By Melbourne Centre for Nanofabrication
Profilometry is used to characterise the surface steps and the roughness of a material. Both contact and non-contact, or optical profilometry, are available at MCN. The stylus profilometer available at MCN uses a direct contact method to register slight changes in the surface height of a material. This is achieved by dragging a metal tip along the surface of a sample and measuring the distance traced by the stylus tip and its deflection along the vertical axis. This measurement is then converted into a cross-sectional plot and can be used to resolve steps as small as 10nm. Optical profilometry employs phase-shifting and/or vertical scanning interferometry to resolve the topology of complex 3D structures. The technique marries precision z-axis control with interference based techniques to resolve features from the angstrom to millimetre scale. The technique lends itself well to die-based measurements for ISO/QA and large area mapping. Profilometry is useful in process control steps such as measuring etch depth and lithography patterns. MCN’s two profilometers are the Ambios XP 200 and the Bruker Contour GT-I. The Bruker DektakXT-A is a fully automated, contact profilometer measures the thin film thickness of patterned features by sensing the deflection of a fine stylus that is raster scanning over features ranging in height from 1 mm down to 5 nm. It is capable of mapping step heights and displaying topological three dimensional images of substrates ranging from 150 mm diameter wafers down to small pieces. The Bruker Contour GT-I Optical Profilometer is a fully automated, desktop optical microscope which measures surface features over a range of angles. The combination of tip/tilt in the head with automated staging and objectives, as well as vibration resistant measurement techniques, make the Contour GT-I ideal for measure on demand industrial requirements.
