Method for manufacturing a conductive film, method for manufacturing a mask, method for manufacturing a semiconductor device, method for inspecting defects in a conductive film, and apparatus for inspecting defects

Abstract

The present invention provides a manufacturing method for a conductive film having high accuracy in detecting a defect. The manufacturing method includes an examination step for irradiating a conductive film with a laser beam to examine a defect in the conductive film. In the examination step, the conductive film is irradiated with a laser beam having a wavelength by which an extinction coefficient k of the conductive film becomes 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 in a conductive film, and a defect inspection apparatus. This application claims priority based on Japanese Patent Application No. 2022-146118 filed in Japan on September 14, 2022, and incorporates the contents herein by reference.

Background Art

[0002] Pattern formation technology using ionizing radiation such as an electron beam or an ion beam is expected as a next-generation technology for photolithography. In the manufacture of semiconductor devices, various patterns are formed on a substrate such as a wafer by photolithography using, for example, a photomask. If there are defects on the substrate or the photomask, it will affect pattern formation, so defect inspection is one of the important processes.

[0003] As a method for inspecting defects, for example, an inspection method using laser irradiation is known. For example, as a light source of an apparatus for detecting defects on a substrate or a mask, a laser light source that generates 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, light with a shorter wavelength having higher sensitivity for detecting minute defects has come to be used.

[0004] By the way, in a pattern formation method using ionizing radiation, particularly when the substrate is insulating, there is a problem that the trajectory of the ionizing radiation is bent due to an electric field generated by charging (charge-up) of the substrate, and it is difficult to obtain a desired pattern. As a means for solving this problem, it is already known that a technique of applying a conductive composition containing a conductive polymer to the surface of a resist layer to form a conductive film and covering the surface of the resist layer with the conductive film is effective (see Patent Document 3).

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2008-268041 [Patent Document 2] Japanese Patent Publication No. 2018-198293 [Patent Document 3] International Publication No. 2014 / 017540 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, conventional defect inspection methods make it difficult to detect defects in conductive films. The present invention aims 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 in a conductive film, and a defect inspection apparatus. [Means for solving the problem]

[0007] As the wavelength of a laser decreases, it tends to scatter more easily when it hits foreign objects or defects such as scratches. Therefore, to detect minute defects on a substrate or mask, it is common to use a short-wavelength laser, as described in Patent Documents 1 and 2. However, the inventors have discovered that in conductive films formed on a substrate, the conductive film absorbs the laser, making it difficult for the laser to scatter even when it hits a defect, thus making it difficult to detect the defect. Therefore, the inventors focused on the extinction coefficient k of the conductive film and, based on the idea that irradiating the conductive film with a laser of a wavelength such that the extinction coefficient k is 0.2 or less would make it less likely for the laser to be absorbed by the conductive film, thus making it easier to detect defects in the conductive film, they completed the present invention. In other words, the present invention has the following aspects.

[0008] [1] Includes an inspection step of irradiating a conductive film with a laser to inspect for defects in the conductive film, A method for manufacturing a conductive film, wherein in the inspection step, the conductive film is irradiated with a laser having a wavelength such that the extinction coefficient k of the conductive film is 0.2 or less.

[0009] [2] A method for manufacturing a conductive film, comprising an inspection step of irradiating the conductive film with a laser of a wavelength determined such that the extinction coefficient k of the conductive film is 0.2 or less to inspect for defects in the conductive film.

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

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

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

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

[0014] [7] A determination step of determining the wavelength of the laser to irradiate the conductive film based on the extinction coefficient k of the conductive film. A method for manufacturing a conductive film according to any one of [1] to [6], further comprising:

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

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

[0017]

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

[0018]

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

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

[0019]

[12] The method for manufacturing 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 formulas (1) to (4).

[0020] [Chemical formula]

[0021] [Chemical formula]

[0022] [Chemical formula]

[0023] [Chemical formula]

[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 its salt, a hydroxy 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 16This 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. However, R in equation (1) 1 and R 2 At least one of the R values ​​in equation (2) 3 ~R 6 At least one of the R values ​​in equation (3) 7 ~R 10 At least one of the following, and R of equation (4) 11 ~R 15 At least one of them is an acidic group or a salt thereof.

[0025]

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

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

[0026] [ka] In formula (4), R 11 ~R 15 Each of these independently comprises 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 its salt, a hydroxyl group, a nitro group, a halogen atom, and -N(R 16 )2, -NHCOR 16 , -SR 16 , -OCOR 16 ,-COOR 16 , -COR 16 R represents -CHO or -CN. 16 This 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. However, R in equation (4) 11 ~R 15 At least one of them is an acidic group or a salt thereof.

[0027]

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

[11] , wherein the conductive film comprises a conductive polymer and at least one selected from the group consisting of basic compounds and surfactants.

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

[11] , wherein the conductive film comprises a conductive polymer having at least one unit selected from the group consisting of units represented by the following formulas (1) to (4), and at least one selected from the group consisting of basic compounds and surfactants.

[0028] [ka]

[0029] [ka]

[0030] [ka]

[0031] [ka]

[0032] In equations (1) to (4), X represents a sulfur atom or a nitrogen atom, and R 1 ~R 15 Each of these independently comprises 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 its salt, a hydroxyl group, a nitro group, a halogen atom, and -N(R 16 )2, -NHCOR 16 , -SR 16 , -OCOR 16 ,-COOR 16 , -COR 16 R represents -CHO or -CN. 16 This 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. However, R in equation (1) 1 , R 2 At least one of the R values ​​in equation (2) 3 ~R 6 At least one of the R values ​​in equation (3)7 ~R 10 At least one of the R values ​​in equation (4) 11 ~R 15 At least one of them is an acidic group or a salt thereof.

[0033]

[16] A method for manufacturing a conductive film according to any one of [1] to

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

[0034]

[17] A method for manufacturing a conductive film according to any one of [1] to

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

[0035] A method for manufacturing a mask blank with a conductive film, comprising the step of forming the conductive film on a mask blank which is a base material using the method for manufacturing a conductive film described in any of [1] to

[17] .

[0036] A step of manufacturing a conductive film-coated mask blank using the method for manufacturing conductive film-coated mask blanks described in

[19]

[18] , A process for manufacturing a mask using the obtained conductive film-coated mask blanks and A method for manufacturing masks, including the method described above.

[0037]

[20]

[18] A step to manufacture a mask using a conductive film-coated mask blank obtained by the method for manufacturing conductive film-coated mask blanks described in

[20]

[18] . A method for manufacturing masks, including the method described above.

[0038]

[21] A step of manufacturing a mask blank with a conductive film by forming the conductive film on a mask blank which is a base material using a method for manufacturing a conductive film described in any of [1] to

[17] , A process for manufacturing a mask using the obtained conductive film-coated mask blanks and A method for manufacturing masks, including the method described above.

[0039]

[22] A step of inspecting defects on the mask blank, which is the base material, by laser irradiation after removing the conductive film from the conductive film-coated mask blank. A method for manufacturing a mask according to any one of

[19] to

[21] , further including the following:

[0040]

[23] A step of inspecting defects on the mask blank, which is a base material from which the conductive film has been removed from the conductive film-coated mask blank, by laser irradiation. A method for manufacturing a mask according to any one of

[19] to

[21] , further including the following:

[0041]

[24] A step of forming the conductive film on the substrate using a method for manufacturing a conductive film described in any of [3] to [6] to obtain a laminate, A process for manufacturing a semiconductor device using the aforementioned laminate, A method for manufacturing semiconductor devices, including [the specified element].

[0042]

[25] A process for manufacturing a semiconductor device using a laminate having a conductive film obtained by a conductive film manufacturing method described in any of [1] to

[17] . A method for manufacturing semiconductor devices, including [the specified element].

[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] A step of inspecting defects on the substrate by laser irradiation after removing the conductive film. A method for manufacturing a semiconductor device according to

[24] or

[26] , further comprising:

[0045]

[28] A 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 has been removed by laser irradiation.

[0046]

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

[0047]

[30] Conductive films are used as the measurement target, A laser irradiation section with a wavelength such that the extinction coefficient k of the conductive film is 0.2 or less, An inspection unit that analyzes the presence or absence of defects based on scattered light from the conductive film. A defect inspection device equipped with the following features. [Effects of the Invention]

[0048] According to the present invention, it is possible to provide a method for manufacturing a conductive film with high defect detection accuracy, a method for manufacturing a mask, and a method for manufacturing a semiconductor device. [Brief explanation of the drawing]

[0049] [Figure 1] Figure 1 is a schematic cross-sectional view of an example of a laminate according to an embodiment of the present invention. [Figure 2] Figure 2 is a schematic cross-sectional view of another example of a laminate according to an embodiment of the present invention. [Modes for carrying out the invention]

[0050] The present invention will now be described in detail. The following embodiments are merely illustrative for illustrating 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 its spirit.

[0051] In this invention, "conductive" means 1 × 10 11 The surface resistivity must be less than or equal to Ω / □. Surface resistivity is measured per unit area (1 cm²) of the test specimen. 2 This is the surface resistance value per unit area. The surface resistance value can be determined from the potential difference between electrodes when a constant current is passed through them. In this specification, "solubility" means that 0.1 g or more of the substance is uniformly dissolved in 10 g (at a liquid temperature of 25°C) of one or more solvents selected from plain water, water containing at least one of a base and a basic salt, water containing an acid, or a mixture of water and a water-soluble organic solvent. Furthermore, "water solubility" in relation to the above solubility means solubility in water. In this specification, the term "terminal hydrophobic group" means a part other than the repeating units that make up the polymer. In this specification, "mass-average molecular weight" refers to the mass-average molecular weight measured by gel permeation chromatography (GPC) (in terms of sodium polystyrene sulfonate or polyethylene glycol). In this specification, a numerical range represented by "~" means a range that includes the numbers written before and after "~" as the lower and upper limits, respectively.

[0052] [Method for manufacturing conductive films] One embodiment of the method for manufacturing a conductive film according to the present invention will be described.

[0053] The method for manufacturing the conductive film of this embodiment includes the inspection steps described below.

[0054] The method for manufacturing the conductive film of this embodiment may further include the following film formation steps. The method for manufacturing the conductive film of this embodiment may further include the following substrate preparation step before the film formation step, and may further include the following resist layer formation step 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 determination step.

[0056] <Laminate> In the method for manufacturing a conductive film according to this embodiment, the conductive film is, for example, a conductive film 12 formed on the surface of a substrate 11 in a laminate 1 shown in Figure 1, or a conductive film 12 formed on the surface of a resist layer 13 opposite to the substrate 11 in a laminate 2 shown in Figure 2. The laminate 1 shown in Figure 1 is a laminate comprising a substrate 11 and a conductive film 12. The laminate 1, which has a conductive film 12 on a substrate 11, can be prepared, for example, by a substrate preparation step and a film formation step described later. The laminate 2 shown in Figure 2 is a laminate comprising 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. The laminate 2, which comprises a resist layer 13 and a conductive film 12 on a substrate 11, can be prepared, for example, by a substrate preparation step, a resist layer formation step, and a film formation step, as described later.

[0057] <Base material preparation process> The substrate preparation process is the process of preparing the substrate, which is the base portion of the conductive film. Examples of substrates include molded products of various polymer compounds such as polyester resins like polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polyolefin resins represented by polyethylene and polypropylene, vinyl chloride, nylon, polystyrene, polycarbonate, epoxy resin, fluororesin, polysulfone, polyimide, polyurethane, phenolic resin, silicone resin, and synthetic paper, as well as films, paper, iron, glass, quartz glass, various wafers, various mask blanks, aluminum, copper, zinc, nickel, stainless steel, etc., and substrates on which various paints or photosensitive resins are coated. The shape of the substrate is not particularly limited; it may be in the form of a plate or other shapes.

[0058] <Resist layer formation process> The resist layer formation process is the process of forming a resist layer on a substrate. In this invention, a substrate on which a resist layer is formed is also referred to as a "substrate with a resist layer."

[0059] The resist layer is obtained by coating a resist onto a substrate. Examples of resists include positive resists and negative resists. Positive-type resists are not particularly limited as long as they are sensitive to ionizing radiation, and known ones can be used. Typical examples include chemically amplified resists containing an acid generator that generates acid upon irradiation with ionizing radiation and a polymer containing constituent units having acid-degradable groups. The negative-type resist is not particularly limited as long as it is sensitive to ionizing radiation, and known types can be used. Typically, a chemically amplified resist contains an acid generator that generates acid upon irradiation with ionizing radiation, a polymer soluble in the developer, and a crosslinking agent.

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

[0061] <Film formation process> The film formation process is a step in which a conductive film is formed on a substrate or a resist layer before the inspection process described later, thereby preparing the conductive film that will be inspected in the inspection process. A conductive film is obtained by coating a conductive composition onto a substrate or a resist layer and drying it. If necessary, the conductive composition may be heat-treated after drying. If a resist layer is formed on the substrate, a conductive film is formed on the resist layer of the substrate with the resist layer. If a resist layer is not formed on the substrate, a conductive film is formed directly on the surface of the substrate. The conductive film is preferably a conductive film formed on a substrate, or a conductive film formed on the resist layer of a substrate with a resist layer. Furthermore, the thickness of the conductive film is usually 1 to 100 nm. From the viewpoint of accurate pattern formation, it is preferably 10 to 80 nm, and more preferably 10 to 60 nm. The upper limit of the aforementioned film thickness is preferably 80 nm, more preferably 60 nm, and even more preferably 50 nm. The lower limit of the aforementioned film thickness is preferably 5 nm, more preferably 10 nm, and even more preferably 15 nm.

[0062] Examples of methods for applying conductive compositions include spin coating, spray coating, dip coating, roll coating, gravure coating, reverse coating, roll brushing, air knife coating, and curtain coating. The drying temperature for the conductive composition is not particularly limited, but is preferably less than 40°C. The drying time for the conductive composition is not particularly limited, but is preferably within 1 hour. When heat-treating a conductive composition after drying, the heat treatment temperature is preferably in the range of 40°C to 250°C, and more preferably in the range of 60°C to 200°C, from the viewpoint of conductivity. The heat treatment time is preferably within 1 hour, and more preferably within 30 minutes, from the viewpoint of stability. 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. Details of the conductive composition will be described later.

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

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

[0065] In the determination step, the extinction coefficient k may be measured using the conductive film that will actually be irradiated with the laser in the inspection step described later, and the wavelength of the laser irradiated onto the conductive film may be determined. Alternatively, a separate conductive film may be prepared to have the same composition as the conductive film contained in the conductive film that will actually be irradiated with the laser in the inspection step, and the wavelength of the laser irradiated onto the conductive film may be measured using this separately prepared conductive film. If a separate conductive film is prepared, the thickness of the conductive film may be, for example, 30 nm.

[0066] <Inspection Process> The inspection process involves irradiating the conductive film with a laser to inspect for defects in the conductive film. This inspection process can be performed on any or all conductive films. Hereinafter, this process will also be referred to as the "first inspection process." In the present invention, "defects in the conductive film" refers to defects that occur, for example, when forming a conductive film on a substrate or a resist layer. Furthermore, "defects on the substrate," as described later, refer to defects originating from the substrate, defects that occur when forming a resist layer on the substrate, defects that occur when forming a conductive film on the resist layer, defects that occur when removing a conductive film from a resist layer, defects that occur when removing a resist layer from a substrate, and so on. Furthermore, "defects" refer to deposits, protrusions, scratches, etc., attached to the substrate, resist layer, or conductive film.

[0067] In the inspection process, the conductive film is irradiated with a laser of a wavelength such that 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 irradiated onto the conductive film is 0.2 or less. If a laser with a wavelength such that the extinction coefficient k of the conductive film is 0.2 or less is irradiated onto the conductive film, the conductive film will not easily absorb the laser. Therefore, if there are defects in the conductive film, the laser will be easily scattered when it hits the defects, making it easier to detect defects in the conductive film.

[0068] The wavelength of the laser is not particularly limited as long as it is the wavelength at which the extinction coefficient k of the conductive film is 0.2 or less, but it is preferably the wavelength at which the extinction coefficient k is 0.17 or less, more preferably 0.15 or less, even more preferably 0.10 or less, and especially preferably 0.05 or less. Furthermore, the wavelength of the laser is preferably the wavelength at which the extinction coefficient k of the conductive film is 0 to 0.2, more preferably 0.001 to 0.2, more preferably 0.001 to 0.17, even more preferably 0.001 to 0.15, especially preferably 0.001 to 0.10, and particularly preferably 0.001 to 0.05. In particular, from the viewpoint of suppressing the absorption of the conductive film by the irradiated light, the laser wavelength is preferably 600 to 1000 nm, and more preferably 700 to 900 nm. From the standpoint of improving inspection accuracy, the laser light intensity is preferably 1mW to 200W, more preferably 1mW to 100W, even more preferably 1mW to 10W, and particularly preferably 1mW to 1W.

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

[0070] One aspect of the present invention is a method for inspecting defects in a conductive film, which involves irradiating the conductive film with a laser having a wavelength such that the extinction coefficient k of the conductive film is 0.2 or less. Another aspect of the present invention is a defect inspection device that measures a conductive film and includes an irradiation unit for a laser with a wavelength such that the 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. The analysis means in the aforementioned inspection unit can be known means.

[0071] Defects in conductive films are detected specifically as follows: First, a laser of a specific wavelength is irradiated onto the conductive film. If a defect exists in the conductive film, the laser beam that hits the defect will scatter. By detecting this scattered laser beam with a detector, the defect in the conductive film can be detected.

[0072] <Conductive composition> The conductive composition is a composition comprising the conductive polymer (A) and solvent (D) shown below. In addition to the conductive polymer (A) and solvent (D), the conductive composition may further contain at least one selected from the group consisting of the basic compound (B) and surfactant (C) shown below. Furthermore, the conductive composition may further contain components other than the conductive polymer (A), solvent (D), and at least one selected from the group consisting of the basic compound (B) and surfactant (C) (optional components). That is, the conductive film is a film containing the conductive polymer (A). The conductive film may further contain at least one selected from the group consisting of the conductive polymer (A) and basic compound (B) and surfactant (C), or it may further contain optional components in addition to the conductive polymer (A) and at least one selected from the group consisting of the basic compound (B) and surfactant (C).

[0073] (Conductive polymer (A)) Known conductive polymers (A) can be used, such as polythiophene, polythiophene vinylene, poly(3-alkylthiophene), poly(3,4-ethylenedioxy)thiophene (PEDOT), poly3,4-ethylenedioxythiophene-polystyrene sulfonic acid (PEDOT-PSS), polyaniline, polypyrrole, polyterolphene, 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 coatability of the conductive composition is improved, and a conductive film of uniform thickness is easily obtained. The conductive polymer (A) preferably has an acidic group or a salt thereof. The presence of an acidic group or a salt thereof in the conductive polymer (A) increases its water solubility. The conductive polymer (A) may have two types of acidic groups in a single molecule. Some or all of the acidic groups may form a salt.

[0075] Examples of conductive polymers (A) having an acidic group or a salt thereof include those listed in Japanese Patent Publication No. 61-197633, 63-39916, 1-301714, 5-504153, 5-503953, 4-32848, 4-328181, 6-145386, 6-56987, and 5-226238. From the viewpoint of solubility, conductive polymers such as those shown in Japanese Patent Publication No. 5-178989, Japanese Patent Publication No. 6-293828, Japanese Patent Publication No. 7-118524, Japanese Patent Publication No. 6-32845, Japanese Patent Publication No. 6-87949, Japanese Patent Publication No. 6-256516, Japanese Patent Publication No. 7-41756, Japanese Patent Publication No. 7-48436, Japanese Patent Publication No. 4-268331, or Japanese Patent Publication No. 2014-65898 are preferred.

[0076] Examples of conductive polymers (A) include π-conjugated conductive polymers that contain at least one repeating unit selected from the group consisting of phenylenevinylene, vinylene, thienylene, pyrrolylene, phenylene, iminophenylene, isothianaphthene, frilene, and carbazoylene, where the α- or β-position is substituted with at least one group selected from the group consisting of a sulfonic acid group and a carboxyl group. Furthermore, if the π-conjugated conductive polymer includes at least one repeating unit selected from the group consisting of iminophenylene and carbazoylene, examples include conductive polymers having an acidic group or a salt thereof on the nitrogen atom of the repeating unit, or conductive polymers having an alkyl group substituted with an acidic group or a salt thereof, or an alkyl group containing an ether bond on the nitrogen atom. Among these, conductive polymers having at least one selected from the group consisting of thienylene, pyrrolylene, iminophenylene, phenylenevinylene, carbasolylene, and isothianaphthene, in which the β position is substituted with an acidic group or a salt thereof, are preferably used as monomer units (units).

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

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

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] [ka]

[0083] In equations (1) to (4), X represents a sulfur atom or a nitrogen atom, and R 1 ~R 15 Each of these independently consists of 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 its salt, a hydroxyl group, a nitro group, a halogen atom (-F, -Cl, -Br, or -I), and -N(R). 16 )2, -NHCOR 16 , -SR 16 , -OCOR 16 ,-COOR 16 , -COR 16 R represents -CHO or -CN. 16This 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. However, R in equation (1) 1 and R 2 At least one of the R values ​​in equation (2) 3 ~R 6 At least one of the R values ​​in equation (3) 7 ~R 10 At least one of the following, and R of equation (4) 11 ~R 15 At least one of them is an acidic group or a salt thereof.

[0084] Here, "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 an acidic state (-SO3H) or in an ionic state (-SO3 - ) may be included as a substituent (-R 17 SO3H is also included. On the other hand, the carboxylic acid group may be present in an acidic state (-COOH) or in an ionic state (-COO - ) may be included as a substituent (-R 17 This also includes COOH. The aforementioned R 17 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. A sulfonic acid group is preferred as the acidic group.

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

[0086] Examples of alkali metal salts 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 alkaline earth metal salts include magnesium salts and calcium salts.

[0088] Examples of substituted ammonium salts include aliphatic ammonium salts, saturated alicyclic ammonium salts, and unsaturated alicyclic ammonium salts.

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

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

[0091] As for the conductive polymer (A), it is preferable that it has units represented by the above formula (4) from the viewpoint of being able to exhibit high conductivity, and among these, it is more preferable that it has units represented by the following formula (5) from the viewpoint of having excellent solubility.

[0092] [ka]

[0093] In formula (5), R 18 ~R 21 Each of these 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 its salt, a hydroxyl group, a nitro group, or a halogen atom (-F, -Cl, -Br, or -I). Also, R 18 ~R 21 At least one of them is an acidic group or a salt thereof.

[0094] As for the unit represented by the above formula (5), R is easy to manufacture. 18 ~R 21 Preferably, one of these groups is a linear or branched alkoxy group having 1 to 4 carbon atoms, one of the others is a sulfonic acid group or a salt thereof, and the remainder are hydrogen atoms.

[0095] From the viewpoint of having excellent solubility in water and organic solvents regardless of pH, conductive polymer (A) preferably contains 10 to 100 mol% of the units represented by formula (5) out of the total units (100 mol%) constituting the conductive polymer (A), more preferably 50 to 100 mol%, and particularly preferably 100 mol%. Furthermore, from the viewpoint of excellent conductivity, it is preferable that the conductive polymer (A) contains 10 or more units represented by formula (5) in one molecule.

[0096] Furthermore, in conductive polymer (A), from the viewpoint of further improving solubility, the number of aromatic rings to which an acidic group or its salt is bonded, relative to the total number of aromatic rings in the polymer, is preferably 50% or more, more preferably 70% or more, even more preferably 80% or more, particularly preferably 90% or more, and most preferably 100%. The number of aromatic rings to which an acidic group or its salt is attached, relative to the total number of aromatic rings in the polymer, refers to the value calculated from the monomer charging ratio during the production of conductive polymer (A).

[0097] Furthermore, in conductive polymer (A), substituents other than acidic groups or their salts on the aromatic ring of the monomer unit are preferably electron-donating groups from the viewpoint of imparting reactivity to the monomer. Specifically, alkyl groups having 1 to 24 carbon atoms, alkoxy groups having 1 to 24 carbon atoms, halogen groups (-F, -Cl, -Br, or -I), etc., and among these, alkoxy groups having 1 to 24 carbon atoms are most preferred from the viewpoint of electron-donating properties.

[0098] Furthermore, the conductive polymer (A) may contain, as constituent units other than the unit represented by 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, provided that they do not affect its solubility, conductivity, and properties.

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

[0100] [ka]

[0101] In formula (6), R 22 ~R 37Each of these 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 its salt, a hydroxyl group, a nitro group, or a halogen atom (-F, -Cl, -Br, or -I). Also, R 22 ~R 37 At least one of these is an acidic group or a salt thereof. Also, n indicates the degree of polymerization. In this invention, n is preferably an integer between 5 and 2500.

[0102] As for the unit represented by the above formula (6), R is easy to manufacture. 22 ~R 25 Of these, one is a linear or branched alkoxy group having 1 to 4 carbon atoms, one of the others is a sulfonic acid group or a salt thereof, and the rest are hydrogen atoms, R 26 ~R 29 Of these, one is a linear or branched alkoxy group having 1 to 4 carbon atoms, one of the others is a sulfonic acid group or a salt thereof, and the rest are hydrogen atoms, R 30 ~R 33 Of these, one is a linear or branched alkoxy group having 1 to 4 carbon atoms, one of the others is a sulfonic acid group or a salt thereof, and the rest are hydrogen atoms, R 34 ~R 37 Preferably, one of these is a linear or branched alkoxy group having 1 to 4 carbon atoms, one of the others is a sulfonic acid group or a salt thereof, and the remainder are hydrogen atoms.

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

[0104] The mass-average molecular weight of conductive polymer (A), calculated as sodium polystyrene sulfonate of GPC, is preferably 1000 to 1,000,000, more preferably 1500,000 to 800,000, even more preferably 2000 to 500,000, and particularly preferably 2000 to 100,000, from the viewpoint of conductivity, solubility, and film-forming properties. If the mass-average molecular weight of conductive polymer (A) is less than 1,000, solubility may be excellent, but conductivity and film-forming properties may be insufficient. On the other hand, if the mass-average molecular weight exceeds 1,000,000, conductivity may be excellent, but solubility may be insufficient. Here, "film-forming ability" refers to the property of forming a uniform film without repellency or other defects, and can be evaluated by methods such as spin coating on glass.

[0105] A conductive polymer (A) can be obtained, for example, by polymerizing the raw material monomers of the conductive polymer (A) in the presence of a polymerization solvent and an oxidizing agent. An example of a method for producing a conductive polymer (A) is described below. The method for producing the conductive polymer (A) of this embodiment includes a step of polymerizing the raw material monomers of the conductive polymer (A) in the presence of a polymerization solvent and an oxidizing agent (polymerization step). The method for producing the conductive polymer (A) of this embodiment may also include a step of purifying the reaction product obtained in the polymerization step (purification step).

[0106] <<Polymerization process>> The polymerization process is a process 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 raw material monomers include polymerizable monomers from which the above-mentioned monomer units are derived, and more specifically, at least one selected from the group consisting of acid group-substituted aniline, its alkali metal salts, alkaline earth metal salts, ammonium salts, and substituted ammonium salts. Examples of acid group-substituted anilines include sulfonic acid group-substituted anilines, which have a sulfonic acid group as the acid group. Typical sulfonic acid group-substituted anilines are aminobenzenesulfonic acids, specifically o-,m-,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, which are preferably used.

[0107] Examples of sulfonic acid group-substituted anilines other than aminobenzenesulfonic acids include alkyl group-substituted aminobenzenesulfonic acids such as methylaminobenzenesulfonic acid, ethylaminobenzenesulfonic acid, n-propylaminobenzenesulfonic acid, iso-propylaminobenzenesulfonic acid, n-butylaminobenzenesulfonic acid, sec-butylaminobenzenesulfonic acid, and t-butylaminobenzenesulfonic acid; alkoxy group-substituted aminobenzenesulfonic acids such as methoxyaminobenzenesulfonic acid, ethoxyaminobenzenesulfonic acid, and propoxyaminobenzenesulfonic acid; hydroxy group-substituted aminobenzenesulfonic acids; nitro group-substituted aminobenzenesulfonic acids; and halogen-substituted aminobenzenesulfonic acids such as fluoroaminobenzenesulfonic acid, chloroaminobenzenesulfonic acid, and bromoaminobenzenesulfonic acid. Among these, alkyl group-substituted aminobenzenesulfonic acids, alkoxy group-substituted aminobenzenesulfonic acids, hydroxy group-substituted aminobenzenesulfonic acids, or halogen-substituted aminobenzenesulfonic acids are preferred because they yield conductive polymers (A) with particularly excellent conductivity and solubility, and alkoxy group-substituted aminobenzenesulfonic acids, their alkali metal salts, ammonium salts, and substituted ammonium salts are particularly preferred because they are easy to manufacture. These sulfonic acid group-substituted anilines may be used individually or mixed in any proportion.

[0108] Examples of polymerization solvents include water, organic solvents, and mixed solvents of water and organic solvents. Examples of water include tap water, deionized water, purified water, and distilled water. Examples of organic solvents include alcohols such as methanol, ethanol, isopropyl alcohol, propyl alcohol, 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, 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; and pyrrolidones such as N-methylpyrrolidone and N-ethylpyrrolidone. Water or a mixed solvent of water and an organic solvent is preferred as the polymerization solvent. When a mixed solvent of water and an organic solvent is used as the polymerization solvent, the mass ratio of these solvents (water / organic solvent) is preferably 1 / 100 to 100 / 1, and more preferably 2 / 100 to 100 / 2.

[0109] As an oxidizing agent, there are no limitations as long as the standard electrode potential is 0.6V or higher, but examples include peroxodisulfates such as peroxodisulfate, ammonium peroxodisulfate, sodium peroxodisulfate, and potassium peroxodisulfate; and hydrogen peroxide. These oxidizing agents may be used individually or mixed in any proportion.

[0110] The polymerization step may involve polymerizing the starting monomers in the presence of a basic reaction aid in addition to the polymerization solvent and oxidizing agent. Examples of basic reaction aids include inorganic bases such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; ammonia; lipid amines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylmethylamine, ethyldimethylamine, and diethylmethylamine; cyclic saturated amines; and cyclic unsaturated amines such as pyridine, α-picoline, β-picoline, γ-picoline, and quinoline. Among these, inorganic bases, lipid amines, and cyclic unsaturated amines are preferred, with cyclic unsaturated amines being more preferred. These basic reaction aids may be used individually or mixed in any proportion.

[0111] Polymerization methods include, for example, adding a raw material monomer solution dropwise to an oxidizing agent solution, adding an oxidizing agent solution dropwise to a raw material monomer solution, or simultaneously adding a raw material monomer solution and an oxidizing agent solution dropwise to a reaction vessel. The raw material monomer solution may contain a basic reaction aid as needed. The polymerization solvent described above can be used as the solvent for the oxidizing agent solution and the raw material monomer solution.

[0112] The reaction temperature for the polymerization reaction is preferably 50°C or lower, more preferably -15 to 30°C, and even more preferably -10 to 20°C. If the reaction temperature for the polymerization reaction is 50°C or lower, and especially 30°C or lower, the progress of side reactions and the decrease in conductivity due to changes in the redox structure of the main chain of the resulting conductive polymer (A) can be suppressed. If the reaction temperature for the polymerization reaction is -15°C or higher, a sufficient reaction rate can be maintained and the reaction time can be shortened.

[0113] Through the polymerization process, the conductive polymer (A), which is the reaction product, is obtained in a state where it is dissolved or precipitated in the polymerization solvent. If the reaction product is dissolved in the polymerization solvent, the polymerization solvent is removed by distillation to obtain the reaction product. If the reaction product precipitates in the polymerization solvent, the polymerization solvent is filtered off using a filter such as a centrifuge to obtain the reaction product.

[0114] The reaction products may contain low molecular weight components such as unreacted starting monomers, oligomers resulting from side reactions, acidic substances (such as free acidic groups detached from the conductive polymer (A) or sulfate ions, which are decomposition products of the oxidizing agent), and basic substances (such as basic reaction aids or ammonium ions, which are decomposition products of the oxidizing agent). These low molecular weight components are impurities and can inhibit conductivity. Therefore, it is preferable to purify the reaction product to remove low molecular weight components.

[0115] <<Purification process>> The purification process is the process of purifying the reaction products obtained in the polymerization process. Any method can be used to purify the reaction product, including washing with a washing solvent, membrane filtration, ion exchange, removal of impurities by heat treatment, and neutralization precipitation. Among these, washing and ion exchange are effective from the viewpoint of easily obtaining a highly pure conductive polymer (A). Washing is particularly preferred from the viewpoint of efficiently removing raw material monomers, oligomers, and acidic substances. Ion exchange is preferred from the viewpoint of efficiently removing basic substances that exist in a state where they form salts with the acidic groups of conductive polymer (A). Washing and ion exchange may be used in combination in the purification process.

[0116] Examples of washing solvents include alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-butanol, 3-butanol, t-butanol, 1-pentanol, 3-methyl-1-butanol, 2-pentanol, n-hexanol, 4-methyl-2-pentanol, 2-ethylbutynol, benzyl alcohol, furfuryl alcohol, and tetrahydrofurfuryl alcohol; polyhydric alcohol derivatives such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methoxymethoxyethanol, propylene glycol monoethyl ether, and glyceryl 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, i.e., the conductive polymer (A) after washing, is dried, a solid conductive polymer (A) is obtained.

[0118] Ion exchange methods include column and batch processing using ion exchange resins such as cation exchange resins and anion exchange resins; and electrodialysis. If the reaction product is dissolved in the polymerization solvent, it can be brought into contact with the ion exchange resin while still dissolved. If the concentration of the reaction product is high, it may be diluted with an aqueous medium. If the reaction product precipitates in the polymerization solvent, it is preferable to filter out the polymerization solvent, dissolve the reaction product in an aqueous medium to the desired solid content concentration, and then contact the polymer solution with the ion exchange resin. When treating the reaction product after washing with ion exchange, it is preferable to dissolve the reaction product in an aqueous medium to achieve the desired solid content concentration, and then contact it with the ion exchange resin as a polymer solution. Examples of aqueous media include those similar to solvent (D) described later. From the viewpoint of industrial feasibility and purification efficiency, the concentration of conductive polymer (A) in the polymer solution is preferably 0.1 to 20% by mass, and more preferably 0.1 to 10% by mass.

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

[0120] The conductive polymer (A) after ion exchange treatment is dissolved in the polymerization solvent or aqueous medium. Therefore, if the polymerization solvent or aqueous medium is completely removed using an evaporator or the like, a solid conductive polymer (A) can be obtained. However, the conductive polymer (A) may also be used in the production of conductive compositions while still dissolved in the polymerization solvent or aqueous medium.

[0121] (Basic compound (B)) If a conductive polymer (A) has acidic groups, and the conductive composition contains a basic compound (B), it is thought that the basic compound (B) can efficiently act on the acidic groups in the conductive polymer (A), thereby increasing the stability of the conductive polymer (A). Here, efficient action on the acidic groups in the conductive polymer (A) means that stable neutralization of the conductive polymer (A) becomes possible, and a stable salt is formed between the acidic groups of the conductive polymer (A) and the basic compound (B). In other words, the conductive polymer (A) is neutralized by the basic compound (B). As a result, the destabilization of the acidic groups of the conductive polymer (A) due to hydrolysis in the conductive composition can be suppressed, and the acidic groups become less likely to detach. In addition, by forming a stable salt between the acidic groups of the conductive polymer (A) and the basic compound (B), the decomposition of the conductive polymer (A) itself can also be suppressed. Furthermore, the basic compound (B) also forms a stable salt with the decomposition products of the oxidizing agent used in the production of the conductive polymer (A) (e.g., sulfate ions). 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 pattern formation methods using ionizing radiation with chemically amplified resists, the migration of acidic substances and other materials from the conductive film to the resist layer is suppressed, thereby reducing the effects of film thinning of the resist layer.

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

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

[0124] Examples of basic compounds (b-2) include ammonia, pyridine, 4-dimethylaminopyridine, 4-dimethylaminomethylpyridine, 3,4-bis(dimethylamino)pyridine, picoline, 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 their derivatives.

[0125] In basic compounds (b-3), basic groups include, for example, basic groups defined as Arrhenius bases, Brønsted bases, Lewis bases, etc. Specifically, ammonia is an example. The hydroxyl group may be in the -OH state or in a protected state with a protecting group. Examples of protecting groups include acetyl groups; silyl groups such as trimethylsilyl group and t-butyldimethylsilyl group; acetal-type protecting groups such as methoxymethyl group, ethoxymethyl group and methoxyethoxymethyl group; benzoyl groups; and alkoxide groups. Examples of basic compounds (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 basic compounds (b-4) include sodium hydroxide, potassium hydroxide, and lithium hydroxide. These basic compounds (B) may be used individually or as a mixture of two or more in any proportion.

[0127] (Surfactant (C)) If the conductive composition contains a surfactant (C), the coatability of the conductive composition when applying it to the surface of a substrate or resist layer is improved. Examples of surfactants (C) include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. These surfactants may be used individually or mixed in any proportion.

[0128] Examples of anionic surfactants include sodium dialkyl sulfosuccinate, sodium octanoate, sodium decanoate, sodium laurate, sodium myristate, sodium palmitate, sodium stearate, perfluorononanoic acid, sodium N-lauroyl sarcosinate, sodium cocoyl glutamate, alpha-sulfo fatty acid methyl ester salts, sodium lauryl sulfate, sodium myristyl sulfate, sodium laureth sulfate, sodium polyoxyethylene alkylphenol sulfonate, ammonium lauryl sulfate, lauryl phosphate, sodium lauryl phosphate, and potassium lauryl phosphate.

[0129] Examples of cationic surfactants include tetramethylammonium chloride, tetramethylammonium hydroxide, tetrabutylammonium chloride, dodecyldimethylbenzylammonium chloride, alkyltrimethylammonium chloride, octyltrimethylammonium chloride, decyltrimethylammonium chloride, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, cetyltrimethylammonium chloride, stearyltrimethylammonium 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 cetylpyridinium chloride.

[0130] Examples of amphoteric surfactants include lauryldimethylaminoacetic acid betaine, stearyldimethylaminoacetic acid betaine, dodecylaminomethyldimethylsulfopropyl betaine, octadecylaminomethyldimethylsulfopropyl betaine, cocamidopropyl betaine, cocamidopropyl hydroxysultaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, sodium lauroyl glutamate, potassium lauroyl glutamate, lauroylmethyl-β-alanine, lauryldimethylamine-N-oxide, and oleyldimethylamine-N-oxide.

[0131] Examples of nonionic surfactants include glyceryl laurate, glyceryl monostearate, sorbitan fatty acid esters, sucrose fatty acid esters, polyoxyethylene alkyl ethers, pentaethylene glycol monododecyl ethers, octaethylene glycol monododecyl ethers, polyoxyethylene alkylphenyl ethers, octylphenol ethoxylate, nonylphenol ethoxylate, polyoxyethylene polyoxypropylene glycol, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene hexitane fatty acid esters, sorbitan fatty acid ester polyethylene glycol, lauric acid diethanolamide, oleic acid diethanolamide, stearate diethanolamide, octyl glucoside, decyl glucoside, lauryl glucoside, cetanol, stearyl alcohol, and oleyl alcohol.

[0132] In addition to those mentioned above, water-soluble polymers having nitrogen-containing functional groups and terminal hydrophobic groups may also be used as nonionic surfactants. Unlike conventional surfactants, these water-soluble polymers possess surfactant properties due to the main chain portion (hydrophilic portion) having nitrogen-containing functional groups and the terminal hydrophobic group portion, resulting in a high effect in improving coatability. Therefore, excellent coatability can be imparted to conductive compositions without the need for the use of other surfactants. Moreover, these water-soluble polymers do not contain acids or bases, and are less likely to produce by-products through hydrolysis, thus having particularly little adverse effect on resist layers and the like.

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

[0134] As a water-soluble polymer, a homopolymer of a vinyl monomer having nitrogen-containing functional groups, or a copolymer of a vinyl monomer having nitrogen-containing functional groups and a vinyl monomer without nitrogen-containing functional groups (other vinyl monomers) as the main chain structure, and a compound having hydrophobic groups in the parts other than the repeating units constituting the polymer is preferred. Examples of vinyl monomers having nitrogen-containing functional groups include acrylamide and its derivatives, and heterocyclic monomers having nitrogen-containing functional groups, among which those having an amide bond are preferred. Specifically, examples include acrylamide, N,N-dimethylacrylamide, N-isopropylacrylamide, N,N-diethylacrylamide, N,N-dimethylaminopropylacrylamide, t-butylacrylamide, diacetoneacrylamide, N,N'-methylenebisacrylamide, N-vinyl-N-methylacrylamide, N-vinylpyrrolidone, and N-vinylcaprolactam. Among these, acrylamide, N-vinylpyrrolidone, and N-vinylcaprolactam are particularly preferred from the viewpoint of solubility. Other vinyl monomers are not particularly limited as long as they can copolymerize with vinyl monomers having nitrogen-containing functional groups, but examples include styrene, acrylic acid, vinyl acetate, and long-chain α-olefins.

[0135] There are no particular limitations on the method for introducing terminal hydrophobic groups into water-soluble polymers, but it is generally simpler and preferable to introduce them by selecting a chain transfer agent during vinyl polymerization. In this case, the chain transfer agent is not particularly limited as long as it contains hydrophobic groups such as alkyl groups, aralkyl groups, aryl groups, alkylthio groups, aralkylthio groups, and arylthio groups, and these groups are introduced to the ends of the resulting polymer. For example, when obtaining a water-soluble polymer having an alkylthio group, an aralkylthio group, or an arylthio group as a terminal hydrophobic group, it is preferable to perform vinyl polymerization using a chain transfer agent having a hydrophobic group corresponding to these terminal hydrophobic groups, specifically thiols, disulfides, thioethers, etc. Examples of such chain transfer agents include n-dodecyl mercaptan, t-dodecyl mercaptan, n-octyl mercaptan, 2-ethylhexyl mercaptan, and n-octadecyl mercaptan. These may be used individually or in combination of two or more.

[0136] For use as a polymerization initiator during vinyl polymerization, azobismethylbutyronitrile or a polymerization initiator having terminal hydrophobic groups can be used. Polymerization initiators having terminal hydrophobic groups include those having a linear or branched alkyl group with 6 to 20 carbon atoms and lacking cyano and hydroxyl groups. Specifically, examples include dilauroyl peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t-hexyl peroxide, di(2-ethylhexyl)peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, and di(3,5,5-trimethylhexanoyl)peroxide. These may be used individually or in combination of two or more.

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

[0138] The mass-average molecular weight of the water-soluble polymer is preferably 100 to 1,000,000, more preferably 100 to 100,000, even more preferably 600 to 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 lower limit, the coatability of the conductive composition is improved. On the other hand, if the mass-average molecular weight of the water-soluble polymer is below the 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 to less than 2,000, it offers an excellent balance between practical water solubility and coatability.

[0139] As for the surfactant (C), nonionic surfactants are preferred among those mentioned above because they have less impact on the resist layer, and among them, water-soluble polymers having nitrogen-containing functional groups and terminal hydrophobic groups are particularly preferred.

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

[0141] (optional ingredient) Optional components include, for example, polymer compounds (excluding conductive polymers (A), basic compounds (B), and surfactants (C)), and additives. Examples of polymer compounds include polyvinyl alcohol derivatives such as polyvinyl formal and polyvinyl butyral and their modified forms, starch and its modified forms (oxidized starch, phosphate-esterified starch, cationized starch, etc.), cellulose derivatives (carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, hydroxyethylcellulose, and their salts, etc.), polyacrylamide, poly(Nt-butylacrylamide), polyacrylamide methylpropanesulfonic acid and other polyacrylamides, polyvinylpyrrolidone, polyacrylic acid (salts), 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 urethane 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 additives include pigments, defoamers, UV absorbers, antioxidants, heat resistance improvers, leveling agents, anti-sagging agents, matting agents, and preservatives.

[0142] (Content) The content of 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. Furthermore, the content of conductive polymer (A) is preferably 50 to 99.9% by mass, more preferably 80 to 99.9% by mass, and even more preferably 95 to 99.9% by mass, relative to the total mass of solids in the conductive composition. The solids in the conductive composition are the residue remaining after removing solvent (D) from the conductive composition. If the content of conductive polymer (A) is within the above range, the balance between the applicability of the conductive composition and the conductivity of the conductive film formed from the conductive composition is excellent.

[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 even more preferably 5 to 30 parts by mass, per 100 parts by mass of the conductive polymer (A). If the content of the basic compound (B) is above the lower limit, even if the conductive polymer (A) contains acidic groups, it can sufficiently form salts with the acidic groups of the conductive polymer (A) and the oxidizing agent, making it difficult for the acidic groups to detach. In addition, the basic compound (B) also sufficiently forms salts with the decomposition products of the oxidizing agent. Therefore, the migration of acidic groups and decomposition products of the oxidizing agent to the resist layer is suppressed, and film thinning of the resist layer can be suppressed. If the content of the basic compound (B) is below the upper limit, the content of the conductive polymer (A) in the conductive composition can be sufficiently secured, so a conductive film with good conductivity can be formed. Furthermore, if the conductive polymer (A) contains acidic groups, these acidic groups exist in an appropriate amount in a free state in the conductive film without forming salts with the basic compound (B), so good conductivity can be 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, and more preferably 0.1 to 0.9 mol equivalent, per 1 mol of units constituting the conductive polymer (A) that have an acidic group, from the viewpoint of further improving the coatability of the conductive composition. Furthermore, from the viewpoint of excellent retention of performance as a conductive film and further stabilizing the acidic groups in the conductive polymer (A), 0.25 to 0.85 mol equivalent is particularly preferred.

[0144] The content of surfactant (C) is preferably 5 to 200 parts by mass, and more preferably 10 to 100 parts by mass, per 100 parts by mass of conductive polymer (A). If the content of surfactant (C) is within the above range, the coatability of the conductive composition to the resist layer is further improved.

[0145] The content of solvent (D) is preferably 1 to 99% by mass, more preferably 10 to 98% by mass, and even more preferably 50 to 98% by mass, relative to the total mass of the conductive composition. If the content of solvent (D) is within the above range, the coating properties will be further improved. Furthermore, when conductive polymer (A) is used in a state in which it has been purified or dispersed or dissolved in an aqueous medium (hereinafter, conductive polymer (A) in this state is also referred to as "conductive polymer solution"), the aqueous medium derived from the conductive polymer solution is also included in the content of solvent (D) in the conductive composition. Furthermore, the total amount of all components constituting the conductive composition shall not exceed 100% by mass.

[0146] (Method for manufacturing conductive compositions) A conductive composition can be obtained, for example, by mixing the conductive polymer (A) and solvent (D) described above with, optionally, one or more basic compounds (B), surfactants (C), and other optional components. For example, since the conductive polymer (A) produced by the above-described method for producing conductive polymer (A) is in a solid state after washing, a conductive composition can be prepared by mixing the solid conductive polymer (A) and solvent (D) with a basic compound (B), a surfactant (C), and one or more optional components as needed. Furthermore, when using conductive polymer (A) that has been further purified by ion exchange after washing, the conductive polymer (A) after ion exchange treatment is obtained in the form of a conductive polymer solution, as described above. Therefore, this conductive polymer solution may be used as is as a conductive composition, or it may be diluted with solvent (D). Alternatively, a basic compound (B), a surfactant (C), and one or more optional components may be added to the conductive polymer solution as needed to form a conductive composition, or it may be further diluted with solvent (D).

[0147] <Effects and Effects> The conductive film manufacturing method of the present invention, as described above, involves irradiating the conductive film with a laser of a wavelength such that the extinction coefficient k of the conductive film is 0.2 or less to inspect for defects in the conductive film. As a result, the conductive film does not easily absorb the laser, making it easier to detect defects if they exist, and thus providing high detection accuracy. Therefore, the conductive film manufacturing method of the present invention can provide high-quality conductive films and substrates with conductive films.

[0148] <Application> The present invention's method for manufacturing conductive films can be applied, for example, to the manufacturing of conductive film-coated mask blanks, the manufacturing of masks, and the manufacturing of semiconductor devices.

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

[0150] First, a mask blank is used as the 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 film formation process described above. Furthermore, it is preferable to form a resist layer on the mask blank before forming the conductive film on the mask blank. That is, it is preferable to form the conductive film on the resist layer of a mask blank on which a resist layer has been formed. The method for forming the resist layer is the same as the resist layer formation step described above.

[0151] As mask blanks, any known type can be used, and one should be selected according to the desired mask configuration. A specific example of a mask blank is one comprising a light-transmitting substrate and a thin film provided on the light-transmitting substrate. Examples of light-transmitting substrates include soda-lime glass, low-expansion glass, and quartz glass. Examples of thin films include light-shielding films, anti-reflective films, phase-shift films, and anti-oxidation films. Thin films 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 a laser to inspect for defects. The defect inspection method is the same as the inspection process described above. Furthermore, it is preferable to determine the wavelength of the laser to irradiate the mask blanks based on the extinction coefficient k of the conductive film before inspecting for defects in the mask blanks.

[0153] The method for manufacturing conductive film-coated mask blanks according to this embodiment, as described above, involves irradiating the mask blank with a laser of a wavelength such that the extinction coefficient k of the conductive film is 0.2 or less, and inspecting the mask blank for defects. As a result, the conductive film does not easily absorb the laser, making it easier to detect defects if they exist in the mask blank, and thus the detection accuracy is high. Therefore, the method for manufacturing conductive film-coated mask blanks according to this embodiment can provide high-quality conductive film-coated mask blanks.

[0154] [Mask manufacturing method] One embodiment of the method for manufacturing the mask of the present invention will be described. The mask manufacturing method of this embodiment includes the steps of manufacturing a conductive film-coated mask blank and manufacturing a mask using the obtained conductive film-coated mask blank. Specifically, it is as follows:

[0155] First, a conductive film-coated mask blank is manufactured. For example, a conductive film-coated mask blank may be manufactured by forming a conductive film on a mask blank using the conductive film manufacturing method of the present invention described above, or a conductive film-coated mask blank may be manufactured using the conductive film-coated mask blank manufacturing method described above. Furthermore, it is preferable to form a resist layer on the mask blank before forming the conductive film on the mask blank. In other words, it is preferable to manufacture a mask using a conductive film-coated mask blank in which the resist layer and the conductive film are formed in that order. The conductive film-coated mask blanks obtained in this manner have been inspected for defects in the mask blanks.

[0156] Next, a mask is manufactured using a conductive film-coated mask blank that has undergone defect inspection, i.e., a mask blank that has passed the defect inspection. The mask manufacturing process includes, for example, the following steps: ionizing radiation irradiation, washing and developing, etching, and resist layer removal.

[0157] The ionizing radiation irradiation process involves irradiating the resist layer of a conductive film-coated mask blank with ionizing radiation in a patterned manner. Specifically, the conductive film-coated mask blank is irradiated with ionizing radiation from the conductive film side. Ionizing radiation includes charged particle beams such as electron beams and ion beams; and electromagnetic waves such as X-rays and gamma rays. The ionizing radiation irradiation process forms a latent image in the resist layer between the mask blanks and the conductive film. If the resist layer consists of a chemically amplified resist, acid is generated from the acid generator in the ionizing radiation irradiation area. In this case, since a conductive film is provided on the surface of the resist layer, grounding can be achieved from the conductive film, preventing the entire mask blank with the conductive film from becoming charged. Therefore, the displacement of electrons incident on the resist layer due to the effects of charging can be suppressed, and a latent image corresponding to the desired resist pattern can be formed with high precision.

[0158] The washing and developing process involves removing the conductive film by washing with water and developing the resist layer to form a resist pattern. Since the conductive film is water-soluble, washing with water will dissolve and remove the conductive film. Washing with water refers to contact with an aqueous solution. Examples of aqueous solutions include plain 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 a positive-type resist layer is developed, the areas of the positive-type resist layer irradiated with ionizing radiation are dissolved and removed, forming a resist pattern consisting of the areas of the positive-type resist layer that have not been irradiated with ionizing radiation. On the other hand, when a negative-type resist layer is developed, contrary to the case of a positive-type resist layer, the areas not irradiated with ionizing radiation are dissolved and removed, forming a resist pattern consisting of the irradiated areas of the negative-type resist layer.

[0160] The washing and developing process can be carried out, for example, by the following methods (α) or (β). Method (α): An alkaline developer is used for washing with water to remove the conductive film and develop the resist layer. Method (β): 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 method (α) is not particularly limited, and any known one can be used. For example, an aqueous solution of tetramethylammonium hydroxide can be used. The washing in method (β) can be carried out using an aqueous solution that is not a developer, such as water. Development can be carried out using an alkaline developer, as in method (α).

[0162] Furthermore, after the washing and developing process, the substrate may be rinsed with pure water or the like, if necessary. After the washing and developing process, or after the rinsing process, the substrate on which the resist pattern has been formed may be heated (post-baked) as needed.

[0163] The etching process involves etching a thin film of the mask blank using the resist pattern as a mask. Etching removes the thin film from areas not masked by the resist pattern (i.e., exposed areas). While known etching methods can be employed, examples include dry etching and wet etching.

[0164] The resist removal process is the process of removing the resist pattern remaining on the mask blank after etching. By removing the resist pattern, a mask (photomask) with the pattern formed on it is obtained. A known stripping agent can be used to remove the resist pattern.

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

[0166] There are no particular restrictions on the wavelength of the laser used in the second inspection process. Defects on the mask blank after the conductive film has been removed are detected specifically as follows: First, the mask blank is irradiated with a laser. If a resist layer remains on the mask blank, the resist layer is then irradiated with the laser. If defects exist on the mask blank after the conductive film has been removed, the laser light hitting the defect will scatter. By detecting this scattered laser light with a detector, defects on the mask blank after the conductive film has been removed, i.e., defects on the substrate, can be detected.

[0167] The mask manufacturing method of the present invention described above uses conductive film-coated mask blanks obtained by the conductive film-coated mask blank manufacturing method of the present invention described above, thus enabling high defect detection accuracy and providing high-quality masks.

[0168] [Manufacturing method for semiconductor devices] One embodiment of the method for manufacturing a semiconductor device according to the present invention will be described. The semiconductor device manufacturing method of this embodiment includes the steps of forming a conductive film on a substrate using the conductive film manufacturing method of the present invention described above to obtain a laminate, and manufacturing a semiconductor device using the laminate. Specifically, it is as follows:

[0169] First, a conductive film is formed on the substrate to obtain a laminate. The method for forming the conductive film is the same as the film formation process described above. Furthermore, it is preferable to form a resist layer on the substrate before forming the conductive film on the substrate. That is, it is preferable to use a substrate with a resist layer, form a conductive film on the resist layer of the substrate with a resist layer, and then manufacture a semiconductor device using a laminate in which the resist layer and conductive film are formed in this order on the substrate. The method for forming the resist layer is the same as the resist layer formation process described above. As the substrate, known materials used as substrates for semiconductor devices can be used. For example, silicon wafers can be used.

[0170] Next, after forming a conductive film on the substrate, the conductive film formed on the substrate is irradiated with a laser to inspect for defects in the mask blanks. The method for inspecting defects is the same as the inspection process described above. Furthermore, it is preferable to determine the wavelength of the laser irradiated onto the mask blanks based on the extinction coefficient k of the conductive film before inspecting for defects in the conductive film. The resulting laminate has been inspected for defects in the mask blank.

[0171] Next, a semiconductor device is manufactured using a laminate that has undergone defect inspection, i.e., a laminate that has passed the defect inspection of the mask blanks. The semiconductor device manufacturing process includes, for example, the ionizing radiation irradiation process shown below. It also further includes, if necessary, the washing process, developing process, etching process, and resist layer removal process shown below.

[0172] The ionizing radiation irradiation process involves irradiating a laminate with ionizing radiation, such as electron beams or ion beams, to form a wiring pattern. In this case, since a conductive film is provided on the surface of the substrate or resist layer, grounding can be achieved from the conductive film, preventing the entire laminate from becoming charged. Therefore, the displacement of electrons incident on the substrate or resist layer due to the effects of charging can be suppressed, and a latent image corresponding to the transferred pattern can be formed with high accuracy.

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

[0174] The semiconductor device manufacturing method 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 the "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 washing step and the developing step, between the developing step and the etching step, between the etching step and the resist removal step, or after the resist removal step.

[0175] The method for manufacturing a semiconductor device of the present invention described above irradiates a conductive film with a laser having a wavelength at which the attenuation coefficient k of the conductive film is 0.2 or less to inspect defects in the conductive film. Therefore, the conductive film is less likely to absorb the laser, and when there are defects in the conductive film, it is easy to detect the defects and the detection accuracy is high. Thus, according to the method for manufacturing a semiconductor device of the present invention, a high-quality semiconductor device can be provided.

[0176] [Examples of attenuation coefficient] Table 1 shows the attenuation coefficients at specific wavelengths of a 30-nm conductive film containing polyaniline sulfonic acid measured by an ultraviolet-visible spectrophotometer. It is considered that if the attenuation coefficient of the conductive film is 0.20 or less, the absorption of the laser is suppressed and defects are easily detected.

[0177] [Table 1] [Explanation of symbols]

[0178] 1, layer 2 laminate 11 substrate 12 conductive film 13 resist layer

Claims

1. An inspection process in which a laser is irradiated onto a conductive film to inspect for defects in the conductive film. Includes, A method for manufacturing a conductive film, wherein in the inspection step, the conductive film is irradiated with a laser having a wavelength such that the extinction coefficient k of the conductive film is 0.2 or less.

2. Film formation step of forming the conductive film on the substrate A method for producing a conductive film according to claim 1, further comprising the above.

3. A resist layer is formed on the substrate, The method for manufacturing a conductive film according to claim 2, wherein the film formation step is a step of forming the conductive film on the resist layer.

4. A determination step in which the wavelength of the laser irradiated onto the conductive film is determined based on the extinction coefficient k of the conductive film. A method for producing a conductive film according to claim 1, further comprising:

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

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

7. A method for producing a conductive film according to any one of claims 1 to 4, wherein the conductive film comprises a conductive polymer having at least one unit selected from the group consisting of units represented by the following formulas (1) to (4). 【Chemistry 1】 【Chemistry 2】 【Transformation 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 hydroxy 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. However, R in equation (1) １ and R ２ At least one of the R values ​​in equation (2) ３ ~R ６ At least one of the R in equation (3) ７ ~R １０ At least one of the following, and R of formula (4) １１ ~R １５ At least one of them is an acidic group or a salt thereof.

8. A method for producing a conductive film according to any one of claims 1 to 4, wherein the conductive film comprises a conductive polymer having a unit represented by the following formula (4). 【Transformation 5】 In formula (4), R １１ ~R １５ Each of these independently comprises 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 its salt, a hydroxyl group, a nitro group, a halogen atom, and -N(R). １６ ) ２ ,-NHCOR １６ , -SR １６ , -OCOR １６ , -COOR １６ , -COR １６ R represents -CHO or -CN. １６ This 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. However, R in equation (4) １１ ~R １５ At least one of them is an acidic group or a salt thereof.

9. A method for producing a conductive film according to any one of claims 1 to 4, wherein the conductive film comprises a conductive polymer and at least one selected from the group consisting of basic compounds and surfactants.

10. A method for producing a conductive film according to any one of claims 1 to 4, wherein the conductive film comprises a conductive polymer having at least one unit selected from the group consisting of units represented by the following formulas (1) to (4), and at least one selected from the group consisting of basic compounds and surfactants. 【Transformation 6】 【Transformation 7】 【Transformation 8】 【Chemistry 9】 In formulas (1) to (4), X represents a sulfur atom or a nitrogen atom, and R １ ~R １５ Each of these independently comprises 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 its salt, a hydroxyl group, a nitro group, a halogen atom, and -N(R). １６ ) ２ ,-NHCOR １６ , -SR １６ , -OCOR １６ , -COOR １６ , -COR １６ R represents -CHO or -CN. １６ This 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. However, R in equation (1) １ and R ２ At least one of the R values ​​in equation (2) ３ ~R ６ At least one of the R in equation (3) ７ ~R １０ At least one of the following, and R of formula (4) １１ ~R １５ At least one of them is an acidic group or a salt thereof.

11. A method for manufacturing a conductive film according to any one of claims 1 to 4, wherein the thickness of the conductive film is 1 to 100 nm.

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

13. A step of manufacturing a mask blank with a conductive film using the method for manufacturing a conductive film described in claim 2 or 3, A process for manufacturing a mask using the obtained conductive film-coated mask blanks and A method for manufacturing masks, including the method described above.

14. A process of inspecting defects on the mask blank, which is the base material, by laser irradiation after removing the conductive film from the conductive film-coated mask blank. A method for manufacturing a mask according to claim 13, further comprising:

15. A step of forming the conductive film on the substrate using the method for manufacturing a conductive film according to claim 2 or 3 to obtain a laminate, A process for manufacturing a semiconductor device using the aforementioned laminate, A method for manufacturing semiconductor devices, including [the specified element].

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

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

18. The conductive film is the object of measurement. A laser irradiation section with a wavelength such that the extinction coefficient k of the conductive film is 0.2 or less, An inspection unit that analyzes the presence or absence of defects based on scattered light from the conductive film. A defect inspection device equipped with the following features.

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