Supercritical Drying Apparatus for Preventing Pattern Collapse
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Solution Overview
Problem
The supercritical drying process for substrates faces challenges due to the low fluidity of the drying gas in a supercritical state, which hampers the delivery of the drying gas to the substrate and the removal of organic solvents, potentially leading to incomplete drying and pattern collapse.
Innovation Solution
The proposed solution involves an apparatus and method that control the pressure in the process chamber by repeatedly changing it between two set pressures, using a controller to manage the fluid supply and exhaust units, ensuring a balanced flow of the drying gas and maintaining the pressure at a set level during the drying process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the drying gas is maintained in a supercritical state in the process chamber, then the solubility and permeability of the drying gas are improved, but the fluidity of the drying gas deteriorates
Solution Approach 1:
The patent applies periodic pressure changes to the drying gas in the supercritical state. By cyclically varying the pressure, the patent generates fluid flow that enhances the delivery of drying gas to the substrate and improves the removal of organic solvents, thereby overcoming the low fluidity inherent in supercritical states while maintaining high solubility and permeability
2Speed
If the pressure in the process chamber is repeatedly changed between two set pressures, then the flow of drying gas is improved, but the time required for the drying process increases
Solution Approach 1:
The patent optimizes the pressure change parameters including the magnitude of pressure variation, the rate of pressure change, and the frequency of pressure cycles. By carefully selecting these parameters, the patent achieves effective drying gas flow and organic solvent removal while minimizing the total process time, thus resolving the contradiction between flow improvement and time efficiency
3Loss of time
If valves are rapidly turned on/off to reduce pressure change time, then the drying process time is reduced, but the pressure control accuracy deteriorates and flow may be hampered
Solution Approach 1:
The patent employs dynamic pressure control where the pressure change rate and valve operation timing are continuously adjusted based on real-time process conditions. This dynamic approach allows the system to achieve both rapid pressure changes for time efficiency and sufficient pressure control accuracy for maintaining proper drying gas flow, resolving the contradiction between speed and precision
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 the efficiency of the drying process by ensuring effective delivery and release of the drying gas, reducing the time required for drying, minimizing impurities like particles, and preventing pattern collapse.
Implementation Method 1
The drying gas in the supercritical state has high solubility and permeability. That is, when the drying gas in the supercritical state is supplied to the substrate, the drying gas easily permeates into patterns on the substrate, and the organic solvent remaining on the substrate is easily dissolved in the drying gas.
Implementation Method 2
The drying gas in the supercritical state has high solubility and permeability. That is, when the drying gas in the supercritical state is supplied to the substrate, the drying gas easily permeates into patterns on the substrate
Implementation Method 3
a drying gas is supplied into a sealed process chamber, and the drying gas is heated and pressurized. The temperature and pressure of the drying gas are raised to critical points or more, and the drying gas experiences a phase change into a supercritical state.
Data Source
AI summary
An apparatus for treating a substrate includes a body having an inner space in which the substrate is dried by a drying fluid in a supercritical state, a fluid supply unit that supplies the drying fluid into the inner space, a fluid exhaust unit that releases the drying fluid from the inner space, and a controller. The controller controls the fluid supply unit and the fluid exhaust unit to perform a pressure-raising step of raising pressure in the inner space to a set pressure and a flow step of generating a flow of the drying gas in the inner space by releasing, by the fluid exhaust unit, the drying fluid from the inner space while the fluid supply unit supplies the drying fluid into the inner space.