Photolithographic Mask Design Rippling Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current photolithographic techniques suffer from rippling issues in printed features due to the accentuation of high spatial frequencies, leading to inaccuracies in reproducing circuit designs on substrates, particularly in low k1 systems where conventional model-based OPC methods fail to effectively minimize mismatch between target and predicted images.
Innovation Solution
A novel method that determines deviations between design representations at multiple evaluation points, identifies section types, and applies specific modification techniques based on corner types and evaluation methods such as minimum, maximum, middle, mean, and median to optimize the design and suppress rippling, using a flowchart to guide the evaluation and modification process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional model-based OPC methods are used to image small features in low k1 systems, then high spatial frequencies are accentuated to improve resolution, but this causes rippling and waviness in the printed features
Solution Approach 1:
The patent divides the target image into multiple sections and evaluates each section independently at multiple evaluation points. This segmentation allows localized optimization of each section to suppress rippling while maintaining the ability to resolve small features through targeted modifications in each zone.
Solution Approach 2:
The patent applies different evaluation methods (minimum, maximum, middle, mean, median) to different sections based on their local characteristics. Corner sections receive special treatment with tailored modification strategies, while other sections use appropriate evaluation methods suited to their specific geometric properties and rippling tendencies.
2Measurement precision
If multiple evaluation points are used to assess deviations in each section, then the accuracy of detecting rippling increases, but the complexity of the OPC process increases
Solution Approach 1:
By dividing the image into sections and using multiple evaluation points within each section, the patent achieves comprehensive coverage of the feature landscape. This segmented approach maintains high measurement precision while managing computational complexity through localized analysis rather than global processing.
Solution Approach 2:
The patent employs multiple evaluation methods (minimum, maximum, middle, mean, median) that represent different parameter change strategies. These varied approaches allow the system to adapt to different section characteristics and rippling patterns, improving detection accuracy while providing flexible computational pathways.
3Shape
If corner sections are treated with special modification strategies, then the smoothness of corner features improves, but the overall processing time increases
Solution Approach 1:
The patent applies specialized modification strategies specifically to corner sections where rippling problems are most severe. This localized quality approach ensures that computational resources are concentrated on the most problematic areas, improving corner feature smoothness while minimizing unnecessary processing of already-well-behaved sections.
Solution Approach 2:
By segmenting corner sections from the rest of the image and applying targeted modification strategies, the patent efficiently addresses the specific rippling issues at corners without requiring exhaustive processing of the entire image, thus reducing overall processing time while maintaining corner quality.
Data Source
AI summary
A method for minimizing rippling of features when imaged on a surface of a substrate using a mask. The method includes the steps of determining a deviation between a first representation of the design and a second representation of an image of the design at each of a plurality of evaluation points for each section of a plurality of sections of the design; determining an amount of modification of the design at each section based on an evaluation of the plurality of evaluation points; and modifying the design at each section by the amount determined in the previous step.