Pattern formation method, resist material, and pattern formation apparatus

Abstract

The present invention addresses the problem of providing a method for forming a fine pattern having high contrast on a resist film. The present invention relates to a pattern formation method including a step in which a resist material is applied on a substrate and a resist film is formed, a step in which a metal is introduced into the resist film, an exposure step, and a development step. The present invention also relates to a resist material and a pattern formation device.

Description

Technical Field

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

Background Art

[0002] Electronic devices such as semiconductors are required to have higher definition due to miniaturization. In addition, diversification of the shape of patterns of semiconductor devices is also being considered. As a method for forming such patterns, 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 electromagnetic waves such as ultraviolet rays are irradiated through a photomask on which a pattern of a semiconductor device is drawn, and the resulting photoresist pattern is used as a protective film to etch the substrate, whereby fine irregularities corresponding to the above pattern can be formed on the substrate.

[0003] For example, Patent Document 1 discloses a method of forming a pattern by spin-coating a solution containing an α-methylstyrene·α-chloroacrylate copolymer on a substrate, performing pre-baking, then performing electron beam exposure, and performing development processing. Patent Document 2 also discloses a method for forming a coating capable of forming a pattern with radiation. Specifically, Patent Document 2 discloses a method for forming a coating including a step of depositing a coating solution containing an organic solvent, a first organometallic composition, and a metal compound having a hydrolyzable ligand-metal bond on a substrate, and further exposing a precursor coating on the substrate to water.

[0004] Patent Document 3 discloses a pattern forming method including a film forming step and a contact step of bringing a pattern forming material film into contact with a metal compound containing a metal element. Here, the film forming step includes a step of forming a film containing a pattern forming material, a step of irradiating an electromagnetic wave on a first region of the film, and a step of removing the first region, and after these steps, a contact step of bringing it into contact with a metal compound containing a metal element is provided.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] As described above, in the lithography method using a photoresist, methods for forming a fine pattern have been studied. However, in the conventional pattern formation method, the contrast of the resist material after pattern formation may be low, and improvement has been demanded.

[0007] Therefore, the present inventors have proceeded with studies for the purpose of providing a method for forming a fine pattern with high contrast on a resist film in order to solve such problems of the prior art.

Means for Solving the Problems

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

[0009] [1] A pattern formation 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. A step of introducing a metal into the resist film, An exposure step, and A development step. [2] The resist material contains a polymer, and the polymer contains units derived from at least one selected from the structures represented by the following general formulas (101) to (103), the pattern forming method according to [1];

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

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

[11] The resist material according to

[10] , wherein at least one of R 2 to R 4 is a fluorine atom, a chlorine atom or a bromine atom.

[12] A pattern forming apparatus comprising 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. [Advantages of the Invention]

[0010] According to the manufacturing method of the present invention, a resist film with high contrast and fine patterns can be formed. [Brief Description of the Drawings]

[0011]

Figure 1

Best Mode for Carrying Out the Invention

[0012] Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on typical embodiments or specific examples, but the present invention is not limited to such embodiments. In this specification, a numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value.

[0013] (Pattern Formation Method) The present invention relates to a pattern formation 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. In the pattern formation method of the present invention, the step of forming a resist film, the step of introducing a metal into the resist film, the exposure step, and the development step are included in this order.

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

[0015] The pattern formation method of the present invention includes a step of introducing metal into a resist film between the step of forming the resist film and the exposure step. By providing a step of introducing metal into the resist film between the step of forming the resist film and the exposure step in this way, a resist film with high contrast can be formed. The contrast of the resist film can be evaluated as high when the difference in the height of the resist pattern before and after development is measured, and the value of the height of the resist film before development - the height of the resist film after development is small. That is, when the change in the resist height before and after development is small, the resist film can be evaluated as having high contrast.

[0016] Also, according to the pattern formation method of the present invention, the resolution of the resist film can be increased. The resolution can be evaluated as good when a resist film is formed and a pattern of 100 nm width line and space is formed, and a desired pattern structure is formed and there is no residue derived from the resist film in the space part.

[0017] Furthermore, according to the pattern formation method of the present invention, a pattern with a high aspect ratio can be formed on the resist film. The aspect ratio of the resist film is a value calculated by the height of the resist film / the width of the resist film in the line part of the line and space formed on the resist film. In this specification, in a state where the theoretical aspect value is obtained, when observing the pattern shape, if the pattern is linear, it can be evaluated that the aspect ratio is high.

[0018] In the pattern formation method of the present invention, the resist material used for forming the resist film does not contain a metal component, and metal is introduced after forming the resist film. Thereby, the stability of the resist material can be further enhanced. Also, in the pattern formation method of the present invention, metal is introduced at a stage before forming a pattern shape on the resist film. Thereby, the contrast of the patterning of the resist film can be more effectively increased.

[0019] <Step of forming a resist film> Examples of substrates used in the pattern formation method include substrates such as glass, silicon, SiN, GaN, and AlN. Further, a substrate made of an organic material such as PET, PE, PEO, PS, cycloolefin polymer, polylactic acid, or cellulose nanofiber may also be used.

[0020] Before applying the resist material to the substrate, it is preferable to provide a step of cleaning the substrate. By cleaning the substrate surface, the coatability of the resist material is improved. As the cleaning treatment method, a conventionally known method can be used, and examples include oxygen plasma treatment, ozone oxidation treatment, acid-base treatment, and chemical modification treatment.

[0021] The method of applying the resist material is not particularly limited. For example, the resist material can be applied onto the substrate by a known method such as the 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 of applying the resist material is preferably the spin method.

[0022] After applying the resist material, the resist material may be cured by heating to form a resist film. In particular, when the resist material is applied by the spin coating method, the solvent in the resist material can be removed in a short time by providing a heating step. The temperature when heating the coating film is not particularly limited, but is preferably 60°C or higher and 550°C or lower. Further, the heat treatment is preferably a heat treatment under the atmosphere and at a relatively low temperature. The method of heating is not particularly limited, and methods such as using a hot plate or irradiating infrared rays can be adopted. Among them, the method using a hot plate is simple and preferable. Also, the atmosphere during heating can be the atmosphere, under an inert gas such as nitrogen, or under 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 such that adjacent layers are in direct contact in this order, but other layers may be provided between the respective layers. 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 is a layer that enhances the adhesion between the substrate and the resist film. Further, an antireflection 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 for example, SiO 2 、SiN,Al 2 O 3 、AlN, GaN, GaAs, W, Cr, Ru, Ta, TaN, SOG, amorphous carbon and other inorganic materials, and organic materials such as commercially available SOC and adhesives can be mentioned.

[0024] <Step of introducing metal> The pattern formation method of the present invention further includes a metal introduction step during the steps of forming a resist film and an exposure step. In this case, examples of the metal introduction step include a step of introducing a metal into the resist film, such as the SIS method (Sequencial 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, Lu, and the like. 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, and more preferably at least one selected from the group consisting of Sn, Sb, and Te. Such a process can be carried out by, for example, the method described in Jornal of Photopolymer Science and Technology Volume 29, Number 5 (2016) 653-657.

[0025] In the step of introducing a metal, it is preferable to adopt a method of introducing by permeating a metal gas into the resist film, a method of introducing by implanting metal ions into the resist film using an ion implantation method, or a method of introducing 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 to the inside of the resist film and the metal and the components in the resist film form a bond by a chemical reaction.

[0026] In the method of infiltrating metal gas into the resist, it is preferable to put the substrate with the resist film formed into a vacuum chamber to create a vacuum condition, and then fill the vacuum chamber with metal gas. In the vacuum chamber, it is preferable to keep the metal gas filled for a certain period of time. After the reaction, return the inside of the vacuum chamber to normal pressure and take out the substrate with the resist film formed. Note that after introducing the metal gas into the resist film, water vapor, ozone, etc. may be brought into contact with the resist film. Also, taking the above process as one cycle, the process of infiltrating the metal gas into the resist may be performed 1 to 100 cycles. Performing the process of infiltrating the metal gas into the resist once is preferable because the process time can be shortened. On the other hand, performing the process of infiltrating the metal gas into the resist multiple times is preferable because more metal can be further introduced into the resist film.

[0027] In the subsequent process of the process of introducing metal, a heating process may be provided. By heating, the penetration of the metal into the resist film can be promoted. The heating method is not particularly limited, and examples include laser irradiation such as a hot plate or infrared rays, and xenon flash lamp irradiation.

[0028] As the metal gas used in the step of introducing a metal, 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 can be used. 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, tetrakis(dimethylamino)hafnium, tetramethoxyhafnium, trimethylaluminum, bis(diisopropylpropionamidinato)-cobalt, diisopropylpropionamidinato-copper, tetrakis(tridimethylamino)titanium, dimethyltellurium, diethyltellurium, di(isopropyl)tellurium, di(isopropyl)ditellurium, tri(isopropyl)antimony, tetramethyltin, tetrakis(dimethylamino)tin, tri(isobutyl)indium, tri(isobutyl)gallium, pentakis(dimethylamino)tantalum, bis(acetylacetonato)magnesium, tetraethoxygermanium, tetraethylgermanium, tetramethoxygermanium, dimethylcadmium, tetraisopropyloxydizirconium, tetrakis(dimethylamido)zirconium, bis(methylcyclopentadienyl)methoxymethyldizirconium, bis(methylcyclopentadienyl)dimethylhafnium, bis(t-butylimino)bis(dimethylamino)molybdenum, bis(t-butylimino)bis(dimethylamino)tungsten, etc. can be mentioned. Among them, a metal gas in which at least one selected from a halogen, an alkyl group, and an aminoalkyl group is bonded to a metal element is preferable because of its high reactivity. These metal gases can be applied by using their vapors even if they are liquid or solid at room temperature. In order to generate vapor, the metal gas material can also be heated.

[0029] Incidentally, the present invention may also relate to a metal gas material used in the step of introducing metal in the pattern formation method, which is a metal gas material containing at least one selected from the group consisting of Mg, Al, Ag, Ge, Cd, W, Ta, Hf, Zr, Mo, In, Sn, Sb, and Te. Such a metal gas material is particularly preferably a material in which at least one selected from the group consisting of halogen, alkyl group, and aminoalkyl group is bonded to a metal element.

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

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

[0032] <Exposure step> The exposure process is a process of irradiating an electromagnetic wave onto the resist film after metal introduction to form an arbitrary pattern. The electromagnetic wave is not particularly limited, and for example, a semiconductor laser, a high-pressure mercury lamp such as g-line or i-line, an excimer laser such as ArF or KrF, an electron beam, extreme ultraviolet light, X-rays, etc. can be used. In particular, when using an electron beam or extreme ultraviolet light, the decrease in the resist film thickness can be reduced by using the method of the present invention. Furthermore, an effect that the inspection of the fine pattern structure becomes easier due to the effect of introducing the metal can also be obtained. After exposure, post exposure bake can be performed if necessary. The post exposure bake is preferably performed under the 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 process, the exposure may be performed through a photomask on which an arbitrary pattern is formed, or may be directly drawn 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 portion irradiated with light can be altered to transfer the pattern of the mask. At this time, it is preferable that the main chain of the polymer contained in the resist film is cut in the portion irradiated with light. In the exposed portion, the main chain of the polymer is cut, and in the subsequent development process, the cut polymer is dissolved in the developer, and the resist film (resist material) in the exposed portion is removed. In this way, an intermittent portion is formed in the resist film in the exposed portion, and the substrate 10 is exposed at the intermittent portion of the resist film.

[0034] In addition, when irradiating the resist film with an electromagnetic wave in the exposure process, the wavelength of the electromagnetic wave is not particularly limited, but it is preferably 15 nm or less.

[0035] <Development Process> The development process is a process of forming a pattern by bringing the resist film into contact with a developer after exposure. The development method is not particularly limited, and a dip method, a spin coating method, or the like can be employed. Also, the development temperature may be room temperature and can be appropriately changed. The developer used in the development process is not particularly limited, and known developers can be used. For example, aromatic compounds 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 γ-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 alkaline aqueous solutions such as aqueous amine solutions of ethanolamine, propylamine, and ethylenediamine can be cited as examples. Also, in the development process, these developers can be mixed and used. Furthermore, a surfactant or the like 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] Also, a rinsing process using a rinsing solution may be provided after the development process. The rinsing solution is not particularly limited, and known rinsing solutions can be used. For example, xylene, butyl acetate, ethanol, isopropyl alcohol, methyl isobutyl ketone, pure water, etc. can be used. As the rinsing solution, these can be used alone or in combination of two or more. Also, a surfactant or the like can be added to these rinsing solutions and used. The conditions of the rinsing process are appropriately selected from a temperature of -70 to 50°C and a time of 10 to 100 seconds.

[0037] <Other Processes> The pattern formation method of the present invention is a method of forming a pattern on a resist film formed from a resist material, and 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 a 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, and physical etching such as ion beam etching. Processing of the semiconductor substrate is preferably performed by dry etching using gases such as tetrafluoromethane, perfluorocyclobutane (C 4 F 8 ), perfluoropropane (C 3 F 8 ), trifluoromethane, carbon monoxide, argon, oxygen, nitrogen, chlorine, sulfur hexafluoride, difluoromethane, nitrogen trifluoride, and chlorine trifluoride.

[0039] (Pattern Forming Apparatus) 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 single-functional units are combined. For example, an apparatus in which a unit for forming a resist film and a unit for introducing a metal into the resist film are integrated into one unit may be used, or an apparatus in which a step of introducing a metal and an exposure step are integrated into one unit may be used. The pattern forming apparatus is preferably an apparatus in which these units are connected by a conveyance means so that a series of steps can be performed.

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

[0041] The unit for forming a resist film may further include heating means. Examples of the heating means include a hot plate, a laser irradiation device such as infrared rays, etc. When the unit for forming a resist film includes heating means, for example, it can be configured to be located adjacent to the supply means. Also, a space where the substrate can be retracted may be provided between the supply means and the heating means, and the processing may be performed by transporting the substrate.

[0042] The unit for introducing metal into the resist film includes a chamber and 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 it is particularly preferable to be equipped with a vacuum pump. After installing the resist film in such a chamber, by supplying metal gas into the chamber and filling it with the metal gas, the resist film can be brought into contact with the metal gas, and thereby, metal can be introduced 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 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 metal while changing the temperature.

[0044] For the unit that introduces metal into the resist film, for example, a spin coater can be used. The atmosphere of the unit that introduces metal into the resist film may be under the atmosphere, or under an inert gas atmosphere such as nitrogen or under vacuum. Particularly under an inert gas atmosphere, it is possible and preferable to use a highly reactive metal solution.

[0045] The exposure unit includes an electromagnetic wave irradiation part. Examples of the electromagnetic wave irradiation part include electromagnetic wave irradiation devices such as 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, and X-rays. Examples of the exposure unit include a unit including an optical part, an electromagnetic wave irradiation part, and a power supply part. In the exposure process, when using a photomask, the exposure unit may be provided with a part for installing the photomask. When taking an exposure method using a photomask, for example, a process called step exposure may be adopted. In step exposure, a substrate having a resist film is transported into the chamber, and electromagnetic waves are irradiated from above through a photomask with a desired pattern processed thereon, and a certain area is exposed under conditions optimized for the irradiation amount, time, focus, etc. This can be repeated multiple times to expose the entire wafer surface. In addition, in an exposure method without using a photomask, for example, after adjusting the focus, dose amount, etc. so that the resist film surface is irradiated with electromagnetic waves, exposure is performed at an arbitrary position to form a desired pattern. Also, when exposing, a method called immersion exposure can be adopted. Immersion exposure is a method of forming a finer pattern by placing water, oil, etc. on the resist film and irradiating electromagnetic waves through this.

[0046] The developing unit preferably includes a developing solution storage tank, a spin coater, and a developing solution supply pipe. In the developing unit, a method can be adopted in which the developing solution is applied from the developing solution 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 developing solution. Further, the developing unit can also include a rinse solution storage tank and a rinse solution pipe. A method can also be adopted in which the rinse solution is applied onto the resist film after the developing solution is removed, and the substrate having the resist film is rotated by the spin coater to remove the rinse solution.

[0047] (Resist material) The resist material used in the pattern forming method of the present invention preferably contains a polymer. Among them, the polymer is preferably a main-chain cleavage type positive resist material (polymer). The polymer contained in the resist material is such that the main chain is cleaved by irradiation with an electron beam, and only the exposed portion is dissolved in the developing solution. Thereby, it becomes possible to form a higher definition pattern.

[0048] In the pattern forming method of the present invention, a metal is introduced into the resist film formed from the resist material. Thus, the resist material is preferably a resist material for metal introduction.

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

Chemical formula

Chemical formula

Chemical formula

[0050] In general formula (101), R 1 each independently represents a hydrogen atom, an alkyl group which may have a substituent, an acyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, or an alkylsilyl group which may have a substituent, and a plurality of R 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, and Y 1 represents a single bond or a linking group. In general formula (102), X 1 represents an alkyl group which may have a substituent, an acyl group which may have a substituent or an aryl group which may have a substituent. R 3 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or a halogenated alkyl group, and 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, and Y 3 represents a single bond or a linking group.

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

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

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

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

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

[0056] In general formula (101), R 11 represents a hydrogen atom or an alkyl group which may have a substituent. R 11 When it represents an alkyl group which may have a substituent, examples of the alkyl group include methyl group, ethyl group, propyl group, etc. Among them, R 11The alkyl group is preferably a methyl group, and such an alkyl group preferably further has a substituent. Examples of the substituent of the alkyl group include a hydroxyl group, an acyl group, an allyl group, an alkoxy group, etc. Among them, the substituent is preferably a hydroxyl group or an acyl group. More specifically, R 11 When representing an alkyl group which may have a substituent, R 11 is preferably -CH 2 OR 1 , and examples of R 1 include the groups described above. However, in the general formula (101), R 11 is particularly preferably a hydrogen atom. By making R 11 a hydrogen atom, it becomes easier to form a finer pattern structure.

[0057] In the 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. Among them, R 2 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. By introducing a fluorine atom, a chlorine atom or a bromine atom into R 2 , the formed resist film can have a higher contrast.

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

Chemical formula

[0059] In the above structural formula, the ※ mark represents the bonding site with the main chain side, and the * mark represents 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-chain structure (chain structure) called an aldose or a ketose.

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

[0062] In general formula (102), X 1 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, and is preferably an alkyl group which may have a substituent. The number of carbon atoms of the alkyl group is preferably 1 or more and 8 or less, more preferably 1 or more and 5 or less, and still more preferably 1 or more and 3 or less. The number of carbon atoms is the number of carbon atoms excluding the substituent. Examples of the alkyl group having a substituent include, for example, -CH 2 -OH, -CH 2 -O-methyl, -CH 2 -O-ethyl, -CH 2 -O-n-propyl, -CH 2 -O-isopropyl, -CH 2 -O-n-butyl, -CH 2 -O-isobutyl, -CH 2 -O-t-butyl, -CH 2 -O-(C=O)-methyl, -CH 2 -O-(C=O)-ethyl, -CH 2 -O-(C=O)-propyl, -CH 2 -O-(C=O)-isopropyl, -CH 2 -O-(C=O)-n-butyl, -CH 2 -O-(C=O)-isobutyl, -CH2 -O-(C=O)-t-butyl, -C 2 H 4 -OH, -C 2 H 4 -O-methyl, -C 2 H 4 -O-ethyl, -C 2 H 4 -O-n-propyl, -C 2 H 4 -O-isopropyl, -C 2 H 4 -O-n-butyl, -C 2 H 4 -O-isobutyl, -C 2 H 4 -O-t-butyl, -C 2 H 4 -O-(C=O)-methyl, -C 2 H 4 -O-(C=O)-ethyl, -C 2 H 4 -O-(C=O)-n-propyl, -C 2 H 4 -O-(C=O)-isopropyl, -C 2 H 4 -O-(C=O)-n-butyl, -C 2 H 4 -O-(C=O)-isobutyl, -C 2 H 4 -O-(C=O)-t-butyl, -C 2 H 4 -O-(C=O)-CH 2 -(C=O)-methyl etc. can be mentioned. Further, 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. Among them, R 3 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. R 3By introducing a fluorine atom, a chlorine atom, or a bromine atom, the formed resist film can have a higher contrast. In addition, when the polymer contained in the resist material contains a unit derived from the structure represented by the above general formula (101) and further contains a unit derived from the structure represented by the above general formula (102), R in the general formula (101) 2 and R in the general formula (102) 3 are preferably at least one of a fluorine atom, a chlorine atom, or a bromine atom. Note that both R in the general formula (101) 2 and R in the general formula (102) 3 may be a fluorine atom, a chlorine atom, or a bromine atom.

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

Chemical formula

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

[0066] The polymer contained in the resist material preferably contains a unit derived from the structure represented by the above general formula (103), and in addition to the unit derived from the structure represented by the above general formula (101), it is preferably further contains a unit derived from the structure represented by the above general formula (103). Among them, it is particularly preferable that the polymer contains all the units derived from the structures represented by the above general formulas (101) to (103).

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

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

[0069] In the 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. Among them, R 4 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. By introducing a fluorine atom, a chlorine atom or a bromine atom into R 4 , the formed resist film can have a higher contrast.

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

[0071] In the general formula (103), Y 3 represents a single bond or a linking group. When Y 2 is a linking group, examples of Y 3 include a group containing an alkylene group, a phenylene group, -O-, -C(=O)O-, etc. Y 3 may be a linking group combining these groups. However, Y 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, p-n-octylstyrene, p-n-decylstyrene, p-n-dodecylstyrene, chlorostyrene, bromostyrene, trimethylsilylstyrene, hydroxystyrene, 3,4,5-methoxystyrene, pentamethyldisilylstyrene, t-butoxycarbonylstyrene, tetrahydropyranylstyrene, phenoxyethylstyrene, t-butoxycarbonylmethylstyrene, and the like.

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

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

[0075] When the polymer contains units derived from the structure represented by the general formula (102), the content ratio (mass %) of the units derived from the structure represented by the 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 with respect to the total mass of the polymer. The content ratio (mass %) of the units derived from the structure represented by the general formula (102) can be calculated in the same manner as the calculation of the content ratio of the units derived from the structure represented by the general formula (101) described above.

[0076] When the polymer contains units derived from the structure represented by the general formula (103), the content ratio (mass %) of the units derived from the structure represented by the 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 with respect to the total mass of the polymer. The content ratio (mass %) of the units derived from the structure represented by the general formula (103) can be calculated in the same manner as the calculation of the content ratio of the units derived from the structure represented by the general formula (101) described above.

[0077] The polymer contained in the resist material preferably contains units derived from the structure represented by the general formula (101) described above, and further preferably contains units derived from the structure represented by the general formula (102) and / or (103). When the polymer contains units 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. Further, the copolymer may have a structure in which a part is a random copolymer and a part is a block copolymer. Thus, an appropriate structure can be selected as appropriate according to the use and required physical properties.

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

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

[0080] The weight average molecular weight (Mw) of the polymer is preferably 500 or more, more preferably 1000 or more, still more preferably 1500 or more. Also, the weight average molecular weight (Mw) of the polymer is preferably 2,000,000 or less, more preferably 1,500,000 or less, still more preferably 1,000,000 or less, and even more preferably 700,000 or less. The weight average molecular weight (Mw) of the polymer is a value measured by polystyrene conversion 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 1 or more. Also, Mw / Mn is preferably 100 or less, more preferably 50 or less, still more preferably 20 or less, even more preferably 15 or less, and particularly preferably 10 or less.

[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 above organic solvent is not particularly limited, but can be, for example, 40% by mass. The above solubility is the solubility in at least any one selected from PGMEA, PGME, THF, butyl acetate, anisole, cyclohexanone, ethyl lactate, N-methylpyrrolidone, γ-butyrolactone and DMF.

[0083] The method for measuring the solubility of the polymer is to gradually add PGMEA, PGME, THF, butyl acetate, anisole, cyclohexanone, ethyl lactate, N-methylpyrrolidone, γ-butyrolactone or DMF to a predetermined amount of the polymer while stirring, and record the amount of the organic solvent added when it is dissolved. For stirring, a magnetic stirrer or the like may be used. Then, the solubility is calculated from the following formula. Solubility (% by mass) = mass of polymer / (mass of polymer + mass of organic solvent) × 100

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

[0085] In addition, when the polymer contains units derived from the structure represented by the general formula (101) described above, the process of extracting from lignocellulose derived from woody plants or herbaceous plants may be combined when synthesizing the polymer. For example, when adopting a method of extracting from lignocellulose derived from woody plants or herbaceous plants, the extraction methods described in JP-A-2012-100546 and the like can be used.

[0086] Regarding xylan, for example, it can be extracted by the method disclosed in JP-A-2012-180424. Regarding cellulose, for example, it can be extracted by the method disclosed in JP-A-2014-148629.

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

[0088] When synthesizing a copolymer, synthesis can also be carried out with reference to Macromolecules Vol.36, No.6, 2003. Specifically, each compound is put into a solvent containing DMF, water, acetonitrile, etc., and a reducing agent is added. Examples of the reducing agent include NaCNBH 3 and the like. Then, it is stirred at 30°C or higher and 100°C or lower for 1 day or more and 20 days or less, and the reducing agent is appropriately added as necessary. By adding water, a precipitate is obtained, and the copolymer can be obtained by vacuum drying the solid content.

[0089] As methods for synthesizing the copolymer, in addition to the above method, methods using radical polymerization, RAFT polymerization, ATRP polymerization, click reaction, and NMP polymerization can be mentioned. Radical polymerization is a polymerization reaction that occurs by adding an initiator to generate two free radicals through a thermal reaction or a photoreaction. A polystyrene-polysaccharide methacrylate random copolymer can be synthesized by heating a monomer (for example, a sugar methacrylate compound in which methacrylic acid is added to the β-1 position at the end of a xylooligosaccharide and a styrene monomer) and an initiator (for example, an azo compound such as azobisisobutyronitrile (AIBN)) at 150°C. RAFT polymerization is a radical-initiated polymerization reaction involving an exchange chain reaction using a thiocarbonylthio group. For example, a method can be adopted in which the OH group attached to the terminal 1-position of xylooligosaccharide is converted into a thiocarbonylthio group, and then a styrene monomer is reacted at 30°C or higher and 100°C or lower to synthesize a copolymer (Material Matters vol.5, No.1 Latest Polymer Synthesis, Sigma-Aldrich Japan Co., Ltd.). ATRP polymerization involves halogenating the terminal OH group of a sugar and reacting it with a metal complex [(CuCl, CuCl 2 , CuBr, CuBr 2 or CuI, etc.) + TPMA (tris(2-pyridylmethyl)amine), MeTREN (tris[2-(dimethylamino)ethyl]amine), etc.), a monomer (for example, a styrene monomer), and a polymerization initiator (2,2,5-trimethyl-3-(1-phenylethoxy)-4-phenyl-3-azahexane) to synthesize a sugar copolymer (for example, a sugar-styrene block copolymer). NMP polymerization involves heating with an alkoxyamine derivative as an initiator to cause coupling and reaction with monomer molecules, generating nitroxide. Subsequently, radicals are generated by thermal dissociation, and the polymerization reaction proceeds. Such NMP polymerization is a type of living radical polymerization reaction. A monomer (for example, a sugar methacrylate compound in which methacrylic acid is added to the β-1 position at the end of a xylooligosaccharide and a styrene monomer) is mixed, and 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) is used as an initiator, and heating at 140 °C enables the synthesis of a polystyrene-polysugar methacrylate random copolymer. The click reaction is a 1,3-dipolar azide / alkyne cycloaddition reaction using a sugar having a propargyl group and a Cu catalyst.

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

[0091] Examples of the alcohol 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-heptadecyl alcohol, furfuryl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, diacetone alcohol, etc.; 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, 6-(perfluoroethyl)hexanol, etc.

[0092] In addition, 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, dipropylene glycol monopropyl ether, and the like.

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

[0094] Examples of ketone solvents include, for example, 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, furfural, and the like.

[0095] Examples of sulfur-containing solvents include, for example, dimethyl sulfoxide and the like.

[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, N-methylpyrrolidone, and the like.

[0097] Examples of ester 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, 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, diglycol diacetate, methoxytriethylene glycol 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, diethyl phthalate, and the like.

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

[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, still 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 still more preferably 30% by mass or more with respect to the total mass of the resist material. Also, 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] <Any component> The resist material may contain optional components as described below.

[0102] <<Monomer component>> In addition to the polymer, the resist material may further contain a monomer component that constitutes the polymer. Examples of the monomer component include the compounds represented by the general formula (101), the general formula (102), and / or (103) described above.

[0103] <<Crosslinkable compound>> The resist material may further contain a crosslinkable compound. By this crosslinking reaction, the formed resist film becomes strong and the etching resistance can be enhanced.

[0104] The crosslinkable compound is not particularly limited, but a crosslinkable compound having at least two crosslink-forming substituents is preferably used. As the crosslinkable compound, a compound having two or more, for example, 2 to 6 crosslink-forming substituents selected from an isocyanate group, an epoxy group, a hydroxymethylamino group, and an alkoxymethylamino group can be used. Only one kind of compound can be used, or two or more kinds of compounds can be used in combination.

[0105] These crosslinkable compounds can cause a crosslinking reaction by self-condensation. They can also cause a crosslinking reaction with the constitutional units contained in the polymer.

[0106] <<Catalyst>> As a catalyst for promoting the crosslinking reaction in the resist material, acid compounds such as p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium-p-toluenesulfonic acid, salicylic acid, sulfosalicylic acid, citric acid, benzoic acid, ammonium dodecylbenzenesulfonate, hydroxybenzoic acid, etc. can be added. Examples of acid compounds 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, pyridinium-1-naphthalenesulfonic acid, etc. Also, acid generators 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, N-hydroxysuccinimide trifluoromethanesulfonate, etc. can be added.

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

[0108] <<Other components>> The resist material may further contain an ionic liquid, a surfactant, etc. By incorporating an ionic liquid into the resist material, the compatibility between the polymer and the organic solvent can be enhanced. By incorporating a surfactant into the resist material, the coatability of the resist material onto the substrate can be improved. Preferred surfactants include nonionic surfactants, fluorosurfactants, and silicone surfactants. In addition, known rheology modifiers, adhesion aids, acid generators, sensitizers, quenching agents, and any other materials may be included in the resist material.

[0109] Note that the content of any of the above-described optional components is preferably 10% by mass or less, and more preferably 5% by mass or less, based on the total mass of the resist material.

[0110] (Resist film) A resist film is formed by coating the above-described resist material onto a substrate. The resist film is, for example, a film (protective film) provided on the substrate in order to form a pattern on a substrate such as a silicon wafer. The resist film may be a film provided so as to directly contact the substrate, or may be a film laminated on the substrate via another layer. The resist film is processed into the pattern shape to be formed on the substrate, and the portion left as the pattern shape becomes the protective film in the subsequent etching process. Note that after the pattern is formed on the substrate, the resist film (protective film) may be removed from the substrate. Thus, the resist film is used, for example, in the process of forming a pattern on a substrate. Note that the resist film includes both a layered film before pattern formation and an intermittent film after pattern formation.

[0111] The film thickness of the resist film can be appropriately adjusted according to the application, but is preferably 1 nm or more and 20000 nm or less, more preferably 1 nm or more and 10000 nm or less, still more preferably 1 nm or more and 5000 nm or less, and particularly preferably 1 nm or more and 3000 nm or less.

[0112] After the introduction of the metal, the metal content rate of the resist film is preferably 1 at% or more, more preferably 5 at% or more, still more preferably 7 at% or more, and particularly preferably 10 at% or more. The metal content rate can be calculated, for example, by the following method. For the resist film after metal introduction, EDX analysis (energy dispersive X-ray analysis) is performed using an electron microscope JSM7800F (manufactured by JEOL Ltd.), the ratio of the metal component (metal content rate) is calculated, and this is taken as the metal content rate.

Examples

[0113] The features of the present invention will be described more specifically below by way of examples and comparative examples. The materials, amounts used, ratios, treatment details, treatment 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 construed as being limited by the specific examples shown below.

[0114] [Synthesis of Copolymer 1] (Synthesis of Acetyl Sugar Methacrylate - Methyl 2-Chloroacrylate - α-Methylstyrene Random Copolymer) To 12.2 g of acetyl sugar methacrylate, 4.2 g of methyl 2-chloroacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), and 3.6 g of α-methylstyrene (manufactured by Tokyo Chemical Industry Co., Ltd.), 100 g of THF as a solvent and 0.8 g of azobisisobutyronitrile as a polymerization initiator were mixed in a flask, and then the flask was sealed and purged with nitrogen. Under a nitrogen atmosphere, the temperature was raised to 78°C and stirred for 6.0 hours. Then, the temperature was returned to room temperature, the inside of the flask was brought to the atmosphere, and 300 g of methanol was added dropwise to the obtained solution to precipitate a polymer. Then, the solution containing the precipitated polymer was suction filtered to obtain 11 g of white copolymer-1. The structures of the respective structural units of the obtained copolymer-1 are as follows.

Chemical formula

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

[0116] (Example 1: Te) As a resist solution, ZEP520A (manufactured by Nippon Zeon Co., Ltd.), which is a copolymer of α-chloromethyl acrylate and methylstyrene as the main component, was prepared. The resist solution was applied onto a silicon wafer using a spin coater to form a resist film with a thickness of 100 nm. Subsequently, the resist film was baked at 180 °C for 1 minute. The silicon wafer was transferred into a chamber equipped with a hot plate heated to 150 °C, and the pressure was reduced to 10 Pa. Metal gas (diethyl tellurium, manufactured by abcr) was introduced into this chamber to a pressure of 100 Pa, and left standing for 300 seconds to allow the metal gas to penetrate into the resist film. Subsequently, the pressure inside the chamber was reduced to 10 Pa to remove the metal gas. Then, water vapor was introduced to a pressure of 200 Pa, left standing for 300 seconds, and then the pressure inside the chamber was reduced to 10 Pa to remove the water vapor. After returning the pressure inside the chamber to atmospheric pressure, the silicon wafer was taken out. Next, using an electron beam lithography apparatus ELS-F125 (manufactured by Elionix) as an exposure unit, an electron beam was irradiated onto the resist film on the silicon wafer under the conditions of an acceleration voltage of 50 kV and a current of 500 pA (wavelength 0.0053 nm), and the dose amounts were set to 60 μC / cm 2 , 160 μC / cm 2 , 260 μC / cm 2 respectively, and 10 repeating patterns of 100 nm grooves and 100 nm spaces, and dose amounts of 60 μC / cm 2 , 160 μC / cm 2 , 260 μC / cm 2 respectively, and 10 repeating patterns of 30 nm grooves and 30 nm spaces were each fabricated 10 times. The resist film after electron beam irradiation was transferred onto a spin coater, rotated at a speed of 100 rpm, and pentyl acetate (manufactured by Tokyo Chemical Industry) at 23 °C was flowed over for 10 seconds for development. Thereafter, the resist film was rotated at a speed of 2000 rpm to be dried.

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

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

[0119] (Comparative Example 1) In Example 1, a pattern was formed on the resist film in the same manner as in Example 1, except that no metal gas was injected.

[0120] (Comparative Example 2) In Example 1, a pattern was formed on the resist film in the same manner as in Example 1, except that the metal gas was injected after electron beam irradiation (after the exposure process) instead of after resist film coating.

[0121] (Comparative Example 3) In Example 1, a pattern was formed on the resist film in the same manner as in Example 1, except that the metal gas was injected after development instead of after resist film coating.

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

[0123] Evaluation 1 (Resolution) Regarding the surface and cross-section of a 100 nm-width line-and-space portion, observation was performed using a scanning electron microscope (SEM) JSM7800F (manufactured by JEOL) 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 state was evaluated according to the following evaluation criteria. A state without residue derived from the resist film in the space portion was evaluated as having high resolution. 〇: A pattern is formed and no residue derived from the resist film is observed in the space part. ×: It cannot be developed, or even if it can be developed, residues derived from the resist film are observed in the space part.

[0124] Evaluation 2 (contrast) The cross-section of the resist film before exposure and the 100-nm-wide line-and-space part after development 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, and the difference in the resist pattern height before and after development was measured. A state with a small change in resist height was evaluated as having contrast. 〇: (Height of the resist film before development) - (Height of the resist film after development) is within 10 nm ×: (Height of the resist film before development) - (Height of the resist film after development) is 10 nm or more

[0125] Evaluation 3 (aspect ratio) The surface of the 30-nm-wide line-and-space part 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, and the state of the pattern at the point where the aspect ratio theoretically becomes 3.3 was confirmed. The state was evaluated according to the following evaluation criteria. It is known that when the aspect ratio is low, the pattern collapses or the pattern becomes non-linear, and conversely, when the aspect ratio is high, the pattern becomes linear without collapsing. A state where the pattern is linear at the theoretical aspect ratio value was evaluated as having a high aspect ratio. 〇: A pattern is formed and the pattern is linear. ×: It cannot be developed, or even if it can be developed, the pattern is not linear but meandering, or it has collapsed and adhered to an adjacent pattern.

[0126] Evaluation 4 (processability) Etching was performed on a silicon substrate by subjecting the space portion of a 100-nm-wide line-and-space portion to plasma treatment (100 sccm, 1 Pa, 100 W, for 30 seconds) with trifluoromethane gas using an ICP plasma etching apparatus (manufactured by Tokyo Electron Limited), and the processability was evaluated. For the pattern-formed portions of the developed and etched silicon substrates, a cross-section perpendicular to the extending direction of the line and space was formed, and this cross-section 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, and the height of the resist and the etching depth of the silicon substrate were measured. Then, the value of the etching 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. 〇: Etching depth of silicon substrate / (height of resist before processing - height of resist after processing) ≧ 1.1 ×: Etching depth of silicon substrate / (height of resist before processing - height of resist after processing) < 1.1

[0127]

Table 1

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

[0129] In Example 1 and Example 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 EUV light with a wavelength of 13.5 nm was irradiated onto the resist film through a photomask patterned so as to be able to expose a 20-nm line-and-space pattern to form a 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, there was no remaining resist in the space portion in both cases, and even after development, the change in resist height was small, and a linear pattern was formed.

[0130] In Comparative Example 2, no pattern was formed at all. In Comparative Example 3, the resolution was low, the contrast was low, and the aspect ratio was low. However, when the processability evaluation was performed by selecting the portion where the pattern was formed, a good tendency in processability was observed. 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 Reference Numerals

[0131] 10 Substrate 40 Resist film

Claims

1. 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; A development step, which are included in this order, The step of introducing the metal is a step of permeating a metal gas into the resist film, The resist material contains a polymer, and the polymer contains units derived from structures represented by the following general formulas (101) to (103), A pattern forming method in which at least any one of R2 to R4 in the following general formulas (101) to (103) is a fluorine atom, a chlorine atom, or a bromine atom; 【Chemical 1】 【Chemical 2】 [Chemical 3] In general formula (101), each R1 independently represents a hydrogen atom, an alkyl group which may have a substituent, an acyl group which may have a substituent, an allyl group which may have a substituent, an alkoxy group which may have a substituent, or an alkylsilyl group which may have a substituent, and a plurality of R1s may be the same or different; R11 represents a hydrogen atom or an alkyl group which may have a substituent; R2 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom, or a halogenated alkyl group, and Y1 represents a single bond or a linking group; In general formula (102), X1 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; R3 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom, or a halogenated alkyl group, and Y2 represents a single bond or a linking group; In general formula (103), X2 represents an aryl group which may have a substituent; R4 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom, or a halogenated alkyl group, and Y3 represents a single bond or a linking group.

2. The step of introducing the 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. The pattern forming method according to Claim 1.

3. In the step of introducing the metal, a metal material to which at least one selected from a halogen, an alkyl group, and an aminoalkyl group is bonded to a metal element is used. The pattern forming method according to Claim 1 or 2.

4. A resist material used in the pattern forming method according to any one of Claims 1 to 3, A resist material containing a polymer including units derived from structures represented by the following general formulas (101) to (103), wherein at least any one of R2 to R4 in the following general formulas (101) to (103) is a fluorine atom, a chlorine atom, or a bromine atom, and which is a resist material for metal introduction; 【Chemical 4】 [Chemical Formula 5] 【Chemical Formula 6】 In the general formula (101), R １ each independently represents a hydrogen atom, an alkyl group which may have a substituent, an acyl group which may have a substituent, an allyl group which may have a substituent, an alkoxy group which may have a substituent, or an alkylsilyl group which may have a substituent, and a plurality of R 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, and Y １ represents a single bond or a linking group; In the general formula (102), X １ represents an alkyl group which may have a substituent, an acyl group which may have a substituent, or an aryl group which may have a substituent; R ３ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom, or a halogenated alkyl group, and Y ２ represents a single bond or a linking group; In the 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, and Y ３ represents a single bond or a linking group.

5. A pattern forming apparatus used in the pattern forming method according to any one of Claims 1 to 3, 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, and including the pattern forming apparatus.

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