SEM Measurement Merging for Critical Dimension Dispersion
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Solution Overview
Problem
Current scanning electron microscope (SEM) measurement methods face challenges in accurately measuring critical dimensions (CDs) across different positions on a semiconductor wafer, leading to CD dispersion and increased review time due to the need for individual position corrections in each SEM image.
Innovation Solution
The method involves obtaining multiple SEM images from various locations on a wafer, generating a merged SEM image by aligning and merging these images, creating a merged measurement area, and then generating individual measurement areas corresponding to this merged area, allowing for the measurement of critical dimensions and prediction of a representative CD, thereby reducing position dispersion and review time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual position corrections are performed in each SEM image, then measurement accuracy is improved, but review time and operational complexity increase
Solution Approach 1:
The patent merges multiple individual SEM images into a single merged image that contains all measurement areas from different wafer locations. This consolidation allows the reviewer to perform position correction once on the merged image rather than repeatedly correcting each individual image, thereby maintaining measurement accuracy while significantly reducing review time and operational complexity
Solution Approach 2:
The merged image serves multiple functions simultaneously: it displays all measurement areas from different locations, provides a unified reference for position correction, and enables batch processing of critical dimension measurements. This multi-functionality eliminates the need for separate correction operations on each individual image
2Measurement precision
If individual position corrections are performed in each SEM image, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple individual SEM images into a single merged image that contains all measurement areas from different wafer locations. This consolidation allows the reviewer to perform position correction once on the merged image rather than repeatedly correcting each individual image, thereby maintaining measurement accuracy while significantly reducing review time and operational complexity
Solution Approach 2:
The patent extracts all measurement areas from individual SEM images and consolidates them into a single merged image. This extraction process separates the measurement areas from their original individual image contexts, allowing for unified position correction and simplified processing without losing measurement accuracy
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 significantly reduces CD dispersion and review time by correcting the merged measurement area once, improving the accuracy of critical dimension measurements and enhancing the reliability of optical proximity correction modeling.
Implementation Method 1
SEMs are a type of electron microscope that generates an SEM image by scanning the surface of a sample through electron beam irradiation
Data Source
AI summary
There are provided a scanning electron microscope (SEM) measurement method and/or apparatus that reduce critical dimension (CD) dispersion according to position correction of a measurement area in CD measurement in several SEM images of the same pattern. The SEM measurement method includes obtaining individual SEM images at a plurality of locations on a wafer via an SEM, generating a merged SEM image by aligning the individual SEMs and merging the individual SEM images, generating a merged measurement area in the merged SEM image, generating, in the individual SEM images, individual measurement areas corresponding to the merged measurement area, and measuring individual critical dimensions (CDs) in the individual measurement areas.