Controlled Transient Cavitation for Uniform Substrate Cleaning
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Solution Overview
Problem
Current methods for controlling transient cavitation in liquids, such as those used in substrate cleaning, result in non-uniform particle removal and potential substrate damage due to uncontrolled bubble collapse, with gasified liquids offering higher efficiency but also risks of damage.
Innovation Solution
Creating a range of bubble sizes in a liquid and adjusting the acoustic field characteristics to control transient cavitation, using techniques like gas dissolution, injection, pressure cycles, and surfactants, to achieve uniform cleaning while minimizing substrate damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gasified liquid is used to enhance particle removal efficiency, then cleaning efficiency is improved, but substrate damage risk increases due to uncontrolled bubble collapse
Solution Approach 1:
The patent applies parameter changes by controlling bubble size distribution through gas dissolution, injection, pressure cycles, and surfactants, while adjusting acoustic field characteristics to achieve controlled transient cavitation that removes particles efficiently without damaging the substrate
Solution Approach 2:
The patent implements dynamics by creating a range of bubble sizes that can be adjusted and controlled dynamically through various techniques, allowing the system to adapt bubble characteristics to achieve uniform cleaning while minimizing damage
2Productivity
If transient cavitation is applied for particle removal, then cleaning effectiveness is improved, but uniformity of cleaning is reduced due to non-uniform bubble collapse
Solution Approach 1:
The patent uses parameter changes by establishing specific bubble size distributions and acoustic field characteristics that promote uniform transient cavitation across the substrate surface, achieving both effective particle removal and uniform cleaning
Solution Approach 2:
The patent applies local quality by creating controlled bubble collapse patterns that distribute cleaning action uniformly across different areas of the substrate, ensuring consistent particle removal throughout
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 enables uniform particle removal from substrates with controlled transient cavitation, reducing the risk of substrate damage and improving cleaning efficiency by optimizing bubble size distribution and acoustic field parameters.
Implementation Method 1
Transient cavitation is applied in a large number of technical fields. For example, in sonochemistry, bubbles collapsing in an ultrasonic field have a catalytic effect on chemical reactions.
Implementation Method 2
after the cleaning process, particle removal efficiency is determined. FIG. 2 is a graph that illustrates SL signals that are plotted for gasified and degassed liquids. In gasified liquids, SL signals, generated by collapsing bubbles, can be detected
Implementation Method 3
creating gas bubbles having a range of bubble sizes in a liquid... using techniques like gas dissolution, injection, pressure cycles, and surfactants
Data Source
AI summary
Methods and apparatus for creating and controlling transient cavitation are disclosed. An example method includes selecting a range of bubble sizes to be created in a liquid and selecting characteristics for an acoustic field to be applied to the liquid. The method further includes creating gas bubbles of the selected range of bubble sizes in the liquid, creating an acoustic field with the selected characteristics and subjecting the liquid to the acoustic field. In the example method, at least one of the range of bubble sizes and the characteristics of the acoustic field is selected in correspondence with the other so as to control transient cavitation in the liquid for the selected range of bubble sizes. Particularly, the methods and apparatus may be used for the cleaning of a surface, such as a semiconductor substrate.