Plasma Etching Spectroscopy Control Under Recipe Changes
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Solution Overview
Problem
Existing plasma processing methods struggle to maintain consistent etching results due to fluctuations in plasma state and recipe changes, as they do not account for the changing correlation between spectroscopic measurement data and etching results.
Innovation Solution
A plasma processing apparatus and method that utilizes feedback or feedforward control to stabilize etching results by determining a combination of emission wavelength, time interval, and recipe parameters through regression analysis, ensuring minimal changes in correlation even with recipe adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spectroscopic measurement data is used for APC control, then etching result stability is improved, but the correlation between measurement data and etching result changes when recipe parameters are adjusted
Solution Approach 1:
The patent applies dynamics by making the APC control parameters (wavelength and time interval) adjustable and adaptable. Instead of using fixed parameters, the system dynamically selects optimal parameters based on the specific recipe being used. This allows the measurement system to adapt to different plasma conditions caused by recipe changes, maintaining stable correlation between measurement data and etching results across various processing conditions.
Solution Approach 2:
The patent directly applies parameter changes by optimizing the wavelength and time interval parameters of the spectroscopic measurement system. By carefully selecting specific wavelength bands and time intervals that show minimal sensitivity to recipe parameter variations, the system maintains stable correlation between measurement data and etching results. This parameter optimization ensures that the same measurement parameters can be used across different recipes, resolving the contradiction between reliability and adaptability.
2Adaptability or versatility
If recipe parameters are changed to adjust etching results, then etching flexibility is improved, but the correlation between spectroscopic measurement data and etching result becomes unstable
Solution Approach 1:
The patent applies preliminary action by pre-determining the optimal wavelength and time interval parameters for each recipe through offline analysis and experimentation. Before actual etching processes begin, the system identifies which measurement parameters will provide the most stable correlation with etching results for each specific recipe. This preliminary parameter selection ensures that when recipe parameters are changed during processing, the measurement system is already configured to maintain stable correlation, thus preserving reliability while allowing etching flexibility.
3Ease of operation
If APC control is implemented using fixed measurement parameters, then control simplicity is improved, but control accuracy decreases when plasma conditions change
Solution Approach 1:
The patent applies universality by establishing a set of optimized measurement parameters (wavelength and time interval combinations) that can be universally applied across multiple different recipes and plasma conditions. Instead of requiring unique parameters for each specific condition, the system identifies measurement parameters that maintain stable correlation with etching results across a broad range of processing conditions. This universal parameter set simplifies APC control while maintaining high precision, as the same measurement approach works effectively for various etching scenarios.
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 stabilizes etching results by identifying optimal wavelength and time intervals for spectroscopic measurement data, allowing for precise control and consistent plasma processing outcomes.
Implementation Method 1
measuring the light emitted from the plasma during etching
Data Source
AI summary
A plasma processing apparatus, plasma processing method, and plasma processing analysis method in which a suitable combination of wavelength, time interval, and etching condition parameter for control to change etching conditions is determined among wavelengths, time intervals, and changeable parameters for spectroscopic measurement data in order to ensure stable etching conditions. Specifically, a regression equation which represents the correlation between emission intensity and etching result at a wavelength and a time interval is obtained for each of two or more combinations of wavelength, time interval, and etching condition parameter. Furthermore, for each of the combinations, the amount of change is calculated from the regression equation when the value set for the etching condition parameter is changed. Among the combinations, the combination for which the amount of change is the smallest is determined as the combination of wavelength, time interval, and changed etching condition parameter to be used for control.