Surface Inspection Apparatus for Defect Detection
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Solution Overview
Problem
Existing surface inspection apparatuses face challenges in separately detecting various types of defects, such as defocus and dose defects, in repetitive patterns due to limited detection sensitivity, which depends on the combination of defect type and detection method used.
Innovation Solution
A surface inspection apparatus employing a combination of first and second measuring units that utilize regular reflection light intensity and polarized state variations to detect defects, with adjustable polarization plates in the light paths to optimize detection sensitivity for different defect types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single detection method is used, then the apparatus structure remains simple, but detection sensitivity for various defect types is insufficient
Solution Approach 1:
The detection system is divided into multiple independent measuring units, each specialized for detecting specific defect types. The first measuring unit detects defects using intensity variation of regular reflection light, while the second measuring unit detects defects using polarized state variation. This segmentation allows each unit to be optimized for its specific detection function, achieving high detection sensitivity for different defect types without requiring a single complex universal detector.
Solution Approach 2:
The apparatus integrates multiple detection functions into a single system that can detect various defect types (defocus defects, dose defects, etc.) using different physical principles. By combining intensity-based detection and polarization-based detection in one apparatus, the system achieves multi-functionality, enabling it to adapt to different defect types while maintaining a unified structural framework.
2Measurement precision
If multiple measuring units are added to detect different defect types, then detection sensitivity improves, but device complexity increases
Solution Approach 1:
Multiple measuring units are merged into a single integrated apparatus with shared optical components and control systems. The first and second measuring units are combined in one apparatus, allowing them to operate simultaneously or sequentially on the same sample. This merging reduces overall system complexity compared to having separate standalone devices for each detection method.
Solution Approach 2:
The apparatus employs adjustable polarization plates that can be dynamically configured based on the detection requirements. The polarization plates can be rotated or adjusted to optimize the detection sensitivity for different defect types, allowing the system to adapt its configuration dynamically rather than requiring fixed, dedicated hardware for each defect type.
3Measurement precision
If polarization plates are made adjustable, then detection sensitivity for different defect types is optimized, but operational complexity increases
Solution Approach 1:
The apparatus changes the polarization state parameter by adjusting the polarization plates to optimize detection sensitivity for different defect types. By modifying the polarization angle or orientation, the system can enhance its sensitivity to specific defect characteristics without changing the fundamental detection mechanism or hardware configuration.
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
The apparatus achieves sufficient detection sensitivity for multiple types of defects, enabling selective detection of defocus and dose defects, and provides information on defect types for real-time exposure adjustments.
Implementation Method 1
measures, based on a intensity of regular reflection light generated from the repetitive patterns, a variation in the intensity caused by a change in shapes of the repetitive patterns
Implementation Method 2
measures, based on a polarized state of the regular reflection light generated from the repetitive patterns, a variation in the polarized state caused by the change in the shapes of the repetitive patterns
Data Source
AI summary
A surface inspection apparatus includes units illuminating repetitive patterns formed on a surface of a suspected substance and measuring a variation in an intensity of regular reflection light caused by a change in shapes of the repetitive patterns, units illuminating the repetitive patterns with linearly polarized light, setting an angle formed between a repetitive direction of the repetitive patterns and a direction of a plane of vibration of the linearly polarized light at a tilt angle, and measuring a variation in a polarized state of the regular reflection light caused by the change in the shapes of the repetitive patterns, and a unit detecting a defect of the repetitive patterns based on the variation in the intensity and the variation in the polarized state of the regular reflection light.