Terminal Wire Connection Using Segmented Hardness for Substrates

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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 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 then cut off, forming a terminal element, utilizing a sonotrode and cutting tool to ensure a swift, reliable, and cost-effective connection.

Engineering Contradictions & Design Principles

VSEngineering 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

Engineering Contradiction:
Improveconnection stabilityVSAvoidconnection speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The terminal element is divided into multiple sections with different hardness properties along its length. The first section has lower hardness for easy welding to the substrate, while the second section has higher hardness for structural strength and cutting resistance. This segmentation allows the connection process to be both rapid and reliable without requiring complex multi-step procedures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the terminal element are assigned different material properties (hardness) to fulfill different functional requirements. The first section near the substrate connection point has optimized hardness for welding, while the second section extending outward has higher hardness for mechanical strength. This local differentiation resolves the contradiction between easy connection and overall reliability.

Inventive Principle:
Principle #3Local quality

2Reliability

If traditional connection methods are used, then stable connection is achieved, but the housing space required increases

Engineering Contradiction:
Improveconnection stabilityVSAvoidhousing space
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The terminal element uses a segmented structure where a small first section with lower hardness provides the welding interface to the substrate, while a longer second section with higher hardness extends outward. This allows the critical connection function to be achieved in a compact space while maintaining the necessary mechanical strength and electrical conductivity throughout the terminal element.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The terminal element functions as a composite structure with sections of different hardness properties, combining the benefits of soft material (easy welding, good electrical contact) and hard material (structural strength, space efficiency) within a single integrated component, thereby reducing overall housing space requirements.

Inventive Principle:
Principle #40Composite materials

3Reliability

If traditional connection methods are used, then reliable connection is achieved, but manufacturing cost increases

Engineering Contradiction:
Improveconnection stabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The terminal element's segmented hardness structure enables a simplified manufacturing process where a single welding operation creates a reliable connection without requiring multiple steps (such as separate soldering, sintering, or welding procedures). This reduces manufacturing time, equipment requirements, and labor costs while maintaining connection reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By controlling the hardness parameter along the length of the terminal element, the invention optimizes the welding process to require less energy and time while achieving the same or better connection reliability. The lower hardness of the first section facilitates easier welding, reducing manufacturing cost, while the higher hardness of the second section maintains overall structural integrity.

Inventive Principle:
Principle #35Parameter changes

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 stable, space-saving, and cost-effective connection of terminal elements to semiconductor substrates, ensuring durability and ease of assembly.

Implementation Method 1

welding the first end of the continuous wire to a substrate by means of the sonotrode

Methodology Applied
Scientific EffectUltrasonic welding: Ultrasonic Vibration

Data Source

PatentEP4607586A1Method and system for connecting a terminal element to a substrate
Publication Date: 2025.08.27 INFINEON TECHNOLOGIES AG
  • EP4607586A1 patent drawingFigure 1~2
  • EP4607586A1 patent drawingFigure 3~6
  • EP4607586A1 patent drawingFigure 7A~7E

AI summary

A method comprises feeding a continuous wire comprising 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 by means of the sonotrode, and cutting off a first segment from the continuous wire, the first segment comprising a first section comprising the first end, and a second section directly adjoining and extending from the first section, wherein at least during the step of welding 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.