Abstract: Measurement data is obtained for calibration fields that have been exposed by a lithographic apparatus using different field layouts and exposure sequences. The measurement data is classified in subsets by scan direction, step direction, field size and other variables. The measurement data is indexed by a time value that varies through each exposure sequence. Time values within different exposure sequences can be related using a normalized time value based on the beginning and end of each exposure sequence. An inter-field performance model is calculated for each subset. An intra-field component of a performance model is calculated with time as a third dimension. The time-indexed performance model is used to determine intra-field corrections for a variety of product exposures having product layouts and product exposure sequences different to the calibration fields, based on time and other a variables of the product layout and product exposure sequence.

Abstract: Measurement data is obtained for calibration fields that have been exposed by a lithographic apparatus using different field layouts and exposure sequences. The measurement data is classified in subsets by scan direction, step direction, field size and other variables. The measurement data is indexed by a time value that varies through each exposure sequence. Time values within different exposure sequences can be related using a normalized time value based on the beginning and end of each exposure sequence. An inter-field performance model is calculated for each subset. An intra-field component of a performance model is calculated with time as a third dimension. The time-indexed performance model is used to determine intra-field corrections for a variety of product exposures having product layouts and product exposure sequences different to the calibration fields, based on time and other a variables of the product layout and product exposure sequence.

Abstract: A method of calibrating a substrate positioning system of a lithographic apparatus, the method including: exposing a pattern with the lithographic apparatus on an exposed layer on the surface of a substrate having a reference layer, wherein the pattern corresponds to a movement of the substrate by the substrate positioning system; measuring overlay data between the exposed layer and the reference layer on a plurality of positions on the substrate; transforming the overlay data from a spatial domain to a frequency domain by a discrete cosine transformation; modifying the overlay data in the frequency domain by selecting a subset of the overlay data; transforming the modified overlay data from the frequency domain back to the spatial domain by an inverse discrete cosine transformation; calibrating the substrate positioning system by using the modified overlay data in the spatial domain.

Abstract: A method of calibrating a substrate positioning system of a lithographic apparatus, the method including: exposing a pattern with the lithographic apparatus on an exposed layer on the surface of a substrate having a reference layer, wherein the pattern corresponds to a movement of the substrate by the substrate positioning system; measuring overlay data between the exposed layer and the reference layer on a plurality of positions on the substrate; transforming the overlay data from a spatial domain to a frequency domain by a discrete cosine transformation; modifying the overlay data in the frequency domain by selecting a subset of the overlay data; transforming the modified overlay data from the frequency domain back to the spatial domain by an inverse discrete cosine transformation; calibrating the substrate positioning system by using the modified overlay data in the spatial domain.

Abstract: A SIMD parallel processor is described comprising an array comprising processing elements, associated data storage components and access means configured to enable access to at least one of the data storage components associated with at least one of the processing elements; a control processor; memory control means configured to enable addressing of at least one of the access means for the control processor; and connecting means configured to connect the memory control means to the access means.

Abstract: A SIMD parallel processor is described comprising an array comprising processing elements, associated data storage components and access means configured to enable access to at least one of the data storage components associated with at least one of the processing elements; a control processor; memory control means configured to enable addressing of at least one of the access means for the control processor; and connecting means configured to connect the memory control means to the access means.

Abstract: A controllable light source (102) is controlled to emit modulated light, preferably using a uniquely recognizable modulation pattern. A plurality of camera units (10) captures images that contain the light source. Clock time values at a time corresponding to capture of the image are captured from respective clock circuits (120) associated with the camera units (10) that capture the images. The modulated light is detected in the captured images. Relative calibration of the clock circuits (120) with respect to each other is performed using the associated clock time values of the images wherein the modulated light is detected.