Patent ID: 8230371

Claim:
A method for calibrating a critical-failure model regarding a printing failure of a critical feature in a physical layout of a print pattern of an integrated circuit on a wafer substrate, comprising: providing a print-failure criterion for the critical feature of the print pattern of the integrated circuit, the print-failure criterion being related to a geometrical parameter in a print of the critical feature, as derived from test-print-simulation data simulating the print; providing test-print-simulation data by computer representing print simulations of different test patterns, which have the critical feature of the print pattern of the integrated circuit, wherein the different test patterns differ between each other in their respective values of the geometrical parameter of the critical feature; ascertaining a predefined optical-parameter set from the test-print-simulation data at the print position of the critical feature; scanning the test-print-simulation data for the presence of print-failures according to the print-failure criterion; and classifying regions in an optical-parameter space spanned by at least one optical parameter of the optical-parameter set according to at least two print-criticality levels using the detected print failures in the test-print simulations at respective points of the optical-parameter space; wherein the predefined optical-parameter set is ascertained from the test-print-simulation data at only one sampling point of a process window, which sampling point is identical for all test patterns; at least one failure rule is provided before the classifying of the optical-parameter space, which failure rule provides trend information for points in the optical-parameter space, the trend information being indicative of a trend of the geometrical parameter in a print of the critical feature of a test pattern when moving from said sampling point in the process window to a different process-window point; and wherein classifying regions in the optical-parameter space comprises ascertaining the respective print-criticality levels from the test-print-simulation data at the sampling point and from the failure rule.