Optical Mode Alignment for Semiconductor Inspection Accuracy
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Solution Overview
Problem
Current optical mode selection methods for semiconductor inspection systems are limited in their ability to achieve design-based care area placement accuracy and overlay of design data onto inspection images, leading to potential misplacements and reduced sensitivity, especially when defects are near the edge of memory device areas.
Innovation Solution
A system and method that includes an inspection subsystem with a computer configuration to set and alter parameters across multiple modes without changing the specimen position, allowing for design-based alignment and accurate signal box placement across all modes, ensuring consistent defect detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If design-based alignment is performed for every mode in optical mode selection, then design-based care area placement accuracy is improved, but processing time and system complexity increase
Solution Approach 1:
The patent performs design-based alignment for only the base test mode first, then uses this aligned reference to determine care area positions for all other modes. This preliminary alignment action eliminates the need to perform full alignment processing for every mode, thereby reducing overall complexity while maintaining design-based placement accuracy.
Solution Approach 2:
The aligned care areas from the base test mode serve multiple functions: they provide the reference framework for the base mode itself and simultaneously determine the care area positions for all other inspection modes. This multi-functional use of the base mode alignment reduces redundant processing.
2Measurement precision
If design-based alignment is performed for every mode, then overlay accuracy is improved, but inspection time increases
Solution Approach 1:
The patent performs the time-consuming design-based alignment operation only once for the base test mode before the inspection process begins. This preliminary alignment establishes the reference framework that enables rapid care area determination for all subsequent modes without requiring repeated alignment operations.
Solution Approach 2:
Instead of performing full alignment operations for each mode, the patent creates a reference copy from the base mode alignment and uses this reference to determine care areas for all other modes. This copying approach maintains overlay accuracy while eliminating redundant computational work.
3Reliability
If design-based care areas are used for all modes, then defect detection reliability is improved, but system configuration complexity increases
Solution Approach 1:
The patent establishes the design-based care area reference framework in advance during base mode alignment. Once this reference is established, all other modes can inherit the same reliable care area positions without requiring complex individual configuration for each mode, thereby maintaining high detection reliability.
Solution Approach 2:
The patent maintains consistent care area parameter definitions across all modes by referencing the base mode alignment results. This parameter consistency approach ensures reliable defect detection while simplifying mode configuration, as modes only need to specify their optical parameters rather than redefining care areas.
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 enables design-based accuracy and overlay for every mode, improving signal box placement accuracy and sensitivity, particularly for defects near memory device edges, thereby enhancing the detection of defects with higher reliability.
Implementation Method 1
The energy source is configured to generate energy that is directed to a specimen by the inspection subsystem
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 selecting one or more modes of an inspection subsystem or system for inspection of a specimen are provided. The systems described herein are configured to acquire output for all of the modes to be considered at a location of a known defect on the specimen by aligning output, which is generated at the location with a mode known to generate output in which patterned features on the specimen are resolved to a degree that allows the output to be aligned to design data, with the design data for the specimen to identify the location with substantially high accuracy and then without moving the field of view of the inspection subsystem or system from that location, acquiring the output for all other modes. All of the acquired output can then be used to select mode(s) for inspection of the specimen or another specimen of the same type.