FX40 with monitor

Accurion RSE

Referenced Spectroscopic Ellipsometry Fast Inspection of Thin Films and Surfaces

The Referenced Spectroscopic Ellipsometer (RSE) is an ellipsometer based reflectometer, designed for high speed thickness mapping in, e.g., quality control. It allows to accurately measure thicknesses from 0.1 nm - 10 µm. With 200 complete spectra recorded per second, a 100 mm x 100 mm area can be investigated in only 12 minutes while acquiring 67000 spectra.

Key Features

  • Modular setup: Easy upgrades between different configurations from BAM, single wave-, multiwave- to full spectroscopic ellipsometer
  • Spectroscopic imaging ellipsometry from 190/250/360 nm to 1000/1700/2700 nm
  • Highest lateral ellipsometric resolution of 1 µm, allowing to determine thickness and refractive index on microstructures as small as 1 µm
  • Ellipsometric enhanced contrast images for a live visualization of the sample
  • First identify, then measure: Intuitive selection of measurement region by drawing region in live view
  • Parallel measurement of multiple regions within the selected field of view
  • Patented knife-edge illumination for the non-destructive suppression of disturbing backside-reflections
  • Enlarge your measurement possibilities by using additional accessories, e.g. cells, temperature control or liquid handling
  • Quality Control: Also available as OEM version for QC in product lines

Referenced Spectroscopic Ellipsometry in a Nutshell

Technology

What are the Benefits of Referenced Spectroscopic Ellipsometry Compared to Conventional Ellipsometry or Reflectometry?

The referenced spectroscopic ellipsometer combines the high sensitivity of an ellipsometer with the measurement speed of a reflectometer, and even exceeds it. In comparison to a laser ellipsometer, it includes the spectroscopic information between 450 and 900 nm. This is important in the event that more than one parameter of the processed layer is variable, for instance thickness and optical density. Basically, referenced methods are more sensitive than absolute methods. Therefore, the RSE method is superior to conventional ellipsometry when very thin layers are in focus. The advantage of increased sensitivity to thin films is even more evident when compared to reflectometry.

Technology

What is Ellipsometry?

Ellipsometry is a very sensitive optical method which has been used for about a hundred years to derive information about surfaces. It makes use of the fact that the polarization state of light may change when the light beam is reflected from a surface. If the surface is covered by a thin film (or a stack of films), the entire optical system of film and substrate influences the change in polarization. Therefore, it is possible to deduce information about the film properties, especially the film thickness.

Technology

How Does Referenced Spectroscopic Ellipsometry Work?

The RSE is a special type of ellipsometer, which compares the sample to a reference. In this way, the ellipsometric difference between sample and reference can be measured. Due to the orientation of the reference, none of the optical components needs to be moved or modulated during measurement, and the full high resolution spectrum can be obtained in a single-shot measurement. Thus, 200 spectra per second are acquired. The synchronized x-y stage enables acquisition of large field film thickness maps within a few minutes. As the reference compensated system is an ellipsometer, the measured data needs to be fitted to an optical model to obtain optical parameters like the complex refractive index and/or the film-thickness. To deal with the high data-rate, a look-up-table-fitting was implemented. Prior to the measurement, a look-up-table is calculated. The measured data can then be fitted in real-time and in high resolution.

Accurion RSE: Fast Wafer Inspection

Applications

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2D-Materials

Imaging spectroscopic ellipsometry characterizes graphene and other 2D materials, analyzing CVD grown, exfoliated, and epitaxially grown flakes with the ep4 ellipsometer.

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Curved Surfaces

Ellipsometry measures thin films and AR coatings on flat and curved surfaces. The ep4 ellipsometer addresses AR coating issues on micro-lens arrays.

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Transparent Substrate

Thin films on transparent substrates are key for flexible displays. Knife edge illumination suppresses reflections, allowing non-destructive examination.

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Surface Engineering

Silanization bonds mineral/inorganic and organic components in paints and adhesives. Imaging ellipsometry examines bond formation in structured arrays without fluorescence markers.

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Air-Water Interface

The air/water interface is crucial in biophysics and industry. Brewster angle microscopy (BAM) visualizes Langmuir-Blodgett monolayers and biological materials, investigating molecules, proteins, drugs, DNA, and nanoparticles.

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Anisotropic Films

Anisotropic micro crystals are promising for electronics. Imaging Mueller Matrix Ellipsometry (IMME) measures refractive indices and optical axis orientation in anisotropic thin-film samples like Black Phosphorous.

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Bio Interfaces

Imaging Ellipsometry (IE) provides high sensitivity for mono- and sub-monolayer thickness. It offers micromaps of ellipsometric angles and a contrast mode for thickness changes. Accessories like cells and QCM-D enhance its biological application capabilities.

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MEMS

Spectroscopic ellipsometry measures MEMS structures as small as 1µm, with 0.1nm film thickness resolution. A single measurement provides thickness, refractive index, composition, and contaminations. ECM mode allows fast quality control and curved surface measurements.

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Photonics

Spectroscopic ellipsometry measures optical fibers and waveguides with 1µm lateral resolution and 0.1nm thickness resolution. It covers 190nm to 1700nm, extendable to 2700nm, providing optical data and fast quality control.

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Displays

Spectroscopic measurements on micron-scale regions use the ROI concept for multiple measurements in one run. The UV range down to 190nm characterizes display materials. A single measurement provides thickness, dispersions, and compositions, with RCE6 mode allowing sub-20-second tact times.

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Battery Materials

Operando Imaging Ellipsometry monitors battery electrode materials during charging and discharging, measuring microscopic maps of Delta and Psi. It provides data from various regions, with post-processing analysis including profiles, sub-region, and histogram analysis.