Charged Particle Beam Device Multi-Detector Signal Synthesis
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Solution Overview
Problem
Existing charged particle beam devices, such as SEMs, face challenges in acquiring high-quality images of multi-layer semiconductor patterns due to insufficient detection of low-layer patterns, which results in low contrast, as reflection/secondary electrons from the low-layer surface are often blocked by the upper layer and cannot reach the detectors.
Innovation Solution
The use of multiple detectors arranged at different locations to detect reflection/secondary electrons, with the synthesis of detected signals controlled by pattern direction and edge strength information from design data or detected images, allowing for flexible image synthesis and improved contrast of low-layer patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single detector is used to detect reflection/secondary electrons, then the device structure is simple, but the detection area is limited and low-layer pattern contrast is poor
Solution Approach 1:
The detection system is segmented into multiple detectors (first reflection electron detector, second reflection electron detector, secondary electron detector) positioned at different locations. Each detector captures electrons from specific angular ranges, collectively covering a wider detection area than a single detector could provide, thereby improving low-layer pattern visibility.
Solution Approach 2:
Detectors are arranged in three-dimensional space around the electron beam axis at different angular positions and elevations. This spatial distribution across multiple dimensions enables comprehensive coverage of reflected and secondary electrons emanating from the sample surface, expanding the effective detection area.
2Measurement precision
If multiple detectors are used to detect electrons from wider areas, then the detection area is improved, but the signal synthesis becomes complex
Solution Approach 1:
The system dynamically adjusts synthesis coefficients based on pattern direction parameters and edge strength parameters. By changing these parameters according to the specific features being observed, the system optimizes the contribution of each detector's signal, improving image quality while managing synthesis complexity through parameter-driven adaptation.
Solution Approach 2:
The signal synthesis process incorporates feedback mechanisms where the detected pattern direction and edge strength information is used to adjust synthesis coefficients. This feedback loop enables the system to automatically optimize image quality by emphasizing signals from detectors that capture relevant features while suppressing noise from less relevant detection angles.
3Measurement precision
If equal weight coefficients are used for signal synthesis, then the processing is simple, but the low-layer pattern contrast is insufficient
Solution Approach 1:
Different synthesis coefficients are applied to signals from different detectors based on their spatial positions and the local pattern characteristics. The system identifies regions with low-layer patterns and applies enhanced weighting to detector signals that are most sensitive to those regions, creating locally optimized contrast enhancement rather than uniform processing.
Solution Approach 2:
The synthesis coefficients are dynamically changed based on detected pattern direction and edge strength parameters. When low-layer patterns are identified, the system adjusts coefficients to emphasize signals from detectors positioned at angles that provide better visibility of those patterns, thereby improving contrast through parameter adaptation.
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 enhances the contrast of low-layer patterns in multi-layer semiconductor images, improving image quality by effectively detecting and synthesizing signals from multiple detectors based on pattern-specific weight coefficients, thereby overcoming the limitations of traditional systems.
Implementation Method 1
Primary electron beam that is emitted from an electron gun are converged by a convergence lens, and scanning is two-dimensionally performed on a sample by using a deflection coil
Implementation Method 2
An electron beam image can be obtained by capturing reflection/secondary electrons by a detector, the electrons being generated from the sample by the electron beam irradiation
Data Source
AI summary
The invention relates to a technique of improving a contrast of a lower-layer pattern in a multi layer by synthesizing detected signals from a plurality of detectors by using an appropriate allocation ratio in accordance with pattern arrangement. In a charged particle beam device capable of improving image quality by using detected images obtained from a plurality of detectors and in a method of improving the image quality, a method of generating one or more output images from detected images corresponding to respective outputs of the detectors that are arranged at different locations is controlled by using information of a pattern direction, an edge strength, or others calculated from a design data or the detected image. In this manner, a detection area of the detected signals can be expanded by using the plurality of detectors, and the image quality such as the contrast can be improved by synthesizing the detected signals by using the pattern direction or the edge strength calculated from the design data or the detected images.