Patent ID: 6866987

Claim:
A process to form a patterned mask, including a first isolated feature, comprising: providing a reticle bearing a pattern that includes said first feature; adding to said pattern one or more second features located close to said first features, whereby said first feature becomes part of a densely populated section of said pattern; providing a substrate and coating it with a first layer of a material that is highly soluble in an etchant and that is patternable through development following selective exposure to radiation; coating said first layer with a second layer of a material that is resistant to etching and that is patternable through development, following selective exposure to radiation, thereby forming a bilayer; exposing said bilayer to a radiated image of said reticle pattern and then developing said bilayer, whereby said pattern forms on the substrate; and using said etchant, removing part of said first layer thereby undercutting the second layer to a degree sufficient to remove said second features through lift-off while leaving said first feature in place.