Conductive film manufacturing method, mask manufacturing method, semiconductor device manufacturing method, conductive film defect inspection method, and defect inspection apparatus

Abstract

According to the present invention, a method for manufacturing a conductive film having high defect detection accuracy is provided. The manufacturing method includes an inspection step in which the conductive film is irradiated with laser light to inspect defects in the conductive film, and in the inspection step, the conductive film is irradiated with laser light having a wavelength such that the extinction coefficient (k) of the conductive film is 0.2 or less.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a conductive film, a method for manufacturing a mask, a method for manufacturing a semiconductor device, a method for inspecting defects of a conductive film, and a defect inspection device. This application claims priority based on Japanese Patent Application No. 2022-146118 filed in Japan on September 14, 2022, the contents of which are incorporated herein by reference. Background Art

[0002] Patterning technology using ionizing radiation such as electron beams and ion beams is expected to be the next generation of photolithography. In the manufacture of semiconductor devices, various patterns are formed on substrates such as wafers by, for example, photolithography using a photomask. When there are defects on the substrate or the photomask, pattern formation is affected, so defect inspection is one of the important processes.

[0003] As a defect inspection method, for example, an inspection method using laser irradiation is known. For example, as a light source for detecting defects of a substrate or a mask, a laser light source generating a laser beam with a wavelength of 532 nm (see Patent Document 1) or illumination light with a wavelength of 504 nm (see Patent Document 2) is used. In addition, with the miniaturization of semiconductors in recent years, short-wavelength light with higher sensitivity for detecting micro defects is used.

[0004] However, in the pattern forming method using ionizing radiation, there is a problem that, particularly when the substrate is insulating, the trajectory of the ionizing radiation is bent due to the electric field generated by the charge of the substrate, making it difficult to obtain a desired pattern. As a method for solving this problem, there is known a technique in which a conductive composition containing a conductive polymer is applied to the surface of a resist layer to form a conductive film, and the surface of the resist layer is covered with the conductive film (see Patent Document 3). Prior art literature Patent Literature]

[0005] Patent Document 1: Japanese Patent Application Publication No. 2008-268041 Patent Document 2: Japanese Patent Application Publication No. 2018-198293 Patent Document 3: International Publication No. 2014 / 017540 Summary of the invention Problems to be solved by the invention

[0006] However, in the conventional defect inspection method, it is difficult to detect defects in the conductive film. An object of the present invention is to provide a method for manufacturing a conductive film with high defect detection accuracy, a method for manufacturing a mask, a method for manufacturing a semiconductor device, a method for inspecting defects of a conductive film, and a defect inspection apparatus. Technical solutions to the problem

[0007] The shorter the wavelength of laser light is, the more likely it is to be scattered when irradiated with defects such as foreign matter or scratches. Therefore, as described in Patent Documents 1 and 2, short-wavelength laser light is generally used to detect minute defects on substrates or masks. However, the present inventors have found that in a conductive film formed on a substrate, the conductive film absorbs laser light, and therefore, even if laser light is irradiated to a defect, it is difficult to scatter the laser light, which makes it difficult to detect the defect. Therefore, the inventors focused on the extinction coefficient k of the conductive film. If the conductive film is irradiated with a laser of a wavelength having an extinction coefficient k of less than 0.2, the laser is less likely to be absorbed by the conductive film, making it easier to detect defects in the conductive film. Based on this idea, the present invention was completed. That is, the present invention has the following aspects.

[0008] [1] A method for manufacturing a conductive film, comprising the following steps: an inspection step of irradiating the conductive film with laser light to inspect defects of the conductive film, In the inspection step, the conductive film is irradiated with laser light having a wavelength at which the extinction coefficient k of the conductive film is 0.2 or less.

[0009] [2] A method for manufacturing a conductive film, comprising the step of irradiating the conductive film with laser light having a wavelength at which an extinction coefficient k of the conductive film is determined to be 0.2 or less to inspect the conductive film for defects.

[0010] [3] The method for producing a conductive film according to [1] or [2], further comprising a film forming step of forming the conductive film on a substrate.

[0011] [4] The method for producing a conductive film according to [1] or [2], wherein the conductive film is formed on a substrate.

[0012] [5] The method for producing a conductive film according to [3], wherein a resist layer is formed on the substrate, The film forming step is a step of forming the conductive film on the resist layer.

[0013] [6] The method for producing a conductive film according to any one of [1] to [4], wherein the conductive film is a conductive film formed on a resist layer of a substrate on which a resist layer is formed.

[0014] [7] The method for producing a conductive film according to any one of [1] to [6], further comprising the following step: A step of determining a wavelength of the laser beam to be irradiated onto the conductive film based on an extinction coefficient k of the conductive film.

[0015] [8] The method for manufacturing a conductive film according to [7], wherein the determining step is a step of determining the wavelength of the laser light using the conductive film irradiated with the laser light in the inspecting step.

[0016] [9] The method for manufacturing a conductive film according to [7], wherein the determining step is a step of determining the wavelength of the laser light using a conductive film separately produced with the same composition as the conductive film irradiated with the laser light in the inspection step.

[0017]

[10] The method for producing a conductive film according to any one of [1] to [9], wherein the wavelength of the laser light is 600 to 1000 nm.

[0018]

[11] The method for producing a conductive film according to

[10] , wherein the wavelength of the laser light is 700 to 900 nm.

[0019]

[12] The method for producing a conductive film according to any one of [1] to

[11] , wherein the conductive film contains a conductive polymer having at least one unit selected from the group consisting of units represented by the following formulae (1) to (4).

[0020] [Chemistry 1]

[0021] [Chemistry 2]

[0022] [Chemistry 3]

[0023] [Chemistry 4]

[0024] In formulas (1) to (4), X represents a sulfur atom or a nitrogen atom, and R 1 ~R 15 Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group or a salt thereof, a hydroxyl group, a nitro group, a halogen atom, -N(R 16 2. -NHCOR 16 、-SR 16 、-OCOR 16 、-COOR 16、-COR 16 , -CHO or -CN. R 16 It represents an alkyl group having 1 to 24 carbon atoms, an aryl group having 6 to 24 carbon atoms, or an aralkyl group having 7 to 24 carbon atoms. Among them, R in formula (1) 1 and R 2 At least one of the formula (2) 3 ~R 6 At least one of the formula (3) 7 ~R 10 At least one of the above and R of formula (4) 11 ~R 15 At least one of them is an acidic group or a salt thereof.

[0025]

[13] The method for producing a conductive film according to any one of [1] to

[11] , wherein the conductive film contains a conductive polymer having a unit represented by the following formula (4).

[0026] [Chemistry 5] In formula (4), R 11 ~R 15 Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group or a salt thereof, a hydroxyl group, a nitro group, a halogen atom, -N(R 16 2. -NHCOR 16 、-SR 16 、-OCOR 16 、-COOR 16 、-COR 16 , -CHO or -CN. R 16 It represents an alkyl group having 1 to 24 carbon atoms, an aryl group having 6 to 24 carbon atoms, or an aralkyl group having 7 to 24 carbon atoms. Among them, R in formula (4) 11 ~R 15 At least one of them is an acidic group or a salt thereof.

[0027]

[14] The method for producing a conductive film according to any one of [1] to

[11] , wherein the conductive film contains at least one selected from a conductive polymer, a basic compound, and a surfactant.

[15] A method for producing a conductive film according to any one of [1] to

[11] , wherein the conductive film comprises at least one selected from a conductive polymer, a basic compound and a surfactant, and the conductive polymer has at least one unit selected from the units represented by the following formulae (1) to (4).

[0028] [Chemistry 6]

[0029] [Chemistry 7]

[0030] [Chemistry 8]

[0031] [Chemistry 9]

[0032] In formulas (1) to (4), X represents a sulfur atom or a nitrogen atom, and R 1 ~R 15 Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group or a salt thereof, a hydroxyl group, a nitro group, a halogen atom, -N(R 16 2. -NHCOR 16 、-SR 16 、-OCOR 16 、-COOR 16 、-COR 16 , -CHO or -CN. R 16 It represents an alkyl group having 1 to 24 carbon atoms, an aryl group having 6 to 24 carbon atoms, or an aralkyl group having 7 to 24 carbon atoms. Among them, R in formula (1) 1 , R 2 At least one of the formula (2) 3 ~R 6 At least one of the formula (3) 7 ~R 10 At least one of the formula (4) 11 ~R 15 At least one of them is an acidic group or a salt thereof.

[0033]

[16] The method for producing a conductive film according to any one of [1] to

[15] , wherein the conductive film has a thickness of 1 to 100 nm.

[0034]

[17] The method for producing a conductive film according to any one of [1] to

[16] , wherein the light intensity of the laser light is 1 mW to 200 W.

[0035]

[18] A method for producing a mask blank with a conductive film, comprising the step of forming the conductive film on a mask blank as a substrate using the method for producing a conductive film according to any one of [1] to

[17] .

[0036]

[19] A method for manufacturing a mask, comprising the following steps: A step of manufacturing a mask blank with a conductive film using the method for manufacturing a mask blank with a conductive film described in

[18] ; A step of manufacturing a mask using the obtained mask blank with a conductive film.

[0037]

[20] A method for manufacturing a mask, comprising the following steps: A process for manufacturing a mask using a mask blank with a conductive film, wherein the mask blank with a conductive film is obtained by the method for manufacturing a mask blank with a conductive film described in

[18] .

[0038]

[21] A method for manufacturing a mask, comprising the following steps: A step of forming the conductive film on a mask blank as a substrate using the conductive film manufacturing method described in any one of [1] to

[17] to manufacture a mask blank with a conductive film; A step of manufacturing a mask using the obtained mask blank with a conductive film.

[0039]

[22] The method for manufacturing a mask according to any one of

[19] to

[21] , further comprising the following step: A step of inspecting defects on the mask blank as a base material by laser irradiation after removing the conductive film from the mask blank with the conductive film.

[0040]

[23] The method for manufacturing a mask according to any one of

[19] to

[21] , further comprising the following step: A step of inspecting defects on the mask blank as a base material after removing the conductive film from the mask blank with the conductive film by laser irradiation.

[0041]

[24] A method for manufacturing a semiconductor device, comprising the following steps: A step of forming the conductive film on the substrate using the conductive film production method described in any one of [3] to [6] to obtain a laminated body; A process of manufacturing a semiconductor device using the laminated body.

[0042]

[25] A method for manufacturing a semiconductor device, comprising the step of manufacturing a semiconductor device using a stacked body having a conductive film obtained by the method for manufacturing a conductive film according to any one of [1] to

[17] .

[0043]

[26] The method for manufacturing a semiconductor device according to

[25] , wherein the conductive film is a conductive film formed on a substrate.

[0044]

[27] The method for manufacturing a semiconductor device according to

[24] or

[26] , further comprising the following step: A step of inspecting defects on the substrate by laser irradiation after removing the conductive film.

[0045]

[28] The method for manufacturing a semiconductor device according to

[24] or

[26] , further comprising the step of inspecting defects on the substrate from which the conductive film is removed by laser irradiation.

[0046]

[29] A method for inspecting defects of a conductive film, comprising irradiating the conductive film with laser light having a wavelength such that the extinction coefficient k of the conductive film is less than or equal to 0.2.

[0047]

[30] A defect inspection device, which takes a conductive film as a measurement object, comprising: An irradiation portion of a laser beam having a wavelength of which the extinction coefficient k of the conductive film is 0.2 or less; An inspection portion for analyzing the presence or absence of defects based on scattered light from the conductive film. Effects of the Invention

[0048] According to the present invention, a method for manufacturing a conductive film, a method for manufacturing a mask, and a method for manufacturing a semiconductor device with high defect detection accuracy can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a schematic cross-sectional view of an example of a laminated body according to an embodiment of the present invention. Figure 2 It is a schematic cross-sectional view of another example of the laminated body according to the embodiment of the present invention. Description of Reference Numerals

[0178] 1.2 Laminated body 11. Substrate 12 Conductive film 13. Resist layer DETAILED DESCRIPTION

[0050] The present invention will be described in detail below. The following embodiments are merely examples for describing the present invention and are not intended to limit the present invention to these embodiments. The present invention can be implemented in various forms without departing from the gist of the present invention.

[0051] It should be noted that, in the present invention, "conductivity" refers to having 1×10 11 Surface resistivity is less than Ω / □. Surface resistivity is the surface resistivity per unit area (1cm 2 The surface resistance value can be obtained by the potential difference between electrodes when a constant current flows. In this specification, "solubility" means that 0.1 g or more of one or more solvents selected from pure water, water containing at least one of a base and a basic salt, water containing an acid, and a mixture of water and a water-soluble organic solvent are uniformly dissolved in 10 g (liquid temperature 25° C.). In addition, "water-soluble" means the solubility relative to water with respect to the above solubility. In the present specification, the "terminal" of the "terminal hydrophobic group" refers to a site other than the repeating unit constituting the polymer. In the present specification, the "mass average molecular weight" refers to the mass average molecular weight (calculated as sodium polystyrene sulfonate or as polyethylene glycol) measured by gel permeation chromatography (GPC). In the present specification, a numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as the lower limit and the upper limit.

[0052] [Method for producing conductive film] One embodiment of the method for producing a conductive film of the present invention will be described.

[0053] The method for producing the conductive film of this embodiment includes the following inspection steps.

[0054] The method for producing a conductive film according to this embodiment may further include the following film forming step. The method for manufacturing a conductive film of this embodiment may further include a substrate preparation step as shown below before the film formation step, and may further include a resist layer formation step as shown below after the substrate preparation step and before the film formation step.

[0055] The method for manufacturing the conductive film of this embodiment may further include the following specific steps.

[0056] <Laminate> In the method for manufacturing a conductive film of this embodiment, the conductive film is, for example, Figure 1 In the laminate 1 shown in FIG. 1 , the conductive film 12 formed on the surface of the substrate 11 or Figure 2 In the illustrated laminated body 2 , a conductive film 12 is formed on the surface of the resist layer 13 on the opposite side to the substrate 11 . Figure 1 The illustrated laminated body 1 is a laminated body including a substrate 11 and a conductive film 12 . The laminated body 1 including the conductive film 12 on the substrate 11 can be prepared by, for example, a substrate preparation step and a film formation step described later. Figure 2The laminated body 2 shown is a laminated body including a substrate 11, a resist layer 13, and a conductive film 12. The resist layer 13 is formed on the substrate 11, and the conductive film 12 is formed on the side of the resist layer 13 opposite to the substrate 11 side. The laminated body 2 including the resist layer 13 and the conductive film 12 on the substrate 11 can be prepared by, for example, a substrate preparing step, a resist layer forming step, and a film forming step to be described later.

[0057] <Substrate preparation step> The substrate preparation step is a step of preparing a substrate serving as a base portion of the conductive film. Examples of the substrate include polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polyolefin resins represented by polyethylene and polypropylene, ethylene chloride, nylon, polystyrene, polycarbonate, epoxy resins, fluororesins, polysulfones, polyimides, polyurethanes, phenolic resins, silicone resins, synthetic paper and other molded products of various polymer compounds, as well as films, paper, iron, glass, quartz glass, various wafers, various mask blanks, aluminum, copper, zinc, nickel, stainless steel and the like, and substrates having various coatings or photosensitive resins coated on the surfaces of these substrates. The shape of the substrate is not particularly limited, and may be a plate shape or a shape other than a plate shape.

[0058] <Resist Layer Formation Step> The resist layer forming step is a step of forming a resist layer on a substrate. In addition, in the present invention, the substrate on which the resist layer is formed is also referred to as a "substrate with a resist layer".

[0059] The resist layer is obtained by applying a resist on a substrate. Examples of the resist include positive-type resists and negative-type resists. The positive resist is not particularly limited as long as it is sensitive to ionizing radiation, and a known resist can be used. Typical examples include the following chemically amplified resists, which contain an acid generator that generates an acid upon irradiation with ionizing radiation and a polymer containing a structural unit having an acid-decomposable group. The negative resist is not particularly limited as long as it is sensitive to ionizing radiation, and a known resist can be used. A typical example is a chemically amplified resist containing an acid generator that generates an acid upon irradiation with ionizing radiation, a polymer soluble in a developer, and a crosslinking agent.

[0060] The resist layer can be formed by a known method, for example, by applying an organic solvent solution of a positive or negative resist on one side of a substrate and heating (prebaking) as necessary to form a positive or negative resist layer. The method for applying the resist is the same as the method for applying the conductive composition described later. The film thickness of the resist layer is not particularly limited, but is, for example, preferably 50 to 200 nm, more preferably 70 to 150 nm.

[0061] <Film Formation Step> The film forming step is a step of forming a conductive film on a substrate or a resist layer before the conductive film inspection step described later, and preparing a conductive film to be inspected in the inspection step. The conductive film is obtained by applying a conductive composition on a substrate or a resist layer and drying the composition. If necessary, the conductive composition may be subjected to a heat treatment after drying. When a resist layer is formed on a substrate, a conductive film is formed on the resist layer of the substrate with the resist layer. When a resist layer is not formed on the substrate, the conductive film is directly formed on the surface of the substrate. The conductive film is preferably a conductive film formed on a substrate or a conductive film formed on a resist layer of a substrate with a resist layer. The thickness of the conductive film is usually 1 to 100 nm, preferably 10 to 80 nm, and more preferably 10 to 60 nm from the viewpoint of accurate pattern formation. The upper limit of the film thickness is preferably 80 nm, more preferably 60 nm, and further preferably 50 nm. The lower limit of the film thickness is preferably 5 nm, more preferably 10 nm, and further preferably 15 nm.

[0062] Examples of the method for coating the conductive composition include spin coating, spray coating, dip coating, roll coating, gravure coating, reverse coating, roll brush coating, air knife coating, and curtain coating. The drying temperature when drying the conductive composition is not particularly limited, but is preferably less than 40° C. The drying time when drying the conductive composition is not particularly limited, but is preferably within 1 hour. From the viewpoint of conductivity, the heat treatment temperature when the conductive composition is dried and then subjected to heat treatment is preferably in the range of 40° C. to 250° C., more preferably in the range of 60° C. to 200° C. From the viewpoint of stability, the heat treatment time is preferably within 1 hour, more preferably within 30 minutes. The thickness of the conductive film is preferably 1 to 100 nm, more preferably 5 to 50 nm, and even more preferably 5 to 30 nm. The conductive composition will be described in detail later.

[0063] <Confirmation of process> The determination step is a step of determining the wavelength of the laser light irradiated onto the conductive film based on the extinction coefficient k of the conductive film. The determination step may be performed before the inspection step described later or after the inspection step. In the determination step, first, the value of the extinction coefficient k of the conductive film at a wavelength of, for example, 200 to 1000 nm is obtained. The extinction coefficient k of the conductive film can be measured using an ellipsometer. The measurement method using an ellipsometer is a method for measuring the optical properties of a measurement object by measuring the change in polarization state when light is reflected from the surface of a material. As specific measurement methods, there are known methods such as a rotating analyzer method in which the polarization state of reflected light is observed by rotating the analyzer, and a phase modulation method in which the polarization state of reflected light is observed by the action of a photoelastic modulator.

[0064] Next, the wavelength when the extinction coefficient k of the conductive film is 0.2 or less is confirmed, and the wavelength of the laser light is determined so that the wavelength when the extinction coefficient k is 0.2 or less is the same as the wavelength of the laser light used in the inspection step described later.

[0065] It should be noted that, in the determination process, the extinction coefficient k may be measured using the conductive film actually irradiated with laser light in the inspection process described later, thereby determining the wavelength of the laser light irradiated to the conductive film. In addition, a conductive film may be separately produced in a manner having the same composition as the conductive film included in the conductive film actually irradiated with laser light in the inspection process, and the extinction coefficient k may be measured using the separately produced conductive film, thereby determining the wavelength of the laser light irradiated to the conductive film. The thickness of the conductive film when the separately produced conductive film is produced is, for example, 30 nm.

[0066] <Inspection process> The inspection step is a step of irradiating the conductive film with laser light to inspect defects of the conductive film. The inspection step can be performed on any or all conductive films. Hereinafter, this step is also referred to as a "first inspection step." In the present invention, "defects of the conductive film" refers to, for example, defects generated when the conductive film is formed on a substrate or on a resist layer. In addition, "defects on the substrate" described below refers to defects from the substrate, defects generated when a resist layer is formed on the substrate, defects generated when a conductive film is formed on the resist layer, defects generated when the conductive film is removed from the resist layer, defects generated when the resist layer is removed from the substrate, etc. In addition, the "defect" refers to an adhering matter, a protrusion, a scratch, etc. attached to a base material, a resist layer, or a conductive film.

[0067] In the inspection process, the conductive film is irradiated with laser light having a wavelength at which the extinction coefficient k of the conductive film is 0.2 or less. That is, the extinction coefficient k of the conductive film at the wavelength of the laser light irradiated with the conductive film is 0.2 or less. If a laser with a wavelength whose extinction coefficient k is less than 0.2 is irradiated onto a conductive film, the conductive film is unlikely to absorb the laser. Therefore, when there is a defect in the conductive film, the laser irradiated onto the defect is easily scattered, making it easy to detect the defect in the conductive film.

[0068] The wavelength of the laser is not particularly limited as long as it is a wavelength when the extinction coefficient k of the conductive film is less than 0.2. It is preferably a wavelength when the extinction coefficient k is less than 0.17, more preferably a wavelength when it is less than 0.15, further preferably a wavelength when it is less than 0.10, and further preferably a wavelength when it is less than 0.05. In addition, the wavelength of the laser is preferably a wavelength when the extinction coefficient k of the conductive film is 0 to 0.2, preferably a wavelength when 0.001 to 0.2, more preferably a wavelength when 0.001 to 0.17, further preferably a wavelength when 0.001 to 0.15, further preferably a wavelength when 0.001 to 0.10, and particularly preferably a wavelength when 0.001 to 0.05. In particular, from the viewpoint of suppressing absorption of the irradiated light by the conductive film, the wavelength of the laser light is preferably 600 to 1000 nm, more preferably 700 to 900 nm. From the viewpoint of improving inspection accuracy, the optical intensity of the laser light is preferably 1 mW to 200 W, more preferably 1 mW to 100 W, further preferably 1 mW to 10 W, and particularly preferably 1 mW to 1 W.

[0069] Examples of lasers used to irradiate the conductive film include semiconductor lasers (266 nm, 355 nm, 532 nm), excimer lasers (193 nm, 248 nm), argon lasers (488 nm), green lasers (520 nm), red lasers (660 nm), He-Ne lasers (633 nm), ruby ​​lasers (694 nm), and near-infrared fiber lasers (785 nm).

[0070] One embodiment of the present invention is a defect inspection method of a conductive film, comprising irradiating the conductive film with laser light having a wavelength at which the extinction coefficient k of the conductive film is 0.2 or less. Another embodiment of the present invention is a defect inspection device that takes a conductive film as a measurement object and comprises: an irradiation unit that irradiates a laser beam having a wavelength whose extinction coefficient k of the conductive film is 0.2 or less; and an inspection unit that analyzes the presence or absence of defects based on scattered light from the conductive film. As the analysis unit of the inspection section, a known unit can be used.

[0071] Defects of the conductive film are specifically detected as follows. First, the conductive film is irradiated with laser light having a specific wavelength. When there is a defect in the conductive film, the laser light irradiated to the defect is scattered, and the scattered laser light is detected by the detector, thereby detecting the defect in the conductive film.

[0072] <Conductive Composition> The conductive composition is a composition containing a conductive polymer (A) and a solvent (D) as shown below. In the conductive composition, in addition to the conductive polymer (A) and the solvent (D), it may further contain at least one selected from the alkaline compound (B) and the surfactant (C) as shown below. In addition, the conductive composition may further contain a component (arbitrary component) other than the conductive polymer (A), the solvent (D), and at least one of the alkaline compound (B) and the surfactant (C). That is, the conductive film is a film containing a conductive polymer (A). In the conductive film, in addition to the conductive polymer (A), it may further contain at least one selected from the alkaline compound (B) and the surfactant (C), and in addition to the conductive polymer (A) and at least one selected from the alkaline compound (B) and the surfactant (C), it may further contain an arbitrary component.

[0073] (Conductive polymer (A)) As the conductive polymer (A), known polymers can be used, for example, polythiophene, polythienylene vinylene, poly(3-alkylthiophene), poly(3,4-ethylenedioxy)thiophene (PEDOT), poly-3,4-ethylenedioxythiophene-polystyrenesulfonic acid (PEDOT-PSS), polyaniline, polypyrrole, polytellurophene, polyparaphenylene, polyparaphenylene vinylene, polyacene and polyacetylene.

[0074] The conductive polymer (A) is preferably water-soluble or water-dispersible. When the conductive polymer (A) is water-soluble or water-dispersible, the coating properties of the conductive composition are improved, and a conductive film having a uniform thickness can be easily obtained. The conductive polymer (A) preferably has an acidic group or a salt thereof. When the conductive polymer (A) has an acidic group or a salt thereof, the water solubility of the conductive polymer (A) is improved. The conductive polymer (A) may have two types of acidic groups in one molecule, and a part or all of the acidic groups may form a salt.

[0075] As the conductive polymer (A) having an acidic group or a salt thereof, from the viewpoint of solubility, for example, Japanese Patent Application Laid-Open No. 61-197633, Japanese Patent Application Laid-Open No. 63-39916, Japanese Patent Application Laid-Open No. 1-301714, Japanese Patent Application Laid-Open No. 5-504153, Japanese Patent Application Laid-Open No. 5-503953, Japanese Patent Application Laid-Open No. 4-32848, Japanese Patent Application Laid-Open No. 4-328181, Japanese Patent Application Laid-Open No. 6-145386, Japanese Patent Application Laid-Open No. 6-56987, Japanese Patent Application Laid-Open No. 4-58647, Japanese Patent Application Laid-Open No. 4-58650, Japanese Patent Application Laid-Open No. 4-58661, Japanese Patent Application Laid-Open No. 4-58673, Japanese Patent Application Laid-Open No. 4-586647, Japanese Patent Application Laid-Open No. 4-58665 Conductive polymers disclosed in Japanese Patent Application Laid-Open No. 5-226238, Japanese Patent Application Laid-Open No. 5-178989, Japanese Patent Application Laid-Open No. 6-293828, Japanese Patent Application Laid-Open No. 7-118524, Japanese Patent Application Laid-Open No. 6-32845, Japanese Patent Application Laid-Open No. 6-87949, Japanese Patent Application Laid-Open No. 6-256516, Japanese Patent Application Laid-Open No. 7-41756, Japanese Patent Application Laid-Open No. 7-48436, Japanese Patent Application Laid-Open No. 4-268331, or Japanese Patent Application Laid-Open No. 2014-65898.

[0076] As the conductive polymer (A), specifically, there can be mentioned: a π-conjugated conductive polymer in which the α-position or β-position is substituted with at least one group selected from a sulfonic acid group and a carboxyl group, and the π-conjugated conductive polymer contains at least one selected from a phenylene vinylene group, a vinylene group, a thiophenylene group, a pyrrolyl group, a phenylene group, an aminophenylene group, an isothianaphthene group, a furanyl group and a carbazolylene group as a repeating unit. In addition, when the π-conjugated conductive polymer contains at least one repeating unit selected from an aminophenylene group and a carbazolylene group, examples include: a conductive polymer having an acidic group or a salt thereof on the nitrogen atom of the repeating unit, or a conductive polymer having an alkyl group or an ether-bonded alkyl group substituted with an acidic group or a salt thereof on the nitrogen atom. Among these, from the viewpoint of conductivity and solubility, it is preferred to use a conductive polymer having as a monomer unit (unit) at least one selected from thienylene, pyrrolylene, aminophenylene, phenylene vinylene, carbazolylene and isothianaphthene groups substituted at the β-position with an acidic group or a salt thereof.

[0077] As the conductive polymer (A), among the above, at least one selected from polyaniline having an acidic group or a salt thereof, PEDOT, PEDOT-PSS, polypyrrole and polythiophene is preferred from the viewpoint of excellent conductivity. Among them, polyaniline having an acidic group or a salt thereof is a compound having excellent solubility in water and is therefore particularly suitable as a conductive polymer.

[0078] Examples of polyanilines having an acidic group or a salt thereof include polymers having a skeleton in a π-conjugated polymer such as unsubstituted or substituted polyaniline or polydiaminoanthraquinone, or having an acidic group or a salt thereof on a nitrogen atom in the π-conjugated polymer. Among these, a conductive polymer having at least one unit selected from the units represented by the following formulae (1) to (4) is preferred from the viewpoint of being able to exhibit high conductivity and solubility, and a conductive polymer containing 20 to 100 mol % of the unit in all units (100 mol %) constituting the conductive polymer is more preferred.

[0079] [Chemistry 10]

[0080] [Chemistry 11]

[0081] [Chemistry 12]

[0082] [Chemistry 13]

[0083] In formulas (1) to (4), X represents a sulfur atom or a nitrogen atom, and R 1 ~R 15 Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group or a salt thereof, a hydroxyl group, a nitro group, a halogen atom (-F, -Cl, -Br or -I), -N(R 16 2. -NHCOR 16 、-SR 16 、-OCOR 16 、-COOR 16 、-COR 16 , -CHO or -CN. R 16 It represents an alkyl group having 1 to 24 carbon atoms, an aryl group having 6 to 24 carbon atoms, or an aralkyl group having 7 to 24 carbon atoms. Among them, R in formula (1) 1 and R 2 At least one of the formula (2) 3 ~R 6 At least one of the formula (3) 7 ~R 10 At least one of the above and R of formula (4) 11 ~R 15 At least one of them is an acidic group or a salt thereof.

[0084] Here, the "acidic group" refers to a sulfonic acid group (sulfo group) or a carboxylic acid group (carboxyl group). The sulfonic acid group may be present in the acid state (-SO3H) or in the ionic state (-SO3 - ) contains a sulfonic acid group. Furthermore, the sulfonic acid group also contains a substituent having a sulfonic acid group (-R 17 SO3H). On the other hand, the carboxylic acid group may be contained in the acid state (-COOH) or in the ionic state (-COO - ) contains a carboxylic acid group. Further, the carboxylic acid group also contains a substituent having a carboxylic acid group (-R 17 COOH). The above R 17 It represents a linear or branched alkylene group having 1 to 24 carbon atoms, a linear or branched arylene group having 6 to 24 carbon atoms, or a linear or branched aralkylene group having 7 to 24 carbon atoms. As the acidic group, a sulfonic acid group is preferred.

[0085] Examples of the salt of the acidic group include alkali metal salts, alkaline earth metal salts, ammonium salts, and substituted ammonium salts of a sulfonic acid group or a carboxylic acid group.

[0086] Examples of the alkali metal salt include lithium sulfate, lithium carbonate, lithium hydroxide, sodium sulfate, sodium carbonate, sodium hydroxide, potassium sulfate, potassium carbonate, potassium hydroxide, and derivatives having these skeletons.

[0087] Examples of the alkaline earth metal salt include magnesium salt and calcium salt.

[0088] As a substituted ammonium salt, an aliphatic ammonium salt, a saturated alicyclic ammonium salt, an unsaturated alicyclic ammonium salt, etc. are mentioned, for example.

[0089] Examples of the aliphatic ammonium salt include methylammonium, dimethylammonium, trimethylammonium, ethylammonium, diethylammonium, triethylammonium, methylethylammonium, diethylmethylammonium, dimethylethylammonium, propylammonium, dipropylammonium, isopropylammonium, diisopropylammonium, butylammonium, dibutylammonium, methylpropylammonium, ethylpropylammonium, methylisopropylammonium, ethylisopropylammonium, methylbutylammonium, ethylbutylammonium, tetramethylammonium, tetrahydroxymethylammonium, tetraethylammonium, tetra-n-butylammonium, tetra-sec-butylammonium, and tetra-tert-butylammonium.

[0090] Examples of the saturated alicyclic ammonium salt include piperidinium, pyrrolidinium, morpholinium, piperazinium, and derivatives having these skeletons. Examples of the unsaturated alicyclic ammonium salt include pyridinium, α-methylpyridinium, β-methylpyridinium, γ-methylpyridinium, quinolinium, isoquinolinium, pyrrolinium, and derivatives having these skeletons.

[0091] The conductive polymer (A) preferably has a unit represented by the above formula (4) from the viewpoint of exhibiting high conductivity, and more preferably has a unit represented by the following formula (5) from the viewpoint of excellent solubility.

[0092] [Chemistry 14]

[0093] In formula (5), R 18 ~R 21 Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group or a salt thereof, a hydroxyl group, a nitro group or a halogen atom (-F, -Cl, -Br or -I). 18 ~R 21 At least one of them is an acidic group or a salt thereof.

[0094] As the unit represented by the above formula (5), the following unit is preferred from the viewpoint of easy production: R 18 ~R 21 Among them, any one is a linear or branched alkoxy group having 1 to 4 carbon atoms, any other one is a sulfonic acid group or a salt thereof, and the rest are hydrogen atoms.

[0095] From the viewpoint of having excellent solubility in water and organic solvents regardless of pH, the conductive polymer (A) preferably contains 10 to 100 mol%, more preferably 50 to 100 mol%, and particularly preferably 100 mol% of the unit represented by the above formula (5) in all the units (100 mol%) constituting the conductive polymer (A). In addition, from the viewpoint of excellent conductivity, the conductive polymer (A) preferably contains 10 or more units represented by the above formula (5) in one molecule.

[0096] In addition, in the conductive polymer (A), from the viewpoint of further improving solubility, the number of aromatic rings to which the acidic group or its salt is bonded is preferably 50% or more, more preferably 70% or more, further preferably 80% or more, particularly preferably 90% or more, and most preferably 100% relative to the total number of aromatic rings in the polymer. The number of aromatic rings to which the acidic group or its salt is bonded relative to the total number of aromatic rings in the polymer is a value calculated from the charging ratio of the monomers when producing the conductive polymer (A).

[0097] In addition, in the conductive polymer (A), from the viewpoint of imparting reactivity to the monomer, the substituent other than the acidic group or its salt on the aromatic ring of the monomer unit is preferably an electron donating group, specifically, preferably an alkyl group having 1 to 24 carbon atoms, an alkoxy group having 1 to 24 carbon atoms, a halogen group (-F, -Cl, -Br or -I), etc., among which, from the viewpoint of electron donating property, an alkoxy group having 1 to 24 carbon atoms is most preferred.

[0098] Furthermore, the conductive polymer (A) may contain, as a structural unit other than the unit represented by the above formula (5), one or more units selected from the group consisting of substituted or unsubstituted aniline, thiophene, pyrrole, phenylene, vinylene, divalent unsaturated groups and divalent saturated groups, as long as the solubility, conductivity and properties are not affected.

[0099] As the conductive polymer (A), from the viewpoint of being able to exhibit high conductivity and solubility, a compound having a structure represented by the following formula (6) is preferred. Among the compounds having a structure represented by the following formula (6), poly(2-sulfo-5-methoxy-1,4-imidophenylene) and poly(2-methoxyaniline-5-sulfonic acid) are particularly preferred from the viewpoint of being particularly excellent in solubility.

[0100] [Chemistry 15]

[0101] In formula (6), R 22 ~R 37 Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, a linear or branched alkoxy group having 1 to 4 carbon atoms, an acidic group or a salt thereof, a hydroxyl group, a nitro group or a halogen atom (-F, -Cl, -Br or -I). 22 ~R 37 At least one of them is an acidic group or a salt thereof. In addition, n represents a degree of polymerization. In the present invention, n is preferably an integer of 5 to 2500.

[0102] As the unit represented by the above formula (6), the following unit is preferred from the viewpoint of easy production: R 22 ~R 25 Among them, any one is a linear or branched alkoxy group having 1 to 4 carbon atoms, any other one is a sulfonic acid group or a salt thereof, and the rest are hydrogen atoms; R 26 ~R 29 Among them, any one is a linear or branched alkoxy group having 1 to 4 carbon atoms, any other one is a sulfonic acid group or a salt thereof, and the rest are hydrogen atoms; R 30 ~R 33Among them, any one is a linear or branched alkoxy group having 1 to 4 carbon atoms, any other one is a sulfonic acid group or a salt thereof, and the rest are hydrogen atoms; R 34 ~R 37 Among them, any one is a linear or branched alkoxy group having 1 to 4 carbon atoms, any other one is a sulfonic acid group or a salt thereof, and the rest are hydrogen atoms.

[0103] From the viewpoint of improving conductivity, it is desirable that at least a part of the acidic groups contained in the conductive polymer (A) be in the free acid form.

[0104] From the viewpoint of conductivity, solubility and film-forming property, the mass average molecular weight of the conductive polymer (A) is preferably 1,000 to 1,000,000, more preferably 1,500 to 800,000, further preferably 2,000 to 500,000, and particularly preferably 2,000 to 100,000, based on sodium polystyrene sulfonate measured by GPC. When the mass average molecular weight of the conductive polymer (A) is less than 1,000, although the solubility is excellent, there is a case where the conductivity and film-forming property are insufficient. On the other hand, when the mass average molecular weight is greater than 1,000,000, although the conductivity is excellent, there is a case where the solubility is insufficient. Here, "film-forming property" refers to the property of forming a uniform film without pinholes, and can be evaluated by a method such as spin coating on glass.

[0105] The conductive polymer (A) can be obtained, for example, by polymerizing a raw material monomer of the conductive polymer (A) in the presence of a polymerization solvent and an oxidizing agent. Next, an example of a method for producing the conductive polymer (A) is described. The method for producing the conductive polymer (A) of the present embodiment includes: a step of polymerizing the raw material monomer of the conductive polymer (A) in the presence of a polymerization solvent and an oxidant (polymerization step). In addition, the method for producing the conductive polymer (A) of the present embodiment may further include: a step of purifying the reaction product obtained in the polymerization step (purification step).

[0106] <<Polymerization process>> The polymerization step is a step of polymerizing the raw material monomers of the conductive polymer (A) in the presence of a polymerization solvent and an oxidizing agent. Specific examples of the raw material monomer include polymerizable monomers derived from the above-mentioned monomer units, specifically at least one selected from the group consisting of acidic group-substituted aniline, alkali metal salts, alkaline earth metal salts, ammonium salts and substituted ammonium salts of acidic group-substituted aniline. Examples of the acidic group-substituted aniline include sulfonic acid group-substituted aniline having a sulfonic acid group as the acidic group. Representative examples of sulfonic acid group-substituted anilines include aminobenzenesulfonic acids, and specifically, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, aniline-2,6-disulfonic acid, aniline-2,5-disulfonic acid, aniline-3,5-disulfonic acid, aniline-2,4-disulfonic acid, and aniline-3,4-disulfonic acid are preferably used.

[0107] As sulfonic acid group-substituted anilines other than aminobenzenesulfonic acids, for example, there can be mentioned: alkyl-substituted aminobenzenesulfonic acids such as methylaminobenzenesulfonic acid, ethylaminobenzenesulfonic acid, n-propylaminobenzenesulfonic acid, isopropylaminobenzenesulfonic acid, n-butylaminobenzenesulfonic acid, sec-butylaminobenzenesulfonic acid, and tert-butylaminobenzenesulfonic acid; alkoxy-substituted aminobenzenesulfonic acids such as methoxyaminobenzenesulfonic acid, ethoxyaminobenzenesulfonic acid, and propoxyaminobenzenesulfonic acid; hydroxy-substituted aminobenzenesulfonic acids; nitro-substituted aminobenzenesulfonic acids; halogen-substituted aminobenzenesulfonic acids such as fluoroaminobenzenesulfonic acid, chloroaminobenzenesulfonic acid, and bromoaminobenzenesulfonic acid; and the like. Among these, alkyl-substituted aminobenzenesulfonic acids, alkoxy-substituted aminobenzenesulfonic acids, hydroxy-substituted aminobenzenesulfonic acids or halogen-substituted aminobenzenesulfonic acids are preferred from the perspective of obtaining a conductive polymer (A) having particularly excellent conductivity and solubility. Alkoxy-substituted aminobenzenesulfonic acids and alkali metal salts, ammonium salts and substituted ammonium salts of alkoxy-substituted aminobenzenesulfonic acids are particularly preferred from the perspective of easy production. These sulfonic acid group-substituted anilines may be used alone or in combination of two or more in any ratio.

[0108] Examples of the polymerization solvent include water, organic solvents, and mixed solvents of water and organic solvents. Examples of water include tap water, ion-exchanged water, pure water, and distilled water. Examples of the organic solvent include alcohols such as methanol, ethanol, isopropanol, propanol, and butanol; ketones such as acetone and ethyl isobutyl ketone; ethylene glycols such as ethylene glycol and ethylene glycol methyl ether; propylene glycols such as propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, and propylene glycol propyl ether; amides such as N,N-dimethylformamide and N,N-dimethylacetamide; pyrrolidones such as N-methylpyrrolidone and N-ethylpyrrolidone, and the like. As the polymerization solvent, water or a mixed solvent of water and an organic solvent is preferred. When a mixed solvent of water and an organic solvent is used as the polymerization solvent, the mass ratio of these (water / organic solvent) is preferably 1 / 100 to 100 / 1, and more preferably 2 / 100 to 100 / 2.

[0109] The oxidant is not limited as long as it has a standard electrode potential of 0.6 V or more, and examples thereof include peroxodisulfuric acids such as peroxodisulfuric acid, ammonium peroxodisulfate, sodium peroxodisulfate, and potassium peroxodisulfate; and hydrogen peroxide. These oxidizing agents may be used alone or in combination of two or more in any ratio.

[0110] In the polymerization step, the raw material monomers may be polymerized in the presence of a basic reaction aid in addition to the polymerization solvent and the oxidant. Examples of the alkaline reaction auxiliary agent include inorganic bases such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; ammonia; aliphatic amines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylmethylamine, ethyldimethylamine, and diethylmethylamine; cyclic saturated amines; cyclic unsaturated amines such as pyridine, α-picoline, β-picoline, γ-picoline, and quinoline; and the like. Among these, inorganic bases, aliphatic amines, and cyclic unsaturated amines are preferred, and cyclic unsaturated amines are more preferred. These alkaline reaction aids may be used alone or in combination of two or more in any ratio.

[0111] Examples of the polymerization method include: a method of dropping a raw monomer solution into an oxidant solution, a method of dropping an oxidant solution into a raw monomer solution, a method of simultaneously dropping a raw monomer solution and an oxidant solution into a reaction vessel, etc. The raw monomer solution may further contain a basic reaction aid as required. As the solvent for the oxidizing agent solution and the raw material monomer solution, the above-mentioned polymerization solvent can be used.

[0112] The reaction temperature of the polymerization reaction is preferably 50°C or less, more preferably -15 to 30°C, and further preferably -10 to 20°C. If the reaction temperature of the polymerization reaction is 50°C or less, particularly 30°C or less, the conduction of side reactions or the decrease in conductivity caused by the change in the redox structure of the main chain of the generated conductive polymer (A) can be suppressed. If the reaction temperature of the polymerization reaction is -15°C or more, a sufficient reaction rate can be maintained and the reaction time can be shortened.

[0113] Through the polymerization step, the conductive polymer (A) as a reaction product is obtained in a state of being dissolved or precipitated in the polymerization solvent. When the reaction product is dissolved in the polymerization solvent, the polymerization solvent is distilled off to obtain the reaction product. When the reaction product is precipitated in the polymerization solvent, the polymerization solvent is filtered out using a filter such as a centrifugal separator to obtain the reaction product.

[0114] The reaction product may contain low molecular weight components such as unreacted raw material monomers, oligomers generated by side reactions, acidic substances (free acidic groups separated from the conductive polymer (A), sulfate ions as oxidant decomposition products, etc.), and alkaline substances (alkaline reaction aids, ammonium ions as oxidant decomposition products, etc.). These low molecular weight components are impurities and are the main cause of hindering conductivity. Therefore, it is preferred to purify the reaction product to remove low molecular weight components.

[0115] <<Purification process>> The purification step is a step of purifying the reaction product obtained in the polymerization step. As a method for purifying the reaction product, the following methods can be used: a washing method using a washing solvent, a membrane filtration method, an ion exchange method, all methods such as removing impurities by heat treatment, neutralization and precipitation. Among these, from the viewpoint that a highly pure conductive polymer (A) can be easily obtained, a washing method and an ion exchange method are very effective. In particular, based on the viewpoint that raw material monomers, oligomers, acidic substances, etc. can be effectively removed, a washing method is preferably used. Based on the viewpoint that alkaline substances that exist in a state of forming salts with the acidic groups of the conductive polymer (A) can be effectively removed, an ion exchange method is preferably used. In the purification process, a washing method and an ion exchange method can also be used in combination.

[0116] Examples of the washing solvent include alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-butanol, 3-butanol, tert-butanol, 1-pentanol, 3-methyl-1-butanol, 2-pentanol, n-hexanol, 4-methyl-2-pentanol, 2-ethylbutanol, benzyl alcohol, furfuryl alcohol, and tetrahydrofurfuryl alcohol; polyol derivatives such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methoxymethoxyethanol, propylene glycol monoethyl ether, and glycerol monoacetate; acetone; acetonitrile; N,N-dimethylformamide; N-methylpyrrolidone; and dimethyl sulfoxide. Among these, methanol, ethanol, isopropanol, acetone, and acetonitrile are particularly effective.

[0117] When the reaction product after washing, that is, the washed conductive polymer (A) is dried, a solid conductive polymer (A) can be obtained.

[0118] Examples of the ion exchange method include column and batch treatments using ion exchange resins such as cation exchange resins and anion exchange resins, and electrodialysis. When the reaction product is dissolved in the polymerization solvent, it may be directly contacted with the ion exchange resin in a dissolved state. When the concentration of the reaction product is high, it may be diluted with an aqueous medium. When the reaction product precipitates in the polymerization solvent, it is preferred that the polymerization solvent is filtered off and then the reaction product is dissolved in an aqueous medium to a desired solid content concentration to form a polymer solution, which is then contacted with the ion exchange resin. When the washed reaction product is subjected to ion exchange treatment, it is preferred that the washed reaction product is dissolved in an aqueous medium to a desired solid content concentration to form a polymer solution, and then contacted with an ion exchange resin. Examples of the aqueous medium include the same solvents as the solvent (D) described below. The concentration of the conductive polymer (A) in the polymer solution is preferably 0.1 to 20% by mass, more preferably 0.1 to 10% by mass, from the viewpoint of industrial efficiency and purification efficiency.

[0119] In the case of an ion exchange method using an ion exchange resin, the amount of the sample solution relative to the ion exchange resin is preferably 10 times the volume, and more preferably 5 times the volume, relative to the ion exchange resin, when it is a polymer solution with a solid content concentration of 5% by mass. Examples of cation exchange resins include "Amberlite IR-120B" manufactured by Organo Co., Ltd. and the like. Examples of anion exchange resins include "Amberlite IRA410" manufactured by Organo Co., Ltd. and the like.

[0120] The conductive polymer (A) after the ion exchange treatment is in a state of being dissolved in the polymerization solvent or the aqueous medium. Therefore, if the polymerization solvent or the aqueous medium is completely removed by an evaporator or the like, a solid conductive polymer (A) can be obtained, but the conductive polymer (A) can also be directly used in the production of a conductive composition in a state of being dissolved in the polymerization solvent or the aqueous medium.

[0121] (Basic compound (B)) In the case where the conductive polymer (A) has an acidic group, it is believed that if the conductive composition contains a basic compound (B), the basic compound (B) can effectively act on the acidic group in the conductive polymer (A), which can improve the stability of the conductive polymer (A). Here, the acidic group that acts efficiently on the conductive polymer (A) means that the conductive polymer (A) can be stably neutralized, and the acidic group of the conductive polymer (A) is used to form a stable salt with the basic compound (B). That is, the conductive polymer (A) is neutralized by the basic compound (B). As a result, the destabilization of the acidic group of the conductive polymer (A) caused by hydrolysis in the conductive composition can be suppressed, and the acidic group is difficult to detach. Moreover, by using the acidic group of the conductive polymer (A) to form a stable salt with the basic compound (B), the decomposition of the conductive polymer (A) itself can also be suppressed. In addition, the basic compound (B) also forms a stable salt with the decomposition product (such as sulfate ions, etc.) of the oxidant used in the manufacture of the conductive polymer (A). Therefore, the generation of acidic groups derived from the conductive polymer (A) and sulfate ions derived from the oxidizing agent in the conductive composition can be suppressed. In addition, the content of decomposition products of the conductive polymer (A) in the conductive composition can also be reduced. Therefore, in particular, in a patterning method using ionizing radiation using a chemically amplified resist, migration of acidic substances and the like from the conductive film to the resist layer side can be suppressed, and the influence of film loss of the resist layer and the like can be suppressed.

[0122] Examples of the basic compound (B) include any compound having basicity, and are not particularly limited, and examples thereof include the following quaternary ammonium compounds (b-1), basic compounds (b-2), basic compounds (b-3), and basic compounds (b-4). Quaternary ammonium compound (b-1): a quaternary ammonium compound in which at least one of the four substituents bonded to the nitrogen atom is a hydrocarbon group having 1 or more carbon atoms. Basic compound (b-2): a basic compound having one or more nitrogen atoms (excluding the quaternary ammonium compound (b-1) and the basic compound (b-3)). Basic compound (b-3): a basic compound having a basic group and two or more hydroxyl groups in the same molecule and having a melting point of 30° C. or higher. Basic compound (b-4): Inorganic base.

[0123] In the quaternary ammonium compound (b-1), the nitrogen atom to which the four substituents are bonded is the nitrogen atom of the quaternary ammonium ion. In the quaternary ammonium compound (b-1), examples of the hydrocarbon group bonded to the nitrogen atom of the quaternary ammonium ion include an alkyl group, an aralkyl group, and an aryl group. Examples of the quaternary ammonium compound (b-1) include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, tetrahexylammonium hydroxide, and benzyltrimethylammonium hydroxide.

[0124] Examples of the basic compound (b-2) include ammonia, pyridine, 4-dimethylaminopyridine, 4-dimethylaminomethylpyridine, 3,4-bis(dimethylamino)pyridine, methylpyridine, triethylamine, 4-dimethylaminopyridine, 4-dimethylaminomethylpyridine, 3,4-bis(dimethylamino)pyridine, 1,5-diazabicyclo[4.3.0]-5-nonene (DBN), 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 1-(3-aminopropyl)-2-pyrrolidone, N-(3-aminopropyl)-ε-caprolactam, and derivatives thereof.

[0125] In the basic compound (b-3), as a basic group, for example, a basic group defined by an Arrhenius base, a Bronsted base, a Lewis base, etc. Specifically, ammonia, etc. The hydroxyl group may be in the state of -OH, or in the state protected by a protecting group. As a protecting group, for example, an acetyl group; a silyl group such as a trimethylsilyl group and a tert-butyldimethylsilyl group; an acetal type protecting group such as a methoxymethyl group, an ethoxymethyl group, a methoxyethoxymethyl group; a benzoyl group; an alcoholoxy group, etc. Examples of the basic compound (b-3) include 2-amino-1,3-propanediol, tris(hydroxymethyl)aminomethane, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propanediol, 3-[N-tris(hydroxymethyl)methylamino]-2-hydroxypropanesulfonic acid, and N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid.

[0126] Examples of the basic compound (b-4) include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like. These basic compounds (B) may be used alone or in combination of two or more in any ratio.

[0127] (Surfactant (C)) When the conductive composition contains the surfactant (C), coating properties are improved when the conductive composition is applied to the surface of a substrate or a resist layer. Examples of the surfactant (C) include anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc. These surfactants may be used alone or in combination of two or more in any ratio.

[0128] Examples of the anionic surfactant include sodium dialkyl sulfosuccinate, sodium caprylate, sodium caprate, sodium laurate, sodium myristate, sodium palmitate, sodium stearate, perfluorononanoic acid, sodium N-lauroyl sarcosinate, sodium cocoyl glutamate, α-sulfo fatty acid methyl ester salt, sodium lauryl sulfate, sodium myristyl sulfate, sodium laureth sulfate, sodium polyoxyethylene alkylphenol sulfonate, ammonium lauryl sulfate, lauryl phosphoric acid, sodium lauryl phosphate, potassium lauryl phosphate, and the like.

[0129] Examples of the cationic surfactant include tetramethylammonium chloride, tetramethylammonium hydroxide, tetrabutylammonium chloride, dodecyldimethylbenzylammonium chloride, alkyltrimethylammonium chloride, octyltrimethylammonium chloride, decyltrimethylammonium chloride, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, benzyltrimethylammonium chloride, alkyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzalkonium chloride, benzalkonium bromide, benzethonium chloride, dialkyldimethylammonium chloride, didecyldimethylammonium chloride, distearyldimethylammonium chloride, monomethylamine hydrochloride, dimethylamine hydrochloride, trimethylamine hydrochloride, butylpyridinium chloride, dodecylpyridinium chloride, and hexadecylpyridinium chloride.

[0130] Examples of the amphoteric surfactant include lauryl dimethylaminoacetic acid betaine, stearyl dimethylaminoacetic acid betaine, dodecylaminomethyl dimethyl sulfopropyl betaine, octadecylaminomethyl dimethyl sulfopropyl betaine, cocamidopropyl betaine, cocamidopropyl hydroxysulfopropyl betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, sodium lauroyl glutamate, potassium lauroyl glutamate, lauroyl methyl-β-alanine, lauryl dimethylamine-N-oxide, and oleyl dimethylamine N-oxide.

[0131] Examples of the nonionic surfactant include glyceryl laurate, glyceryl monostearate, sorbitan fatty acid esters, sucrose fatty acid esters, polyoxyethylene alkyl ethers, pentaethylene glycol monododecyl ether, octaethylene glycol monododecyl ether, polyoxyethylene alkylphenyl ethers, octylphenol ethoxylates, nonylphenol ethoxylates, polyoxyethylene polyoxypropylene glycol, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene hexitan fatty acid esters, sorbitan fatty acid ester polyethylene glycol, lauric acid diethanolamide, oleic acid diethanolamide, stearic acid diethanolamide, octyl glucoside, decyl glucoside, lauryl glucoside, cetyl alcohol, stearyl alcohol, and oleyl alcohol.

[0132] As a nonionic surfactant, in addition to the above, a water-soluble polymer having a nitrogen-containing functional group and a terminal hydrophobic group can also be used. This water-soluble polymer is different from the existing surfactant, and has a main chain part (hydrophilic part) having a nitrogen-containing functional group and a terminal hydrophobic group part, and has a surface active ability, and the effect of improving the coating property is high. Therefore, even if other surfactants are not used in combination, it is possible to give excellent coating properties to the conductive composition. Moreover, the water-soluble polymer does not contain acid and alkali, and it is difficult to produce by-products due to hydrolysis, so for example, the adverse effects on the resist layer are particularly few.

[0133] As the nitrogen-containing functional group, an amide group is preferred from the viewpoint of solubility. Examples of the terminal hydrophobic group include alkyl, aralkyl, aryl, alkoxy, aralkyloxy, aryloxy, alkylthio, aralkylthio, arylthio, primary or secondary alkylamino, aralkylamino, and arylamino, among which alkylthio, aralkylthio, and arylthio are preferred. The number of carbon atoms in the terminal hydrophobic group is preferably 7 to 100, more preferably 7 to 50, particularly preferably 10 to 30. The number of terminal hydrophobic groups in the water-soluble polymer is not particularly limited. In addition, when there are two or more terminal hydrophobic groups in the same molecule, the terminal hydrophobic groups may be of the same type or of different types.

[0134] As water-soluble polymers, the following compounds are preferred: compounds having a homopolymer of a vinyl monomer having a nitrogen-containing functional group, or a copolymer of a vinyl monomer having a nitrogen-containing functional group and a vinyl monomer not having a nitrogen-containing functional group (other vinyl monomers) as the main chain structure, and having a hydrophobic group at a position other than the repeating units constituting the polymer. As the vinyl monomer having a nitrogen-containing functional group, there can be mentioned: acrylamide and its derivatives, heterocyclic monomers having a nitrogen-containing functional group, etc., among which preferably have an amide bond. Specifically, there can be mentioned: acrylamide, N,N-dimethylacrylamide, N-isopropylacrylamide, N,N-diethylacrylamide, N,N-dimethylaminopropylacrylamide, tert-butylacrylamide, diacetoneacrylamide, N,N'-methylenebisacrylamide, N-vinyl-N-methylacrylamide, N-vinylpyrrolidone, N-vinylcaprolactam, etc. Among these, from the viewpoint of solubility, acrylamide, N-vinylpyrrolidone, N-vinylcaprolactam, etc. are particularly preferred. There are no particular limitations on other vinyl monomers as long as they can be copolymerized with the vinyl monomer having a nitrogen-containing functional group, and examples thereof include styrene, acrylic acid, vinyl acetate, and long-chain α-olefins.

[0135] As a method for introducing terminal hydrophobic groups into water-soluble polymers, there is no particular restriction, but it is usually preferred to introduce by selecting a chain transfer agent during vinyl polymerization because it is simple. At this time, as a chain transfer agent, as long as the group containing hydrophobic groups such as alkyl, aralkyl, aryl, alkylthio, aralkylthio, arylthio can be introduced into the polymer end obtained, it is not particularly limited. For example, in the case of obtaining a water-soluble polymer with alkylthio, aralkylthio or arylthio as a terminal hydrophobic group, it is preferred to use a chain transfer agent with a hydrophobic group corresponding to these terminal hydrophobic groups, specifically using mercaptan, disulfide, thioether, etc. to carry out vinyl polymerization. As such a chain transfer agent, for example, can be cited: n-dodecyl mercaptan, tert-dodecyl mercaptan, n-octyl mercaptan, 2-ethylhexyl mercaptan, n-octadecyl mercaptan, etc. These can be used alone or in combination of two or more.

[0136] As the polymerization initiator used in the vinyl polymerization, azobismethylbutyronitrile and a polymerization initiator having a terminal hydrophobic group can be used. Examples of the polymerization initiator having a terminal hydrophobic group include a polymerization initiator having a linear or branched alkyl group having 6 to 20 carbon atoms and having no cyano group or hydroxyl group, specifically, dilauroyl peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-tert-hexyl peroxide, di(2-ethylhexyl) peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, di(3,5,5-trimethylhexanoyl) peroxide, etc. These may be used alone or in combination of two or more.

[0137] The main chain portion of the water-soluble polymer is water-soluble and has a nitrogen-containing functional group. The number of units in the main chain portion (polymerization degree) is preferably 2 to 1000 in one molecule, more preferably 2 to 100, and particularly preferably 2 to 50. When the number of units in the main chain portion having a nitrogen-containing functional group is too large, the surface activity tends to decrease. The molecular weight ratio of the main chain part to the terminal hydrophobic group part (e.g., alkyl, aralkyl, aryl, alkylthio, aralkylthio, arylthio, etc.) in the water-soluble polymer (mass average molecular weight of the main chain part / mass average molecular weight of the terminal hydrophobic group part) is preferably 0.3 to 170.

[0138] The mass average molecular weight of the water-soluble polymer is preferably 1 to 1,000,000, more preferably 1 to 100,000, further preferably 600 or more and less than 2,000, and particularly preferably 600 to 1,800, based on polyethylene glycol of GPC. If the mass average molecular weight of the water-soluble polymer is above the above lower limit, the coating property of the conductive composition is improved. On the other hand, if the mass average molecular weight of the water-soluble polymer is below the above upper limit, the water solubility of the conductive composition is improved. In particular, if the mass average molecular weight of the water-soluble polymer is 600 or more and less than 2,000, the balance between solubility in water and coating property is excellent in practical use.

[0139] As the surfactant (C), among the above, nonionic surfactants are preferred because they have little influence on the resist layer, and water-soluble polymers having a nitrogen-containing functional group and a terminal hydrophobic group are particularly preferred.

[0140] (Solvent (D)) The solvent (D) is not particularly limited as long as it is a solvent that can dissolve at least the conductive polymer (A) and exhibits the effects of the present invention, but examples thereof include water, organic solvents, and mixed solvents of water and organic solvents. Examples of water include water among the polymerization solvents exemplified above in the description of the method for producing the conductive polymer (A). Examples of the organic solvent include the organic solvents exemplified above as the polymerization solvents in the description of the method for producing the conductive polymer (A). When a mixed solvent of water and an organic solvent is used as the solvent (C), the mass ratio of these solvents (water / organic solvent) is preferably 1 / 100 to 100 / 1, more preferably 2 / 100 to 100 / 2.

[0141] (Optional ingredient) Examples of the optional components include polymer compounds (excluding the conductive polymer (A), the basic compound (B) and the surfactant (C)), additives, and the like. Examples of the polymer compound include polyvinyl alcohol derivatives such as polyvinyl formal and polyvinyl butyral and modified products thereof, starch and modified products thereof (oxidized starch, phosphated starch, cationized starch, etc.), cellulose derivatives (carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose and salts thereof, etc.), polyacrylamide, poly(N-tert-butylacrylamide), polyacrylamides such as polyacrylamide methylpropanesulfonic acid, polyvinyl pyrrolidone, polyacrylic acid (salt), polyethylene glycol, water-soluble alkyd resins, water-soluble melamine resins, water-soluble urea resins, water-soluble phenolic resins, water-soluble epoxy resins, water-soluble polybutadiene resins, water-soluble acrylic resins, water-soluble polyurethane resins, water-soluble acrylic styrene copolymer resins, water-soluble vinyl acetate acrylic copolymer resins, water-soluble polyester resins, water-soluble styrene maleic acid copolymer resins, water-soluble fluororesins and copolymers thereof. Examples of the additive include a pigment, a defoaming agent, an ultraviolet absorber, an antioxidant, a heat resistance improver, a leveling agent, an anti-sagging agent, a matting agent, and an antiseptic.

[0142] (content) The content of the conductive polymer (A) is preferably 0.1 to 5% by mass, more preferably 0.2 to 3% by mass, and even more preferably 0.5 to 2% by mass, based on the total mass of the conductive composition. The content of the conductive polymer (A) is preferably 50 to 99.9 mass %, more preferably 80 to 99.9 mass %, and even more preferably 95 to 99.9 mass %, relative to the total mass of the solid content of the conductive composition. The solid content of the conductive composition is the residue after removing the solvent (D) from the conductive composition. When the content of the conductive polymer (A) is within the above range, the coating properties of the conductive composition and the conductivity of a conductive film formed from the conductive composition will be well balanced.

[0143] The content of the basic compound (B) is preferably 5 to 80 parts by mass, more preferably 5 to 50 parts by mass, and further preferably 5 to 30 parts by mass relative to 100 parts by mass of the conductive polymer (A). If the content of the basic compound (B) is above the above lower limit, even if the conductive polymer (A) contains an acidic group, it fully forms a salt with the acidic group or oxidant of the conductive polymer (A), and the acidic group is difficult to detach. In addition, the basic compound (B) also fully forms a salt with the decomposition product of the oxidant. Therefore, the migration of the decomposition product of the acidic group or the oxidant to the resist layer can be suppressed, and the film loss of the resist layer can be suppressed. If the content of the basic compound (B) is below the above upper limit, the content of the conductive polymer (A) in the conductive composition can be fully ensured, so that a conductive film with good conductivity can be formed. In addition, in the case where the conductive polymer (A) contains an acidic group, the acidic group does not form a salt with the basic compound (B) in the conductive film and exists moderately in a free state, so that the conductivity can be well maintained. In particular, when the conductive polymer (A) has an acidic group or a salt thereof, the content of the basic compound (B) is preferably 0.1 to 1 mol equivalent, more preferably 0.1 to 0.9 mol equivalent, per 1 mol of the unit having the acidic group in the unit constituting the conductive polymer (A), from the viewpoint of further improving the coating properties of the conductive composition. Furthermore, from the viewpoint of excellent performance retention as a conductive film and being able to further stabilize the acidic group in the conductive polymer (A), it is particularly preferably 0.25 to 0.85 mol equivalent.

[0144] The content of the surfactant (C) is preferably 5 to 200 parts by mass, more preferably 10 to 100 parts by mass, based on 100 parts by mass of the conductive polymer (A). When the content of the surfactant (C) is within the above range, the coating properties of the conductive composition on the resist layer are further improved.

[0145] The content of the solvent (D) is preferably 1 to 99 mass %, more preferably 10 to 98 mass %, and further preferably 50 to 98 mass %, relative to the total mass of the conductive composition. When the content of the solvent (D) is within the above range, coating properties are further improved. It should be noted that when the conductive polymer (A) is used in a state where it is dispersed or dissolved in an aqueous medium after purification (hereinafter, the conductive polymer (A) in this state is referred to as a "conductive polymer solution"), the aqueous medium derived from the conductive polymer solution is also included in the content of the solvent (D) in the conductive composition. In addition, the total amount of all components constituting the conductive composition does not exceed 100 mass %.

[0146] (Method for producing conductive composition) The conductive composition can be obtained, for example, by mixing the conductive polymer (A) and the solvent (D) described above, and, if necessary, the basic compound (B), the surfactant (C), and one or more of the optional components. For example, the conductive polymer (A) produced and washed by the above-mentioned method for producing the conductive polymer (A) is in a solid state, so the solid conductive polymer (A), the solvent (D), and the basic compound (B) as required, the surfactant (C) and one or more of the arbitrary components are mixed to prepare a conductive composition. It should be noted that, when using a conductive polymer (A) that is further purified by an ion exchange method after washing, the conductive polymer (A) after the ion exchange treatment is obtained in the state of a conductive polymer solution as described above. Therefore, the conductive polymer solution can be directly made into a conductive composition, and the conductive polymer solution can also be diluted with a solvent (D). In addition, a basic compound (B), a surfactant (C) and one or more of the optional components can be added to the conductive polymer solution as needed to make a conductive composition, and it can also be further diluted with a solvent (D).

[0147] <Effects> In the above-described method for manufacturing a conductive film of the present invention, since the conductive film is irradiated with a laser beam having a wavelength whose extinction coefficient k is less than 0.2 to inspect the defects of the conductive film, the conductive film is unlikely to absorb the laser beam, and when there are defects on the conductive film, the defects are easily detected, and the detection accuracy is high. Therefore, according to the method for manufacturing a conductive film of the present invention, a high-quality conductive film and a substrate with a conductive film can be provided.

[0148] <Purpose> The method for producing a conductive film of the present invention can be applied to, for example, a method for producing a mask blank with a conductive film, a method for producing a mask, and a method for producing a semiconductor device.

[0149] [Method for manufacturing mask blank with conductive film] One embodiment of a method for producing a mask blank with a conductive film will be described. The method for producing a mask blank with a conductive film according to the present embodiment includes a step of forming a conductive film on the mask blank using the method for producing a conductive film of the present invention described above. Specifically, it is as follows.

[0150] First, a mask blank is used as a base material, and a conductive film is formed on the mask blank to obtain a mask blank with a conductive film. The method for forming the conductive film is the same as the above-mentioned film forming step. It should be noted that it is preferred to form a resist layer on the mask blank before forming a conductive film on the mask blank. That is, it is preferred to form the conductive film on the resist layer of the mask blank on which the resist layer is formed. The method for forming the resist layer is the same as the resist layer forming step described above.

[0151] As the mask blank, a known mask blank can be used, and a mask corresponding to the configuration of the target mask may be used. As a specific example of the mask blank, there is a mask blank including a light-transmitting substrate and a thin film provided on the light-transmitting substrate. As a light-transmitting substrate, soda-lime glass, low expansion glass, quartz glass etc. are mentioned, for example. Examples of the thin film include a light shielding film, an antireflection film, a phase shift film, an anti-oxidation film, etc. The thin film may have a single-layer structure or a multi-layer structure.

[0152] Next, after forming a conductive film on the mask blank, the mask blank is irradiated with laser light to inspect defects of the mask blank. The defect inspection method is the same as the above-mentioned inspection step. It should be noted that, before inspecting the mask blank for defects, it is preferable to determine the wavelength of the laser light to be irradiated onto the mask blank based on the extinction coefficient k of the conductive film.

[0153] In the method for manufacturing a mask blank with a conductive film of the present embodiment described above, since the mask blank is irradiated with a laser beam having a wavelength whose extinction coefficient k of the conductive film is 0.2 or less to detect defects of the mask blank, the conductive film is unlikely to absorb the laser beam, and when there are defects in the mask blank, the defects are easily detected with high detection accuracy. Therefore, according to the method for manufacturing a mask blank with a conductive film of the present embodiment, a high-quality mask blank with a conductive film can be provided.

[0154] [Mask Manufacturing Method] An embodiment of the method for producing a mask according to the present invention will be described. The method for manufacturing a mask according to the present embodiment includes: a step of manufacturing a mask blank with a conductive film; and a step of manufacturing a mask using the obtained mask blank with a conductive film. Specifically, it is as follows.

[0155] First, a mask blank with a conductive film is manufactured. For example, the mask blank with a conductive film can be manufactured by forming a conductive film on a mask blank using the above-mentioned method for manufacturing a conductive film of the present invention, or the mask blank with a conductive film can be manufactured using the above-mentioned method for manufacturing a mask blank with a conductive film. It should be noted that it is preferred to form a resist layer on the mask blank before forming a conductive film on the mask blank. That is, it is preferred to manufacture the mask using a mask blank with a conductive film in which a resist layer and a conductive film are sequentially formed on the mask blank. The mask blank with the conductive film thus obtained is inspected for defects in the mask blank.

[0156] Next, a mask is manufactured using the mask blank with a conductive film that has been inspected for defects, i.e., has passed the inspection for defects of the mask blank. The mask manufacturing process includes, for example, the following steps of irradiating with ionizing radiation, washing and developing, etching, and removing the resist layer.

[0157] The ionizing radiation irradiation step is a step of irradiating the resist layer of the mask blank with a conductive film in a pattern. Specifically, the mask blank with a conductive film is irradiated with ionizing radiation from the conductive film side. Examples of the ionizing radiation include charged particle beams such as electron beams and ion beams, and electromagnetic waves such as X-rays and gamma rays. By the ionizing radiation irradiation step, a latent image is formed on the resist layer between the mask blank and the conductive film. When the resist layer is composed of a chemically amplified resist, an acid is generated by the acid generator in the ionizing radiation irradiation portion. At this time, since a conductive film is provided on the surface of the resist layer, the conductive film can be grounded, and the mask blank with the conductive film can be prevented from being charged as a whole. Therefore, the positional displacement of electrons incident on the resist layer due to the influence of charging can be suppressed, and a latent image corresponding to the target resist pattern can be formed with high precision.

[0158] The water washing / developing step is a step of removing the conductive film by water washing and developing the resist layer to form a resist pattern. The conductive film is water-soluble, so when washing with water, the conductive film is dissolved and removed. Washing with water means contacting with an aqueous liquid. Examples of the aqueous liquid include pure water, water containing at least one of a base and a basic salt, water containing an acid, and a mixture of water and a water-soluble organic solvent.

[0159] When the positive resist layer is developed, the ionizing radiation irradiated portion of the positive resist layer is dissolved and removed, thereby forming a resist pattern consisting of the ionizing radiation non-irradiated portion of the positive resist layer. On the other hand, when the negative resist layer is developed, in contrast to the positive resist layer, the portion not irradiated with ionizing radiation is dissolved and removed, thereby forming a resist pattern consisting of the portion irradiated with ionizing radiation of the negative resist layer.

[0160] The water washing / development step can be performed, for example, by the following method (α) or (β). Method (α): Water washing Using an alkaline developer, the resist layer is developed while removing the conductive film. Method (β): Only the conductive film is removed by washing with water, and then the resist layer is developed with a developer.

[0161] The alkaline developer (alkaline aqueous solution) used in the method (α) is not particularly limited, and a known developer can be used, for example, a tetramethylammonium hydroxide aqueous solution and the like. The water washing in the method (β) can be performed using an aqueous liquid that is not a developer, such as water, etc. The development can be performed using an alkaline developer in the same manner as in the method (α).

[0162] Furthermore, after the water washing / development step, the substrate may be rinsed with pure water or the like as necessary. After the water washing / development step or the rinse treatment, the substrate on which the resist pattern is formed may be heated (post-baked) as necessary.

[0163] The etching step is a step of etching the thin film of the mask blank using the resist pattern as a mask. By etching, the thin film of the portion not masked (ie, the exposed portion) in the resist pattern is removed. As the etching method, a known method itself can be adopted, for example, dry etching, wet etching, etc. are mentioned.

[0164] The resist removal step is a step of removing the resist pattern remaining on the mask blank after etching. By removing the resist pattern, a mask (photomask) having a pattern formed thereon is obtained. To remove the resist pattern, a known stripping agent can be used.

[0165] The method for manufacturing a mask of the present embodiment may further include a step of inspecting defects on the mask blank as a substrate by laser irradiation after removing the conductive film (hereinafter also referred to as a "second inspection step"). That is, the second inspection step is a step of inspecting defects on the mask blank from which the conductive film has been removed by laser irradiation. The second inspection process can be between the washing / developing process and the etching process, between the etching process and the resist removal process, or after the resist removal process. In addition, when the washing / developing process is performed by method (β), the second inspection process can be between the washing process and the developing process.

[0166] The wavelength of the laser light used in the second inspection step is not particularly limited. Defects on the mask blank after the conductive film is removed are specifically detected as follows. First, the mask blank is irradiated with laser light. When a resist layer remains on the mask blank, the resist layer is irradiated with laser light. When there is a defect on the mask blank after the conductive film is removed, the laser beam irradiated to the defect is scattered. The scattered laser beam is detected by the detector, and the defect on the mask blank after the conductive film is removed, that is, the defect on the substrate is detected.

[0167] In the above-described method for manufacturing a mask of the present invention, since the mask blank with a conductive film obtained by the above-described method for manufacturing a mask blank with a conductive film of the present invention is used, defect detection accuracy is high, and a high-quality mask can be provided.

[0168] [Method for manufacturing semiconductor device] An embodiment of a method for manufacturing a semiconductor device according to the present invention will be described. The method for manufacturing a semiconductor device according to the present embodiment includes: a step of forming a conductive film on a substrate to obtain a laminated body using the method for manufacturing a conductive film of the present invention described above; and a step of manufacturing a semiconductor device using the laminated body. Specifically, it is as follows.

[0169] First, a conductive film is formed on a substrate to obtain a laminate. The method for forming the conductive film is the same as the above-mentioned film forming step. It should be noted that, it is preferred to form a resist layer on the substrate before forming the conductive film on the substrate. That is, it is preferred to use a substrate with a resist layer, form a conductive film on the resist layer of the substrate with the resist layer, and use a laminated body in which the resist layer and the conductive film are sequentially formed on the substrate to manufacture a semiconductor device. The method for forming the resist layer is the same as the above-mentioned resist layer forming step. As the substrate, a known substrate used as a substrate for a semiconductor device can be used, for example, a silicon wafer or the like.

[0170] Next, after forming a conductive film on the substrate, the conductive film formed on the substrate is irradiated with laser light to inspect the mask blank for defects. The defect inspection method is the same as the above-mentioned inspection step. It should be noted that, before inspecting defects of the conductive film, it is preferable to determine the wavelength of the laser light to be irradiated onto the mask blank based on the extinction coefficient k of the conductive film. The laminated body obtained in this way is inspected for defects in the mask blank.

[0171] Next, a semiconductor device is manufactured using the laminated body that has been inspected for defects, i.e., has been judged to be acceptable by the defect inspection of the mask blank. The manufacturing process of the semiconductor device includes, for example, an ionizing radiation irradiation process as shown below. In addition, the following processes are also included as needed: a water washing process as shown below; a developing process; an etching process; and a resist layer removal process.

[0172] The ionizing radiation irradiation step is a step of irradiating the laminate with ionizing radiation such as electron beams and ion beams to form a wiring pattern. At this time, since a conductive film is provided on the surface of the substrate or the resist layer, the conductive film can be grounded, and the entire laminate can be prevented from being charged. Therefore, the positional displacement of electrons incident on the substrate or the resist layer due to the influence of charging can be suppressed, and a latent image corresponding to the transferred pattern can be formed with high precision.

[0173] The washing step and the developing step are the same as the washing / developing step in the above-mentioned method for manufacturing the mask. The washing step and the developing step may be performed simultaneously (the above-mentioned method (α)), or the developing step may be performed after the washing step (the above-mentioned method (β)). The etching step is the same as the etching step in the above-mentioned method of manufacturing the mask. The resist layer removal step is the same as the resist layer removal step in the above-mentioned mask manufacturing method.

[0174] The method for manufacturing a semiconductor device of this embodiment may further include a step of inspecting defects on the substrate by laser irradiation after removing the conductive film (hereinafter also referred to as a "third inspection step"). That is, the third inspection step is a step of inspecting defects on the substrate from which the conductive film has been removed by laser irradiation. The third inspection step may be performed between the water washing step and the developing step, between the developing step and the etching step, between the etching step and the resist removing step, or after the resist removing step.

[0175] In the method for manufacturing a semiconductor device of the present invention described above, since the conductive film is irradiated with a laser beam having a wavelength whose extinction coefficient k is less than 0.2 to inspect the defects of the conductive film, the conductive film is unlikely to absorb the laser beam, and when there are defects on the conductive film, the defects are easily detected, and the detection accuracy is high. Therefore, according to the method for manufacturing a semiconductor device of the present invention, a high-quality semiconductor device can be provided.

[0176] [Example of extinction coefficient] The extinction coefficient of a 30 nm conductive film containing polyaniline sulfonic acid at a specific wavelength measured by an ultraviolet visible spectrophotometer is shown in Table 1. Thus, it is considered that if the extinction coefficient of the conductive film is 0.20 or less, absorption of laser light can be suppressed, making it easy to detect defects.

[0177] [Table 1] Wavelength (nm) Extinction coefficient 550 0.03 650 0.03 800 0.01

Claims

1. A method for manufacturing a conductive film, comprising the following steps: an inspection step of irradiating the conductive film with laser light to inspect defects of the conductive film, In the inspection step, the conductive film is irradiated with laser light having a wavelength at which the extinction coefficient k of the conductive film is 0.2 or less.

2. The method for producing a conductive film according to claim 1, further comprising the following steps: A film forming step of forming the conductive film on a substrate.

3. The method for producing a conductive film according to claim 2, wherein: forming a resist layer on the substrate, The film forming step is a step of forming the conductive film on the resist layer.

4. The method for manufacturing a conductive film according to claim 1, further comprising the following steps: A step of determining a wavelength of the laser beam to be irradiated onto the conductive film based on an extinction coefficient k of the conductive film.

5. The method for producing a conductive film according to any one of claims 1 to 4, wherein: The wavelength of the laser is 600-1000nm.

6. The method for producing a conductive film according to any one of claims 1 to 4, wherein: The wavelength of the laser is 700-900 nm.

7. The method for producing a conductive film according to any one of claims 1 to 4, wherein: The conductive film includes a conductive polymer having at least one unit selected from the group consisting of units represented by the following formulae (1) to (4), [Chemistry 1] [Chemistry 2] [Chemistry 3] [Chemistry 4] In formulas (1) to (4), X represents a sulfur atom or a nitrogen atom, and R 1 ~R 15 Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group or a salt thereof, a hydroxyl group, a nitro group, a halogen atom, -N(R 16 2. -NHCOR 16 、-SR 16 、-OCOR 16 、-COOR 16 、-COR 16 , -CHO or -CN; R 16 represents an alkyl group having 1 to 24 carbon atoms, an aryl group having 6 to 24 carbon atoms, or an aralkyl group having 7 to 24 carbon atoms, Among them, R in formula (1) 1 and R 2 At least one of the formula (2) 3 ~R 6 At least one of the formula (3) 7 ~R 10 At least one of the above and R of formula (4) 11 ~R 15 At least one of them is an acidic group or a salt thereof.

8. The method for producing a conductive film according to any one of claims 1 to 4, wherein: The conductive film includes a conductive polymer having a unit represented by the following formula (4): [Chemistry 5] In formula (4), R 11 ~R 15 Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group or a salt thereof, a hydroxyl group, a nitro group, a halogen atom, -N(R 16 2. -NHCOR 16 、-SR 16 、-OCOR 16 、-COOR 16 、-COR 16 , -CHO or -CN; R 16 represents an alkyl group having 1 to 24 carbon atoms, an aryl group having 6 to 24 carbon atoms, or an aralkyl group having 7 to 24 carbon atoms, Among them, R in formula (4) 11 ~R 15 At least one of them is an acidic group or a salt thereof.

9. The method for producing a conductive film according to any one of claims 1 to 4, wherein: The conductive film includes at least one selected from a conductive polymer, a basic compound, and a surfactant.

10. The method for producing a conductive film according to any one of claims 1 to 4, wherein: The conductive film includes at least one selected from a conductive polymer, a basic compound, and a surfactant, wherein the conductive polymer has at least one unit selected from units represented by the following formulae (1) to (4). [Chemistry 6] [Chemistry 7] [Chemistry 8] [Chemistry 9] In formulas (1) to (4), X represents a sulfur atom or a nitrogen atom, and R 1 ~R 15 Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group or a salt thereof, a hydroxyl group, a nitro group, a halogen atom, -N(R 16 2. -NHCOR 16 、-SR 16 、-OCOR 16 、-COOR 16 、-COR 16 , -CHO or -CN; R 16 represents an alkyl group having 1 to 24 carbon atoms, an aryl group having 6 to 24 carbon atoms, or an aralkyl group having 7 to 24 carbon atoms, Among them, R in formula (1) 1 and R 2 At least one of the formula (2) 3 ~R 6 At least one of the formula (3) 7 ~R 10 At least one of the above and R of formula (4) 11 ~R 15 At least one of them is an acidic group or a salt thereof.

11. The method for producing a conductive film according to any one of claims 1 to 4, wherein: The conductive film has a thickness of 1 to 100 nm.

12. The method for producing a conductive film according to any one of claims 1 to 4, wherein: The light intensity of the laser is 1 mW to 200W.

13. A method for manufacturing a mask, comprising the following steps: A step of manufacturing a mask blank with a conductive film using the method for manufacturing a conductive film according to claim 2 or 3; A step of manufacturing a mask using the obtained mask blank with a conductive film.

14. The method for manufacturing a mask according to claim 13, further comprising the following steps: A step of inspecting defects on the mask blank as a base material by laser irradiation after removing the conductive film from the mask blank with the conductive film.

15. A method for manufacturing a semiconductor device, comprising the following steps: A step of forming the conductive film on the substrate using the conductive film manufacturing method according to claim 2 or 3 to obtain a laminated body; A process of manufacturing a semiconductor device using the laminated body.

16. The method for manufacturing a semiconductor device according to claim 15, further comprising the following steps: A step of inspecting defects on the substrate by laser irradiation after removing the conductive film.

17. A defect inspection method for a conductive film, comprising irradiating the conductive film with laser light having a wavelength such that the extinction coefficient k of the conductive film is 0.2 or less.

18. A defect inspection device, which takes a conductive film as a measurement object, comprising: An irradiation portion of a laser beam having a wavelength of which the extinction coefficient k of the conductive film is 0.2 or less; An inspection portion for analyzing the presence or absence of defects based on scattered light from the conductive film.

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