Method and device for optically monitoring fabrication processes of finely structured surfaces in a semiconductor production

A device for monitoring fabrication processes of structured surfaces in a semiconductor production, comprising:

• a reference signature apparatus for providing reference signatures of structured surfaces, said reference signature apparatus being configured for performing a measurement of reference signatures by measuring an intensity distribution of images varying at least a wavelength and a polarization of an electromagnetic radiation, the images being selected from the group consisting of diffraction images and scattered light images of a plurality of individual structures of a surface of production prototypes having a specified quality;
• an apparatus for providing at least one of a neural network and a fuzzy logic having a learning capability by adjusting a weighting of the at least one of the neural network and the fuzzy logic as a function of the reference signatures;
• a measuring apparatus operatively connected to said reference signature apparatus, said measuring apparatus measuring at least one signature associated with a test specimen surface to be monitored by simultaneously registering a plurality of individual structures of the test specimen surface to be monitored by using an intensity distribution of images varying at least a wavelength and a polarization of an electromagnetic radiation, the images being selected from the group consisting of diffraction images and scattered light images for providing a measured signature, measurements for both the reference signatures and the at least one signature of the test specimen surface to be monitored being performed one at a time;
• a rotation apparatus for varying the polarization of the electromagnetic radiation by rotating an electromagnetic radiation source;
• a comparison module operatively connected to said measuring apparatus, said comparison module comparing the measured signature with the reference signatures and providing comparison results by using at least one of the fuzzy logic and the neural network to evaluate similarity between the reference signatures and the measured signature;
• a classification module operatively connected to said comparison module;
• and
• a high-resolution measuring device for measuring individual structures of the test specimen surface for providing absolute quantities of the individual structures on the surface with high resolution and for providing a further reference signature, the weighting of the at least one of the neural-network and the fuzzy logic being adjusted as a function of the further reference signature;
• said classification module classifying parameters of the test specimen surface based on the comparison results, if a similarity between the reference signatures and measured signature has been found in the comparison step, otherwise classifying parameters of the test specimen surface based on the measurement of the individual structures.