Substrate, a Method of Measuring a Property, an Inspection Apparatus and a Lithographic Apparatus

摘要

A second set of superimposed gratings are superposed over a first set of superimposed gratings. The second set of gratings have a different periodicity from the first set of gratings or a different orientation. Consequently the first order diffraction pattern from the second set of superimposed gratings can be distinguished from the first order diffraction pattern from the first set of superimposed gratings.

主权项

1. A substrate comprising:
a first plurality of superimposed patterns and a second plurality of superimposed patterns, said second plurality of patterns being in turn superimposed on said first plurality of patterns, wherein said first plurality of patterns are periodic patterns, said patterns having a period of d, said second plurality of patterns also being periodic patterns and having a period which is different to d such that within an image of respective diffraction patterns produced by radiation reflected by each of the first plurality of superimposed patterns and the second plurality of superimposed patterns, the diffraction patterns of at least one order corresponding to each of the first and second pluralities of superimposed patterns are spatially distinguishable from each other within said image.