TSOM/SHG Nanoscale Imaging for Semiconductor Defect Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor inspection and metrology systems face challenges in detecting and measuring buried defects in gate-all-around (GAA) architectures due to limitations in sensitivity, specificity, processing speed, and capture rate, especially with defects smaller than 10 nanometers and located in high aspect ratio structures.
Innovation Solution
The implementation of through-focus scanning optical microscopy (TSOM) combined with second harmonic generation (SHG) light signals, which provides interface-selective sensitivity and high resolution capabilities, allowing for non-destructive and high-throughput detection and measurement of defects and structural dimensions in complex semiconductor structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional optical microscopy is used for inspecting buried defects in high aspect ratio structures, then the field of view and depth of penetration are improved, but the measurement precision and detection sensitivity deteriorate due to diffraction limits and signal interference
Solution Approach 1:
The patent changes the optical parameters by utilizing second harmonic generation (SHG) signal detection at different wavelengths. The system illuminates with fundamental wavelength light and detects SHG signals at half the wavelength, enabling nanoscale resolution while maintaining deep penetration capability. This parameter transformation resolves the contradiction between field of view and measurement precision.
Solution Approach 2:
The patent introduces through-focus scanning capability that adds the depth dimension to conventional optical imaging. By scanning through multiple focal planes and reconstructing three-dimensional information, the system achieves both deep penetration into high aspect ratio structures and precise defect localization, resolving the contradiction between penetration depth and measurement precision.
2Quantity of substance
If conventional microscopy is used to detect nanoscale defects, then the detection range is improved, but the detection sensitivity deteriorates due to signal interference from surrounding structures
Solution Approach 1:
The patent applies local quality enhancement by detecting SHG signals that are generated specifically at interfaces and boundaries within the semiconductor structure. This interface-selective detection provides localized information about defects while filtering out bulk signal interference, thereby improving detection sensitivity without sacrificing detection range.
Solution Approach 2:
The patent utilizes wavelength transformation through second harmonic generation, where illumination at fundamental wavelength produces detectable signals at half wavelength. This color change enables selective detection of interface features and defects while suppressing background signals from bulk materials, improving signal-to-noise ratio and detection sensitivity.
3Measurement precision
If through-focus scanning is performed to achieve nanoscale resolution, then the measurement precision is improved, but the processing speed and productivity deteriorate
Solution Approach 1:
The patent implements periodic action through automated through-focus scanning that systematically acquires images at multiple focal planes in a repeating sequence. This structured periodic acquisition, combined with efficient image reconstruction algorithms, enables nanoscale precision measurement while maintaining high throughput by processing data in organized batches rather than continuous real-time analysis.
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 and measurement of defects and dimensions in GAA structures by minimizing interference from surrounding structures, enabling accurate identification and classification of defects even at the nanoscale, thereby improving device yield and performance.
Implementation Method 1
through-focus scanning optical microscopy (TSOM) combined with second harmonic generation (SHG) light signals
Data Source
AI summary
Methods and systems for improved detection of defects of interest and measurement of structures buried within complex three dimensional semiconductor structures are described herein. Through-focus scanning optical microscopy (TSOM) using non-linear, second harmonic generation (SHG) light signals emitted from a sample provides interface-selective sensitivity for metrology and inspection of advanced semiconductor structures. A TSOM/SHG system includes a spectral filter to pass collected light at wavelengths corresponding to SHG emission. In some embodiments, a TSOM/SHG system includes an ultrafast, pulsed laser source emitting ultraviolet to near infrared wavelengths to efficiently induce SHG at surface interfaces. The halving of wavelength inherent to SHG enables a doubling of illumination wavelength without penalizing resolution. In a further aspect, a TSOM/SHG measurement system includes an exogenous illumination source, an external electric field source, or both, to induce a DC electric field at one or more interfaces of structures under illumination, thereby enhancing SHG emission.