Wafer Inspection Navigation Accuracy via Alignment Target Segmentation
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Solution Overview
Problem
Current methods for examining semiconductor wafers and similar objects face challenges in accuracy and efficiency due to navigation errors during the inspection process, which can lead to false positives, nuisances, and incomplete defect detection, especially with the increasing complexity and precision demands in manufacturing.
Innovation Solution
The method involves selecting a subset of alignment targets that are closer to the review locations, allowing for reduced navigation errors by using a processor to align the object with these targets, capture images, and apply transformations to ensure accurate defect detection within a specified field of view, thereby enhancing the efficiency and accuracy of the examination process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple alignment targets are used for each review location to ensure accuracy, then navigation precision is improved, but the examination time and process complexity increase significantly
Solution Approach 1:
The patent segments the wafer surface into multiple regions, each associated with a single alignment target. Review locations are grouped by their proximity to alignment targets, allowing the system to process different regions independently. This segmentation enables efficient navigation by reducing the number of alignment operations needed while maintaining adequate precision for each local region.
Solution Approach 2:
The patent applies partial alignment actions by using a single alignment target for multiple review locations within a defined distance threshold. Instead of performing full alignment operations for every review location, the system performs alignment only when necessary (when moving between different alignment target regions), reducing redundant operations while maintaining sufficient navigation accuracy for nearby locations.
2Productivity
If a single alignment target is used for multiple review locations to reduce complexity, then examination efficiency is improved, but navigation accuracy deteriorates due to accumulated errors
Solution Approach 1:
The patent divides the wafer into multiple regions, each with its own alignment target, creating a hierarchical structure where review locations are first grouped by proximity to alignment targets. This segmentation allows the system to use single-target alignment within each region (improving efficiency) while providing multiple alignment targets across the entire wafer (maintaining overall accuracy).
Solution Approach 2:
The patent introduces a distance parameter that defines the maximum distance between a review location and its associated alignment target. By adjusting this parameter, the system can optimize the balance between efficiency (fewer alignment targets) and accuracy (smaller distances reduce error accumulation). This parameter-based approach allows flexible adaptation to different examination requirements.
3Reliability
If alignment targets are placed densely across the wafer to minimize navigation errors, then navigation accuracy is improved, but the device complexity and preparation time increase
Solution Approach 1:
The patent applies local quality by ensuring that within each local region (defined by distance from an alignment target), the navigation reliability is maintained using a single alignment target. The system does not require uniform dense distribution of alignment targets across the entire wafer, but rather provides adequate local quality in each region, reducing overall complexity while maintaining navigation reliability where needed.
Solution Approach 2:
The patent performs preliminary grouping of review locations by their proximity to alignment targets before the actual examination process. This preliminary action organizes the work in advance, allowing the system to navigate efficiently between pre-defined regions without requiring dense alignment target distribution. The preliminary organization reduces the need for complex real-time decision-making during examination.
4Measurement precision
If comprehensive alignment operations are performed for every review location to ensure precision, then defect detection accuracy is improved, but the review process time increases
Solution Approach 1:
The patent performs partial alignment operations only when transitioning between different alignment target regions, rather than performing full alignment operations for every review location. Within each region, the system uses the pre-established alignment to navigate to multiple review locations without repeated alignment, significantly reducing the number of alignment operations while maintaining adequate detection accuracy for nearby locations.
Solution Approach 2:
The patent maintains continuous useful action by keeping the alignment state active across multiple review locations within a region. Instead of interrupting the review process with repeated alignment operations, the system continuously navigates between review locations using the established alignment, maximizing the productivity of each alignment operation and maintaining defect detection accuracy throughout the region.
Data Source
AI summary
Data indicative of alignment targets may be received. Each alignment target may be associated with a target location on an object. Locations of the object to be inspected may be identified. An alignment target from the alignment targets may be selected. Each of the locations may be within a determined distance from the selected alignment target. An indication may be provided to align the object relative to an examination tool for inspecting the locations within the determined distance from the selected alignment target.