MINAFAB Characterization equipments

White Light Interferometer

Technical characteristics:

Caracteristics: manual translation stage 100x100 mm range, 20μm resolution; optical head vertical range 150 mm; nanometric objective translation unit; capacitive sensor closed loop control, 500 μm range; white light and Monochromatic light source; automatic switching, software control; antivibration feet; field of view 126 x 96 μm up to 2.5 x 1.9 mm depending on objective (without zoom); white light profilometry, 3 nm rms z resolution; monochromatic light profilometry, 0.1 nm rms z resolution; automatic step height and roughness measurement; semi-automatic focus detection; results exploitation (heights, roughness, dimensions, field stitching, filtering, 3D view, bump size, height, roughness measurements); motorized x0.35 to 1.6 zoom; out of plane measurements (by stroboscopic interferometry within range 100Hz - 2MHz and by time averaged operation without frequency limitations); synthetized function generator: 2 channels controlled by software (one channel for stroboscopic illumination, the other one for MEMS AC voltage supply); high voltage module (amplitude up to 200V; offset up to 200V; 1% resolution; sinusoidal and square signal; power 20W; current output max 100 mA); multi-reflectivity (5%,25%,50%,85%) objectives (x2.5, x5, x20); motorised XY stage; active vibration isolation stage.


The white light interferometer perform optical, non-contact profiling of rough surfaces, that uses interferometric techniques as well as digital signal processing algorithms to produce fast, accurate, repeatable two and three-dimensional surface profile measurements. The method of determining surface height is based on white light as the source in an interferometer, and measurements of the fringe modulation degree, or coherence, instead of the phase of interference fringes. The white light interferometric profilometer uses the measurement of surface height through vertical scanning of the reference arm of the interferometer, and calculate the relative modulation of the intensity signal as a function of vertical position. The equipment present sub-nanometer vertical resolution (down to 0.1 nm) at all magnifications, non-contact measurements allowing accurate and repeatable results, all axes motorization enabling automatic stitching of multiples fields of view, sub-nanometric roughness measurements, reflectivity 1% to 100%, ability to measure transparent films and require no sample preparation.



  • Optical profilometer allow to measure the surface topography of very diverse materials (such as metals, plastics, semiconductors, biological materials etc);
  • Ca be used for residual stress measurement for different thin film deposition layers;
  • Conceived not only for statistical surface roughness measurements but also for high precision measurement of mechanical or chemical micromachining;
  • Useful for thickness measurements of transparent layers (pastics, glasses or varnish) with known refraction indices;
  • Can be used for MEMS dinamic measurements



Thin film thickness measurement (Au; ~15nm) – used for thin film
deposition system calibration

Optoelectronics –
SU8 guide manufactured on silicon substrate

RF filter
on thin dielectric membrane (1.5µm, SiO2/Si3N4/ SiO2) –
used for topography measurement

Analysis of the stress influence over the circuit topography



  • MIMFOMEMS- Advanced circuits for microwave, millimeter wave and photonics based on MEMS technologies;
  • MEMS-4-MMIC- Enabling MEMS-MMIC technology for cost-effective multifunctional RF system integration;
  • GIGASABAR- SAW and FBAR type resonators dedicated to applications in communications for 2-6 GHz, based on micro&nanomachining of wide band semiconductors (GaN and AlN);

Application scientist: dr. phys. Alina Cismaru, alina.cismaru@imt.ro


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Last update: March 5 2012