Patent ID: 6756168
Filing Date: 2004-06-29
Classification: G03F

Abstract:
A method for determining an exposure time of a wafer photolithography process, which is applied to a wafer photolithography system, said system including a production line and an inspection line, said production line proceeding in turn with said photolithography processes upon a plurality of batch production wafers ( . . . L(Nâˆ’4), L(Nâˆ’3), L(Nâˆ’2), L(Nâˆ’1), L(N), . . . where N denotes a batch number), said inspection line sampling in turn said batch production wafers after completion of said photolithography processes from said production line to fabricate corresponding batch test wafers ( . . . T(Nâˆ’4), T(Nâˆ’3), T(Nâˆ’2), T(Nâˆ’1), T(N), . . . ), each of said batch test wafers corresponding to one said exposure time for producing a corresponding batch production wafer, said batch test wafer generating a respective test value for comparison with a qualified examination value, said method for determining said exposure time of said L(N) batch production wafer comprising:recalling in a time sequence at least three batches of said batch test wafers prior to said L(N) batch production wafer and obtaining corresponding test values for said at least three batches of said batch test wafers; calculating a mean value of said test values corresponding to said at least three batches of said batch test wafers with a predetermined mathematical model; comparing said mean value with said qualified examination value and determining a margin value between said mean value and said qualified examination value to adjust and generate an appropriate process exposure time; and employing said process exposure time as said exposure time of said L(N) batch production wafer.