Pattern forming method, resist material and pattern forming device

Abstract

To provide a method for forming a fine pattern having high contrast on a resist film.SOLUTION: There is provided a pattern forming method which comprises a step of applying a resist material on a substrate to form a resist film, a step of introducing a metal into the resist film, an exposure step and a development step. In addition, there are provided a resist material and a pattern forming device.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a pattern forming method, a resist material, and a pattern forming apparatus. [Background technology]

[0002] Electronic devices such as semiconductors are required to have higher definition through miniaturization. In addition, diversification of shapes of semiconductor device patterns is also being considered. As a method for forming such a pattern, for example, a lithography method using a photoresist is known. In the lithography method using a photoresist, a resist film is formed on a semiconductor substrate such as a silicon wafer, and the resist film is irradiated with electromagnetic waves such as ultraviolet rays through a photomask on which a semiconductor device pattern is drawn, and developed, and the substrate is etched using the photoresist pattern obtained as a protective film, whereby fine irregularities corresponding to the pattern can be formed on the substrate.

[0003] For example, Patent Document 1 discloses a method for forming a pattern by spin-coating a solution containing an α-methylstyrene-α-chloroacrylic acid ester copolymer onto a substrate, pre-baking, exposing to an electron beam, and developing. Patent Document 2 discloses a method for forming a radiation-patternable coating. Specifically, Patent Document 2 discloses a method for forming a coating, comprising depositing a coating solution containing an organic solvent, a first organometallic composition, and a metal compound having a hydrolyzable ligand-metal bond onto a substrate, and further exposing the precursor coating on the substrate to water.

[0004] Patent Document 3 discloses a pattern formation method including a film formation step and a contact step of contacting a pattern formation material film with a metal compound containing a metal element. Here, the film formation step includes a step of forming a film containing a pattern formation material, a step of irradiating a first region of the film with electromagnetic waves, and a step of removing the first region, and these steps are followed by a contact step of contacting with a metal compound containing a metal element. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 63-137227 [Patent Document 2] Special Publication No. 2019-500490 [Patent Document 3] JP 2019-53228 A Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, in the lithography method using a photoresist, a method for forming a fine pattern has been considered. However, in the conventional pattern formation method, the contrast after the pattern formation of the resist material may be low in some cases, and an improvement has been required.

[0007] In order to solve such problems of the conventional technology, the present inventors have carried out studies with the aim of providing a method for forming a fine pattern with high contrast in a resist film. [Means for solving the problem]

[0008] As a result of intensive research to solve the above problems, the inventors have found that the contrast of a resist film can be increased by providing a process of introducing a metal into the resist film between the process of applying a resist material onto a substrate to form a resist film and the process of exposing the resist film, and have thus completed the present invention. Specifically, the present invention has the following configuration.

[0009] [1] A step of applying a resist material onto a substrate to form a resist film; introducing a metal into the resist film; An exposure process; A developing step. [2] The method for forming a pattern according to [1], wherein the resist material contains a polymer, and the polymer contains a unit derived from at least one selected from the structures represented by the following general formulas (101) to (103): [ka] [ka] [ka] In general formula (101), R 1 each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted acyl group, an optionally substituted allyl group, an optionally substituted alkoxy group, or an optionally substituted alkylsilyl group, 1 may be the same or different; R 11 represents a hydrogen atom or an alkyl group which may have a substituent; R 2 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or a halogenated alkyl group; Y 1 represents a single bond or a linking group; In general formula (102), X 1 represents an optionally substituted alkyl group, an optionally substituted acyl group, or an optionally substituted allyl group; R 3 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or a halogenated alkyl group; Y 2 represents a single bond or a linking group; In general formula (103), X 2 represents an optionally substituted aryl group; R 4 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or a halogenated alkyl group; Y 3 represents a single bond or a linking group. [3] The method for forming a pattern according to [2], wherein the polymer contains units derived from structures represented by general formulae (101) to (103). [4] R2 ~R 4 At least one of the above is a fluorine atom, a chlorine atom or a bromine atom. [5] The pattern formation method according to any one of [1] to [4], wherein the step of introducing a metal is a step of introducing at least one selected from the group consisting of Mg, Al, Ag, Ge, Cd, W, Ta, Hf, Zr, Mo, In, Sn, Sb and Te. [6] The pattern formation method according to any one of [1] to [5], wherein in the step of introducing a metal, a metal material in which at least one selected from a halogen, an alkyl group, and an aminoalkyl group is bonded to a metal element is used. [7] A metal gas material for use in the pattern formation method according to any one of [1] to [6], the metal gas material comprising at least one element selected from the group consisting of Mg, Al, Ag, Ge, Cd, W, Ta, Hf, Zr, Mo, In, Sn, Sb and Te. [8] The metal gas material according to [7], wherein the metal gas material is a material in which at least one selected from a halogen, an alkyl group, and an aminoalkyl group is bonded to a metal element. [9] A resist material for introducing a metal, comprising a polymer including a unit derived from at least one selected from the structures represented by the following general formulas (101) to (103): [ka] [ka] [ka] In general formula (101), R 1 each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted acyl group, an optionally substituted allyl group, an optionally substituted alkoxy group, or an optionally substituted alkylsilyl group, 1 may be the same or different; R 11represents a hydrogen atom or an alkyl group which may have a substituent; R 2 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or a halogenated alkyl group; Y 1 represents a single bond or a linking group; In general formula (102), X 1 represents an optionally substituted alkyl group, an optionally substituted acyl group, or an optionally substituted allyl group; R 3 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or a halogenated alkyl group; Y 2 represents a single bond or a linking group; In general formula (103), X 2 represents an optionally substituted aryl group; R 4 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or a halogenated alkyl group; Y 3 represents a single bond or a linking group.

[10] The resist material according to [9], wherein the polymer contains units derived from structures represented by general formulas (101) to (103).

[11] R 2 ~R 4 At least one of the above is a fluorine atom, a chlorine atom, or a bromine atom.

[12] A unit for applying a resist material onto a substrate to form a resist film; a unit for introducing a metal into the resist film; An exposure unit; a development unit. Effect of the Invention

[0010] According to the manufacturing method of the present invention, a high-contrast and fine pattern can be formed in the resist film. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view illustrating the configuration of a substrate and a resist film. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will be described in detail below. The following description of the constituent elements may be based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. In this specification, a numerical range expressed using "~" means a range including the numerical values ​​before and after "~" as the lower and upper limits.

[0013] (Pattern formation method) The present invention relates to a pattern forming method including a step of applying a resist material onto a substrate to form a resist film, a step of introducing a metal into the resist film, an exposure step, and a development step. The pattern forming method of the present invention includes a step of forming a resist film, a step of introducing a metal into the resist film, an exposure step, and a development step, in this order.

[0014] FIG. 1(a) shows a laminate in which a resist material is applied onto a substrate 10 and a resist film 40 is formed. Although not shown, another layer may be provided between the substrate 10 and the resist film 40. Then, in the state of the laminate in which the resist film 40 is formed on the substrate 10, a metal is introduced into the resist film 40. Then, as shown in FIG. 1(b), at least a part of the resist film 40 is removed so as to form a pattern shape to be formed on the substrate 10. For example, the resist film 40 is subjected to exposure and development treatment to form a pattern shape as shown in FIG. 1(b).

[0015] The pattern forming method of the present invention includes a step of introducing a metal into the resist film between the step of forming the resist film and the step of exposing. In the present invention, a high-contrast resist film can be formed by providing a step of introducing a metal into the resist film between the step of forming the resist film and the step of exposing. The contrast of the resist film can be evaluated as being high when the difference in resist pattern height before and after development is measured and the value of the height of the resist film before development minus the height of the resist film after development is small. In other words, when the change in resist height before and after development is small, the resist film can be evaluated as having high contrast.

[0016] Furthermore, the pattern forming method of the present invention can also improve the resolution of the resist film. The resolution can be evaluated as good when a resist film is formed to form a line-and-space pattern with a width of 100 nm, a desired pattern structure is formed, and there is no residue from the resist film in the space portion.

[0017] Furthermore, according to the pattern forming method of the present invention, a pattern with a high aspect ratio can be formed on a resist film. The aspect ratio of a resist film is a value calculated by dividing the height of the resist film by the width of the resist film in the line portion of a line-and-space pattern formed on the resist film. In the present specification, the pattern shape is observed in a state where the theoretical aspect value is obtained, and if the pattern is linear, the aspect ratio can be evaluated as being high.

[0018] In the pattern forming method of the present invention, the resist material used to form the resist film does not contain a metal component, and the metal is introduced after the resist film is formed. This can further increase the stability of the resist material. In addition, in the pattern forming method of the present invention, the metal is introduced at a stage before a pattern shape is formed in the resist film. This can more effectively increase the contrast of the patterning of the resist film.

[0019] <Step of forming resist film> Substrates used in the pattern formation method include, for example, glass, silicon, SiN, GaN, AlN, etc. Substrates made of organic materials such as PET, PE, PEO, PS, cycloolefin polymer, polylactic acid, and cellulose nanofiber may also be used.

[0020] Before applying the resist material to the substrate, it is preferable to provide a process of washing the substrate. By washing the substrate surface, the coating property of the resist material is improved. As the washing treatment method, a conventionally known method can be used, for example, oxygen plasma treatment, ozone oxidation treatment, acid-alkali treatment, chemical modification treatment, etc.

[0021] The method for applying the resist material is not particularly limited, but for example, the resist material can be applied to the substrate by a known method such as a spin coating method. For example, a spin method, a spray method, a method of coating the area to be coated at once using a dispenser, an inkjet method, etc. can be adopted. Among them, the method for applying the resist material is preferably a spin method.

[0022] After the resist material is applied, the resist material may be hardened by heating to form a resist film. In particular, when the resist material is applied by spin coating, the solvent in the resist material can be removed in a short time by providing a heating step. The temperature when the coating film is heated is not particularly limited, but is preferably 60°C or higher and 550°C or lower. In addition, the heat treatment is preferably a heat treatment in the atmosphere and at a relatively low temperature. The heating method is not particularly limited, but a method using a hot plate, a method of irradiating infrared rays, etc. can be adopted. Among them, the method using a hot plate is simple and preferable. In addition, the atmosphere during heating can be in the atmosphere, in an inert gas such as nitrogen, or in a vacuum. The heating time is not particularly limited, but is preferably 0.3 minutes or more and 10 minutes or less.

[0023] The substrate and the resist film are preferably laminated in this order so that adjacent layers are in direct contact with each other, but other layers may be provided between each layer. For example, an anchor layer may be provided between the substrate and the resist film. The anchor layer is a layer that controls the wettability of the substrate and enhances the adhesion between the substrate and the resist film. An anti-reflection film may be provided between the substrate and the resist film. Note that a plurality of layers made of different materials may be sandwiched between the substrate and the resist film. These materials are not particularly specified, but may include inorganic materials such as SiO2, SiN, Al2O3, AlN, GaN, GaAs, W, Cr, Ru, Ta, TaN, SOG, and amorphous carbon, and organic materials such as commercially available SOC and adhesives.

[0024] <Metal introduction process> The pattern forming method of the present invention further includes a metal introduction step between the step of forming a resist film and the step of exposing. In this case, the metal introduction step can be a step of introducing a metal into the resist film, such as the SIS method (Sequential Infiltration Synthesis). Examples of the metal to be introduced include Li, Be, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ru, Pd, Ag, Cd, In, Sn, Sb, Te, Cs, Ba, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Among them, the metal to be introduced is preferably at least one selected from the group consisting of Mg, Al, Ag, Ge, Cd, W, Ta, Hf, Zr, Mo, In, Sn, Sb and Te, more preferably at least one selected from the group consisting of Sn, Sb and Te. Such a process can be carried out, for example, by the method described in Journal of Photopolymer Science and Technology Volume 29, Number 5 (2016) 653-657.

[0025] In the step of introducing the metal, it is preferable to adopt a method of introducing the metal by permeating a metal gas into the resist film, a method of introducing the metal by injecting metal ions into the resist film using an ion implantation method, or a method of introducing the metal by applying a solution containing the metal onto the resist film and reacting it with the material. Among them, the method of permeating a metal gas into the resist film is particularly preferable because the metal easily permeates into the inside of the resist film and the components in the resist film and the metal form bonds by chemical reaction.

[0026] In the method of permeating the metal gas into the resist, it is preferable to fill the vacuum chamber with the metal gas after placing the substrate on which the resist film is formed in a vacuum chamber to create a vacuum condition. It is preferable to keep the metal gas filled in the vacuum chamber for a certain period of time. After the reaction, the vacuum chamber is returned to normal pressure and the substrate on which the resist film is formed is taken out. After the metal gas is introduced into the resist film, water vapor or ozone may be brought into contact with the resist film. The above process is regarded as one cycle, and the process of permeating the metal gas into the resist may be performed 1 to 100 cycles. It is preferable to perform the process of permeating the metal gas into the resist once, since the process time can be shortened. On the other hand, it is preferable to perform the process of permeating the metal gas into the resist multiple times, since the metal can be further introduced into the resist film.

[0027] A heating step may be provided after the step of introducing the metal. By heating, the penetration of the metal into the resist film can be promoted. The heating method is not particularly limited, but examples thereof include a hot plate, irradiation with a laser such as infrared light, and irradiation with a xenon flash lamp.

[0028] The metal gas used in the step of introducing a metal may be, for example, a metal gas in which a halogen, an alkoxy group, an alkyl group, or an aminoalkyl group is bonded to a metal element. For example, magnesium chloride, aluminum chloride, silver chloride, germanium chloride, cadmium chloride, tungsten chloride, tantalum chloride, hafnium chloride, indium chloride, tin chloride, antimony chloride, tellurium chloride, molybdenum chloride, tetrakisdimethylaminohafnium, tetramethoxyhafnium, trimethylaluminum, bisdiisopropylpropionamidinate-cobalt, diisopropylpropionamidinate-copper, tetratridimethylaminotitanium, dimethyltellurium, diethyltellurium, di(isopropyl)tellurium, di(isopropyl)ditellurium, tri(isopropyl)antimony, tetramethyltin, tetrakisdi Examples of the metal gas include methylaminotin, tri(isobutyl)indium, tri(isobutyl)gallium, pentakisdimethylaminotantalum, bisacetylacetonatomagnesium, tetraethoxygermanium, tetraethylgermanium, tetramethoxygermanium, dimethylcadmium, tetraisoproxyzirconium, tetrakisdimethylamidozirconium, bismethylcyclopentadienylmethoxymethylzirconium, bismethylcyclopentadienyldimethylhafnium, bis(t-butylimino)bis(dimethylamino)molybdenum, and bis(t-butylimino)bis(dimethylamino)tungsten. Among them, metal gases in which at least one selected from halogen, alkyl group, and aminoalkyl group is bonded to a metal element are preferred because of their high reactivity. These metal gases can be applied by using their vapor even if they are liquid or solid at room temperature. To generate vapor, the metal gas material can also be heated.

[0029] The present invention may be an invention relating to a metal gas material used in the step of introducing a metal in a pattern formation method, the metal gas material including at least one selected from the group consisting of Mg, Al, Ag, Ge, Cd, W, Ta, Hf, Zr, Mo, In, Sn, Sb, and Te. It is particularly preferable that such a metal gas material is a material in which at least one selected from a halogen, an alkyl group, and an aminoalkyl group is bonded to a metal element.

[0030] The metal solution used in the step of introducing a metal is not particularly limited, but examples thereof include a ferrocene solution, a tellurium tetrachloride solution, a tin acetate solution, a copper acetylacetonate solution, an indium iodide solution, a hexaneamine cobalt chloride solution, an ethylenediamine zirconium tetraacetate solution, and an ethylenediamine copper tetraacetate solution. The solvent used in the metal solution is not particularly limited, but water or an organic solvent can be used. Among them, the solvent is preferably ethanol, isopropyl alcohol, acetonitrile, ethyl acetate, or the like.

[0031] In the step of introducing a metal, when a metal gas is introduced, the temperature of the substrate is preferably 0 to 400°C, more preferably 20 to 300°C. In addition, the pressure in the chamber when introducing the metal gas is preferably 100 kPa or less in order to facilitate the penetration of the gas. In addition, plasma can be irradiated into the chamber when the metal gas is introduced. By irradiating the plasma, it is possible to further activate the metal gas. For example, as disclosed in JP 2019-54062 A, a method of irradiating the plasma with argon gas and introducing the metal gas can be used.

[0032] <Exposure process> The exposure step is a step of irradiating the resist film after the introduction of metal with electromagnetic waves in order to form an arbitrary pattern. The electromagnetic waves are not particularly limited, but semiconductor lasers, high pressure mercury lamps such as g-line and i-line, excimer lasers such as ArF and KrF, electron beams, extreme ultraviolet rays, X-rays, etc. can be used. In particular, when electron beams or extreme ultraviolet rays are used, the method of the present invention can be used to reduce the decrease in the resist film thickness. Furthermore, the effect of the introduction of metals can also be obtained, which makes it easier to inspect the fine pattern structure. After the exposure, post exposure bake can be performed as necessary. The post exposure bake is preferably performed under conditions of a heating temperature of 70°C to 150°C and a heating time of 0.3 to 10 minutes.

[0033] In the exposure step, exposure may be performed through a photomask on which an arbitrary pattern is formed, or may be directly written using an electron beam laser or the like. For example, by irradiating a predetermined electromagnetic wave through a mask on which a circuit pattern is drawn, the resist film in the light-hit portion is altered to transfer the mask pattern. At this time, it is preferable that the main chain of the polymer contained in the resist film is cut in the light-hit portion. In the exposed portion, the main chain of the polymer is cut, and in the subsequent development step, the cut polymer is dissolved in a developer, and the exposed portion of the resist film (resist material) is removed. In this way, an intermittent portion is formed in the resist film in the exposed portion, and the substrate 10 is exposed in the intermittent portion of the resist film.

[0034] When the resist film is irradiated with electromagnetic waves in the exposure step, the wavelength of the electromagnetic waves is not particularly limited, but is preferably 15 nm or less.

[0035] <Developing process> The development step is a step of exposing the resist film to light and then contacting it with a developer to form a pattern. The development method is not particularly limited, but can be a dipping method or a spin coating method. The development temperature can be room temperature or can be changed as appropriate. The developer used in the development step is not particularly limited, but can be a known developer. For example, examples include aromatics such as xylene, toluene, and anisole; esters such as pentyl acetate, hexyl acetate, heptyl acetate, octyl acetate, ethyl acetate, propyl acetate, n-butyl acetate, ethyl lactate, propyl lactate, butyl lactate, and gamma-butyrolactone; alcohols such as ethanol and isopropanol; ketones such as diethyl ketone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethers such as diethylene glycol dimethyl ether; organic acids such as acetic anhydride and acetic acid; aqueous solutions of alkali metal hydroxides such as potassium hydroxide and sodium hydroxide; aqueous solutions of quaternary ammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and choline; and aqueous solutions of amines such as ethanolamine, propylamine, and ethylenediamine. In the development step, these developers can be mixed and used. Furthermore, a surfactant can be added to these developers. The development conditions are appropriately selected from a temperature of -70 to 50°C and a time of 1 to 300 seconds.

[0036] In addition, a rinsing step using a rinsing liquid may be performed after the development step. The rinsing liquid is not particularly limited, but any known rinsing liquid may be used. For example, xylene, butyl acetate, ethanol, isopropyl alcohol, methyl isobutyl ketone, pure water, etc. may be used. As the rinsing liquid, each of these may be used alone or in combination of two or more. Furthermore, a surfactant may be added to these rinsing liquids. The conditions for the rinsing step are appropriately selected from a temperature of -70 to 50°C and a time of 10 to 100 seconds.

[0037] <Other processes> The pattern forming method of the present invention is a method for forming a pattern on a resist film formed from a resist material, but may further include a step of processing a semiconductor substrate or the like using the pattern formed on the resist film as a protective film. Such a step is called an etching step. In this case, the etching step is provided as a post-step of the development step.

[0038] Examples of methods for processing the semiconductor substrate in the etching step include known methods such as chemical wet etching (wet development), reactive ion etching (RIE) such as chemical dry etching, sputter etching, physical etching such as ion beam etching, etc. The processing of the semiconductor substrate is preferably performed by dry etching using a gas such as tetrafluoromethane, perfluorocyclobutane (C4F8), perfluoropropane (C3F8), trifluoromethane, carbon monoxide, argon, oxygen, nitrogen, chlorine, sulfur hexafluoride, difluoromethane, nitrogen trifluoride, and chlorine trifluoride.

[0039] (Pattern forming device) The present invention may relate to a pattern forming apparatus including a unit for applying a resist material onto a substrate to form a resist film, a unit for introducing a metal into the resist film, an exposure unit, and a development unit. The pattern forming apparatus of the present invention has the above units, but may be an apparatus in which each of the units has a single function. For example, the apparatus may be an apparatus in which the unit for forming a resist film and the unit for introducing a metal into the resist film are integrated into one unit, or an apparatus in which the step of introducing a metal and the step of exposing are integrated into one unit. It is preferable that the pattern forming apparatus is an apparatus in which these units are connected by a transport means and a series of steps can be performed.

[0040] The unit for forming the resist film includes a supplying means for supplying the resist material onto the substrate. Examples of the supplying means include a spin coater, a spray coater, a dispenser, an inkjet coater, etc. Among them, the supplying means is preferably a spin coater.

[0041] The unit for forming the resist film may further include a heating means. Examples of the heating means include a hot plate and an infrared laser irradiation device. When the unit for forming the resist film includes a heating means, the heating means may be configured to be located next to the supplying means. In addition, a space may be provided between the supplying means and the heating means to allow the substrate to retreat, and the substrate may be transported to perform the treatment.

[0042] The unit for introducing metal into the resist film includes a chamber and a means for supplying metal gas into the chamber. That is, a metal gas supply pipe may be connected to the chamber. The chamber is preferably a vacuum chamber, and is particularly preferably equipped with a vacuum pump. After the resist film is placed in such a chamber, metal gas is supplied into the chamber and filled with the metal gas, so that the metal gas can be brought into contact with the resist film, thereby introducing metal into the resist film. The container for storing the metal gas may be equipped with a heating device, and the metal gas supply pipe may also be equipped with a heating device.

[0043] The chamber may further include a means for heating the resist film. For example, a hot plate may be installed in the chamber. The heating means such as a hot plate may be set to a desired temperature in advance, or may be set to introduce the metal while changing the temperature.

[0044] A spin coater, for example, can be used as the unit for introducing a metal into the resist film. The atmosphere of the unit for introducing a metal into the resist film may be air, an inert gas atmosphere such as nitrogen, or a vacuum. In particular, an inert gas atmosphere is preferable because it allows the use of a highly reactive metal solution.

[0045] The exposure unit includes an electromagnetic wave irradiation section. Examples of the electromagnetic wave irradiation section include semiconductor lasers, high-pressure mercury lamps such as g-rays and i-rays, excimer lasers such as ArF and KrF, electron beams, extreme ultraviolet rays, and electromagnetic wave irradiation devices such as X-rays. Examples of the exposure unit include units including an optical section, an electromagnetic wave irradiation section, and a power supply section. When a photomask is used in the exposure process, the exposure unit may be provided with a section for installing the photomask. When an exposure method using a photomask is adopted, for example, a process called step exposure may be adopted. In step exposure, a substrate having a resist film is transported into a chamber, and electromagnetic waves are irradiated from above through a photomask on which a desired pattern has been processed, and a certain area is exposed under conditions that optimize the amount of irradiation, time, focus, and the like. This is repeated multiple times to expose the entire surface of the wafer. In addition, in an exposure method that does not use a photomask, for example, after adjusting the focus and dose amount so that the electromagnetic waves are irradiated on the surface of the resist film, exposure is performed at an arbitrary position to form a desired pattern. In addition, a method called immersion exposure can be adopted when exposing. Immersion exposure is a method in which water, oil, or the like is placed on a resist film and electromagnetic waves are irradiated through this to form finer patterns.

[0046] The developing unit preferably includes a developer storage tank, a spin coater, and a developer supply pipe. In the developing unit, a developer is applied from the developer supply pipe onto the resist film after exposure to develop the resist film, and then the substrate having the resist film is rotated by the spin coater to remove the developer. The developing unit may further include a rinse liquid storage tank and a rinse liquid pipe. A method may also be adopted in which a rinse liquid is applied onto the resist film after removing the developer, and the substrate having the resist film is rotated by the spin coater to remove the rinse liquid.

[0047] (Resist material) The resist material used in the pattern forming method of the present invention preferably contains a polymer. In particular, the polymer is preferably a main chain scission type positive resist material (polymer). The main chain of the polymer contained in the resist material is scissed by irradiation with an electron beam, and only the exposed portion dissolves in a developer. This makes it possible to form a more precise pattern.

[0048] In the pattern formation method of the present invention, a metal is introduced into a resist film formed from a resist material, and thus the resist material is preferably a resist material for introducing a metal.

[0049] The resist material used in the pattern forming method of the present invention preferably contains a polymer, and more preferably the polymer contains a unit derived from at least one selected from the structures represented by the following general formulas (101) to (103). For example, the polymer may contain a unit derived from the structure represented by the following general formula (101), may contain a unit derived from the structure represented by the following general formula (102), or may contain a unit derived from the structure represented by the following general formula (103). In addition, the polymer preferably contains a unit derived from the structures represented by the following general formulas (101) and (102), preferably contains a unit derived from the structures represented by the following general formulas (101) and (103), and preferably contains a unit derived from the structures represented by the following general formulas (102) and (103). Among them, it is particularly preferable that the polymer contains all the units derived from the structures represented by the following general formulas (101) to (103). In this specification, the term "unit" refers to a repeating unit (monomer unit) constituting the main chain of the polymer. In addition, when a polymer contains units derived from a sugar derivative, the side chain of a unit derived from one sugar derivative may further contain a unit derived from a sugar derivative, in which case the repeating unit (monomer unit) constituting the side chain polymer also corresponds to the "unit" as used in this specification. [ka] [ka] [ka]

[0050] In general formula (101), R 1 each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted acyl group, an optionally substituted allyl group, an optionally substituted alkoxy group, or an optionally substituted alkylsilyl group, 1 may be the same or different. 11R represents a hydrogen atom or an alkyl group which may have a substituent. 2 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or a halogenated alkyl group; Y 1 represents a single bond or a linking group. In general formula (102), X 1 R represents an alkyl group which may have a substituent, an acyl group which may have a substituent, or an allyl group which may have a substituent. 3 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or a halogenated alkyl group; Y 2 represents a single bond or a linking group. In general formula (103), X 2 R represents an aryl group which may have a substituent. 4 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or a halogenated alkyl group; Y 3 represents a single bond or a linking group.

[0051] In particular, the polymer contained in the resist material preferably contains a unit derived from the structure represented by general formula (101) above.

[0052] In general formula (101), R 1 each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted acyl group, an optionally substituted allyl group, an optionally substituted alkoxy group, or an optionally substituted alkylsilyl group. Here, the optionally substituted alkyl group includes a sugar derivative group, and R 1 may be a unit derived from a linear or branched chain sugar derivative. The unit derived from a linear or branched chain sugar derivative is preferably a sugar derivative having the same structure as the sugar derivative to which it is bound. 1 is a unit derived from a linear or branched sugar derivative, the number of linked sugar derivative groups (average degree of polymerization of the sugar derivative) is preferably 15 or less, more preferably 10 or less.

[0053] Among them, R 1are each preferably independently a hydrogen atom, an optionally substituted alkyl group, or an optionally substituted acyl group, and R 1 R is preferably a hydrogen atom or an acyl group which may have a substituent, and more preferably an acyl group which may have a substituent. 1 When is an acyl group which may have a substituent, the resolution of the resist material can be more effectively increased, and the contrast of the resist film can also be increased.

[0054] R 1 When is an alkyl group or an acyl group, the number of carbon atoms can be appropriately selected depending on the purpose. For example, the number of carbon atoms is preferably 1 or more, and is preferably 200 or less, more preferably 100 or less, even more preferably 20 or less, and particularly preferably 4 or less.

[0055] R 1 Specific examples of the alkyl group include acyl groups such as acetyl, propanoyl, butyryl, isobutyryl, valeryl, isovaleryl, pivaloyl, hexanoyl, octanoyl, chloroacetyl, trifluoroacetyl, cyclopentanecarbonyl, cyclohexanecarbonyl, benzoyl, methoxybenzoyl, and chlorobenzoyl; and alkyl groups such as methyl, ethyl, n-propyl, n-butyl, i-butyl, and t-butyl. Among these, methyl, ethyl, acetyl, propanoyl, n-butyryl, isobutyryl, benzoyl, and trimethylsilyl groups are preferred, and acetyl and propanoyl groups are particularly preferred.

[0056] In general formula (101), R 11 R represents a hydrogen atom or an alkyl group which may have a substituent. 11 When R represents an alkyl group which may have a substituent, examples of the alkyl group include a methyl group, an ethyl group, and a propyl group. 11In the case of R, the alkyl group is preferably a methyl group, and such an alkyl group preferably further has a substituent. Examples of the substituent that the alkyl group has include a hydroxyl group, an acyl group, an allyl group, and an alkoxy group, and among these, the substituent is preferably a hydroxyl group or an acyl group. More specifically, R 11 When R represents an alkyl group which may have a substituent, 11 -CH2OR 1 Preferably, R 1 The above-mentioned groups can be mentioned as examples of R 11 It is particularly preferred that R is a hydrogen atom. 11 By making the atom a hydrogen atom, it becomes easier to form a finer pattern structure.

[0057] In general formula (101), R 2 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom, or a halogenated alkyl group. 2 R is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a fluorine atom, a chlorine atom or a bromine atom, and particularly preferably a fluorine atom, a chlorine atom or a bromine atom. 2 By introducing fluorine, chlorine or bromine atoms into the resist film, the contrast of the resist film formed can be made higher.

[0058] In general formula (101), Y 1 Each independently represents a single bond or a linking group. Y 1 When is a linking group, Y 1 Examples of Y include linking groups that do not contain a sugar unit, such as groups containing an alkylene group, a phenylene group, -O-, -C(=O)O-, etc. 1 may be a linking group combining these groups. 1 is preferably a linking group represented by the following structural formula: [ka]

[0059] In the above structural formula, the * symbol indicates the bonding site with the main chain, and the * symbol indicates the bonding site with the sugar unit of the side chain.

[0060] In the above general formula (101), the structure of the sugar derivative is described as a cyclic structure, but the structure of the sugar derivative may be not only a cyclic structure but also an open-ring structure (chain structure) called an aldose or ketose.

[0061] The polymer contained in the resist material preferably contains a unit derived from the structure represented by general formula (102) above, and more preferably contains a unit derived from the structure represented by general formula (102) above, in addition to the unit derived from the structure represented by general formula (101) above.

[0062] In general formula (102), X 1represents an alkyl group which may have a substituent, an acyl group which may have a substituent, or an allyl group which may have a substituent, and is preferably an alkyl group which may have a substituent. The number of carbon atoms in the alkyl group is preferably 1 to 8, more preferably 1 to 5, and even more preferably 1 to 3. The above carbon number is the number of carbon atoms excluding the substituent. Examples of the alkyl group having a substituent include, for example, -CH2-OH, -CH2-O-methyl, -CH2-O-ethyl, -CH2-On-propyl, -CH2-O-isopropyl, -CH2-On-butyl, -CH2-O-isobutyl, -CH2-Ot-butyl, -CH2-O-(C=O)-methyl, -CH2-O-(C=O)-ethyl, -CH2-O-(C=O)-propyl, -CH2-O-(C=O)-isopropyl, -CH2-O-(C=O)-n-butyl, -CH2-O-(C=O)-isobutyl, -CH2-O-(C=O)-t-butyl, -C2H4-OH, -C2H4-O- Examples of the alkyl group include methyl, -C2H4-O-ethyl, -C2H4-On-propyl, -C2H4-O-isopropyl, -C2H4-On-butyl, -C2H4-O-isobutyl, -C2H4-Ot-butyl, -C2H4-O-(C=O)-methyl, -C2H4-O-(C=O)-ethyl, -C2H4-O-(C=O)-n-propyl, -C2H4-O-(C=O)-isopropyl, -C2H4-O-(C=O)-n-butyl, -C2H4-O-(C=O)-isobutyl, -C2H4-O-(C=O)-t-butyl, -C2H4-O-(C=O)-CH2-(C=O)-methyl, etc. The alkyl group having a substituent may be a cycloalkyl group or a bridged cyclic cycloalkyl group.

[0063] In general formula (102), R 3 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom, or a halogenated alkyl group. 3 R is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a fluorine atom, a chlorine atom or a bromine atom, and particularly preferably a fluorine atom, a chlorine atom or a bromine atom. 3By introducing a fluorine atom, a chlorine atom, or a bromine atom into the R in the general formula (101), the contrast of the formed resist film can be increased. 2 and R in general formula (102) 3 At least one of R in the general formula (101) is preferably a fluorine atom, a chlorine atom, or a bromine atom. 2 and R in general formula (102) 3 may both be fluorine atoms, chlorine atoms or bromine atoms.

[0064] In general formula (102), Y 2 represents a single bond or a linking group. 2 When is a linking group, Y 2 Examples of Y include groups containing an alkylene group, a phenylene group, -O-, -C(=O)O-, etc. 2 may be a linking group combining these groups. 2 is preferably a linking group represented by the following structural formula: [ka]

[0065] In the above structural formula, the mark * indicates the bonding site with the main chain, and the mark * indicates X 1 represents the binding site with

[0066] The polymer contained in the resist material preferably contains a unit derived from the structure represented by the general formula (103) above, and more preferably contains a unit derived from the structure represented by the general formula (103) above in addition to the unit derived from the structure represented by the general formula (101) above. In particular, it is particularly preferable for the polymer to contain all of the units derived from the structures represented by the general formulae (101) to (103) above.

[0067] The polymer contained in the resist material preferably further contains a unit derived from the structure represented by the above general formula (103). When the polymer further contains a unit derived from the structure represented by the general formula (103), the solubility in organic solvents can be improved.

[0068] In general formula (103), X 2 represents an aryl group which may have a substituent. 2 is preferably a phenyl group.

[0069] In general formula (103), R 4 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom, or a halogenated alkyl group. 4 R is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a fluorine atom, a chlorine atom or a bromine atom, and particularly preferably a fluorine atom, a chlorine atom or a bromine atom. 4 By introducing fluorine, chlorine or bromine atoms into the resist film, the contrast of the resist film formed can be made higher.

[0070] In the general formulas (101) to (103), R 2 ~R 4 At least one of these is preferably a fluorine atom, a chlorine atom or a bromine atom.

[0071] In general formula (103), Y 3 represents a single bond or a linking group. 2 When is a linking group, Y 3 Examples of Y include groups containing an alkylene group, a phenylene group, -O-, -C(=O)O-, etc. 3 may be a linking group that is a combination of these groups. 3 is particularly preferably a single bond.

[0072] The unit derived from the structure represented by the general formula (103) is preferably a unit derived from a styrene compound. Examples of the styrene compound include styrene, o-methylstyrene, p-methylstyrene, ethylstyrene, p-methoxystyrene, p-phenylstyrene, 2,4-dimethylstyrene, pn-octylstyrene, pn-decylstyrene, pn-dodecylstyrene, chlorostyrene, bromostyrene, trimethylsilylstyrene, hydroxystyrene, 3,4,5-methoxystyrene, pentamethyldisilylstyrene, t-butoxycarbonylstyrene, tetrahydropyranylstyrene, phenoxyethylstyrene, and t-butoxycarbonylmethylstyrene.

[0073] When the polymer contains a unit derived from the structure represented by general formula (101), the content (mass%) of the unit derived from the structure represented by general formula (101) is preferably 1 mass% or more and 95 mass% or less, more preferably 3 mass% or more and 90 mass% or less, even more preferably 7 mass% or more and 85 mass% or less, and particularly preferably 12 mass% or more and 80 mass% or less, based on the total mass of the polymer. By setting the content of the unit derived from the structure represented by general formula (101) within the above range, the contrast of the resist film formed from the resist material can be more effectively increased.

[0074] The content of the unit derived from the structure represented by the general formula (101) is, for example, 1 It can be determined from H-NMR and the weight average molecular weight of the polymer. Specifically, it can be calculated using the following formula. Content (mass%) of units derived from the structure represented by the general formula (101) = mass of units derived from the structure represented by the general formula (101) × number of units (monomers) derived from the structure represented by the general formula (101) / weight average molecular weight of polymer

[0075] When the polymer contains a unit derived from the structure represented by general formula (102), the content (mass%) of the unit derived from the structure represented by general formula (102) is preferably 1 mass% or more and 99 mass% or less, more preferably 3 mass% or more and 98 mass% or less, and particularly preferably 12 mass% or more and 97 mass% or less, based on the total mass of the polymer. The content (mass%) of the unit derived from the structure represented by general formula (102) can be calculated in the same manner as the calculation of the content of the unit derived from the structure represented by general formula (101) described above.

[0076] When the polymer contains a unit derived from the structure represented by general formula (103), the content (mass%) of the unit derived from the structure represented by general formula (103) is preferably 1 mass% or more and 99 mass% or less, more preferably 3 mass% or more and 98 mass% or less, and particularly preferably 12 mass% or more and 97 mass% or less, based on the total mass of the polymer. The content (mass%) of the unit derived from the structure represented by general formula (103) can be calculated in the same manner as the calculation of the content of the unit derived from the structure represented by general formula (101) described above.

[0077] The polymer contained in the resist material preferably contains a unit derived from the structure represented by the general formula (101) described above, and further contains a unit derived from the structure represented by the general formula (102) and / or (103). When the polymer contains a unit derived from the structure represented by the general formula (102) and / or (103), the polymer becomes a copolymer. When the polymer is a copolymer, the copolymer may be a block copolymer or a random copolymer. Furthermore, the copolymer may have a structure in which a part is a random copolymer and a part is a block copolymer. In this way, an appropriate structure can be selected depending on the application and required physical properties.

[0078] The polymer may contain other units in addition to the units derived from the structures represented by the above general formulae (101) to (103). The other units are not particularly limited as long as they are polymerizable with the structures represented by the above general formulae (101) to (103).

[0079] The amount of the polymer is preferably 0.1% by mass or more, and more preferably 0.3% by mass or more, based on the total mass of the resist material, and is preferably 40% by mass or less, and more preferably 30% by mass or less, based on the total mass of the resist material.

[0080] The weight average molecular weight (Mw) of the polymer is preferably 500 or more, more preferably 1000 or more, and even more preferably 1500 or more. The weight average molecular weight (Mw) of the polymer is preferably 2 million or less, more preferably 1.5 million or less, even more preferably 1 million or less, and even more preferably 700,000 or less. The weight average molecular weight (Mw) of the polymer is a value measured in terms of polystyrene by GPC.

[0081] The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the polymer is preferably at least 1. Moreover, Mw / Mn is preferably at most 100, more preferably at most 50, even more preferably at most 20, still more preferably at most 15, and particularly preferably at most 10.

[0082] The solubility of the polymer in at least one selected from PGMEA, PGME, THF, butyl acetate, anisole, cyclohexanone, ethyl lactate, N-methylpyrrolidone, γ-butyrolactone, and DMF is preferably 1% by mass or more, more preferably 2% by mass or more, and particularly preferably 3% by mass or more. The upper limit of the solubility of the polymer in the organic solvent is not particularly limited, but can be, for example, 40% by mass. The solubility is the solubility in at least one selected from PGMEA, PGME, THF, butyl acetate, anisole, cyclohexanone, ethyl lactate, N-methylpyrrolidone, γ-butyrolactone, and DMF.

[0083] The solubility of a polymer is measured by gradually adding PGMEA, PGME, THF, butyl acetate, anisole, cyclohexanone, ethyl lactate, N-methylpyrrolidone, γ-butyrolactone or DMF to a given amount of polymer while stirring, and recording the amount of organic solvent added when the polymer is dissolved. A magnetic stirrer or the like may be used for stirring. The solubility is then calculated from the following formula. Solubility (mass%) = polymer mass / (polymer mass + organic solvent mass) x 100

[0084] <Polymer synthesis method> The synthesis of the polymer can be carried out by known polymerization methods such as living radical polymerization, living anionic polymerization, and atom transfer radical polymerization. For example, in the case of living radical polymerization, a copolymer can be obtained by reacting a monomer with a polymerization initiator such as AIBN (α,α'-azobisisobutyronitrile). In the case of living anionic polymerization, a polymer can be obtained by reacting a monomer with butyllithium in the presence of lithium chloride. Note that, although an example of polymer synthesis is shown in this example, the present embodiment is not limited thereto, and the polymer can be appropriately synthesized by each of the above synthesis methods or known synthesis methods. For example, the method described in International Publication WO99 / 062964 can be used.

[0085] In addition, when the polymer contains a unit derived from the structure represented by the above-mentioned general formula (101), the synthesis of the polymer may be performed in combination with a step of extracting from lignocellulose derived from woody plants or herbaceous plants. For example, when a method of extracting from lignocellulose derived from woody plants or herbaceous plants is adopted, the extraction method described in JP 2012-100546 A or the like can be used.

[0086] Xylan can be extracted, for example, by the method disclosed in JP-A-2012-180424. Cellulose can be extracted, for example, by the method disclosed in JP 2014-148629 A.

[0087] When synthesizing a polymer containing a unit derived from the structure represented by general formula (101), it is preferable to use the OH group of the sugar moiety obtained by the above extraction method after modifying it by acetylation, halogenation, etc. For example, when an acetyl group is introduced, an acetylated sugar derivative moiety can be obtained by reacting with acetic anhydride.

[0088] When synthesizing copolymers, Macromolecules Vol.36, No.6, 2003 can be used as a reference. Specifically, each compound is placed in a solvent containing DMF, water, acetonitrile, etc., and a reducing agent is added. Examples of reducing agents include NaCNBH3. The mixture is then stirred at 30°C to 100°C for 1 day to 20 days, and reducing agent is added as necessary. A precipitate is obtained by adding water, and the solids are vacuum dried to obtain the copolymer.

[0089] In addition to the above-mentioned methods, examples of the copolymer synthesis method include synthesis methods using radical polymerization, RAFT polymerization, ATRP polymerization, click reaction, and NMP polymerization. Radical polymerization is a polymerization reaction that occurs by adding an initiator and generating two free radicals through a thermal or photoreaction. By heating a monomer (e.g., a styrene monomer and a sugar methacrylate compound in which methacrylic acid is added to the β-1 position at the terminal of a xylooligosaccharide) and an initiator (e.g., an azo compound such as azobisbutyronitrile (AIBN)) at 150°C, a polystyrene-polysaccharide methacrylate random copolymer can be synthesized. RAFT polymerization is a radical-initiated polymerization reaction that involves an exchange chain reaction using thiocarbonylthio groups. For example, the OH group at the terminal 1 position of xylooligosaccharides can be converted to a thiocarbonylthio group, and then styrene monomer can be reacted at 30°C to 100°C to synthesize a copolymer (Material Matters vol.5, No.1, Latest Polymer Synthesis, Sigma-Aldrich Japan Co., Ltd.). In ATRP polymerization, the terminal OH group of a sugar is halogenated, and then reacted with a metal complex [(CuCl, CuCl2, CuBr, CuBr2, CuI, etc.) + TPMA (tris(2-pyridylmethyl)amine)], MeTREN (tris[2-(dimethylamino)ethyl]amine), etc.), a monomer (e.g., styrene monomer), and a polymerization initiator (2,2,5-trimethyl-3-(1-phenylethoxy)-4-phenyl-3-azahexane) to synthesize a sugar copolymer (e.g., a sugar-styrene block copolymer). In NMP polymerization, an alkoxyamine derivative is used as an initiator and heated to couple with monomer molecules and produce nitroxides. The polymerization reaction then proceeds as radicals are generated by thermal dissociation. This type of NMP polymerization is a type of living radical polymerization reaction. By mixing monomers (for example, styrene monomers and sugar methacrylate compounds in which methacrylic acid is added to the β-1 position at the end of xylooligosaccharides), using 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) as an initiator, and heating at 140°C, a polystyrene-polysaccharide methacrylate random copolymer can be synthesized. The click reaction is a Cu-catalyzed 1,3-dipolar azide / alkyne cycloaddition reaction of propargyl-containing sugars.

[0090] <Organic solvent> The resist material may further contain an organic solvent. However, the resist material may further contain an aqueous solvent such as water or various aqueous solutions in addition to the organic solvent. Examples of the organic solvent include alcohol-based solvents, ether-based solvents, ketone-based solvents, sulfur-containing solvents, amide-based solvents, ester-based solvents, and hydrocarbon-based solvents. These solvents may be used alone or in combination of two or more.

[0091] Examples of alcohol-based solvents include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, tert-butanol, n-pentanol, i-pentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol, sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec- Examples of the alcohol include heptadecyl alcohol, furfuryl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, and diacetone alcohol; ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1H,1H-trifluoroethanol, 1H,1H-pentafluoropropanol, and 6-(perfluoroethyl)hexanol.

[0092] Examples of polyhydric alcohol partial ether solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and dipropylene glycol monopropyl ether.

[0093] Examples of ether solvents include diethyl ether, dipropyl ether, dibutyl ether, diphenyl ether, and tetrahydrofuran (THF).

[0094] Examples of ketone solvents include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-i-butyl ketone, methyl-n-pentyl ketone, methyl-i-pentyl ketone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, di-i-butyl ketone, trimethylnonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, acetophenone, and furfural.

[0095] An example of the sulfur-containing solvent is dimethyl sulfoxide.

[0096] Examples of amide solvents include N,N'-dimethylimidazolidinone, N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropionamide, and N-methylpyrrolidone.

[0097] Examples of ester-based solvents include diethyl carbonate, propylene carbonate, methyl acetate, ethyl acetate, γ-butyrolactone, γ-valerolactone, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, n-nonyl acetate, methyl acetoacetate, ethyl acetoacetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, Examples of the monomer include diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, glycol diacetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, i-amyl propionate, methyl 3-methoxypropionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate, and diethyl phthalate.

[0098] Examples of the hydrocarbon solvent include aliphatic hydrocarbon solvents such as n-pentane, i-pentane, n-hexane, i-hexane, n-heptane, i-heptane, 2,2,4-trimethylpentane, n-octane, i-octane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, i-propylbenzene, diethylbenzene, i-butylbenzene, triethylbenzene, di-i-propylbenzene, n-amylnaphthalene, and anisole.

[0099] Among these, the organic solvent is more preferably propylene glycol monomethyl ether acetate (PGMEA), N,N-dimethylformamide (DMF), propylene glycol monomethyl ether (PGME), anisole, ethanol, methanol, acetone, methyl ethyl ketone, hexane, tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), 1H,1H-trifluoroethanol, 1H,1H-pentafluoropropanol, 6-(perfluoroethyl)hexanol, ethyl acetate, propyl acetate, butyl acetate, cyclohexanone, furfural, N-methylpyrrolidone, or γ-butyrolactone, and even more preferably PGMEA, PGME, THF, butyl acetate, anisole, cyclohexanone, N-methylpyrrolidone, γ-butyrolactone, or DMF, and even more preferably PGMEA, PGME, or anisole. These solvents may be used alone or in combination of two or more.

[0100] The content of the organic solvent is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, based on the total mass of the resist material. The content of the organic solvent is preferably 99.9% by mass or less, and more preferably 99% by mass or less. By setting the content of the organic solvent within the above range, the coatability of the resist material can be improved.

[0101] <Optional ingredients> The resist material may contain optional components as described below.

[0102] <<Monomer components>> The resist material may further contain a monomer component constituting the polymer in addition to the polymer, such as the compound represented by the general formula (101) and the compounds represented by the general formulas (102) and / or (103) described above.

[0103] <<Crosslinkable compound>> The resist material may further contain a crosslinking compound, which strengthens the resist film formed by the crosslinking reaction and enhances the etching resistance.

[0104] The crosslinkable compound is not particularly limited, but a crosslinkable compound having at least two crosslink-forming substituents is preferably used. A compound having at least one type of crosslink-forming substituent selected from an isocyanate group, an epoxy group, a hydroxymethylamino group, and an alkoxymethylamino group, for example, two to six, can be used as the crosslinkable compound. The crosslinkable compound can be a single type of compound, or a combination of two or more types of compounds.

[0105] These crosslinking compounds can undergo a crosslinking reaction by self-condensation, or can undergo a crosslinking reaction with a structural unit contained in a polymer.

[0106] <<Catalyst>> The resist material may contain an acid compound such as p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium-p-toluenesulfonic acid, salicylic acid, sulfosalicylic acid, citric acid, benzoic acid, ammonium dodecylbenzenesulfonate, or hydroxybenzoic acid as a catalyst for promoting the crosslinking reaction. Examples of the acid compound include aromatic sulfonic acid compounds such as p-toluenesulfonic acid, pyridinium-p-toluenesulfonic acid, sulfosalicylic acid, 4-chlorobenzenesulfonic acid, 4-hydroxybenzenesulfonic acid, benzenedisulfonic acid, 1-naphthalenesulfonic acid, or pyridinium-1-naphthalenesulfonic acid. In addition, an acid generator such as 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate, phenyl-bis(trichloromethyl)-s-triazine, benzoin tosylate, or N-hydroxysuccinimide trifluoromethanesulfonate can be added.

[0107] <<Anti-reflection agent>> The resist material may further include an antireflection agent. Examples of the antireflection agent include compounds having light absorption properties. Examples of the compounds having light absorption properties include those having high absorption ability for light in the photosensitive characteristic wavelength region of the photosensitive component in the photoresist provided on the antireflection film, such as benzophenone compounds, benzotriazole compounds, azo compounds, naphthalene compounds, anthracene compounds, anthraquinone compounds, and triazine compounds. Examples of the polymer include polyester, polyimide, polystyrene, novolac resin, polyacetal, and acrylic polymer. Examples of the polymer having a light-absorbing group linked by a chemical bond include polymers having a light-absorbing aromatic ring structure such as an anthracene ring, a naphthalene ring, a benzene ring, a quinoline ring, a quinoxaline ring, and a thiazole ring.

[0108] <<Other Ingredients>> The resist material may further contain an ionic liquid, a surfactant, etc. By including an ionic liquid in the resist material, the compatibility between the polymer and the organic solvent can be increased. The resist material can be made to contain a surfactant to improve the applicability of the resist material to a substrate. Preferred surfactants include nonionic surfactants, fluorine-based surfactants, and silicon-based surfactants. In addition, any other materials such as known rheology modifiers, adhesion promoters, acid generators, sensitizers, and quenchers may be included in the resist material.

[0109] The content of the optional components as described above is preferably 10 mass % or less, and more preferably 5 mass % or less, based on the total mass of the resist material.

[0110] (resist film) A resist film is formed by applying the resist material as described above onto a substrate. The resist film is, for example, a film (protective film) provided on a substrate in order to form a pattern on the substrate, such as a silicon wafer. The resist film may be a film provided so as to be in direct contact with the substrate, or may be a film laminated on the substrate via another layer. The resist film is processed into a pattern shape to be formed on the substrate, and the portion remaining as the pattern shape becomes a protective film in the subsequent etching process. After the pattern is formed on the substrate, the resist film (protective film) may be removed from the substrate. In this way, the resist film is used, for example, in a process of forming a pattern on a substrate. The resist film includes a layered film before the pattern is formed, and an intermittent film after the pattern is formed.

[0111] The thickness of the resist film can be adjusted appropriately depending on the application, but for example, it is preferably 1 nm or more and 20,000 nm or less, more preferably 1 nm or more and 10,000 nm or less, even more preferably 1 nm or more and 5,000 nm or less, and particularly preferably 1 nm or more and 3,000 nm or less.

[0112] The metal content of the resist film after the metal is introduced is preferably 1 at% or more, more preferably 5 at% or more, even more preferably 7 at% or more, and particularly preferably 10 at% or more. The metal content can be calculated, for example, by the following method. The resist film after the metal is introduced is subjected to EDX analysis (energy dispersive X-ray analysis) using an electron microscope JSM7800F (manufactured by JEOL Ltd.), and the ratio of the metal component (metal content) is calculated, which is the metal content. EXAMPLES

[0113] The features of the present invention will be described in more detail below with reference to examples and comparative examples. The materials, amounts used, ratios, processing contents, processing procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below.

[0114] [Synthesis of copolymer 1] (Synthesis of acetyl sugar methacrylate 1-methyl chloroacrylate-α-methylstyrene random copolymer) 12.2g of acetyl sugar methacrylate 1, 4.2g of methyl 2-chloroacrylate (Tokyo Chemical Industry Co., Ltd.), and 3.6g of α-methylstyrene (Tokyo Chemical Industry Co., Ltd.) were mixed with 100g of THF as a solvent and 0.8g of azobisisobutyronitrile as a polymerization initiator in a flask, and then the flask was sealed and replaced with nitrogen. The temperature was raised to 78°C under a nitrogen atmosphere and stirred for 6.0 hours. After that, the temperature was returned to room temperature, the flask was placed under air, and 300g of methanol was dropped into the obtained solution to precipitate a polymer. Then, the solution containing the precipitated polymer was suction filtered to obtain 11g of white copolymer-1. The structures of the respective structural units of the obtained copolymer-1 are as follows. [ka] n=91, m=91, l=78

[0115] [Preparation of resist evaluation samples] The synthesized copolymer 1 was weighed and dissolved in anisole (Tokyo Chemical Industry Co., Ltd.) at 23° C. to give a concentration of 3.0% by mass.

[0116] (Example 1: Te) As a resist solution, ZEP520A (manufactured by Zeon Corporation), whose main component is a copolymer of α-chloromethyl acrylate and methylstyrene, was prepared. The resist solution was applied to a silicon wafer using a spin coater to form a resist film with a thickness of 100 nm. The resist film was then baked at 180°C for 1 minute. The silicon wafer was transported into a chamber having a hot plate heated to 150°C, and the pressure was reduced to 10 Pa. Metal gas (diethyl tellurium, manufactured by abcr Corporation) was introduced into the chamber to 100 Pa, and the chamber was left to stand for 300 seconds to allow the metal gas to penetrate into the resist film. The chamber was then depressurized to 10 Pa to remove the metal gas, and then water vapor was introduced to 200 Pa, and the chamber was left to stand for 300 seconds, after which the chamber was depressurized to 10 Pa to remove the water vapor. The chamber was returned to atmospheric pressure, and the silicon wafer was then removed. Next, using an electron beam lithography system ELS-F125 (manufactured by Elionix) as the exposure unit, the resist film on the silicon wafer was irradiated with an electron beam under conditions of an acceleration voltage of 50 kV and a current of 500 pA (wavelength of 0.0053 nm), and the dose was 60 μC / cm 2 , 160μC / cm 2 , 260μC / cm 2 The repeat pattern of 100 nm grooves and 100 nm spaces with a dose of 60 μC / cm 2 , 160μC / cm 2 , 260μC / cm 2 Ten repeating patterns of 30 nm grooves and 30 nm spaces were created for each setting. After the electron beam irradiation, the resist film was transferred onto a spin coater, rotated at 100 rpm, and developed by pouring 23°C pentyl acetate (Tokyo Chemical Industry Co., Ltd.) over it for 10 seconds. The resist film was then rotated at 2000 rpm to dry it.

[0117] (Example 2: Sn) A pattern was formed on a resist film in the same manner as in Example 1, except that the metal gas in Example 1 was changed from diethyl tellurium to tetramethyltin (manufactured by Merck).

[0118] (Example 3: Te, sugar material) A pattern was formed in a resist film in the same manner as in Example 1, except that a 3% anisole solution of copolymer 1 was used instead of ZEP520A as the resist solution in Example 1.

[0119] Comparative Example 1 A pattern was formed in a resist film in the same manner as in Example 1, except that the metal gas was not injected.

[0120] Comparative Example 2 A pattern was formed in the resist film in the same manner as in Example 1, except that the metal gas was injected after the electron beam irradiation (after the exposure step) rather than after the application of the resist film.

[0121] Comparative Example 3 A pattern was formed in a resist film in the same manner as in Example 1, except that the metal gas was injected after development rather than after application of the resist film.

[0122] (evaluation) Samples for evaluating the resolution, contrast, and aspect ratio were prepared, and the resolution, contrast, and aspect ratio were evaluated as follows. The dose was changed, and the results of the dose that gave the best evaluation results were used as the evaluation results.

[0123] Rating 1 (resolution) The surface and cross section of the 100 nm wide line and space portion were observed using a scanning electron microscope (SEM) JSM7800F (manufactured by JEOL Ltd.) at an acceleration voltage of 5 kV, an emission current of 86.0 μA, and a magnification of 100,000 times to confirm the resolution. The condition was evaluated according to the following evaluation criteria. Note that a state in which there was no residue from the resist film in the space portion was evaluated as high resolution. ◯: A pattern is formed, and no residue from the resist film is found in the spaces. ×: Unable to develop, or even if developed, residue from the resist film is found in the spaces.

[0124] Rating 2 (contrast) The cross section of the resist film before exposure and the 100 nm wide line and space part after development were observed using a scanning electron microscope (SEM) JSM7800F (manufactured by JEOL Ltd.) at an acceleration voltage of 5 kV, an emission current of 86.0 μA, and a magnification of 100,000 times, and the difference in resist pattern height before and after development was measured. A state in which the change in resist height was small was evaluated as having contrast. ○: (height of resist film before development) - (height of resist film after development) is within 10 nm ×: (height of resist film before development) - (height of resist film after development) is 10 nm or more

[0125] Rating 3 (aspect ratio) The surface of the 30 nm wide line and space portion was observed using a scanning electron microscope (SEM) JSM7800F (manufactured by JEOL Ltd.) at an acceleration voltage of 5 kV, an emission current of 86.0 μA, and a magnification of 100,000 times to confirm the state of the pattern where the aspect ratio is theoretically 3.3. The state was evaluated according to the following evaluation criteria. It is known that when the aspect ratio is low, the pattern collapses or becomes non-linear, and conversely, when the aspect ratio is high, the pattern does not collapse and becomes linear. A state where the pattern is linear in the theoretical aspect value was evaluated as having a high aspect ratio. ◯: A pattern is formed and the pattern is linear. ×: Unable to develop, or even if developed, the pattern is not linear but meandering, or has fallen over and stuck to the adjacent pattern.

[0126] Rating 4 (workability) The space portion of a 100 nm-wide line and space portion was etched on the silicon substrate by performing plasma treatment with trifluoromethane gas (100 sccm, 1 Pa, 100 W, 30 seconds) using an ICP plasma etching device (Tokyo Electron Ltd.), and the processability was evaluated. For the pattern forming portion of the silicon substrate after development and etching, a cut surface perpendicular to the extension direction of the line and space was formed, and this cut surface was observed with a scanning electron microscope (SEM) JSM7800F (manufactured by JEOL Ltd.) at an acceleration voltage of 1.5 kV, an emission current of 37.0 μA, and a magnification of 100,000 times to measure the height of the resist and the processing depth of the silicon substrate. Then, the value of the processing depth of the silicon substrate / (height of the resist before processing-height of the resist after processing) was calculated, and when this value was 1.1 or more, it was determined that the processability was good. ○: Processing depth of silicon substrate / (height of resist before processing - height of resist after processing) ≧ 1.1 ×: Processing depth of silicon substrate / (height of resist before processing-height of resist after processing)<1.1

[0127] [Table 1]

[0128] In the examples, the resist film had a high resolution, and a pattern with a high contrast and a high aspect ratio was formed. Also, the processability was good in the examples.

[0129] In addition, in Examples 1 and 3, the thickness of the resist film was changed to 40 nm, the exposure unit was changed to an EUV scanner NXE3300 manufactured by ASML, and a pattern was formed by irradiating the resist film with EUV light having a wavelength of 13.5 nm through a photomask patterned so as to expose a 20 nm line and space pattern. When the line and space portion was observed using a scanning electron microscope (SEM) JSM7800F (manufactured by JEOL Ltd.) at an acceleration voltage of 5 kV, an emission current of 86.0 μA, and a magnification of 100,000 times, in both cases, there was no resist remaining in the space portion, and even after development, the change in resist height was small, and a linear pattern was formed.

[0130] In addition, in Comparative Example 2, no pattern was formed at all, and in Comparative Example 3, the resolution was low, the contrast was low, and the aspect ratio was low. However, when the part where the pattern was formed was selected and the processability was evaluated, the processability tended to be good. From these results, it was found that in order to form a good pattern, it is optimal to perform the metal introduction process before the exposure process. [Explanation of symbols]

[0131] 10 Substrate 40 Resist film

Claims

1. applying a resist material onto a substrate to form a resist film; introducing a metal into the resist film; An exposure process; A developing step, The resist material includes a polymer, and the polymer includes a unit derived from a structure represented by the following general formula (101), a pattern forming method, wherein the polymer is a chain scission type polymer; 【Chemistry 1】 In general formula (101), R １ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted acyl group, an optionally substituted allyl group, an optionally substituted alkoxy group, or an optionally substituted alkylsilyl group, １ may be the same or different; R １１ represents a hydrogen atom or an alkyl group which may have a substituent; R ２ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or a halogenated alkyl group; Y １ represents a single bond or a linking group.

2. The R ２ 2. The pattern forming method according to claim 1, wherein is a fluorine atom, a chlorine atom or a bromine atom.

3. The pattern formation method according to claim 1, wherein the resist material contains a polymer, and the polymer contains a unit derived from at least one selected from structures represented by the following general formulas (102) to (103): 【Chemistry 2】 【Chemistry 3】 In general formula (102), X １ represents an optionally substituted alkyl group, an optionally substituted acyl group, or an optionally substituted allyl group; R ３ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or a halogenated alkyl group; Y ２ represents a single bond or a linking group; In general formula (103), X ２ represents an aryl group which may have a substituent; R ４ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or a halogenated alkyl group; Y ３ represents a single bond or a linking group.

4. 4. The pattern formation method according to claim 3, wherein the polymer contains a unit derived from a structure represented by any one of the general formulae (101) to (103).

5. The R ２ ~R ４ 5. The pattern formation method according to claim 4, wherein at least one of the following is a fluorine atom, a chlorine atom or a bromine atom.

6. The pattern formation method according to any one of claims 1 to 5, wherein the step of introducing a metal is a step of introducing at least one selected from the group consisting of Mg, Al, Ag, Ge, Cd, W, Ta, Hf, Zr, Mo, In, Sn, Sb, and Te.

7. 7. The pattern formation method according to claim 1, wherein the step of introducing a metal uses a metal material in which at least one selected from a halogen, an alkyl group, and an aminoalkyl group is bonded to a metal element.

8. A resist material containing a polymer including a unit derived from a structure represented by the following general formula (101): a resist material in which the polymer is a chain-scission type polymer and is used for introducing a metal; 【Chemistry 4】 In general formula (101), R １ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted acyl group, an optionally substituted allyl group, an optionally substituted alkoxy group, or an optionally substituted alkylsilyl group, １ may be the same or different; R １１ represents a hydrogen atom or an alkyl group which may have a substituent; R ２ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or a halogenated alkyl group; Y １ represents a single bond or a linking group.

9. The resist material according to claim 8, which contains a polymer including a unit derived from at least one selected from the structures represented by the following general formulas (102) to (103), and is used for introducing a metal: 【Chemistry 5】 【Chemistry 6】 In general formula (102), X １ represents an optionally substituted alkyl group, an optionally substituted acyl group, or an optionally substituted allyl group; R ３ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or a halogenated alkyl group; Y ２ represents a single bond or a linking group; In general formula (103), X ２ represents an aryl group which may have a substituent; R ４ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or a halogenated alkyl group; Y ３ represents a single bond or a linking group.

10. The resist material according to claim 9, wherein the polymer contains units derived from structures represented by any one of the general formulas (101) to (103).

11. The R ２ ~R ４ 11. The resist material according to claim 10, wherein at least one of the following is a fluorine atom, a chlorine atom, or a bromine atom.

12. A pattern forming apparatus used in the pattern forming method according to any one of claims 1 to 7, a unit for applying a resist material onto a substrate to form a resist film; a unit for introducing a metal into the resist film; An exposure unit; a development unit.

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