JP2004303870A - Method for forming fine pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a fine pattern being regularly arrayed to a high degree and having a high aspect ratio on the surface of a workpiece. <P>SOLUTION: The method for forming the fine pattern has a process in which a multilayer particle film (12) is formed by coating the upper section of the workpiece (11) with core shell particles (13), in which shell layers (13b) are coated with core particles (13a), in two layers or more; a process in which an etching mask pattern (14) containing the core particles supported by a material for the shell layers is formed by a dry etching to the multilayer particle film; and a process in which the fine pattern (15) is formed to the workpiece by transferring the shape of the etching mask pattern on the workpiece. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pattern forming method, and more particularly to a fine pattern forming method for processing an object to be processed into a pattern having a periodic array structure.
[0002]
[Prior art]
The dramatic improvement in functions of information devices such as personal computers in recent years is largely due to advances in microfabrication technology used for manufacturing semiconductor devices. Heretofore, miniaturization of processing dimensions has been advanced by shortening the wavelength of an exposure light source used for lithography. However, as processing dimensions become finer and patterns become denser, the cost of lithography in the manufacturing process becomes enormous. In a next-generation semiconductor device or a high-density recording medium that has been subjected to fine processing such as patterned media, it is required to reduce the size of the pattern to 50 nm or less. An electron beam or the like is considered to be used as an exposure light source for achieving this, but a very large problem remains in terms of processing throughput.
[0003]
Under such circumstances, attention has been paid to a method utilizing a phenomenon in which a material forms a specific regular array pattern in a self-organizing manner as a processing method that can realize a lower cost and a higher throughput. For example, there is a method of forming a pattern on a substrate to be processed using a template obtained by two-dimensionally assembling fine particles on the substrate to be processed (see Non-Patent Documents 1 and 2). Fine particles can be produced by chemical synthesis, and particles of uniform size can be obtained by centrifugation or the like. Further, by using core-shell fine particles in which the periphery of the fine particles is coated with an arbitrary material, the interaction between the fine particles can be adjusted. In this case, it is possible to stably disperse the fine particles in various solvents and develop the self-assembled film on the substrate.
[0004]
In addition, attempts have been made to utilize self-organized regular pattern formation in the phase separation structure of the block copolymer. When such a method is adopted, it is possible to dissolve the block copolymer in an appropriate solvent and apply it on the substrate to be processed, so that a regularly arranged single layer pattern can be formed very easily. For this reason, application as a fine processing method has also been reported (for example, see Non-Patent Documents 3 and 4). In these methods, first, a polymer layer containing a predetermined block copolymer is formed on a substrate to be processed, and then the block copolymer is phase-separated. Further, one polymer phase in the phase separation structure is removed by ozone treatment, plasma etching, electron beam irradiation, or the like to form an uneven pattern. Processing of the substrate to be processed is performed using the uneven pattern as a mask.
[0005]
However, even with such a method using a self-assembled film, it is difficult to form a regular array with a large area when forming an ultrafine pattern having a size of 50 nm or less. If a self-assembled film is formed on the substrate surface as a single layer, the contribution of the interaction at the substrate surface or the air interface increases as the size decreases, making it difficult to form a desired high-quality regular array structure. is there. In a self-assembled film such as metal fine particles, the dispersion of the fine particle intervals becomes large, and the region where no regular arrangement is shown increases. Even with a self-assembled film having a phase separation structure of a block copolymer, the dot spacing variation and the arrangement of dots do not show regularity, and in the worst case, the phase separation structure itself is not formed. As described above, it is difficult to further miniaturize the method using self-organization.
[0006]
In order to avoid this, it is conceivable to use a material in which the fine particles themselves form a two-dimensional array of a single layer. For example, a method that utilizes a self-assembled structure of a two-dimensional crystalline protein molecule forming a membrane structure or the like in a living body has been proposed. However, it is difficult to impart sufficient etching resistance to a protein molecule in an actual etching process, and it is difficult to realize processing with a particularly high aspect ratio even by using a protein molecule.
[0007]
[Non-patent document 1]
H. W. Deckman et al .; Appl. Phys. Lett. Vol. 41, p. 377 (1982)
[0008]
[Non-patent document 2]
P. A. Lewis et al .; Vac. Sci. Technol. Bvol. 11, p. 2938 (1998)
[0009]
[Non-Patent Document 3]
P. Mansky et al .; Appl. Phys. Lett. , Vol. 68, p. 2586
[0010]
[Non-patent document 4]
M. Park et al .; Science, vol. 276, p. 1401
[0011]
[Problems to be solved by the invention]
The present invention provides a method for forming a fine pattern having a high aspect ratio, which is highly regularly arranged, on a surface of a workpiece in a fine processing technique using an etching mask formed by self-assembly of fine particles. The purpose is to:
[0012]
[Means for Solving the Problems]
The pattern forming method according to one embodiment of the present invention includes a step of forming a multilayer fine particle film by densely filling two or more layers of core-shell fine particles in which core fine particles are coated on a shell layer on a workpiece;
Performing dry etching on the multilayer fine particle film to form an etching mask pattern including core fine particles supported by the material of the shell layer; and
A step of transferring a shape of the etching mask pattern to the workpiece to form a fine pattern on the workpiece.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
FIG. 1 is a process sectional view illustrating a method for forming a fine pattern according to an embodiment of the present invention.
[0015]
First, as shown in FIG. 1A, a multilayer film 12 of core-shell fine particles 13 is deposited on a workpiece 11. As the workpiece 11, for example, a workpiece made of a metal, a semiconductor, an insulator, or a dielectric can be used. A metal, semiconductor, insulator, or dielectric thin film formed on a substrate made of glass, Si, or the like may be used as the workpiece 11. The core-shell fine particles 13 have a structure in which the core fine particles 13 are coated with a shell layer 13b.
[0016]
As the core fine particles 13, for example, metal fine particles, dielectric fine particles, polymer fine particles, and the like are used, such as metals, semiconductors, insulators, and polymers. When metal fine particles are used as the core fine particles 13a, for example, j. Cell Biol. vol. 38, page 87 (1985). In the case where fine particles made of a semiconductor or an insulator are used as the core fine particles 13a, for example, J. Am. Am. Chem. Soc. vol. 115, page 8706 (1993). When the diameter of the core fine particles 13a is 50 nm or less, a fine pattern having a large area can be formed at a lower cost than that produced by ultra-high resolution lithography such as an electron beam or an X-ray. Therefore, the diameter of the core fine particles 13a is preferably 50 nm or less.
[0017]
As the shell layer 13b, for example, a metal, a semiconductor, an insulator, a polymer, or the like is used. When a metal, a semiconductor, or an insulator is used as the shell layer 13b, the core-shell fine particles 13 can be manufactured by synthesizing the core fine particles 13a and subsequently forming the shell layer 13b. When a polymer material such as a polymer is used for the shell layer 13b, a polymer material in which a reactive group with the core fine particles 13a is partially introduced is preferable. By using such a polymer material, the adhesion between the core fine particles 13a and the shell layer 13b can be increased.
[0018]
For example, when the core fine particles 13a are noble metal fine particles such as Au, Ag, and Pt, a strong bond state can be formed between the thiol group and the noble metal fine particles by introducing a thiol group as a reactive group. it can. In addition, in the case of other metal fine particles, dielectric fine particles, and polymer fine particles, a reactive group that forms a covalent bond by a chemical reaction, such as methoxysilane, ethoxysilane, and trichlorosilane, a carboxyl group, an alcohol group, and an amino group By introducing a polar group which forms an ionic bond or a covalent bond such as an amide group, a stronger bonding state can be obtained.
[0019]
The materials of the core fine particles 13a and the shell layer 13b can be combined as described above, but in order to form a fine pattern with a high aspect ratio, the etching rate ratio between the core fine particles 13a and the shell layer 13b is sufficiently high. It must be large. To achieve this, it is preferable to use a polymer material for the shell layer 13b. In order to coat the core fine particles 13a with the shell layer 13b made of a polymer material, a predetermined polymer material is added to a colloid solution in which the core fine particles 13a are dispersed, and the adsorption reaction is allowed to proceed for a while. Thereafter, by separating only the core-shell fine particles 13 by centrifugation or the like, the core-shell fine particles 13 obtained by coating the core fine particles 13a with the shell layer 13b made of a polymer material are obtained.
[0020]
In the pattern forming method according to the embodiment of the present invention, since the core-shell fine particles are multilayered into two or more layers, the core-shell fine particles are self-organized not only two-dimensionally but also three-dimensionally with respect to the substrate surface to form a multilayer fine particle film. Is formed. Therefore, the multilayer fine particle film can withstand the interaction at the substrate surface or the air interface, and can form the original highly ordered structure. By performing dry etching on such a multilayer fine particle film, an etching mask pattern including core fine particles supported by the material constituting the shell layer is formed.
[0021]
In order to form an etching mask pattern having a high aspect ratio, the core fine particles 13a must endure dry etching while the shell layer is being etched by dry etching. For this purpose, an etching rate e for the dry etching process of the shell layer 13b is required. _s And the etching rate e of the core fine particles 13a _c It is preferable that a relationship represented by the following mathematical expression (2) is established between.
[0022]
e _s ≧ (√2 + √3) e _c (2)
This is calculated from a geometric calculation in a state in which a two-layer fine particle multilayer film is formed in a close-packed structure. At this time, the thickness t of the shell layer 13b _s And the radius r of the core fine particles 13a _c When the relationship represented by the following equation (1) is established, the core fine particles 13a are etched during the time for etching the shell layer 13b having a thickness from the uppermost surface of the fine particle multilayer film to the surface of the workpiece. Calculated on the condition that they do not disappear due to
[0023]
t _s > ($ 3-1) r _c (1)
This condition can be satisfied by selecting the materials of the core fine particles 13a and the shell layer 13b according to the etching gas used in the dry etching.
[0024]
For example, when using oxygen plasma, it is preferable that the core fine particles 13a be made of a metal or an inorganic dielectric, and the shell layer 13b be made of an organic material such as a polymer. In this case, ideally, the etching rate of the core fine particles 13a can be considered to be almost zero. Therefore, by selectively removing the shell layer 13b, an etching mask pattern having a very large aspect ratio is formed. It becomes possible. Examples of the polymer material that can be used as the shell layer 13b include polystyrene, polymethyl methacrylate, polyethylene, polybutadiene, polycarbonate, polyvinyl chloride, polyimide, and a novolak resin.
[0025]
Also, CF ₄ And CHF ₃ In the case of plasma etching using a fluorine-based gas such as, for example, the core fine particles 13a are made of metal fine particles or a polymer, and the shell layer 13b is made of SiO 2. ₂ Alternatively, it is preferable to use core-shell fine particles 13 composed of a Si-containing polymer. As a result, the shell layer 13b is selectively removed, and an etching mask pattern having a very large aspect ratio is formed.
[0026]
In the embodiment of the present invention, the shape of a two-dimensional etching mask pattern obtained by dry-etching the multilayer fine particle film 12 is transferred onto the workpiece 11. Therefore, when the core-shell fine particles 13 of each layer forming a multilayer overlap on a two-dimensional plane, a mesh-like pattern in which the core fine particles are connected is formed instead of an isolated dot pattern. In high-density recording media and electronic devices, it is required to form an isolated nanometer-sized pattern, and the thickness t of the shell layer 13b of the core-shell fine particles 13 is required. _s Is the radius r of the core fine particles 13a. _c This is made possible by making it larger than (√3-1) times of This relationship is derived from geometric calculations.
[0027]
When the shell layer 13b is made of a metal, a semiconductor, an insulator, or the like and is formed by the above-described method, a desired reaction time of the formation of the shell layer 13b or a type of a solvent at the time of the reaction is adjusted. The thickness of the shell layer 13b can be obtained. When a polymer is used for the shell layer 13b, the shell layer thickness can be controlled by the length of the polymer chain.
[0028]
The multilayer film 12 of the core-shell fine particles 13 in which the core fine particles 13a are made of any one of metal fine particles, dielectric fine particles, and polymer fine particles and the shell layer 13b is made of any one of metal, dielectric, and polymer is prepared as follows. can do. For example, a film of the core-shell fine particles 13 can be formed by dropping a dispersion obtained by dispersing the core-shell fine particles 13 in a solvent on a substrate to be processed and drying the dispersion. By appropriately selecting the concentration of the core-shell fine particles 13 and the type of the solvent in the dispersion, the number of layers of the core-shell fine particles to be formed can be arbitrarily changed. The concentration of the core-shell fine particles 13 can be appropriately selected, for example, within a range of 0.1 mg / ml to 100 mg / ml. As the solvent, for example, ethanol, methanol, propanol, ethyl lactate, ethyl acetate, xylene, tetrahydrofuran, toluene, propylene glycol monoethyl acetate, hexane, cyclohexane, heptane, octane, benzene, chlorobenzene, chloroform, methylene chloride, and Diethyl ether or the like can be used.
[0029]
When forming the multilayer film 12 of core-shell fine particles in a larger area, a spin coating method can be used. Specifically, after the dispersion liquid of the core-shell fine particles 13 is dropped on the processing target substrate, the processing target substrate 11 is rotated at an appropriate rotation speed and dried to form the core-shell fine particle film 12. In this case, it is possible to arbitrarily change the number of layers of the core-shell fine particle film by controlling the concentration of the core-shell fine particle dispersion, the type of the solvent, or the spin speed. The concentration of the core-shell fine particles 13 can be appropriately selected within a range of 0.1 mg / ml to 100 mg / ml, and the higher the concentration, the more layers can be formed. In addition, the number of layers can be increased by using a solvent having a low boiling point of about 100 ° C. or less and easily evaporating. Such solvents include, for example, methanol, ethanol, hexane, benzene, ethyl acetate, chloroform, and the like. Further, the number of layers can be increased as the spin rotation speed is smaller. Specifically, this is the case at about 1000 rpm or less.
[0030]
Alternatively, a large-area core-shell fine particle film can also be prepared by immersing the work 11 in a dispersion of the core-shell fine particles 13 and then pulling the work 11 from there. Even in such a pulling method, the number of layers of the core-shell fine particle film can be arbitrarily changed by controlling the concentration of the core-shell fine particles 13, the type of the solvent, or the pulling speed of the substrate to be processed.
[0031]
As the core-shell fine particles, a block copolymer having a micelle structure as shown in FIG. 2 can also be used. In such a block copolymer, the first polymer block 17 existing at the center of the micelle structure corresponds to the core fine particles, and the second polymer block 18 existing outside the micelle structure corresponds to the shell layer. When the multilayer film 12 of the core-shell fine particles of the block copolymer is used, the multilayer film 12 can be formed on the workpiece 11 as shown in FIG. 3 by the above-described drying method, spin coating method, or pulling method. It is possible.
[0032]
When the core-shell fine particles 13 are made of a relatively strong material, the portion immediately below the second or more layers often has a small number of first shell layers or is hollow. Such a state causes a problem such as the dots of the second layer or more falling during the dry etching in the subsequent step of forming a mask pattern by dry etching. After applying the core-shell multilayer film, an annealing process is performed to thermoplastically deform the shell layer 13b so that the shell layer material is present below the second-layer core fine particles. it can. In this case, if the annealing temperature is equal to or higher than the glass transition point of the shell layer 13b, it is possible to cause sufficient thermoplastic deformation. For example, when the shell layer 13b is made of a polystyrene polymer having a glass transition point of 100 ° C., plastic deformation can occur at a temperature of 100 ° C. or higher.
[0033]
Alternatively, it is also effective to fill the cavity with a matrix material. In order to produce the multilayer fine particle film 12 in which the cavity is buried with the matrix material, the dispersion of the core-shell fine particles 13 may be mixed with the matrix material to form the multilayer fine particle film. The matrix material needs to be easily removed together with the shell layer 13b by performing dry etching using oxygen plasma or the like. Etching rate e for dry etching process of matrix material _m However, similarly to the shell layer 13b, the etching rate e of the core fine particles 13a is _c (√2 + √3), that is, the etching rate e of the matrix material _m And etching rate e of core fine particles _c It is preferable that a relationship represented by the following mathematical expression (4) is established between.
[0034]
e _m ≧ (√2 + √3) e _c (4)
At this time, the thickness t of the shell layer 13b _s And the radius r of the core fine particles 13a _c When the relationship represented by the following equation (1) is established, the core fine particles 13a are etched during the time for etching the shell layer 13b having a thickness from the uppermost surface of the fine particle multilayer film to the surface of the workpiece. Calculated on the condition that they do not disappear due to
[0035]
t _s > ($ 3-1) r _c (1)
As such a matrix, for example, polystyrene, polymethyl methacrylate, polyethylene, polybutadiene, polycarbonate, polyvinyl chloride, polyimide, and novolak resin can be used.
[0036]
After the multilayer fine particle film 12 is formed on the workpiece 11 by the above-described method, the shell layer 13b is removed by dry etching, and is supported by the material of the shell layer 13b as shown in FIG. An etching mask pattern 14 made of the core fine particles 13a is formed. For this purpose, the shape of the core fine particles 13a must be faithfully transferred to the shell layer 13b under the core fine particles. This can be realized by an etching method such as reactive ion etching or ion beam etching. In order to achieve etching with a higher aspect ratio by etching dry etching, it is preferable to reduce the pressure of the etching gas as much as possible. Specifically, it is desired to set the pressure to about 10 mTorr or less. It is also effective to perform etching while maintaining the sample, that is, the core-shell fine particles 13 at a low temperature, for example, 0 ° C. or lower.
[0037]
When the core-shell fine particles 13 are block copolymers, the first polymer blocks corresponding to the core fine particles contain metals and semiconductor atoms, and the second polymer blocks corresponding to the shell layers do not contain these metals and semiconductor atoms. Is preferred. By using such a material, when oxygen is used as an etching gas, the etching rate of the first polymer block corresponding to the core fine particles can be sufficiently reduced as compared with the second polymer block. .
[0038]
By dry-etching the workpiece 11 using the etching mask pattern 14 thus obtained, a fine pattern 15 having a high aspect ratio can be formed on the workpiece 11 as shown in FIG. Become. At this time, it is preferable that the etching rate of the shell layer 13 b with respect to the etching gas of the dry etching be sufficiently smaller than the etching rate of the workpiece 11. For example, when the shell layer 13b is made of polystyrene and the workpiece 11 is made of a metal such as Co or Cu, a fine pattern can be formed on the workpiece 11 by using chlorine as an etching gas.
[0039]
Reactive ion etching, ion beam etching, or the like can be employed for processing the workpiece 11. In a patterned medium that is a high-density recording medium, a magnetic body is used as a workpiece. For the etching of such a magnetic material, it is preferable to perform reactive ion etching using chlorine gas or a mixed gas of carbon monoxide and ammonia as an etching gas. Alternatively, it can be processed by ion beam etching using argon or neon gas as an etching gas. In the case where the workpiece 11 is etched, as in the case of etching when the etching mask pattern 14 is formed, the gas pressure can be as low as about 10 mTorr or less so that the processing can be performed with a higher aspect ratio. It is also effective to process the workpiece 11 while maintaining it at a low temperature of about 0 ° C. or less.
[0040]
The multilayer fine particle film 12 of core-shell fine particles can also be formed on the workpiece 11 via an intermediate layer. In the pattern forming method using the self-assembly of the fine particles, it is difficult to increase the aspect ratio of the etching mask because the fine particles are spherical with a small particle diameter. Such a problem can be solved by interposing an intermediate layer between the multilayer fine particle film 12 and the workpiece 11 and increasing the etching rate ratio between the core fine particles and the intermediate layer.
[0041]
FIG. 4 is a process sectional view illustrating a fine pattern forming method according to another embodiment of the present invention.
[0042]
First, as shown in FIG. 4A, an intermediate layer 20 made of a carbon-based organic polymer material or the like is applied on the substrate 11 to be processed. The reason why the carbon-based polymer material is used is to transfer the pattern of the core fine particles 13a to the intermediate layer 20 by oxygen plasma etching in a later step. As the carbon-based organic polymer material, for example, materials having high etching resistance such as polystyrene derivatives such as polystyrene and polyhydroxystyrene, polyvinyl naphthalene and derivatives thereof, novolak resins, and polyimides are preferable. When a multilayer film of core-shell fine particles is formed in a later step, it is preferable to cure the intermediate layer 20 after applying the intermediate layer so that the intermediate layer 20 is not dissolved by the solvent of the core-shell fine particle solution.
[0043]
A light-curing or thermosetting resin is mixed with the material of the intermediate layer, and the intermediate layer 20 can be cured by the action of light or heat. As the photocurable resin, for example, polystyrene, polybutadiene, polyisoprene, novolak resin, diazo resin, and the like can be used. As the thermosetting resin, for example, polyacrylonitrile derivative, polyamic acid, polyimide, polyaniline derivative, polyparaphenylene derivative, polycyclohexadiene derivative, polybutadiene, polyisoprene, and novolak resin can be used.
[0044]
In order to cure the polymer chain more efficiently, it is also effective to add a radical generator such as an organic peroxide and a crosslinking agent to the intermediate layer 20 to promote the crosslinking reaction and to cure. By using light curing and heat curing together, the curing reaction is further promoted, and the heat resistance and solvent resistance of the intermediate layer 20 are enhanced.
[0045]
The intermediate layer 20 can be applied by spin coating or the like after dissolving these materials in an appropriate solvent. As the solvent, for example, ethanol, methanol, propanol, ethyl lactate, ethyl acetate, xylene, tetrahydrofuran, toluene, propylene glycol monoethyl acetate, hexane, cyclohexane, heptane, octane, benzene, chlorobenzene, chloroform, methylene chloride, and diethyl ether Etc. can be used. The intermediate layer 20 supports an etching mask pattern when etching the workpiece 11. As described above, the diameter of the core fine particles is preferably 50 nm or less, and the size of the obtained dot pattern is also 50 nm or less. Therefore, assuming that the aspect ratio of the etching mask is at most about 100, the thickness of the intermediate layer 20 is desirably 5 μm or less. If the thickness is larger than that, the aspect ratio of the etching mask pattern to be formed becomes too large, and there is a possibility that a failure such as falling down may occur.
[0046]
As shown in FIG. 4B, a multilayer film 12 of core-shell fine particles is formed on the intermediate layer 20 by the above-described method or the like.
[0047]
Next, dry etching is performed to transfer the pattern of the core fine particles 13a to the shell layer 13b and the intermediate layer 20, thereby forming an etching mask pattern 21 as shown in FIG. Etching rate e for dry etching process of intermediate layer 20 _i Preferably satisfies the relationship represented by the following equation (3).
[0048]
e _i ≧ e _c e _s t _i / (2 (e _s − ($ 2 + $ 3) e _c ) R _c (3)
(In the above formula, t _i Is the thickness of the intermediate layer during the dry etching process. )
At this time, the thickness t of the shell layer 13b _s And the radius r of the core fine particles 13a _c When the relationship represented by the following equation (1) is established, the core fine particles 13a are etched during the time for etching the shell layer 13b having a thickness from the uppermost surface of the fine particle multilayer film to the surface of the workpiece. Calculated on the condition that they do not disappear due to
[0049]
t _s > ($ 3-1) r _c (1)
Since the etching rate of the intermediate layer is sufficiently higher than that of the core fine particles similarly to the shell layer, an etching mask pattern having a higher aspect ratio can be formed. In this case, the core fine particles supported by the intermediate layer material and the shell layer material become the etching mask pattern. A mask pattern having a high aspect ratio is particularly effectively used when a pattern is transferred onto a workpiece with higher accuracy and a higher aspect ratio.
[0050]
In order to obtain a higher etching rate ratio between the core fine particles 13a and the shell layer 13b and the intermediate layer 20, it is preferable to transfer the pattern by oxygen plasma etching.
[0051]
In order to form the etching mask pattern 21 as shown in FIG. 4C, the shape of the core fine particles 13a must be faithfully transferred to the shell layer 13b and the intermediate layer 20 under the core fine particles. . This can be realized by an etching method such as reactive ion etching or ion beam etching.
[0052]
By dry-etching the workpiece 11 using the etching mask pattern 21 thus obtained, a fine pattern 22 having a high aspect ratio can be formed on the workpiece 11 as shown in FIG. Become.
[0053]
Since the intermediate layer 20 is provided between the workpiece 11 and the multilayer fine particle film 12, it is possible to form an etching mask pattern having a very high aspect ratio by using the intermediate layer 20. Therefore, in this case, there is an advantage that the selectivity of the self-assembled core-shell fine particles 13 is widened.
[0054]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples of the present invention, but the present invention is not limited to these examples.
[0055]
(Example 1)
In the present embodiment, a fine pattern was formed on a workpiece according to the process shown in FIG.
[0056]
Core fine particles having a diameter of 10 nm were used as core fine particles, and core shell fine particles having a shell layer of 10 nm in thickness made of alkyl mercaptan were used. The core-shell fine particles were dispersed in hexane at a concentration of 5 mg / ml to prepare a dispersion.
[0057]
First, as shown in FIG. ₂ The above-mentioned dispersion liquid was spread on a substrate by spin coating, and rotated at 100 rpm and dried to form a multilayer fine particle film. Observation of the surface shape by SEM confirmed that a two-layer film of core-shell fine particles was formed.
[0058]
Next, oxygen plasma etching was performed to form an etching mask pattern 14 as shown in FIG. Specifically, reactive ion etching (RIE) was performed for 20 seconds under the conditions of an oxygen flow rate of 5 sccm, a total pressure of 5 mTorr, and an input RF power of 100 W.
[0059]
In addition, CHF ₃ Is used as an etching gas to perform plasma etching, and as shown in FIG. ₂ The pattern was transferred to the substrate. Specifically, CHF ₃ The reactive ion etching (RIE) was performed for 30 seconds at a flow rate of 5 sccm, a total pressure of 5 mTorr, and an applied RF power of 100 W. As a result, a fine pattern 15 was formed on the surface of the workpiece 11 as shown in FIG.
[0060]
The remaining etching mask pattern 14 was removed from the workpiece 11 by concentrated sulfuric acid treatment.
[0061]
FIG. 5 is an AFM image of the obtained sample surface. It was confirmed that circular dots having a diameter of 10 nm were independently close to each other, and that an uneven structure having a depth of 10 nm arranged in a hexagonal shape was formed.
[0062]
(Comparative example)
The same core-shell fine particles as in Example 1 described above were dispersed in hexane at a concentration of 2 mg / ml to prepare a dispersion.
[0063]
The obtained dispersion is treated with SiO 2 as a workpiece. ₂ It was spread on a substrate by spin coating, rotated at 100 rpm, and dried to form a fine particle film. Observation of the surface shape by SEM revealed that a monolayer film of core-shell fine particles had been formed.
[0064]
Next, an etching mask pattern was formed by oxygen plasma etching in the same manner as in Example 1 described above. Then, CHF ₃ Was used as an etching gas to perform plasma etching to transfer a pattern onto a workpiece. Finally, the etching mask pattern was removed by concentrated sulfuric acid treatment.
[0065]
FIG. 6 is an AFM image of the obtained sample surface. SiO ₂ It was confirmed that the dots formed on the surface of the substrate had a very small region where they were regularly arranged, and the regions where they were arranged also had large variations.
[0066]
(Example 2)
In the present embodiment, a fine pattern was formed on a workpiece according to the process shown in FIG.
[0067]
Gold fine particles having a diameter of 5 nm were used as core fine particles, and core-shell fine particles having a shell layer made of alkyl mercaptan and having a thickness of 5 nm were used. The core-shell fine particles were dispersed in hexane at a concentration of 15 mg / ml to prepare a dispersion.
[0068]
First, a CoCrPt alloy film having a thickness of 10 nm was formed on a glass disk by a sputter deposition method to prepare a workpiece 11.
[0069]
As shown in FIG. 4A, an intermediate layer 20 made of a novolak resin was applied on the workpiece 11 by spin coating, and then cured by heating at 200 ° C. in a nitrogen atmosphere for 30 minutes. The application conditions were adjusted so that the thickness of the intermediate layer 20 was 30 nm. Specifically, the thickness of the intermediate layer was controlled to 30 nm by spin-coating a propylene glycol monoethyl acetate solution having a concentration of 15 mg / ml at a rotation speed of 5000 rpm.
[0070]
On the intermediate layer 20, the above-mentioned dispersion liquid was developed by spin coating, rotated at 100 rpm, and dried to form a multilayer fine particle film 12 as shown in FIG. 4B. Observation of the surface shape by SEM confirmed that a three-layer film of core-shell fine particles was formed.
[0071]
Next, oxygen plasma etching was performed to form an etching mask pattern 21 as shown in FIG. Specifically, reactive ion etching (RIE) was performed for 40 seconds under the conditions of an oxygen flow rate of 5 sccm, a total pressure of 5 mTorr, and an applied RF power of 100 W.
[0072]
Further, plasma etching was performed using chlorine as an etching gas to transfer the pattern to the workpiece as shown in FIG. Specifically, reactive ion etching (RIE) was performed for 60 seconds under the conditions of a chlorine flow rate of 5 sccm, a total pressure of 5 mTorr, and an input RF power of 100 W. As a result, a fine pattern 22 was formed on the surface of the workpiece 11 as shown in FIG.
[0073]
The remaining etching mask pattern 21 was removed from the workpiece 11 by oxygen plasma processing.
[0074]
FIG. 7 is an AFM image of the obtained sample surface. It was confirmed that circular dots having a diameter of 5 nm were densely packed at an interval of 10 nm, and an arrayed magnetic dot structure having a depth of 10 nm was formed.
[0075]
(Example 3)
Core fine particles having a diameter of 10 nm were used as core fine particles, core-shell fine particles having a shell layer of 10 nm in thickness made of alkyl mercaptan were used, and polystyrene was used as a matrix material. The core-shell fine particles were dispersed in hexane at a concentration of 5 mg / ml, and this dispersion was mixed with a matrix material at 0.5 mg / ml.
[0076]
First, SiO 2 as a workpiece ₂ The above-described dispersion was spread on a substrate by spin coating, rotated at 100 rpm, and dried to form a multilayer fine particle film. Observation of the surface shape by SEM confirmed that a two-layer film of core-shell fine particles was formed.
[0077]
An etching mask pattern was formed by oxygen plasma etching. Specifically, reactive ion etching (RIE) was performed for 20 seconds under the conditions of an oxygen flow rate of 5 sccm, a total pressure of 5 mTorr, and an input RF power of 100 W.
[0078]
CHF ₃ Was used as an etching gas to perform plasma etching to transfer a pattern to a workpiece. Specifically, CHF ₃ The reactive ion etching (RIE) was performed for 1 minute at a flow rate of 5 sccm, a total pressure of 5 mTorr, and an applied RF power of 100 W. As a result, a fine pattern 15 was formed on the surface of the workpiece 11 as shown in FIG.
[0079]
The remaining etching mask pattern was removed from the workpiece 11 by concentrated sulfuric acid treatment.
[0080]
Observation of the sample surface thus obtained by AFM confirmed that circular dots each having a diameter of 10 nm independently approached each other, and that a concavo-convex structure having a depth of 20 nm arranged in a hexagonal shape was formed.
[0081]
Although the embodiments of the present invention have been described with reference to the specific examples, the present invention is not limited to these specific examples. Further, the method for forming a fine pattern of the present invention is not limited to the above-described patterned media, and a method capable of performing the same in other various uses and obtaining the same effect is also included in the scope of the present invention.
[0082]
In addition, all the fine pattern forming methods that can be implemented by a person skilled in the art by appropriately changing the design based on the above-described fine pattern forming method also belong to the scope of the present invention.
[0083]
【The invention's effect】
As described above, according to the present invention, there is provided a method for forming a highly regularly arranged fine pattern having a high aspect ratio on the surface of a workpiece.
[0084]
INDUSTRIAL APPLICABILITY The present invention can be suitably used for manufacturing, for example, high-density recording media, highly integrated electronic components, and the like, and its industrial value is enormous.
[Brief description of the drawings]
FIG. 1 is a process cross-sectional view illustrating a fine pattern forming method according to an embodiment of the present invention.
FIG. 2 is a schematic view showing a structure in a case where a core-shell structure is formed by a block copolymer.
FIG. 3 is a schematic diagram when a multilayer film is formed by a block copolymer.
FIG. 4 is a process sectional view illustrating a fine pattern forming method according to another embodiment of the present invention.
FIG. 5 is an AFM image of the surface of a sample manufactured in Example 1.
FIG. 6 is an AFM image of the surface of a sample manufactured in a comparative example.
FIG. 7 is an AFM image of the surface of a sample manufactured in Example 2.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Workpiece, 12 ... Multilayer fine particle film, 13 ... Core-shell fine particle, 13a ... Core fine particle, 13b ... Shell layer, 14 ... Etching mask pattern, 15 ... Fine pattern, 17 ... First polymer block, 18 ... Second Polymer block, 20 ... intermediate layer, 21 ... etching mask pattern, 22 ... fine pattern.

Claims (3)

A step of forming a multi-layer fine particle film by densely filling core-shell fine particles in which core fine particles are coated on a shell layer into two or more layers on a workpiece;
Performing dry etching on the multilayer fine particle film, forming an etching mask pattern including core fine particles supported by the material of the shell layer, and transferring the shape of the etching mask pattern to the workpiece; A method for forming a fine pattern, comprising a step of forming a fine pattern on the workpiece. Before forming the multilayer fine particle film on the workpiece, the method further comprises a step of forming an intermediate layer, and after the step of forming the etching mask pattern, dry-etching the intermediate layer with the etching mask pattern. The method according to claim 1, further comprising a step of patterning the fine pattern. The multilayer fine particle film is formed by using a dispersion containing the core-shell fine particles and a matrix material, the core-shell fine particles closely packed into the two or more layers and the matrix material filling the gaps between the core-shell fine particles, The pattern forming method according to claim 1, wherein the matrix material is processed by the dry etching to support the core fine particles together with the shell layer material to form the etching mask pattern.

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