Defect Inspection Masking Common Position Segmentation
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Solution Overview
Problem
Existing defect inspection devices struggle to prevent false defects and achieve high sensitivity due to pattern-dependent settings, which lead to the misidentification of real defects as false defects, especially caused by color unevenness from crystal grains in semiconductor integrated circuits.
Innovation Solution
A defect inspection device with a light source, detector, scanning units, and a mask position setting mechanism that compares detection signals with a threshold, sets a common mask position across unit inspection regions, and adjusts the mask position based on comparison results to differentiate between real and false defects, regardless of the sample pattern, using multiple beams and merge processing to accurately measure defect sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a threshold is set to detect defects based on reflected light intensity, then defect detection sensitivity is improved, but false defects increase due to color unevenness from crystal grains
Solution Approach 1:
The inspection field is divided into multiple unit inspection regions, and the common position among these regions is identified as the mask position. This segmentation allows the system to distinguish between uniform background patterns (crystal grains) and actual defects by comparing signal characteristics across segmented regions.
Solution Approach 2:
A mask position is introduced as an intermediary element that represents the common position across multiple unit inspection regions. This mask position serves as a reference to identify and exclude false defects caused by crystal grain color unevenness while maintaining defect detection sensitivity.
2Reliability
If mask position is set based on sample pattern, then false defects are reduced, but the inspection becomes complex and pattern-dependent
Solution Approach 1:
The mask position is defined as the common position across multiple unit inspection regions, making it universal and independent of specific sample patterns. This universal definition allows the same mask position setting to be applied to different samples without requiring pattern-specific analysis, simplifying the inspection process.
3Reliability
If a large mask position area is used, then false defects are effectively masked, but real defects may be erased
Solution Approach 1:
The mask position is precisely defined as the common position across multiple unit inspection regions, creating a localized mask area that targets false defects without excessively expanding to cover real defects. This local quality approach ensures minimal impact on real defect detection while effectively masking false defects.
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 solution effectively reduces the occurrence of false defects, increases inspection sensitivity, and allows for accurate detection and measurement of real defects by setting mask positions independently of the sample pattern, thereby enhancing the reliability of defect inspection.
Implementation Method 1
a light source that illuminates a sample; a detector that receives light from an illuminated region of the sample
Data Source
AI summary
A defect inspection device according to one aspect of the present invention includes a light source, a detector that receives light from an illuminated region of a sample, a stage that changes a relative position between light from the light source and the sample in order to sequentially inspect a plurality of unit inspection regions, a comparator that compares a detection signal output from the detector with a threshold according to scanning in the stage, a mask position setting unit that sets a common position of the plurality of unit inspection regions as a mask position in order to mask the common position when the plurality of unit inspection regions are sequentially inspected, and a defect detection unit that detects a defect based on a comparison result in the comparison unit in another region than the mask position.