Substrate Processing Facing Member Gap Control
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Solution Overview
Problem
Existing substrate processing apparatuses face contamination issues on the lower surface of substrates due to mist of processing liquid entering the gap between the protective disk and the substrate's circumferential edge during processing.
Innovation Solution
A substrate processing apparatus with a spin base, holding portions, a facing member that can be raised and lowered, and a gas supply system to direct a gas flow between the facing member and the substrate, featuring a flat surface on the facing member to minimize the gap and prevent contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a protective disk is provided between the spin base and substrate to prevent mist contamination, then contamination protection is improved, but a gap remains at the circumferential edge allowing mist to pass through
Solution Approach 1:
The facing member is made movable between a separated position and a near position, allowing dynamic adjustment of the gap size. During processing, the facing member is positioned close to the substrate to minimize the gap and prevent mist infiltration, while still allowing substrate insertion and removal.
Solution Approach 2:
The distance parameter between the facing member and substrate is changed from a fixed large gap to a dynamically adjustable small gap. By controlling the position of the facing member (separated vs. near positions), the gap size is optimized to prevent mist contamination while maintaining operational feasibility.
2Object-affected harmful factors
If the facing member is positioned close to the substrate to minimize the gap, then mist infiltration is reduced, but the complexity of the raising and lowering mechanism increases
Solution Approach 1:
The function of preventing mist infiltration is extracted from a fixed structural arrangement and implemented through a movable facing member that can be positioned as needed. This separates the contamination prevention function from the substrate holding function, allowing independent optimization of each.
Solution Approach 2:
The facing member acts as an intermediary element between the spin base and substrate. It provides a controllable barrier that can be dynamically positioned to prevent mist infiltration without requiring direct modification of the substrate or spin base structures.
3Object-affected harmful factors
If gas flow velocity is increased to prevent processing liquid from entering the gap, then contamination protection is improved, but energy consumption increases
Solution Approach 1:
Gas is supplied to the space between the facing member and substrate before processing liquid can infiltrate the gap. This preliminary gas flow establishment creates a protective barrier that prevents contamination without requiring excessive gas flow rates during the entire processing cycle.
Solution Approach 2:
The gas flow is maintained continuously in the gap space during substrate processing, providing ongoing protection against mist infiltration. The continuous low-velocity gas flow is more energy-efficient than intermittent high-velocity flows while maintaining effective contamination prevention.
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 reduces contamination on the lower surface of substrates by increasing the linear velocity of the gas flow and straightening it to prevent processing liquid from entering the gap, thereby protecting the substrate from contamination.
Implementation Method 1
a gas supply portion that supplies a gas to a space between the facing member and the substrate which is held by the plurality of holding portions
Implementation Method 2
a spin base that rotates around a rotation axis extending in a vertical direction
Implementation Method 3
a plurality of holding portions that are provided in the spin base with intervals therebetween in a rotation direction of the spin base and hold a circumferential edge portion of the substrate above the spin base
Data Source
AI summary
A protective disk is disposed between a spin base and a substrate W and is capable of being raised and lowered between a separated position which is separated downward from the substrate W and a near position which is nearer to the substrate than the separated position. An upper surface of the protective disk has an inner surface which is provided on an inner side of a plurality of holding pins in a radial direction and a flat surface which is provided on an outer side of the inner surface in the radial direction and is provided above the inner surface. The flat surface faces a lower surface of a part on an inner side of an outer circumferential end in the radial direction, in a circumferential edge portion of the substrate.