The Keyence laser-scanning confocal microscope (LSCM, or laser profilometer) functions by scanning a highly convergent laser beam over the surface of the sample. The reflected light is refocused to a pinhole in front of a detector which measures the intensity of laser light passing through the pinhole. When the confocal volume (the intersection of the laser illumination volume with the acceptance of the pinhole detector) coincides with the surface, the measured intensity is high. If the confocal volume does not intersect the surface, the measured intensity is lower. The position of the objective lens relative to the surface is scanned, and the system uses the variation in measured intensity as a function of lens height — for each pixel in the image — to identify the z-position of the surface.
The Keyence VK-X260 microscope has a lateral resolution of ~100 nm, and the vertical sensitivity can be as good as 5 nm under ideal conditions. It is capable of multiple imaging modalities, including laser intensity, height, and (lower resolution) color images, and it can create composite images combining color and laser image information. A vertical height extender allows for a wide range of sample heights up to ~5″.
The microscope has a sophisticated suite of analysis software which is available for distribution to users of the facility. The software is capable of roughness analysis, profile analysis, surface comparison, area/volume determination, film thickness measurements of semi-transparent films, batch processing, and even exporting to CAD STP files.