Air Distributor Air Curtain for Endpoint Detection
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Solution Overview
Problem
Endpoint detection errors in semiconductor fabrication processes, such as etching and deposition, often result in over or under etching, leading to wafer scrap and potential damage to the chamber due to inaccurate monitoring of byproduct emissions, which current methods fail to address effectively.
Innovation Solution
An air distributor is installed proximally to the sidewall of a semiconductor manufacturing chamber to create an air curtain that prevents byproducts from forming on the transparent cover, allowing for accurate monitoring of plasma emissions using optical emission spectroscopy (OES) without obstruction, thereby enhancing endpoint detection precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical emission spectroscopy is used to monitor plasma emissions for endpoint detection, then the endpoint detection capability is improved, but byproduct deposition on the transparent cover obstructs the light path and reduces measurement precision
Solution Approach 1:
A gas distributor is introduced as an intermediary component between the plasma chamber and the transparent cover. This gas distributor delivers a protective gas flow that acts as a mediator to prevent byproducts from reaching and depositing on the transparent cover, thereby maintaining optical clarity and ensuring accurate endpoint detection throughout the process
Solution Approach 2:
The patent employs pneumatic means by using a gas distributor to deliver a controlled gas flow. This gas flow creates a protective barrier through aerodynamic principles, preventing reactive byproducts from contacting the transparent cover while allowing optical signals to pass through unchanged for accurate monitoring
2Manufacturing precision
If the plasma etching process continues until no more byproduct is detected, then the etching completeness is improved, but endpoint detection errors cause over or under etching leading to wafer scrap
Solution Approach 1:
The system implements continuous feedback monitoring through optical emission spectroscopy that tracks byproduct emissions in real-time. The gas distributor ensures this feedback remains accurate by preventing byproduct deposition on the optical path, allowing the control system to reliably detect the true endpoint and adjust the etching process accordingly, avoiding both over-etching and under-etching
Solution Approach 2:
The gas distributor is positioned and configured to establish a protective gas flow barrier before byproduct deposition can occur on the transparent cover. This preliminary protective action ensures that the optical monitoring system maintains accurate detection capabilities throughout the entire etching process, enabling reliable endpoint detection
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 air curtain solution ensures that light emissions from the chamber can be detected with high accuracy, preventing byproduct deposition on the transparent cover and improving the precision of endpoint detection, reducing wafer scrap and chamber damage by maintaining process control and optimizing etching and deposition processes.
Implementation Method 1
an air distributor between the view port window and the pedestal, wherein the air distributor has a hollow region configured to have an air curtain formed therein
Implementation Method 2
endpoint detection may also rely on light emitted by the plasma during the etching reaction. This light includes emissions at wavelengths representative of specific substances present in the plasma
Data Source
AI summary
A semiconductor manufacturing apparatus includes an air distributor inside a chamber. The air distributor includes a first annular plate and a second annular plate disposed in an interior volume of the chamber, and an inner surface of the first annular plate and an inner surface of the second annular plate are connected to each other. A hollow region is defined by the first annular plate and the second annular plate. A gas through hole is extended from an outer surface of the first annular plate to the inner surface of the first annular plate. A plurality of ditches are between the inner surface of the first annular plate and the inner surface of the second annular plate, wherein the ditches are connected with the gas through hole and extended from the gas through hole to the hollow region to blow gas toward the hollow region.