Method for forming resist pattern

Abstract

To provide a resist patterning method, a light irradiation device and a substrate treatment device capable of forming a resist pattern having high thermostability in a short time.SOLUTION: A first embodiment of the present invention is a resist patterning method. The resist patterning method is a method that exposes a resist film formed on a substrate using a resist composition, and then cures a pre-pattern, which is formed by patterning, by development. The resist pattern forming method includes a first step of arranging an optical filter which attenuates light in a region below 330 nm in wavelength, to face a light source and irradiating the pre-pattern with light having a region below 330 nm in wavelength attenuated in ultraviolet rays and visible rays. The resist patterning method includes a second step of removing the optical filter from the light source to irradiate the pre-pattern with light including both the ultraviolet rays and visible rays after the first step.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a method for forming a resist pattern. By law Regarding. [Background technology]

[0002] A method is known in which a resist film is formed on a substrate using a resist material such as a resin, the resist film is exposed, and a resist pattern of a predetermined shape is formed on the resist film by development. For example, Patent Document 1 discloses a method for forming a resist pattern, which includes a step (1) of exposing a resist film formed on a substrate using a resist composition, and then patterning the resist film by development to form a prepattern, and a step (2) of curing the prepattern by irradiating one or both of ultraviolet light and visible light. Step (2) includes an operation of irradiating the prepattern with ultraviolet light and visible light with wavelengths of less than 300 nm cut off. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-57633 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is room for improvement in forming a resist pattern having excellent heat resistance in a short period of time.

[0005] In view of the above circumstances, the present invention provides a method for forming a resist pattern that is capable of forming a resist pattern having excellent heat resistance in a short period of time. Law The purpose is to provide. [Means for solving the problem]

[0006] A first aspect of the present invention is a method for forming a resist pattern. The method for forming a resist pattern includes the following steps: Positive type containing phenolic resin and quinone diazide compoundThis method involves exposing a resist film formed on a substrate using a resist composition, and then developing the resist film to form a patterned prepattern, which is then cured. The resist pattern forming method includes a first step of arranging an optical filter that attenuates light in a wavelength range of less than 330 nm relative to a light source, and irradiating the prepattern with light in which ultraviolet light and visible light in a wavelength range of less than 330 nm has been attenuated. After the first step, the resist pattern forming method includes a second step of removing the optical filter from the light source, and irradiating the prepattern with light including both ultraviolet light and visible light.

[0007] A second aspect of the present invention is a method for forming a resist pattern. The method for forming a resist pattern includes the following steps: Positive type containing phenolic resin and quinone diazide compound This method involves exposing a resist film formed on a substrate using a resist composition, and then developing the resist film to form a patterned prepattern, which is then cured. The resist pattern forming method includes a first step of irradiating the prepattern with light in which the ultraviolet and visible light in the wavelength range of less than 330 nm is attenuated, using a first light source that emits light in which the ultraviolet and visible light in the wavelength range of less than 330 nm is attenuated. After the first step, the resist pattern forming method includes a second step of irradiating the prepattern with light including both ultraviolet and visible light, using a second light source different from the first light source. Effect of the Invention

[0011] According to the present invention, it is possible to provide a resist pattern forming method, a light irradiation apparatus, and a substrate processing apparatus that are capable of forming a resist pattern having excellent heat resistance in a short period of time. [Brief description of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view of a light irradiation device used in a method for forming a resist pattern according to a first embodiment. [Diagram 2] 4 is an example of a spectrum of light used in a first irradiation step of the first embodiment. [Diagram 3] 4 is an example of a spectrum of light used in a second irradiation step of the first embodiment. [Figure 4]FIG. 2 is an explanatory diagram of a step (1) of forming a prepattern in the first embodiment. [Diagram 5] FIG. 5 is an explanatory diagram of a first irradiation step in the step (2) of curing the prepattern in the first embodiment, following FIG. 4. [Figure 6] FIG. 6 is an explanatory diagram of the second irradiation step in the above step (2), following FIG. 5. [Figure 7] FIG. 7 is an explanatory diagram of the resist pattern formed on the substrate, following FIG. 6. [Figure 8] FIG. 1 is an explanatory diagram of a resist pattern of a comparative example. [Figure 9] FIG. 4 is an explanatory diagram of the mechanism of ozone generation in a comparative example. [Figure 10] FIG. 5 is a cross-sectional view of a light irradiation device used in a method for forming a resist pattern according to a second embodiment. [Figure 11] FIG. 13 is a plan view of a substrate processing apparatus according to a third embodiment. [Figure 12] FIG. 11 is a cross-sectional view of a light irradiation device used in a method for forming a resist pattern according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, an XYZ Cartesian coordinate system is set, and the positional relationship of each member is described with reference to this XYZ Cartesian coordinate system. A specific direction in a horizontal plane is defined as the X direction, a direction perpendicular to the X direction in the horizontal plane is defined as the Y direction, and a direction perpendicular to both the X direction and the Y direction (i.e., the vertical direction) is defined as the Z direction.

[0014] First Embodiment <Method of forming resist pattern> The method for forming a resist pattern according to the first embodiment includes a step (1) of forming a prepattern by exposing a resist film formed on a substrate using a resist composition, and then developing the resist film to form a prepattern, and a step (2) of curing the prepattern by irradiating the resist film with one or both of ultraviolet light and visible light. The resist composition will be described in detail later.

[0015] <Process (1)> In step (1), a resist film formed on a support (substrate) using a resist composition is exposed to light, and then patterned by development to form a prepattern. In the present invention, the term "prepattern" refers to the resist pattern formed in step (1). The prepattern can be formed, for example, as follows.

[0016] First, a resist composition is applied onto a support using a spinner or the like, and a baking (post-applied bake (PAB)) treatment is performed, for example, at a temperature condition of 90 to 130° C., preferably for 40 to 120 seconds, more preferably for 60 to 90 seconds, to form a resist film. In this case, the thickness of the resist film is preferably about 0.5 to 2.5 μm, more preferably about 1.0 to 2.0 μm.

[0017] Next, the resist film is selectively exposed to a light source that emits ultraviolet rays, such as a low pressure mercury lamp, a high pressure mercury lamp, an ultra-high pressure mercury lamp, a xenon lamp, or the like, through a mask (mask pattern) on which a predetermined pattern is formed.

[0018] Next, the resist film after exposure is developed. The development is carried out by, for example, pouring an alkaline aqueous solution such as a 1 to 10 mass % tetramethylammonium hydroxide (TMAH) aqueous solution from one end of the support to the other end, or by spreading the solution over the entire surface of the support from a developer dropping nozzle installed at the top near the center. Then, the resist film is left to develop for about 50 to 90 seconds.

[0019] After the development process, a rinse process is preferably performed. The rinse process is performed, for example, by washing the developer remaining on the surface of the prepattern with a rinse liquid (pure water, organic solvent, etc.). After the development process or the rinse process, a heating (post-bake) process may be performed. In this manner, a prepattern can be obtained.

[0020] The support is not particularly limited, and may be a conventionally known one, such as a substrate for electronic components or a substrate on which a predetermined wiring pattern is formed. More specifically, it may be a silicon wafer, a substrate made of metal such as copper, chromium, iron, or aluminum, or a glass substrate. The material for the wiring pattern may be, for example, copper, aluminum, nickel, or gold.

[0021] The support may be one in which an inorganic and / or organic film is provided on the above-mentioned substrate. Examples of inorganic films include inorganic anti-reflective films (inorganic BARC). Examples of organic films include organic anti-reflective films (organic BARC) and organic films such as lower organic films in multi-layer resist methods. Here, the multi-layer resist method is a method in which at least one organic film (lower organic film) and at least one resist film (upper resist film) are provided on a substrate, and the lower organic film is patterned using the resist pattern formed on the upper resist film as a mask, and it is said that a pattern with a high aspect ratio can be formed. That is, according to the multi-layer resist method, the required thickness can be secured by the lower organic film, so that the resist film can be made thin, and a fine pattern with a high aspect ratio can be formed. Multilayer resist methods are basically divided into a method using a two-layer structure consisting of an upper resist film and a lower organic film (two-layer resist method), and a method using a three-layer structure consisting of three or more layers with one or more intermediate layers (such as a thin metal film) provided between the upper resist film and the lower organic film (three-layer resist method).

[0022] The exposure can be performed using radiation such as g-rays, h-rays, i-rays, etc., without any particular limitation. As the radiation, a single light of g-rays, h-rays, or i-rays, or a mixed light of any two or more of these, can be used. By using a mixed light, the exposure time can be shortened. The spectral intensity of each light can be appropriately selected depending on the type of substrate, etc.

[0023] The development process is not limited to alkaline development, and may be solvent development using a developer containing an organic solvent (organic developer), and may be selected according to the resist composition. An example of the alkaline developer used in the alkaline development process is a 0.1 to 10 mass% aqueous solution of tetramethylammonium hydroxide (TMAH). The organic solvent contained in the organic developer used in the solvent development process may be any organic solvent that can dissolve the base material components in the resist composition, and may be appropriately selected from known organic solvents. Specifically, examples of the organic solvent include polar solvents such as ketone solvents, ester solvents, alcohol solvents, nitrile solvents, amide solvents, and ether solvents, and hydrocarbon solvents.

[0024] <Process (2)> In step (2), the prepattern is cured by irradiating it with one or both of ultraviolet light and visible light. Here, "ultraviolet light" means light with a wavelength range of about 1 nm at the lower limit and about 760 to 830 nm at the short wavelength end of visible light, and "visible light" means light with a wavelength range of about 360 to 400 nm at the lower limit and about 760 to 830 nm at the upper limit. Step (2) includes a first irradiation step of irradiating the prepattern with ultraviolet light and visible light with attenuated wavelengths in the range of less than 330 nm, and a second irradiation step of irradiating the prepattern with light including both ultraviolet light and visible light after the first irradiation step.

[0025] <Light irradiation device> FIG. 1 is a cross-sectional view of a light irradiation device 1 used in the method for forming a resist pattern of the first embodiment. For example, the light irradiation device 1 is used in step (2) in the method for forming a resist pattern of the first embodiment. As shown in FIG. 1, the light irradiation device 1 includes a light irradiation unit 3 that irradiates one or both of ultraviolet light and visible light to a substrate 2, and a control unit 4 that controls the light irradiation unit 3. The control unit 4 performs a first irradiation control in which the substrate 2 is irradiated with light in which the ultraviolet light and visible light in the region of wavelengths less than 330 nm are attenuated, and a second irradiation control in which the substrate 2 is irradiated with light including both ultraviolet light and visible light after the first irradiation control. Here, the first irradiation control is a control for performing a first irradiation step, and the second irradiation control is a control for performing a second irradiation step.

[0026] The light irradiation unit 3 includes a light source 10, an optical filter 11 that attenuates light in a wavelength range less than 330 nm, and an attachment / detachment mechanism 12 that attaches and detaches the optical filter 11 to and from the light source 10. Examples of light sources that irradiate one or both of ultraviolet light and visible light include metal halide lamps, high-pressure mercury lamps, low-pressure mercury lamps, and LED lamps. The optical filter 11 is detachably attached to the lower surface of the light source 10. For example, the attachment / detachment mechanism 12 may be a robot mechanism that includes a robot hand that can hold the optical filter 11 and a robot arm that can move the robot hand.

[0027] The light irradiation device 1 further includes a chamber 20, a substrate heating unit 30, a substrate support unit 31, a substrate adsorption unit 32, an irradiation window 40, a window support unit 41, a light source support unit 42, a shutter opening / closing unit 43, a gas supply unit 50, and a heat exhaust unit 51. The control unit 4 controls the components of the light irradiation device 1.

[0028] An accommodation space 19 capable of accommodating a substrate 2 is formed inside the chamber 20. The chamber 20 includes an upper structure 21 formed in a box shape opening downward, and a lower structure 22 connected to a lower portion of the upper structure 21.

[0029] The upper structure 21 includes a plate-shaped top plate 21a and a frame-shaped peripheral wall 21b connected to the outer periphery of the top plate 21a. The lower structure 22 is formed in a frame shape that opens in the vertical direction. The outer periphery of the lower structure 22 is connected to the lower end of the peripheral wall 21b of the upper structure 21. The lower structure 22 is provided with a line (gas supply pipe 50a) for supplying an inert gas into the chamber 20.

[0030] The substrate heating section 30 is provided within the opening of the lower structure 22. The substrate heating section 30 is connected to the lower surface of the lower structure 22 via an overhanging section that overhangs outward from the lower end. The substrate heating section 30 is capable of supporting the substrate 2 from below. The upper surface of the substrate heating section 30 is formed in a flat shape that fits along the lower surface of the substrate 2. For example, the substrate heating section 30 may include a heat source such as a hot plate.

[0031] The substrate support part 31 is built into the substrate heating part 30. The substrate support part 31 has at its upper part a substrate gripping part 31a capable of gripping the substrate 2. The upper surface of the substrate gripping part 31a is exposed from the upper surface of the substrate heating part 30. The substrate support part 31 is capable of supporting the center of the lower surface of the substrate 2 by the substrate gripping part 31a.

[0032] The substrate suction section 32 is provided in the substrate heating section 30. The substrate suction section 32 has a plurality of vacuum lines 32a opening on the upper surface of the substrate heating section 30. For example, a vacuum pump (not shown) is connected to the vacuum lines 32a. The substrate suction section 32 suctions the lower surface of the substrate 2 by vacuuming.

[0033] The emission window 40 is disposed between the light source 10 and the substrate 2. The emission window 40 is formed in the shape of a plate extending horizontally. For example, the emission window 40 is formed of synthetic quartz (for example, synthetic quartz glass manufactured using silicon tetrachloride as a raw material), natural quartz (for example, fused quartz glass manufactured using natural quartz as a raw material), or the like. The emission window 40 is detachably attached to the upper surface of the window support part 41. For example, the attachment / detachment mechanism 12 may be a robot mechanism including a robot hand capable of holding the emission window 40 and a robot arm capable of moving the robot hand.

[0034] The window support part 41 is provided on the upper surface of the lower structure 22. The window support part 41 is capable of supporting the outer periphery of the emission window 40 from below. The upper surface of the window support part 41 is disposed higher than the upper surface of the substrate 2. The window support part 41 is provided with a line (gas supply piping 50a) for supplying an inert gas into the chamber 20.

[0035] The light source support part 42 is provided between the top plate 21a and the window support part 41. The outer periphery of the light source support part 42 is connected to the peripheral wall 21b. The light source support part 42 has a support opening part 42a that is larger than the outer shape of the substrate 2 when viewed from the top-bottom direction. The light source support part 42 can support the light source 10 above the substrate 2 by the support opening part 42a.

[0036] The shutter opening / closing part 43 is provided between the light source support part 42 and the window support part 41. The shutter opening / closing part 43 is connected to the chamber 20 via a drive mechanism (not shown) or the like. The shutter opening / closing part 43 is movable between a shielding position (position shown in FIG. 1) where the light source 10 is shielded and an exposing position (not shown) where the light source 10 is exposed.

[0037] Here, the shielding position means a position where the shutter opening / closing part 43 entirely overlaps with the light source 10 when viewed from the top-bottom direction. The exposed position means a position where the shutter opening / closing part 43 does not overlap with the light source 10 when viewed from the top-bottom direction. For example, when the shutter opening / closing part 43 is located at the shielding position, the light from the light source 10 is blocked by the shutter opening / closing part 43, and the light is not irradiated onto the substrate 2. On the other hand, when the shutter opening / closing part 43 is located at the exposed position, the light from the light source 10 is not blocked by the shutter opening / closing part 43, and the light is irradiated onto the substrate 2.

[0038] 1 shows an example in which the optical filter 11 is provided on the lower surface of the light source 10 and the shutter opening / closing unit 43 is provided below the optical filter 11, but the arrangement of the optical filter 11 and the shutter opening / closing unit 43 is not limited to the example in FIG. 1. For example, the arrangement of the optical filter 11 and the shutter opening / closing unit 43 may be reversed from the example in FIG. 1. For example, the shutter opening / closing unit 43 may be provided below the light source 10, and the optical filter 11 may be provided below the shutter opening / closing unit 43. In other words, as long as the optical filter 11 and the shutter opening / closing unit 43 are provided below the light source 10, either one may be provided on the lower surface side of the light source 10.

[0039] The gas supply unit 50 can supply an inert gas such as nitrogen (N2), helium (He), or argon (Ar) to the accommodation space 19. The gas supply unit 50 includes a gas supply pipe 50a connected to the lower structure 22 and the window support 41. Although two gas supply pipes 50a are shown in FIG. 1, the number of gas supply pipes 50a to be installed is not limited. In addition, the gas supply pipes 50a only need to be connected so as to be able to supply an inert gas to the accommodation space 19, and the connection portion of the gas supply pipes 50a is not limited.

[0040] The gas supply unit 50 can adjust the oxygen concentration in the atmosphere of the accommodation space 19. The lower the oxygen concentration (by mass) in the atmosphere of the accommodation space 19, the more preferable. Specifically, the oxygen concentration in the atmosphere of the accommodation space 19 is preferably 100 ppm or less, and more preferably 20 ppm or less. For example, by setting the oxygen concentration in this manner to a preferable upper limit or less in the atmosphere when hardening the prepattern formed on the substrate 2, the hardening of the prepattern can be facilitated.

[0041] Although not shown, a pressure adjusting unit (e.g., a vacuum pipe connected to the chamber 20) capable of adjusting the pressure inside the chamber 20 (i.e., the atmospheric pressure of the accommodation space 19) may be provided. This allows the accommodation space 19 to be adjusted to a desired pressure condition.

[0042] The heat exhaust section 51 is provided on the top plate 21a. The heat exhaust section 51 can exhaust heat within the chamber 20 (i.e., hot air in the accommodation space 19) to the outside of the chamber 20. The heat exhaust section 51 includes an exhaust pipe 51a connected to the top plate 21a. Although only one exhaust pipe 51a is shown in FIG. 1, the number of exhaust pipes 51a to be installed is not limited. In addition, the exhaust pipe 51a only needs to be connected so as to be able to exhaust hot air (gas) from the accommodation space 19, and the connection position of the exhaust pipe 51a is not limited.

[0043] <First irradiation process> Fig. 2 is an example of the spectrum of light used in the first irradiation step of the first embodiment. As shown in Fig. 2, in the first irradiation step, the prepattern is irradiated with light in which the ultraviolet and visible light in the wavelength range of less than 330 nm is attenuated. The example in Fig. 2 shows the spectrum of light in which the ultraviolet and visible light in the wavelength range of less than 330 nm is mostly cut off.

[0044] For example, in the first irradiation step, an optical filter 11 (see FIG. 1, e.g., a bandpass filter) is provided that attenuates ultraviolet rays and visible light in a wavelength range of less than 330 nm, so that the prepattern is irradiated with light in which the ultraviolet rays and visible light in a wavelength range of less than 330 nm has been attenuated. For example, in the first irradiation step, it is preferable to irradiate the prepattern with light including ultraviolet rays and visible light in a wavelength range of 350 nm to 450 nm (light in which the ultraviolet rays and visible light in a wavelength range of less than 350 nm and more than 450 nm has been attenuated).

[0045] 1, for example, the attachment / detachment mechanism 12 attaches the optical filter 11 to the lower surface of the light source 10 before the first irradiation step. As a result, in the first irradiation step, the light from the light source 10 is irradiated onto the substrate 2 via the optical filter 11, so that the prepattern on the substrate can be irradiated with light in which the ultraviolet and visible light in the wavelength range of less than 330 nm has been attenuated (see FIG. 2, preferably light including a wavelength range of 350 nm to 450 nm).

[0046] <Second irradiation process> Fig. 3 is an example of the spectrum of light used in the second irradiation step of the first embodiment. As shown in Fig. 3, in the second irradiation step, after the first irradiation step, the prepattern is irradiated with light including both ultraviolet light and visible light.

[0047] For example, as shown in Fig. 1, the attachment / detachment mechanism 12 removes the optical filter 11 from the lower surface of the light source 10 after the first irradiation step and before the second irradiation step. As a result, in the second irradiation step, the light from the light source 10 is irradiated onto the substrate 2 without passing through the optical filter 11, so that the prepattern on the substrate can be irradiated with light including both ultraviolet rays and visible light. For example, in the second irradiation step, it is preferable to irradiate the prepattern with light including ultraviolet rays and visible light in the wavelength range of 200 nm or more and 600 nm or less (see Fig. 3, light in which the ultraviolet rays and visible light in the wavelength range of less than 200 nm and more than 600 nm are attenuated).

[0048] In the second irradiation step, it is preferable to irradiate the prepattern with light in which the ultraviolet and visible light in the wavelength region less than 230 nm is attenuated. In the example of Fig. 3, the spectrum of the light in which the ultraviolet and visible light in the wavelength region less than 230 nm is attenuated is shown by a solid line, and the spectrum of the light in which the ultraviolet and visible light in the wavelength region less than 230 nm is not attenuated is shown by a dashed line.

[0049] For example, as shown in FIG. 1, after the first irradiation step and before the second irradiation step, the attachment / detachment mechanism 12 removes an irradiation window 40 (for example, a window made of synthetic quartz, hereinafter also referred to as a "synthetic quartz window") for attenuating ultraviolet rays and visible light in a wavelength range less than 330 nm from the window support part 41, and attaches an irradiation window 40 (for example, a window made of natural quartz, hereinafter also referred to as a "natural quartz window") for attenuating ultraviolet rays and visible light in a wavelength range less than 230 nm to the window support part 41. That is, the attachment / detachment mechanism 12 replaces the synthetic quartz window with a natural quartz window before the second irradiation step. As a result, in the second irradiation step, the light from the light source is irradiated onto the substrate 2 through the natural quartz window, so that the prepattern on the substrate can be irradiated with light in which ultraviolet rays and visible light in a wavelength range less than 230 nm is attenuated.

[0050] In step (2), the operation of irradiating the prepattern with light in a specific wavelength range can be performed while heating. In the present invention, the temperature condition when curing the prepattern is preferably 120° C. or less, more preferably 60 to 120° C., even more preferably 70 to 120° C., particularly preferably 80 to 120° C., and most preferably 100 to 120° C. By setting the temperature condition to the preferred upper limit or less, sublimation is less likely to occur, and equipment contamination is further suppressed. On the other hand, if the temperature is equal to or higher than the preferred lower limit, curing of the pattern is more likely to proceed. The "temperature conditions when curing the prepattern" in the present invention refers to the temperature of the prepattern itself that is heated by radiation of a hot plate or the like or light irradiation, rather than the set temperature of a heating means such as a hot plate on which a support is placed, taking into consideration the total amount of heat applied to the prepattern. The temperature of the prepattern itself can be measured, for example, by using a thermocouple.

[0051] In the present invention, in step (2), the curing of the prepattern is preferably performed in an atmosphere having a dew point of -50°C (water concentration 38.8 ppm by mass) or more and -5°C (water concentration 4000 ppm by mass) or less, more preferably in an atmosphere having a dew point of -50°C (water concentration 38.8 ppm by mass) or more and -14°C (water concentration 1791 ppm by mass) or less, and even more preferably in an atmosphere having a dew point of -40°C (water concentration 126.7 ppm by mass) or more and -20°C (water concentration 1020 ppm by mass) or less. If the dew point (water concentration) of the atmosphere in which the prepattern is cured is equal to or less than the preferred upper limit, the curing of the pattern is more likely to proceed. On the other hand, if it is equal to or more than the preferred lower limit, the workability and the like are improved (the device is easy to operate, there is a cost advantage, etc.).

[0052] In the atmosphere in which the prepattern is cured, an inert gas such as nitrogen (N2), helium (He), or argon (Ar) can be supplied as a dry gas. By supplying this inert gas, the dew point of the atmosphere can be controlled, and the moisture concentration in the atmosphere can be adjusted. In addition, in step (2), the lower the oxygen concentration (by mass) of the atmosphere in which the prepattern is cured, the more preferable, and specifically, the oxygen concentration is preferably 1000 ppm or less, and more preferably 500 ppm or less. If the oxygen concentration of the atmosphere in which the prepattern is cured is equal to or less than the preferred upper limit, the curing of the pattern is more likely to proceed.

[0053] <Other processes> The method for forming a resist pattern of the present invention may include a step other than the above steps (1) and (2). For example, after step (2), a step of subjecting the cured resist pattern to a heat treatment may be provided, and the heating temperature is preferably 100° C. or higher, more preferably 100 to 300° C. By performing this heat treatment, the resist pattern patterned into a predetermined shape is reliably cured, and excellent resistance to dry etching and the like are obtained.

[0054] (Resist composition) The resist composition that can be used in the resist pattern forming method of the present invention can be either a positive resist composition in which the exposed area is dissolved and removed to form a prepattern by exposure and development in step (1), or a negative resist composition in which the unexposed area is dissolved and removed to form a prepattern. Examples of such resist compositions include the resist compositions (r1) to (r4) exemplified below.

[0055] In the present specification and claims, "aliphatic" is a relative concept to aromatic, and is defined as a group, compound, etc. that does not have aromaticity. "Alkyl group" includes linear, branched, and cyclic monovalent saturated hydrocarbon groups, unless otherwise specified. The same applies to the alkyl group in an alkoxy group. "Alkylene group" includes linear, branched, and cyclic divalent saturated hydrocarbon groups, unless otherwise specified. "Halogenated alkyl group" is a group in which some or all of the hydrogen atoms of an alkyl group are substituted with halogen atoms, and examples of the halogen atom include fluorine, chlorine, bromine, and iodine atoms. "Fluorinated alkyl group" or "fluorinated alkylene group" refers to a group in which some or all of the hydrogen atoms of an alkyl group or alkylene group are substituted with fluorine atoms. "Constituent unit" refers to a monomer unit that constitutes a polymer compound (resin, polymer, copolymer). The term "optionally substituted" includes both the case where a hydrogen atom (-H) is replaced with a monovalent group and the case where a methylene group (-CH2-) is replaced with a divalent group. "Exposure" is a concept that includes all types of exposure to radiation.

[0056] <Resist composition (r1)> The resist composition (r1) is a positive resist composition comprising an alkali-soluble resin, a specific phenol compound as a sensitivity enhancer, and a quinone diazide ester as a photosensitive component dissolved in an organic solvent.

[0057] In the resist composition (r1), the alkali-soluble resin can be selected from any of those that can be commonly used as a film-forming material. For example, phenol resin, acrylic resin, copolymer of styrene and acrylic acid, polymer of hydroxystyrene, polyvinylphenol, poly-α-methylvinylphenol, etc., which are known as film-forming resins in positive resist compositions, can be mentioned. Among these, phenol resins are particularly preferably used, and novolak resins, which are easily dissolved in an alkaline aqueous solution without swelling and have excellent developability, are particularly suitable.

[0058] Examples of the phenol resin include condensation reaction products of phenols and aldehydes, condensation reaction products of phenols and ketones, vinylphenol polymers, isopropenylphenol polymers, and hydrogenation reaction products of these phenol resins.

[0059] Examples of the phenols in the condensation reaction product include xylenols such as phenol, m-cresol, p-cresol, o-cresol, 2,3-xylenol, 2,5-xylenol, 3,5-xylenol, and 3,4-xylenol; alkylphenols such as m-ethylphenol, p-ethylphenol, o-ethylphenol, 2,3,5-trimethylphenol, 2,3,5-triethylphenol, 4-tert-butylphenol, 3-tert-butylphenol, 2-tert-butylphenol, 2-tert-butyl-4-methylphenol, and 2-tert-butyl-5-methylphenol; Examples of the phenols include alkoxyphenols such as p-methoxyphenol, m-methoxyphenol, p-ethoxyphenol, m-ethoxyphenol, p-propoxyphenol, and m-propoxyphenol; isopropenylphenols such as o-isopropenylphenol, p-isopropenylphenol, 2-methyl-4-isopropenylphenol, and 2-ethyl-4-isopropenylphenol; arylphenols such as phenylphenol; and polyhydroxyphenols such as 4,4'-dihydroxybiphenyl, bisphenol A, resorcinol, hydroquinone, and pyrogallol. These may be used alone or in combination of two or more. Among these phenols, m-cresol, p-cresol, 2,5-xylenol, 3,5-xylenol, and 2,3,5-trimethylphenol are particularly preferred.

[0060] Examples of aldehydes in the condensation reaction product include formaldehyde, paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, butylaldehyde, trimethylacetaldehyde, acrolein, crotonaldehyde, cyclohexanealdehyde, furfural, furyl acrolein, benzaldehyde, terephthalaldehyde, phenylacetaldehyde, α-phenylpropylaldehyde, β-phenylpropylaldehyde, o-hydroxybenzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, cinnamic aldehyde, etc. These may be used alone or in combination of two or more. Among these aldehydes, formaldehyde is preferred because of its ready availability, and in order to improve heat resistance in particular, it is preferred to use a combination of hydroxybenzaldehydes and formaldehyde.

[0061] Examples of ketones in the condensation reaction product include acetone, methyl ethyl ketone, diethyl ketone, diphenyl ketone, etc. These may be used alone or in combination of two or more. Among the combinations of phenols and ketones, the combination of pyrogallol and acetone is particularly preferred.

[0062] The condensation reaction product of phenols and aldehydes or ketones can be produced by a known method in the presence of an acid catalyst. Examples of the acid catalyst that can be used include hydrochloric acid, sulfuric acid, formic acid, oxalic acid, and paratoluenesulfonic acid. The condensation reaction product thus obtained is preferably subjected to a treatment such as fractionation to remove low molecular weight regions, since it has excellent heat resistance. The treatment such as fractionation is carried out by dissolving the resin obtained by the condensation reaction in a good solvent, for example, alcohol such as methanol or ethanol; ketone such as acetone or methyl ethyl ketone; ethylene glycol monoethyl ether acetate, tetrahydrofuran, etc., and then pouring it into water to cause precipitation.

[0063] Among the above, novolak resins containing 60 mol % or more of p-cresol repeating units and 30 mol % or more of m-cresol repeating units out of all phenol repeating units, and having a polystyrene-equivalent weight average molecular weight (Mw) of 2000 to 8000, are particularly preferred. By making the p-cresol repeating units 60 mol % or more, it is possible to make it difficult for sensitivity changes to occur due to temperature unevenness during heat treatment, and by making the m-cresol repeating units 30 mol % or more, good sensitivity can be obtained.

[0064] The alkali-soluble resin may contain other phenolic repeating units such as xylenol repeating units and trimethylphenol repeating units. Particularly preferred is a two-component novolak resin consisting of 60-70 mol% p-cresol repeating units and 40-30 mol% m-cresol repeating units, and is preferably a novolak resin with a low content of low molecular weight phenols, such as a binuclear phenol (condensed molecule having two phenol nuclei) content of 10% or less by GPC (gel permeation chromatography). Binuclear phenols sublimate during pre-bake or post-bake at high temperatures (e.g., 130°C) to soil the top plate of the oven and further soil the glass substrate coated with the resist composition, thereby causing a decrease in yield, and therefore a novolak resin with a low content of binuclear phenols is preferred.

[0065] In the resist composition (r1), examples of the sensitivity enhancer include phenol compounds represented by the following general formula (I).

[0066] [ka]

[0067] [In the formula, R1 to R8 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms; R9 to R11 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; Q represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a group which bonds with R9 to form a cycloalkyl group having 3 to 6 carbon atoms, or a group represented by the following chemical formula (II):

[0068] [ka]

[0069] (In the formula, R12 and R13 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms; c represents an integer of 1 to 3); a and b represent integers of 1 to 3; d represents an integer of 0 to 3; and n represents an integer of 0 to 3.]

[0070] Examples of the sensitivity enhancer in the resist composition (r1) include tris(4-hydroxyphenyl)methane, bis(4-hydroxy-3-methylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-2,3,5-trimethylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-3-hydroxyphenylmethane, and bis(4-hydroxy-3,5-dimethylphenyl)-2-hydroxyphenylmethane. -Hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-3-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-3,4-dihydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-3,4-dihydroxyphenylmethane, bis(4-hydroxy- 2,5-dimethylphenyl)-2,4-dihydroxyphenylmethane, bis(4-hydroxyphenyl)-3-methoxy-4-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-4-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-3-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-2-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy -2-methylphenyl)-3,4-dihydroxyphenylmethane, 1-[1-(4-hydroxyphenyl)isopropyl]-4-[1,1-bis(4-hydroxyphenyl)ethyl]benzene, 1-[1-(3-methyl-4-hydroxyphenyl)isopropyl]-4-[1,1-bis(3-methyl-4-hydroxyphenyl)ethyl]benzene, 2-(2,3,4-trihydroxyphenyl)-2-(2',3',4'-trihydroxyphenyl)propane, 2-(2,4-dihydroxyphenyl)-2-(2',4'-dihydroxyphenyl)propane, 2-(4-hydroxyphenyl)-2-(4'-hydroxyphenyl)propane, 2-(3-fluoro-4-hydroxyphenyl)-2-(3'-fluoro-4'-hydroxyphenyl)propane, 2-(2,4-dihydroxyphenyl)-2-(4'-hydroxyphenyl)propane, 2-(2,3,4-trihydroxyphenyl)-2-(4'-hydroxyphenyl)propane, 2-(2,3,4-trihydroxyphenyl)-2-(4'-hydroxy-3',5'-dimethylphenyl)propane, bis(2,3,4-trihydroxyphenyl)methane, bis(2,4-dihydroxyphenyl)methane, 2,3,4-trihydroxyphenyl-4'-hydroxyphenylmethane, 1,1-di(4-hydroxyphenyl)cyclohexane, 2,4-bis[1-(4-hydroxyphenyl)isopropyl]-5-hydroxyphenol, and the like.

[0071] Among these, bis(4-hydroxy-3-methylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-2,3,5-trimethylphenyl)-2-hydroxyphenylmethane, 2,4-bis[1-(4-hydroxyphenyl)isopropyl]-5-hydroxyphenol, 1,1-di(4-hydroxyphenyl)cyclohexane, 1-[1-(4-hydroxyphenyl)isopropyl]-4-[1,1-bis(4-hydroxyphenyl)ethyl]benzene, etc. are preferred because they are particularly excellent in sensitivity improvement effect. The sensitivity improver may be used alone or in combination of two or more kinds. The content of the sensitivity improver is preferably 5 to 25 parts by mass, more preferably 10 to 20 parts by mass, based on 100 parts by mass of the alkali-soluble resin.

[0072] In the resist composition (r1), examples of the photosensitive component include a quinone diazide ester (photosensitive component 1) represented by the following general formula (III), a quinone diazide ester (photosensitive component 2) represented by the following general formula (IV), and an ester of a phenol compound represented by the above general formula (I) with a 1,2-naphthoquinone diazide-5 (or 4)-sulfonyl compound.

[0073] [ka]

[0074] [In formula (III), R14 independently represents an alkyl group having 1 to 5 carbon atoms, D independently represents a hydrogen atom or a 1,2-naphthoquinone diazide-5-sulfonyl group, at least one of Ds represents a 1,2-naphthoquinone diazide-5-sulfonyl group, and l and m independently represent 1 or 2. In formula (IV), multiple Ds independently represent a hydrogen atom or a 1,2-naphthoquinone diazide-5-sulfonyl group, at least one of Ds represents a 1,2-naphthoquinone diazide-5-sulfonyl group.]

[0075] The average esterification rate of the photosensitive component 1 is preferably 40 to 60%, and more preferably 45 to 55%. If the average esterification rate is less than 40%, the film loss after development is likely to occur, and the residual film rate is likely to be low. On the other hand, if it exceeds 60%, the sensitivity tends to be significantly inferior. As the photosensitive component 1, a quinone diazide ester of bis(2-methyl-4-hydroxy-5-cyclohexylphenyl)-3,4-dihydroxyphenylmethane with a 1,2-naphthoquinone diazide-5-sulfonyl compound is preferred, in that it is relatively inexpensive and can prepare a resist composition excellent in sensitivity, resolution, and linearity, and among these, one with an esterification rate of 50% is most preferred.

[0076] The average esterification rate of the photosensitive component 2 is preferably 50 to 70%, and more preferably 55 to 65%. By setting the average esterification rate within the above range, it is possible to achieve a good balance between suppressing the occurrence of film loss after development and improving storage stability. As the photosensitive component 2, a quinone diazide ester of 2,3,4,4'-tetrahydroxybenzophenone with a 1,2-naphthoquinone diazide-5-sulfonyl compound is preferred, in that it is very inexpensive and allows the preparation of a resist composition with excellent sensitivity, and among these, one with an esterification rate of 59% is the most preferred.

[0077] The photosensitive component may be used alone or in combination of two or more kinds. The content of the photosensitive component is preferably 15 to 40 parts by mass, more preferably 20 to 30 parts by mass, based on 100 parts by mass of the total amount of the alkali-soluble resin and the sensitivity enhancer.

[0078] In the resist composition (r1), examples of the organic solvent include ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, and 2-heptanone; polyhydric alcohols and derivatives thereof such as ethylene glycol, propylene glycol, diethylene glycol, ethylene glycol monoacetate, propylene glycol monoacetate, diethylene glycol monoacetate, or their monomethyl ethers, monoethyl ethers, monopropyl ethers, monobutyl ethers, or monophenyl ethers; cyclic ethers such as dioxane; esters such as ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate; benzene, toluene, xylene, methyl isobutyl ketone, methanol, ethanol, propanol, butanol, hexanol, cyclohexanol, methyl carbonate, ethyl carbonate, propyl carbonate, and butyl carbonate. The organic solvent may be used alone or in a mixture of two or more. Among the above, propylene glycol monomethyl ether acetate (PGMEA) is preferred because it provides the resist composition with excellent coatability and the resist film on the substrate with excellent thickness uniformity. PGMEA is preferably used as a single solvent, but it can be mixed with organic solvents other than PGMEA. Examples of such organic solvents include ethyl lactate, γ-butyrolactone, and propylene glycol monobutyl ether.

[0079] In the resist composition (r1), the total amount of the alkali-soluble resin, the sensitivity improver, and the photosensitive component is preferably 30% by mass or less, more preferably 20 to 28% by mass, based on the total mass of the composition, from the viewpoint of excellent coating property onto the support. In this case, taking into consideration the amount of the optional additives described below, the content of the organic solvent is preferably 50 to 90% by mass, more preferably 65 to 85% by mass, and even more preferably 70 to 75% by mass, based on the total mass of the composition.

[0080] In the resist composition (r1), if necessary, an ultraviolet absorber for preventing halation, such as 2,2',4,4'-tetrahydroxybenzophenone, 4-dimethylamino-2',4'-dihydroxybenzophenone, 5-amino-3-methyl-1-phenyl-4-(4-hydroxyphenylazo)pyrazole, 4-dimethylamino-4'-hydroxyazobenzene, 4-diethylamino-4'-ethoxyazobenzene, 4-diethylaminoazobenzene, curcumin, etc., can be used. In addition, in the resist composition (r1), a surfactant for preventing striation, such as Fluorad FC-430, FC431 (trade name, manufactured by Sumitomo 3M Co., Ltd.); EFTOP EF122A, EF122B, EF122C, EF126 (trade name, manufactured by Tochem Products Co., Ltd.); XR-104 (product name, manufactured by Dainippon Ink and Chemicals Co., Ltd.), BYK-310 (product name, manufactured by BYK-Chemie Japan Co., Ltd.), etc. can be used. The resist composition (r1) may further contain, as necessary, a storage stabilizer such as benzoquinone, naphthoquinone, p-toluenesulfonic acid, etc.; and, as necessary, conventional additives such as an additional resin, a plasticizer, a stabilizer, a contrast improving agent, etc.

[0081] <Resist composition (r2)> The resist composition (r2) is a positive resist composition that contains a copolymer having a repeating unit represented by the following general formula (1) and a repeating unit represented by the following general formula (2), and a photosensitive component. When a resist film formed by the resist composition (r2) is applied to, for example, a microlens, a microlens with good heat resistance and chemical resistance can be formed.

[0082] [ka]

[0083] [In formulas (1) and (2), R0 each independently represents a hydrogen atom or a methyl group. R21 represents a single bond or an alkylene group having 1 to 5 carbon atoms. R22 represents an alkyl group having 1 to 5 carbon atoms. R23 represents a monovalent organic group having thermal crosslinkability. p represents an integer of 1 to 5, q represents an integer of 0 to 4, and p+q is 5 or less. However, multiple R0s and multiple R22s in the repetition may be different from each other.]

[0084] Repeating units represented by formula (1) The repeating unit represented by the general formula (1) (hereinafter also referred to as "repeating unit (1)") is alkali-soluble. In the formula (1), R0 is preferably a methyl group. Examples of the alkylene group having 1 to 5 carbon atoms in R21 include a methylene group, an ethylene group, a propylene group, an isopropylene group, an n-butylene group, an isobutylene group, a tert-butylene group, a pentylene group, an isopentylene group, and a neopentylene group, and among these, a methylene group and an ethylene group are preferable. At least one hydroxyl group is bonded to the benzene ring of the repeating unit (1). p, which indicates the number of hydroxyl groups bonded, is an integer of 1 to 5, and is preferably 1 from the viewpoint of production. In addition, it is preferable that at least one of the bonding positions of the hydroxyl group in the benzene ring is the 4th position when the bonding position of "-C(=O)-O-R21-" is the 1st position. Furthermore, the benzene ring of the repeating unit (1) may have a linear or branched alkyl group having 1 to 5 carbon atoms bonded thereto as R22. Examples of such alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, and neopentyl groups, and industrially, methyl or ethyl is more preferred. q represents an integer of 0 to 4, and is more preferably 0.

[0085] The repeating unit (1) may be used alone or in combination of two or more kinds. In the copolymer having the repeating unit (1) and the repeating unit (2), the content of the repeating unit (1) is preferably 20 to 50 mol% based on the total repeating units constituting the copolymer. By setting the content within this range, it is easy to ensure alkali solubility during development.

[0086] Repeating units represented by formula (2) The repeating unit represented by the general formula (2) (hereinafter also referred to as "repeating unit (2)") contains a thermal crosslinking group (R23). In the formula (2), R0 is preferably a methyl group. Examples of the alkylene group having 1 to 5 carbon atoms in R21 include a methylene group, an ethylene group, a propylene group, an isopropylene group, an n-butylene group, an isobutylene group, a tert-butylene group, a pentylene group, an isopentylene group, and a neopentylene group, among which a methylene group and an ethylene group are preferable. In the formula (2), R23 represents a monovalent organic group having thermal crosslinkability (hereinafter, this organic group is referred to as a "thermal crosslinking group"). The thermal crosslinking group is a group that crosslinks by applying heat. It is preferable that R23 is an organic group containing either an epoxy group or an oxetanyl group. Among these, it is more preferable that R23 is an organic group containing an epoxy group in that it can improve the crosslinking efficiency by heat treatment.

[0087] The repeating unit (2) may be used alone or in combination of two or more kinds. In the copolymer having the repeating unit (1) and the repeating unit (2), the content of the repeating unit (2) is preferably 50 to 80 mol% based on the total of the repeating units constituting the copolymer. By making the content of the repeating unit (2) in the copolymer equal to or more than the preferred lower limit, it is possible to reduce the decrease in transmittance due to heat treatment and to easily ensure thermosetting properties, while by making the content equal to or less than the preferred upper limit, it is possible to further suppress the generation of residues during development.

[0088] The copolymer having the repeating unit (1) and the repeating unit (2) may be either randomly polymerized or block polymerized. As described above, by using a copolymer having different repeating units, repeating unit (1) and repeating unit (2), it becomes easy to control the alkali dissolution rate and heat resistance. The mass average molecular weight (Mw: measured value in terms of styrene by gel permeation chromatography (GPC)) of the copolymer is preferably 10,000 to 30,000. When the Mw of the copolymer is equal to or more than the preferred lower limit, the heat resistance is improved, and for example, when a microlens is formed using the copolymer, the lens shape can be easily maintained even during a baking treatment for hardening the microlens. On the other hand, by setting it to equal to or less than the preferred upper limit, the generation of residue during development can be suppressed. In addition, the resist composition (r2) preferably contains a copolymer having a repeating unit (1) and a repeating unit (2) and Mw of 10,000 to 30,000, and therefore can form a resist film having a high glass transition temperature and heat resistance that can maintain its shape even when exposed to high temperatures. Furthermore, the resist composition (r2) contains a copolymer having a repeating unit containing a thermal crosslinking group (R23), and therefore can form a resist film having high hardness and excellent chemical resistance.

[0089] The resist composition (r2) may contain a resin component other than the copolymer having the repeating unit (1) and the repeating unit (2) described above in combination with the copolymer, such as an acrylic resin, a hydroxystyrene resin, or a novolak resin.

[0090] The photosensitive component used in the resist composition (r2) may be the same as the photosensitive component used in the resist composition (r1) described above. The photosensitive component may be used alone or in combination of two or more. The content of the photosensitive component in the resist composition (r2) is preferably within the range of 10 to 40 mass% based on the solid content of the resist composition (r2). By making the content of the photosensitive component equal to or greater than the preferred lower limit, a pattern can be formed well. When the resist composition (r2) is used for forming a microlens, a lens shape can be formed well during development. On the other hand, by making the content of the photosensitive component equal to or less than the preferred upper limit, developability can be improved and the generation of residues during development can be suppressed.

[0091] In the resist composition (r2), components other than the copolymer having the repeating unit (1) and the repeating unit (2) and the photosensitive component can be used as necessary. In the resist composition (r2), for example, from the viewpoint of coatability on the support, a surfactant may be blended, or various additives such as a sensitizer and an antifoaming agent may be added. The resist composition (r2) can be prepared by dissolving the copolymer, the photosensitive component, and other components as necessary in an organic solvent.

[0092] <Resist composition (r3)> The resist composition (r3) is a chemically amplified negative resist composition containing an alkali-soluble resin and an acid generator. In the resist composition (r3), the alkali-soluble resin can be selected from conventionally known resins that are generally used as base resins in negative chemically amplified resist compositions, depending on the light source used for exposure. Examples include novolac resins, polyhydroxystyrene resins, and acrylic resins. The alkali-soluble resin may be a novolac resin, a polyhydroxystyrene resin, an acrylic resin, or the like, each of which may be used alone or in a mixture of two or more. When the resist composition (r3) contains an alkali-soluble resin, an acid generator, and a plasticizer described below, the content of the alkali-soluble resin is preferably 30 to 99 parts by mass, more preferably 65 to 95 parts by mass, relative to 100 parts by mass of the total solid content of the alkali-soluble resin, the acid generator, and the plasticizer.

[0093] In the resist composition (r3), the acid generator is not particularly limited as long as it is a compound that generates an acid directly or indirectly upon irradiation with light, and can be arbitrarily selected from conventionally known compounds. The acid generator may be used alone or in combination of two or more. The content of the acid generator in the resist composition (r3) is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 2 parts by mass, and even more preferably 0.1 to 1 part by mass, based on 100 parts by mass of the total solid content of the resist composition (r3).

[0094] In the resist composition (r3), components other than the alkali-soluble resin and the acid generator can be used as necessary. For example, in addition to the alkali-soluble resin and the acid generator, a plasticizer may be added. By adding a plasticizer, the occurrence of cracks can be suppressed. Examples of the plasticizer include acrylic resin and polyvinyl resin.

[0095] In addition to the alkali-soluble resin and the acid generator, or to the alkali-soluble resin, the acid generator, and the plasticizer, the resist composition (r3) may contain a crosslinking agent. Examples of such crosslinking agents include amino compounds such as melamine resins, urea resins, guanamine resins, glycoluril-formaldehyde resins, succinylamide-formaldehyde resins, and ethylene urea-formaldehyde resins. In particular, alkoxymethylated amino resins such as alkoxymethylated melamine resins and alkoxymethylated urea resins are preferably used.

[0096] In addition to the above components, the resist composition (r3) may contain a fluorine-containing polymeric compound having a structural unit containing a base dissociable group (preferably a base dissociable group containing a fluorine atom) as necessary. The "base dissociable group" is an organic group that can be dissociated by the action of a base. That is, the "base dissociable group" is dissociated by the action of an alkaline developer (for example, a 2.38 mass% TMAH aqueous solution at 23°C). When the base dissociable group is dissociated by the action of an alkaline developer, a hydrophilic group appears, and the affinity for the alkaline developer is improved. That is, the fluorine-containing polymeric compound is a highly hydrophobic "polymeric compound having a fluorine atom", but at the same time, since it also has a "base dissociable group", the affinity for the alkaline developer is improved by the action of the alkaline developer. Therefore, by using the negative resist composition, it is possible to form a resist film that is hydrophobic during immersion exposure and dissolves well in an alkaline developer during development.

[0097] In addition to the above components, the resist composition (r3) may contain, if necessary, a quencher such as a secondary or tertiary amine, e.g., triethylamine, tributylamine, dibutylamine, triethanolamine, etc.; a surfactant, a functional silane coupling agent as an adhesion promoter, a filler, a colorant, a viscosity modifier, an antifoaming agent, etc. The resist composition (r3) can be prepared by dissolving an alkali-soluble resin, an acid generator, and, if necessary, other components, in an organic solvent.

[0098] <Resist composition (r4)> The resist composition (r4) is a negative resist composition containing an alkali-soluble resin, a cationic polymerization initiator, and a sensitizer. In the resist composition (r4), the alkali-soluble resin may be a polyfunctional epoxy resin. The polyfunctional epoxy resin is not particularly limited as long as it is an epoxy resin having enough epoxy groups in one molecule to form a thick-film resist pattern, and examples of the polyfunctional epoxy resin include polyfunctional phenol novolac epoxy resin, polyfunctional orthocresol novolac epoxy resin, polyfunctional triphenyl novolac epoxy resin, and polyfunctional bisphenol A novolac epoxy resin. In addition, a photocurable alkali-soluble base material may also be used as the alkali-soluble resin.

[0099] In the resist composition (r4), the cationic polymerization initiator is a compound that generates a cationic moiety when irradiated with ultraviolet light, far ultraviolet light, an excimer laser such as KrF or ArF, X-rays, or an electron beam, and the cationic moiety can become a polymerization initiator. This cationic polymerization initiator can be arbitrarily selected from conventionally known ones. The cationic polymerization initiator may be used alone or in combination of two or more kinds. In the resist composition (r4), the content of the cationic polymerization initiator is preferably 0.5 to 20 parts by mass relative to 100 parts by mass of the alkali-soluble resin. By setting the content of the cationic polymerization initiator to 0.5 parts by mass or more, sufficient photosensitivity can be obtained. On the other hand, by setting the content to 20 parts by mass or less, the properties of the resist film are improved.

[0100] In the resist composition (r4), the sensitizer is preferably a naphthalene derivative or anthracene or a derivative thereof capable of forming a crosslink with the polyfunctional epoxy resin. The sensitizing function of such a sensitizer can further increase the sensitivity of the resist composition. Among them, it is particularly preferable to contain a sensitizer made of dihydroxynaphthalene having two hydroxyl groups or anthracene. These sensitizers have multiple aromatic rings, so that the resist pattern can be made highly hard. The sensitizers may be used alone or in combination of two or more kinds. The content of the sensitizer in the resist composition (r4) is preferably 1 to 50 parts by mass relative to 100 parts by mass of the alkali-soluble resin.

[0101] In the resist composition (r4), components other than the alkali-soluble resin, cationic polymerization initiator, and sensitizer can be used as necessary. For example, it is preferable to use an oxetane derivative from the viewpoint of further enhancing the curability of the resist pattern. Also, a photopolymerization initiator for a photosensitive resin composition other than the above-mentioned cationic polymerization initiator can be used. In addition, a photopolymerizable compound may be blended because it is less likely to cause curing defects during exposure and is easy to obtain sufficient heat resistance.

[0102] Furthermore, the resist composition (r4) may contain, if desired, compatible additives, such as conventionally known additives for improving the performance of the resist pattern, such as additional resins, plasticizers, stabilizers, colorants, coupling agents, leveling agents, etc. The resist composition (r4) may be prepared by dissolving an alkali-soluble resin, a cationic polymerization initiator, a sensitizer, and, if necessary, other components, in an organic solvent.

[0103] <Description of each step in the method for forming a resist pattern> Fig. 4 is an explanatory diagram of step (1) of forming a prepattern of the first embodiment. Fig. 5 is an explanatory diagram of a first irradiation step in step (2) of hardening the prepattern of the first embodiment, subsequent to Fig. 4. Fig. 6 is an explanatory diagram of a second irradiation step in the above step (2), subsequent to Fig. 5. Fig. 7 is an explanatory diagram of a resist pattern formed on a substrate, subsequent to Fig. 6.

[0104] As shown in Fig. 4, in step (1), a resist film formed on a substrate using a resist composition is exposed to light, and then developed and patterned to form a prepattern. Fig. 4 shows a trapezoidal prepattern. After step (1), the process proceeds to step (2).

[0105] As shown in Fig. 5, in step (2), first, in the first irradiation step, the prepattern is irradiated with light in which the ultraviolet ray and visible light in the wavelength range of less than 330 nm is attenuated (see arrow L1 in Fig. 5). For example, in the first irradiation step, an optical filter that attenuates the wavelength range of less than 330 nm is provided for the light source, so that the prepattern is irradiated with light in which the ultraviolet ray and visible light in the wavelength range of less than 330 nm is attenuated. After the first irradiation step, the process proceeds to the second irradiation step.

[0106] As shown in Fig. 6, in the second irradiation step, the prepattern is irradiated with light including both ultraviolet light and visible light (see arrow L2 in Fig. 6). For example, in the second irradiation step, the prepattern is irradiated with light including both ultraviolet light and visible light by removing an optical filter from the light source. For example, in the second irradiation step, the prepattern is irradiated with light in which the ultraviolet light and visible light in the wavelength range of less than 230 nm are attenuated by providing a natural quartz window.

[0107] As shown in Fig. 7, the prepattern is cured through the second irradiation step. This allows a resist pattern to be formed on the substrate. If necessary, the resist pattern may be subjected to a heat treatment after the second irradiation step.

[0108] <Action and effect> As described above, the resist pattern forming method of the present embodiment is a resist pattern forming method having a step (1) of exposing a resist film formed on a substrate using a resist composition, and then patterning the resist film by development to form a prepattern, and a step (2) of curing the prepattern by irradiating one or both of ultraviolet light and visible light, and the step (2) includes a first irradiation step of irradiating the prepattern with light in which the ultraviolet light and visible light in the region of wavelengths less than 330 nm are attenuated, and a second irradiation step of irradiating the prepattern with light including both ultraviolet light and visible light after the first irradiation step. For example, if the prepattern is irradiated with ultraviolet light having a wavelength of 254 nm, a cured layer may be partially formed on the surface layer of the prepattern. In this case, even if the prepattern is irradiated with ultraviolet light, it is blocked by the cured layer, and curing is difficult to progress inside the prepattern. This may result in a resist pattern in which the inside is not sufficiently cured. If the inside of the resist pattern is not sufficiently cured, there is a high possibility that wrinkle-like roughness will occur in the resist pattern during heat treatment. In addition, if ultraviolet light irradiation is simply continued to progress the curing inside the prepattern, it is highly likely that it will take a long time to form the resist pattern. In addition, when the prepattern is irradiated with ultraviolet light having a wavelength of 254 nm, the reason why a hardened layer is partially formed on the surface layer of the prepattern is considered to be that when the prepattern is irradiated with ultraviolet light having a wavelength of 254 nm with strong energy (see arrow Lx in FIG. 8), an ethylene group (-C=C-) that does not easily transmit long wavelengths is generated in the organic film, so that ultraviolet light having a wavelength of 365 nm is difficult to pass through. Therefore, it is considered that the surface layer part of the prepattern is polymerized, but the polymerization does not progress easily inside the prepattern. When a heat treatment is performed after ultraviolet light irradiation, the reason why wrinkle-like roughness occurs is considered to be due to the fact that the inside of the resist pattern is not sufficiently polymerized. In contrast, according to the present embodiment, in the first irradiation step, the prepattern is irradiated with light in which the ultraviolet light and visible light in the region of wavelengths less than 330 nm are attenuated, thereby making it possible to suppress the formation of a hardened layer partially on the surface layer of the prepattern (see FIG. 5).Therefore, in the second irradiation step after the first irradiation step, the prepattern can be irradiated with light including both ultraviolet light and visible light in a state in which the formation of a hardened layer on the surface layer of the prepattern is suppressed (see FIG. 6). As a result, in the second irradiation step, the light is suppressed from being blocked by the hardened layer (because the light is easily allowed to enter the inside of the prepattern), and hardening of the inside of the prepattern can be sufficiently advanced in a short time. Therefore, a resist pattern in which the surface layer and the inside are sufficiently hardened can be formed (see FIG. 7). As a result, it is possible to suppress the occurrence of wrinkle-like roughness or the like in the resist pattern during the heat treatment. Therefore, a resist pattern with excellent heat resistance can be formed in a short time. Incidentally, there are cases in which wiring is performed on a substrate by vapor deposition of a high melting point metal (for example, tungsten, etc.). In this case, high heat is applied to the substrate, and as a result, the resist pattern becomes high temperature (for example, a temperature of 160° C. or higher). According to the present embodiment, a resist pattern with excellent heat resistance can be formed, and therefore it can withstand high temperatures even when a high melting point metal is vapor-deposited on the substrate.

[0109] In this embodiment, the second irradiation step irradiates the prepattern with ultraviolet light and visible light with attenuated wavelengths of less than 230 nm, thereby achieving the following effects. For example, if the prepattern is irradiated with ultraviolet light and visible light with wavelengths of less than 230 nm in the second irradiation step, ozone (O3) may be generated. In this case, the hardened layer formed on the surface layer of the prepattern may be destroyed by the ozone. As described above, if the prepattern is irradiated with ultraviolet light with a wavelength of 254 nm, a hardened layer is partially formed on the surface layer of the prepattern, but at the same time, ultraviolet light with strong energy less than 230 nm generates ozone (O3) and is likely to start decomposing the formed hardened layer (see FIG. 9). At the same time, ethylene groups (-C=C-) are generated, making it difficult for ultraviolet light with a wavelength of 365 nm to pass through, and as a result, it is considered that the surface layer of the prepattern is polymerized, but not very strongly, and the polymerization inside the prepattern is difficult to proceed. In contrast, according to the present embodiment, the prepattern is irradiated with ultraviolet light and visible light with wavelengths of less than 230 nm attenuated in the second irradiation step, thereby suppressing the generation of ozone, and thus preventing the destruction of the cured layer formed on the surface layer of the prepattern.

[0110] In this embodiment, in the first irradiation step, the light source 10 is provided with an optical filter 11 that attenuates light in the wavelength range less than 330 nm, so that the prepattern is irradiated with light in which ultraviolet and visible light in the wavelength range less than 330 nm is attenuated, and in the second irradiation step, the optical filter 11 is removed from the light source 10, so that the prepattern is irradiated with light including both ultraviolet and visible light, thereby achieving the following effects: A common light source 10 can be used in the first and second irradiation steps.

[0111] In the light irradiation device 1 of this embodiment, the light irradiation section 3 includes a light source 10, an optical filter 11 that attenuates light in the wavelength range less than 330 nm, and an attachment / detachment mechanism 12 that attaches and detaches the optical filter 11 to the light source 10. In the first irradiation control, the optical filter 11 is provided on the light source 10, so that the substrate 2 is irradiated with light in which the ultraviolet rays and visible light in the wavelength range less than 330 nm is attenuated, and in the second irradiation control, the optical filter 11 is removed from the light source 10, so that the substrate 2 is irradiated with light including both ultraviolet rays and visible light.

[0112] Second Embodiment Next, a second embodiment of the present invention will be described with reference to Fig. 10. In the second embodiment, the configuration of the light irradiation unit is particularly different from that of the first embodiment. In Fig. 10, the same components as those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted. Fig. 10 is a cross-sectional view of a light irradiation device 201 used in the method for forming a resist pattern of the second embodiment.

[0113] 10, the light irradiation unit 203 includes a first light source 210A, a second light source 210B different from the first light source 210A, and an exchange mechanism 212 that exchanges the first light source 210A with the second light source 210B. For example, the first light source 210A is a light source that emits light in which the ultraviolet light and visible light in a wavelength range of less than 330 nm are attenuated. For example, the second light source 210B is a light source that emits light including both ultraviolet light and visible light (light in which the wavelength range of less than 330 nm is not attenuated). For example, the exchange mechanism 212 may be a robot mechanism that includes a robot hand that can hold the first light source 210A or the second light source 210B, and a robot arm that can move the robot hand.

[0114] For example, before the first irradiation step, the replacement mechanism 212 attaches the first light source 210A to the support opening 42a of the light source support part 42. As a result, in the first irradiation step, the light from the first light source 210A is irradiated onto the substrate 2, so that the prepattern on the substrate can be irradiated with light in which the ultraviolet ray and visible light in the wavelength range of less than 330 nm is attenuated (preferably light including a wavelength range of 350 nm or more and 450 nm or less).

[0115] For example, the replacement mechanism 212 attaches the second light source 210B to the support opening 42a of the light source support portion 42 after the first irradiation step and before the second irradiation step. That is, the replacement mechanism 212 replaces the first light source 210A with the second light source 210B before the second irradiation step. As a result, in the second irradiation step, the light from the second light source 210B is irradiated onto the substrate 2, so that the prepattern on the substrate can be irradiated with light including both ultraviolet light and visible light. For example, in the second irradiation step, it is preferable to irradiate the prepattern with light including ultraviolet light and visible light in a wavelength range of 200 nm or more and 600 nm or less (light in which the ultraviolet light and visible light in a wavelength range of less than 200 nm and more than 600 nm is attenuated).

[0116] As described above, according to this embodiment, in the first irradiation step, the first light source 210A that emits light in which the ultraviolet ray and visible ray in the wavelength range less than 330 nm is attenuated is provided, and the pre-pattern is irradiated with light in which the ultraviolet ray and visible ray in the wavelength range less than 330 nm is attenuated, and in the second irradiation step, the second light source 210B different from the first light source 210A is provided in place of the first light source 210A, and the pre-pattern is irradiated with light including both ultraviolet ray and visible ray, thereby achieving the following effects: Since it is only necessary to replace the light sources 210A and 210B between the first irradiation step and the second irradiation step, the replacement work is easier than when replacing an optical filter.

[0117] In the light irradiation device 201 of this embodiment, the light irradiation section 203 includes a first light source 210A that emits light in which the ultraviolet ray and visible light in the wavelength range less than 330 nm is attenuated, a second light source 210B that is different from the first light source 210A, and an exchange mechanism 212 that exchanges the first light source 210A and the second light source 210B. In the first irradiation control, the first light source 210A is provided so that the substrate 2 is irradiated with light in which the ultraviolet ray and visible light in the wavelength range less than 330 nm is attenuated, and in the second irradiation control, the second light source 210B is provided in place of the first light source 210A so that the substrate 2 is irradiated with light including both ultraviolet ray and visible light.

[0118] <Third embodiment> Next, a third embodiment of the present invention will be described with reference to Fig. 11. Fig. 11 is a plan view of a substrate processing apparatus 300 according to the third embodiment. In Fig. 11, the same components as those in the above-described embodiments are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

[0119] 11, the substrate processing apparatus 300 includes a coating apparatus 360 that coats a resist film containing a resist composition on the substrate 2, an exposure apparatus 361 that exposes the resist film coated on the substrate 2, a development apparatus 362 that develops and patterns the exposed resist film to form a prepattern, and a light irradiation apparatus 301 that irradiates one or both of ultraviolet light and visible light to cure the prepattern. The coating apparatus 360, the exposure apparatus 361, the development apparatus 362, and the light irradiation apparatus 301 are arranged in this order in the transport direction of the substrate 2.

[0120] The substrate processing apparatus 300 further includes a transport device 363 for transporting the substrate 2, and a control device 364 for comprehensively controlling each part of the substrate processing apparatus 300. For example, the transport device 363 may include a robot mechanism including a robot hand capable of holding the substrate 2, and a robot arm capable of moving the robot hand.

[0121] The coating device 360 ​​is a device that coats a resist film on the substrate 2. For example, the coating device 360 ​​may be a spin coating device, a non-spin coating device, a slit nozzle coating device, or the like. Note that a standby device 365 for keeping the substrate 2 on standby, a cleaning device 366 for cleaning the substrate 2, a dehydration device 367 for dehydrating the substrate 2, and the like may be provided on the -X side of the coating device 360.

[0122] The exposure device 361 is disposed on the +X side of the coating device 360. The exposure device 361 is a device that exposes a resist film coated on the substrate 2. Note that a pre-bake processing device 368 that performs a pre-bake process on the substrate 2 may be provided on the -X side of the exposure device 361.

[0123] The developing device 362 is disposed on the -X side of the exposure device 361. The developing device 362 is a device that performs a developing process on the substrate after exposure. A transport mechanism 369 such as a belt conveyor may be provided on the +X side of the developing device 362.

[0124] The light irradiation device 301 is disposed on the -X side of the developing device 362. For example, the light irradiation device 1 (see FIG. 1) of the first embodiment or the light irradiation device 201 (see FIG. 10) of the second embodiment described above can be provided as the light irradiation device 301. Note that a post-bake processing device 370 that performs a post-bake process on the substrate 2 may be provided on the -X side of the light irradiation device 301.

[0125] As described above, the substrate processing apparatus 300 of this embodiment includes the coating apparatus 360 that coats the substrate 2 with a resist film containing a resist composition, the exposure apparatus 361 that exposes the resist film coated on the substrate 2, the development apparatus 362 that develops and patterns the exposed resist film to form a prepattern, and the light irradiation apparatus 301 that irradiates one or both of ultraviolet light and visible light to harden the prepattern. According to this embodiment, by providing the light irradiation apparatus 1 (see FIG. 1) or the light irradiation apparatus 201 (see FIG. 10) described above as the light irradiation apparatus 301, a resist pattern with excellent heat resistance can be formed in a short time.

[0126] <Fourth embodiment> Next, a fourth embodiment of the present invention will be described with reference to Fig. 12. The fourth embodiment is different from the first embodiment in particular in the arrangement of the light irradiation units. In Fig. 12, the same components as those in the first embodiment are given the same reference numerals, and detailed descriptions thereof will be omitted. Fig. 12 is a cross-sectional view of a light irradiation device 401 used in the method for forming a resist pattern of the fourth embodiment.

[0127] As shown in Fig. 12, the light irradiation device 401 includes a chamber 420 and a light irradiation unit 403 provided outside the chamber 420. The chamber 420 is configured to be able to accommodate the substrate 2 in an enclosed space. A heating mechanism 430 for heating the substrate 2 is provided inside the chamber 420. The heating mechanism 430 has a rectangular plate shape having substantially the same size as the substrate 2 in a plan view. The heating mechanism 430 is disposed so as to support the substrate 2 from below. The heating mechanism 430 is attached to a stage 431. The heating mechanism 430 includes a heater (not shown) and the like.

[0128] A transmitting portion 423 capable of transmitting light from the light sources 410A and 410B is provided on the top plate of the chamber 420. For example, the transmitting portion 423 is formed of quartz, heat-resistant glass, a resin sheet, a resin film, or the like.

[0129] Below the chamber 420, a lifting mechanism 460 capable of moving the substrate 2 in the Z direction is provided. The lifting mechanism 460 has a plurality of lift pins 461 extending in the Z direction. A plurality of insertion holes that open to allow the lift pins 461 to be inserted are provided in the stage 431, the bottom plate of the chamber 420, and the heating mechanism 430. The lift pins 461 are capable of moving in the Z direction in the chamber 420 while supporting the substrate 2 accommodated in the chamber 420. In the example of FIG. 12, the tips of the plurality of lift pins 461 abut against the lower surface of the substrate 2 through the respective insertion holes, and the plurality of lift pins 461 are elevated, thereby showing a state in which the substrate 2 is separated upward from the heating mechanism 430. Note that a driving source 462 that raises and lowers the plurality of lift pins 461 in the lifting mechanism 460 is disposed outside the chamber 420.

[0130] The light irradiation unit 403 includes a first light source 410A, a second light source 410B different from the first light source 410A, and a transport mechanism 412 for moving the first light source 410A and the second light source 410B. For example, the first light source 410A is a light source that emits light in which the ultraviolet and visible light in a wavelength range less than 330 nm is attenuated. For example, the second light source 410B is a light source that emits light including both ultraviolet and visible light (light in which the wavelength range less than 330 nm is not attenuated).

[0131] The transport mechanism 412 includes a rail 413 extending in the X direction and two gate-shaped frames 414A, 414B that can slide along the rail 413. A pair of rails are provided to sandwich the chamber from both sides in the Y direction. The gate-shaped frames 414A, 414B are formed in a gate shape to straddle the chamber 420 in the Y direction. The gate-shaped frames 414A, 414B have recesses that are recessed upward to be able to hold the light sources 410A, 410B. The light sources 410A, 410B are accommodated in the recesses. The light sources 410A, 410B except for their irradiation surfaces (lower surfaces) are covered by the walls of the gate-shaped frames 414A, 414B that form the recesses.

[0132] For example, the gate-shaped frames 414A and 414B are formed of a member that blocks light from the light sources 410A and 410B. This makes it possible to prevent the light from irradiating the light from the light sources 410A and 410B from diffusing to the sides of the gate-shaped frames 414A and 414B, and to irradiate the light from the light sources 410A and 410B downward (to the substrate 2 in the chamber 420). Note that the example of FIG. 12 shows a state in which the first light source 410A held by the gate-shaped frame 414A is disposed directly above the transmission section 423.

[0133] For example, before the first irradiation step, the transport mechanism 412 moves the gate-shaped frames 414A and 414B holding the light sources 410A and 410B along the rails 413, and positions the first light source 410A directly above the transmission section 423. As a result, in the first irradiation step, the light from the first light source 410A is irradiated onto the substrate 2, so that the prepattern on the substrate can be irradiated with light in which the ultraviolet ray and visible light in the wavelength range of less than 330 nm is attenuated (preferably light including a wavelength range of 350 nm or more and 450 nm or less).

[0134] For example, after the first irradiation step and before the second irradiation step, the transport mechanism 412 moves the gate-shaped frames 414A and 414B holding the light sources 410A and 410B along the rails 413, and positions the second light source 410B directly above the transmission section 423. That is, the transport mechanism 412 positions the second light source 410B directly above the transmission section 423 before the second irradiation step. As a result, in the second irradiation step, the light from the second light source 410B is irradiated onto the substrate 2, so that the pre-pattern on the substrate can be irradiated with light including both ultraviolet light and visible light. For example, in the second irradiation step, it is preferable to irradiate the pre-pattern with light including ultraviolet light and visible light in a wavelength range of 200 nm or more and 600 nm or less (light in which the ultraviolet light and visible light in a wavelength range of less than 200 nm and more than 600 nm is attenuated).

[0135] As described above, according to this embodiment, in the first irradiation step, the first light source 410A emitting light in which the ultraviolet ray and visible light in the wavelength range less than 330 nm is attenuated is disposed directly above the transmission portion 423, thereby irradiating the pre-pattern with light in which the ultraviolet ray and visible light in the wavelength range less than 330 nm is attenuated, and in the second irradiation step, the second light source 410B different from the first light source 410A is disposed directly above the transmission portion 423, thereby irradiating the pre-pattern with light including both ultraviolet ray and visible light, thereby achieving the following effects: Since it is only necessary to move the light sources 410A and 410B between the first irradiation step and the second irradiation step, the work is easier than when replacing an optical filter.

[0136] In the light irradiation device 401 of this embodiment, the light irradiation section 403 includes a first light source 410A that emits light in which the ultraviolet ray and visible light in the wavelength range less than 330 nm is attenuated, a second light source 410B that is different from the first light source 410A, and a transport mechanism 412 that moves the first light source 410A and the second light source 410B. In the first irradiation control, the first light source 410A is positioned directly above the transmission section 423 to irradiate the substrate 2 with light in which the ultraviolet ray and visible light in the wavelength range less than 330 nm is attenuated, and in the second irradiation control, the second light source 410B is positioned directly above the transmission section 423 to irradiate the substrate 2 with light including both ultraviolet ray and visible light.

[0137] <Modification> The shapes and combinations of the components shown in the above-mentioned examples are merely examples, and can be modified in various ways based on design requirements. For example, the present invention may be applied to a substrate processing system including the light irradiation device or substrate processing device of the above-mentioned embodiment. For example, the substrate processing system is a system that is incorporated into a manufacturing line such as a factory and used to form a thin film on a predetermined area of ​​a substrate. Although not shown, for example, the substrate processing system includes a substrate processing unit including the light irradiation device or substrate processing device, a substrate carry-in unit that is a unit to which a carry-in cassette containing a substrate before processing is supplied and an empty carry-in cassette is collected, a substrate unloading unit that is a unit to which an unloading cassette containing a substrate after processing is collected and an empty unloading cassette is supplied, a transport unit that transports the carry-in cassette between the substrate processing unit and the substrate carry-in unit and transports the unloading cassette between the substrate processing unit and the substrate unloading unit, and a control unit that controls each unit. According to this configuration, by including the light irradiation device or substrate processing device, a resist pattern with excellent heat resistance can be formed in a short time in the substrate processing system.

[0138] In addition, the components described above as embodiments or variations thereof may be combined as appropriate without departing from the spirit of the present invention, and some of the multiple combined components may not be used as appropriate. EXAMPLES

[0139] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0140] The resist composition (1) used in this example is shown below. Resist composition (1): 100 parts by mass of the alkali-soluble resin described below, 10 parts by mass of a sensitivity enhancer, and 23 parts by mass of a photosensitive component were uniformly dissolved in 429 parts by mass of an organic solvent, and then the solution was filtered using a membrane filter having a pore size of 0.2 μm to prepare a resist composition.

[0141] Alkali-soluble resin: A cresol novolak resin with a mass average molecular weight (Mw) of 4000 obtained by adding oxalic acid and formaldehyde to a mixture of 35 mol% m-cresol and 65 mol% p-cresol and undergoing a condensation reaction was used. The cresol novolak resin was then fractionated to obtain a cresol novolak resin with Mw=4500 and a dinuclear phenol content of approximately 6 mol%. Sensitivity enhancer: a phenol compound represented by the following chemical formula (V). Photosensitive component: an esterification product of 1 mole of a compound represented by the following chemical formula (VIII) and 2.34 moles of 1,2-naphthoquinone diazide-5-sulfonic acid chloride (hereinafter referred to as "5-NQD") (esterification rate: 59 mole %). Organic solvent: propylene glycol monomethyl ether acetate.

[0142] [ka]

[0143] <Evaluation> Using the above resist composition (1), a resist pattern was formed in the manner described below, and each evaluation was carried out.

[0144] [Formation of resist pattern] Example 1 Step (1): The resist composition (1) was applied to a 6-inch silicon wafer that had been treated with hexamethyldisilazane (HMDS) using a spinner, and the wafer was prebaked on a hot plate at 110° C. for 90 seconds and dried to form a resist film with a thickness of 2.5 μm. The wafer was then exposed to light through a predetermined mask pattern using an exposure device (product name G7E, manufactured by Nikon Corporation; NA 0.54). After that, alkaline development was performed for 65 seconds using a 2.38% by mass aqueous solution of tetramethylammonium hydroxide at a temperature of 23° C. As a result, a line and space prepattern was formed.

[0145] Step (2): Next, the prepattern was irradiated with light including both ultraviolet light and visible light to cure the prepattern. Step (2) was performed by a first irradiation step of irradiating the prepattern with ultraviolet light and visible light with attenuated wavelengths of less than 330 nm (including light with a wavelength of 350 nm to 450 nm based on a wavelength of 365 nm) and a second irradiation step of irradiating the prepattern with ultraviolet light and visible light with attenuated wavelengths of less than 230 nm (including light with a wavelength of 230 nm to 600 nm based on a wavelength of 254 nm). The conditions for curing by such light irradiation are shown below. Equipment: Ultraviolet irradiation equipment (manufactured by Tokyo Ohka Kogyo Co., Ltd.). Light source: 160W / cm high pressure mercury lamp Irradiation window: 25mm thick natural quartz window Irradiation time: 180 seconds Temperature when hardening the prepattern (temperature of the prepattern itself): 100°C. A thermocouple was placed on the substrate stage and measured while irradiating the cutting light. Heating temperature of substrate stage: Adjusted to 100℃. Atmosphere inside the equipment: N2 gas supplied, dew point -35°C (moisture concentration 600 ppm by mass), oxygen concentration 1000 ppm by mass. The temperature of the prepattern itself is determined by heating by the substrate stage (hot plate) and heating by radiation of light irradiation. Under such conditions of curing by light irradiation, the temperature of the prepattern itself becomes close to the heating temperature of the substrate stage due to the mutual influence of the temperature drop due to heat absorption by the substrate and the temperature rise due to radiation of light irradiation. In the first irradiation step, a bandpass filter that attenuates light in a wavelength range of less than 330 nm was provided for the light source. In the second irradiation step, the bandpass filter was removed from the light source. In Example 1, the irradiation time in the first irradiation step was 10 seconds, and the irradiation time in the second irradiation step was 170 seconds.

[0146] In Example 1, a line and space resist pattern with a line width of 1.5 μm and a pitch width of 3.0 μm was obtained by steps (1) and (2).

[0147] (Examples 2 to 4) Except for changing the irradiation time of the first irradiation step and the irradiation time of the second irradiation step, the same operation as in Example 1 (step (1) and step (2)) was performed to obtain a resist pattern. In Example 2, the irradiation time of the first irradiation step was 30 seconds, and the irradiation time of the second irradiation step was 150 seconds. In Example 3, the irradiation time of the first irradiation step was 60 seconds, and the irradiation time of the second irradiation step was 120 seconds. In Example 4, the irradiation time of the first irradiation step was 120 seconds, and the irradiation time of the second irradiation step was 60 seconds.

[0148] Comparative Example 1 Step (1): Using resist composition (1), a line and space prepattern was obtained in the same manner as in Example 1.

[0149] Step (2): Next, the obtained prepattern was irradiated with light including both ultraviolet light and visible light (with the bandpass filter removed from the light source) to cure the prepattern. The conditions for curing by light irradiation are as follows: Equipment: Ultraviolet irradiation equipment (manufactured by Tokyo Ohka Kogyo Co., Ltd.). Light source: 160W / cm high pressure mercury lamp Irradiation window: 25mm thick natural quartz window Irradiation time: 250 seconds Temperature when hardening the prepattern (temperature of the prepattern itself): 100°C. A thermocouple was placed on the substrate stage and measured while irradiating the cutting light. Heating temperature of substrate stage: Adjusted to 100℃. Atmosphere inside the equipment: N2 gas supplied, dew point -35°C (moisture concentration 600 ppm by mass), oxygen concentration 1000 ppm by mass. The temperature of the prepattern itself is determined by the heating caused by the substrate stage (hot plate) and the heating caused by the radiation of light irradiation. Under the conditions of curing by light irradiation, the temperature of the prepattern itself becomes close to the heating temperature of the substrate stage due to the mutual influence of the temperature drop caused by heat absorption by the substrate and the temperature rise caused by the radiation of light irradiation.

[0150] In Comparative Example 1, a line and space resist pattern with a line width of 1.5 μm and a pitch width of 3.0 μm was obtained by the above-mentioned operations.

[0151] [Heat resistance evaluation] The state (state after light irradiation) of the resist patterns obtained in Examples 1 to 4 and Comparative Example 1 was observed. The silicon wafers on which the resist patterns were formed were placed on a hot plate at temperatures of 150°C and 160°C, and heated for 5 minutes. The state of each resist pattern after heating was observed, and the heat resistance was evaluated. The results of the heat resistance evaluation are shown in Table 1. The evaluation was based on the following evaluation criteria. Evaluation criteria 5 points: The entire surface was a mirror surface, and no wrinkles or other imperfections were observed. 3 points: No wrinkles were observed, but slight lifting was observed in some areas. 2 points: Partial floating was observed. Score 1: Wrinkles were observed in some areas. Score 0: Wrinkles were observed all over the surface.

[0152] [Table 1]

[0153] As a result, in the state after heating of the resist patterns obtained in Examples 2 to 4, wrinkles were observed all over the surface and partial wrinkles were observed, which were not observed in the resist patterns obtained in Comparative Example 1 and Example 1. From this, it was confirmed that the resist pattern obtained in Example 1 has higher heat resistance than the resist patterns obtained in Examples 2 to 4. From this, it is considered that the resist pattern obtained in Example 1 is fully cured throughout its entirety, even to its inside, and it can be said that it also has high dry etching resistance. Furthermore, it was confirmed that the heat resistance of the resist pattern obtained in Example 1 is comparable to that of the resist pattern obtained in Comparative Example 1. From the above, it was found that the conditions of the first irradiation step and the second irradiation step in Example 1 are conditions that allow a resist pattern with excellent heat resistance to be formed in a short time. [Explanation of symbols]

[0154] 1,201,301,401…Light irradiation device 2...Substrate 3,203,403…Light irradiation unit 4. Control section 10…Light source 11...Optical filter 12...Detachable mechanism 210A,410A…First light source 210B,410B…Second light source 212…exchange mechanism 300...Substrate processing apparatus 360... Coating device 361...Exposure equipment 362...Developing device

Claims

1. A method for forming a resist pattern, comprising exposing a resist film formed on a substrate using a positive resist composition containing a phenol resin and a quinone diazide compound, and then developing the resist film to form a prepattern that is hardened, a first step of irradiating the prepattern with ultraviolet and visible light having wavelengths of less than 330 nm attenuated by disposing an optical filter that attenuates light having wavelengths of less than 330 nm relative to a light source; a second step of removing the optical filter from the light source after the first step and irradiating the prepattern with light including both ultraviolet light and visible light.

2. A method for forming a resist pattern, comprising exposing a resist film formed on a substrate using a positive resist composition containing a phenol resin and a quinone diazide compound, and then developing the resist film to form a prepattern that is hardened, A first step of irradiating the prepattern with light in which the wavelength range of ultraviolet light and visible light less than 330 nm is attenuated by a first light source that emits light in which the wavelength range of ultraviolet light and visible light less than 330 nm is attenuated; a second step of irradiating the prepattern with light including both ultraviolet light and visible light by a second light source different from the first light source after the first step.

3. 3. The method for forming a resist pattern according to claim 1, wherein in the second step, the prepattern is irradiated with ultraviolet light and visible light having a wavelength of less than 230 nm that is attenuated.

Images