Supercritical Substrate Flow Layout for Laminar Contamination Control
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Solution Overview
Problem
In substrate processing using supercritical fluids, turbulent flows often occur due to imbalances in fluid supply and discharge, temperature differences, and convection, leading to impurity adherence on the substrate, which contaminates it.
Innovation Solution
A substrate processing apparatus with a configuration that introduces and discharges supercritical processing fluid at different temperatures over and under the substrate, creating a temperature difference to suppress fluid currents and maintain laminar flow, thereby preventing turbulent flows and impurity adherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a processing fluid is supplied from a lateral side opposite the opening to process the substrate, then the substrate can be processed efficiently in a compact container, but impurity from the sealing member may adhere to the substrate
Solution Approach 1:
The processing container is divided into an upper space and a lower space by a partition wall. The substrate is placed on the partition wall, separating the flow paths of the processing fluid. This segmentation prevents impurity-laden fluid from the lower space from contacting the substrate surface, while still allowing efficient processing from both upper and lower directions.
Solution Approach 2:
The partition wall acts as an intermediary structure that physically separates the processing fluid flow paths. It allows the substrate to be processed by supercritical fluid from both upper and lower spaces while preventing direct contact between impurity-containing fluid and the substrate, thus mediating between processing efficiency and contamination prevention.
2Quantity of substance
If the processing container is made compact with minimal internal space, then the amount of processing fluid used is reduced, but turbulent flow may occur causing impurity to adhere to the substrate
Solution Approach 1:
By segmenting the container into upper and lower spaces with a partition wall, the patent maintains a compact overall size while creating separate laminar flow paths. This prevents turbulent flow between spaces and ensures that even in a compact container, impurity-laden fluid does not contact the substrate.
Solution Approach 2:
The patent applies different flow conditions to different local regions: the upper space provides laminar flow directly onto the substrate surface for cleaning, while the lower space can have different flow characteristics. This local differentiation allows compact design while maintaining laminar flow quality where needed most.
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 apparatus effectively forms laminar flows over and under the substrate, reducing turbulent flow occurrences and preventing impurity adherence, thus ensuring cleaner substrate processing.
Implementation Method 1
a first temperature difference between the upper space and the lower space in the processing space is generated by the fluid supplier
Implementation Method 2
laminar flows are formed both in the upper space and in the lower space
Implementation Method 3
processing fluid in a supercritical state is supplied into the processing space
Implementation Method 4
convection developed by a difference in temperature between a member in the processing container and the processing fluid
Implementation Method 5
a turbulent flow might be caused by reason such as a current of the processing fluid generated between an upper layer and a lower layer
Data Source
AI summary
A substrate processing apparatus according to the invention executes a substrate processing using a supercritical processing fluid. In a processing container, a first introduction port is formed in such a manner as to face space over a substrate in the processing space and a second introduction port is formed in such a manner as to face space under a support tray in the processing space. A first discharge port is formed in such a manner as to face space over the support tray and a second discharge port is formed in such a manner as to face the space under the support tray. The supercritical processing fluid having a higher temperature is supplied into the processing space through the first introduction port, and the supercritical processing fluid having a lower temperature is supplied into the processing space through the second introduction port.