the conductive pattern member with the surface of the ceramics substrate
Data Source
AI summary
A high-efficiency production method for a power module substrate with reduced line width of a conductive pattern provides an insulation substrate suitable for realizing a large current and a high voltage of a power module. According to the method, a brazing sheet is temporarily fixed on a first surface of a ceramics substrate by surface tension of a volatile organic liquid. The brazing sheet is also temporarily fixed on the first surface of a conductive pattern member punched from a base material by surface tension of same type of volatile organic liquid. The brazing sheet and the conductive pattern member are heated so as to volatilize the volatile organic liquid and a pressure is applied to the conductive pattern member in its thickness direction. The brazing sheet is melted to join the conductive pattern member with the first surface of the ceramics substrate.