Patent attributes
A method for being used in a lithography process is provided. The method includes receiving a first mask, a second mask and a substrate with a set of baseline registration marks. A first set of registration marks is formed on the substrate using the first mask and a first exposure tool, and a first set of overlay errors is determined. The first set of registration marks is removed and a second set of registration marks is formed on the substrate using the second mask and a second exposure tool. A second set of overlay errors is determined. A set of tool-induced overlay errors is generated from the first and second sets of overlay errors and used in fabricating a third mask. The third mask can then be used in the lithography process to accommodate the overlay errors caused by different exposure tools, different masks, and different mask writers.
