Charged Particle Beam Device Selective Scanning Trench Vias
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Solution Overview
Problem
The detection efficiency of electrons emitted from the bottom of patterns with large aspect ratios, such as via bottoms, is low in charged particle beam devices like scanning electron microscopes, making it difficult to perform high accuracy measurements and inspections, especially in semiconductor devices with Cu wiring.
Innovation Solution
A charged particle beam device with a deflector and detector system that selectively scans and detects dark regions within images, allowing for precise control of the scanning line direction and region to enhance the detection of features within trenches and vias, improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the beam is scanned over a wide region including a via, then the overall image can be captured, but the delicate contrast of a low luminance region such as the bottom of the via is buried in a high luminance region, making it difficult to perform high accuracy measurement
Solution Approach 1:
The patent divides the scan region into multiple segments based on luminance characteristics. A first scan region with a first scan rate covers a wider area including high luminance regions, while a second scan region with a second scan rate (higher than the first) focuses on low luminance regions like via bottoms. This segmentation allows the system to capture overall structure while maintaining measurement precision in critical low-signal areas by allocating more scanning resources there.
2Illumination intensity
If the irradiation amount of the low luminance region is improved to increase its luminance relative to the high luminance region, then the contrast of the low luminance region improves, but the significant difference in signal detection efficiency between the sample surface and via bottom remains, preventing high accuracy measurement
Solution Approach 1:
The patent changes the scan rate parameter as a function of position and luminance characteristics. By setting a higher scan rate for low luminance regions and a lower scan rate for high luminance regions, the system effectively adjusts the irradiation amount dynamically. This parameter change compensates for the inherent detection efficiency differences without requiring physical modification of the detection system, enabling high accuracy measurement of via bottoms while maintaining overall image quality.
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 configuration enables high accuracy detection and measurement of features within trenches and vias, improving throughput by concentrating electron beam irradiation on target areas and reducing unnecessary irradiation, thus addressing the low detection efficiency of electrons from via bottoms.
Implementation Method 1
a deflector for causing a charged particle beam emitted from a charged particle source to perform a scan
Implementation Method 2
a detector for detecting a charged particle obtained based on the scanning of the charged particle beam
Data Source
AI summary
The objective of the present invention is to provide a charged particle beam device for setting, from an image of a trench-like groove or a pit, device conditions for finding a hole or the like provided in the trench or the pit, or measuring a hole or the like provided inside the trench or the like with high accuracy. In the present invention, a charged particle beam device comprises: a deflector for causing a charged particle beam emitted from a charged particle source to perform a scan; a detector for detecting a charged particle obtained on the basis of the scanning of the charged particle beam; and a computation processing device for generating an image on the basis of the output of the detector. In the charged particle beam device, the computation processing device specifies, from within the generated image, a relatively dark region with respect to other parts thereof, and controls the deflector in such a manner that the charged particle beam selectively scans a sample position corresponding to the dark region.