Defect Inspection Device With Dual Illumination Paths
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Solution Overview
Problem
Current defect inspection devices require multiple inspections with different illuminations for samples with varying patterns, leading to increased inspection time and complexity due to the need for repeated adjustments and movement of the inspection stage.
Innovation Solution
A defect inspection device is designed with a polarizing beam splitter to branch light into two optical paths with collective lenses of different focal distances, generating two distinct illuminations that can be applied simultaneously to different areas of the inspection sample, allowing for concurrent inspection of patterns with different optimal illuminations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple inspections with different illuminations are performed sequentially, then detection capability for various patterns is improved, but inspection time and operational complexity increase
Solution Approach 1:
The illumination optical system is segmented into multiple independent illumination systems, each providing a different illumination condition (e.g., different NA1 values). This allows simultaneous projection of multiple illumination patterns onto different regions of the inspection sample, eliminating the need for sequential inspections and reducing inspection time while maintaining detection capability for various pattern types
Solution Approach 2:
The patent transitions from sequential temporal dimension (one illumination at a time) to spatial dimension by dividing the inspection sample into multiple inspection regions. Each region receives a different illumination condition simultaneously through corresponding illumination systems, allowing parallel inspection across multiple areas with optimized illumination for each pattern type
2Measurement precision
If multiple inspections with different illuminations are performed sequentially, then detection capability for various patterns is improved, but operational complexity increases due to repeated adjustments and stage movement
Solution Approach 1:
The inspection system is segmented into multiple independent inspection channels, each with its own illumination system and imaging path. This segmentation allows each channel to operate independently with optimized illumination for specific pattern types, eliminating the need for repeated adjustments and stage movements required in sequential inspection methods
Solution Approach 2:
Multiple illumination systems and inspection channels are merged into a single integrated inspection device. The combined system simultaneously inspects multiple regions of the sample with different illumination conditions, reducing operational complexity by eliminating repeated setup and adjustment procedures while maintaining high detection capability
3Device complexity
If conventional optical systems are used with single illumination, then device complexity is low, but inspection efficiency for multiple pattern types decreases
Solution Approach 1:
The optical system is segmented into multiple illumination systems with different numerical apertures (NA1) that can be independently controlled. Each illumination system projects light through the same objective lens onto different regions of the inspection sample, enabling efficient inspection of multiple pattern types without requiring complex mechanical reconfiguration or additional expensive components like microlens arrays
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 simultaneous inspection of multiple areas with different illuminations, reducing inspection time and complexity while maintaining high detection capability without the need for extensive alterations to conventional optical systems or increased use of expensive microlens arrays.
Implementation Method 1
a first beam splitter configured to branch light from the light source into a first optical path and a second optical path
Data Source
AI summary
According to one embodiment, a defect inspection device includes a first beam splitter configured to branch light into a first optical path and a second optical path, a first optical system on the first optical path, a second optical system on the second optical path, a first aperture configured to form an illumination field of an inspection sample by light from the first optical system, a second aperture configured to form an illumination field of the inspection sample by light from the second optical system, and a third optical system configured to illuminate, with a first illumination, an image of the first aperture on a first area of the inspection sample, and to illuminate, with a second illumination, an image of the second aperture on a second area of the inspection sample.