Reticle Haze Detection via Non-Pattern Area Segmentation
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Solution Overview
Problem
Conventional defect inspection apparatuses struggle to detect small haze particles on reticles/masks due to high sensitivity requirements and erroneous detection issues caused by scattered light from complex circuit patterns, leading to inefficiencies and potential yield losses in semiconductor production.
Innovation Solution
A defect inspection apparatus that sets the inspection target area in the non-pattern area, using a light source, light scanning, and photodetector to detect scattered light, allowing for high-sensitivity inspection of small haze particles without erroneous detection, and includes features for calculating haze size and distribution to prevent yield losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high sensitivity inspection is used to detect small haze particles, then detection precision is improved, but erroneous detection increases due to scattered light from pattern areas
Solution Approach 1:
The inspection area is segmented into pattern areas and non-pattern areas. The patent selectively inspects only the non-pattern areas where haze forms, excluding the pattern areas that cause scattered light interference. This segmentation resolves the contradiction by focusing inspection precision where it is needed while avoiding erroneous detections in pattern areas.
Solution Approach 2:
Different inspection strategies are applied to different regions. The patent applies high-sensitivity inspection to non-pattern areas where haze forms, while avoiding or reducing inspection in pattern areas where scattered light causes erroneous detections. This local differentiation resolves the contradiction between detection precision and accuracy.
2Measurement precision
If the entire surface is inspected for haze, then detection completeness is improved, but inspection time increases reducing productivity
Solution Approach 1:
The patent extracts and inspects only the non-pattern areas where haze forms, excluding the pattern areas from the inspection process. This extraction principle resolves the contradiction by reducing inspection scope to only necessary areas, maintaining detection completeness for haze while significantly reducing inspection time and improving productivity.
Solution Approach 2:
Instead of inspecting the entire surface (excessive action), the patent applies partial inspection to only the non-pattern areas where haze actually forms. This partial action principle resolves the contradiction by performing just enough inspection to detect haze without wasting time on pattern areas.
3Device complexity
If conventional inspection apparatus is used for haze inspection, then device simplicity is maintained, but sensitivity is insufficient for small haze particles
Solution Approach 1:
The patent performs preliminary identification of non-pattern areas before inspection. By pre-determining which areas are suitable for haze inspection, the system can use conventional apparatus with simple optics while achieving high sensitivity through intelligent inspection area selection rather than complex hardware.
Solution Approach 2:
The patent introduces an intermediary control mechanism that selects and manages inspection areas. This software-based intermediary coordinates the simple optical components to achieve high sensitivity by directing inspection attention to non-pattern areas, compensating for hardware simplicity with intelligent control.
4Area of stationary object
If pattern areas are included in inspection, then inspection coverage is improved, but scattered light from patterns causes erroneous detections
Solution Approach 1:
The inspection area is segmented into pattern and non-pattern regions. The patent deliberately excludes pattern areas from inspection while covering non-pattern areas where haze forms. This segmentation resolves the contradiction by maintaining adequate coverage for haze detection while eliminating the source of scattered light interference.
Solution Approach 2:
The patent converts the harmful scattered light from pattern areas into a beneficial exclusion criterion. By recognizing that pattern areas produce scattered light interference, the system uses this characteristic to deliberately avoid inspecting those areas, transforming the harmful effect into a guide for selecting appropriate inspection regions.
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
Enables precise and rapid detection of haze in non-pattern areas, preventing yield losses by reducing erroneous detection and improving inspection efficiency, allowing for timely preventative measures such as cleaning or exchanging the reticle/mask.
Implementation Method 1
a photodetector for detecting light diffracted and/or scattered by the inspection target plane as detection light
Implementation Method 2
a photodetector for detecting light diffracted and/or scattered by the inspection target plane as detection light
Data Source
AI summary
The defect inspection apparatus and method for determining an acceptable condition of a reticle/mask member with a pattern area to be developed on a semiconductor device includes determining a non-pattern area and designating an inspection target area within a non-pattern area. Light is scanned across the inspection target area and detected to provide representative signals. The representative signals are processed to define the status of foreign matter including size and location and further compared with predetermined values to determine the acceptability of the mask for continued production purposes.