Substrate Cleaning Layout to Cut Liquid Use and Cross-Surface Flow
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Solution Overview
Problem
Current substrate cleaning devices require a large amount of cleaning liquid to clean both surfaces of a substrate, leading to increased costs and waste, as the liquid often flows from the upper surface to the lower surface, necessitating back rinsing to prevent contamination.
Innovation Solution
A substrate cleaning device that uses a first substrate holder to hold the substrate horizontally and a cleaning brush to clean the lower surface center region without rotation, minimizing liquid flow to the upper surface, and optionally includes a second holder for rotating the substrate to clean the upper and outer lower surface regions with the same liquid as back rinse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If back rinse is performed to prevent cleaning liquid from flowing to the other surface, then the upper surface peripheral portion is protected from contamination, but a large amount of cleaning liquid is required
Solution Approach 1:
The substrate surface is divided into an upper surface and a lower surface, and cleaning is performed separately for each surface. The cleaning liquid is supplied only to the lower surface, and the cleaning brush cleans only the lower surface, preventing the need for back rinse and reducing cleaning liquid consumption.
Solution Approach 2:
The harmful factor (cleaning liquid flowing to the upper surface) is eliminated by extracting the cleaning liquid supply to only the lower surface. The cleaning brush is also positioned to contact only the lower surface, thereby preventing contamination of the upper surface without requiring additional back rinse liquid.
2Ease of operation
If the substrate is rotated during cleaning, then the cleaning liquid can be distributed over the surface, but the cleaning liquid flows from the outer peripheral end to the other surface causing contamination
Solution Approach 1:
The substrate rotation is eliminated, and the cleaning brush is moved in a reciprocating motion instead. This extraction of rotational motion prevents the cleaning liquid from flowing to the upper surface through the outer peripheral end, thereby preventing contamination while still achieving effective cleaning liquid distribution.
Solution Approach 2:
Instead of rotating the substrate to distribute cleaning liquid, the cleaning brush itself is moved in a reciprocating motion to achieve cleaning liquid distribution. This inverted approach eliminates the harmful liquid flow to the upper surface while maintaining effective cleaning liquid distribution.
3Reliability
If cleaning liquid is supplied to prevent back flow, then the other surface is protected from contamination, but the cost and waste increase
Solution Approach 1:
The need for back rinse liquid supply is eliminated by extracting the harmful factor (cleaning liquid flow to the upper surface) through non-rotational cleaning. Since the substrate is not rotated and the cleaning brush contacts only the lower surface, no back rinse is needed, reducing both cost and waste liquid.
Solution Approach 2:
The potential harm of cleaning liquid flowing to the upper surface is converted into a benefit by designing a cleaning system that prevents this flow from occurring in the first place. The non-rotational cleaning with brush-only contact transforms a potential contamination risk into a contamination-free process without requiring additional protective liquid supply.
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 reduces the overall amount of cleaning liquid needed by preventing liquid flow between surfaces and integrating back rinsing into the cleaning process, thereby minimizing waste and costs.
Implementation Method 1
a cleaning brush configured to come into contact with the lower surface of the substrate... the cleaning brush wetted with a cleaning liquid moves on a lower-surface center region of the substrate
Implementation Method 2
the cleaning brush is pressed against the lower surface of the substrate held by the first substrate holder and move the cleaning brush relative to the substrate
Data Source
AI summary
A substrate cleaning device includes an upper holding device. The upper holding device holds a substrate in a horizontal attitude without rotating the substrate, while being in contact with an outer peripheral end of the substrate. A lower-surface brush wetted with a cleaning liquid is pressed against a lower-surface center region of the substrate held by the upper holding device. In this state, the lower-surface brush is rotated or moved with respect to the lower-surface center region of the substrate. Thus, the lower-surface center region of the substrate is cleaned.