Liquid state composition and combustion method for liquid state composition

Abstract

[Problem] To provide a composition which can be used for a developing solution in lithography, a fuel for combustion, or the like. [Solution] The present invention comprises a liquid and a metal, wherein the liquid includes at least one substance selected from the group consisting of fatty acids, furan derivatives, and turpentine derivatives, and the metal content is not more than 10 ppb.

Description

Liquid-state composition and method for burning the liquid-state composition

[0001] Some aspects of the present invention relate to a composition that is in a liquid state under predetermined conditions, such as room temperature and atmospheric pressure, and is used as a chemical solution such as a developer used in a lithography process or as a fuel for combustion. The present invention also relates to a method for manufacturing a device using the composition and a method for burning the composition.

[0002] Currently, cutting-edge semiconductor devices are being fabricated with patterns having half pitches of 20 nm or less, and various fine patterning processes are being utilized, such as double patterning (SADP, SAQP, or SAOP), extreme ultraviolet (EUV) exposure, electron beam lithography, and nanoimprinting.

[0003] In double patterning, the NTD (negative tone development) method is used to prevent roughness on the sidewalls of the resist pattern, and organic solvents (butyl acetate, amyl acetate, hexyl acetate, heptyl acetate, octyl acetate, nonyl acetate, anisole, methyl isobutyl ketone, etc.) are used as developers.

[0004] In EUV exposure, new resist materials are being used to improve the absorption efficiency of resist materials for EUV. Examples of such new resist materials include metal oxide resists (MORs) and main chain scission resist polymers, which are developed using organic solvents (butyl acetate, amyl acetate, hexyl acetate, heptyl acetate, octyl acetate, nonyl acetate, anisole, methyl isobutyl ketone, etc.).

[0005] In electron beam lithography, new resist materials are being used to improve the efficiency of electron beam absorption. These new resist materials are basically the same as those used for EUV exposure, and the developer used in this process is also the same as that used for EUV exposure.

[0006] In nanoimprinting, a process similar to development is carried out, in which an organic solvent (butyl acetate, amyl acetate, hexyl acetate, heptyl acetate, octyl acetate, nonyl acetate, anisole, methyl isobutyl ketone, etc.) is applied to facilitate peeling of the remaining film and the adhesive film underneath the remaining film after resist pattern transfer, thereby reducing sidewall roughness.

[0007] The above-mentioned developers are organic materials (liquids) derived from fossil resources, as described in Patent Document 1. Furthermore, aiming for carbon neutrality, straight vegetable oil (SVO) fuel is increasingly being added to fossil fuels and used in automobiles and jet aircraft.

[0008]

[0009] Patent Publication No. 2018-22141

[0010] The above-mentioned developer is an organic material (liquid) derived from fossil resources, and its production emits carbon dioxide from energy sources. Furthermore, the developer is not recovered and reused after the development process, but is instead discarded as industrial waste and burned, emitting carbon dioxide. Furthermore, developers are not reused because it can lead to defective semiconductor devices and increase refining costs, and so developers manufactured using fossil resources are discarded after a single use.

[0011] Furthermore, developers play an important role in forming fine patterns, affecting resolution, roughness, defect generation, and dimensional variation. However, there are only a limited number of developers that are superior to conventional petroleum-derived developers in forming fine patterns.

[0012] A composition according to some embodiments of the present invention comprises a liquid and a metal, wherein the liquid contains one or more substances selected from the group consisting of fatty acids, furan derivatives, and turpentine derivatives, and the metal content is 10 ppb or less. A composition according to some embodiments of the present invention comprises a liquid and a plurality of microparticles, wherein the liquid contains one or more substances selected from the group consisting of fatty acids, furan derivatives, and turpentine derivatives, and each of the plurality of microparticles has a diameter of 0.15 microns or more and less than 0.2 microns.

[0013] In the above composition, the number of the plurality of fine particles is 100 particles / cm ３ Preferably, the viscosity of the composition is 8 mPa·s or less. In the composition, the viscosity of the composition is 8 mPa·s or less. In the composition, the furan derivative is preferably at least one of furfural, furfuryl alcohol, and tetrahydrofurfuryl alcohol. In the composition, the turpentine derivative is preferably at least one of dihydrotapinyl acetate and tapinyl methyl ether.

[0014] In the above-mentioned composition, at least one of the fatty acid, the furan derivative, and the turpentine derivative is preferably obtained from a biological source. In the above-mentioned composition, the composition is preferably used as a developer for pattern formation in the manufacture of semiconductor devices. In the above-mentioned composition, it is preferably in a liquid state at room temperature and atmospheric pressure.

[0015] A method for producing a composition according to some embodiments of the present invention includes a filtration step of filtering a material to be purified using a filter to obtain the composition. In the method for producing a composition described above, the filtration step is preferably a multistage filtration step in which the material to be purified is passed through two or more filters that differ in at least one property selected from the group consisting of filter material, pore size, and impurities to be removed.

[0016] A device manufacturing method according to some embodiments of the present invention includes a composition preparation step of preparing the above-described composition, and a lithography step of performing photolithography, electron beam lithography, or nanoimprint lithography, in which the composition is used as a developer. In the device manufacturing method described above, the photolithography is preferably double patterning photolithography or EUV photolithography.

[0017] The method for manufacturing a device described above preferably further comprises a recovery step of recovering the composition used in the lithography step after the lithography step is performed. A method for burning a composition according to some embodiments of the present invention comprises a step of using the composition recovered by the recovery step in the method for manufacturing a device described above as fuel.

[0018] Some aspects of the present invention can provide a new liquid composition. This liquid composition is derived from biological materials rather than fossil resources and can be used for the same purposes as conventional developers. For example, raw materials for the liquid composition can be extracted from the plant, and the extracted raw materials can be filtered, metals removed, particulates removed, and the like to obtain a liquid composition. When the liquid composition is used as a developer for semiconductor devices, it is called a biomass developer. In particular, plants contribute to carbon neutrality because they absorb carbon dioxide during their growth process.

[0019] Examples of biomass developers include fatty acids that are components of vegetable oil extracted from plants, furan derivatives obtained by chemically reacting sugars or vegetable oil extracted from plants, and turpentine (terpene) derivatives. These are preferably liquid at room temperature and atmospheric pressure, have low viscosity, dissolve exposed portions of the resist, and are less likely to dissolve unexposed portions of the resist. Furthermore, it is preferable that the roughness (edge ​​roughness) of the sidewalls of the fine pattern of the resist after development using the developer is small, and it is also preferable that there are few small defects (defects) where the fine pattern is not locally formed.

[0020] The biomass developer preferably contains, for example, a plant-derived fatty acid containing linoleic acid, oleic acid, and palmitic acid, or a plant-derived furan derivative or turpentine derivative, and has a viscosity of 8 mPa·s or less at room temperature, a particle count of 100 or less particles with a diameter of 0.15 microns or more and less than -0.2 microns, and a metal content of 10 ppb or less.

[0021] Furthermore, a method for burning a liquid composition according to this embodiment includes the steps of preparing a liquid composition at room temperature and atmospheric pressure, the liquid composition containing either a plant-derived fatty acid containing linoleic acid, oleic acid, and palmitic acid, or a plant-derived furan derivative or turpentine derivative, the liquid composition having a viscosity of 8 mPa·s or less at room temperature, a number of particles in the liquid having a diameter of 0.15 microns or more but less than -0.2 microns of 100 or less, and a metal content of 10 ppb or less in the developer. The combustion method further includes the steps of using the liquid composition as a developer for double patterning, extreme ultraviolet (EUV) exposure, electron beam lithography, or nanoimprinting, and using the liquid composition recovered after use as the developer as fuel. When recovered after development, this liquid composition contains 1% or less of components derived from fossil resources, making it a biomass component usable as fuel.

[0022] The liquid composition according to some embodiments of the present invention has a relatively low viscosity and a low impurity concentration, making it suitable for use as a developer in lithography processes. When the liquid composition is used as a developer, the developer has low viscosity and dissolves the exposed portion of the resist but is less likely to dissolve the unexposed portion. Furthermore, after development using the developer, the sidewall roughness (edge ​​roughness) of the fine resist pattern is minimal, and there are fewer microscopic defects (faults) where the fine pattern is not locally formed. Furthermore, the carbon dioxide emissions from the production and disposal of this biomass developer are 0.2 to 0.5 kg per 1 kg of developer, which is significantly lower than those of conventional developers derived from fossil resources.

[0023] Furthermore, the composition recovered after development is in a liquid state that can be reused as biomass fuel for biomass power generation, biomass fuel for heat sources such as boilers, biojet fuel, etc., and will significantly contribute to reducing carbon dioxide emissions.

[0024] <<General Processes Used in Semiconductor Devices>> <Double Patterning> In double patterning, a resist pattern with a relatively large pitch size of at least twice the pitch is first formed. Next, dry etching is performed to narrow the width of the resist convexities by about half. Next, a vacuum film formation method such as ALD (atomic layer deposition) is performed on the sidewalls of the narrowed resist convexities, and a film of an inorganic compound such as SiO2 is formed until the width of the resist convexities returns to their original size. Next, only the resist is selectively removed by dry etching. This forms a concave-convex pattern made of an inorganic compound with a pitch half the original pitch size.

[0025] This process is performed once or repeatedly to form a fine pattern. The resist is exposed to ultraviolet light, such as that having a wavelength of 193 nm, baked, and then developed with the biomass developer of this embodiment to form a relief pattern. A typical example of a resist is a chemically amplified resist. A chemically amplified resist is a mixture of a resin, a photoacid generator (PAG), and a quencher. For example, a resist containing the following structural formula (resin: 83 wt %, PAG: 16.5 wt %), 0.5 wt % quencher, and PGMEA (propylene glycol monomethyl ether acetate) as a solvent can be used. The biomass developer of this embodiment can be used for development using the NTD method (negative tone development method).

[0026] resin PAG quencher

[0027] <EUV exposure and electron beam lithography> In EUV exposure, a resist pattern is formed by exposure using an EUV scanner (such as the NXE series manufactured by ASML with a wavelength of 13.5 nm and an NA of 0.33, or the EXE series manufactured by ASML with a wavelength of 13.5 nm and an NA of 0.55, or the HYPER series manufactured by ASML with a wavelength of 13.5 nm and an NA of 0.75). Here, a resist that can be developed with the biomass developer of this embodiment after electron beam lithography to form a pattern is used. A resist that can be patterned by electron beam lithography is developed after EUV exposure to form a relief pattern. Typical resists used include metal oxide resists (MOR) and main chain scission resists.

[0028] The MOR may be an organotin oxide hydroxide or an organometallic complex containing the following chemical formulas 4 and 5. The MOR is dissolved in a solvent such as anisole at a concentration of about 2% by weight, applied to a wafer, and baked. After exposure and baking, the wafer is developed with the biomass developer of this embodiment to form a pattern.

[0029] 4 5

[0030] The main chain scission resist is made of a methyl chloroacrylate / methylstyrene copolymer or the like. Approximately 2% by weight of the resist is dissolved in a solvent such as anisole, applied to the wafer, and baked. After exposure, the resist is baked and developed with the biomass developer of this embodiment to form a pattern.

[0031] In electron beam lithography, a metal oxide resist (MOR) or a main chain scission resist used in EUV exposure is used. It has been reported that there is a correlation between the results of resist pattern formation in both electron beam lithography and EUV exposure, and resists that produce good results in electron beam lithography also produce good results in EUV exposure.

[0032] <Nanoimprinting> In nanoimprinting, a master plate on which a fine pattern called a template is formed is first created, and a pattern is formed by transferring a resist pattern, which is an ultraviolet-curable resin, from the master plate. The fine pattern of the template is formed by electron beam lithography on resist applied to a template substrate, followed by development with the biomass developer of this embodiment to form the fine pattern. The resist used in this process is the same as that used in electron beam lithography. Next, the template and wafer are introduced into a nanoimprinting device (manufactured by Canon) and nanoimprinting is performed.

[0033] After applying resist (UV-curable resin) to the wafer using inkjet printing or other methods, the resist is pressed against the template surface, then irradiated with UV light to harden the resist. The template is then peeled off, transferring a fine pattern onto the wafer. Next, to reduce the thickness of the resist recesses (RLT), known as the residual resist film, and reduce the edge roughness of the pattern, the resist is developed with the biomass developer of this embodiment, followed by dry etching to remove the residual film. The resist (UV-curable resin) used here is a radical-curable type, such as a solventless UV-curable resist consisting of 20% by weight of pulverized orange acrylate, 25% isobornyl acrylate, 50% trimethylpropane triacrylate, and 5% polymerization initiator (Irgacure 184).

[0034] <<Biomass Developer: Composition in a Liquid State at Room Temperature and Atmospheric Pressure>> A composition in a liquid state at room temperature and atmospheric pressure, which is used in the above-mentioned double patterning, EUV (extreme ultraviolet) exposure, electron beam lithography, or nanoimprinting, will be described. Hereinafter, vegetable oil extracted from plants and the like were used as a material for the biomass developer (hereinafter also referred to as the developer) of this embodiment.

[0035] Various fatty acids, furan derivatives, and turpentine derivatives can be obtained by chemically reacting the fatty acids contained in these vegetable oils, the sugars extracted from the plants, or the vegetable oils. Specifically, the various fatty acids, furan derivatives, and turpentine derivatives were obtained by the following process.

[0036] 100% vegetable oils were used for various fatty acids: rice oil, corn oil, soybean oil, rapeseed oil, palm oil, castor oil, and sunflower oil. The various fatty acids (rice oil (fatty acid K), corn oil (fatty acid C), soybean oil (fatty acid S), rapeseed oil (fatty acid A), palm oil (fatty acid Y), castor oil (fatty acid HM), and sunflower oil (fatty acid H)) were obtained by filtering the crude vegetable oil liquid extracted from plant raw materials in an extractor.

[0037] The furan derivatives used were furfural, furfuryl alcohol, and tetrahydrofurfuryl alcohol. Furfural was obtained by treating D-xylose (manufactured by Okamura Oil Mills) extracted from corn cobs with sulfuric acid and then hydrolyzing it (top of Chemical Formula 6). Furfuryl alcohol was obtained by hydrogenating furfural with water, carbon dioxide, and a highly active supported palladium catalyst (middle of Chemical Formula 6). Tetrahydrofurfuryl alcohol was obtained by hydrogenating furfuryl alcohol with water, carbon dioxide, and a highly active supported palladium catalyst (bottom of Chemical Formula 6).

[0038] 6

[0039] The turpentine derivatives used were dihydroterpinyl acetate, isobornyl acetate, dihydroterpinyloxyethanol, and terpinyl methyl ether. Dihydroterpinyl acetate was produced by reacting turpentine oil (pinene 75%, carene) extracted from pine resin with water, bioacetic acid chloride, and scandium triflate. Terpineol was then produced by hydrogenation and esterification with bioacetic acid chloride to produce dihydroterpinyl acetate. Terpineol was produced by reacting turpentine oil (pinene 75%, carene) extracted from pine resin with water, bioacetic acid chloride, and scandium triflate to produce dihydroterpinyl acetate. Terpineol was then methylated with sulfuric acid and biomethanol to produce terpinyl methyl ether. Commercially available isobornyl acetate and dihydroterpinyloxyethanol (derivatives of turpentine oil) were used.

[0040] <Filtering> The composition, which is in a liquid state at room temperature and atmospheric pressure, is filtered when used with a biomass developer. For filtering of the developer, conditions A, B, C, D, E, F, G, H, I, J, and K were set based on the number of filtering times using a particulate removal filter (filter sizes 25 nm, 10 nm, and 5 nm), a metal removal filter, and a particulate removal filter (filter size 1 nm). Details of these conditions are as follows.

[0041] Condition A: (same below), once through a 25 nm filter, once through a 10 nm filter, once through a 5 nm filter, twice through a metal removal filter, and twice through a 1 nm filter. Condition B: once through a 25 nm filter, once through a 10 nm filter, twice through a metal removal filter, and twice through a 1 nm filter. Condition C: once through a 25 nm filter, once through a 10 nm filter, once through a 5 nm filter, once through a metal removal filter, and twice through a 1 nm filter. Condition D: once through a 25 nm filter, once through a 10 nm filter, once through a metal removal filter, and twice through a 1 nm filter. Condition E: once through a 10 nm filter, once through a metal removal filter, and twice through a 1 nm filter. Condition F: once through a 25 nm filter, once through a 10 nm filter, once through a 5 nm filter, once through a metal removal filter, and once through a 1 nm filter. Condition G: once through a 25 nm filter, once through a 10 nm filter, once through a metal removal filter, and once through a 1 nm filter. Condition H: 1x 25nm filter, 1x metal removal filter, 1x 1nm filter. Condition I: 1x 25nm filter, 1x 10nm filter, 1x 5nm filter, 1x metal removal filter, 1x 5nm filter. Condition J: 1x 25nm filter, 1x 10nm filter, 1x metal removal filter, 1x 5nm filter. Condition K: 1x 25nm filter, 1x metal removal filter, 1x 5nm filter.

[0042] <Evaluation Results of Biomass Developer> The developer was evaluated based on the viscosity at room temperature, the number of particles in the developer with a diameter of 0.15 microns or more and less than -0.2 microns, and the metal content in the developer. The metal elements used to measure the metal content were Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ru, Pd, Ag, Cd, In, Sn, Ba, Hf, Ta, W, Os, Ir, Pt, Au, and Pb, and the value of the element with the highest content among them was measured.

[0043] The evaluation results of the developer shown in Table 1 were obtained under the filtering condition A. Condition A is the strictest filtering among the above conditions.

[0044] <Pattern Evaluation Results> Table 1 also shows the results of patterns recorded on resist by electron beam lithography and developed with various developers. The pattern results were evaluated based on the minimum half pitch (hp) of the formed pattern, the amount of development in the unexposed area, LWR (line edge roughness), CDU (line width variation), and the number of minute defects where no line or space was formed.

[0045] The resist used was a methyl chloroacrylate / methylstyrene / imide compound copolymer (Mw = 200,000), which was dissolved in PGMEA solvent to a concentration of 2 wt %. This resist was applied to a silicon wafer to a thickness of 40 nm, baked, and then patterned using an electron beam lithography system. The resist was then developed using the biomass developer of this embodiment.

[0046] For advanced semiconductor devices, the minimum HP is preferably 20 nm or less, the developed amount of the unexposed area is preferably 1 nm or less, the LWR is preferably 1 nm or less, the CDU is preferably 1.5 nm or less, and the number of defects is preferably 1 μm or less. ２ Preferably, there are 10 or fewer.

[0047] In Table 1, fatty acids, furan derivatives, or turpentine derivatives that were good in all of the minimum half pitch, the amount of development in the unexposed area, LWR (line edge roughness), CDU (variation in line width), and the number of micro-defects where no line / space was formed were marked with a double circle in the judgment column, and those that were not good in any of the evaluation results were marked with an x ​​in the judgment column.

[0048] Table 1

[0049] Table 2 shows the proportions of linoleic acid, erucic acid, oleic acid, palmitic acid, linolenic acid, and stearic acid in fatty acid K, fatty acid C, fatty acid S, fatty acid A, fatty acid Y, fatty acid HM, and fatty acid H.

[0050] Comparing the good fatty acids (fatty acid K, fatty acid C, fatty acid S, fatty acid A) with the bad fatty acids (fatty acid Y, fatty acid HM, fatty acid H), it can be seen that the good fatty acids contain linoleic acid, oleic acid, and palmitic acid, while the bad fatty acids do not contain linoleic acid, oleic acid, or palmitic acid.

[0051] Furthermore, furfural, furfuryl alcohol, and tetrahydrofurfuryl alcohol are good furan derivatives, and dihydroterpinyl acetate and terpinyl methyl ether are good turpentine derivatives.

[0052] <Relationship between Biomass Developer Evaluation Results and Pattern Evaluation Results> To evaluate whether there is a relationship between the developer evaluation results and the pattern evaluation results, the filtering conditions were changed. For this purpose, fatty acid K, fatty acid C, furfural, tetrahydrofurfuryl alcohol, terpinyl methyl ether, and dihydroterpinyl acetate, which showed good pattern evaluation results in Table 1, were selected. Then, the filtering conditions were changed to worsen the viscosity of the developer at room temperature, the number of fine particles in the developer with a diameter of 0.15 microns or more and less than -0.2 microns, and the metal content in the developer, and to evaluate whether these items affected the pattern evaluation results. The results are shown in Tables 3 and 4 below.

[0053] Table 3

[0054] Table 4

[0055] These results show that even if the fatty acids (fatty acids containing linoleic acid, oleic acid, and palmitic acid), furan derivatives (furfural, furfuryl alcohol, tetrahydrofurfuryl alcohol), and turpentine derivatives (dihydrotapinyl acetate, terpinyl methyl ether) that gave good results in Table 1 are used, the pattern evaluation results will not be good unless the developer satisfies at least one of the following conditions: viscosity of 8 mPa·s or less, the number of fine particles in the developer having a diameter of 0.15 microns or more and less than -0.2 microns is 100 or less, and the metal content in the developer is 10 ppb or less.

[0056] That is, in this embodiment, it is understood that a biomass developer containing either a fatty acid containing linoleic acid, oleic acid, and palmitic acid, a furan derivative, or a turpentine derivative is preferable. Furthermore, it is understood that the biomass developer preferably has a viscosity of 8 mPa·s or less at room temperature, a particle count of 100 or less particles with a diameter of 0.15 microns or more and less than -0.2 microns, and a metal content of 10 ppb or less.

[0057] <<Biomass Fuel>> The biomass developer recovered after development can be used as fuel. The biomass fuel recovered after development is also a liquid composition at room temperature and atmospheric pressure. The biomass developer of this embodiment was recovered after development. The recovered biomass developer was used as fuel for a diesel engine-powered AC 100V generator (6 kva, 50 Hz, manufactured by Sue-Awerken). As a result, AC 100V could be generated without any problems. It was found that the developer of this embodiment can be used as a biomass fuel equivalent to SVO fuel for biomass power generation even after use.

[0058] A good fine pattern can be formed using a plant-derived developer. It is possible to significantly reduce carbon dioxide emissions, and this developer can be recovered after use and reused as biomass fuel for biomass power generation, biomass fuel for a heat source such as a boiler, biojet fuel, etc. In other words, the biomass fuel of this embodiment significantly contributes to reducing carbon dioxide emissions even after being used as a developer.

Claims

1. A composition comprising a liquid and a metal, wherein the liquid contains one or more substances selected from the group consisting of fatty acids, furan derivatives, and turpentine derivatives, and the metal content is 10 ppb or less.

2. A composition comprising a liquid and a plurality of microparticles, wherein the liquid contains one or more substances selected from the group consisting of fatty acids, furan derivatives, and turpentine derivatives, and each of the plurality of microparticles has a diameter of 0.15 microns or more and less than 0.2 microns.

3. The number of the plurality of fine particles is 100 particles / cm ３ 3. The composition of claim 2, wherein:

4. The composition according to claim 1 or 2, wherein the viscosity of the composition is 8 mPa·s or less.

5. The composition according to claim 1 or 2, wherein the furan derivative is at least one of furfural, furfuryl alcohol, and tetrahydrofurfuryl alcohol.

6. The composition according to claim 1 or 2, wherein the turpentine derivative is at least one of dihydrotamarind acetate and tamarind methyl ether.

7. The composition according to claim 1 or 2, wherein at least one of the fatty acid, the furan derivative, and the turpentine derivative is obtained from a biological source.

8. The liquid composition according to claim 1 or 2, which is used as a developer during pattern formation in the manufacture of semiconductor devices.

9. The composition according to claim 1 or 2, wherein the liquid is in a liquid state at room temperature and atmospheric pressure.

10. A method for producing the composition according to claim 1 or 2, comprising a filtration step of filtering the material to be purified using a filter to obtain the composition.

11. The method for producing a composition according to claim 10, wherein the filtration step is a multistage filtration step in which the material to be purified is passed through two or more types of filters that differ in at least one property selected from the group consisting of filter material, pore size, and impurities to be removed.

12. A method for manufacturing a device, comprising: a composition preparation step of preparing the composition according to claim 1 or 2; and a lithography step of performing photolithography, electron beam lithography or nanoimprint lithography, wherein the composition is used as a developer in the lithography step.

13. The method for manufacturing a device according to claim 12, wherein the photolithography is double patterning photolithography or EUV photolithography.

14. The method for manufacturing a device according to claim 12, further comprising a recovery step of recovering the composition used in the lithography step after the lithography step has been carried out.

15. A method for burning a composition, comprising the step of using the composition recovered in the recovery step in the method for manufacturing a device according to claim 14 as fuel.

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