Power Semiconductor Module Contact Elements for High Current Density
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Solution Overview
Problem
Existing power semiconductor module contacting methods face challenges with high current-carrying capacity, reliability, and space efficiency, particularly in dense arrangements, due to limitations in ultrasonic wire bonds and clip techniques.
Innovation Solution
The power semiconductor module employs elongate metal contact elements with first and second projections, forming a flat, bent piece for secure and space-saving connections, allowing for both soft soldering and ultrasonic welding, which simplifies handling and enhances current-carrying capacity by ensuring precise alignment and eliminating the need for additional solder preforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If ultrasonic wire bonds are used for contacting semiconductor chips, then automation is improved, but current carrying capacity is reduced due to punctiform contact points
Solution Approach 1:
The contact element is divided into multiple parallel bonding contacts (at least two) that are attached in parallel to the semiconductor chip. This segmentation distributes the current across multiple contact points, increasing the overall current carrying capacity while maintaining the automated ultrasonic bonding process.
Solution Approach 2:
Multiple bonding contacts are combined into a single contact element structure that functions as one integrated component. The parallel arrangement of multiple bonding contacts within one element provides both the automation benefits of wire bonding and the enhanced current carrying capacity of multiple contact points.
2Reliability
If multiple bonding contacts are attached in parallel to increase current carrying capacity, then current carrying capacity is improved, but space requirements increase due to wider ultrasonic sonotrodes
Solution Approach 1:
Multiple bonding contacts are nested within a single contact element structure, allowing them to be arranged in parallel without requiring proportionally more space. The nested configuration enables compact arrangement of multiple contacts, reducing the overall space requirements compared to separate contact elements.
3Ease of manufacture
If metal brackets with small openings are used for soldering, then ease of manufacture is improved, but current carrying capacity is reduced in dense arrangements
Solution Approach 1:
The contact element incorporates elastic deformation capability, allowing the bonding contacts to flex and adapt during assembly. This dynamic property enables the contact element to maintain reliable electrical connection and high current carrying capacity even in dense arrangements where precise alignment is challenging, while remaining easy to manufacture.
4Area of stationary object
If blunt clip ends are used to create space-saving arrangements, then space requirements are reduced, but reliability decreases due to high current densities and shearing forces
Solution Approach 1:
The contact element features localized structural variations: the bonding contacts have specific geometries optimized for their function, with rounded or enlarged contact surfaces at critical locations. This local quality enhancement reduces current density concentrations and increases resistance to shearing forces at key points, maintaining reliability in compact designs.
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 design achieves high current-carrying capacity with minimized space requirements, improved reliability, and simplified handling, ensuring effective electrical connections in dense arrangements while reducing assembly complexity and costs.
Implementation Method 1
at least two contact elements (1), each having a first and a second projection (5, 6), which are electrically connected to a contact surface of the at least one power semiconductor component (8) or a contact surface of the carrier (9)
Implementation Method 2
The approaches of the contact elements are designed such that the first approach of one contact element is at least partially surrounded circumferentially by the second attachment of the other contact element, which creates a particularly space-saving electrical connection between two contact elements in each case and a contact point on the power semiconductor component or the carrier, it being possible for the electrical connection to be produced by means of soft soldering
Data Source
Figure 1~4
Figure 5~7
Figure 8~10
AI summary
The invention relates to a power semiconductor module with a carrier 9 having several electrical contact surfaces, at least one power semiconductor component 8 arranged on the carrier 9, and at least two contact elements 1, each having a first and a second projection 5, 6 that are electrically connected to a contact surface of the at least one power semiconductor component 8 or a contact surface of the carrier. The contact elements 1 are designed such that, at a contact surface of the power semiconductor component 8 or the carrier, the first projection 5 of one contact element is at least partially enclosed circumferentially by the second projection 6 of the other contact element. This creates a particularly space-saving electrical connection between each pair of contact elements 1 and a contact point of the power semiconductor component or the carrier, and the electrical connection can be made by soft soldering.The close proximity of the two ends of the contact elements results in a high current-carrying capacity. Handling is simplified because the ends of the contact elements self-align before the electrical connection is made. Furthermore, this eliminates the need for an additional solder preform, which would otherwise be required if the two ends of the contact elements overlapped.