Multi-Point Plasma Illumination for Higher Inspection Throughput
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Solution Overview
Problem
Existing optical inspection systems face challenges in improving inspection throughput, particularly when using critical illumination with plasma bright points, due to limitations in illumination intensity and detection capabilities.
Innovation Solution
The system employs multiple plasma bright points to illuminate different regions of an object with critical illumination, using elliptical mirrors to direct light fluxes to specific regions, and alternates detection units to capture secondary light, eliminating the need for optical diaphragms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single plasma bright point is used for critical illumination, then the optical system is simple, but the inspection throughput is limited
Solution Approach 1:
The patent divides the illumination function by using multiple plasma bright points (first bright point and second bright point) that independently illuminate different regions of the object. This segmentation allows parallel inspection of multiple regions, thereby improving inspection throughput without requiring a single complex illumination system
2Productivity
If multiple plasma bright points are used to illuminate different regions, then inspection throughput improves, but the device complexity increases
Solution Approach 1:
The patent employs elliptical mirrors that serve dual functions: they both illuminate different object regions with critical illumination and direct the secondary light from those regions to the detection units. This multi-functionality reduces the need for separate illumination and detection optics, thereby limiting the increase in device complexity while maintaining improved throughput
3Manufacturing precision
If optical diaphragms are used to control light flux, then illumination precision is improved, but the device complexity and size increase
Solution Approach 1:
The patent replaces mechanical optical diaphragms with an optical field-based solution using elliptical mirrors. The mirrors use their geometric properties to naturally control and direct light fluxes without requiring mechanical aperture components, thereby maintaining illumination precision while reducing device complexity and size
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 throughput by distributing illumination power across multiple regions and optimizing detection, improving inspection accuracy and efficiency without increasing physical size or complexity.
Implementation Method 1
a first elliptical mirror configured to illuminate a first region of the object with first critical illumination by first illuminating light generated from a first light flux of light from the bright point, and a second elliptical mirror configured to illuminate a second region of the object that differs from the first region of the object with second critical illumination by second illuminating light generated from a second light flux of the light from the bright point
Data Source
AI summary
An inspection apparatus according to the present embodiment includes an optical system configured to illuminate an object with critical illumination using plasma as a bright point, detecting means for detecting secondary light from the object illuminated by the critical illumination, and plasma forming means for forming at least a first bright point and a second bright point as the bright point, in which the optical system is configured to: illuminate a first region of the object with first critical illumination by first illuminating light generated from the first bright point, and illuminate a second region of the object with second critical illumination by second illuminating light generated from the second bright point.