Semiconductor Module Laser Welding Bus Bar Connection
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Solution Overview
Problem
Current semiconductor modules with high current carrying capacity face issues such as high production costs and risk due to the need for multiple parallel-connected chips, where a single defective chip can render the entire module defective, and existing joining methods like soldering and welding can be inefficient and damage the module, especially with high thermal conductivity materials like copper.
Innovation Solution
The semiconductor device employs laser welding to connect bus bars and printed circuit boards to semiconductor modules, eliminating the need for solder flux cleaning and reducing thermal impact, while using plated bus bars to enhance laser absorption and facilitate connections in confined spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple SiC semiconductor chips are arranged in parallel to achieve large current carrying capacity, then the current carrying capacity is improved, but the number of chips and assembly complexity increases significantly
Solution Approach 1:
The invention divides the large current carrying capacity requirement into multiple modular semiconductor modules, each with its own insulated circuit board and housing. These modules can be independently manufactured and then connected in parallel through bus bars, achieving the desired current capacity while maintaining manufacturing simplicity and enabling selective replacement of individual modules.
Solution Approach 2:
The invention employs a hierarchical structure where semiconductor chips are mounted on insulated circuit boards, which are then housed in protective casings with integrated heat sinks. Multiple such nested modules are connected in parallel to achieve the required current capacity, with each level providing functional integration and protection.
2Reliability
If soldering is used to connect bus bars to semiconductor modules, then electrical connection is achieved, but thermal impact damages the semiconductor chips
Solution Approach 1:
The invention introduces a copper plate as an intermediary component between the bus bar and the semiconductor module. The bus bar is laser-welded to the copper plate, which then makes electrical contact with the module terminals. This intermediary allows the use of laser welding instead of soldering, eliminating flux residue and reducing thermal damage to the chips while maintaining reliable electrical connection.
3Strength
If soldering with flux is used to connect bus bars, then connection strength is improved, but flux residue contaminates the semiconductor module
Solution Approach 1:
The invention replaces the chemical soldering process with laser welding, a thermal-mechanical process. The bus bar is laser-welded directly to a copper plate that contacts the module terminals, eliminating the need for solder flux entirely. This substitution maintains strong electrical connection while preventing flux residue contamination of the semiconductor components.
4Power
If a dedicated package with multiple chips is used, then current carrying capacity is achieved, but a single defective chip renders the entire module defective
Solution Approach 1:
The invention segments the high-current system into multiple independent semiconductor modules, each capable of operating autonomously. If one module fails, only that specific module needs to be replaced while the others continue to function, thereby improving system reliability while maintaining the required current carrying capacity through parallel operation of the remaining modules.
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 enhances the current carrying capacity of semiconductor devices, reduces production costs, and allows for efficient assembly without damaging the modules, enabling easy replacement of defective components and operation at high temperatures without gel sealing.
Implementation Method 1
the bus bars and the externally connecting terminals of the semiconductor modules are connected by means of laser welding
Data Source
AI summary
A semiconductor device composed of a plurality of semiconductor modules exhibiting a large current carrying capacity for a semiconductor device as a whole is disclosed. The connection between the plurality of semiconductor modules is conducted by means of optimum construction suited to the semiconductor device. The device comprises a semiconductor module having externally connecting terminals protruding out of a casing, bus bars electrically connecting the specific externally connecting terminals of the plurality of semiconductor modules arranged in parallel with each other, and a semiconductor module case covering and fastening the plurality of semiconductor modules connected with the bus bars. The bus bars and the externally connecting terminals of the semiconductor modules are joined by means of laser welding.