Fluorescence Microscopy Metrology for LER and Nanoparticle Detection
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Solution Overview
Problem
Existing semiconductor metrology techniques face challenges in accurately measuring line edge roughness (LER) and power spectral density (PSD) and detecting nanoparticle defects, particularly due to limitations in resolution and the need for vacuum conditions in scanning electron microscopy (SEM), which complicates the inspection of micro-structures and defects.
Innovation Solution
A fluorescence microscopy metrology system utilizing super-resolution fluorescence microscopy, capable of measuring LER and PSD, and automatically detecting nanoparticle defects, by employing multiple light sources and image processing algorithms like Canny and strel algorithms to analyze semiconductor patterns and structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If scanning electron microscopy (SEM) is used for measuring LER and detecting nanoparticle defects, then measurement capability is provided, but vacuum conditions are required which complicates inspection and reduces productivity
Solution Approach 1:
The patent replaces the mechanical vacuum-based SEM system with an optical fluorescence microscopy system that operates in ambient conditions. The fluorescence microscopy system uses light excitation and detection rather than electron beams, eliminating the need for vacuum chambers and complex mechanical systems, thereby improving productivity while maintaining measurement capability
Solution Approach 2:
The patent changes the fundamental operating parameters from electron beam physics (requiring vacuum) to optical fluorescence physics (operating in ambient conditions). By using fluorescent materials that emit light when excited by specific wavelengths, the system achieves LER measurement without vacuum requirements, resolving the contradiction between measurement precision and productivity
2Ease of operation
If traditional optical microscopy is used for inspection, then operation simplicity is maintained, but resolution is limited by the diffraction limit of light
Solution Approach 1:
The patent changes the operational parameters of optical microscopy by using stochastic photo-switching of fluorescent molecules instead of continuous illumination. This allows the system to overcome the diffraction limit through temporal separation of signals, achieving super-resolution (sub-20 nm) while maintaining the simplicity of optical operation
Solution Approach 2:
The patent employs periodic photo-switching of fluorescent molecules between on and off states using controlled illumination sequences. This temporal modulation allows individual molecule localization with precision beyond the diffraction limit, achieving super-resolution imaging while keeping the optical system relatively simple to operate
3Measurement precision
If super-resolution fluorescence microscopy is used to achieve sub-20 nm resolution, then measurement precision is improved, but complex image analysis is required to extract LER and PSD data
Solution Approach 1:
The patent implements automated image analysis algorithms that automatically extract LER and PSD measurements from super-resolution fluorescence images without requiring manual intervention. The system performs stochastic optical reconstruction, edge detection, and spectral analysis automatically, reducing the perceived complexity for the user while maintaining high measurement precision
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
Enables high-sensitivity, high-resolution optical inspection with sub-20 nm resolution, accurately measuring LER and PSD, and reliably detecting nanoparticles, overcoming the limitations of traditional SEM methods by providing rapid and accurate nanostructure analysis.
Implementation Method 1
an optical system configured to generate first light and second light having different wavelengths, the first light and the second light configured to excite a fluorescent material
Implementation Method 2
the fluorescent material emits light when exposed to light of a specific wavelength
Implementation Method 3
an image detection device configured to detect a fluorescence image corresponding to the received fluorescence
Data Source
AI summary
A fluorescence microscopy metrology system includes an optical system configured to generate first light and second light having different wavelengths, a microscope body configured to irradiate a sample, coated with a fluorescent material, with the first light and the second light received from the optical system, and to receive fluorescence reflected from the sample, an image detection device configured to detect a fluorescence image corresponding to the received fluorescence, and a nanostructure analysis device configured to measure line edge roughness (LER) from the detected fluorescence image, to analyze power spectral density (PSD), or to detect a nanoparticle defect.