| 摘要 |
A method of determining a coordinate value of a position with respect to patterns of a substrate using a sensing device is provided. Each pattern represents respective sequences. Each sequence consists of a repeating codeword of a cyclic position code. The cyclic position code has length n<SUB>1 </SUB>and minimum distance d<SUB>min</SUB><SUB><SUB2>1</SUB2></SUB>. The method includes sensing, using the sensing device, at least pan of h<SUB>1 </SUB>of the corresponding patterns, where h<SUB>1</SUB>>=2, obtaining, from each of h<SUB>1 </SUB>sensed patterns, a respective subsequence of length w<SUB>1 </SUB>symbols, where w<SUB>1</SUB>>=n<SUB>1</SUB>-d<SUB>min</SUB><SUB><SUB2>1</SUB2></SUB>+1, mapping each of the subsequences to a respective mapped codeword of the cyclic position code, determining an offset indicative of the position, in the corresponding, sequence, between each mapped codeword and the codeword, deriving, for each of h<SUB>1</SUB>-1 pairs of the first sequences, a difference between the corresponding pair of offsets, and thereby deriving a respective difference and as such the coordinate value. |
