Substrate Processing Liquid Dissolved Oxygen Control
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Solution Overview
Problem
Existing substrate processing methods face challenges in maintaining stable dissolved oxygen concentrations when reusing processing liquids, as gases other than oxygen and inert gases can degrade oxygen meter precision, leading to inaccurate concentration adjustments.
Innovation Solution
A method and apparatus that measure and adjust the dissolved oxygen concentration in processing liquids by supplying a concentration adjusting gas with a higher inert gas content, and include steps to decrease unnecessary gases before re-collecting the liquid, using a combination of degassing and gas dissolving units in multiple tanks to ensure precise concentration control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If processing liquid is collected and reused to improve productivity, then substrate processing can continue without interruption, but gas other than oxygen and inert gas dissolves in the processing liquid and degrades oxygen meter detection precision
Solution Approach 1:
The patent applies preliminary action by removing unnecessary gases from the processing liquid before it is collected and reused. The gas removal unit operates in advance to eliminate interfering gases (other than oxygen and inert gas) that would otherwise dissolve in the processing liquid and degrade oxygen meter detection precision. This preliminary gas removal ensures that when the processing liquid is reused, the oxygen concentration measurements remain accurate.
2Reliability
If dissolved oxygen concentration is adjusted by supplying concentration adjusting gas to maintain stable quality, then substrate processing quality stabilizes, but gas other than concentration adjusting gas remains in the processing liquid and interferes with oxygen meter detection
Solution Approach 1:
The patent applies the extraction principle by removing unnecessary gases (gas other than oxygen and inert gas) from the processing liquid through the gas removal unit. This extraction process eliminates interfering substances that would otherwise degrade oxygen meter detection precision, while preserving the concentration adjusting gas (inert gas) that is necessary for maintaining stable dissolved oxygen concentrations and substrate processing quality.
3Extent of automation
If oxygen meter is used to detect dissolved oxygen concentration for control, then dissolved oxygen concentration can be adjusted, but detection precision is degraded by gas other than oxygen gas and inert gas
Solution Approach 1:
The patent applies the intermediary principle by introducing a gas removal unit as an intermediate treatment step between the processing liquid circulation and the oxygen meter detection. This intermediary unit removes unnecessary gases that would interfere with oxygen meter detection precision, thereby enabling accurate automated control of dissolved oxygen concentrations without the interference of other dissolved gases.
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 allows for the stabilization of substrate processing quality by minimizing measurement errors and achieving target dissolved oxygen concentrations, even when reusing processing liquids, thereby ensuring consistent substrate processing.
Implementation Method 1
a dissolved oxygen concentration measuring step of measuring a dissolved oxygen concentration of the processing liquid
Implementation Method 2
The concentration adjusting gas having the concentration of inert gas higher than that of air is supplied into the supply tank. Thus, the concentration adjusting gas is dissolved in the processing liquid in the supply tank
Implementation Method 3
an unnecessary gas decreasing step of decreasing an unnecessary gas, that is a gas other than the concentration adjusting gas and dissolved in the processing liquid in the processing liquid supplying step, from the processing liquid
Data Source
AI summary
Processing liquid is stored by a supply tank. The dissolved oxygen concentration of the processing liquid is measured. The dissolved oxygen concentration of the processing liquid in the supply tank is adjusted by supplying concentration adjusting gas having a concentration of inert gas higher than that of air into the supply tank in accordance with the dissolved oxygen concentration of the processing liquid measured. The processing liquid in the supply tank is supplied to a substrate. The processing liquid that has been supplied to the substrate is collected to the supply tank. Unnecessary gas that is a gas other than the concentration adjusting gas and dissolved in the processing liquid during the processing of the substrate is decreased from the processing liquid before the processing liquid is collected to the supply tank.