Substrate Processing Splash Prevention Gas Flow Control
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Solution Overview
Problem
In substrate processing apparatuses, the uniformity and constancy of the downflow gas in the processing chamber are not consistently maintained, leading to insufficient gas flow for preventing splashes and mist from adhering to the lower surface of the substrate, and turbulence at the outer peripheral end can cause processing liquid to re-adhere to the substrate.
Innovation Solution
A substrate processing apparatus is designed with a splash preventer that includes a first inner wall, a first outer wall, and a coupler forming an annular space, which is covered by an annular outer upper member, and a storage with a second inner wall and outer wall forming a second annular space, allowing the splash preventer to move up and down to communicate these spaces. A gas discharger is used to suck gas through an annular opening, preventing turbulence and re-adhesion of processing liquid to the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a splash prevention member is provided to receive processing liquid, then processing liquid splashes are contained, but splashes and mist may still adhere to the back surface of the substrate due to insufficient gas flow
Solution Approach 1:
The gas discharge path is segmented into multiple regions: a first discharge path for the upper portion of the splash prevention member and a second discharge path for the lower portion. This segmentation allows independent control of gas flow in different regions, ensuring sufficient gas flow reaches the substrate back surface without causing turbulence at the outer peripheral end.
Solution Approach 2:
Different gas flow characteristics are provided in different locations: the first discharge path provides gas flow for the upper region while the second discharge path provides gas flow for the lower region. This local differentiation ensures that each region receives appropriate gas flow to prevent liquid adhesion without generating harmful turbulence.
2Object-affected harmful factors
If gas flow amount from above the substrate to the splash prevention cup is increased, then splashes are prevented from flowing to the lower surface, but turbulence is generated around the outer peripheral end causing processing liquid to re-adhere
Solution Approach 1:
The gas discharge system is divided into two separate discharge paths: a first discharge path that discharges gas above the substrate to prevent liquid flow to the lower surface, and a second discharge path that discharges gas at the outer peripheral end to suppress turbulence. This segmentation allows each path to be optimized for its specific function without interfering with the other.
Solution Approach 2:
The second discharge path acts as an intermediary mechanism that introduces gas at the outer peripheral end to counteract the turbulence generated by the first discharge path. This intermediary gas flow suppresses the harmful turbulence and prevents processing liquid from re-adhering to the substrate.
3Object-affected harmful factors
If downflow gas uniformity is not maintained, then sufficient gas flow cannot be generated to prevent splashes and mist, leading to processing liquid adhesion on the lower surface
Solution Approach 1:
The gas discharge system is segmented into multiple discharge paths with different discharge positions and flow characteristics. This segmentation ensures that gas flow is distributed uniformly throughout the processing chamber, with specific regions receiving targeted gas flow to maintain stability and prevent liquid adhesion.
Solution Approach 2:
Different discharge paths provide gas flow with different local characteristics: the first discharge path provides downward gas flow for the upper region, while the second discharge path provides gas flow at the outer peripheral end. This local quality differentiation ensures uniform overall gas flow distribution while maintaining stability in each specific region.
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 prevents processing liquid from adhering to the lower surface of the substrate by creating a controlled gas flow that shields the substrate from splashes and mist, ensuring efficient collection and reducing turbulence-induced re-adhesion.
Implementation Method 1
the gas flowing between the splash prevention cup and the outer cup due to a downflow of gas in the processing chamber is led to the space between the back surface of the substrate held by the spin chuck and the inclined current surface of the current member through the divert path
Implementation Method 2
A processing liquid is supplied to a main surface (an upper surface) of the substrate rotated by a spin chuck, for example. A splash prevention member is provided to surround the substrate held by the spin chuck. The processing liquid, splashed from the substrate, of the supplied processing liquid is received by the splash prevention member.
Data Source
AI summary
A cleaning drying processing unit includes a lower spin chuck, a splash prevention cup, and a storage member. The splash prevention cup is provided to surround the lower spin chuck, and has an annular opening that can be opposite to an outer peripheral end of a substrate rotated by the lower spin chuck. A lower portion of the splash prevention cup is stored in the storage member. Cleaning and drying processing using a cleaning liquid are performed on the substrate rotated by the lower spin chuck. At this time, the splash prevention cup is supported such that the annular opening is opposite to the outer peripheral end of the substrate. Gas in a space opposite to the annular opening is sucked from the annular opening through a first annular space of the splash prevention cup and a second annular space in the storage member.