Crosslinkable photoresist for extreme ultraviolet lithography

A method of forming a semiconductor device, comprising:

• depositing a photoresist layer over a material layer on a substrate, wherein the photoresist layer comprises a polymer, a crosslinker and a photoacid generator;
• exposing the photoresist layer to radiation, thereby forming a crosslinked polymer in portions of the photoresist layer exposed to the radiation;
• developing the photoresist layer to form a patterned photoresist layer;
• and
• etching the material layer using the patterned photoresist layer as an etch mask,
• wherein the polymer has the following structure (I):
• wherein:
• L1 and L2 are, at each occurrence, independently a direct bond or a carbonyloxy or halogenated alkylene linker, provided that at least one of L1 and L2 is a halogenated alkylene linker;
• L3 is, at each occurrence, a direct bond;
• Ar1 is, at each occurrence, independently halogenated or non-halogenated arylene or halogenated or non-halogenated heteroarylene;
• Q is, at occurrence, independently an acid labile group;
• X1 and X2 are, at each occurrence, independently a reactive group, or protected form thereof, capable of forming a covalent bond with the crosslinker;
• R1, R2 and R3 are, at each occurrence, independently H, alkyl or alkoxy;
• and
• 0<x/(x+y+z)<1, 0<y/(x+y+z)<1 and 0<z/(x+y+z)<1.

A method of forming a semiconductor device, comprising:

• depositing a material layer over a substrate;
• applying a photoresist composition comprising a polymer, a crosslinker and a photoacid generator over the material layer to form a photoresist layer;
• exposing the photoresist layer to an extreme ultraviolet (EUV) radiation to generate a photoacid, which catalyzes the reaction between the polymer and the crosslinker to form a crosslinked polymer in exposed regions of the photoresist layer;
• baking the photoresist layer;
• removing exposed or unexposed regions of the photoresist layer to form a patterned photoresist layer;
• and
• etching the material layer using the patterned photoresist layer as an etch mask,
• wherein the polymer has the following structure (Ia):
• wherein:
• R1, R2 and R3 are, at each occurrence, independently H or alkyl;
• Rf1 and Rf2 are, at each occurrence, independently fluoroalkylene;
• Z1 is, at each occurrence, independently F or fluoroalkyl;
• Q is, at each occurrence, independently an alkyl group, a cycloalkyl group, a hydroxyalkyl group, an alkoxy group, an alkoxyalkyl group, an adamantyl group, a cedryl group, a norbornyl group, or a tricyclodecanyl group;
• X1 and X2 are, at each occurrence, independently hydroxyl, epoxy, melamine, alkene, or alkyne;
• a1 is, at each occurrence, an integer from 0 to 4;
• and
• 0<x/(x+y+z)<1, 0≤y/(x+y+z)<1 and 0<z/(x+y+z)<1.