Charged Particle Beam Microscope Image Quality Improvement Using Design Data
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Solution Overview
Problem
Conventional scanning type charged particle beam microscopes face limitations in achieving high image quality due to resolution degradation from diffraction and aberrations, and insufficient Signal-to-Noise Ratio (S/N) without damaging the sample or prolonging imaging time, especially when relying solely on hardware improvements or image processing methods that do not utilize design data or sample characteristic information.
Innovation Solution
The implementation of an image quality improvement method using design data and sample characteristic information to enhance the processing of secondary charged particle images in scanning type charged particle beam microscopes, allowing for precise and efficient area division and emphasis on areas with significant differences between design and sample data, thereby improving image quality and defect detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of charged particle beam is increased to enhance S/N ratio, then the signal-to-noise ratio is improved, but sample damage occurs and imaging time is prolonged
Solution Approach 1:
The patent applies preliminary action by performing image quality improvement processing on the obtained image data before final analysis. The image quality improvement unit processes the raw image data to enhance resolution and S/N ratio through computational methods, allowing the use of lower charged particle beam doses while achieving the required image quality. This preliminary processing step enables defect detection without exposing the sample to high levels of radiation.
2Measurement precision
If hardware improvements are made to charged particle beam microscope to enhance resolution, then resolution is improved to a certain degree, but diffraction aberrations and chromatic/spherical aberrations inevitably degrade resolution
Solution Approach 1:
The patent replaces mechanical/optical improvement approaches with computational image processing methods. Instead of continuously improving hardware to overcome diffraction and aberration limits, the system uses an image quality improvement unit that applies digital processing algorithms to enhance resolution and image quality. This substitution of computational methods for physical improvements allows the system to achieve higher effective resolution without being constrained by physical aberration limits.
3Reliability
If conventional image quality improvement methods are used without design data, then processing is simpler, but sufficient image quality improvement cannot be achieved
Solution Approach 1:
The patent introduces design data as an intermediary element that bridges the sample image and the image quality improvement process. The image quality improvement unit uses design data (such as expected pattern geometries and specifications) as a reference to guide the enhancement process. This intermediary allows the system to achieve superior image quality by comparing actual images against design expectations and selectively enhancing relevant features, while the complexity is managed through automated processing workflows.
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 enables simultaneous high precision and fast processing, effectively emphasizing critical areas and improving the accuracy of defect detection and pattern measurement, leading to enhanced image quality and reliability in semiconductor wafer inspections and pattern analysis.
Implementation Method 1
a charged particle beam irradiation unit to irradiate a focused charged particle beam to a surface of a sample formed with a pattern
Implementation Method 2
a secondary charged particle detection unit to detect secondary charged particles emitted from the sample as the charged particle beam irradiation unit irradiates the charged particle beam to the sample
Data Source
AI summary
Design data and sample characteristic information corresponding to individual areas on the design data are used to perform an image quality improvement operation to make appropriate improvements on image quality according to sample characteristic corresponding to the individual areas on the image, allowing a high speed area division on the image. Further, the use of a database that stores image information associated with the design data allows for an image quality improvement operation that automatically emphasizes portions of the image that greatly differ from past images of the similar design data.