[0298] (Photosensitive Resist Film) 

[0299] The photosensitive resist film of the present embodiment is obtained by laminating a base film, a pho› tosensitive resin film formed by using the negative type photosensitive resin composition described above, and a cover film in that order. 

[0300] The photosensitive resist film of the present embodiment can be produced, for example, by coating the base film with the negative photosensitive resin composition of the embodiment described above, drying the composition to form a photosensitive resin film, and laminating a cover film on the photosensitive resin film. 

[0301] The base film may be coated with the negative type photosensitive resin composition according to an appropri› ate method using a blade coater, a lip coater, a comma coater, or a film coater. 

[0302] The thickness of the photosensitive resin film is preferably 100 µm or less and more preferably in a range of 5 to 50 µm. 

[0303] As the base film, known films such as a thermo› plastic resin film are used. Examples of this thermoplastic resin include polyesters such as polyethylene terephthalate. The thickness of the base film is preferably in a range of 2 to 150 µm. 

[0304] As the cover film, known films such as a polyeth› ylene film and a polypropylene film are used. As the cover film, a film whose adhesive force to the photosensitive resin film is smaller than that of the base film is preferable. The thickness of the cover film is preferably in a range of 2 to 150 µm, more preferably in a range of 2 to 100 µm, and still more preferably in a range of 5 to 50 µm. 

[0305] The base film and the cover film may be formed of the same film material or different film materials. 

[0306] (Pattern Forming Method) 

[0307] A pattern forming method of the present embodi› ment includes a step of forming a photosensitive resin film on a support (hereinafter, referred to as a "film formation step") using the negative type photosensitive resin compo› sition or the photosensitive resist film of the embodiment described above; a step of exposing the photosensitive resin film (hereinafter, referred to as an "exposure step"); and a step of developing the exposed photosensitive resin film to form a negative type pattern (hereinafter, referred to as a "development step"). 

[0308] The pattern forming method of the present embodi› ment can be performed in the following manner. 

[0309] [Film Formation Step] 

[0310] First, a photosensitive resin film is formed by coating the support with the negative type photosensitive resin composition of the embodiment using a known method such as a spin coating method, a roll coating method, or a screen printing method and performing a bake (post apply bake (PAB)) treatment under a temperature condition of, for example, 50° C. to 150° C. for 2 to 60 minutes. 

[0311] In the film formation step, a photosensitive resin film may be formed on the support by attaching the photo› sensitive resist film to the support. The cover film may be peeled off before the photosensitive resist film is attached to the support. In this manner, the surface of the exposed photosensitive resin film is brought into contact with the support, and the photosensitive resist film is attached to the support. During the attachment, the support or the film may be heated or pressed (laminated) as necessary. After the 

photosensitive resist film is attached to the support, the base film may be peeled off before or after the exposure step described below. 

[0312] The support is not particularly limited and a known support of the related art can be used. For example, sub› strates for electronic components, and such substrates hav› ing predetermined wiring patterns formed thereon can be used. More specific examples thereof include a metal sub› strate such as a silicon wafer, copper, chromium, iron, or aluminum; a glass substrate; and a resin film such as polyethylene terephthalate, polyethylene naphthalate, poly› propylene, or polyethylene. As the materials for the wiring pattern, copper, aluminum, nickel, and gold can be used. 

[0313] Further, as the support, any one of the above› described substrates provided with an inorganic and/or organic film may be used. Examples of the inorganic film include an inorganic antireflection film (inorganic BARC). Examples of the organic film include organic films such as an organic antireflection film ( organic BARC) and a lower layer organic film according to a multilayer resist method. 

[0314] The film thickness of the photosensitive resin film to be formed using the negative type photosensitive resin composition or the photosensitive resist film is not particu› larly limited, but is preferably in a range of 10 to 100 µm. Even in a case where a thick film is formed using the negative type photosensitive resin composition of the embodiment, excellent characteristics are obtained. 

[0315] [Exposure Step] 

[0316] Next, the formed photosensitive resin film is exposed through a mask having a predetermined pattern formed thereon (mask pattern) using a known exposure device or selectively exposed through drawing or the like by performing direct irradiation with electron beams without using a mask pattern therebetween. In addition, a bake (post exposure bake (PEB)) treatment is performed under a tem› perature condition of 80° C. to 150° C. for 40 to 600 seconds and preferably 60 to 300 seconds. 

[0317] The wavelength used in the exposure is not par› ticularly limited, and the exposure is performed by selec› tively radiating (exposing to) radiation, for example, ultra› violet rays having a wavelength of300 to 500 nm, an i-line (wavelength of 365 nm), or visible light rays. As sources of such radiation, a low pressure mercury lamp, a high pressure mercury lamp, an ultra-high pressure mercury lamp, a metal halide lamp, and an argon gas laser can be used. 

[0318] Here, the radiation indicates ultraviolet rays, vis› ible light rays, far ultraviolet rays, X rays, electron beams, or the like. The radiation dose varies depending on the type of each component in the composition, the blending amount thereof, the film thickness of a coating film, and the like. For example, in a case where an ultra-high pressure mercury lamp is used, the radiation does thereof is in a range of 100 to 2000 mJ/cm 2 . 

[0319] The photosensitive resin film may be exposed through typical exposure ( dry exposure) performed in air or an inert gas such as nitrogen or through liquid immersion exposure (liquid immersion lithography). 

[0320] The photosensitive resin film after the exposure step is highly transparent, and the haze value at the time of irradiation with an i-line (wavelength of 365 nm) is prefer› ably 3% or less and more preferably in a range of 1.0% to 2.7%. 

[0321] As described above, the photosensitive resin film formed using the negative photosensitive resin composition 

