3D metrology system with internal calibration

3D metrology systems are used to examine and qualify micro-and nano-manufacturing techniques and further for reverse engineering of micro-and nanostructures. For this purpose the generation of capable and reliable 3D-coordinates in large numbers is essential. Combining classical triangulation with a new technique of calibrating measurement labels results in high rates of reliable 3D metrology data. The triangulation setup consists of a stereomicroscope mounted on a 5-axis-gantry to generate all necessary points of view. Measurement labels are projected through one stereomicroscope-port and their positions are localized through the second port. Providing the calibration rule is determined, the measurement system assigns each localized position to an absolute coordinate. For registration purposes measurement labels are projected on a semitransparent mirror. Localizing measurement labels simultaneously with an observation and a calibration camera in connection with the working distance, defines the calibration rule. By modifying the working distance between calibration camera and stereomicroscope, the measurement volume is scanned. The grid of the calibration camera chip acts as a measurement standard for the measurement labels. This approach features the spatial registration of a huge amount of measurement labels covering the measurement volume in short time without building up the optical model of the imaging.