Dynamic metrology schemes and sampling schemes for advanced process control in semiconductor processing

Abstract

Systems, methods and mediums are provided for dynamic adjustment of sampling plans in connection with a wafer (or other device) to be measured. A sampling plan provides information on specific measure points within a die, a die being the section on the wafer that will eventually become a single chip after processing. There are specified points within the die that are candidates for measuring. The stored die map information may be retrieved and translated to determine the available points for measurement on the wafer. The invention adjusts the frequency and/or spatial resolution of measurements when one or more events occur that are likely to indicate an internal or external change affecting the manufacturing process or results. The increase in measurements and possible corresponding decrease in processing occur on an as-needed basis. The dynamic metrology plan adjusts the spatial resolution of sampling within-wafer by adding, subtracting or replacing candidate points from the sampling plan, in response to certain events which suggest that additional or different measurements of the wafer may be desirable. Where there are provided a number of candidate points in the die map in the area to which points are to be added, subtracted, or replaced, the system can select among the points. Further, the invention may be used in connection with adjusting the frequency of wafer-to-wafer measurements.