148  US 9,217,919 B2  147  mass relative to the whole amount ( excluding the solvent) of  the positive working resist composition.  <Acid-decomposable Dissolution-inhibiting Compound>  The positive working resist composition of the invention  can contain a dissolution-inhibiting compound having a  molecular weight of not more than 3,000, which is capable of  decomposing by the action of an acid to increase its solubility  in an alkali developer (this compound will also be referred to  as "dissolution-inhibiting compound").  As the dissolution-inhibiting compound, an acid-decom› posable group-containing alicyclic or aliphatic compound,  such as acid-decomposable group-containing cholic acid  derivatives described in  Processing of SPIE,  2724, 355  (1996), is preferable. With respect to the acid-decomposable  group and the alicyclic structure, the same as described above  in the acid-decomposable resin can be referred to herein.  In case of irradiating the positive working resist composi› tion of the invention with an electron beam, a compound  containing a structure where a phenolic hydroxyl group of a  phenol compound is substituted with an acid-decomposable  group is preferable. The phenol compound is preferably a  phenol compound containing from 1 to 9 phenol skeletons,  and more preferably a phenol compound containing from 2 to  6 phenol skeletons.  In the invention, a molecular weight of the dissolution› inhibiting compound is not more than 3,000, preferably from  300 to 3,000, and more preferably from 500 to 2,500.  The addition amount of the dissolution-inhibiting com- pound is preferably from  O  to 50% by mass, and more pref› erably from  O  to 40% by mass relative to the total solids  content of the positive working resist composition.  Specific examples of the dissolution-inhibiting compound  are given below, but it should not be construed that the inven- tion is limited thereto.  which are manufactured by Jemco Inc.); PF 636, PF 656, PF  6320 and PF 6520 (all of which are manufactured by  OMNOVA Solutions Inc.); and FTX-204D, FTX-208G,  FTX-218G, FTX-230G, FTX-204D, FTX-208D, FTX- 212D, FTX-218 and FTX-222D (all of which are manufac- tured by NEOS Company Limited). Also, a polysiloxane  polymer, KP-341 (manufactured by Shin-Etsu Chemical Co.,  Ltd.) can also be used as the silicon based surfactant.  Also, as the surfactant, in addition to the foregoing known  surfactants, surfactants using a polymer having a fluoro ali- phatic group derived from fluoro aliphatic compounds manu› factured by a telomerization method (also called a telomer  method) or an oligomerization method (also called an oligo› mer method) can be used. The fluoro aliphatic compound can  be synthesized according to the method disclosed in JP-A- 2002-90991.  As the polymer having a fluoro aliphatic group, copoly› mers of a fluoro aliphatic group-containing monomer and a  (poly(oxyalkylene)) acrylate and/or a (poly(oxyalkylene))  methacrylate are preferable; and these monomers may be  irregularly distributed or block copolymerized. Also,  examples of the poly( oxyalkylene) group include a poly( oxy› ethylene) group, a poly( oxypropylene) group and a poly( oxy› butylene) group. A unit containing alkylenes having a differ› ent chain length within the same chain length, such as poly  ( oxyethylene/oxypropylene/oxyethylene block connected  body) and poly(oxyethylene/oxypropylene block connected  body) may also be used. Furthermore, the copolymer of a  fluoro aliphatic group-containing monomer and a (poly( oxy› alky lene)) a cry late ( or methacry late) may be not only a binary  copolymer but a ternary or multi-component copolymer  obtainable by simultaneous copolymerization of two or more  kinds of different fluoro aliphatic group-containing mono› mers or two or more kinds of different (poly(oxyalkylene))  acrylates (or methacrylates).  Examples of commercially available surfactants include  MEGAFAC F178, MEGAFAC F-470, MEGAFAC F-473,  MEGAFAC F-475, MEGAFAC F-476 and MEGAFAC  F-472 (all of which are manufactured by DIC Corporation).  Furthermore, examples of the surfactant include a copolymer  of a C$_{6}$F $_{13 }$group-containing acrylate ( or methacrylate) and a  (poly( oxyalkylene )) acrylate ( ormethacrylate ); and a copoly› mer of a C$_{3}$F$_{7 }$ group-containing acrylate (or methacrylate),  (poly( oxyethylene )) acrylate ( or methacrylate) and (poly( ox- ypropylene)) acrylate (or methacrylate).  Also, in the invention, other surfactants than the fluorine  based and/or silicon based surfactant can also be used. Spe› cific examples thereof include nonionic surfactants such as  polyoxyethylene alkyl ethers (for example, polyoxyethylene  lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene  cetyl ether and polyoxyethylene oleyl ether), polyoxyethyl› ene alkylaryl ethers (for example, polyoxyethylcne octylphe› nyl ether and polyoxyethylene nonylphenyl ether), polyoxy› ethylene/polyoxypropylene block copolymers, sorbitan fatty  acid esters (for example, sorbitan monolaurate, sorbitan  monopalmitate, sorbitan monostearate, sorbitan monooleate,  sorbitan trioleate and sorbitan tristearate) and polyoxyethyl› ene sorbitan fatty acid esters (for example, polyoxyethylene  sorbitan monolaurate, polyoxyethylene sorbitan monopalmi- tate, polyoxyethylcne sorbitan monostearate, polyoxyethyl› ene sorbitan trioleate and polyoxyethylene sorbitan tristear- ate ).  Such a surfactant may be used singly or may be used in  combinations of several kinds thereof.  The use amount of the surfactant is preferably from 0.0001  to 2% by mass, and more preferably from 0.001 to 1 % by  HO  COO-t-Bu  HO  OH  0  -o+o- 0  t-Bu...._ O ~0  00 O _,,,t-Bu  0  HO 