Related Experiment Video
Updated: Feb 13, 2026
08:48
Writing Bragg Gratings in Multicore Fibers
Published on: April 20, 2016
8.7K
Metrology of nanoscale grating structures by UV scatterometry
Optics Express
|March 10, 2018
Summary
Goniometric scatterometry precisely reconstructs 25 nm grating profiles on silicon wafers. This advanced technique offers accurate cross-section analysis, validated by scanning electron microscopy (SEM).
Area of Science:
- Optics and Photonics
- Materials Science
- Nanotechnology
Background:
- Gratings are crucial optical components.
- Characterizing nanoscale gratings requires high precision.
- Existing methods have limitations in profile reconstruction.
Purpose of the Study:
- To demonstrate goniometric scatterometry for nanoscale grating analysis.
- To reconstruct the complete cross-section profile of gratings.
- To introduce and validate a novel geometry parameterization.
Main Methods:
- Goniometric scatterometry measurements at 266 nm wavelength.
- Measurements performed in four configurations with parallel data evaluation.
- Novel geometry parameterization and co-variance analysis.
Main Results:
- Accurate reconstruction of grating cross-section profiles down to 25 nm linewidth.
- Demonstration of a new parameterization overcoming previous limitations.
- Excellent qualitative agreement with cross-section scanning electron microscope (SEM) images.
Conclusions:
- Goniometric scatterometry is effective for nanoscale grating characterization.
- The novel parameterization enhances the reliability of profile reconstruction.
- The method provides a valuable, non-destructive alternative to SEM for grating analysis.
Related Concept Videos
01:30UV–Vis Spectrum
2.2K
When light passes through a substance, a portion of the light is absorbed while the remaining light is reflected or transmitted. If the molecule absorbs light between the wavelengths of 180–400 nm range, the UV spectrum is obtained, and if it absorbs light in the 400–780 nm wavelength range, the visible spectrum is obtained.
The UV–Vis spectrum of a molecule is the plot of its absorbance versus wavelength. The plot is drawn by taking molar...
The UV–Vis spectrum of a molecule is the plot of its absorbance versus wavelength. The plot is drawn by taking molar...
2.2K
01:14UV–Vis Spectrometers
3.8K
The absorbance of UV and visible (UV–visible) radiations is measured using a UV–visible spectrophotometer. Deuterium lamps, which emit UV radiation, and tungsten lamps, which produce radiation in the visible region, are used as light sources in UV–visible spectrophotometers. A monochromator or prism is used for diffraction grating, i.e., to split the incoming radiation into different wavelengths. A system of slits is used to focus the desired wavelength on the sample cell.
3.8K
01:29IR and UV–Vis Spectroscopy of Aldehydes and Ketones
7.5K
Infrared spectroscopy, also known as vibrational spectroscopy, is mainly used to determine the types of bonds and functional groups in molecules. In aldehydes and ketones, the carbonyl (C=O) bond shows an absorption around 1710 cm-1. The C=O bond vibration of an aldehyde occurs at lower frequencies than that of a ketone. In addition to the C=O absorption in an aldehyde, the aldehydic C–H bond also gives two peaks in the 2700–2800 cm-1 range. This absorption, coupled with the...
7.5K
01:28IR and UV–Vis Spectroscopy of Carboxylic Acids
5.9K
In IR spectroscopy of carboxylic acids, the C=O bond shows a characteristic band between 1710 and 1760 cm⁻¹, and the O–H bond exhibits a broad band between 2500 and 3300 cm⁻¹.
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency,...
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency,...
5.9K
01:32UV–Vis Spectroscopy of Conjugated Systems
8.5K
Organic compounds with conjugated double bonds show strong absorption features in the UV–visible region of the electromagnetic spectrum attributed to π → π* electronic excitations. Generally, a UV–vis absorption spectrum is recorded as a plot of absorbance vs wavelength. The wavelength of maximum absorbance, which manifests as a peak in the absorption spectrum, is denoted as λmax.
One of the factors influencing λmax is the extent of conjugation in...
One of the factors influencing λmax is the extent of conjugation in...
8.5K
02:22Structures of Solids
18.6K
Solids in which the atoms, ions, or molecules are arranged in a definite repeating pattern are known as crystalline solids. Metals and ionic compounds typically form ordered, crystalline solids. A crystalline solid has a precise melting temperature because each atom or molecule of the same type is held in place with the same forces or energy. Amorphous solids or non-crystalline solids (or, sometimes, glasses) which lack an ordered internal structure and are randomly arranged. Substances that...
18.6K