Piezoelectric Shear Actuator Bonding Transducer

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Solution Overview

Problem

Conventional bonding devices have limited dynamic properties due to the orientation of the transducer, which restricts positioning speed and accuracy, and result in potential damage to the bonding wire or substrate during the bonding process.

Innovation Solution

The introduction of a piezoelectric shear actuator that excites shearing vibrations, allowing for a more compact and lightweight transducer design with improved dynamic properties, enabling faster and more precise positioning of the bondhead, and simplifying electrical control by using a single actuator with electrodes offset 90° to the polarization direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the transducer is oriented transversely to the axis of rotation of the bondhead, then the bonding device structure is stable and proven, but the positioning speed and dynamics are limited

Engineering Contradiction:
Improvepositioning speedVSAvoidtransducer orientation complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent inverts the conventional transducer orientation by aligning it parallel to the bondhead rotation axis instead of transversely. This inversion enables the use of shear actuators that generate ultrasonic vibrations through shearing movements, significantly improving positioning speed while maintaining structural stability.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent replaces conventional longitudinal piezoelectric actuators with shear actuators that operate on different mechanical principles. The shear actuators generate ultrasonic vibrations through shearing movements rather than longitudinal expansion, enabling faster positioning and improved dynamics.

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

2Weight of moving object

If multiple piezoelectric actuators are used to generate ultrasonic vibration, then the bonding function is achieved, but the device weight increases

Engineering Contradiction:
Improvetransducer weightVSAvoidbonding reliability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent merges the functions of multiple piezoelectric actuators into a single shear actuator. The shear actuator generates ultrasonic vibrations through shearing movements that simultaneously achieve both bonding and positioning functions, reducing weight while maintaining reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shear actuator serves multiple functions: it generates ultrasonic vibrations for bonding, provides positioning capability, and reduces overall device weight. This multi-functionality eliminates the need for separate actuators for different functions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If the transducer weight is reduced to minimize impact impulse, then damage to bonding wire or substrate is avoided, but positioning accuracy may be compromised

Engineering Contradiction:
Improveimpact impulseVSAvoidpositioning accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent changes the operational parameters of the piezoelectric actuator by using shear mode vibration instead of longitudinal mode. This parameter change enables the generation of ultrasonic vibrations with reduced impact impulse while maintaining positioning accuracy through precise control of the shearing movements.

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If conventional piezoelectric actuators with longitudinal expansion are used, then the bonding function is achieved, but the device size and complexity increase

Engineering Contradiction:
Improveactuator structure complexityVSAvoidultrasonic vibration generation
Core Design Contradiction:
Device complexityVSPower

Solution Approach 1:

The patent replaces the conventional longitudinal expansion mechanism with a shear actuator that generates ultrasonic vibrations through shearing movements. This substitution simplifies the actuator structure, reduces the number of components, and maintains effective power transmission for ultrasonic vibration generation.

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

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 solution enhances the dynamic performance of the bonding device, reduces weight, and increases robustness, allowing for higher vibration amplitudes and improved miniaturization, while maintaining good positioning accuracy and reducing the risk of damage to the bonding wire or substrate.

Implementation Method 1

a piezoelectric actuator (5) is provided between the fastening section (6) and the tool holder (3)

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the piezoelectric actuator (5) as a result of the excitation causes a shearing movement as an ultrasonic natural oscillation in a direction through the polarization direction and the Field direction formed shear plane performs

Methodology Applied
Scientific EffectShear vibration excitation: Ultrasonic Vibration

Data Source

PatentEP3166744B1Device for establishing a bonding connection
Publication Date: 2018.09.12 HESSE
  • EP3166744B1 patent drawingFigure 1
  • EP3166744B1 patent drawingFigure 2
  • EP3166744B1 patent drawingFigure 3

AI summary

The invention relates to a device for establishing a bonding connection, comprising a bonding head mounted so as to rotate about an axis of rotation, and a transducer (1) mounted on the bonding head, where the transducer (1) has a piezo actuator (5) for generating ultrasonic vibration, in particular a natural ultrasonic vibration, a fastening section (6) for attaching the transducer (1) to the bonding head and a tool holder (3) for a bonding tool (2), a longitudinal extension (8) of the transducer (1) and/or an extension of the same in the direction of an axis of a minimum inertial moment runs parallel to the axis of rotation of the bonding head, electrodes (20) being provided on the piezo actuator (5) in such a way that the piezo actuator (5) can be excited by an electric field in a field direction (10) transverse to a polarisation direction (9) of the piezo actuator, and as a result of the excitation and of the connection of the piezo actuator (5) to the fastening section (6) and to the tool holder (3), the piezo actuator (5) carries out a shearing motion in a shearing plane (18) formed by the polarisation direction (9) and by the field direction (10).