Endpoint Detection Algorithm for Atomic Layer Etching
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Solution Overview
Problem
Current endpoint detection algorithms for plasma etching processes, particularly in atomic layer etching, face challenges in accurately detecting the endpoint due to subtle changes in optical emission spectra, especially in materials with low open ratios, leading to difficulties in determining when the etching process has reached the underlying layer.
Innovation Solution
The implementation of a synchronized, filtered, and averaged optical emission spectroscopy (OES) data processing method, utilizing a Fusion Algorithm or principal component analysis, to distinguish between absorption and desorption steps and identify endpoints by analyzing quiescent portions of the signal curve, thereby enhancing the robustness of endpoint detection in challenging etch conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current endpoint detection algorithms are used for plasma etching processes, then the detection process is simple, but the accuracy of endpoint detection deteriorates due to subtle changes in optical emission spectra
Solution Approach 1:
The patent segments the optical emission spectrum into multiple wavelength channels and processes each channel separately through synchronized filtering and averaging. This segmentation allows the system to capture subtle changes in specific wavelength regions while maintaining overall spectral information, thereby improving endpoint detection accuracy without requiring excessive computational complexity
Solution Approach 2:
The patent implements periodic synchronized filtering and averaging of OES data across multiple etching cycles. By performing repeated measurements and averaging the results, the system enhances the signal-to-noise ratio and detects subtle spectral changes that indicate endpoint conditions, improving measurement precision through periodic data acquisition and processing
2Reliability
If OES data is processed without synchronization and filtering, then the processing time is short, but the reliability of endpoint detection deteriorates due to transient signals
Solution Approach 1:
The patent performs preliminary synchronization of OES data with the etching process timing before endpoint detection analysis. By pre-aligning the spectral data with process events and filtering out transient signals in advance, the system ensures that only relevant endpoint information is analyzed, improving reliability while minimizing the actual detection processing time
Solution Approach 2:
The patent implements continuous synchronized collection and filtering of OES data throughout the etching process. This continuous data acquisition with real-time synchronization ensures that endpoint conditions are captured reliably without interruption, maintaining high detection reliability while optimizing the balance between data collection and processing time
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
This approach improves the accuracy and reliability of endpoint detection in plasma etching processes by filtering out transient signals and averaging the signal curves, allowing for precise determination of endpoint conditions, even in cases where changes are subtle, thus optimizing the etching process.
Implementation Method 1
endpoint detection based on optical emission spectroscopy (OES) data
Data Source
AI summary
Described herein are architectures, platforms and methods for determining endpoints of an optical emission spectroscopy (OES) data acquired from a plasma processing system. The OES data, for example, includes an absorption—step process, a desorption—step process, or a combination thereof. In this example, the OES data undergoes signal synchronization and transient signal filtering prior to endpoint determination, which may be implemented through an application of a moving average filter.