In addition, in the resist composition (2), if desired, mis› cible additives, for example, an additional resin for improving  the performance of the resist film, a dissolution inhibitor, a  plasticizer, a stabilizer, a coloring agent, a halation inhibitor,  a dye, and the like can be properly added and contained.  The resist composition (2) can be manufactured by dissolv› ing the resist materials in an organic solvent. As the organic 55  solvent, the same component (S) as that described above can  be used in the same manner.  According to the resist composition of the invention, it is  possible to form a resist pattern whose roughness is  decreased, while maintaining good sensitivity.  In the invention, the resist composition has a partial struc› ture represented by the general formula (a0-r-1) therein. In  the partial structure represented by the general formula ( a0- r-1 ), the anion moiety thereof becomes an appropriate weakly  acidic anion upon exposure to exhibit a quenching (acid dif- fusion control) effect to thus trap the acid generated upon  exposure. Accordingly, in the formation of a resist pattern, the  Examples of the fluorine additive include the same com› ponent (F) as that which may be used in the resist composition  (1 ).  The compound (E) is the same as the component (E) which  may be used in the resist composition (1 ).  Examples of the acid diffusion control agent component  include the same component (D2) and component (D3) as  those which may be used in the resist composition (1 ).  Examples of other components include an acid diffusion  control agent component; at least one kind of compound (E)  selected from the group consisting of an organic carboxylic  acid and a phosphorus oxo acid or a derivative thereof; and a  fluorine additive.  The resist composition (2) may further contain other com› ponents in addition to the base material component and the  component (B).  The acid generator component (B) used in the resist com› position (2) is the same as the component (B) used in the resist  composition (1).  Other Components  In the resist composition (2), the content of the base mate› rial component may be adjusted in conformity with the thick› ness of the resist film to be formed, or the like.  Acid Generator Component (B): Component (B)  A degree of dispersion (Mw/Mn) of the component (A2) is  not particularly limited, and is preferably 1.0 to 5.0, more  preferably I.Oto 4.0, and most preferably I.Oto 3.0. It is to be  noted that Mn represents a number average molecular weight.  The component (A2) may be used alone, or in combination  of two or more kinds thereof.  A proportion of the component (A2) in the component (A)  is preferably 25 mass % or more, more preferably 50 mass %  or more, and still more preferably 7 5 mass% or more relative  to a total mass of the component (A), and it may even be 100  mass %. When the proportion is 25 mass % or more, a resist  pattern which is excellent in various lithography properties  such as an increase of sensitivity and an improvement of  roughness is easily formed.  In the resist composition (2), regarding the component (A),  a base material component ( component ( A3)) which does not  fall under the definition of the component (A2) and exhibits  changed solubility in a developing solution by the action of an  acid may be used in combination. The component (A3) is the  same as the above-described component (A3), and may be  used alone, or in combination of two or more kinds thereof.  In the resist composition (2), the base material component  may be used alone, or in combination of two or more kinds  thereof.  diffusion of the acid generated upon exposure is suppressed  and the roughness of the resist pattern is thus decreased. In  addition, even when a component having the partial structure  is different from the base material component, the partial  structure has a polar group (carbonyloxy group----C(=O)› O-), and thus an interaction acts between the component  having the partial structure and the base material component  and uniform distribution easily occurs in the resist film. How› ever, when the blending amount of the component having the  partial structure is large, sensitivity tends to decrease.  In the invention, the resist composition contains a high› molecular weight compound which has a partial structure  represented by the general formula (a0-r-1) and has a con- stituent unit (a0) having an imide group in a side chain. Due  to the combination of the partial structure with the constituent  unit ( a0), a significant roughness decreasing effect is obtained  in the formation of a resist pattern and a decrease of sensitivity  is suppressed. Thus, good sensitivity is maintained.  Furthermore, in the formation of a resist pattern using the  resist composition of the invention, an exposure margin (EL  margin) as an index of a variation in pattern size associated  with a fluctuation of the exposure amount, which is difficult to  balance with a decrease of roughness, is good.  Resist Pattern Forming Method  A resist pattern forming method of a second aspect of the  invention includes a step of forming a resist film on a support  using a resist composition of the first aspect of the invention,  a step of exposing the resist film, and a step of developing the  resist film after the exposure to form a resist pattern.  For example, the resist pattern forming method of this  aspect can be performed as follows.  First, the resist composition according to the first aspect is  applied to a support using a spinner or the like, and a baking  (post applied bake (PAB)) treatment is conducted under a  temperature condition of, for example, 80°  C. to 150°  C. for  40 to 120 seconds, and preferably 60 to 90 seconds, thereby  forming a resist film.  Subsequently, using an exposure apparatus, for example,  anArF exposure apparatus, an electron beam drawing appa› ratus, or an EUV exposure apparatus, the resist film is  exposed through a mask having a predetermined pattern  formed thereon (mask pattern) or selectively exposed without  using a mask pattern by drawing by means of direct irradia- tion with electron beams, or the like. Then, a baking (post  exposure bake (PEB)) treatment is conducted under a tem› perature condition of, for example, 80°  C. to 150°  C. for 40 to  120 seconds, and preferably 60 to 90 seconds.  Subsequently, the resist film is subjected to a development  treatment. In the case of an alkali development process, an  alkali developing solution is used to perform the development  treatment, and in the case of a solvent development process, a  developing solution containing an organic solvent ( organic  developing solution) is used to perform the development  treatment.  After the development treatment, a rinse treatment is pref› erably performed. In the rinse treatment, in the case of an  alkali development process, water rinsing using pure water is  preferable, and in the case of a solvent development process,  a rinse solution containing an organic solvent is preferably  used.  In the case of the solvent development process, after the  development treatment or the rinse treatment, a treatment of  removing the developing solution or rinse solution deposited  on the pattern with a supercritical fluid may be conducted.  After the development treatment or the rinse treatment,  drying is performed. In some cases, a baking treatment (post- US 9,052,592 B2  130  129 