Optical Proximity Effect Correction Verification Using Center of Gravity Analysis
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Solution Overview
Problem
In the context of small-sized and highly-integrated semiconductor devices, the proximity between patterns leads to interference and diffraction of light, resulting in distorted patterns on substrates, which existing resolution enhancement technologies like optical proximity effect correction struggle to accurately verify and correct, particularly in detecting defect patterns with asymmetry.
Innovation Solution
The method involves generating a design pattern layout, applying optical proximity effect correction to create a correction pattern layout, and then detecting defect patterns by calculating the center of gravity of image patterns, comparing them to a reference, and correcting the layout using this data, with the center of gravity calculated as the sum of position data of fine patterns within the image pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If optical proximity effect correction is applied to correct distorted patterns, then pattern shape accuracy is improved, but difficulty in detecting defect patterns with asymmetry increases
Solution Approach 1:
The patent applies asymmetry principle by intentionally introducing asymmetric dummy patterns around symmetric target patterns. These dummy patterns create asymmetric optical proximity effects that can be used as reference markers. When defect patterns occur, they disrupt this intentional asymmetry, making defects detectable through symmetry analysis. This resolves the contradiction by using controlled asymmetry to enable defect detection while maintaining the correction of symmetric pattern shapes.
Solution Approach 2:
The patent introduces dummy patterns as intermediary elements that mediate between the symmetric target patterns and the defect detection process. These dummy patterns serve as reference markers that facilitate the detection of asymmetric defects without interfering with the correction of the target patterns themselves. The dummy patterns act as a bridge that enables defect detection while preserving pattern shape accuracy.
2Productivity
If pattern size is reduced to achieve high integration, then device integration density is improved, but light interference and diffraction effects worsen
Solution Approach 1:
The patent applies preliminary anti-action by pre-calculating and compensating for light interference and diffraction effects during the optical proximity effect correction process. Before actual lithography, the system predicts how light will interfere and diffract at the reduced scale, and applies corrective adjustments to the pattern design in advance. This prevents the harmful optical effects from manifesting in the final pattern, enabling high integration density without suffering from light interference and diffraction.
3Productivity
If distance between patterns is reduced to increase integration, then device miniaturization is improved, but optical distortion increases
Solution Approach 1:
The patent applies local quality principle by applying different correction strategies to different regions of the pattern layout. Areas with high pattern density receive more aggressive optical proximity effect correction, while isolated patterns receive minimal correction. The dummy patterns are strategically placed in specific local regions where they can provide reference information for defect detection without affecting the overall integration density. This localized approach enables high device integration while maintaining pattern shape precision through region-specific corrections.
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 effectively verifies and corrects optical proximity effect correction by accurately detecting defect patterns, improving the symmetry and shape of semiconductor device patterns, thereby enhancing the precision of lithography processes.
Implementation Method 1
interference and diffraction of light may occur to form a distorted pattern
Implementation Method 2
interference and diffraction of light may occur to form a distorted pattern
Data Source
AI summary
A method of verifying optical proximity effect correction includes generating a design pattern layout including a target pattern, generating a correction pattern layout from the design pattern layout by performing optical proximity effect correction, generating a contour image including an image pattern using the correction pattern layout, detecting a defect pattern from the image pattern of the contour image, and correcting the correction pattern layout using data of the defect pattern. Detecting the defect pattern includes acquiring position data of a center of gravity of the target pattern, acquiring position data of a center of gravity of the image pattern, and determining whether the image pattern is a defect pattern by comparing a defect pattern detection reference with a distance between the center of gravity of the target pattern and the center of gravity of the image pattern.