Substrate Drying with Edge Liquid Control and Supercritical Fluid
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Solution Overview
Problem
The existing methods for drying substrates using supercritical fluids face inefficiencies, particularly in preventing natural drying of the edge regions and prolonged drying times, leading to uneven liquid distribution and increased processing times as substrates sag, causing liquid to flow from the edges to the center, and requiring extensive heating which evaporates the liquid from the edges before the center is fully dried.
Innovation Solution
A substrate processing apparatus and method that involves a liquid processing chamber where the substrate is rotated and supplied with a processing liquid, with a higher flow rate and speed on the edge region than the center, ensuring the edge region has a higher liquid height than the center when transferred to a drying chamber, where the substrate is dried using a supercritical fluid, preventing natural drying and optimizing liquid distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the substrate is placed on the support unit to remove processing liquid using supercritical fluid, then the processing liquid can be removed from the substrate, but the substrate sags in the middle causing liquid to flow from edge to center and edge region dries naturally before supercritical fluid supply
Solution Approach 1:
The patent introduces a counterweight unit that applies an upward force to the substrate during the drying process. This counterweight compensates for the sagging of the substrate caused by gravity when placed on the support unit, thereby preventing the liquid flow from edge to center and ensuring uniform liquid distribution across the substrate surface throughout the drying process.
2Reliability
If the drying chamber is heated to maintain supercritical state of fluid, then the supercritical fluid can remove processing liquid, but the edge region of substrate is heated more and evaporates liquid before center is fully dried
Solution Approach 1:
The patent implements local quality control by applying different heating strategies to different regions of the substrate. The heating unit is configured to provide localized heating that compensates for the higher heat loss at the edge regions, ensuring that the entire substrate reaches the required temperature for supercritical fluid drying uniformly, thereby preventing premature evaporation at the edges.
3Reliability
If a large amount of processing liquid is supplied onto the substrate, then the substrate can be thoroughly processed, but it takes a significant amount of time to dry the processing liquid
Solution Approach 1:
The patent utilizes phase transitions of the processing liquid to accelerate the drying process. The system controls the temperature and pressure conditions to facilitate phase change from liquid to vapor more rapidly. Additionally, the counterweight unit maintains uniform liquid distribution which enhances the efficiency of the phase transition process, allowing thorough processing with reduced drying time.
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 enhances drying efficiency by maintaining a controlled liquid level, preventing natural drying of the edge regions and reducing overall drying time, ensuring uniform drying of the substrate using a supercritical fluid.
Implementation Method 1
a drying chamber for removing the processing liquid from the substrate by using a supercritical fluid after the liquid processing
Implementation Method 2
a larger amount of processing liquid is evaporated by the heating from the edge region of the substrate W brought into contact with the support unit 1200
Data Source
AI summary
Disclosed is a method for processing a substrate, comprising a liquid processing step of performing liquid processing on the substrate by supplying a processing liquid onto the substrate in a liquid processing chamber, a transfer step of transferring the substrate from the liquid processing chamber to a drying chamber, and a drying step of drying the substrate in the drying chamber. In the drying step, the substrate is dried while an edge region of the substrate other than a central region of the substrate is supported by a support unit, and in the liquid processing step, the liquid processing is performed on the substrate such that a height of the processing liquid remaining on the edge region of the substrate is greater than a height of the processing liquid remaining on the central region of the substrate when the liquid processing is completed in the liquid processing chamber.