Patent attributes
The invention relates to a method of inspecting a mask comprising the steps: patterning a semiconductor material with a reference mask, patterning the semiconductor material with the mask as the inspection item, inspecting both patterns on the semiconductor material by means of an apparatus suitable for inspecting the semiconductor material, and comparing the pattern generated by the inspection item mask to the pattern generated by the reference mask to detect deviations in the inspection item mask from the reference mask. The invention is particularly suitable for reticule inspection. When a semiconductor wafer is multiply patterned by the reference mask and the inspection item mask alternatingly side-by-side, deviations in the reticules are evident as recurrent discrepancies between the patterns on the wafer.
