US 9,097,971 B2  204  203  one terminal of the main chain thereof, and hence, exhibits a  function of generating acid upon exposure.  For example, the group represented by the general formula  (anl) and the terminal group (I-1) have a sulfonium salt  portion at the terminal thereof, thereby generating sulfonic  acid upon exposure.  Therefore, it is presumed that, acid is generated from the  terminal of the polymeric compound at exposed portions, and  sensitivity can be improved.  Further, it is presumed that, in the case where the polymeric  compound has a group which exhibits a function of generat› ing acid, the excess diffusion of acid generated can be sup› pressed, as compared to the case where the acid generator of  low-molecular compound as exemplified above as a compo› nent (B) is used alone.  The anion portions at the terminal of the main chain, which  generate acid upon exposure, is uniformly distributed within  the resist film, and at exposed portions, acid is generated  uniformly from the anion portions. As a result, at exposed  portions, the acid decomposable group in the polymeric com› pound (Al) is likely to be decomposed uniformly.  In the case where the polymeric compound contained in the  resist composition of the fifth aspect of the present invention  is the component (Al’) which exhibits changed solubility in a  developing solution by the action of acid, the terminal group  (I-1) which generates acid upon exposure is uniformly dis› tributed within the resist film together with the component  (Al’).  It  is presumed that acid is uniformly generated from the  terminal group (I-1) at exposed portions, so that the acid  decomposable groups within the component (Al’) is uni› formly cleaved at exposed portions, thereby achieving the  aforementioned effects. The component (Al’) has a group  (I-1) which generates acid upon exposure, and the acid  decomposable group and acid generated are present in rela› tively close.  It  is presumed that a decomposition reaction by  the action of acid is likely to proceed, thereby improving the  aforementioned effect.  In the case where the polymeric compound contained in the  resist composition of the seventh aspect of the present inven› tion is the component (Al) which exhibits increased polarity  by the action of acid, the acid decomposable group and acid  generated from the anion portion are present in relatively  close. As a result, a decomposition reaction of the acid  decomposable group is likely to proceed by the action of acid,  Furthermore, the polymeric compound contained in the  resist composition of the seventh aspect of the present inven› tion includes the component (C) which functions as a  quencher, in addition to the polymeric compound (Al).  It  is  presumed that the component (C) lose the function as a  quencher at exposed portions, thereby making a large contrast  of concentration of acid between the exposed portions and the  unexposed portions, and enabling formation of a pattern with  excellent shape and lithography properties.  <<Method of Forming a Resist Pattern>>  The method of forming a resist pattern according to the  sixth aspect and eighth aspect of the present invention  includes: forming a resist film on a substrate using a resist  composition of the fifth aspect of the present invention; con› ducting exposure of the resist film; and developing the resist  film to form a resist pattern.  The method for forming a resist pattern according to the  present invention can be performed, for example, as follows.  Firstly, a resist composition is applied onto a substrate  using a spinner or the like, and a prebake (post applied bake  (PAB)) is conducted under temperature conditions of 80 to  150°  C. for 40 to 120 seconds, preferably 60 to 90 seconds to  form a resist film. Then, for example, either by exposure with  The multilayer resist method is broadly classified into a  method in which a double-layer structure consisting of an  upper-layer resist film and a lower-layer organic film is  formed ( double-layer resist method), and a method in which  a multilayer structure having at least three layers consisting of  More specifically, in the multilayer resist method, a desired  thickness can be ensured by the lower-layer organic film, and  as a result, the thickness of the resist film can be reduced, and  an extremely fine pattern with a high aspect ratio can be  formed.  Here, a "multilayer resist method" is method in which at  least one layer of an organic film (lower-layer organic film)  and at least one layer of a resist film (upper resist film) are  provided on a substrate, and a resist pattern formed on the  upper resist film is used as a mask to conduct patterning of the  lower-layer organic film. This method is considered as being  capable of forming a pattern with a high aspect ratio.  Further, as the substrate, any one of the above-mentioned  substrates provided with an inorganic and/or organic film on  the surface thereof may be used. As the inorganic film, an  inorganic anti-reflection film (inorganic BARC) can be used.  As the organic film, an organic antireflection film ( organic  BARC) and an organic film such as a lower-layer organic film  used in a multilayer resist method can be used.  The substrate is not specifically limited and a convention› ally known substrate can be used. For example, substrates for  electronic components, and such substrates having wiring  patterns formed thereon can be used. Specific examples of the  material of the substrate include metals such as silicon wafer,  copper, chromium, iron and aluminum; and glass. Suitable  materials for the wiring pattern include copper, aluminum,  nickel, and gold.  Thereafter, drying is conducted.  If desired, bake treatment  (post bake) can be conducted following the developing. In  this manner, a resist pattern that is faithful to the mask pattern  can be obtained.  In the case of a solvent developing process, after the devel› oping treatment or the rinsing, the developing solution or the  rinse liquid remaining on the pattern can be removed by a  treatment using a supercritical fluid.  After the developing treatment, it is preferable to conduct a  rinse treatment. In the case of an alkali developing process, it  is preferable to conduct a water rinse using pure water. In the  case of a solvent developing process, it is preferable to use a  rinse liquid containing the aforementioned organic solvent.  Alternatively, in the case of a solvent developing process,  an organic solvent is used to perform a developing treatment.  As the organic solvent, any of the conventional organic sol› vents can be used which are capable of dissolving the com› ponent (A) (prior to exposure). Specific examples of the  organic solvent include polar solvents such as ketone sol› vents, ester solvents, alcohol solvents, amide solvents and  ether solvents, and hydrocarbon solvents. Among these, ester  solvents are preferable. As an ester solvent, butyl acetate is  preferable.  In the case of an alkali developing process, an alkali devel- oping solution such as a 0.1 to 10% by weight aqueous solu› tion oftetramethylammonium hydroxide (TMAH) is used to  perform an alkali developing treatment.  an ArF excimer laser or an electron beam (EB) through a  desired mask pattern using an ArF exposure apparatus or an  electron beam lithography apparatus, or by patterning via  direct irradiation with an electron beam without using a mask  pattern, followed by post exposure bake (PEB) under tem› perature conditions of 80 to 150°  C. for 40 to 120 seconds,  preferably 60 to 90 seconds. Subsequently, the resist film is  subjected to a developing process. 