Etching Process State Judgment via Optical Emission Spectrum Analysis
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Solution Overview
Problem
Existing methods for judging the state (anomaly or normalcy) of an etching process based on optical emission spectrum distribution are limited, as they rely on predefined peak wavelengths, making it impossible to detect peaks at different wavelengths, thereby failing to accurately assess the etching process state.
Innovation Solution
A method that involves acquiring optical emission spectrum distributions during etching, detecting peaks, identifying common peaks, and comparing their characteristics to determine the state of each wafer, using spectral ratios, standard deviations, and dispersion indices to detect anomalies without assuming the substances involved.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If predefined peak wavelengths are used for substance identification, then the identification process is simplified, but peaks at different wavelengths cannot be detected, reducing measurement precision
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing spectral ratios for multiple reference substances at various wavelength positions before actual measurement. When analyzing a sample, the system compares the measured spectral ratio against these pre-prepared reference values to identify substances, eliminating the need for real-time complex calculations while maintaining the ability to detect peaks at any wavelength.
Solution Approach 2:
The patent transforms the identification approach by changing from fixed wavelength peak detection to spectral ratio analysis. Instead of looking for peaks at predetermined wavelengths, the system calculates ratios of intensities at different wavelengths and compares these ratios to reference data, enabling flexible detection of substances regardless of their specific peak positions.
2Adaptability or versatility
If spectral analysis is performed without substance assumptions, then adaptability to unknown substances is improved, but the complexity of data processing increases
Solution Approach 1:
The patent reduces processing complexity by changing the analysis parameter from raw spectral intensity to spectral ratio. By dividing the spectrum into multiple wavelength regions and calculating intensity ratios, the system transforms complex spectral data into simplified ratio values that are easier to compare and analyze, while maintaining adaptability to identify unknown substances.
Solution Approach 2:
The patent creates simplified copies of spectral information in the form of spectral ratios. Instead of processing the entire complex spectrum, the system extracts and stores representative ratio values for reference substances, which serve as simplified models for quick comparison and identification during actual measurements.
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 accurate detection of etching process states from optical emission spectrum distributions, allowing for real-time monitoring and prediction of etching performance without relying on predefined substance data, thus improving the reliability of etching process control.
Implementation Method 1
Ionization by plasma is accompanied by an optical emission phenomenon. Accordingly, etching equipment using plasma in its process is provided with an Optical Emission Spectrometry (OES) to monitor a state of plasma generation.
Data Source
AI summary
An etching process state judgment method comprising: a spectral data obtaining step, in which an optical emission spectrum distribution is obtained by monitoring optical emission during an etching process of a plurality of wafers; a peak detection step, in which peaks are detected from the optical emission spectrum distribution at a specific time point during the etching process, to obtain peak characteristics; a common peak identifying step, in which peaks common to the wafers are identified among the peaks detected in the peak detection step; and a state detection step, in which the characteristics are compared regarding the common peaks, to detect a state of each wafer in the etching process.A state (anomaly or normalcy) of an etching process is detected from optical emission spectrum distribution at the time of etching process, by a simple method without assuming substances.