Pattern forming method, chemical amplification resist composition and resist film

A chemical amplification resist composition, comprising:

• (A) a resin capable of increasing a polarity of the resin (A) to decrease a solubility of the resin (A) for a developer containing an organic solvent by an action of an acid;
• (B) a compound capable of generating an acid upon irradiation with an actinic ray or radiation;
• and
• (C) a solvent,
• wherein a leaving group capable of decomposing and leaving by an action of an acid is:
• (ii) a structure represented by the following formula (b), which decomposes by an action of an acid to generate one alcoholic hydroxyl group;
• or
• (iii) a structure represented by the following formula (c), which decomposes by an action of an acid to generate two or three alcoholic hydroxyl groups:
• wherein Pf2 represents a monovalent fluorine atom-containing group capable of decomposing and leaving by an action of an acid;
• Pf3 represents a z-valent fluorine atom-containing group capable of decomposing and leaving by an action of an acid;
• z represents 2 or 3;
• and
• * represents a bond to a main chain or side chain of the resin (A),
• and further wherein the leaving group capable of decomposing and leaving by an action of an acid is a group represented by the following formula (b-1), (b-3), (c-1), (c-2) or (c-3):
• wherein in formula (b-1),
• each Rx4 independently represents a hydrogen atom or a monovalent organic group, and Rx4s may combine with each other to form a ring;
• Rx5 represents a monovalent organic group, and Rx4 and Rx5 may combine with each other to form a ring;
• provided that at least one of two Rx4s and Rx5 contains a fluorine atom or a fluorine atom-containing group;
• and
• provided that when two Rx4s combine with each other to form a ring, at least either the ring or Rx5 contains a fluorine atom or a fluorine atom-containing group, or when one Rx4 and Rx5 combine with each other to form a ring, at least either the ring or another Rx4 contains a fluorine atom or a fluorine atom-containing group;
• in formula (b-3),
• each Rx6 independently represents an alkyl group, a cycloalkyl group, an aryl group, an alkenyl group or an alkynyl group, and two Rx6s combine with each other to form a ring;
• and
• at least either the ring or one remaining member out of three Rx6s contains a fluorine atom or a fluorine atom-containing group:
• wherein in formula (c-1),
• each Rx7 independently represents a hydrogen atom or a monovalent organic group, provided that at least one Rx7 contains a fluorine atom or a fluorine atom-containing group;
• and
• Rx7s may combine with each other to form a ring, and in this case, the ring contains a fluorine atom or a fluorine atom-containing group;
• in formula (c-2),
• each Rx8 independently represents a monovalent organic group, provided that at least one Rx8 contains a fluorine atom or a fluorine atom-containing group;
• and
• Rx8s may combine with each other to form a ring, and in this case, the ring contains a fluorine atom or a fluorine atom-containing group;
• in formula (c-3),
• Rx8′ represents a monovalent organic group, provided that Rx8′ contains a fluorine atom or a fluorine atom-containing group;
• and
• in formulae (b-1), (b-3) and (c-1) to (c-3), * represents a bond to a main chain or side chain of the resin (A),
• and still further wherein the resin (A) contains a repeating unit represented by any one of the following formulae (I-1) to (I-5) and (I-7) to (I-10):
• wherein each Ra independently represents a hydrogen atom, an alkyl group or a group represented by —CH2—O—Ra2, wherein Ra2 represents a hydrogen atom, an alkyl group or an acyl group;
• Pf represents the structure (ii), when a plurality of Pf's are present, each Pf may be the same as or different from every other Pf or a plurality of Pf's may combine with each other to form a ring, in the case where a plurality of Pf's combine with each other to form a ring, a combined Pf's may represent the structure (iii) and in this case, * in formula (c) of the structure (iii) represents a bond to R1, R2 or RL;
• Pf3 has the same meaning as Pf3 in formula (c) where z is 2;
• R1 represents an (n+1)-valent organic group;
• R11 represents a divalent organic group, and when a plurality of R11's are present, each R11 may be the same as or different from every other R11;
• R2 represents a single bond or an (n+1)-valent organic group, and when a plurality of R2′s are present, each R2 may be the same as or different from every other R2;
• W represents a methylene group, an oxygen atom or a sulfur atom;
• each of n and m represents an integer of 1 or more, and in the case where R2 in formula (I-2), (I-3), (I-8) or (I-10) represents a single bond, n is 1;
• 1 represents an integer of 0 or more;
• Li represents a linking group represented by —COO—, —OCO—, —CONH—, —O—, —Ar—, —SO3- or —SO2NH—, wherein Ar represents a divalent aromatic ring group, and when a plurality of L1's are present, each L1 may be the same as or different from every other L1;
• each R independently represents a hydrogen atom or an alkyl group;
• R0 represents a hydrogen atom or an organic group;
• L3 represents an (m+2)-valent linking group;
• RL represents an (n+1)-valent linking group, and when a plurality of RL's are present, each RL may be the same as or different from every other RL;
• Rs represents a substituent, and when a plurality of Rs's are present, each Rs may be the same as or different from every other Rs or a plurality of Rs's may combine with each other to form a ring;
• p represents an integer of 0 to 3;
• and
• q is a repetition number of the group represented by -R11-L1- and represents an integer of 0 to 3.

A pattern forming method, comprising:

• (i) forming a film from a chemical amplification resist composition that contains (A) a resin capable of increasing a polarity of the resin (A) to decrease a solubility of the resin (A) for a developer containing an organic solvent by an action of an acid, (B) a compound capable of generating an acid upon irradiation with an actinic ray or radiation, and (C) a solvent;
• (ii) exposing the film;
• and
• (iii) performing development by using a developer containing an organic solvent,
• wherein:
• the content of the resin (A) is from 30 to 99 mass % based on the entire solids content of the resist composition,
• the resin (A) has a structure in which a polar group is protected with a leaving group capable of decomposing and leaving by an action of an acid;
• the leaving group contains a fluorine atom;
• the structure in which a polar group is protected with a leaving group capable of decomposing and leaving by an action of an acid is:
• (i) a structure represented by the following formula (a), which decomposes by an action of an acid to generate a carboxyl group;
• (ii) a structure represented by the following formula (b), which decomposes by an action of an acid to generate one alcoholic hydroxyl group;
• or
• (iii) a structure represented by the following formula (c), which decomposes by an action of an acid to generate two or three alcoholic hydroxyl groups:
• wherein each of Pfl and Pf2 independently represents a monovalent fluorine atom-containing group capable of decomposing and leaving by an action of an acid;
• Pf3 represents a z-valent fluorine atom-containing group capable of decomposing and leaving by an action of an acid;
• z represents 2 or 3;
• and
• * represents a bond to a main chain or side chain of the resin (A);
• and
• the resin (A) contains a repeating unit represented by any one of the following formulae (I-1) and (I-4) to (I-10):
• wherein each Ra independently represents a hydrogen atom, an alkyl group or a group represented by —CH2—O—Ra2, wherein Rae represents a hydrogen atom, an alkyl group or an acyl group;
• Pf represents the structure (i) or (ii), when a plurality of Pf's are present, each Pf may be the same as or different from every other Pf or a plurality of Pf's may combine with each other to form a ring, in the case where a plurality of Pf's combine with each other to form a ring, a combined Pf's may represent the structure (iii) and in this case, * in formula (c) of the structure (iii) represents a bond to R1, R2 or RL;
• Pf3 has the same meaning as Pf3 in formula (c) where z is 2;
• R1 represents an (n+1)-valent organic group;
• R11 represents a divalent organic group, and when a plurality of R11's are present, each R11 may be the same as or different from every other R11;
• R2 represents a single bond or an (n+1)-valent organic group, and when a plurality of R2′s are present, each R2 may be the same as or different from every other R2;
• W represents a methylene group, an oxygen atom or a sulfur atom;
• each of n and m represents an integer of 1 or more, and in the case where R2 in formula (I-2), (I-3), (I-8) or (I-10) represents a single bond, n is 1;
• L1 represents a linking group represented by —COO—, —OCO—, —CONH—, —, —O—, —Ar—, —SO3- or —SO2NH—, wherein Ar represents a divalent aromatic ring group, and when a plurality of Li's are present, each L1 may be the same as or different from every other L1;
• each R independently represents a hydrogen atom or an alkyl group;
• R0 represents a hydrogen atom or an organic group;
• L3 represents an (m+2)-valent linking group;
• RL represents an (n+1)-valent linking group, and when a plurality of RL's are present, each RL may be the same as or different from every other RL;
• Rs represents a substituent, and when a plurality of Rs's are present, each Rs may be the same as or different from every other Rs or a plurality of Rs's may combine with each other to form a ring;
• p represents an integer of 0 to 3;
• and
• q is a repetition number of the group represented by —R11-L1- and represents an integer of 0 to 3;
• wherein the structure in which a polar group is protected with a leaving group capable of decomposing and leaving by an action of an acid is a group represented by the following formula (a-1):
• wherein in formula (a-1), each of Rx1 to Rx3 independently represents a monovalent organic group, provided that at least one member out of Rx1 to Rx3 contains a fluorine atom or a fluorine atom-containing group;
• Rx1 and Rx2 may combine to form a ring, and in this case, at least either Rx3 or the ring formed by combining Rx1 and Rx2 contains a fluorine atom or a fluorine atom-containing group;
• and
• * represents a bond to the main chain or side chain of the resin (A);
• and
• wherein the number of atoms intervening between C#1 and Fad is 2 or more, where C#1 is the tertiary carbon atom denoted by #1 in formula (a-1);
• and Fad is the fluorine atom present at the location closest to C#1 in the leaving group.