Ultrasonic Welding Alignment Using Sonotrode Imprint Feedback

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Solution Overview

Problem

Current automated ultrasonic welding methods for semiconductor assemblies require significant effort to correct sonotrode positional deviations, especially after sonotrode changes, due to external forces or manufacturing tolerances, which can lead to incomplete welds and inefficiencies in the welding process.

Innovation Solution

A method utilizing a camera device with image processing to determine and compensate for sonotrode positional deviations by using a reference impression carrier, allowing for real-time adjustment of the sonotrode's position relative to the contact partners, enabling accurate alignment without the need for sonotrode replacement or re-clamping, and integrating this compensation into the feed path for continuous welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a camera device with image processing is used to detect sonotrode positional deviations, then positioning precision is improved, but device complexity increases

Engineering Contradiction:
Improvesonotrode positioning precisionVSAvoidpositioning system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses a camera device to create an optical copy (image) of the sonotrode impression on the reference carrier, replacing complex mechanical measurement systems. The image processing device then analyzes this optical copy to determine positional deviations, achieving high precision measurement without complex mechanical structures.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces traditional mechanical measurement systems with an optical system consisting of a camera and image processing device. This substitution eliminates the need for complex mechanical contact probes or laser interferometers, reducing device complexity while maintaining or improving measurement precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If sonotrode positional deviations are corrected by replacing or re-clamping the sonotrode, then positioning accuracy is improved, but productivity decreases

Engineering Contradiction:
Improvesonotrode positioning accuracyVSAvoidwelding production efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent implements a feedback mechanism where the camera device continuously monitors the sonotrode impression position on the reference carrier, and the positioning device automatically adjusts the sonotrode position based on detected deviations. This closed-loop feedback system maintains positioning accuracy without requiring manual intervention or sonotrode replacement, thus preserving productivity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The positioning system performs self-correction by automatically detecting and compensating for sonotrode positional deviations during the welding process. The system adjusts the sonotrode position in real-time without requiring external intervention, operator skill, or sonotrode replacement, enabling continuous production at full speed.

Inventive Principle:
Principle #25Self-service

3Reliability

If the sonotrode is frequently replaced or re-clamped to correct positioning errors, then welding quality is improved, but loss of time increases

Engineering Contradiction:
Improvewelding quality consistencyVSAvoidsonotrode replacement time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary positioning correction by detecting sonotrode impression deviations on the reference carrier and adjusting the sonotrode position before actual welding begins. This preliminary action prevents welding quality issues from developing, eliminating the need for time-consuming sonotrode replacements during production.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The real-time feedback from the camera and image processing system allows continuous monitoring and adjustment of sonotrode position, ensuring welding quality consistency without interruption. The system detects and corrects deviations automatically, preventing the accumulation of errors that would otherwise require sonotrode replacement.

Inventive Principle:
Principle #23Feedback

4Measurement precision

If manual adjustment of sonotrode clamping is performed to correct positional deviations, then positioning precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvesonotrode position precisionVSAvoidsonotrode adjustment ease
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces manual mechanical adjustment with an automated optical measurement and control system. The camera device captures the sonotrode impression position, the image processing device calculates deviations, and the positioning device automatically adjusts the sonotrode position, eliminating the need for manual intervention and its associated complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The positioning system performs self-adjustment by automatically detecting sonotrode positional deviations and correcting them without operator intervention. The system uses the reference carrier and camera feedback to autonomously maintain precise positioning, making the operation as easy as initiating the automated cycle.

Inventive Principle:
Principle #25Self-service

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 reduces the effort required for sonotrode error correction, ensures accurate positioning, and maintains consistent welding quality by accounting for deviations in real-time, thereby improving the efficiency and reliability of the ultrasonic welding process.

Implementation Method 1

is subjected to ultrasonic vibrations

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentEP3600752B1Method for producing a welded assembly
Publication Date: 2024.07.10 SCHUNK SONOSYST GMBH
  • EP3600752B1 patent drawingFigure 1~4
  • EP3600752B1 patent drawingFigure 5~9

AI summary

The invention relates to a method for producing a welded assembly (14) with a plurality of welded connections between first contact partners (11) of a contact substrate (10) and second contact partners (13) of a component placement unit preferably configured as a semiconductor assembly (12), in which, for the relative positioning of the first and second contact partners (11, 13) in a welding position, the contact partners (11, 13) are arranged in an overlapping position and, for positioning a sonotrode (15) in individual welding positions, the sonotrode (15) is brought into an overlapping position with the second contact partner (13) by means of a positioning device (17) and, for producing a welded connection, is lowered onto the second contact partner (13) into a welding contact position and is subjected to ultrasonic vibrations, wherein the positioning of the sonotrode (15) with respect to the second contact partner (13) is performed by means of a camera device provided with an image processing device in such a way that the positioning of the sonotrode (15) with respect to the second contact partner (13) takes place on the basis of a determination of a positional deviation ΔxSA, ΔySA of a sonotrode imprint of a sonotrode working area of the sonotrode (15) that is produced by the welding operation on a reference imprint carrier.