OES Wavelength Identification for Etching Process Control
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Solution Overview
Problem
Existing methods for controlling the etching process in semiconductor wafer manufacturing are limited in selecting effective wavelengths for monitoring and controlling the process, especially at intermediate time points, and fail to distinguish whether light emission intensity fluctuations are caused by substances within the plasma.
Innovation Solution
An analysis method and system that processes Optical Emission Spectroscopy (OES) data to identify the wavelength of light emitted from substances in the plasma by measuring time-based fluctuations and comparing them to pre-specified substances, allowing for accurate monitoring and control of the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the wavelength is selected based on light emission intensity at two specified time points, then the endpoint detection is achieved, but the method is incapable of selecting an effective wavelength for controlling the etching process at intermediate time points
Solution Approach 1:
The method performs preliminary analysis of light emission intensity fluctuations across all wavelengths during the etching process to identify candidate wavelengths before endpoint detection. This preliminary action enables the system to have pre-identified effective wavelengths ready for use at any time point during etching, not just at the endpoint.
Solution Approach 2:
The invention dynamically selects wavelengths based on the actual etching process stage. By analyzing fluctuation patterns at different time points and adapting wavelength selection accordingly, the system transitions from static two-point measurement to dynamic multi-point wavelength identification, making it versatile for intermediate time points.
2Extent of automation
If the light emission intensity is monitored to control the etching process, then process control is achieved, but it is difficult to determine whether the intensity fluctuations are caused by substances contained in the plasma
Solution Approach 1:
The system continuously monitors light emission intensity fluctuations and uses this feedback to identify wavelengths characteristic of specific plasma substances. By establishing the relationship between fluctuation patterns and substance presence, the system can automatically determine the source of intensity changes and adjust process control accordingly.
Solution Approach 2:
The invention introduces wavelength analysis as an intermediary between light emission monitoring and process control. Instead of directly controlling based on raw intensity data, the system uses wavelength-specific fluctuation analysis to mediate, identifying which substances are present in the plasma and using that information for accurate process control.
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
Enables precise identification of the wavelength emitted from substances in the plasma, improving the accuracy of the etching process by correlating light emission intensity fluctuations, thereby enhancing process control and efficiency.
Implementation Method 1
a spectroscope (OES: Optical Emission Spectroscope) capable of monitoring the plasma emission status. Data measured by a spectroscope is hereafter called OES data. The OES data contains two dimensional spatial and temporal elements and expresses the emission intensity values respectively measured at each time and wavelength.
Implementation Method 2
In order to achieve a microscopic shape such as for a semiconductor device formed over a wafer, plasma is utilized to ionize a substance, and by using the effect from that substance, (reaction with wafer surface) etching is performed to remove a substance over the wafer.
Implementation Method 3
plasma is utilized to ionize a substance
Data Source
AI summary
Among the multiple OES data wavelengths, an analysis device identifies the wavelength of light emissions from a substance contained in the plasma from among multiple light emission wavelengths within the chamber by way of the steps of: measuring the light emission within the chamber during etching processing of the semiconductor wafer; finding the time-based fluctuation due to changes over time on each wavelength in the measured intensity of the light emissions in the chamber; comparing the time-based fluctuations in the wavelength of the light emitted from the pre-specified substance; and by using the comparison results, identifying the wavelength of the light emitted from the substance caused by light emission within the chamber.