Method for forming resist pattern, method for producing semiconductor device, substrate treatment apparatus, and memory medium

Abstract

To form a resist pattern with high contrast when forming a fine resist pattern by EUV lithography.SOLUTION: A method for forming a resist pattern is disclosed, which includes: irradiating part of a resist film containing metal oxide resist materials with extreme ultraviolet light; irradiating the entire area of the resist film, which includes the portion irradiated with extreme ultraviolet light and the other parts, with ultraviolet light having a wavelength of 100 nm or more; and forming a resist pattern by developing to remove part of the resist film, in this order.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a method for forming a resist pattern, a method for manufacturing a semiconductor device, a substrate processing apparatus, and a storage medium. [Background technology]

[0002] Conventionally, extreme ultraviolet (EUV) lithography technology using a chemically amplified resist material has been applied to form a fine resist pattern having a size of 20 nm (Patent Document 1). In order to form a fine resist pattern by EUV lithography, it has been proposed to apply a non-chemically amplified resist material (Patent Document 1 and Non-Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2020 / 0064733 [Non-patent literature]

[0004] [Non-Patent Document 1] J. Micro / Nanolith. MEMS MOEMS 16(2), 023510 (Apr-Jun 2017) Summary of the Invention [Problem to be solved by the invention]

[0005] When forming a fine resist pattern by EUV lithography, it is desirable to be able to form the resist pattern with high contrast. [Means for solving the problem]

[0006] One aspect of the present disclosure relates to a method for forming a resist pattern, the method including, in this order, irradiating with extreme ultraviolet light a portion of a resist film containing a resist material including a metal oxide resist material, irradiating with ultraviolet light having a wavelength of 100 nm or more an entire region of the resist film, including the portion irradiated with the extreme ultraviolet light and other portions, and forming a resist pattern by development that removes a portion of the resist film. Effect of the Invention

[0007] According to the method of the present disclosure, a fine resist pattern formed by extreme ultraviolet (EUV) lithography can be formed with high contrast. [Brief description of the drawings]

[0008] [Figure 1] 1 is a flowchart showing an example of a method for forming a resist pattern. [Diagram 2] 1A to 1C are process diagrams illustrating an example of a method for manufacturing a semiconductor device by a method including forming a resist pattern. [Diagram 3] 1A to 1C are process diagrams illustrating an example of a method for manufacturing a semiconductor device by a method including forming a resist pattern. [Figure 4] 1A to 1C are process diagrams illustrating an example of a method for manufacturing a semiconductor device by a method including forming a resist pattern. [Diagram 5] 1 is a flowchart showing an example of a method for forming a resist pattern. [Figure 6] 1 is a flowchart showing an example of a method for forming a resist pattern. [Figure 7] FIG. 1 is a schematic diagram illustrating an example of a substrate processing apparatus. [Figure 8] FIG. 1 is a schematic diagram illustrating an example of a substrate processing apparatus. [Figure 9] FIG. 2 is a schematic diagram showing an example of an exposure unit. [Figure 10]1 is a graph showing the relationship between the thickness of a resist film remaining after development processing and the EUV dose. [Figure 11] 1 is a graph showing the relationship between the thickness of a resist film remaining after development processing and the EUV dose. [Figure 12] 1 is a graph showing the relationship between the thickness of a resist film remaining after development processing and the EUV dose. [Figure 13] 1 is a graph showing the relationship between line width (CD) of a resist pattern and EUV dose. [Figure 14] 1 is a graph showing the relationship between line width roughness (LWR) and line width (CD) of a resist pattern. [Figure 15] 1 is a graph showing the relationship between the number of defects and the line width (CD) of a resist pattern. [Figure 16] 1 is a graph showing the relationship between line width (CD) of a resist pattern and EUV dose. [Figure 17] 1 is a graph showing the relationship between the thickness of a resist film remaining after development processing and the dose of a KrF excimer laser. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present disclosure will be described in order to explain the present invention. However, the present invention should not be limited to the following contents. In the following description, the same elements or elements having the same functions are designated by the same reference numerals, and duplicated descriptions may be omitted.

[0010] FIG. 1 is a flow chart showing an example of a method for forming a resist pattern, and FIGS. 2, 3 and 4 are process diagrams showing an example of the method for forming a resist pattern and a method for manufacturing a semiconductor device that includes forming a resist pattern by that method.

[0011] The method for forming the resist pattern shown in FIGS. 1 to 4 includes, in this order, a step S10 of applying a photoresist composition onto an underlayer film 3 (film to be etched) provided on a semiconductor wafer 1, a step S11 of baking the applied photoresist composition to form a resist film 5, a step S20 of pattern exposure in which a part (5E) of the resist film 5 is irradiated with extreme ultraviolet rays R1, a step S30 of post-exposure baking in which the resist film 5 after the pattern exposure is baked, a step S40 of flood exposure in which the whole region of the resist film 5 including the part 5E irradiated with extreme ultraviolet rays R1 and the other parts is irradiated with ultraviolet rays R2, and a step S50 of development in which a part of the resist film 5 is removed by development to form a resist pattern 5A having a trench 5a in which the underlayer film 3 is exposed. Extreme ultraviolet rays R1 are radiation having a wavelength of less than 100 nm, and are abbreviated as EUV. The wavelength of EUV may be, for example, 13.5 nm. Ultraviolet rays R2 are radiation having a wavelength of 100 nm or more. The post-exposure bake step S30 may be omitted.

[0012] The resist film 5 includes a resist material. The photoresist composition used to form the resist film 5 includes a resist material and a solvent. The resist material can be a metal oxide photoresist material.

[0013] The metal oxide photoresist material may include, for example, an organometallic compound including a metal oxide containing a metal atom and an organic ligand bonded to the metal atom. The metal oxide photoresist material may not include an acid generator. The metal oxide photoresist material may be nanoparticles (particles having a maximum width of less than 1 μm). The metal oxide may be a cage compound. It is considered that the metal oxide photoresist material containing an organometallic compound forms a crosslinked structure through a reaction including the detachment of an organic ligand from a metal atom by irradiation with extreme ultraviolet light R1, and the bonding of the metal atoms from which the organic ligand has been detached via an oxygen atom or the like through a condensation reaction. Since the formed crosslinked structure is substantially insoluble in the developing material, the metal oxide photoresist material can function as a negative resist material. When the metal oxide photoresist material is nanoparticles, a plurality of nanoparticles may be linked to form an aggregate (crosslinked structure) that is substantially insoluble in the developing material. The formation of the aggregate may be promoted by post-exposure baking (step S30). After the aggregates are formed, the solubility of the resist film 45 in the developing material of the portion (unexposed portion) other than the portion 5E irradiated with the extreme ultraviolet ray R1 is changed by the flood exposure with ultraviolet ray R2 (step S40). This is believed to be because the ultraviolet ray R2 forms a metal hydroxide from the metal oxide, thereby increasing the hydrophilicity (polarity) of the resist film. Based on the change in the solubility of the resist film by the ultraviolet ray R2, the dissolution contrast during development of the resist film increases. It is believed that the increase in contrast contributes to reducing the roughness of the resist pattern to be formed.

[0014] By performing the pattern exposure with extreme ultraviolet ray R1 (step S20) and, optionally, the post-exposure bake (step S30) after the aggregates of the metal oxide photoresist material are sufficiently formed, the block exposure (step S40) can promote the detachment of organic ligands and the formation of metal hydroxides while suppressing the formation of aggregates (crosslinked structures) in the portions other than the portion 5E irradiated with extreme ultraviolet ray R1. This can contribute to improving the contrast of development. If ultraviolet light is irradiated before the pattern exposure with extreme ultraviolet ray R1 (step S20), the formation of aggregates progresses in the portions other than the portion 5E irradiated with extreme ultraviolet ray R1, so that the contrast may decrease. By performing the block exposure with ultraviolet ray (step S40), the detachment of organic ligands remaining in the aggregates may progress in the portion 5E irradiated with extreme ultraviolet ray R1. When the organic ligands are detached, the resist film becomes hydrophilic, and the solubility in organic solvents decreases. As a result, the sensitivity can be further improved.

[0015] The metal oxide of the metal oxide photoresist material may contain at least one metal atom selected from the group consisting of Sn, Sb, In, Ti, Zr, Hf, V, Co, Mo, W, Al, Ga, Si, Ge, P, As, Y, La, Ce, and Lu. The organic ligand bonded to the metal atom of the metal oxide may be, for example, a branched or unbranched alkyl group which may have a substituent, or a cycloalkyl group which may have a substituent. The alkyl group and the cycloalkyl group may be bonded to the metal atom at a primary, secondary, or tertiary carbon atom. The number of carbon atoms of the alkyl group and the cycloalkyl group may be 1 to 30. Examples of the alkyl group as the organic ligand include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, and an n-octyl group. Examples of the cycloalkyl group as the organic ligand include a cyclobutyl group, a cyclopropyl group, a cyclohexyl group, a 1-adamantyl group, and a 2-adamantyl group. Examples of the substituents that the alkyl and cycloalkyl groups may have include cyano, alkylthio, silyl, alkyloxy, alkylcarbonyl, alkylcarbonylyl, and halogeno groups. Nanoparticles containing caged tin oxide and organic ligands can be, for example, represented by the formula: [(SnR) 12 O 14 (OH)6](OH)2 (R represents an organic ligand).

[0016] The solvent constituting the photoresist composition used to form the resist film 5 is selected from those capable of dispersing or dissolving the resist material. Examples of the solvent include ketones such as cyclohexanone and methyl-2-amyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; and esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol monomethyl ether acetate, and propylene glycol monotert-butyl ether acetate.

[0017] The amount of solvent in the photoresist composition is adjusted within a range in which resist film 5 can be appropriately formed by a method such as spin coating. For example, the amount of solvent may be 500 to 100,000 parts by mass per 100 parts by mass of the metal oxide photoresist material.

[0018] The photoresist composition is applied onto the underlayer film 3 by, for example, spin coating (step S10). The applied photoresist composition is baked to remove the solvent in the photoresist composition (step S11). A pre-formed resist film 5 may be laminated on the underlayer film 3. The thickness of the resist film 5 may be, for example, 1 to 5000 nm, 10 to 1000 nm, or 30 to 200 nm.

[0019] The resist film 5 may be formed by a gas phase deposition method instead of a method of applying and baking a photoresist composition. Examples of applicable gas phase deposition methods include physical vapor deposition (PVD), chemical vapor deposition (CVD), and atomic layer deposition (ALD). The resist film 5 may be formed by a gas phase deposition method including supplying a reaction gas containing a precursor of an organometallic compound constituting a metal oxide photoresist material and a co-precursor (e.g., water) that reacts with the precursor to generate an organometallic compound to a gas phase to which the underlayer film 3 is exposed. The organometallic compound generated by the reaction of the precursor with the co-precursor in the gas phase may be deposited on the underlayer film 3, or the organometallic compound may be generated by the reaction of the precursor deposited on the underlayer film 3 with the co-precursor.

[0020] The underlayer film 3 may be a film containing a silicon-containing material containing a silicon atom and a carbon atom bonded to the silicon atom. The underlayer film 3 containing a silicon-containing material may be, for example, a film formed by heating a film of a composition containing polycarbosilane having an organic group bonded to a silicon atom, or polysiloxane having an organic group bonded to a silicon atom. The underlayer film 3 containing a silicon-containing material is easy to absorb ultraviolet light R2. Therefore, irradiation with ultraviolet light R2 particularly promotes the detachment of organic ligands in the region (lower region) of the resist film 5 near the underlayer film 3, and the region may become hydrophilic. When the region of the resist film 5 near the underlayer film 3 becomes hydrophilic, the solubility of the part 5E irradiated with extreme ultraviolet light R1 in the developing material decreases, particularly when the developing material is an organic material, so that the wall surface of the resist pattern is not greatly inclined with respect to the underlayer film 3, and a resist pattern having a wall surface perpendicular to or along a direction close to the thickness direction of the underlayer film 3 is easily formed. It is considered that irradiating the resist film 5 with ultraviolet light R2 after it is formed facilitates the detachment of organic ligands from the lower region of the resist film 5, i.e., facilitates hydrophilization, rather than irradiating the resist film 5 with ultraviolet light R2 before it is formed. The reason for this is that when irradiating the resist film 5 with ultraviolet light R2 before it is formed, the effect of the underlayer film in promoting the detachment of organic ligands from the lower region of the resist film 5 becomes relatively weaker due to the passage of time until the resist film 5 is formed. Even when irradiating the resist film 5 with ultraviolet light R2 after it is formed, the wavelength of the ultraviolet light R2 is sufficiently longer than the wavelength of EUV, so the ultraviolet light R2 reaches the underlayer film 3.

[0021] The formed resist film 5 is irradiated with extreme ultraviolet rays R1 through a mask 7 having openings arranged on the resist film 5 (step S20). As a result, the portions (5E) of the resist film 5 exposed in the openings of the mask 7 are irradiated with extreme ultraviolet rays R1 having a pattern corresponding to the openings. Instead of using a mask, the extreme ultraviolet rays R1 may be irradiated along a predetermined pattern.

[0022] After irradiation with extreme ultraviolet rays R1, the mask 7 is removed, and the resist film 5 is baked (step S30). Heating for baking after pattern exposure with extreme ultraviolet rays R1 can be performed in the air, in an inert gas atmosphere such as nitrogen and argon, or in a humidified environment. The pressure of the atmosphere for the post-exposure bake may be atmospheric pressure or a pressure lower than atmospheric pressure. The heating temperature may be 50 to 250°C, or 170 to 250°C, and the heating time may be 10 to 300 seconds, or 50 to 300 seconds. If the heating temperature for the post-exposure bake is high, the contrast of development can be further improved when the developing material is an alkaline aqueous solution or water. The post-exposure bake may be a one-step heating at a constant temperature, or may include two or more steps of heating at different temperatures. For example, the post-exposure bake may include a first step of heating at a temperature of 80 to 170°C and a second step of heating at a temperature of 180 to 250°C. The first step may be carried out in air or in a humidified environment to promote the formation of metal hydroxides by hydrolysis, and the second step may be carried out at atmospheric pressure, under reduced pressure, or in an inert gas environment.

[0023] Next, ultraviolet rays R2 are irradiated onto the entire region of the resist film 5, including the portion 5E irradiated with extreme ultraviolet rays R1 and the other portions (step S40, flood exposure). When ultraviolet rays R2 are irradiated, the solubility of the portion 5E irradiated with extreme ultraviolet rays R1 in the developing material is selectively changed. In this specification, flood exposure includes not only the case where the entire region of the resist film 5, including the portion 5E irradiated with extreme ultraviolet rays R1 and the other portions, is simultaneously exposed to ultraviolet rays, but also the case where the exposed region is moved so that the entire region is exposed while a part of the region is exposed.

[0024] The ultraviolet ray R2 may be ultraviolet ray having a wavelength of 100 nm or more and 450 nm or less, or 100 nm or more and 300 nm or less. The wavelength of the ultraviolet ray R2 may be 170 nm or more, 200 nm or more, or 250 nm or more. The ultraviolet ray having a wavelength of 170 nm or more is suitable for collective exposure in the atmosphere, for example. The ultraviolet ray having a wavelength of 200 nm or more can suppress secondary reactions such as oxidation reactions. The ultraviolet ray R2 may be ultraviolet ray having a wavelength of 254 nm, 270 nm, 280 nm, 365 nm, 385 nm, or 395 nm, or may be ultraviolet ray having a wavelength of 254 nm, 270 nm, or 280 nm. The light source of the ultraviolet ray R2 may be, for example, a mercury lamp, a xenon lamp, an LED, or a laser light source. These can be easily mounted in the exposure unit described later. The LED is particularly excellent in terms of high-precision control of the exposure amount and long-term exposure amount stability, and can be applied to control the size of the resist pattern with high precision. The dose of UV R2 (e.g. UV from LED) is, for example, 0.005 to 100 J / cm 2 , 0.005~90J / cm 2 , 0.005~80J / cm 2 , 0.005~70J / cm 2 , 0.005~60J / cm 2 , 0.005~50J / cm 2 , 0.005~40J / cm 2 , 0.005~30J / cm 2 , or 0.005 to 20 J / cm 2 The dose of ultraviolet light R2 may be 1 J / cm 2 More than 2J / cm 2 More than 3J / cm 2 More than 4J / cm 2 or more than 5J / cm 2 The exposure to ultraviolet light R2 can be performed by immersion lithography or dry lithography.

[0025] Subsequently, a part of the resist film 5 is removed by development, thereby forming a resist pattern 5A having a trench 5a exposing the underlayer film 3 (step S50, FIG. 4(f)). The part 5E irradiated with the extreme ultraviolet ray R1 is not substantially dissolved in the developing material and remains as the resist pattern 5A.

[0026] The development can be wet development, which involves contacting the resist film 5 with a developer, or dry development, which involves exposing the resist film 5 to a developing gas.

[0027] The developer for the wet development is selected from those that efficiently dissolve the portions other than the portion 5E irradiated with the extreme ultraviolet ray R1. The developing material can be, for example, an organic developer, an alkaline aqueous solution, or water.

[0028] Examples of organic developers are methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxyacetate, ethyl ethoxyacetate, 2-heptanone, propylene glycol monomethyl ether acetate, isopropyl alcohol, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ... monoethyl ether acetate, propylene glycol monopropyl ether acetate, 2-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, 4-methyl-4-methoxypentyl acetate, propylene glycol diacetate, methyl formate ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate,and propyl-3-methoxypropionate. The organic developer may be a mixture of these with an organic acid (acetic acid, citric acid, etc.). The organic developer may be butyl acetate, 2-heptanone, propylene glycol monomethyl ether acetate, or a mixture of these with an organic acid (acetic acid, citric acid, etc.). After development with the organic developer, the hydrophilized portion of the unexposed area may be removed by rinsing with an alkaline aqueous solution (e.g., an aqueous tetramethylammonium hydroxide solution) or water.

[0029] The alkaline aqueous solution used as the developer may contain, for example, inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, primary amines such as ethylamine and n-propylamine, secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and choline, and cyclic amines such as pyrrole and piperidine. The alkaline aqueous solution may contain alcohols such as isopropyl alcohol, and surfactants such as nonionic surfactants. The developer may be an alkaline aqueous solution containing a quaternary ammonium salt, or tetramethylammonium hydroxide or tetrabutylammonium hydroxide. Rinsing after development with the alkaline aqueous solution may be performed using water or an organic solvent.

[0030] The developing gas for dry development may be an acidic gas. The acidic gas may be, for example, a gas containing one or more acid components selected from HBr, acetic acid, and BCl3. The developing gas may contain a gas formed by vaporizing the above-mentioned developer. Dry development may be performed under atmospheric pressure or under an atmosphere with a pressure lower than atmospheric pressure.

[0031] After the development process, the end faces and the back face of the semiconductor wafer 1 may be washed with a cleaning liquid. The cleaning liquid may be water, an alkaline aqueous solution, or an organic solvent. The organic solvent may contain an acid component or an alkaline component.

[0032] FIG. 5 is a flow chart showing another example of a method for forming a resist pattern. The method shown in FIG. 5 includes a pre-developing step (step S35) for preliminarily developing the resist film after post-exposure baking (step S30) and before flood-exposure with ultraviolet light (step S40). The pre-developing can be wet development by contact with a developer, or dry development. The pre-developing can further improve the sensitivity. The pre-developing can be particularly effective, for example, when the resist material is a metal oxide photoresist material. The pre-developing can be wet development by a developer, and the development after the flood-exposure can be wet development by a developer or dry development. The line width (CD) of the resist pattern after the pre-developing can be measured, and the dose of the flood-exposure can be adjusted based on the measured line width.

[0033] FIG. 6 is a flow chart showing yet another example of a method for forming a resist pattern. The method shown in FIG. 6 differs from the method shown in FIG. 1 in that it includes a post-development bake step S60 in which the formed resist pattern is baked after the development step S50. The temperature for this post-development bake may be higher than the temperature of the post-exposure bake step S30, and may be, for example, 230 to 300° C. The heating time for the post-exposure bake may be 30 to 300 seconds. The post-development bake can efficiently remove residues in regions other than the portion 5E irradiated with the extreme ultraviolet ray R1. In the region (unexposed portion) other than the portion 5E irradiated with the extreme ultraviolet ray R1, the resist material is depolymerized by the detachment of organic ligands due to the irradiation of the ultraviolet ray R2, and is in a state in which it is easily vaporized by heat. Therefore, the combination of the irradiation of the ultraviolet ray R2 and the post-exposure bake can efficiently remove the residues of the resist material. It is considered that if the temperature of the post-development bake is higher than the temperature of the post-exposure bake, the residues are easily decomposed and the removal efficiency is further improved.

[0034] The conditions of the development step S50 may be conditions under which the resist film is preliminarily developed, and the development may be completed by the post-development bake step S60. In this case, since the resist pattern is not completely resolved in the development step S50, distortion and collapse of the pattern are particularly unlikely to occur. Furthermore, since no liquid is used in the post-development bake step S60, it is possible to adjust the pattern shape while avoiding distortion and collapse of the pattern caused by the surface tension of the liquid. An example of the adjustment of the pattern shape includes forming a resist pattern having a size larger than the target size and / or a surface rougher than the target roughness in the development step S50, and reducing the size of the resist pattern and / or the surface roughness of the resist pattern in the post-development bake step S60 to form a resist pattern having a size and roughness closer to the target size and roughness.

[0035] The method for forming a resist pattern may further include exposing the resist pattern formed by development to ultraviolet light. The ultraviolet light source for exposure after development may be an LED or UV lamp that emits light having a peak between 160 nm and 420 nm.

[0036] The method for manufacturing a semiconductor device further includes a step of etching the underlayer film 3 exposed in the trenches 5a of the resist pattern 5A, thereby forming a patterned underlayer film 3A so as to form trenches 3a, as shown in (g) and (h) of Figure 4. The method for etching the underlayer film 3 can be selected in consideration of the type of material constituting the underlayer film 3, and may be, for example, dry etching or wet etching. After etching, the resist pattern 5A may be removed. By the method illustrated in Figure 4, a semiconductor wafer 1 and a processed substrate 10 having a patterned underlayer film 3A are obtained.

[0037] The patterned lower layer film 3A may be, for example, an active layer, a lower layer insulating film, a gate electrode film, or an upper layer insulating film. Wiring may be embedded in the trench 3a of the lower layer film 3A. By using the method according to the present disclosure, for example, a semiconductor device including an integrated circuit including a semiconductor substrate and a patterned lower layer film formed on the semiconductor substrate can be manufactured.

[0038] A lithography mask or a nanoimprint template can also be manufactured by etching using the resist pattern formed by the method according to the present disclosure as a mask. The lithography mask may be a transmission mask or a reflection mask.

[0039] For the above-exemplified method, for example, a substrate processing apparatus can be used that is mainly composed of a heat treatment unit that bakes a resist film formed on a workpiece having an underlayer film, an exposure unit that irradiates ultraviolet rays onto the resist film having a portion that has been irradiated with extreme ultraviolet rays, a development unit that removes a portion of the resist film by development, thereby forming a resist pattern, and a control unit that controls the exposure unit so that the ultraviolet rays are irradiated all at once onto the entire area of ​​the resist film, including the portion that has been irradiated with extreme ultraviolet rays and the other portions.

[0040] Figures 7 and 8 are schematic diagrams showing an example of a substrate processing apparatus. Figure 7 also shows an example of an exposure apparatus used in combination with the substrate processing apparatus. Figure 8 shows an example of the internal configuration of the substrate processing apparatus 20 shown in Figure 7. The substrate processing apparatus 20 shown in Figures 7 and 8 includes a carrier block 24, a processing block 25, and an interface block 26. The substrate processing apparatus 20 processes the workpiece W by the above-mentioned method.

[0041] The carrier block 24 is a block configured to introduce the workpiece W into the substrate processing apparatus 20 and to remove the workpiece W from the substrate processing apparatus 20 to the outside. The carrier block 24 has a transport device A1 including a delivery arm. The transport device A1 takes out the workpiece W accommodated in the carrier C and delivers it to the processing block 25, and receives the workpiece W from the processing block 25 and returns it to the carrier C.

[0042] The processing block 25 has processing modules 11, 12, 13, and 14, which are stacked in this order. Each of the processing modules 11, 12, 13, and 14 incorporates a plurality of processing units U1, U2, and a transport device A3 that transports the workpieces W to these processing units.

[0043] The processing module 11 may be configured to form an underlayer film (film to be etched) on a surface of a substrate (e.g., a semiconductor wafer) serving as the workpiece W. In the processing module 11, for example, the processing unit U1 may be a liquid processing unit that applies a coating liquid for forming the underlayer film to the workpiece W, and the processing unit U2 may be a heat processing unit that heat-treats the applied coating liquid to form the underlayer film.

[0044] The processing module 12 may be configured to form a resist film on an underlying film (film to be etched) of the workpiece W. In the processing module 12, for example, the processing unit U1 may be a coating unit that applies a photoresist composition to the workpiece W, and the processing unit U2 may be a heat treatment unit that bakes the applied photoresist composition to form a resist film. The workpiece W having the resist film may be transported to the exposure device 30 via the interface block 26, where extreme ultraviolet light may be irradiated onto a part of the resist film.

[0045] The processing module 13 may be configured to bake the resist film having a portion irradiated with extreme ultraviolet light in the exposure apparatus 30, and then irradiate the entire resist film with ultraviolet light. In the processing module 13, for example, the processing unit U1 may be a heat treatment unit for baking the resist film before it is irradiated with ultraviolet light, and the processing unit U2 may be an exposure unit having a light source of ultraviolet light.

[0046] The exposure unit for irradiating the resist film with ultraviolet light may have an ultraviolet light source module fixed inside the exposure unit. In this case, the workpiece W may be irradiated with ultraviolet light by passing through an exposure area where the workpiece W is exposed to ultraviolet light from the light source module. The exposure unit may have a mechanism for rotating the workpiece W while the workpiece W passes through the exposure area. By irradiating the workpiece W with ultraviolet light while rotating the workpiece W, variation in the irradiated dose can be suppressed.

[0047] FIG. 9 is a schematic diagram showing an example of an exposure unit. The exposure unit 40 shown in FIG. 9 has a rectangular housing 41, a moving mechanism 50, a support 51, and a light source module 60 provided inside the housing 41. A transfer port 42, which is an opening for inserting and removing the workpiece W, is provided on the side wall of the housing 41. The moving mechanism 50 is provided on the bottom surface inside the housing 41, and the support 51 is attached to the moving mechanism 50. The support 51 has a support base 52 fixed to the moving mechanism 50, a rotating unit 53 extending vertically upward from the support base 52, and a disk-shaped mounting base 54 attached to the upper end of the rotating unit 53. The workpiece W introduced from the transport port 42 is placed on the mounting base 54. The mounting base 54 adsorbs and holds the workpiece W. The housing 41 is usually placed so that the bottom surface on which the moving mechanism unit 50 is provided is horizontal, and the workpiece W is held on the mounting table 54 so that its main surface is horizontal.

[0048] The light source module 60 is provided inside the housing 41 above the movement mechanism 50 and the support 51. The light source module 60 has a housing 61 and a light source 62 provided inside the housing 61. The housing 61 has an opening 61a formed directly below the light source 62, and is also provided with a shutter 63 for opening and closing the opening 61a. The shutter 63 moves between a closed position where the opening 61a is blocked and an open position where the opening 61a is opened, by a shutter movement mechanism 64 provided inside the housing 61.

[0049] With the light source 62 turned on and the shutter 63 moved to the open position to open the opening 61a, the support part 51 is moved horizontally inside the housing 41 by the movement mechanism part 50, whereby the entire resist film of the workpiece W is irradiated with ultraviolet light. During this time, the rotating part 53 rotates, causing the workpiece W to rotate about its central axis.

[0050] The processing module 14 may be configured to function as a developing unit that removes a part of the resist film irradiated with ultraviolet light by contacting it with a developing material, thereby forming a resist pattern. In the processing module 14, for example, the processing unit U1 may be a liquid processing unit that supplies a developing material and, if necessary, a rinsing liquid to the resist film, and the processing unit U2 may be a heat processing unit for heat-treating the resist film before development. The batch exposure of the resist film to ultraviolet light by the exposure unit is performed continuously in-line with the baking by the heat processing unit and the development by the liquid processing unit, which is advantageous in terms of shortening the processing time and suppressing the influence of size fluctuations of the resist film during the process.

[0051] The processing block 25 further has a shelf unit U10 provided on the carrier block 24 side. The shelf unit U10 is divided into multiple cells lined up in the vertical direction. A transport device A7 including a lifting arm is provided near the shelf unit U10. The transport device A7 raises and lowers the workpiece W between the cells of the shelf unit U10. The processing block 25 has a shelf unit U11 provided on the interface block 26 side. The shelf unit U11 is divided into multiple cells lined up in the vertical direction.

[0052] The interface block 26 is configured to transfer the workpiece W between the processing block 25 and the exposure device 30. The interface block 26 has a built-in transport device A8 (transport unit) including a transfer arm. The transport device A8 transfers the workpiece W placed on the shelf unit U11 to the exposure device 30. The transport device A8 receives the workpiece W from the exposure device 30 and returns it to the shelf unit U11.

[0053] The control device 100 (control unit) controls the units constituting each block so that a desired resist pattern is formed on the workpiece W. For example, the control device 100 controls an exposure unit (e.g., a processing unit U1 in a processing module) so that ultraviolet rays are irradiated collectively onto the entire area of ​​the resist film, including the portion irradiated with extreme ultraviolet rays and the other portion. The control device 100 can also control a transport unit (transport device A8) of the interface block 26 so that a workpiece having a resist film irradiated with extreme ultraviolet rays in the exposure device 30 is transported to the exposure unit.

[0054] The control device 100 may have a storage that stores a program for causing the units constituting each block to execute the above-mentioned method. The storage includes, for example, a computer-readable storage medium that stores the program, and a device that reads data from the storage medium. The storage medium is a non-transitory medium, and examples of the storage medium include a hard disk and a read only memory (ROM).

[0055] The specific configuration of the substrate processing apparatus is not limited to the above-described configuration of the substrate processing apparatus 20. For example, an exposure unit that irradiates ultraviolet rays onto the resist film having a portion irradiated with extreme ultraviolet rays may be provided between the processing block and the interface block. EXAMPLES

[0056] The present invention is not limited to the following verification examples. 1. Photoresist composition As a resist material, nanoparticles having cage-shaped tin oxide compounds and organic ligands ([(SnR) 12 O 14 ((OH)6](OH)2, where R is an alkyl group, hereinafter sometimes referred to as "MOR") was prepared. A 0.01M MOR solution was prepared as a photoresist composition.

[0057] 2. Resist underlayer film An underlayer film containing a silicon-containing material that contains silicon atoms and carbon atoms was formed by applying a coating liquid for forming an underlayer film, which contains polycarbosilane that contains a structural unit having a silicon atom and a hydrocarbon group bonded to the silicon atom, to the entire surface of a silicon wafer and heating the coating film.

[0058] 3. Verification Test Test 1 The photoresist composition was applied onto an underlayer film formed on a silicon wafer using a spin coater. The coating film was heated at 100°C for 60 seconds to remove the solvent, forming a resist film with a thickness of about 15 nm. The resist film was exposed to extreme ultraviolet (EUV) rays having a wavelength of 13.5 nm. The exposure dose was 0 mJ / cm. 2 (without exposure) to 46 mJ / cm 2 By exposing multiple regions while sequentially changing the exposure dose from 0 to 100 mJ / cm, multiple resist films including regions with different doses of EUV were prepared. The exposed resist film was baked by heating at 180°C for 60 seconds. The entire surface of the baked resist film was exposed in one go to a KrF excimer laser (wavelength: 248 nm). The dose was 0 mJ / cm. 2 (without exposure), 10mJ / m 2 , 20mJ / m 2 , or 30 mJ / m 2Each of the resist films was exposed to a KrF excimer laser so that the resist film was developed using a developer (PGMEA / AA) containing propylene glycol monomethyl ether acetate and acetic acid. The thickness of the resist film remaining after the development process was measured.

[0059] Figure 10 is a graph showing the relationship between the thickness of the resist film remaining after development processing and the EUV dose. It was found that the thickness of the remaining resist film tends to change with higher contrast with the EUV dose due to ultraviolet light exposure after EUV exposure.

[0060] Test 2 The photoresist composition was applied onto an underlayer film formed on a silicon wafer using a spin coater. The coating was heated at 100°C for 60 seconds to remove the solvent, forming a resist film with a thickness of about 15 nm. The resist film was exposed to a KrF excimer laser at a dose of 0 J / cm. 2 (without exposure) to 46 J / cm 2 By exposing multiple regions while sequentially changing the exposure dose from 0 to 100 mJ / cm, multiple resist films including regions with different doses of EUV were prepared. The exposed resist film was baked by heating at 180°C for 60 seconds. The entire surface of the baked resist film was exposed in one go to a KrF excimer laser (wavelength: 248 nm). The dose was 0 mJ / cm. 2 (no exposure), or 10 mJ / cm 2 Each of the resist films was exposed to a KrF excimer laser in a single step so that the resist film was developed using an aqueous solution of tetramethylammonium hydroxide (TMAH). The thickness of the resist film remaining after the development process was measured.

[0061] Figure 11 is a graph showing the relationship between the thickness of the resist film remaining after development processing and the dose of the first KrF excimer laser. It was confirmed that the thickness of the resist film changes with high contrast against the dose by the batch exposure to UV light after the exposure to the KrF excimer laser. It was also confirmed that the amount of residue in areas with low doses of the KrF excimer laser tends to be further reduced compared to when PGEMA / AA was used as the developer. It is believed that the contrast against the dose also tends to improve in the case of pattern exposure with EUV.

[0062] Test 3 The photoresist composition was applied onto an underlayer film formed on a silicon wafer using a spin coater. The coating film was heated at 100°C for 60 seconds to remove the solvent, forming a resist film with a thickness of about 15 nm. The resist film was exposed to EUV at a dose of 0 J / cm. 2 (without exposure) to 46 J / cm 2 By exposing multiple areas while sequentially changing the exposure temperature from 100 to 200°C, multiple resist films including areas with different doses of EUV were prepared. The exposed resist film was baked by heating at 200°C for 60 seconds. The entire surface of the baked resist film was exposed to a KrF excimer laser (wavelength: 248 nm) or Xe excimer laser (wavelength: 172 nm) in one go. The resist film after the one-time exposure to the KrF excimer laser or Xe excimer laser was developed with an aqueous tetramethylammonium hydroxide solution (TMAH). The thickness of the resist film remaining after the development process was measured with a thickness measurement system (KLA Tencor Aleris).

[0063] Figure 12 is a graph showing the relationship between the thickness of the resist film remaining after development processing and the EUV dose. For comparison, the results of Test 1 without flood exposure with KrF excimer laser are also shown in Figure 12. It was found that flood exposure with ultraviolet light after EUV exposure showed a tendency for the thickness of the remaining resist film to change with high contrast against the EUV dose, even when the ultraviolet light had a wavelength of 172 nm.

[0064] Test 4 The photoresist composition was applied onto an underlayer film formed on a silicon wafer using a spin coater. The coating was heated at 160°C for 60 seconds to remove the solvent, forming a resist film with a thickness of 22 nm. The resist film was exposed to EUV through a mask having a pattern corresponding to a line / space with a half pitch of 16 nm. A plurality of resist films irradiated with different doses of EUV were prepared. After exposure, the resist film was baked by heating at 200°C for 60 seconds. The entire surface of the baked resist film was exposed in one go to a KrF excimer laser. The dose of the KrF excimer laser was 70 mJ / cm. 2 The resist film after the floodwise exposure with the KrF excimer laser was developed with TMAH. The resist film after EUV exposure similar to that described above was baked by heating at 180° C. for 60 seconds without being subjected to full-scale exposure with a KrF excimer laser. The baked resist film was developed with TMAH. After the development process, the formed linear resist pattern was observed with a scanning electron microscope to measure the line width (CD), line width roughness (LWR), and number of defects (number of areas where the resist film was missing) of the resist pattern. Figure 13 is a graph showing the relationship between CD and EUV dose, Figure 14 is a graph showing the relationship between LWR and CD, and Figure 15 is a graph showing the relationship between the number of defects and CD. From these results, it was confirmed that the UV flood exposure after EUV exposure improves the margin of EUV exposure in terms of CD, LWR, and number of defects.

[0065] Test 5 The photoresist composition was applied onto an underlayer film formed on a silicon wafer using a spin coater. The coating was heated at 100°C for 60 seconds to remove the solvent, forming a resist film with a thickness of 22 nm. The resist film was exposed to EUV through a mask having a pattern corresponding to a plurality of pillars arranged at intervals of 36 nm. A plurality of resist films with different EUV doses were prepared. After exposure, the resist film was baked by heating at 160°C for 60 seconds. The entire surface of the baked resist film was exposed in one go to a KrF excimer laser. The dose of the KrF excimer laser was 50 mJ / cm. 2 The resist film after the floodwise exposure with the KrF excimer laser was developed with deionized water (DIW). The resist film after the same EUV exposure as above was baked by heating at 160° C. for 60 seconds without being subjected to full-scale exposure with a KrF excimer laser. The baked resist film was developed with deionized water. After the development process, the width (CD) of the formed pillar was measured by observing the linear resist pattern with a scanning electron microscope. Figure 16 is a graph showing the relationship between CD and EUV dose. It was confirmed that even when the developer is deionized water, it is possible to form a pattern by development while maintaining a high latitude of EUV exposure.

[0066] Test Example 6 The photoresist composition was applied onto an underlayer film formed on a silicon wafer using a spin coater. The coating was heated at 100°C for 60 seconds to remove the solvent, forming a resist film with a thickness of 22 nm. The resist film was exposed to a KrF excimer laser at a dose of 0 J / cm. 2 (without exposure) to 46 J / cm 2By exposing multiple areas while sequentially changing the exposure dose from 100 to 200, multiple resist films containing areas with different doses of KrF excimer laser were prepared. After exposure, the resist film was baked by heating at 210°C for 60 seconds. The entire surface of the baked resist film was then exposed to ultraviolet light with a wavelength of 280 nm in a single pass. The resist film after the single pass exposure was developed using TMAH. The resist film (resist pattern) after the development process was baked by heating at 250°C for 60 seconds. The thickness of the resist film (with PDB) remaining after baking was measured. After development, the thickness of the resist film (w / o PDB) that was not baked was also measured. Figure 17 is a graph showing the relationship between the thickness of the resist film remaining after development and the dose of the KrF excimer laser. It was confirmed that post-baking after development further reduces the remaining resist film in areas where the dose of the pattern exposure by the KrF excimer laser was small. It is believed that the remaining resist film also tends to reduce in the case of pattern exposure by EUV.

[0067] The present disclosure includes at least the following aspects. [1] irradiating a portion of a resist film including a metal oxide resist material with extreme ultraviolet light; irradiating an entire region of the resist film, including the portion irradiated with the extreme ultraviolet light and other portions, with ultraviolet light having a wavelength of 100 nm or more; forming a resist pattern by developing the resist film by removing a portion of the resist film; In this order: A method for forming a resist pattern. [2] The method according to [1], further comprising baking the resist film after the extreme ultraviolet radiation and before the ultraviolet radiation. [3] The method according to [1] or [2], further comprising baking the resist pattern formed by the developing. [4] the extreme ultraviolet ray is irradiated onto a portion of the resist film formed on the underlayer film; The method according to any one of [1] to [3], wherein the underlayer film is a film containing a silicon-containing material that contains silicon atoms and carbon atoms bonded to the silicon atoms. [5] the developing is wet developing including contacting the resist film with a developer, and the developer is an aqueous tetramethylammonium hydroxide solution or water; The method according to any one of [1] to [4]. [6] The method according to any one of [1] to [4], wherein the development is dry development comprising exposing the resist film to a developing gas. [7] The method according to [6], wherein the developing gas is an acidic gas. [8] 1. A method for manufacturing a semiconductor device having a patterned film, the method comprising: forming a resist pattern on an underlayer film, the resist pattern having an opening through which the underlayer film is exposed, by a method according to any one of [1] to [7]; etching the underlayer film exposed in the opening, thereby patterning the underlayer film; A method comprising: [9] a heat treatment unit for baking a resist film formed on a workpiece having an underlayer film; an exposure unit that irradiates ultraviolet light having a wavelength of 100 nm or more onto the resist film having a portion irradiated with extreme ultraviolet light; a developing unit for forming a resist pattern by developing the resist film by removing a portion of the resist film; a control unit that controls the exposure unit so that the ultraviolet light is irradiated onto an entire region of the resist film, including the portion irradiated with the extreme ultraviolet light and the other portion; Equipped with Substrate processing equipment.

[10] A computer-readable storage medium storing a program for causing an apparatus to execute the method according to claim 1. [Explanation of symbols]

[0068] 1...semiconductor wafer, 3...underlayer film, 3A...patterned underlayer film, 3a, 5a...trench, 5...resist film, 5A...resist pattern, 5E...portion of resist film irradiated with extreme ultraviolet light, 7...mask, R1...extreme ultraviolet light, R2...ultraviolet light, 11, 12, 13, 14...processing module, 20...substrate processing device, 24...carrier block, 25...processing block, 26...interface block, 30...exposure device, 40...exposure unit, 41...housing, 42...transport port, 50...movement mechanism, 51...support, 52...support stand, 53...rotating part, 54...mounting stand, 60...light source module, 61...housing, 62...light source, 63...shutter, 64...shutter movement mechanism, 100...control device, C...carrier, W...work, U1, U2...processing unit.

Claims

1. irradiating a portion of a resist film including a metal oxide resist material with extreme ultraviolet light; irradiating an entire region of the resist film, including the portion irradiated with the extreme ultraviolet light and other portions, with ultraviolet light having a wavelength of 100 nm or more; forming a resist pattern by developing the resist film by removing a portion of the resist film; In this order: A method for forming a resist pattern.

2. The method of claim 1 , further comprising baking the resist film after the extreme ultraviolet radiation and before the ultraviolet radiation is irradiated.

3. 3. The method of claim 2, further comprising baking the resist pattern formed by the developing.

4. the extreme ultraviolet ray is irradiated onto a portion of the resist film formed on the underlayer film; The method of claim 1 , wherein the underlayer film is a film comprising a silicon-containing material that includes silicon atoms and carbon atoms bonded to the silicon atoms.

5. the developing is wet developing including contacting the resist film with a developer, and the developer is an aqueous tetramethylammonium hydroxide solution or water; The method of claim 1.

6. 2. The method of claim 1, wherein the developing is a dry developing comprising exposing the resist film to a developing gas.

7. 7. The method of claim 6, wherein the developing gas is an acid gas.

8. 1. A method for manufacturing a semiconductor device having a patterned film, the method comprising: forming a resist pattern on an underlayer film by the method of claim 1, the resist pattern having an opening through which the underlayer film is exposed; etching the underlayer film exposed in the opening, thereby patterning the underlayer film; A method comprising:

9. a heat treatment unit for baking a resist film formed on a workpiece having an underlayer film; an exposure unit that irradiates the resist film having a portion irradiated with extreme ultraviolet light with ultraviolet light having a wavelength of 100 nm or more; a developing unit for forming a resist pattern by developing the resist film by removing a portion of the resist film; a control unit that controls the exposure unit so that the ultraviolet light is irradiated onto an entire region of the resist film, including the portion irradiated with the extreme ultraviolet light and other portions of the resist film; Equipped with Substrate processing equipment.

10. A computer-readable storage medium storing a program for causing an apparatus to execute the method according to claim 1.

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