Pattern Search Grouping by Surrounding Context for Inspection
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Solution Overview
Problem
Current pattern searching methods in IC design fail to accurately account for variations in neighboring structures, leading to inconsistent inspection sensitivity and defect detection across different pattern locations on a specimen, as they do not effectively leverage the knowledge of surrounding patterns.
Innovation Solution
A system and method that includes an inspection subsystem with an energy source and detector, coupled with computer subsystems capable of searching for target patterns and separating instances based on surrounding patterns within a predefined window, allowing for different combinations of target and surrounding patterns to be grouped and analyzed separately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single inspection sensitivity is used for all sites of a given pattern type, then the inspection process is simplified and faster, but the detectability of defects varies across different locations due to varying neighboring pattern densities and geometries
Solution Approach 1:
The patent segments the inspection process by dividing pattern instances into different groups based on their neighboring pattern characteristics (density, geometry, spacing). This segmentation allows each group to be inspected with optimized sensitivity settings tailored to its specific context, resolving the contradiction between using a single simplified inspection setting and achieving consistent defect detectability across diverse pattern environments.
Solution Approach 2:
The patent applies local quality by assigning different inspection sensitivity parameters to different groups of pattern instances based on their local neighboring context. Each group receives inspection settings optimized for its specific surrounding pattern characteristics, ensuring high defect detectability in each local region while maintaining overall process efficiency through systematic classification.
2Device complexity
If pattern search is based only on the target pattern geometry without considering surrounding patterns, then the search is simpler and faster, but the results cannot be effectively used for optimized inspection and yield analysis
Solution Approach 1:
The patent extends the pattern search from considering only the target pattern geometry (2D spatial matching) to including the surrounding pattern context by adding neighboring pattern characteristics as additional dimensions for classification. This dimensional expansion enables grouping of pattern instances based on their local environment, preserving valuable contextual information for downstream inspection and yield analysis without excessively complicating the search process.
3Measurement precision
If different inspection settings are used for each pattern location based on surrounding patterns, then defect detection accuracy is improved, but the inspection process becomes more complex and time-consuming
Solution Approach 1:
The patent performs preliminary classification of pattern instances into different groups based on their neighboring pattern characteristics before the actual inspection process. This preliminary action organizes the complexity by pre-defining groups with optimized inspection settings, so that during the actual inspection, the system only needs to apply pre-determined settings to each group rather than making complex decisions in real-time, thereby reducing inspection process complexity while maintaining high detection accuracy.
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 enhances inspection sensitivity and defect detection by considering the larger context of surrounding patterns, optimizing inspection settings and improving the accuracy of pattern grouping and classification, thereby reducing noise and improving yield relevance.
Implementation Method 1
The energy source is configured to generate energy that is directed to a specimen
Implementation Method 2
The detector is configured to detect energy from the specimen and to generate output responsive to the detected energy
Data Source
AI summary
Methods and systems for finding patterns in a design for a specimen are provided. One system includes one or more computer subsystems configured for searching for a target pattern in a design for a specimen to thereby find multiple instances of the target pattern in the design. The one or more computer subsystems are also configured for separating the multiple instances of the target pattern into different groups based on information for surrounding patterns within a predefined window around the target pattern such that each of the different groups corresponds to a different combination of the target pattern and the surrounding patterns.