Patent ID: 6193899
Filing Date: 2001-02-27
Classification: G03F,H05K

Abstract:
A method for aligning a first layer of material having a target and a second layer of material having a target, the target in the first layer of material and the target in the second layer of material comprising a set of targets, at least a portion of the second layer of material positioned parallel to the first layer of material, the method comprising the steps of:(a) directing electromagnetic radiation toward the target in the first layer of material;(b) detecting the intensity of the electromagnetic radiation traveling from the target in the first layer of material and through the target in the second layer of material, wherein the intensity of the electromagnetic radiation detected through the set of targets provides information regarding alignment of the first layer of material and the second layer of material along both X and Y directions;(c) determining a relative position of the first layer and the second layer with respect to each other by examining the intensity of electromagnetic radiation detected through the set of targets; and(d) in response to determining that the first layer and the second layer are not aligned properly, shifting the position of the first layer, and repeating steps (a) through (d) until the first layer and the second layer are aligned properly.