Spectroscopic Metrology

© Fraunhofer ILT

Spectroscopy

Microscopical measurement of the sheet resistance of an ITO- coating in the area of process parameter changes (flash lamp annealing).
© Fraunhofer IWS Dresden

Microscopical measurement of the sheet resistance of an ITO- coating in the area of process parameter changes (flash lamp annealing).

Laser spectroscopic methods make it possible to conduct chemical analyzes of materials in all aggregate states. Reflection, transmission and absorption measurements as well as special forms of emission measurement, such as fluorescence and Raman spectroscopy, can determine characteristic features and compositions of atoms and molecules.

Laser-induced breakdown spectrometry (LIBS), developed at Fraunhofer ILT, can be used to carry out multi-element analyzes, which can be supplemented by laser-induced fluorescence or Raman spectroscopy and molecular or crystal structure information. When laser ablation processes are integrated into the process, coated and contaminated materials can also be tested to determine their core composition.

For the most part, Fraunhofer ILT develops processes for those applications in which the advantages of laser spectroscopy – as fast and non-contact analyzes – can be used profitably. Metallic materials are examined directly in process lines in order to detect material mix-ups in time; mineral resources are captured inline in order to compensate for quality fluctuations through improved process management. For the recycling of materials, individual parts are classified on conveyor belts in order to divide them into mono-fractions. Material tests with measuring rates in the kHz range are used for imaging analyzes in order to represent material structures and defects quickly and with little sample preparation time.

Gas and particle measurement technology

Fraunhofer IPM focuses on the following in gas and particle measurement technology:

IR spectroscopy: For example, Fraunhofer IPM has developed a fast IR-filter spectrometer for the test stand to dynamically measure hydrocarbons in passenger-car exhaust gas. The system measures the concentration of different exhaust gas components simultaneously with a time resolution of five milliseconds and thus can analyze and optimize dynamic processes in multi-stage catalytic converter systems.

Gas measurement technology: Various methods of spectroscopy – from UV to MIR – are used in gas measurement technology. Miniaturized gas sensors, system components and sensor systems are particularly suitable for certain applications. These include, for example, application-specific semiconductor gas sensors and colorimetric gas sensors as well as radiators that can be modulated for the medium infrared.

Particle measurement technology: Different methods are used depending on a customer’s needs. Spectroscopic and microscopic methods are available in addition to scattered-light measurement methods for the rapid determination of particle size distributions – if appropriate, in combination with fluorescence measurement processes for the differentiation of particles.

Thin-film metrology technology

When complex optical layer systems are deposited, the thicknesses of the individual layers are of enormous importance. To account for this, Fraunhofer IST has developed the modular monitoring system MOCCA+® – innovative hardware and software that monitor and fully automate coating systems to produce (precise) optical systems. In this case, the transmission or reflection is measured in-situ at a wide spectral range from UV to SWIR, i.e. of wavelengths of up to approx. 2500 nm.

Laser-diode spectroscopy makes it possible to reliably detect the water vapor transmission rate (WVTR) of flexible ultra-barrier systems in the range of 10-6 grams per square meter and day. The new detection concept developed by Fraunhofer IWS, which combines a number of advantages, has been implemented as a compact laboratory device.

Moreover, hyperspectral imaging (HSI) provides spectroscopic imaging in the near infrared (NIR), visible (VIS) or ultraviolet (UV) range of the light, and allows a temporally or spatially resolved measurement of all spectral features. This way, the product or process can be analyzed both comprehensively and completely (100 percent). When the process is coupled with a microscope, the investigations extend down to the submicrometer range.

Processing and interpreting the data obtained are essential prerequisites for making measurements of high specificity. For this purpose, the Data Management Competence Center offers appropriate tools in cooperation with the Technische Universität Dresden and Dresden University Hospital. Together, the partners develop interactive assistance systems and methods for large data sets (big data). They focus on digital image data, which are used for early detection, temperature measurement, diagnosis, therapy planning, therapy support or success monitoring. Research and development range from image acquisition, image processing, modeling and visualization to user interface and application design.

For the analysis of thin-film systems both in-situ and as a means of product control, various spectroscopic methods have been developed and qualified as a system. As a key competency, Fraunhofer FEP provides systems to analyze chemical compositions:

  • Energy dispersive spectrometry of X-rays (EDS),

  • Optical glow-discharge spectrometry (GD-OES)

Hyperspectral Imaging

In addition, the Fraunhofer IWS offers hyperspectral imaging (HSI) spectroscopic imaging in the near infrared (NIR), visible range (VIS) or ultraviolet (UV) range of light and enables a time- or spatially resolved measurement of all spectral features. This allows a full and complete (100 percent) analysis of the product or process. The possibility of microscope coupling extends the investigations down to the sub-micron range.

The processing and interpretation of the data obtained is an essential prerequisite for a measurement of high specificity. To this end, for example, the Competence Center Data Management in cooperation with the TU Dresden and the University Hospital Dresden offers appropriate tools. Together, the partners develop interactive assistance systems and methods for large amounts of data (BigData). The focus is on digital image data that is used for early detection, temperature measurement, diagnosis, therapy planning, therapy support or performance control. Research and development ranges from image acquisition, image processing, modeling and visualization to user interface and application design.

 

Your contacts at the institutes are:

Contact Press / Media

Dr. Wulf Grählert

Fraunhofer Institute for Material and Beam Technology IWS
Winterbergstr. 28
01277 Dresden

Phone +49 351 83391-3406

Contact Press / Media

Dr. Michael Vergöhl

Fraunhofer Institute for Surface Engineering and Thin Films IST
Bienroder Weg 54 e
38108 Braunschweig

Phone +49 531 2155-640

Contact Press / Media

Dr. rer. nat. Cord Fricke-Begemann

Fraunhofer Institute for Laser Technology ILT
Steinbachstr. 15
52074 Aachen

Phone +49 241 8906-196

Fax +49 241 8906-121

  • Send email

Contact Press / Media

Prof. Dr. Jürgen Wöllenstein

Fraunhofer Institute for Physical Measurement Techniques IPM
Heidenhofstr. 8
79110 Freiburg

Phone +49 761 8857-134

Fax +49 761 8857-224

  • Send email

Contact Press / Media

Dr. Olaf Zywitzki

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP
Winterbergstr. 28
01277 Dresden

Phone +49 351 2586-180

Fax +49 351 2586-55180