Charged Particle Beam Inspection via Dielectric Edge Luminance
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Solution Overview
Problem
Existing charged particle beam apparatuses struggle to detect electrical characteristic defects in semiconductor patterns made of metal or semiconductor materials with high sensitivity due to low luminance changes in response to potential differences, primarily because these materials emit a small amount of secondary electrons.
Innovation Solution
An inspection method that involves scanning a sample with a charged particle beam to acquire a secondary electron image, calculating a feature based on a luminance value of a third region extending from the boundary between a dielectric and conductor regions, and inspecting the electrical characteristic of the pattern based on this feature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage contrast method is used to inspect electrical characteristic defects, then detection capability is improved, but detection sensitivity is insufficient for metal or semiconductor patterns due to low luminance change
Solution Approach 1:
The patent uses the dielectric region as an intermediary to detect the electrical characteristics of the conductor/semiconductor pattern. Instead of directly measuring the low-luminance pattern, the method measures the luminance of the adjacent dielectric region which is influenced by the pattern's potential, thereby indirectly detecting the electrical characteristic with higher sensitivity.
Solution Approach 2:
The patent applies local quality by selecting a specific region (dielectric region adjacent to the pattern) that has different properties (higher secondary electron emission) from the pattern itself. This localized approach allows the measurement to be performed in a region with favorable characteristics while still reflecting the properties of the target pattern.
2Measurement precision
If direct luminance measurement of metal or semiconductor pattern is performed, then inspection process is simple, but detection sensitivity is low due to small secondary electron emission
Solution Approach 1:
The dielectric region serves as a mediator that amplifies the detectable signal. By measuring the luminance of the dielectric region instead of the pattern directly, the method achieves higher detection sensitivity while the additional complexity is minimal (only requires region selection and luminance measurement).
Solution Approach 2:
The patent changes the measurement parameter from direct pattern luminance to adjacent dielectric region luminance. This parameter change exploits the difference in secondary electron emission characteristics between materials, transforming a difficult measurement into an easier one with higher sensitivity.
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
Enhances the detection sensitivity of electrical characteristics in semiconductor patterns by analyzing the luminance change in the dielectric region adjacent to the conductor or semiconductor patterns, thereby improving defect detection accuracy.
Implementation Method 1
The luminance of the SEM image depends on an amount of secondary electrons emitted from the sample
Data Source
AI summary
An inspection method for inspecting an electrical characteristic of a pattern 102 made of a conductor or a semiconductor in a dielectric region 101 on a sample, the inspection method including: scanning the sample with a charged particle beam to acquire a secondary electron image; calculating a feature based on a luminance value of a third region 113 extending from a boundary between a first region 111 and a second region 112 toward the first region and having a higher luminance than the second region, the first region corresponding to the dielectric region and the second region corresponding to the pattern in the secondary electron image; and the electrical inspecting characteristic of the pattern based on the feature.