Spin Coating Cup Structure for Exhaust Path Clog Prevention
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Solution Overview
Problem
In the spin coating process for semiconductor wafers, high-viscosity coating liquids can lead to filamentous foreign substances that clog the exhaust path, preventing the desired exhaust pressure and causing mist-like coating liquid to contaminate the surroundings.
Innovation Solution
A liquid processing apparatus with a mesh ring coating liquid collector and solvent supplier system, where the mesh ring has openings for exhaust flow and a liquid receiver to collect and dilute resist liquid, preventing clogging by using a solvent to dissolve solidified substances and maintain exhaust pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-viscosity coating liquid is used for spin coating, then coating quality is improved, but filamentous foreign substances are generated that clog the exhaust path
Solution Approach 1:
The patent extracts and removes the harmful filamentous foreign substances and solidified coating liquid from the exhaust path by introducing a solvent (such as isopropyl alcohol) that dissolves these substances. The solvent is supplied to the exhaust path area where it dissolves the clogging materials, allowing them to be carried away by the exhaust flow, thus clearing the exhaust path while maintaining the ability to use high-viscosity coating liquids for quality coating.
2Stress or pressure
If exhaust path is clogged with solidified substances, then exhaust pressure decreases, but contamination of surroundings by mist-like coating liquid increases
Solution Approach 1:
The patent applies preliminary action by proactively supplying solvent to the exhaust path area before complete clogging occurs. The solvent continuously dissolves solidified coating liquid and filamentous foreign substances, preventing them from accumulating and blocking the exhaust path. This preliminary dissolution action maintains exhaust pressure at desired levels and prevents the formation of mist-like coating liquid that would contaminate the surroundings.
3Productivity
If mesh ring coating liquid collector is used with openings, then exhaust flow is facilitated, but liquid collection efficiency may be reduced
Solution Approach 1:
The patent applies local quality by creating different functional zones within the coating liquid collector. The mesh ring structure provides openings in certain areas to facilitate exhaust flow, while other areas maintain solid structures for effective liquid collection. This spatial differentiation of properties allows the same component to simultaneously achieve both exhaust flow efficiency and liquid collection effectiveness without compromising either function.
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
Prevents clogging of the exhaust path, ensuring effective exhaust and reducing contamination by facilitating the discharge of resist liquid and solidified substances, thus maintaining the desired exhaust pressure and process efficiency.
Implementation Method 1
a solvent supplier configured to supply a solvent for the coating liquid to a coating liquid collector
Implementation Method 2
the coating liquid collector provided with a plurality of openings through which an exhaust flow passes
Data Source
AI summary
A liquid processing apparatus that applies a coating liquid onto a substrate, includes: a substrate holder that holds and rotates the substrate; a coating liquid supplier that supplies the coating liquid to the substrate; a cup provided to surround the substrate; and a solvent supplier that supplies a solvent for the coating liquid to a coating liquid collector. The cup includes: an outer cup arranged outside the substrate holder; an inner cup arranged on an inner peripheral side of the outer cup below the substrate holder and having a downwardly-extending wall; an exhaust path provided between the outer and inner cups; and the coating liquid collector provided with a plurality of openings through which an exhaust flow passes, the coating liquid collector extending downward below the downwardly-extending wall of the inner cup with a gap between the coating liquid collector and a lower end of the downwardly-extending wall.