Semiconductor Overlay Data Filtering by Field
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Solution Overview
Problem
In semiconductor manufacturing, overlay errors between patterned layers occur due to alignment accuracy issues and other manufacturing process influences, necessitating effective monitoring and modification of exposure parameters to ensure accurate integrated circuit formation.
Innovation Solution
A method of filtering overlay data by field is implemented, where a minimum number of measure points per field are determined, and field data filtering rules are set to remove measure points with extreme overlay errors, ensuring that modified exposure parameters can be generated effectively by retaining sufficient data points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If overlay raw data is used directly to generate modified exposure parameters, then the process is simple, but extreme overlay errors will affect the accuracy of the modified exposure parameters
Solution Approach 1:
The patent applies preliminary action by performing data filtration before generating modified exposure parameters. The system pre-processes overlay raw data by identifying and removing outliers that exceed predetermined thresholds, ensuring that only valid data points are used in subsequent parameter calculations. This preliminary filtering step prevents extreme values from corrupting the final exposure parameters while maintaining a relatively simple overall process.
Solution Approach 2:
The patent applies the extraction principle by separating and removing outlier data points from the overlay raw data. The system extracts invalid measurements that fall outside acceptable ranges and excludes them from the dataset used to calculate modified exposure parameters. This selective extraction ensures that only representative data points influence the final parameters, improving accuracy without requiring complete reprocessing of all data.
2Manufacturing precision
If all measure points are used to generate modified exposure parameters, then data quantity is maximized, but extreme overlay errors will skew the results
Solution Approach 1:
The patent converts the harmful effect of outliers into a beneficial filtering mechanism. By establishing predetermined thresholds based on statistical analysis or process specifications, the system identifies extreme values as indicators of measurement errors or anomalies rather than treating them as valid data. This approach transforms potentially corrupting extreme values into useful signals for data quality control, improving both accuracy and robustness.
Solution Approach 2:
The patent implements feedback by using the distribution and characteristics of overlay data to dynamically determine which points should be filtered. The system continuously monitors measure points against established criteria, and when outliers are detected, they are removed from subsequent calculations. This feedback loop ensures that the data used for generating modified exposure parameters consistently meets quality standards, enhancing both precision and reliability.
3Manufacturing precision
If measure points with extreme overlay errors are included, then the dataset is complete, but the modified exposure parameters will be less effective in reducing overlay error
Solution Approach 1:
The patent applies parameter changes by modifying the threshold criteria for data inclusion based on process requirements and data characteristics. Instead of using fixed filtering rules, the system can adjust predetermined thresholds to optimize the balance between data retention and outlier removal. This flexible parameter adjustment ensures that valid measurement data is preserved while effectively excluding only those extreme values that would genuinely harm parameter accuracy.
Data Source
AI summary
A method of filtering overlay data by field is provided in the present invention. The method includes the following steps. A minimum number of measure points per field on a semiconductor substrate is decided. Field data filtering rules are set. Overlay raw data is inputted. A raw data filtration is performed to the overlay raw data by field according to the field data filtering rules. Modified exposure parameters are generated for each field according to overlay data of remaining measure points per field after the raw data filtration when the number of the remaining measure points per field is larger than or equal to the minimum number of the measure points per field. Accordingly, the modified exposure parameters will be more effective in reducing the overlay error because more outliers may be filtered out before generating the modified exposure parameters.