Jul. 21, 2016  3  US 2016/0209749 Al  [0042]  FIG.  2  is a schematic diagram for explaining a sec› tional shape of a line pattern of a first line-and-space pattern.  [0043]  FIG.  3A  is a part of a process diagram for explaining  a pattern forming method and a method for forming a pat› terned mask of the present invention.  [0044]  FIG.  3B  is a part of the process diagram for explain› ing the pattern forming method and the method for forming a  patterned mask of the present invention.  [0045]  FIG.  3C  is a part of the process diagram for explain› ing the pattern forming method and the method for forming a  patterned mask of the present invention.  [0046]  FIG.  3D  is a part of the process diagram for explain› ing the pattern forming method and the method for forming a  patterned mask of the present invention.  [0047]  FIG.  3E  is a part of the process diagram for explain› ing the pattern forming method and the method for forming a  patterned mask of the present invention.  [0048]  FIG.  4  is a schematic diagram for explaining a rising  angle of a silicon oxide film in the evaluation method used in  examples.  [0049]  Regarding the description ofa group ( atomic group)  in the present specification, when the description does not  indicate whether a group is substituted or unsubstituted, the  description includes both a group having a substituent and a  group not having a substituent. For example, "alkyl group"  includes not only an alkyl group (an unsubstituted alkyl  group) which does not have a substituent, but also an alkyl  group (a substituted alkyl group) which has a substituent.  [0050]  Moreover, the term "active light" or "radiation"  described here refers to, for example, a bright line spectrum of  a mercury lamp, far-ultraviolet rays represented by an exci› mer laser, extreme ultraviolet rays (EUV light), X-rays, an  electron beam (EB), or the like. In addition, the light in the  present invention refers to the active light or the radiation.  [0051]  In addition, the term "exposure" described here  includes not only the exposure performed using a mercury  lamp, far-ultraviolet rays represented by an excimer laser,  X-rays, or EUV light, but also drawing performed using a  particle beam such as an electron beam, an ion beam, or the  like, unless otherwise specified.  [0052]  Hereinafter, embodiments of the present invention  will be described in detail.  [0053]  In a pattern forming method in which a resist pattern  is formed on a substrate by a photoresist process, and a silicon  oxide film is formed on this resist pattern by a CVD method,  and a method for forming a patterned mask including this  pattern forming method, the resist pattern is exposed to a  temperature higher than the glass transition temperature (Tg)  of a resin configuring the resist pattern. Therefore, as  described above, the resist pattern is reduced to become a skirt  shape, and as a result of inclination of the side wall, there is a  problem that a pattern mask formed of a silicon oxide film  obtained by removing the resist pattern is inclined with  respect to the substrate interface, and pattern collapse is likely  to occur.  [0054]  In the pattern forming method and the method for  forming a patterned mask of the present invention to solve the  above problems, the top width of a line pattern in a line-and› space pattern (hereinafter, also referred to as a "first line-and› space pattern" or a "resist pattern") after exposure and devel› opment, and before film formation, which is formed of the  active light-sensitive or radiation-sensitive resin composition  is larger than the bottom width thereof.  [0055]  The present inventors found that, in general, a sec› tional shape of a line pattern is preferably a rectangle, but, in  the pattern forming method including a film formation step by  a CVD method or the like with respect to a line pattern, the  problem of pattern collapse described above in a line pattern  of a rectangular shape cannot be dissolved. That is, as exem› plified in FIG.  lA,  when the sectional shape of a resist pattern  201a $_{1 }$ before film formation is a rectangle, the resist pattern is  reduced by film formation by CVD or the like, and the sec› tional shape becomes a skirt shape of which the top width is  smaller than the bottom width. As a result, the coating film of  the side wall portion of a resist pattern  20la$_{2 }$ is inclined, a  pattern (pattern mask)  401  ’a  formed of the coating film of the  side wall portion obtained after removal of the resist pattern  20la$_{2 }$ is inclined with respect to the substrate interface, and  this causes pattern collapse.  [0056]  In contrast, in the pattern used in the method of the  present invention, as exemplified in FIG.  lB,  the sectional  shape ofa resist pattern  20lb$_{1 }$ before film formation is a shape  (hereinafter, also referred to as a "T-top shape") of which the  top width is larger than the bottom width. In this case, the  sectional shape of a resist pattern  20lb$_{2 }$ after film formation  by CVD or the like does not become a skirt shape, and the  coating film of the side wall portion of the resist pattern  20lb$_{2 }$ becomes perpendicular with respect to the substrate interface.  As a result, a pattern (pattern mask)  401’b  formed of the  coating film of the side wall portion obtained after removal of  the resist pattern  20lb$_{2 }$ becomes perpendicular with respect  to the substrate interface, and the pattern collapse is  improved.  [0057]  That is, in one aspect, the present invention is a  pattern forming method which includes (I) a step of forming  a first film by applying an active light-sensitive or radiation› sensitive resin composition which contains (A) a resin having  a repeating unit having a group that is decomposed by the  action of an acid and generates a polar group and (B) a  compound that generates an acid by irradiation with active  light or radiation to a substrate, (II) a step of exposing the first  film, (III) a step of forming a first line-and-space pattern by  developing the exposed first film, and (IV) a step of coating  the first line-and-space pattern with a second film, in which  the top width of the line pattern of the first line-and-space  pattern formed in Step (III) is larger than the bottom width  thereof.  [0058]  In another aspect, the present invention is a method  for forming a patterned mask which includes (I) a step of  forming a first film by applying an active light-sensitive or  radiation-sensitive resin composition which contains (A) a  resin having a repeating unit having a group that is decom› posed by the action of an acid and generates a polar group and  (B) a compound that generates an acid by irradiation with  active light or radiation to a substrate, (II) a step of exposing  the first film, (III) a step of forming a first line-and-space  pattern by developing the exposed first film, (IV) a step of  coating the first line-and-space pattern with a second film, (V)  a step ofremoving the second film of the upper surface and the  space portion of the line pattern in the first line-and-space  pattern and leaving the second film only on the side wall of the  line pattern, and (VI) a step of forming a second line-and› space pattern by removing the line pattern, in which the top  width of the line pattern of the first line-and-space pattern  formed in Step (III) is larger than the bottom width thereof.  DESCRIPTION OF THE PREFERRED  EMBODIMENTS 