Defect Classification via Multi-Angle Scattering Analysis
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Solution Overview
Problem
Current semiconductor inspection systems face challenges in detecting and classifying small defects on substrates due to limitations in sensitivity and throughput, particularly with methods like Energy-Dispersive X-Ray Spectrometry and Raman spectroscopy, which struggle with small particles and require long signal integration times.
Innovation Solution
The development of an inspection system that utilizes a narrowband illumination source to measure defect scattering characteristics such as scattering phase, intensity, and absorption, employing phase shifting phase contrast imaging and multiple detection modes to classify defects based on their material composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional inspection methods (Energy-Dispersive X-Ray Spectrometry, Raman spectroscopy) are used to detect small defects, then material classification capability is provided, but sensitivity and throughput deteriorate due to long signal integration times
Solution Approach 1:
The patent changes the detection parameter from conventional spectroscopic methods to scattering angle measurement. By measuring the angular distribution of scattered light at multiple angles simultaneously, the system achieves both high sensitivity for small particles and high throughput without requiring long integration times.
Solution Approach 2:
The patent introduces a new measurement dimension by measuring scattering at multiple angles simultaneously rather than relying on single-angle spectroscopy. This multi-angle approach enables parallel extraction of material composition information, thereby improving throughput while maintaining sensitivity.
2Adaptability or versatility
If conventional inspection methods are used, then material classification is achieved, but detection capability for small particles deteriorates
Solution Approach 1:
The patent changes from spectroscopic parameter measurement to scattering angle parameter measurement. The angular distribution of scattered light provides material-specific signatures that enable both small particle detection and material classification simultaneously.
Solution Approach 2:
The patent segments the scattering pattern into multiple angular components, with each angle providing independent material information. This segmentation allows simultaneous detection of small particles and classification of material composition through multi-angle analysis.
3Device complexity
If single detection mode is used, then system simplicity is maintained, but defect classification accuracy deteriorates
Solution Approach 1:
The patent adds the dimension of scattering angle to the detection system. By measuring at multiple angles simultaneously, the system gains additional classification information without requiring complex sequential measurement procedures, thus improving accuracy while keeping the system relatively simple.
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 sensitive and high-throughput detection and classification of defects, including small particles, by efficiently utilizing spectral energy and providing accurate material identification suitable for semiconductor fabrication environments.
Implementation Method 1
the radiation emanating from the sample includes radiation specularly reflected by the sample and radiation scattered by the sample
Implementation Method 2
radiation specularly reflected by the sample
Implementation Method 3
a phase control device to introduce two or more different selected phase offsets between the radiation specularly reflected by the sample and the radiation scattered by the sample
Data Source
AI summary
A inspection system includes an illumination source to generate an illumination beam, focusing elements to direct the illumination beam to a sample, a detector, collection elements configured to direct radiation emanating from the sample to the detector, a detection mode control device to image the sample in two or more detection modes such that the detector generates two or more collection signals based on the two or more detection modes, and a controller. Radiation emanating from the sample includes at least radiation specularly reflected by the sample and radiation scattered by the sample. The controller determines defect scattering characteristics associated with radiation scattered by defects on the sample based on the two or more collection signals. The controller also classifies the one or more particles according to a set of predetermined defect classifications based on the one or more defect scattering characteristics.