Defect Coordinate Calibration for Accurate Killer Defect Indexing
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Solution Overview
Problem
In semiconductor manufacturing, the identification of real open or short circuit failure defects is challenging due to limited defect image sampling from Scanning Electron Microscopes, leading to poor yield improvement efficiency and increased costs, exacerbated by systematic and random defects caused by equipment precision deviations and complex design layout patterns.
Innovation Solution
A smart defect calibration and classification system that uses integrated circuit design layout data and Critical Area Analysis to calibrate defect sizes and coordinates, enabling precise identification of killer defects by converting defect images onto corresponding design layout patterns and calculating a Killer Defect Index.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If defect inspection is performed using SEM and optical microscope to obtain defect images, then defect detection capability is improved, but coordinate deviation and size measurement accuracy deteriorate due to equipment precision limitations
Solution Approach 1:
The patent introduces design layout patterns as an intermediary reference system. By overlaying defect images with corresponding design layout patterns, the system establishes a coordinate transformation relationship that serves as a mediator between the inspection equipment coordinate system and the design coordinate system, enabling accurate defect localization and size measurement despite equipment precision limitations
Solution Approach 2:
The patent transforms defect data by changing coordinate systems and measurement parameters. It converts defect coordinates from the inspection equipment's coordinate system to the design layout's coordinate system through calibration, and adjusts size measurement parameters to account for magnification differences between SEM/optical microscope and defect inspection tool, thereby improving measurement accuracy
2Productivity
If a small number of defect images (50-200) are selected for inspection testing due to limited throughput, then processing time is reduced, but the ability to identify real open/short circuit failure defects deteriorates
Solution Approach 1:
The patent applies local quality by focusing inspection resources on critical areas. It overlays defect images with design layout patterns to identify defects located in critical circuit areas, and prioritizes these 'killer defects' for detailed inspection, rather than treating all defects uniformly. This enables reliable identification of failure-causing defects within limited sampling constraints
Solution Approach 2:
The patent performs preliminary classification by calculating a Killer Defect Index for each defect before detailed inspection. This preliminary action ranks defects by their potential to cause failures, allowing the inspection system to prioritize the most critical defects and achieve reliable failure identification with fewer samples
3Speed
If defect size data from defect inspection tool is used directly for Critical Area Analysis, then analysis speed is improved, but accuracy deteriorates due to size deviation between inspection tool and SEM/optical microscope measurements
Solution Approach 1:
The patent transforms defect size parameters by applying calibration factors that account for the systematic size deviation between defect inspection tools and SEM/optical microscope measurements. This parameter transformation corrects the measured sizes while maintaining the efficiency of automated analysis
4Ease of manufacture
If coordinate conversion from defect image to design layout pattern is performed without calibration, then processing simplicity is maintained, but coordinate accuracy deteriorates due to equipment precision deviation
Solution Approach 1:
The patent performs preliminary calibration by establishing coordinate transformation parameters between defect inspection tool and design layout pattern before actual defect analysis. This preliminary action creates a calibrated coordinate system that maintains both accuracy and ease of use in subsequent defect conversions
Data Source
AI summary
A smart conversion and calibration of the defect coordinate, diagnosis, sampling system and the method thereof for manufacturing fab is provided. The intelligent defect diagnosis method includes receiving pluralities of defect data, design layout data, analyzing the defect data, design layouts, by a Critical Area Analysis (CAA) system. This method utilizes the precisely calibrated coordinate, the defect layout pattern, and the higher accurate calibrated defect size value. So, a more precise killer defect index can be generated with calibrated coordinate deviation calibration and defect size deviation calibration. When judging a defect relating to short circuit or open circuit failure probability, the defect failure result is more accurate and less incorrect judgment.