Patent ID: 6897010
Filing Date: 2005-05-24
Classification: G03F,H01L

Abstract:
1. A method of recording mutually different identifiers on multiple plate members, each said identifier including a group of character strings having character strings A and B, the character string A including a number z 1 of characters, the character string B including a number z 2 of characters, where z 1 is a natural number greater than 1 and z 2 is a natural number, the method comprising the steps of: (a) preparing a photomask of a first type having an opaque pattern that defines the character string A, where, if there are S possible symbols for each character in the character string A, then the number of photomasks needed to form each possible character string A is S (b) preparing at least one photomask of a second type having an opaque pattern that defines one of the characters of the character string B, where, if there are T possible symbols for each character in the character B, then the number of photomasks needed to form each possible character string B is T; (c) forming a photoresist layer on the surface of one of the plate members; (d) forming a latent image of the character string A in the photoresist layer in a single radiation exposure step by using the photomask of the first type; and (e) forming a latent image of each of the characters of the character string B in the photoresist layer in z the combination of character strings A and B is used to uniquely identify each of the multiple plate members.