Patent ID: 7364840
Filing Date: 2008-04-29
Classification: G03F

Abstract:
1. A method to form an etch mask, comprising providing a substrate and depositing thereon an under-layer of a lithographic material that, after development, is dimensionally unaffected by exposure to ultraviolet radiation; depositing, on said under-layer, a layer of photoresist having a development rate that is slower than that of said under-layer; exposing both of said layers to radiation whereby a latent image is formed; developing both layers whereby said under-layer has a smaller developed image than does said photoresist layer and whereby said layer of photoresist overhangs said under-layer, extending outwards therefrom as a horizontal cantilever; and then exposing both layers to ultraviolet radiation alone, with no heat being applied, whereby said photoresist layer shrinks uniformly in all directions, including normal to said substrate, thereby continuing to extend outwards therefrom as a horizontal cantilever, while said under-layer remains dimensionally unchanged, thereby forming said etch mask.