Patent ID: 8715910

Claim:
A method for generating on a wafer a focus exposure matrix having a plurality of focus exposure fields, each focus exposure field including a plurality of structures, the method comprising: exposing each of the focus exposure fields for generating the plurality of structures; wherein the exposing comprises: adjusting a focus offset of a beam with respect to the focus exposure field on the wafer; tilting the beam or tilting the wafer; exposing the focus exposure field on the wafer to the beam, thereby generating locations within the focus exposure field exposed with different foci; wherein, starting from a focus exposure field exposed with no focus offset and no tilting, a first number of focus exposure fields exposed with increasing focus offset and tilting, and a second number of focus exposure fields exposed with decreasing focus offset and tilting are generated; and wherein tilting comprises adjusting the beam and the focus exposure field on the wafer mutually so that an angle between the beam and the focus exposure field on the wafer is different to 90°.