Character string comparison in data recovery device for photomask production control during semiconductor manufacture, involves comparing number of marks in character strings to obtain deviation number

摘要

The number of marks in two character strings are compared. When both are same, the characters are compared at same portions of the strings and number of deviations is obtained. When number of marks are different, comparison is repeated with the previously used character, if registered characters are not same. The number of deviations is obtained by halving the number of repeated comparisons and remaining characters. An Independent claim is also included for the data recovery device.