Substrate Drying End-Point Detection via Mixed-Fluid Density
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Solution Overview
Problem
Existing substrate processing technologies face challenges in accurately detecting the termination of drying and identifying abnormalities during the drying process, leading to inefficiencies and potential damage to concave-convex patterns due to surface tension and liquid-gas interface issues.
Innovation Solution
A substrate processing apparatus that uses a supercritical fluid to replace drying liquids, incorporating a discharge line with a density detector to monitor the density of the mixed fluid, allowing for precise detection of drying completion and abnormality identification through real-time density changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical detection is used to detect liquid presence in the drying part, then liquid detection capability is provided, but the detection accuracy is insufficient to accurately determine drying termination
Solution Approach 1:
The patent introduces a density detector as an intermediary device that measures the density of the fluid in the discharge line. This density measurement serves as a reliable indicator of drying completion, overcoming the insufficient accuracy of direct optical detection methods. The density detector acts as a mediator between the drying process and the control system, providing accurate real-time information about drying termination.
Solution Approach 2:
The patent replaces the optical detection system with a density-based detection system. Instead of using optical properties to detect liquid presence, the system uses density measurements of the discharged fluid to infer drying completion. This substitution provides more accurate and reliable detection information for controlling the drying process.
2Reliability
If drying is extended to ensure complete drying, then drying completeness is improved, but processing time increases and throughput decreases
Solution Approach 1:
The patent implements a feedback control system where the density detector continuously monitors the fluid density in the discharge line and provides real-time feedback to the control system. Based on this feedback, the system can dynamically adjust the drying time and initiate depressurization at the optimal moment when drying is complete, avoiding both under-drying and excessive drying. This feedback mechanism ensures drying completeness while optimizing processing time for maximum throughput.
Solution Approach 2:
The patent introduces dynamic control of the drying process based on real-time density measurements. Instead of using a fixed drying time, the system dynamically adjusts the drying duration and depressurization timing according to the actual drying state indicated by density changes. This dynamic approach allows the process to adapt to varying conditions, ensuring complete drying while minimizing processing time to enhance productivity.
3Productivity
If depressurization is initiated early to improve throughput, then productivity increases, but liquid may remain on the substrate causing pattern collapse
Solution Approach 1:
The density detector provides continuous feedback on the drying state, enabling the control system to make informed decisions about when to initiate depressurization. The system monitors density changes and only triggers depressurization when the density indicates that drying is complete, thus preventing pattern collapse while optimizing throughput by avoiding unnecessary extended drying times.
Solution Approach 2:
The system performs preliminary density monitoring during the drying phase to determine the optimal timing for depressurization initiation. By continuously measuring density and detecting when drying completion is achieved, the system prepares for and initiates depressurization at the precise moment when it is safe to do so, ensuring pattern integrity while maximizing productivity.
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 enables earlier initiation of depressurization, improving throughput and preventing pattern collapse by accurately determining drying completion and detecting abnormalities, thus enhancing processing efficiency and product quality.
Implementation Method 1
a density detector configured to detect a density of the mixed fluid flowing through the discharge line
Implementation Method 2
a processing container to which a supercritical fluid is supplied, the processing container being configured to dry a substrate by replacing a drying liquid collected on the substrate with the supercritical fluid
Implementation Method 3
drying a substrate by replacing a drying liquid collected on the substrate with the supercritical fluid
Data Source
AI summary
A substrate processing apparatus includes: a processing container to which a supercritical fluid is supplied, the processing container being configured to dry a substrate by replacing a drying liquid collected on the substrate with the supercritical fluid; a discharge line configured to discharge a mixed fluid containing the supercritical fluid and the drying liquid from an interior of the processing container; and a density detector configured to detect a density of the mixed fluid flowing through the discharge line.