3D Surface Metrology

IA - Variação de Foco

Active illumination Focus Variation vertically scans either optics (with very low depth-of-field) or the sample to obtain a continuous set of images of the surface. An algorithm determines which points in each frame are in focus, and an entire image is built up using all in-focus points from all frames. It has been improved with the use of active illumination to get more reliable focus location even on optically smooth surfaces.

Confocal

The imaging technique included by the Confocal microscopes, utilizes an aperture at the confocal plane of the objective. Out-of-focus light is thus prevented from entering the imaging system and only the in-focus plane on the sample is captured. 2D profiles and 3D surface images can be captured by scanning the aperture mechanically or digitally.

Interferometria

Optical Interferometry makes use of the optical path difference between light reflected in the two arms of the interferometer (reference and sample) to yield an spatial interference pattern (interferograms) that contains information on the surface topology of the sample. Various variations of the approach can be used for particular applications.

Filmes finos

The thin film measurement technique quickly and accurately measures the thickness of optically transparent layers needing sample preparation. The profilometer captures the reflectance spectrum, which is then compared to simulated spectra to find the optimal layer thickness. It can measure transparent films from 50 nm to 1.5 μm in under a second, with evaluation spot diameters ranging from 0.5 μm to 40 μm based on objective magnification.