Terminal Wire Bonding With Alternating Hardness Segments
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Solution Overview
Problem
Existing methods for connecting terminal elements to semiconductor substrates in power semiconductor modules are cumbersome, costly, and space-consuming, and do not provide a stable, reliable, and efficient connection.
Innovation Solution
A method and system using a continuous wire with alternating soft and hard segments, where the hard segments are welded to the substrate and cut off to form terminal elements, utilizing a sonotrode and cutting tool for efficient attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional soldering, sintering or welding techniques are used to connect terminal elements to substrate, then reliable electrical connection is achieved, but the process becomes time-consuming, costly and space-consuming
Solution Approach 1:
The continuous wire is segmented into alternating soft segments and hard segments, where soft segments enable reliable welding to the substrate while hard segments provide structural support and facilitate quick cutting. This segmentation allows the connection process to be both reliable and efficient, resolving the contradiction between connection stability and connection speed.
Solution Approach 2:
Different segments of the wire have different local qualities (hardness), with soft segments at welding positions for reliable attachment and hard segments elsewhere for structural integrity and ease of cutting. This local differentiation enables the wire to simultaneously achieve reliable connection and fast processing.
2Reliability
If traditional connection methods are used, then stable connection is achieved, but the process becomes complex and costly
Solution Approach 1:
The wire is pre-segmented into soft and hard sections, which simplifies the overall process by eliminating the need for complex multi-step connection procedures. The segmentation is done in advance, reducing on-site complexity while maintaining connection reliability.
Solution Approach 2:
The hardness parameter of the wire is changed along its length to create soft and hard segments. This parameter variation enables different functions in different regions without requiring complex device structures or processes.
3Ease of manufacture
If uniform hardness wire is used throughout, then manufacturing simplicity is maintained, but welding reliability and cutting efficiency cannot be optimized simultaneously
Solution Approach 1:
The wire has different local qualities with soft segments for welding and hard segments for structural support. This local differentiation optimizes both welding reliability and cutting efficiency while maintaining relatively simple manufacturing through continuous wire drawing with varying properties.
Solution Approach 2:
The wire can be viewed as a composite structure with different material properties (soft and hard segments) along its length. This composite approach enables simultaneous optimization of welding and cutting functions without requiring entirely separate components.
4Reliability
If soft wire is used for welding, then welding reliability improves, but structural strength and cutting efficiency decrease
Solution Approach 1:
The wire is segmented into soft welding zones and hard structural zones. The soft segments provide reliable welding to the substrate while the hard segments maintain structural strength and enable efficient cutting, thus resolving the contradiction between welding reliability and structural strength.
Solution Approach 2:
Different parts of the wire have different local qualities: soft at welding positions for reliable attachment, hard elsewhere for structural integrity. This local quality differentiation allows the wire to simultaneously achieve welding reliability and structural strength.
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 method provides a swift, reliable, and cost-effective connection of terminal elements to the substrate, ensuring stability and space efficiency by using a continuous wire with alternating hard and soft segments.
Implementation Method 1
welding the first end of the continuous wire to a substrate by means of the sonotrode
Data Source
AI summary
A method includes: feeding a continuous wire, including a plurality of segments arranged successively to form the continuous wire, into a first end of a channel and further through the channel formed in a sonotrode of a welding tool until a first end of the continuous wire protrudes from a second end of the channel opposite the first end of the channel; welding the first end of the continuous wire to a substrate via the sonotrode; and cutting off a first segment from the continuous wire, the first segment including a first section having the first end, and a second section directly adjoining and extending from the first section. At least during the welding of the first end of the continuous wire to the substrate, a hardness of the second section is greater than a hardness of the first section.