Patent ID: 6436595
Filing Date: 2002-08-20
Classification: G03F

Abstract:
A method for aligning a projected image of a photolithography mask pattern for a second product layer with respect to a first product layer, wherein the first product layer includes a periphery surrounding a first product area, the mask pattern for the second product layer includes a periphery surrounding a second product area, the first product area includes at least one first product feature, the second product area includes at least one second product feature, the periphery surrounding the first product area includes at least one first reference feature, and the periphery surrounding the second product area includes at least one second reference feature, the method comprising the steps of:measuring a first overlay error between the at last one first reference feature and the projected image of the at least one second reference feature; measuring a second overlay error between the at least one first product feature and the projected image of the at least one second product feature; determining at least one adjustment factor to be applied to the first overlay error between said reference features, such that said adjustment factor minimizes the second overlay error between said product features; and applying said at least one adjustnent factor to the first overlay error between said reference features.