Substrate Freeze Cleaning with Feedback-Controlled Ice Melting
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Solution Overview
Problem
Existing freeze cleaning technologies for substrates experience fluctuations in contaminant removal rates due to inconsistent timing of ice film melting, leading to unstable contaminant removal across different substrates.
Innovation Solution
A substrate treatment device with a controller that detects the start of freezing in a supercooled liquid state and controls the thawing process after a predetermined interval, stabilizing the timing of ice film melting by using a detector to ensure consistent contaminant removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If time management is used to control the melting timing of the ice film, then the process is simple to operate, but the contaminant removal rate fluctuates between substrates
Solution Approach 1:
The patent employs a detector to monitor the actual temperature of the ice film in real-time and provides feedback to the controller. The controller adjusts the thawing process based on this feedback, ensuring that the ice film melts at the optimal moment for contaminant removal. This closed-loop control system eliminates the fluctuations in contaminant removal rate that occur with simple time management, while maintaining ease of operation through automated control.
2Strength
If the ice film is melted too early, then the substrate is protected from cracking, but the contaminant removal rate decreases
Solution Approach 1:
The patent dynamically changes the temperature parameter of the ice film by controlling the thawing process. The detector monitors the ice film temperature, and the controller adjusts the heating power to achieve the precise temperature at which the ice film becomes sufficiently soft for contaminant removal while maintaining substrate integrity. This parameter optimization resolves the contradiction between early melting (protecting substrate) and delayed melting (improving contaminant removal).
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 device achieves stable and consistent contaminant removal rates by controlling the thawing process based on detected freezing initiation, reducing fluctuations and minimizing substrate damage from cracking.
Implementation Method 1
a process (a supercooling process) of causing the water film to reach a supercooled state
Implementation Method 2
The water film is frozen by the cooling gas supplied to the substrate. When the water film freezes to form an ice film, contaminants such as particles and the like are detached from the surface of the substrate by being incorporated into the ice film
Implementation Method 3
the ice film is melted by supplying purified water to the ice film; and the contaminants are removed from the surface of the substrate together with the purified water
Data Source
AI summary
A substrate treatment device includes a placement platform rotating a substrate, a cooling part supplying a cooling gas to a space between the placement platform and the substrate, a liquid supplier supplying a liquid to a surface of the substrate opposite to the placement platform side, a detector that is above the surface of the substrate and detects a freezing start of the liquid, and a controller controlling the substrate rotation, the cooling gas supply, and the liquid supply. The controller controls at least one of the substrate rotation, the cooling gas flow rate, or the liquid supply rate, and causes the liquid on the substrate surface to reach a supercooled state; and when determining based on a signal from the detector that the freezing of the supercooled liquid has started, the controller starts thawing the frozen liquid after a prescribed interval has elapsed from the freezing start of the liquid.