Substrate Cleaning via Dissolved Gas Concentration Control
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Solution Overview
Problem
Existing substrate cleaning methods using ultrasonic waves often result in uneven particle removal due to interference from holding members, leading to lower efficiency in certain areas of the substrate.
Innovation Solution
The method involves immersing the substrate in a cleaning liquid and generating ultrasonic waves while varying the dissolved gas concentration, either by stopping the waves temporarily or changing the concentration during their generation, using a system with separate supply pipes for liquids of different gas concentrations to achieve uniform cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ultrasonic waves are radiated from below the substrate through a holding member, then the substrate can be cleaned by ultrasonic cleaning process, but the holding member interferes with the radiation of ultrasonic waves resulting in uneven particle removal efficiency across the substrate surface
Solution Approach 1:
The patent changes the dissolved gas concentration parameter in the cleaning liquid to control the position of high particle removal efficiency areas. By adjusting this parameter, the cleaning system can compensate for the interference caused by the holding member and achieve more uniform cleaning across the substrate surface.
2Manufacturing precision
If the dissolved gas concentration of the cleaning liquid is changed to improve uniformity of particle removal, then the cleaning efficiency across the substrate surface improves, but the control system becomes more complex
Solution Approach 1:
The patent employs parameter changes by adjusting the dissolved gas concentration in the cleaning liquid to achieve uniform particle removal across the substrate. This approach addresses the technical contradiction by using a controllable parameter that can be adjusted through relatively simple means to improve cleaning uniformity without requiring overly complex control systems.
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 enhances particle removal efficiency across the entire substrate surface, allowing for more effective cleaning with simpler control systems and reduced costs.
Implementation Method 1
cleaning the substrate by generating ultrasonic waves in the cleaning liquid contained in the cleaning tank
Implementation Method 2
generating ultrasonic waves in the cleaning liquid
Data Source
AI summary
The present invention provides a substrate cleaning method capable of removing particles from the entire surface of a substrate to be processed at a high removing efficiency. In the substrate cleaning method according to the present invention, a substrate to be processed W is immersed in a cleaning liquid in a cleaning tank 12. Then, ultrasonic waves are generated in the cleaning liquid contained in the cleaning tank 12, so that the substrate to be processed W is subjected to an ultrasonic cleaning process. While the substrate to be processed is being cleaned, a dissolved gas concentration of a gas dissolved in the cleaning liquid contained in the cleaning tank is changed.