Sep. 10,2020  65  US 2020/0285149 Al  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.  [0157]  In the negative resist composition, the crosslinker  is preferably added in an amount of 0 to 50 parts, more  preferably 1 to 40 parts by weight per 100 parts by weight  of the base polymer.  [0158]  In the resist composition of the invention, a  quencher other than the inventive iodized aromatic N-car› bonylsulfonamide salt may be blended. The other quencher  is typically selected from conventional basic compounds.  Conventional basic compounds include primary, secondary,  and tertiary aliphatic amines, mixed amines, aromatic  amines, heterocyclic amines, nitrogen-containing com› pounds with carboxyl group, nitrogen-containing com› pounds with sulfonyl group, nitrogen-containing com› pounds  with  hydroxyl  group,  nitrogen-containing  compounds with hydroxyphenyl group, alcoholic nitrogen› containing compounds, amide derivatives, imide deriva› tives, and carbamate derivatives. Also included are primary,  secondary, and tertiary amine compounds, specifically  amine compounds having a hydroxyl group, ether bond,  ester bond, lactone ring, cyano group, or sulfonic acid ester  bond as described in JP-A 2008-111103, paragraphs [0146]› [0164], and compounds 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.  [0159]  Onium salts such as sulfonium salts, iodonium salts  and ammonium salts of sulfonic acids which are not fluo› rinated at a-position as described in U.S. Pat. No. 8,795,942  (JP-A 2008-158339) and similar onium salts of carboxylic  acid may also be used as the other 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 carbox› ylic 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.  [0160]  Also useful are quenchers of polymer type as  described in U.S. Pat. No. 7,598,016 (JP-A 2008-239918).  The polymeric quencher segregates at the resist surface after  coating and thus enhances the rectangularity of resist pat› tern. When a protective film is applied as is often the case in  the immersion lithography, the polymeric quencher is also  effective for preventing a film thickness loss of resist pattern  or rounding of pattern top.  [0161]  The other quencher is preferably added in an  amount of 0 to 5 parts, more preferably 0 to 4 parts by  weight per 100 parts by weight of the base polymer. The  other quencher may be used alone or in admixture.  [0162]  Also, an acetylene alcohol may be blended in the  resist composition. Suitable acetylene alcohols are described  in JP-A 2008-122932, paragraphs [0179]-[0182].  An  appro› priate amount of the acetylene alcohol blended is Oto 5 parts  by weight per 100 parts by weight of the base polymer.  [0163]  Pattern Forming Process  [0164]  The resist composition is used in the fabrication of  various integrated circuits. Pattern formation using the resist  composition may be performed by well-known lithography  processes. The process generally involves applying the resist  composition to form a resist film on a substrate, exposing the  resist film to high-energy radiation, and developing the  exposed resist film in a developer.  If necessary, any addi› tional steps may be added.  [0165]  For example, the resist composition is first applied  onto a substrate on which an integrated circuit is to be  formed (e.g., Si, SiO$_{2}$ ,  SiN, SiON, TiN, WSi, BPSG, SOG,  or organic antireflective coating) or a substrate on which a  mask circuit is to be formed ( e.g., Cr, CrO, CrON, M0Si$_{2}$ ,  or SiO$_{2}$ )  by a suitable coating technique such as spin  coating, roll coating, flow coating, dipping, spraying or  doctor coating. The coating is prebaked on a hot plate at a  temperature of 60 to 150°  C. for 10 seconds to 30 minutes,  preferably at 80 to 120°  C. for 30 seconds to 20 minutes. The  resulting resist film is generally 0.1 to 2  µm  thick.  [0166]  The resist film is then exposed to a desired pattern  of high-energy radiation such as UV, deep-UV, EB, EUV of  wavelength 3 to 15 nm, x-ray, soft x-ray, excimer laser light,  y-ray or synchrotron radiation. When UV, deep-UV, EUV,  x-ray, soft x-ray, excimer laser light, y-ray or synchrotron  radiation is used as the high-energy radiation, the resist film  is exposed thereto through a mask having a desired pattern  in a dose of preferably about 1 to 500 mJ/cm 2 ,  more  preferably about 10 to 200 mJ/cm 2 .  When EB is used as the  high-energy radiation, the resist film is exposed thereto  through a mask having a desired pattern or directly in a dose  of preferably about 0.1 to 500 µC/cm 2 ,  more preferably  about 0.5 to 200 µC/cm 2 .  It is appreciated that the inventive  resist composition is suited in micropatterning using KrF  excimer laser, ArF excimer laser, EB, EUV, x-ray, soft x-ray,  y-ray or synchrotron radiation, especially in micropatterning  using EB or EUV.  [0167]  After the exposure, the resist film may be baked  (PEB) on a hot plate or in an oven at 30 to 150°  C. for 10  seconds to 30 minutes, preferably at 50 to 120°  C. for 30  seconds to 20 minutes.  [0168]  After the exposure or PEB, in the case of positive  resist, the resist film is developed in a developer in the form  of an aqueous base solution for 3 seconds to 3 minutes,  preferably 5 seconds to 2 minutes by conventional tech› niques such as dip, puddle and spray techniques. A typical  developer is a 0.1 to 10 wt%, preferably 2 to 5 wt% aqueous  solution of tetramethylammonium hydroxide (TMAH), tet› raethylammonium hydroxide (TEAH), tetrapropylammo› nium hydroxide (TPAH), or tetrabutylammonium hydroxide  (TBAH). The resist film in the exposed area is dissolved in  the developer whereas the resist film in the unexposed area  is not dissolved. In this way, the desired positive pattern is  formed on the substrate. Inversely in the case of negative  resist, the exposed area of resist film is insolubilized and the  unexposed area is dissolved in the developer.  [0169]  In an alternative embodiment, a negative pattern  may be formed via organic solvent development using a  positive resist composition comprising a base polymer hav› ing an acid labile group. The developer used herein is  preferably selected from among 2-octanone, 2-nonanone,  2-heptanone,  3-heptanone,  4-heptanone,  2-hexanone,  3-hexanone,  diisobutyl  ketone,  methylcyclohexanone,  acetophenone, methylacetophenone, propyl acetate, butyl  acetate, isobutyl acetate, pentyl acetate, butenyl acetate,  isopentyl acetate, propyl formate, butyl formate, isobutyl  formate, pentyl formate, isopentyl formate, methyl valerate,  methyl pentenoate, methyl crotonate, ethyl crotonate, 