Abstract: A method of forming a pattern in at least one device layer in or on a substrate comprises: coating the device layer with a first photoresist layer; exposing the first photoresist using a first mask; developing the first photoresist layer to form a first pattern on the substrate; coating the substrate with a protection layer; treating the protection layer to cause a change therein where it is in contact with the first photoresist, to render the changed protection layer substantially immune to a subsequent exposure and/or developing step; coating the substrate with a second photoresist layer; exposing the second photoresist layer using a second mask; and developing the second photoresist layer to form a second pattern on the substrate without significantly affecting the first pattern in the first photoresist layer, wherein the first and second patterns together define interspersed features having a spatial frequency greater than that of the features defined in each of the first and second patterns separately.

Abstract: A method of forming a pattern in at least one device layer in or on a substrate comprises: coating the device layer with a first photoresist layer; exposing the first photoresist using a first mask; developing the first photoresist layer to form a first pattern on the substrate; coating the substrate with a protection layer; treating the protection layer to cause a change therein where it is in contact with the first photoresist, to render the changed protection layer substantially immune to a subsequent exposure and/or developing step; coating the substrate with a second photoresist layer; exposing the second photoresist layer using a second mask; and developing the second photoresist layer to form a second pattern on the substrate without significantly affecting the first pattern in the first photoresist layer, wherein the first and second patterns together define interspersed features having a spartial frequency greater than that of the features defined in each of the first and second patterns separately.

Abstract: The invention relates to a method of photolithography comprising the steps of: providing a substrate and forming a layer of a photoresist (100) on the substrate, performing a first exposure (120) in which a predetermined part of the layer of photoresist is irradiated through a mask having a pattern for forming a latent image of said pattern in the layer of the photoresist, performing a pretreatment (130) on the layer of the photoresist to remove a predetermined part of the latent image before performing the fixation (140). The method provides an improved process window. The invention further relates to a photoresist for use within the method of the invention.