Pattern Inspection Device Simulating Electron Beam Images
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Solution Overview
Problem
Existing pattern inspection technologies fail to accurately simulate electron beam images of resist patterns on wafers from design data, particularly neglecting brightness differences between patterns and backgrounds, and lack necessary parameters for generating realistic simulated images, which hinders high-accuracy defect detection.
Innovation Solution
A pattern inspection device and method that includes an imaging unit, a simulated electron beam image generation unit using design data-based parameters, and an inspection unit for comparing real and simulated electron beam images, accounting for brightness differences and edge characteristics to enhance defect detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional die-to-die inspection is used to compare neighboring dies, then inspection speed is maintained, but systematic defects such as line width deviation and deformed tip shape cannot be detected
Solution Approach 1:
The patent creates a simulated electron beam image as a copy of what the real image should look like based on design data. This simulated image serves as a reference for comparison, enabling detection of systematic defects that would be present in all dies. The simulation copying approach allows die-to-database inspection instead of die-to-die comparison.
Solution Approach 2:
The patent applies parameter changes by adjusting simulation parameters (beam current, accelerating voltage, interaction volume) to match real electron beam imaging conditions. This enables accurate generation of simulated images that can be compared with real images, improving defect detection while maintaining inspection feasibility.
2Adaptability or versatility
If optical inspection simulation method is applied to electron beam images, then general simulation framework is provided, but brightness differences between pattern and background are not accurately represented
Solution Approach 1:
The patent applies local quality by assigning different brightness characteristics to different regions of the image. Specifically, it models the brightness difference between pattern areas and background areas using separate parameters (pattern brightness, background brightness, and their ratio). This local differentiation enables accurate representation of electron beam image characteristics.
Solution Approach 2:
The patent changes parameters by introducing electron beam-specific parameters (beam current, accelerating voltage, interaction volume) and brightness parameters (pattern brightness, background brightness, brightness ratio) to the simulation model. These parameter adjustments transform the optical inspection simulation framework into an accurate electron beam image simulation method.
3Productivity
If simple image comparison is used without considering edge characteristics, then processing speed is maintained, but inspection accuracy is insufficient for detecting subtle defects
Solution Approach 1:
The patent applies segmentation by dividing the image into distinct components: pattern areas, background areas, and edge portions. By separating edge detection from general image comparison and applying specific edge analysis techniques, it enhances defect detection precision without significantly impacting processing speed.
Solution Approach 2:
The patent changes parameters by incorporating edge-specific parameters (edge direction, edge brightness, edge blur) into the simulation and comparison process. These parameter enhancements improve the ability to detect subtle defects at pattern edges while maintaining efficient processing through optimized calculation methods.
Data Source
AI summary
Provided is a pattern inspection device for accurately simulating an electron beam image of a circuit pattern on a wafer from design data, and implementing high-precision defect detection based on the comparison between the simulated electron beam image and a real image. A pattern inspection device comprises: an image capturing unit for capturing an electron beam image of a pattern formed on a substrate; a simulated electron beam image generation unit for generating a simulated electron beam image using a parameter indicating the characteristics of the electron beam image on the basis of design data; and an inspection unit for comparing the electron beam image of the pattern, which is the image captured by the image capturing unit, and the simulated electron beam image generated by the simulated electron beam image generation unit, and inspecting the pattern on the substrate.