Substrate treatment device
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Solution Overview
Problem
The existing freeze-cleaning methods for substrates, such as semiconductor wafers and photolithography masks, face challenges with static electricity generation due to low conductivity of cleaning liquids, leading to potential electrostatic breakdown and damage to the substrate or patterns, while conductive liquids used to mitigate this issue result in lower contamination removal ratios.
Innovation Solution
A substrate treatment device that employs a conductive liquid for the preliminary process, followed by a low-conductivity liquid for forming and freezing a film on the substrate, utilizing controlled rotation and gas flow to manage static electricity and enhance contamination removal, with the conductive liquid also serving in the thawing process to maintain high removal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pure water (low conductivity liquid) is used for freeze-cleaning, then contamination removal ratio is improved, but static electricity is easily generated causing electrostatic breakdown and substrate damage
Solution Approach 1:
A conductive liquid is supplied to the substrate surface before the pure water supply to create a conductive layer that prevents static electricity generation during the subsequent pure water freeze-cleaning process
Solution Approach 2:
A conductive liquid is introduced as an intermediary substance between the pure water and the substrate surface, allowing the pure water to maintain its low conductivity for effective freeze-cleaning while the conductive liquid prevents static electricity accumulation
2Reliability
If conductive liquid is used to suppress static electricity, then electrostatic breakdown is prevented, but contamination removal ratio decreases
Solution Approach 1:
The conductive liquid is supplied in advance to prepare the substrate surface, and then pure water is supplied for the actual freeze-cleaning process, separating the electrostatic protection function from the contamination removal function
Solution Approach 2:
The cleaning process is divided into distinct stages with different liquids serving different functions: conductive liquid for electrostatic protection and pure water for contamination removal, with each liquid optimized for its specific purpose
3Productivity
If pure water is supplied to rotating substrate, then contamination removal is effective, but static electricity generation increases due to friction and rotation
Solution Approach 1:
The conductive liquid is supplied to the substrate surface before and during the pure water supply phase, creating a protective conductive layer that prevents static electricity generation from the friction between pure water and the rotating substrate surface
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 effectively suppresses static electricity generation while maintaining a high contamination removal ratio, even with low-conductivity liquids, by using a conductive liquid in the preliminary and thawing stages to ensure uniform temperature and prevent frost formation, thereby improving the operational efficiency of the freeze-cleaning process.
Implementation Method 1
The water film is frozen by the cooling gas supplied to the substrate. When the water film freezes and an ice film is formed, contaminations such as particles are taken into the ice film and separated from the surface of the substrate.
Implementation Method 2
a conductive liquid supplied toward a surface of the substrate... effectively suppresses static electricity generation while maintaining a high contamination removal ratio
Data Source
AI summary
According to one embodiment, a substrate treatment device includes a placement stand configured to rotate the substrate, a cooling part configured to supply a cooling gas into a space between the placement stand and the substrate, a first liquid supplier configured to supply a first liquid on a surface of the substrate, a second liquid supplier configured to supply a second liquid on the surface, and a controller controlling rotation of the substrate, supply of the cooling gas, the first and second liquids. The controller performs a preliminary process of supplying the second liquid on the surface, and supplying the cooling gas into the space, a liquid film forming process by supplying the first liquid toward the surface after the preliminary process, a supercooling process of the liquid film on the surface, and a freezing process of at least a part of the liquid film on the surface.