Patent ID: 9424636
Filing Date: 2016-08-23
CPC Classification: G03F,G06T

Claim Text:
1. A method for measuring positions of structures on a mask and thereby determining mask manufacturing errors comprising: determining from a plurality of measurement sites an influence of an optical proximity effect on a position measurement of structures on the mask, with a metrology tool; selecting an area on the mask from mask design data which contains a data representation of the structures to be measured by the metrology tool; carrying out an image rendering of the data representation of the structures, wherein at least one rendered image of the mask design data is obtained; moving a measuring table of the metrology tool in a plane parallel to a surface of the mask and thereby placing an area of the mask in a field of view of an imaging system of the metrology tool, wherein the area of the mask is located at a position on the mask which corresponds to a position of the area on the mask selected from mask design data; capturing at least one optical image of a pattern within the area of the mask with the imaging system of the metrology tool; and, determining a residual from an at least one rendered image of the structures according to the mask design data and an at least one optical image of the structures on the area on the mask.