Flexible Wedge-Bonded Fine-Wire Structures for Power Modules
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Solution Overview
Problem
Existing electrical connecting elements in electronic modules, particularly in power electronics, face challenges with rigidity and reduced flexibility due to the use of thick bonding wires and bonding ribbons made of solid metal material, which limits their ability to form complex loop shapes and increases mechanical stress.
Innovation Solution
Employing wedge-wedge-bonded structures made from fine metal wire assemblies, such as warp-knitted, weft-knitted, woven, or braided ribbons, cables, or tubular networks, which are not made of solid metal material, allowing for increased flexibility and complex loop formation without the use of additional attachment devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If thick bonding wires and bonding ribbons made of solid metal material are used, then the electrical connection can handle high currents, but the rigidity increases and flexibility is reduced
Solution Approach 1:
The patent applies segmentation by dividing the solid metal bonding wire into multiple fine metal wires (e.g., 7 to 49 individual wires). This segmented structure maintains the required cross-sectional area for high current handling while introducing flexibility through the multi-wire construction, allowing the bonding wire to form complex loop shapes without excessive rigidity
Solution Approach 2:
The patent uses composite materials by combining multiple fine metal wires into a bundled structure with a common coating. This composite construction provides both the electrical conductivity needed for high currents and the mechanical flexibility required for complex bonding geometries, resolving the contradiction between power handling and ease of operation
2Power
If the cross-section of bonding wires is increased to handle high currents, then the current carrying capacity improves, but the rigidity increases and flexibility decreases
Solution Approach 1:
The patent segments the thick bonding wire into multiple fine wires bundled together. This allows the overall cross-section to be large enough for high current carrying capacity while the individual fine wires maintain flexibility, enabling the formation of complex loop shapes required in power module assembly
Solution Approach 2:
The patent applies a common coating (flexible shell) around the bundle of fine metal wires. This coating protects the individual wires while maintaining the flexibility of the overall structure, allowing complex loop formation while preserving the large cross-sectional area needed for high current capacity
3Reliability
If additional attachment devices are used to connect bonding wires, then the connection reliability improves, but the device complexity increases
Solution Approach 1:
The patent merges the bonding wire structure with the attachment function by using the fine wire bundle itself as the connecting element. The wedge-shaped bonding areas at the ends of the fine wire bundle directly attach to the bonding pads, eliminating the need for separate attachment devices and reducing overall device complexity while maintaining connection reliability
Solution Approach 2:
The fine metal wire bundle serves multiple functions simultaneously: it provides electrical connection, mechanical attachment, and structural support. This multi-functionality eliminates the need for additional specialized components, reducing device complexity while ensuring reliable connections
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 wedge-wedge-bonded structures provide enhanced flexibility, enabling more complex loop shapes and reduced mechanical stress, thereby improving the service life and performance of electronic modules.
Implementation Method 1
wedge-wedge-bonded structures that are not made of solid metal material as electrical connecting elements
Data Source
AI summary
An electronic module comprising one or more assemblies each consisting of a first electronic component with a first contact surface with a first end, wedge-bonded on this first contact surface, and a second electronic component with a second contact surface with a second end, wedge-bonded on this second contact surface, wherein the originally free structure not made of solid metal material is a structure (i) in the form of a ribbon made from warp-knitted, weft-knitted, woven or braided fine metal wire and having a cross-sectional area within a range of 25,000 to 800,000 μm2, or (ii) in the form of a cable made from stranded fine metal wire and having a cross-sectional area within a range of 8,000 to 600,000 μm2, or (iii) in the form of a tube made from circular-warp-knitted or circular-weft-knitted fine metal wire and having a cross-sectional area within a range of 8,000 to 600,000 μm2.