Patent ID: 8856694
Filing Date: 2014-10-07
Classification: B29C,G03F,G05B

Abstract:
1. A computer-implemented method of controlling a lithography process by reducing a temporal drift of a performance of a lithography apparatus used for the lithography process, the method comprising: (a) defining baseline performance of the lithography apparatus, where a lithography model for the baseline performance is obtained using a first set of wafer metrology data collected from exposed patterns using the lithography process at an initial time, and wherein the lithography model is configured to simulate variations of one or more lithography process parameters in relation to one or more settings of the lithography apparatus; (b) monitoring a performance stability of the lithography apparatus by analyzing the temporal drift associated with a current performance of the lithography apparatus with respect to the baseline performance, wherein the temporal drift is determined by comparing the wafer metrology data collected at the initial time, and subsequent wafer metrology data collected from exposed patterns at a subsequent time; and (c) adjusting the one or more settings of the lithography apparatus to reduce the determined temporal drift by reducing the difference between the baseline performance and the current performance, thereby maintaining the lithography process within or substantially close to the defined baseline performance, wherein one or more steps of the method are performed by using a computer.