US 2007/0072121 Al  25  Mar. 29, 2007  merization process ( also called an oligomer process) may be  used. The fluoro-aliphatic compound can be synthesized by  the method described in JP-A-2002-90991.  682. Specific examples of the photo-base generator which  can be suitably used include 2-nitrobenzyl carbamate, 2,5- dinitro benzy lcyclohexyl carbamate, N-cyclohexy 1-4-meth› y lpheny !sulfonamide and  1, 1-dimethy 1-2-pheny lethy 1-N› isopropy l carbamate. Such a photo-base generator is added  for the purpose of improving the resist profile or the like.  [0136]  The polymer having a fluoro-aliphatic group is  preferably a copolymer of a fluoro-aliphatic group-contain› ing monomer with a (poly(oxyalkylene)) acrylate and/or a  (poly(oxyalkylene)) methacrylate, and the polymer may  have an irregular distribution or may be a block copolymer.  Examples of the poly(oxyalkylene) group include a poly  (oxyethylene) group, a poly (oxypropylene) group and a  poly (oxybutylene) group. This group may also be a unit  having alkylenes differing in the chain length within the  same chain, such as block-linked poly(oxyethylene, oxypro› pylene and oxyethylene) andblock-linked poly(oxyethylene  and oxypropylene ). Furthermore, the copolymer of a fluoro› aliphatic group-containing monomer with a (poly(oxyalky› lene)) acrylate (or methacrylate) may be not only a binary  copolymer but also a ternary or higher copolymer obtained  by simultaneously copolymerizing two or more different  fluoro-aliphatic group-containing monomers or two or more  different (poly(oxyalkylene)) acrylates (or methacrylates).  [0137]  Examples thereof include commercially available  surfactants such as Megafac F178, F-470, F-473, F-475,  F-476 and F-472 (produced by Dainippon Ink & Chemicals,  Inc.), and further include a copolymer of an acrylate (or  methacrylate) having a C$_{6}$F $_{13 }$ group with a (poly-( oxyalky› lene )) acrylate ( or methacrylate ), a copolymer of an acrylate  ( or methacrylate) having a C$_{6}$F $_{13 }$ group with (poly( oxyeth› ylene )) acrylate (or methacrylate) and (poly-(oxypropy› lene )) acrylate ( or methacrylate ), a copolymer of an acrylate  ( or methacrylate) having a C$_{8}$F $_{17 }$ group with a (poly( oxy› alkylene )) acrylate ( or methacrylate ), and a copolymer of an  acrylate ( or methacrylate) having a C$_{8}$F $_{17 }$group with (poly› ( oxyethylene )) acrylate (or methacrylate) and (poly(oxypro› pylene)) acrylate (or methacrylate).  [0138]  The amount of the surfactant used is preferably  from 0.0001 to 2 mass %, more preferably from 0.001 to 1  mass  %, based on the entire amount of the positive resist  composition (excluding the solvent).  [0139]  The positive resist compos1t10n of the present  invention may further contain, if desired, a dye, a photo-base  generator and the like.  [0141]  A suitable dye includes an oily dye and a basic dye.  Specific examples thereof include Oil Yellow #101, Oil  Yellow #103, Oil Pink #312, Oil Green BG, Oil Blue BOS,  Oil Blue #603, Oil Black BY, Oil Black BS, Oil Black T-505  (all produced by Orient Chemical Industries Co., Ltd.),  Crystal  Violet  (CI42555),  Methyl  Violet  (CI42535),  Rhodamine B (CI45170B), Malachite Green (CI42000) and  Methylene Blue (CI52015).  [0142]  Examples of the photo-base generator which can be  added to the composition of the present invention include  the compounds described in JP-A-4-151156,  JP-A-4- 162040,  JP-A-5-197148,  JP-A-5-5995,  JP-A-6-194834,  JP-A-8-146608, JP-A-10-83079 and European Patent 622,  [0143]  The resist composition of the present invention is  dissolved in a solvent capable of dissolving respective  components described above and then coated on a support.  Usually, the concentration is, in terms of the solid content  concentration of all resist components, preferably from 2 to  30 mass %, more preferably from 3 to 25 mass %.  [0144]  Preferred examples of the solvent used here include  ethylene dichloride, cyclohexanone, cyclopentanone, 2-hep› tanone, y-butyrolactone, methyl ethyl ketone, ethylene gly› col monomethyl ether, ethylene glycol monoethyl ether,  2-methoxyethyl acetate, ethylene glycol monoethyl ether  acetate, propylene glycol monomethyl ether, propylene gly› col monomethyl ether acetate, toluene, ethyl acetate, methyl  lactate, ethyl lactate, methyl methoxypropionate, ethyl  ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl  pyruvate,  N,N-dimethylformamide,  dimethylsulfoxide,  N-methylpyrrolidone and tetrahydrofuran. One of these sol› vents is used alone, or several species thereof are mixed and  used.  [0145]  The positive resist composition of the present  invention is coated on a substrate to form a thin film. The  thickness of this coating film is preferably from 0.05 to 4.0  µm.  [0146]  In the present invention, a commercially available  inorganic or organic antireflection film may be used, if  desired. Furthermore, an antireflection film may be used by  coating it as an underlayer of the resist.  [0147]  The antireflection film used as the underlayer of the  resist may be either an inorganic film type such as titanium,  titanium dioxide, titanium nitride, chromium oxide, carbon  and amorphous silicon, or an organic film type comprising  a light absorbent and a polymer material. The former  requires equipment for the film formation, such as vacuum  deposition apparatus, CVD apparatus and sputtering appa› ratus. Examples of the organic antireflection film include a  film comprising a diphenylamine derivative and formalde› hyde-modified melamine resin condensate, an alkali-soluble  resin and a light absorbent described in JP-B-7-69611 (the  term "JP-B" as used herein means an "examined Japanese  patent publication"), a reaction product of a maleic anhy› dride copolymer and a diamine-type light absorbent  described in U.S. Pat. No. 5,294,680, a film comprising a  resin binder and a methylolmelamine-based heat crosslink› ing agent described in JP-A-6-118631, an acrylic resin-type  antireflection film containing a carboxylic acid group, an  epoxy group and a light absorbing group within the same  molecule described in JP-A-6-118656, a film comprising  methylolmelamine and a benzophenone-based light absor› bent described in JP-A-8-87115, and a film obtained by  adding a low molecular light absorbent to a polyvinyl  alcohol resin described in JP-A-8-179509.  [0148]  Also, the organic antireflection film may be a  commercially available organic antireflection film such as  [ 5] Other components  [0140]  In the present invention, a dye may be used.  3. Solvents  1. Dye  2. Photo-base generator 