[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 

## DESCRIPTION OF THE PREFERRED EMBODIMENTS 

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. 

