Triangular Horn Ultrasonic Transducer for Wire Bonding
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Solution Overview
Problem
Conventional ultrasonic transducers with circular or rectangular cross-sections face inefficiencies in oscillatory performance and amplification, leading to strain and impedance issues during the wire bonding process, which affect the efficiency of ultrasonic energy transmission and bonding quality.
Innovation Solution
The ultrasonic transducer features a horn with a substantially triangular cross-sectional area, allowing for improved strain distribution and reduced impedance changes through strategic clamping positions, enhancing the amplification and stiffness of the transducer, thereby increasing ultrasonic vibration amplitude and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a horn with circular or rectangular cross-section is used, then the transducer structure is simple and easy to manufacture, but the oscillatory efficiency and amplification characteristics are insufficient
Solution Approach 1:
The patent applies asymmetry by changing the horn cross-section from circular or rectangular to triangular. This asymmetric geometry creates more favorable stress distribution patterns during oscillation, improving amplification characteristics and oscillatory efficiency while maintaining manufacturability through standard machining processes.
Solution Approach 2:
The patent changes the geometric parameter of the horn cross-section from conventional circular/rectangular shapes to triangular configuration. This parameter change optimizes the stress distribution and resonance characteristics, leading to improved oscillatory efficiency and amplification without significantly complicating the manufacturing process.
2Reliability
If the transducer is clamped on the barrel to hold it at node locations, then the transducer is securely positioned, but considerable strain is caused on the horn and ultrasonic driver
Solution Approach 1:
The triangular cross-section creates asymmetric stiffness distribution around the horn perimeter. By strategically positioning clamps at specific locations (e.g., at the midpoints of the triangular sides rather than at vertices), the design achieves stable positioning while distributing clamping forces more evenly, reducing peak strains on the horn and driver.
Solution Approach 2:
The patent applies local quality by varying the clamping strategy according to the local stiffness characteristics created by the triangular cross-section. Different regions of the horn perimeter have different structural properties, and clamps are positioned to exploit these local characteristics for optimal stress distribution and minimal strain on critical components.
3Device complexity
If conventional horn geometry is used, then the device structure is straightforward, but the ultrasonic vibration amplitude at the capillary is insufficient for efficient bonding
Solution Approach 1:
The triangular cross-section creates asymmetric vibration mode shapes that concentrate ultrasonic energy more effectively at the capillary location. This geometric asymmetry enhances the amplification ratio from the driver to the bonding interface, improving bonding efficiency without adding complex multi-component structures.
Solution Approach 2:
By changing the cross-sectional geometry parameter from circular/rectangular to triangular, the patent optimizes the resonance characteristics and vibration amplitude distribution along the horn length. This single geometric parameter change achieves higher ultrasonic vibration amplitude at the capillary, directly improving bonding efficiency while maintaining structural simplicity.
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 triangular cross-sectional design results in significantly higher ultrasonic vibration amplitudes and lower impedance, leading to improved bonding efficiency, reduced heat emission, and consistent performance, while being easier to manufacture and integrate into existing systems.
Implementation Method 1
a set of piezoelectric discs comprised in the ultrasonic driver 108 is subjected to an alternating electrical signal which causes the discs to expand and contract according to the signal. Consequently, an ultrasonic wave is generated
Implementation Method 2
an ultrasonic wave is generated at the applied frequency of the electrical signal. Since the wave produced has a small amplitude, an amplifying device (in this case the horn 102) is required
Implementation Method 3
the transducer 100 undergoes continuous resonance during operation. It is hence held at node locations by using a thin web of material that connects the horn 102 to the barrel 104 at a node location of a standing ultrasonic wave within the horn 102
Data Source
AI summary
A bonding apparatus such as an ultrasonic transducer is provided that comprises an oscillation amplification device having a longitudinal axis and a substantially triangular cross-sectional area on a plane that is orthogonal to the longitudinal axis. An ultrasonic driver is coupled to the oscillation amplification device at a first position along the longitudinal axis and a bonding tool is mounted to the oscillation amplification device at a second position along the longitudinal axis spaced from the first position.