Vibrator Unit Resonance Mismatch for EUV Droplet Stability
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Solution Overview
Problem
In EUV light generation systems, the reduction of nozzle diameter to produce finer droplets destabilizes the droplet generation cycle due to increased vibration frequency, leading to vibration noise and instability, as typical piezoelectric elements exceed their resonance frequency when generating high-frequency signals.
Innovation Solution
The use of a composite piezoelectric element with a resonance frequency of 4 MHz or higher, combined with a vibration transmission member and retention member designed to have mode-1 natural frequencies less than half the electrical signal frequency, reduces vibration noise by ensuring the frequency of electrical signals is below the resonance frequency of the piezoelectric element and minimizing resonance amplification in the vibration transfer path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the nozzle diameter is reduced to produce finer droplets, then the droplet size is improved, but the droplet generation cycle becomes unstable due to increased vibration frequency
Solution Approach 1:
The patent changes the resonance frequency parameter of the piezoelectric element by selecting materials and designs that achieve 4 MHz or higher resonance frequency. This parameter change allows the system to operate at the required high frequencies for fine droplet generation without exceeding the element's resonance frequency, thereby maintaining stability while achieving finer droplet sizes.
2Productivity
If the electrical signal frequency is increased to match the higher vibration frequency, then the droplet generation speed is improved, but vibration noise increases and destabilizes the system
Solution Approach 1:
The patent utilizes mechanical vibration principles by designing the piezoelectric element to resonate at a specific high frequency (4 MHz or higher). By operating the element at or below its resonance frequency, the system achieves efficient droplet generation through controlled mechanical vibration while avoiding the harmful effects of exceeding resonance, which would cause excessive vibration noise and instability.
3Device complexity
If a typical piezoelectric element is used, then the device complexity is kept simple, but the element exceeds its resonance frequency when generating high-frequency signals, causing instability
Solution Approach 1:
The patent employs composite material principles by using a piezoelectric element composed of multiple layers or composite structures that achieve the required high resonance frequency of 4 MHz or higher. This composite approach allows the element to maintain structural simplicity while achieving the necessary high-frequency performance and stability that single-material elements cannot provide.
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 configuration stabilizes the droplet generation cycle by reducing vibration noise and maintaining efficient droplet formation even at higher frequencies, ensuring consistent and precise droplet size and cycle production.
Implementation Method 1
a vibration element (314) configured to vibrate in response to an external electrical signal having a predetermined frequency
Implementation Method 2
a vibration transmission member (311, 331)... The vibration element (314) may be in contact with the vibration transmission member and vibrate
Implementation Method 3
A resonance frequency of the vibration element may be different from the predetermined frequency of the electrical signal... A mode-1 natural frequency of the vibration transmission member may be different from the resonance frequency of the vibration element
Data Source
AI summary
A vibrator unit may be configured to vibrate a target material in a target channel and include a vibration element configured to vibrate in response to an external electrical signal having a predetermined frequency. A resonance frequency of the vibration element may be different from the predetermined frequency of the electrical signal. A vibrator unit may include a vibration transmission member in contact with the first member including the target channel in interior; and a vibration element that is in contact with the vibration transmission member. A mode-1 natural frequency of the vibration transmission member may be different from a resonance frequency of the vibration element.