Substrate Defect Detection via Dual-Region Electron Beam Irradiation
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Solution Overview
Problem
Existing methods for inspecting semiconductor substrates, such as electron microscopes and surface test devices, suffer from poor signal-to-noise ratio and inadequate detection performance, leading to undetected defects that can cause semiconductor devices to malfunction.
Innovation Solution
A method involving the irradiation of electron beams into two regions of a substrate, with secondary electrons emitted from one region being detected to generate an image indicating defects, improving the signal-to-noise ratio and detection capability by increasing the detected electron amount through electrical connection and simultaneous irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional inspection devices (electron microscopes, surface test devices) are used to inspect substrate defects, then the inspection process can be performed, but the signal-to-noise ratio is poor and detection performance is limited
Solution Approach 1:
The substrate is divided into multiple regions (first region, second region, third region) with different inspection methods applied to each. The first region uses conventional inspection, the second region uses the improved electron beam method with higher electron dosage, and the third region uses standard inspection. This segmentation allows optimization of detection precision for different defect types while managing overall inspection efficiency.
Solution Approach 2:
The electron dosage (inspection parameter) is changed between different regions. The second region receives a higher electron dosage than the first and third regions, which improves the signal-to-noise ratio and defect detection precision in areas where defects are more likely to occur or are more critical.
2Measurement precision
If higher electron dosage is used to improve signal-to-noise ratio, then detection precision improves, but inspection time increases
Solution Approach 1:
The substrate inspection is segmented into multiple regions with different electron dosages applied. Only the second region (where defects are most likely or critical) receives high electron dosage for improved precision, while the first and third regions use standard or reduced dosages. This segmentation maintains detection precision for critical areas while reducing overall inspection time.
Solution Approach 2:
Different inspection qualities (electron dosages) are applied to different regions of the substrate based on local defect probability and criticality. The second region receives higher quality inspection (higher electron dosage) while other regions receive standard inspection, optimizing the balance between detection precision and inspection time.
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 detection of defects by improving the signal-to-noise ratio, allowing for clearer identification of defects and increased detection capability, as demonstrated by improved grayscale contrast in defect images.
Implementation Method 1
irradiating an electron beam into a first region of a substrate; irradiating an electron beam into a second region electrically connected to the first region; and detecting secondary electrons emitted from the second region
Data Source
AI summary
A method for detecting defects includes irradiating at least one electron beam into a first region of a substrate, irradiating at least one electron beam into a second region electrically connected to the first region, and detecting secondary electrons emitted from the second region. The electron beam irradiated into the first region may be the same or different from the electron beam irradiated into the second region. Alternatively, different beams may be simultaneously irradiated into the first and second regions. An image generated based on the secondary electrons shows a defect in the substrate as a region having a grayscale difference with other regions in the image.