In addition to Nova’s specialty in spectral measurements, it also invests in assisting channels that support the main metrology module. As requirement for accuracy and speed become tougher with advancing technology nodes, the complexity of these channels increases. This includes advanced image processing algorithms, sophisticated navigational channels, and robust pattern recognition capabilities: Nova’s advanced image processing algorithms allow for greatly improved precision in characterizing elements of the image that are to be measured. To enable measurement of a required location with micron-level positional accuracy, Nova also implements a combination of sophisticated hardware and software navigation aids together with highly advanced pattern recognition capabilities.
Advanced image processing for micron-scale characterization
The optical resolution of typical optical microscopes is limited by light diffraction to sub-micron. Nova’s advanced image processing algorithms allow for greatly improved precision in characterizing elements with known geometry, down to nanometric precision. These capabilities can be used for highly accurate positioning protocols over a small measurement site, assuring repeatable measurements.
Sophisticated in situ navigation channel
To enable measuring at the required position with high accuracy , Nova’s systems implement an in-situ navigation channel and advanced pattern recognition capabilities.
Robust pattern recognition algorithms
Nova systems utilize advanced pattern recognition algorithms to locate the system position on the wafer. Some of these algorithms utilize a geometrical concept that creates a model of the feature’s geometry. Such algorithms enable deep sub-pixel accuracy at a speed of milliseconds per image.