Patent ID: 7342643
Filing Date: 2008-03-11
Classification: G03F

Abstract:
1. A method of aligning a wafer with a reticle in photolithographic exposure equipment, comprising: loading a wafer onto an exposure apparatus in which the reticle is supported; aligning the wafer with the reticle in the exposure apparatus, measuring a state of alignment between the wafer and the reticle, and producing alignment data representative of the measured state of alignment between the wafer and the reticle; using the alignment data to search a database and select from the database an alignment data type under which the alignment data falls; searching the database for overlay data associated with the selected alignment data type, the overlay data being characteristic of the overlaying of images on region of a wafer which has been exposed sequentially in the exposure apparatus; using the overlay data to obtain a correction value suited to the alignment data type; applying the correction value to the alignment data to produce updated alignment data; correcting the alignment of the wafer with the reticle using the updated alignment data; and subsequently exposing the aligned wafer to light directed through the reticle.