US 10,101,653 B2  109  110  trimethylolmethane triglycidyl ether, trimethylolpropane tri› glycidyl  ether,  and triethylolethane  triglycidyl  ether.  Examples of the melamine compound include hexamethylol  melamine, hexamethoxymethyl melamine, hexamethylol  melamine compounds having 1 to 6 methylol groups  methoxymethylated and mixtures thereof, hexamethoxy› ethyl melamine, hexaacyloxymethyl melamine, hexameth› ylol melamine compounds having 1 to 6 methylol groups  acyloxymethylated and mixtures thereof. Examples of the  guanamine compound include tetramethylol guanamine,  tetramethoxymethyl guanamine, tetramethylol guanamine  compounds having 1 to 4 methylol groups methoxymethyl› ated and mixtures thereof, tetramethoxyethyl guanamine,  tetraacyloxyguanamine,  tetramethylol  guanamine  com› pounds having 1 to 4 methylol groups acyloxymethylated  and mixtures thereof. Examples of the glycoluril compound  include tetramethylol glycoluril, tetramethoxyglycoluril,  tetramethoxymethyl  glycoluril,  tetramethylol  glycoluril  compounds having 1 to 4 methylol groups methoxymethyl› ated and mixtures thereof, tetramethylol glycoluril com- pounds having 1 to 4 methylol groups acyloxymethylated  and mixtures thereof. Examples of the urea compound  include  tetramethylol  urea,  tetramethoxymethyl  urea,  tetramethylol urea compounds having 1 to 4 methylol  groups methoxymethylated and mixtures thereof, and  tetramethoxyethyl urea.  Suitable isocyanate compounds include tolylene diisocya› nate, diphenylmethane diisocyanate, hexamethylene diiso› cyanate and cyclohexane diisocyanate. Suitable azide com- pounds  include  1,1’-biphenyl-4,4’-bisazide,  4,4’- methylidenebisazide, and 4,4’-oxybisazide. Examples of the  alkenyl ether group-containing compound include ethylene  glycol divinyl ether, triethylene glycol divinyl ether, 1,2- propanediol divinyl ether, 1,4-butanediol divinyl ether,  tetramethylene glycol divinyl ether, neopentyl glycol divinyl  ether, trimethylol propane trivinyl ether, hexanediol divinyl  ether, 1,4-cyclohexanediol divinyl ether, pentaerythritol  trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tet› ravinyl ether, sorbitol pentavinyl ether, and trimethylol  propane trivinyl ether.  In the negative resist composition, the crosslinker is  preferably added in an amount of 0.1 to 50 parts, more  preferably 1 to 40 parts by weight per 100 parts by weight  of the base polymer.  In the resist composition of the invention, a quencher may  be blended. The quencher is typically selected from con› ventional basic compounds. Conventional basic compounds  include primary, secondary, and tertiary aliphatic amines,  mixed amines, aromatic amines, heterocyclic amines, nitro› gen-containing compounds with carboxyl group, nitrogen- containing compounds with sulfonyl group, nitrogen-con› taining  compounds  with  hydroxyl  group,  nitrogen› containing compounds with hydroxyphenyl group, alcoholic  nitrogen-containing compounds, amide derivatives, imide  derivatives, and carbamate derivatives. Also included are  primary, secondary, and tertiary amine compounds, specifi› cally amine compounds having a hydroxyl, ether, ester,  lactone ring, cyano, or sulfonic acid ester group as described  in JP-A 2008-111103, paragraphs [0146]-[0164], and com› pounds having a carbamate group as described in JP  3 790649. Addition of a basic compound may be effective for  further suppressing the diffusion rate of acid in the resist film  or correcting the pattern profile.  Onium salts such as sulfonium salts, iodonium salts and  ammonium salts of sulfonic acids which are not fluorinated 65  at a-position as described in U.S. Pat. No. 8,795,942 (JP-A  2008-158339) and similar onium salts of carboxylic acid  To the resist composition, a polymeric additive (or water  repellency improver) may also be added for improving the  water repellency on surface of a resist film as spin coated.  The water repellency improver may be used in the topcoat› less immersion lithography. Suitable water repellency  improvers include polymers having a fluoroalkyl group and  polymers having a specific structure with a 1,1,1,3,3,3- hexafluoro-2-propanol residue and are described in JP-A  2007-297590 and JP-A 2008-111103, for example. The  water repellency improver to be added to the resist compo- sition should be soluble in the organic solvent as the  developer. The water repellency improver of specific struc› ture with a 1,1,1,3,3,3-hexafluoro-2-propanol residue is well  soluble in the developer. A polymer having an amino group  or amine salt copolymerized as recurring units may serve as  the water repellent additive and is effective for preventing  evaporation of acid during PEB, thus preventing any hole  pattern opening failure after development.  An  appropriate  amount of the water repellency improver is  O  to 20 parts,  preferably 0.5 to 10 parts by weight per 100 parts by weight  of the base polymer.  The quencher is preferably added in an amount of  O  to 5  parts, more preferably  O  to 4 parts by weight per 100 parts  by weight of the base polymer.  Also useful are quenchers of polymer type as described in  U.S. Pat. No. 7,598,016 (JP-A2008-239918). The polymeric  quencher segregates at the resist surface after coating and  thus enhances the rectangularity of resist pattern. When a  protective film is applied as is often the case in the immer› sion lithography, the polymeric quencher is also effective for  preventing a film thickness loss of resist pattern or rounding  of pattern top.  In formula (2), R  102  and R  103  are each independently  hydrogen, fluorine or trifluoromethyl. R  14  is hydrogen,  hydroxyl, a C$_{1 }$-C$_{35 }$ straight, branched or cyclic monovalent  hydrocarbon group which may contain a heteroatom, or a  substituted or unsubstituted C$_{6}$-C$_{30 }$aryl group.  (2)  R102  R103+C02•  R104  Preferably the anion moiety in the carboxylic acid onium  salt has the formula (2).  In formula (1 ), R  101  is a C$_{1 }$-C$_{40 }$ straight, branched or  cyclic monovalent hydrocarbon group which may contain a  heteroatom.  MA+  is an onium ion such as a sulfonium or  iodonium ion. Suitable sulfonium ions are as exemplified  above as the cation moiety in the sulfonium salt having  formula (1-1 ). Suitable iodonium ions are as exemplified  above as the cation moiety in the iodonium salt having  formula (1-2).  may also be used as the quencher. While an a-fluorinated  sulfonic acid, imide acid, and methide acid are necessary to  deprotect the acid labile group of carboxylic acid ester, an  a-non-fluorinated sulfonic acid and a carboxylic acid are  released by salt exchange with an a-non-fluorinated onium  salt.  An  a-non-fluorinated sulfonic acid and a carboxylic  acid function as a quencher because they do not induce  deprotection reaction.  Also a carboxylic acid onium salt having the formula (1)  is useful as the quencher. 