Patent ID: 6569772
Filing Date: 2003-05-27
Classification: G03F

Abstract:
A method for producing an alternating phase mask, which comprises:providing a carrier having a surface with a mask layer configured thereon; applying a first irradiation-sensitive layer on the mask layer; irradiating the first irradiation-sensitive layer; developing the first irradiation-sensitive layer and partly removing the first irradiation-sensitive layer to form a first exposure structure; using the first exposure structure as an etching mask while etching the mask layer to remove the mask layer at locations where the first irradiation-sensitive layer was removed; after etching the mask layer, removing the first exposure structure; applying a second irradiation-sensitive layer to the mask layer and the carrier; determining a first exposure dose and a second exposure dose; at locations at which the first mask layer has been removed, irradiating the second irradiation-sensitive layer with the first exposure dose and elsewhere with the second exposure dose; developing the second irradiation-sensitive layer to form a second exposure structure that has a first exposure structure thickness at locations that were exposed with the first exposure dose and that has a second exposure structure thickness, different from the first exposure structure thickness, at locations that were exposed with the second exposure dose; and etching the carrier at locations that are not covered by the second exposure structure and etching the second exposure structure with essentially an equal etching selectivity such that the carrier is etched down to a first etching depth in a region of the first exposure structure thickness and down to a second, smaller etching depth in a region of the second exposure structure thickness.