Multi-Angle Defect Inspection with Filtered Signal Separation
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Solution Overview
Problem
Existing defect inspection apparatuses face ambiguity in scattering distribution due to the integration of detection signals, complicating data processing and obscuring defect information.
Innovation Solution
A defect inspection apparatus with a sample stage, illumination optical system, scanning device, detection optical systems, sensors, and signal processing device that generates integrated, filtered, and separated signal groups to reduce ambiguity in scattering distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a plurality of detection signals are integrated to simplify data processing, then data processing complexity is reduced, but scattering distribution of illumination scattered light becomes ambiguous
Solution Approach 1:
The patent divides the scattered light detection into multiple angular regions (front scattering region, side scattering region, back scattering region) with separate detection optical systems. Each region is detected independently and then integrated only for specific defect types, preserving scattering distribution information while enabling simplified processing for particular defect categories.
2Measurement precision
If multiple detection optical systems are arranged in different directions to detect scattered light simultaneously, then detailed defect information is obtained, but data processing becomes complicated
Solution Approach 1:
The detection system is segmented into multiple optical systems positioned at different angular positions (front, side, back scattering directions). Each optical system captures specific scattering characteristics, allowing detailed defect information to be obtained while enabling selective integration strategies that simplify processing for specific defect types.
Solution Approach 2:
Different detection optical systems are assigned to detect scattered light in different angular regions, with each system optimized for its specific detection direction. This local specialization allows the system to capture comprehensive scattering distribution information while enabling targeted data processing for different defect categories.
3Productivity
If detection signals from multiple sensors are integrated, then the number of signals is reduced, but ambiguity in scattering distribution increases
Solution Approach 1:
The patent implements segmentation by maintaining separate detection channels for different scattering regions (front, side, back) and selectively integrating signals based on defect type. This approach improves processing efficiency for specific defects while preserving scattering distribution clarity through targeted integration rather than universal integration of all signals.
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 effectively reduces ambiguity in scattering distribution, enhancing the clarity and accuracy of defect detection by integrating and filtering detection signals.
Implementation Method 1
an illumination optical system for irradiating the sample placed on the sample stage with illumination light
Implementation Method 2
a plurality of detection optical systems for collecting illumination scattered light from a surface of the sample
Implementation Method 3
a plurality of sensors for converting the illumination scattered light collected by the corresponding detection optical systems into electrical signals and outputting detection signals
Data Source
AI summary
Provided is a defect inspection apparatus including a plurality of detection optical systems for collecting illumination scattered light from the surface of a sample, a plurality of sensors for converting the illumination scattered light collected by the corresponding detection optical systems into electrical signals and outputting detection signals, and a signal processing device for processing the detection signals input from the plurality of sensors, wherein the signal processing device generates a first signal group including an integrated signal obtained by adding a plurality of detection signals in a predetermined combination based on a group of detection signals input from the plurality of sensors, generates a second signal group by performing the filtering processing on each signal that configures the first signal group, generates a third signal group including separated signals separated according to a predetermined rule from the signal corresponding to the integrated signal based on the second signal group, and detects or classifies defects based on the third signal group to store defect inspection data in a memory.