Patent ID: 8291351

Claim:
A computer implemented method of storing pattern information in a database comprising: using at least one processor that is configured or programmed for performing a process, the process comprising: receiving a request to check whether information of a new pattern needs to be stored in a database, wherein the new pattern is represented by a pattern signature derived according to lithography effects to the new pattern; comparing the pattern signature representing the new pattern with pattern signatures representing the patterns of which the information is already stored in the database; storing the information of the new pattern in the database if none of the pattern signatures representing the patterns of which the information is already stored in the database matches the pattern signature representing the new pattern; associating the pattern signature representing the new pattern with the information of the new pattern stored in the database; and flagging the new pattern if one of the pattern signatures representing the patterns of which the information is already stored in the database matches the pattern signature representing the new pattern.