Monomers, polymers, photoresist compositions and methods of forming photolithographic patterns

A photoresist composition, comprising:

• a polymer, comprising:
• a unit formed from a monomer of the following general formula (I):
• wherein:
• L represents a single bond or a C1 to C10 organic group;
• R1 represents hydrogen or a C1 to C3 alkyl group;
• R2 each independently represents a hydrogen atom or a C1 to C10 organic group;
• R3 each independently represents a hydrogen atom or a C1 to C10 organic group, those bonded to a common carbon atom together optionally forming a ring;
• and R4 each independently represents a C1 to C10 organic group, those bonded to a common carbon atom together optionally forming a ring;
• and
• a photoacid generator.

A coated substrate, comprising a substrate and a layer of a photoresist composition over a surface of the substrate;

• wherein the photoresist composition comprises:
• a polymer, comprising:
• a unit formed from a monomer of the following general formula (I):
• wherein:
• L represents a single bond or a C1 to C10 organic group;
• R1 represents hydrogen or a C1 to C3 alkyl group;
• R2 each independently represents a hydrogen atom or a C1 to C10 organic group;
• R3 each independently represents a hydrogen atom or a C1 to C10 organic group, those bonded to a common carbon atom together optionally forming a ring;
• and R4 each independently represents a C1 to C10 organic group, those bonded to a common carbon atom together optionally forming a ring;
• and
• a photoacid generator.

A method of forming a photolithographic pattern, comprising:

• (a) providing a substrate comprising one or more layer to be patterned over a surface of the substrate;
• (b) applying a layer of a photoresist composition of over the one or more layer to be patterned;
• (c) patternwise exposing the photoresist composition layer to actinic radiation;
• (d) heating the exposed photoresist composition layer in a post-exposure bake process;
• and
• (e) applying a developer to the photoresist composition layer to remove a portion of the photoresist layer, thereby forming a photoresist pattern;
• wherein the photoresist composition comprises:
• a polymer, comprising:
• a unit formed from a monomer of the following general formula (I):
• wherein:
• L represents a single bond or a C1 to C10 organic group;
• R1 represents hydrogen or a C1 to C3 alkyl group;
• R2 each independently represents a hydrogen atom or a C1 to C10 organic group;
• R3 each independently represents a hydrogen atom or a C1 to C10 organic group, those bonded to a common carbon atom together optionally forming a ring;
• and R4 each independently represents a C1 to C10 organic group, those bonded to a common carbon atom together optionally forming a ring;
• and
• a photoacid generator.