Monitoring system and method for verifying measurements in patterned structures

A system for process control of manufacturing semiconductors devices, the system controlling measurements of parameters of patterned structures, the system comprising:

• (a) an optical measurement unit configured and operable to apply one or more optical measurements to a patterned structure of a semiconductor wafer and generate measured data indicative of the one or more optical measurements in the at least one patterned structure,
• the one or more optical measurements being measurement of one or more parameters of the patterned structure including at least one of layer thickness, optical critical dimensions, width of features of the patterned structure, height profile of features of the patterned structure, spacing between features of the pattern structure, and optical properties of materials of the patterned structure,
• the one or more optical measurements including
• applying incident radiation to the structure and
• detecting one or more optical response signals of the structure to the incident radiation, the measured data indicative of the one or more optical measurements including raw data comprising at least one signature corresponding to an optical response of the structure to the incident radiation;
• and
• (b) a data verification system comprising a computer system configured for data communication with the optical measurement unit and comprising a data input utility configured to receive the raw data;
• a non-transitory computer readable memory utility storing at least one fitting model;
• and
• a data processor utility, the data processor utility comprising:
• a fitting utility configured and operable to apply a fitting procedure to the measured data using the at least one fitting model;
• a verification module comprising:
• two or more error indicator utilities configured and operable to apply to the raw data and to additional data two or more different verification modes selected based on analysis of the raw data and the additional data, the additional data including at least one of:
• measurement health data, data corresponding to a desired degree of fit with the predetermined fitting model, and a one or more structure parameters calculated from a fitting procedure, such that each error indicator utility is operable to apply one or two of the two or more verification modes, and, upon determining one or more measurement problems of a different type, generate one or more corresponding error indicators indicative of a potentially erroneous measurement;
• and
• a Verification Figure of Merit utility configured and operable to
• combine the error indicators of the two or more error indicator utilities based on user defined weights assigned to the error indicators, and
• apply threshold based analysis to the error indicators using a predetermined control limit to classify the raw data as corresponding to acceptable or unacceptable measurement providing, respectively, acceptable or unacceptable measurement result, and, upon classifying the raw data as corresponding to acceptable measurement,
• apply a fitting procedure with a predetermined fitting model to the raw data corresponding to the acceptable measurement result to determine a measurement result for one or more parameters of the patterned structure, and
• determine
• whether the raw data corresponding to the unacceptable measurement are to be disregarded from further processing by the fitting procedure to determine the measurement result for one or more parameters of the patterned structure, or
• whether one or more parameters of the fitting model are to be modified.