JP5818252B2 - Manufacturing method of substrate with metal film pattern - Google Patents

Description

  The present invention relates to a method for manufacturing a substrate with a metal film pattern using a thermal nanoimprint lithography method, and a method for manufacturing a mold.

  The development of semiconductor devices that support an advanced information society is largely due to the progress of microfabrication technology, especially photolithography technology. Today's photolithography technology has been supported by exposure apparatus technology represented by a reduction projection exposure apparatus, resist material composed of a polymer and a photosensitive agent, and technological innovation in process development. However, there is a problem that the price of the exposure apparatus and the photomask becomes higher as the pattern becomes finer.

  Under such circumstances, nanoimprint technology that is excellent in cost without using expensive optical materials and capable of microfabrication is in the spotlight as the next generation lithography technology. The nanoimprint technology includes a thermal nanoimprint lithography method using a thermoplastic resin as a processing layer (Non-Patent Document 1, Patent Document 1) and an optical nanoimprint lithography method using a photocurable resin as a processing layer (Non-Patent Document 2). Can be divided roughly.

The pattern using the thermal nanoimprint lithography method is formed through the following processes, for example. First, a thermoplastic resin film is formed on the substrate as a layer to be processed, then softened by heating, and a mold serving as a mold is pressed. Thereby, a to-be-processed layer deform | transforms. Then, the unevenness | corrugation of a mold is transcribe | transferred to a to-be-processed layer by cooling and hardening a to-be-processed layer. Subsequently, the mold is released, and the remaining film remaining in the recesses of the layer to be processed is removed by reactive ion etching processing or UV-O ₃ processing. Thereafter, the pattern is transferred to the substrate by a dry or wet etching process using the layer to be processed as a mask. Note that a fine pattern may be formed by depositing metal or the like in the concave portion by a plating step, sputtering, or the like instead of the etching step.

  As a suitable material for thermal nanoimprint lithography, Nakagawa's research group has recently developed a photoreactive compound that can be firmly bonded via a chemical bond at the interface between a metal film and a thermoplastic resin. Proposed (Patent Document 2). In addition, a transparent conductive substrate (Patent Document 3) excellent in conductivity and capable of forming a metal wiring pattern and a wet etching substrate capable of preventing pattern defects in a wet etching process have been proposed (Patent Document 4). Moreover, it proposed about the fluorescent resist composition for thermal nanoimprint suitable for the residual film measurement and defect inspection of a thermal nanoimprint molding (patent document 5).

  The optical nanoimprint lithography method is different from the thermal nanoimprint lithography method in using a photocurable resin as a layer to be processed and having a process of curing the resin by light, but the basic process is different from the thermal nanoimprint lithography method described above. It is the same.

  By the way, in the nanoimprint technique, as described above, a mold of a mold is necessary. In the manufacture of a mold, a resist film pattern is usually formed by a photolithography method, an electron beam drawing method, or a laser drawing method, and then a substrate is processed by RIE or plating. Patent Document 6 proposes a method of manufacturing a mold by applying a positive resist on a substrate to be a mold, performing electron beam drawing to form a resist film pattern, and etching using this as a mask. . Patent Document 7 proposes a method in which a positive resist film pattern is formed in a pattern region, a negative resist layer is formed in a non-pattern region, and a mold is manufactured by electron beam drawing.

US Pat. No. 5,772,905 JP 2009-73809 A JP 2011-54345 A JP 2011-111636 A JP 2011-51153 A JP 2004-288845 A JP 2011-165980 A

S. Y. Chou, et al., Applied Physics Letters, (1995), 67, 3114-3116. J. Haisma, et al., J. Vac. Sci. Technol. B, B14, 4124-4128 (1996).

  When the photolithography method is adopted as a mold manufacturing method, there is a problem that it is not easy to produce a large mold. In addition, when manufacturing a mold having a pattern size of less than a micrometer, it is necessary to manufacture a photomask using a reduction projection exposure apparatus, and the mold becomes expensive unless the mold is mass-produced. There was also.

  Mold manufacturing by the electron beam drawing method is performed by, for example, applying a resist on a substrate, drawing the resist directly by an electron beam, patterning, and performing dry etching. Although the method by electron beam drawing can form an ultrafine structure of 4 nm level, it has a disadvantage of poor productivity. For example, it takes about one week to produce a 2-inch circular mold, although it varies depending on the apparatus and pattern shape. For this reason, it was particularly unsuitable for manufacturing a large mold.

  On the other hand, the mold production by the laser drawing method can form a pattern at a higher speed than the electron beam drawing. For this reason, it can be said that it is a method excellent in productivity. However, there is a limit to obtain a pattern of about several μm, and there is a problem that it is not suitable for microfabrication of less than a micrometer size.

  From the above situation, the nanoimprint technology is not satisfactory in both the pattern miniaturization and productivity, and there are still problems to be put into practical use. In particular, when it is desired to form a fine pattern on a large substrate, poor productivity has been a serious problem.

  The present invention has been made in view of the above problems, and a first object of the present invention is to use a thermal nanoimprint lithography method, while maintaining a good pattern shape, and more than the recess size of the concavo-convex pattern on the mold surface. An object of the present invention is to provide a method for manufacturing a substrate with a metal film pattern having a small pattern size. A second object of the present invention is to provide a method for manufacturing a recess having a pattern size smaller than the recess size of the uneven pattern on the mold surface to be a mold, or a mold having a convex portion, using a thermal nanoimprint lithography method. .

  The present inventor has intensively studied to achieve the above object, has found that the object of the present invention can be achieved by the following production method, and has completed the present invention. That is, the method for producing a substrate with a metal film pattern according to the present invention includes a step of forming a metal film on the substrate, and a hydrophobic polymer composed of a photoreactive adhesive layer and a thermoplastic resin as a main component on the metal film. And a step of adhering the photoreactive adhesive layer and the resist film by actinic ray irradiation of the photoreactive adhesive layer, and a mold surface with respect to the resist film. A step of forming a resist film pattern by transferring the concavo-convex pattern formed on, and a step of performing a residue treatment so that the resist film is removed in the concave portion of the concavo-convex pattern formed on the resist film pattern; Forming a metal film pattern by wet-etching the exposed metal film using the resist film pattern. The step of forming the metal film pattern includes a recess size of the concavo-convex pattern of the mold so that the metal film pattern has a reduced size in a plan view than a recess size of the concavo-convex pattern formed on the surface of the mold. This is based on a thermal nanoimprint lithography method including a step of performing a side etching of the metal film pattern by extending the wet etching processing time longer than obtaining a substantially equal metal film pattern.

  According to the method for manufacturing a substrate with a metal film pattern according to the present invention, a metal film pattern in which the size in plan view is downsized can be obtained with higher quality than the concave size of the concave and convex pattern of the mold. Conventionally, when obtaining a metal film pattern, a substantially 1: 1 pattern has been transferred to the uneven pattern of the mold. The main reason for this is that when the side etching is performed in the wet etching process, the resist film swells, resulting in a defective pattern shape of the metal film, or the wet etching chemical enters the interface between the metal film pattern and the resist film. This is because the film peels off and the metal film is disconnected. As a result of extensive studies by the present inventors, it is surprising that a photoreactive adhesive layer is interposed between the metal film and the resist film, and a hydrophobic polymer is used as the main component as the resist film. It was found that a high-quality pattern can be obtained even when side etching of the metal film pattern is performed.

  The method for producing a mold according to the present invention includes a step of obtaining a substrate with a metal film pattern by the method for producing a substrate with a metal film pattern according to the above aspect, and the metal film pattern formed on the substrate with the metal film pattern as a mask. And a step of excavation processing so as to form a recess or a through hole in the base constituting the base with the metal film pattern.

  According to the present invention, using the thermal nanoimprint lithography method, a method for producing a substrate with a metal film pattern having a metal film pattern having a pattern size smaller than the concave size of the concave / convex pattern on the mold surface while maintaining a good pattern shape There is an excellent effect that can be provided. In addition, the thermal nanoimprint lithography method can be used to provide a method of manufacturing a mold having a recess having a pattern size smaller than the recess size of the recess / projection pattern on the mold surface serving as a mold, or a mold having a projection. is there.

The typical sectional view of the base with a metal film pattern concerning a 1st embodiment. The flowchart figure of the manufacturing method of the base | substrate with a metal film pattern which concerns on 1st Embodiment. Sectional drawing of the manufacturing process of the base | substrate with a metal film pattern which concerns on 1st Embodiment. Sectional drawing of the manufacturing process of the base | substrate with a metal film pattern which concerns on 1st Embodiment. Sectional drawing of the manufacturing process of the base | substrate with a metal film pattern which concerns on 1st Embodiment. Sectional drawing of the manufacturing process of the base | substrate with a metal film pattern which concerns on 1st Embodiment. Sectional drawing of the manufacturing process of the base | substrate with a metal film pattern which concerns on 1st Embodiment. Sectional drawing of the manufacturing process of the base | substrate with a metal film pattern which concerns on 1st Embodiment. Sectional drawing of the manufacturing process of the base | substrate with a metal film pattern which concerns on 1st Embodiment. The typical sectional view of the mold concerning a 2nd embodiment. The flowchart figure of the manufacturing method of the mold concerning a 2nd embodiment. Sectional drawing of the manufacturing process of the mold which concerns on 2nd Embodiment. Sectional drawing of the manufacturing process of the mold which concerns on 2nd Embodiment. The typical sectional view of the mold concerning a 3rd embodiment. 2 is an SEM image of a substrate with a resist film pattern according to Example 1. FIG. 3 is an SEM image of a substrate with a same magnification-metal film pattern according to Example 1. FIG. 3 is an SEM image of a substrate with a metal film pattern according to Example 1. FIG. 4 is an SEM image of a substrate with a metal film pattern according to Example 2. FIG. 4 is an SEM image of a substrate with a metal film pattern according to Example 3. FIG. 4 is an SEM image of a substrate with a resist film pattern according to Example 4. FIG. 6 is an SEM image of a substrate with a same magnification-metal film pattern according to Example 4. 4 is an SEM image of a substrate with a metal film pattern according to Example 4. FIG. 6 is an SEM image of a substrate with a metal film pattern according to Example 5. FIG. 6 is an SEM image of a substrate with a metal film pattern according to Example 6. FIG. 10 is an SEM image of a substrate with a resist film pattern according to Example 7. FIG. 8 is an SEM image of a substrate with an equal magnification-metal film pattern according to Example 7. FIG. 10 is an SEM image of a substrate with a metal film pattern according to Example 7. FIG. 10 is an SEM image of a substrate with a metal film pattern according to Example 8. FIG. 10 is an SEM image of a substrate with a resist film pattern according to Example 9. The SEM image of the base | substrate with a 1x-metal film pattern which concerns on Example 9. FIG. 10 is an SEM image of a substrate with a metal film pattern according to Example 9. FIG. 10 is an SEM image of a substrate with a metal film pattern according to Example 10. FIG. The optical microscope image of the base | substrate with a 1x-metal film pattern which concerns on Example 11. FIG. 10 is an optical microscope image of a substrate with a metal film pattern according to Example 11. FIG. The optical microscope image of the base | substrate with a metal film pattern which concerns on Example 12. FIG. The optical microscope image of the base | substrate with a 1x-metal film pattern which concerns on Example 13. FIG. The optical microscope image of the base | substrate with a metal film pattern which concerns on Example 13. FIG. The light transmission spectrum of the base | substrate with a metal film pattern which concerns on Example 13. FIG. The light transmission spectrum of the base | substrate with a metal film pattern which concerns on Example 11 and Example 12. FIG.

  Hereinafter, an example of an embodiment to which the present invention is applied will be described. It goes without saying that other embodiments may also belong to the category of the present invention as long as they match the gist of the present invention. Moreover, the size and ratio of each member in the following drawings are for convenience of explanation, and are different from actual ones. Moreover, the same code | symbol is attached | subjected to the same element and the description is abbreviate | omitted suitably.

[First Embodiment]
The method for manufacturing a substrate with a metal film pattern according to the first embodiment is manufactured by an interfacial chemical bonding type thermal nanoimprint lithography method. FIG. 1 is a schematic cross-sectional view of a substrate with a metal film pattern manufactured by the method for manufacturing a substrate with a metal film pattern according to the first embodiment. The substrate 1 with a metal film pattern includes a substrate 10 and a metal film pattern 21.

  The use of the substrate 1 with a metal film pattern is not particularly limited, and can be used without limitation for various uses. For example, it can be used for manufacturing a mold for nanoimprint technology. Specifically, a predetermined concavo-convex structure is excavated by etching or the like in a place that is not masked by the metal film pattern 21 of the substrate 1 with the metal film pattern, and the metal film pattern is dissolved and removed by wet etching to form the surface of the substrate 1. A mold is manufactured by forming an uneven structure. Detailed examples will be described in the second and third embodiments.

  Other uses of the substrate 1 with a metal film pattern include a wiring board for electronics, an electromagnetic wave control filter, a photomask, a substrate with a light shielding layer, an antistatic film, a wire grid, and various antennas. More specifically, it can be applied to a common electrode or conductive light shielding film of a substrate used in a flat panel display such as a liquid crystal display or a plasma display, or can be used as an electrode of a solar cell or a touch panel. Moreover, it can apply to electromagnetic wave control filters, such as a flat panel display, a solar cell, and various touch panels, or can utilize as photomasks, such as photolithography. Moreover, you may utilize the refined | miniaturized metal film pattern as a transparent conductive substrate.

  The material of the substrate 10 is not particularly limited as long as it has a glass transition temperature higher than the glass transition temperature of a thermoplastic resin to be heat-molded to be described later. Examples thereof include inorganic substances and inorganic oxides such as silicon, glass, quartz, alumina, and barium titanate, or resins such as epoxy resins, phenol resins, polyimide resins, polyester resins, and polyphenylene oxide resins. The substrate 10 may be a single layer, a laminate of the same or different materials, or a material selected from the group consisting of two or more composite materials. As the composite material, known materials can be used without limitation. For example, a composite material in which glass fibers are hardened with an epoxy resin, or a composite material in which a phenol resin (for example, Bakelite (registered trademark)) using phenol and formaldehyde as raw materials is laminated can be given.

  In the case where the substrate 1 with a metal film pattern is used for a wiring board for electronics, the substrate 10 is made of an inorganic material such as silicon, glass or quartz, or a heat resistant organic material such as polyimide, from the viewpoint of smoothness, low expansion coefficient and insulation. Materials are generally used. In the case of flexible wiring board applications, the substrate 10 is generally made of polyester resin, polyphenylene oxide resin, or a composite material of glass fiber and epoxy resin. In the case of a photomask or optical nanoimprint mold application, quartz or the like is preferably used as the substrate 10 in terms of linear expansion coefficient and ultraviolet transmittance. In order to obtain a transparent conductive substrate, glass or plastic having a high visible light transmittance, a silicon wafer having a high infrared transmittance, or the like is preferably used. The substrate 10 used for a transparent conductive substrate preferably has a total light transmittance in the visible light region of 50% or more.

  The shape of the substrate 10 may be a plate shape, a sheet shape, or a film shape, and may be a flat shape or a curved shape. Although the thickness of the substrate 10 may be arbitrary, it is considered that the accuracy of pattern transfer does not deteriorate due to distortion of the substrate caused by various film formations or thermal history of processes.

  The material of the metal film pattern 21 is not particularly limited as long as it is a material that can be adhered to the photoreactive adhesive layer described later. For example, aluminum, copper, silver, gold, platinum, zinc, tantalum, titanium, molybdenum, chromium, nickel, palladium, rhodium, iron, tin, or an alloy containing these metals as a main component can be used. For low resistance applications, gold, silver, copper and the like are preferred. The film thickness of the metal film pattern 21 is not particularly limited, and can be appropriately selected depending on the application. For example, it is about 10 to 500 nm. The metal film pattern 21 may be a single layer or a laminate of the same or different materials.

  The shape and size of the metal film pattern 21 are not limited and can be designed as appropriate. The pitch width between the metal film patterns 21 is not limited. For example, the line width of the metal film pattern is 10 nm to 2 μm.

  In the substrate 1 with a metal film pattern, members such as an insulating film other than the substrate 10 and the metal film pattern 21 can be arbitrarily disposed. For example, a conductive film pattern such as another metal film, a semiconductor film pattern, an insulating protective film, or the like may be formed on the metal film pattern 21. In addition, a barrier metal (for example, TiN, WN, Ti, TaN, Ta, etc.) for preventing mutual diffusion between the base 10 and the metal film pattern 21 is provided under the metal film pattern 21, or adhesion is ensured. For this purpose, Cr, Ti, etc. may be provided. When the substrate 10 is a semiconductor substrate or the like, it is possible to prevent a large parasitic capacitance from being generated between the metal film pattern 21 and the substrate 10 by providing an insulating film. As the insulating film, known materials can be used without limitation. Examples thereof include silicon oxide, BPSG (Boron Phosphorus Silicon Glass), a high-k material having a high dielectric constant, and a low-k material having a low dielectric constant. The insulating film may be a single layer or a laminated body.

  Next, a method for manufacturing a substrate with a metal film pattern will be described. FIG. 2 is a flowchart of a method for manufacturing a substrate with a metal film pattern according to the first embodiment, and FIGS. 3A to 3G are cross-sectional views showing manufacturing steps of the substrate with a metal film pattern according to the first embodiment.

  The manufacturing method of the base | substrate with a metal film pattern which concerns on 1st Embodiment consists of at least the following steps, as shown in FIG. First, the metal film 20 is formed on the substrate 10 (step 1, FIG. 3A). Next, the photoreactive adhesive layer 30 and the hydrophobic resist film 40 are formed in this order on the surface of the metal film 20, and the photoreactive adhesive layer 30 has an adhesive property by actinic ray irradiation. Is expressed (step 2, FIG. 3B).

  Thereafter, the concavo-convex pattern is transferred to the formed resist film 40 by heat molding using the mold 50 having the concavo-convex pattern to obtain a resist film pattern 41 (step 3, FIG. 3C, FIG. 3D). Thereafter, residue removal (residual film removal) is performed in order to expose the metal film surface in the concave portions of the concave-convex pattern formed in the resist film 40 (step 4, FIG. 3E). Next, a metal film pattern is obtained by a wet etching process using the resist film pattern 41 as a mask (step 5, FIG. 3G). According to the conventional method, a metal film pattern having substantially the same pattern size as the convex portion of the resist film 40 (or the concave portion of the mold 50) is formed. On the other hand, according to the present invention, the wet etching process is further continued on the metal film pattern having substantially the same pattern size as the resist film 40. Here, for convenience of explanation, a metal film pattern having substantially the same size as the unevenness of the mold 50 is referred to as a 1 × -metal film pattern 22 (see FIG. 3F).

  In the present invention, since the wet etching process is further performed on the equal magnification-metal film pattern 22, the equal magnification-metal film pattern 22 is side-etched. Thereby, downsizing of the side wall of the equal-size metal film pattern 22 occurs. In other words, the pattern size in plan view of the metal film disposed below the resist film pattern 41 becomes smaller, and a finer pattern can be obtained. Through these steps, the metal film pattern 21 is obtained.

  Depending on the application, the resist film pattern 41 and the photoreactive adhesive layer 31 and / or the resist film pattern 41 may be left. However, in the first embodiment, the resist film pattern 41, the photoreactive property is subsequently used. By removing the adhesive layer pattern 31, the substrate 1 with a metal film pattern shown in FIG. 1 is obtained. When a metal oxide is present on the surface of the metal film pattern 21, the metal oxide may be removed simultaneously or sequentially with the photoreactive adhesive layer 30 for the purpose of realizing a reduction in resistance of the metal film pattern 21. . Hereinafter, the details of each step and the reason why fine patterning is possible will be described.

  In step 1, before the metal film 20 is formed on the substrate 10, the surface of the substrate 10 is usually cleaned by cleaning the substrate 10 by a cleaning process such as oxygen reactive ion etching or ultraviolet / ozone. The method for forming the metal film 20 is not particularly limited, and any known method can be used without limitation. For example, a dry plating method such as a sputtering method or a vacuum deposition method, an electroplating method, a wet plating method such as an electroless plating method for growing a metal to be plated, and the like as a nucleus for plating growth of tin, palladium or the like. . From the viewpoint of forming a dense film and obtaining a highly accurate fine pattern, a sputtering method, an electron beam evaporation method, or the like is preferable.

  As described above, the material of the metal film 20 may have a metal oxide formed on the surface thereof, and metals that are suitably applied in various applications can also be suitably applied in the present invention. Chromium, gold, and the like suitable for mold use used in the nanoimprint technology can be suitably applied to the present invention. Also, for example, silver suitably used for electrode applications such as solar cells and touch panels, copper and aluminum suitably used for wiring applications, chromium suitably used for light shielding layers of photomasks and flat panel displays, and electromagnetic wave control filters Silver, platinum, gold, and the like that can be suitably applied for use can also be preferably applied in the present invention.

  The film thickness of the metal film 20 can be appropriately designed according to the application and is not particularly limited. The preferable range of the film thickness cannot be generally described because it can vary depending on the material used and the pattern size. However, in consideration of the etching time, it is preferably 1 μm or less, and 5 nm or more from the viewpoint of the smoothness of the film surface. Is preferred.

  In Step 2, the photoreactive adhesive layer 30 is disposed between the metal film 20 and the resist film 40 and plays a role of firmly bonding to these. The photoreactive compound that forms the photoreactive adhesive layer 30 is not particularly limited as long as it satisfies the following conditions. That is, (1) the metal surface of the metal film 20 or the metal oxide layer formed on the surface of the metal film 20 chemically reacts to show good adhesion, and (2) the activity of the photoreactive adhesive layer 30 Any compound can be used without limitation as long as it is a compound having good adhesion to the upper resist film 40 by irradiation with light. The photoreactive adhesive layer is preferably a molecular-sized thin film from the viewpoint of microfabrication, and is preferably an adsorption monomolecular film. The actinic ray band of the photoreactive compound is not particularly limited, but the ultraviolet ray band is preferable from the viewpoint of developing the adhesion effect of the photoreactive adhesive layer in a short time.

  In the first embodiment, a known method such as a liquid phase method or a gas phase method can be used as a method of forming the photoreactive adhesive layer 30 on the metal film 20. For example, first, the metal film 20 is subjected to UV / ozone treatment to clean the surface of the metal film 20. Next, in the liquid phase method, a solution in which a photoreactive compound is dissolved in a solvent is formed on a metal film by spin coating, dipping, spray coating, flow coating, roll coating, die coating, or the like. After the membrane / reaction, a method of evaporating the solvent component under blowing, heating, or reduced pressure can be used. In order to form an adsorption monomolecular film, it is desirable to evaporate the solvent after washing the surface of the metal film 20 with a clean solvent after the reaction.

The solvent used for the photoreactive compound-containing solution may be any solvent that dissolves the photoreactive compound and does not react with the photoreactive compound. Ethanol and toluene are preferable from the viewpoint of the working environment.
In a solution in which a photoreactive compound is dissolved in a solvent, the concentration of the photoreactive compound is usually in the range of 0.0001 to 0.1 mol / dm ³ . By setting the concentration to 0.001 mol / dm ³ or more, the layer of the photoreactive compound can be formed uniformly. Further, when the concentration is 0.1 mol / dm ³ or less, a sufficient effect is obtained and it is economical.

  In the case of using the vapor phase method, for example, there is a method in which the base 10 having the metal film 20 and the photoreactive compound are put in the same container, sealed in a nitrogen atmosphere, and heated. The heating temperature is 140 to 250 ° C., preferably without any problem unless the photoreactive compound is volatilized and decomposes. The heating time is preferably 5 to 120 minutes.

  The resist film 40 is a layer to be processed for obtaining the metal film pattern 21 and plays a role as a mask pattern. The resist film 40 is obtained by coating at least a pattern formation region on the upper layer of the photoreactive adhesive layer 30. The resist film 40 is a hydrophobic polymer for enabling a fine pattern and uses a thermoplastic resin as a main component.

Examples of the photoreactive compound used for the preferred photoreactive adhesive layer 30 include thiol compounds having a benzophenone skeleton such as the following compound (1) and silane compounds having a benzophenone skeleton such as the following compound (2).
N in the formula represents an integer of 1 to 20.
In the compound (1), n = 10 is most preferable from the viewpoint of easy availability of raw materials, ease of synthesis, photoreactivity with a thermoplastic resin, and adhesion to a metal film, and specifically, Is particularly preferably 4- (10-mercaptodecyloxy) benzophenone.

^Wherein, R 1 to R ³ represents each independently a hydrogen group, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, an isocyanato group or a chloro group. At least one of R ^{1 to} R ³ is an alkoxy group having 1 to 3 carbon atoms, an isocyanato group, or a chloro group. n represents an integer of 1 to 20.
The reactive silyl group (—SiR ¹ R ² R ³ ) in the above formula is a trimethoxysilyl group, a dimethoxyhydrosilyl group, a dimethoxymethylsilyl group, a trichlorosilyl group, a dichloromethylsilyl group, a chlorodimethylsilyl group, or a triisocyanato. It is preferably a group, and particularly preferably a trimethoxysilyl group.
In the compound (2), n = 3 is most preferable from the viewpoints of availability of raw materials, ease of synthesis, photoreactivity with a thermoplastic resin, and adhesion to a metal film, and R ¹ , R ² and R ³ are methoxy groups, and specifically, 4-{[(3-trimethoxysilyl) propyl] oxy} benzophenone is particularly preferably used. These photoreactive compounds can be produced by known methods described in Patent Document 2, Patent Document 4, and the like.

  Compounds (1) and (2) do not have a substituent at the 2-position of the benzophenone skeleton. Therefore, the hydrogen abstraction reaction by radicals can proceed not only within the molecule but also between the molecules. More specifically, irradiation with ultraviolet rays excites the carbonyl group of the benzophenone skeleton in compounds (1) and (2) to generate a biradical. The radical generated on the oxygen atom of the benzophenone skeleton quickly extracts a hydrogen atom from the hydrocarbon group of the hydrophobic polymer forming the resist film 40 and changes to alcohol. On the other hand, radicals generated on carbon of the benzophenone skeleton recombine with radicals generated on the hydrocarbon of the resin forming the resist film to form a covalent bond. Thereby, in the compound (1), the thiol group is chemically adsorbed to the metal film 20 and the benzophenone group can form a covalent bond with the resist film 40 at the interface. In the compound (2), the reactive silyl group is adsorbed to the metal film 20 having a metal oxide film covered with a hydroxyl group to cause a hydrolysis reaction and a subsequent condensation reaction to be chemically adsorbed, and benzophenone. The group can form a covalent bond with the resist film 40. As a result, the metal film 20 and the resist film 40 are chemically and firmly bonded via the photoreactive adhesive layer 30.

On the surface of the metal film 20, a metal oxide layer that is naturally formed in the air after film formation may be formed. When there is no metal oxide layer on the surface of the metal film 20 (for example, gold), a photoreactive adhesive layer is formed from a photoreactive compound containing a thiol group, as in Japanese Patent Application Laid-Open No. 2009-73809 of Patent Document 2. It is preferable to make it. When there is a metal oxide layer on the surface of the metal film 20 (for example, chromium, copper, silver), a reactive silyl group such as a trimethoxysilyl group is disclosed, as in JP 2011-111636 A. It is preferable to form a photoreactive adhesive layer from a photoreactive compound containing. In addition, the photoreactive compound containing a thiol group can also be applied suitably for silver. When a photoreactive adhesive layer is formed from the photoreactive compound containing the thiol group, a gas phase method or a liquid phase method is preferable. When a methoxy group that is the reactive silyl group is used, an adsorption unit is used. From the viewpoint of facilitating the formation of a molecular film, the vapor phase method is preferable to the liquid phase method.
It should be noted that the final surface of the metal film pattern 21 obtained through the manufacturing method of the present invention may or may not have a metal oxide. That is, the metal film pattern 21 finally obtained may be substantially free of metal oxide on the surface.

  As materials for forming the hydrophobic polymer, (1) a room temperature solid polymer having hydrophobicity, (2) soluble in a solvent, and (3) a polymer insoluble in a chemical used for wet etching. Use. Examples include polymethyl methacrylate (PMMA), polystyrene, polyvinyl toluene, polybenzyl methacrylate, polycarbonate, low density polyethylene, high density polyethylene, polypropylene, polyvinyl chloride, cyclic polyolefin, ABS (Acrylonitrile Butadiene Styrene) resin, AS (Acrylonitrile Styrene). ) Resins. These can be used alone or blended. Moreover, the copolymer polymer which has these as main structures can also be used suitably.

  From the viewpoint of being inexpensive and easily available, polystyrene and polymethyl methacrylate polymers are preferred. The “polystyrene-based” represents a polymer having a polystyrene skeleton as a main structure, a polymer having a polystyrene skeleton as a main component, a polymer having a polystyrene skeleton as a main component of a copolymer, and modified polystyrene. Moreover, a nonpolar polymer is preferable from the viewpoint of high chemical resistance of the resist film pattern during wet etching. Examples of such polymers include polystyrene polymers, polyvinyl toluene polymers, and cyclic polyolefin polymers. When using thermoplastic resins composed of these hydrocarbon groups, it is difficult for the wet etching solution to penetrate into the resist due to its low water absorption, so it is possible to reduce the resist film thickness. It is possible to shorten the molding time in molding, improve the stirring efficiency of the wet etching solution, and produce a metal film pattern with good rectangularity.

In the first embodiment, the resist film 40 is formed by, for example, using a solution obtained by dissolving a hydrophobic polymer in a solvent as a spin coating method, a dipping method, a spray coating method, a flow coating method, a roll coating method, or a die coating method. The film can be formed by, for example, evaporation, and the solvent can be evaporated under blowing, heating, or reduced pressure.
The solvent only needs to dissolve the hydrophobic polymer to be used, and examples thereof include methyl ethyl ketone, cyclohexanone toluene, and xylene.
In addition to the hydrophobic polymer and the solvent, the composition for forming the resist film 40 may appropriately contain an additive. For example, a surfactant, a leveling agent or the like may be added to improve the coating properties on the substrate, or a fluorescent material for shape inspection may be added. Examples of these surfactants and leveling materials include ionic or nonionic surfactants, silicone derivatives, and fluorine derivatives. Examples of fluorescent materials include acridine fluorescent materials, anthracene fluorescent materials, rhodamine fluorescent materials, pyromethene fluorescent materials, and perylene fluorescent materials.

  In a solution in which a hydrophobic polymer is dissolved in a solvent, the concentration of the hydrophobic polymer is usually in the range of 0.1 to 10% by mass. When the concentration is lower than 0.1% by mass, the thickness of the hydrophobic polymer becomes too thin, and it may not function as a resist. If the concentration is higher than 10% by mass, the film thickness may not be maintained.

  The weight average molecular weight of the hydrophobic polymer that is the main component of the resist film 40 is preferably 5,000 to 1,000,000 g / mol, and particularly preferably 20,000 to 500,000 g / mol. . When the molecular weight is less than 5,000 g / mol, when the resist film 40 has a thickness of about 200 nm, the chemical solution for wet etching may penetrate and the function as a mask may be deteriorated. When the molecular weight is 1,000,000 g / mol or higher, the viscosity is high even at the glass transition temperature or higher, and it is difficult to perform heat molding at high speed.

  The thickness of the resist film only needs to be applicable to wet etching described below, and the thickness is not limited, but from the viewpoint of the protective ability of the metal film 20 and the ease of removal when removing the hydrophobic polymer, 0.05-2 micrometers is preferable and 0.1-1.0 micrometer is more preferable. The hydrophobic polymer may be composed of two or more layers. For example, the hydrophobic polymer layer may be formed again after irradiating the substrate for wet etching described later with ultraviolet rays.

  Adhesive expression of the photoreactive adhesive layer 30 is performed by irradiating actinic rays of the photoreactive adhesive layer. In the case of benzophenone-based compounds such as compounds (1) and (2), it is usually preferable to irradiate with ultraviolet rays having a wavelength of 200 to 400 nm. By this ultraviolet irradiation, the metal film 20 and the resist film 40 are chemically and firmly bonded via the photoreactive adhesive layer 30.

  As a light source for ultraviolet irradiation, for example, a low pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, an Hg-Xe lamp, or a halogen lamp can be used. An off filter or the like can be used. A wavelength of 200 nm or more is preferable because the transmittance to the hydrophobic polymer is high and the light source used is inexpensive. A wavelength of 400 nm or less is preferable because a photo-induced radical derived from a benzophenone structure can be efficiently formed. It is particularly preferable to irradiate ultraviolet rays having a wavelength of 254 nm emitted from a low-pressure mercury lamp which is a relatively inexpensive light source.

The exposure amount of ultraviolet light having a wavelength of 254 nm is preferably 0.5 to ⁵ J / cm ² . The irradiation energy of ultraviolet rays is usually 0.1 to 5 J / cm ² at a detection wavelength of 254 nm. When the irradiation energy of ultraviolet rays is less than 0.1 J / cm ^2, the chemical adhesion of the photoreactive adhesive layer 30 between the metal film 20 and the resist film 40 may be insufficient, and the resist film 40 is molded by thermal nanoimprinting. Sometimes, pattern defects of the resist film may occur due to dewetting. In addition, when the irradiation energy of ultraviolet rays is 5 J / cm ² or more, the depolymerization of the hydrophobic polymer constituting the resist film occurs, resulting in a decrease in the resist function against wet etching based on the decrease in the molecular weight. The cross-linking reaction may occur, and heat molding may become difficult based on the increase in molecular weight.

  When the transmittance of the substrate 10 with respect to the wavelength of 254 nm is low, after the resist film 40 is formed, the photoreactive adhesive layer 30 is irradiated with the actinic ray of the photoreactive adhesive layer 30 from the resist film 40 side. When the transparency of the substrate 10 with respect to the wavelength of 254 nm is high, the photoreactive adhesive layer 30 may be irradiated from the substrate 10 side. If the resist film 40 has poor light transmittance for actinic rays, the resist film 40 having a thickness capable of transmitting actinic rays is formed, and then irradiated with ultraviolet rays. A resist film 40 having a thickness suitable for exhibiting a resist function may be formed.

  In step 3, the concavo-convex pattern is transferred to the formed resist film 40 by heat molding using the mold 50 in which the concavo-convex pattern is formed to obtain a resist film pattern 41. A known method can be used as the heat molding method, and examples include parallel plate type one-to-one transfer, roll-to-roll, and sheet-to-sheet methods. A mold 50 as shown in FIG. 3C is prepared. Next, the resist film 40 is softened by heating at a temperature equal to or higher than the glass transition temperature of the hydrophobic polymer constituting the resist film, and the mold 50 is pressed. Thereby, the resist film 40 which is a layer to be processed is deformed. Thereafter, the unevenness of the mold 50 is transferred to the resist film 40 by cooling to below the glass transition temperature and solidifying the resist film 40. Then, the mold 50 is released. Through these steps, a resist film pattern 41 is obtained.

The mold 50 forms a concavo-convex pattern pattern for thermal nanoimprinting by processing the surface of a flat plate having a material such as silicon oxide, synthetic silica, fused silica, quartz, nickel on the surface by a known semiconductor micromachining technique. Can be prepared. For example, in the case of silicon oxide having a smooth surface, synthetic silica, fused silica, or quartz, a positive resist is applied and laser drawing is performed on the resist by a laser drawing apparatus. Thereafter, when development is performed, the resist of the laser irradiation portion is removed, and the resist of the laser non-irradiation portion on the flat plate remains. By dry etching such as CHF ₃ / O ₂ plasma, SiO _X is etched using the positive image of the resist as an etching mask for dry etching. Then, a recess can be formed on the surface of the flat plate by immersing in a stripping solution to remove the positive image of the resist and washing. From the viewpoint of promoting the release property of the resist, a treatment with a release agent such as a fluorocarbon-containing silane coupling agent may be performed.

  According to the laser drawing method, the mold production time can be greatly shortened, and therefore, it is particularly suitable for use in increasing the mold area. Further, a contact mask type photolithography method or the like can also be suitably applied. Further, an electron beam drawing method may be applied. In any method, by using the manufacturing method according to the first embodiment, it is possible to obtain a metal film pattern having a finer pattern size than the concave size of the concave / convex pattern on the surface of the mold. Among these, according to the method of manufacturing a mold 50 having a micrometer-sized uneven pattern on the surface by a laser drawing method to obtain a submicron-sized metal film pattern, productivity and microworkability including cost performance are improved. Very good in terms of view.

  The mold 50 manufactured in this way can be used as a mold as it is, but after a metal film such as nickel is formed on the surface of the mold, the metal film such as nickel is further thickened using an electroforming process technique. It can also be a coated mold. Further, after a metal film such as nickel is formed on the surface of the flat plate by a sputtering method, image formation may be performed using a photoresist or an electron beam resist. Further, by making the metal film thicker by electroforming process technology and performing surface polishing and resist removal, it is possible to use a cheaper nickel mold.

  As the thermal nanoimprint apparatus, a known apparatus can be used. For example, what is provided with a heating-cooling part, a pressurization part, and a pressure reduction part can be used. The heating / cooling unit includes a stage including a heater and a water cooling structure, and a substrate having a resist film is placed on the stage and heated to soften and cool the resist film. In the pressurizing unit, a mold having a concavo-convex pattern is pressed against a substrate having a resist film. The concavo-convex pattern is transferred by pressurizing the fine concavo-convex structure of the mold onto the softened substrate of the resist film. In the decompression unit, when the mold is pressed against the substrate, the decompression state is set. Thereby, a resist film can be efficiently made to follow the uneven | corrugated pattern of a mold.

  Next, the substrate with the resist film irradiated with ultraviolet rays (FIG. 3B) is placed on the heating / cooling stage of the thermal nanoimprint apparatus. And it heats at 20-100 degreeC temperature higher than the glass transition temperature of the thermoplastic resin which forms a resist film (heating process). By heating at a temperature 20 ° C. or more higher than the glass transition temperature of the thermoplastic resin, the thermoplastic resin becomes a rubber state and is sufficiently softened, so that the edge portion of the transferred pattern can be prevented from being rounded. Next, by heating at a temperature of 100 ° C. or less from the glass transition temperature of the thermoplastic resin, it is possible to prevent the resin from contracting significantly during cooling after the resist film pattern transfer. For this reason, it is possible to prevent the line width of the formed resist film pattern from being reduced.

  Next, the concave / convex pattern of the mold 50 is transferred to the resist film 40 by pressing the mold 50 having the concave / convex pattern against the resist film 40 (pressing step) and holding the mold 50 for a certain time (holding step). The pressing pressure of the mold 50 is not particularly limited, but is generally 1 to 100 MPa, preferably 5 to 20 MPa. The pressing time of the mold 50 is generally 1 second to 10 minutes, preferably 15 to 120 seconds. It is preferable to maintain a reduced pressure between the mold 50 and the sample during pressing. As a result, the resist film 40 can efficiently follow the fine concavo-convex pattern of the mold 50, and patterning with higher accuracy is possible. Thereafter, the temperature is lowered below the glass transition temperature of the thermoplastic resin which is a hydrophobic polymer forming the resist film 40 (cooling step). Next, the mold 50 is released from the resist film pattern 41 (release process). Thereby, a resist film pattern 41 to which the uneven pattern of the mold 50 is transferred is obtained.

In step 4, the residue remaining in the recesses of the resist film pattern 41 is removed. There is no particular limitation on the removal method, but etching by oxygen reactive ion etching treatment, UV-O ₃ treatment, or the like can be easily removed. In addition, when removing the resist film pattern 41 of this recessed part, the photoreactive adhesive layer 30 of a recessed part may be removed simultaneously, and the photoreactive adhesive layer 30 may remain | survive.

In step 5, a pattern is formed on the metal film 20 by a wet etching process using the resist film pattern 41 as a resist mask. The metal film pattern 21 is formed by removing the exposed portion of the metal film 20 by wet etching. The wet etching method is not particularly limited, and can be performed using a wet etching solution used in a conventional subtractive method. The type of wet etching solution can be selected according to the type of metal. For example, when the metal is gold or silver, an aqueous solution containing iodine / potassium iodide is preferably used. When the metal is copper, an aqueous solution containing ferric chloride (FeCl ₃ ), cupric chloride (CuCl ₂ ), Cu (NH ₃ ) ₄ Cl ₂ is preferably used. When the metal is chromium, nitric acid is mainly used. The etching solution contained in is preferably used.

  As the wet etching method, for example, a wet etching solution is sprayed on the exposed metal film 20 not masked by the resist film pattern 41 at a temperature of room temperature to 50 ° C., or the substrate is immersed in the wet etching solution to form the metal film. It may be performed by etching 20.

In the present invention, as described above, the same-size metal film pattern 21 is side-etched so that the pattern size of the metal film 20 disposed below the convex pattern of the resist film pattern 41 is smaller. When the resist film pattern 41 is formed with a line & space of 1 μm (1: 1), for example, when a metal film pattern is formed with a reduction rate of 80% or less, when the line width is 1 μm, the line has a size of 800 nm or less. It means forming. Further, in the case of a size having an area of 1 μm ² , forming a metal film pattern with a reduction rate of 80% or less means forming with a size of 800 nm ² or less.

  The reduction size of the metal film pattern 21 relative to the recess size of the recess pattern of the mold 50 is preferably reduced to a reduction rate of 90% or less, and preferably reduced to a reduction rate of 70% or less, from the viewpoint of fine processing. It is more preferable to reduce the ratio to 55% or less. The lower limit of the reduction ratio is not particularly limited as long as the resist film pattern 41 is not tilted and the metal film pattern 21 is not defective. The collapse of the resist film pattern 41 is largely dependent on the pattern shape and cannot be generally stated, but the reduction ratio is preferably 10% or more.

  After the metal film pattern 21 is formed, a step of peeling the photoreactive compound layer 30 and the resist film pattern 41 is performed as necessary. The solvent used for solvent cleaning is not particularly limited as long as it can dissolve the photoreactive compound layer and the resist film pattern 41. Specific examples include acetone, methyl ethyl ketone, toluene, and xylene. Specific examples of the dry etching process include UV / ozone and oxygen reactive etching. By performing the dry etching process after the solvent cleaning, the resist film pattern 41 and the photoreactive adhesive layer 30 can be removed in a short time, and the conductive film of the metal film pattern 21 can be formed.

  According to the first embodiment, the aspect ratio (wiring thickness / wiring width) of the obtained metal film pattern 21 increases as the reduction ratio of the equal-size metal film pattern 22 increases. Moreover, it becomes possible to raise the fineness with respect to the mold to be used. According to the first embodiment, it is only necessary to prepare a mold having a size larger than the size of a desired metal film pattern, so that the number of mold manufacturing options can be increased. For example, high productivity and low cost can be realized at the same time by applying a laser drawing method in pattern formation on the order of several hundreds of nm, which could not be applied when forming a metal film pattern with the same magnification.

As the chemical solution (etchant) used in the wet etching process for forming the metal film pattern 21, a known material can be used without limitation. It can be performed using a wet etching solution used in a conventional subtractive method. The type of wet etching solution can be selected according to the type of metal. For example, when the metal is gold or silver, an aqueous solution containing iodine / potassium iodide is preferably used. When the metal is copper, an aqueous solution containing ferric chloride (FeCl ₃ ), cupric chloride (CuCl ₂ ), Cu (NH ₃ ) ₄ Cl ₂ is preferably used. When the metal is chromium, nitric acid is mainly used. The etching solution contained in is preferably used.

  In addition, in the range which does not deviate from the meaning of this invention, processes other than the said step may be included. For example, after step 5 described above, a protective film, an insulating film, an interlayer insulating film, a semiconductor layer, or the like may be laminated on the upper layer of the metal film pattern 21 as necessary. As the protective film, a known material such as SiN or polyimide film can be used without limitation. In addition, the substrate 1 with a metal film pattern according to the first embodiment may be formed by laminating the same type or different types of substrates 1 with a metal film pattern, an optical film, or the like. Further, the metal film pattern 21 may be formed on both surfaces of the substrate 10.

  Conventionally, when manufacturing a metal film pattern, a pattern having substantially the same size as the concave / convex pattern of the mold 50 has been transferred. The main reason is that when the side etching is performed in the wet etching process, the resist film swells and a good pattern cannot be obtained. Another reason is that the wet etching chemical enters the interface between the metal film pattern and the resist film, and the resist film is peeled off, resulting in pattern defects and disconnection.

  As a result of extensive studies by the present inventors, a resist film is surprisingly obtained by interposing a photoreactive adhesive layer between a metal film and a resist film and using a hydrophobic polymer as the resist film. It was found that a high-quality metal film pattern can be obtained even if side etching is performed so as to reduce the pattern size. This is because the photoreactive compound layer 30 can firmly bond the metal film 20 and the resist film 40 to prevent disconnection or pattern failure. Further, by using a hydrophobic polymer as the main component of the resist film 40, it is possible to prevent the chemical solution from entering the resist film. As a result, it is possible to remarkably improve the resist film 40 being peeled off during the side etching in Step 5 to cause a disconnection or a pattern defect. That is, according to the first embodiment, it is possible to provide a method for manufacturing a substrate with a metal film pattern that can be finely processed as compared with the concave / convex pattern of the mold while maintaining a good pattern shape. Moreover, it is possible to easily adjust the pattern width and aspect ratio (wiring thickness / wiring width) from a single mold by simply controlling the wet etching process (wet etching time, chemical type, process conditions, etc.). A substrate with a metal film pattern of a size is obtained. For this reason, it is excellent in productivity and cost. Further, the resistance value of the metal film pattern can be easily adjusted by one mold. Furthermore, when a transparent material is used as the substrate, the permeability can be easily adjusted by adjusting the width of the metal film pattern.

  In mold manufacturing by electron beam drawing, as described above, for example, since it takes about one week to produce a circular mold of 2 inches size, it is particularly unsuitable for manufacturing a large mold. There was a problem. On the other hand, according to the method according to the first embodiment, since a fine metal film pattern on the order of 100 nm can be realized by a mold produced by a highly productive laser drawing method, it is easy to produce a mold in a large area. Has an excellent effect. Although the advantages of the laser drawing method have been described, the mold manufacturing method is not particularly limited, and the present invention is also suitable for a mold produced by another method such as an electron beam drawing method. Applicable to. In addition, the first embodiment is excellent in that a metal film pattern up to a submicron size smaller than the concave size of the micrometer-size concavo-convex pattern of the mold can be formed, but the scale of the metal film pattern is It is not particularly limited, and can be applied to a wide range of sizes.

  Further, in the conventional method of applying metal paste by screen printing or ink jet printing to produce metal wiring, the lower limit of the metal line width is about 10 μm, whereas according to the thermal nanoimprint lithography method according to the first embodiment, Also, it has an excellent effect that a metal film pattern of the order of several hundred nm can be obtained even by a laser drawing method.

  According to the manufacturing method according to the first embodiment, since fine metal wiring can be formed on a substrate with high accuracy, for example, a large number of fine metal film patterns having a line width of 0.01 μm to 10 μm can be arranged. It is. The substrate having these metal film patterns can contribute to downsizing of the device by being used for a circuit configuration of the device or the like. Furthermore, it can be applied as a component such as a wiring, a photomask, and a polarizing plate according to the spacing and shape of the line and space.

[Second Embodiment]
Next, an example of a mold manufacturing method according to the second embodiment will be described. FIG. 4 shows a schematic cross-sectional view of a mold manufactured by the mold manufacturing method according to the second embodiment. The mold 60 is obtained by excavating the base 10 using the metal film pattern 21 of the base 1 with the metal film pattern according to the first embodiment as a hard mask. FIG. 5 is a flowchart of a mold manufacturing method according to the second embodiment, and FIGS. 6A and 6B are sectional views of the mold manufacturing process according to the second embodiment.

  The mold manufacturing method according to the second embodiment includes at least step 1 to step 8 as shown in FIG. Of these, Step 1 to Step 5 are processes common to the first embodiment. Therefore, step 6 to step 8 will be described in detail below.

  In step 6, first, the resist film pattern 41 is removed (FIG. 6A). As the removal method, known methods including the method described in the first embodiment can be used without limitation. Next, in step 7, excavation processing is performed using the metal film pattern 21 as a hard mask. The excavation process is not particularly limited, but dry etching is preferable. Among them, reactive ion etching (RIE), ion milling, and the like are preferable.

  The depth of the concave portion of the base 10 can be controlled by controlling the excavation processing time. That is, the thickness of the metal film pattern 21 can be set, or a recess that is deeper or shallower than the thickness of the metal film pattern 21 can be formed. Further, a through pattern such as a through hole may be formed in the base 10.

  In step 8, the metal film pattern 21 is removed. The removal of the metal film pattern 21 can be used without particular limitation as long as it is resistant to the substrate 10 and can remove the metal film pattern 21, but there is a method of dissolving and removing the metal by wet etching. preferable. As the wet etching solution, for example, an acidic aqueous solution containing nitric acid can be used. Thereby, a concavo-convex structure is formed on the surface of the substrate 10 or a through structure is formed in the substrate 10. When the obtained mold is a mold for nanoimprinting, preferable materials for the substrate 10 include silicon oxide, quartz, glass, silicon, silicon carbide, glassy carbon, and the like.

  Through these steps, a mold as shown in FIG. 4 can be obtained. According to the second embodiment, by using the mold 50 (see FIGS. 3C and 3D), it is possible to obtain the mold 60 having a convex pattern smaller than the concave size of the concave and convex pattern on the surface of the mold 50. The mold 60 can be suitably used as a mold when, for example, it is desired to form a channel or a concave pattern such as a microchannel array, a DNA chip, or a MEMS. Moreover, it can apply suitably as a mold for nanoimprint.

  According to the mold manufacturing method according to the second embodiment, by controlling the wet etching processing conditions (wet etching time, chemical type, process conditions, etc.) in step 5 from one mold, a plurality of pattern sizes can be obtained. Different molds can be easily produced. The mold manufacturing method according to the second embodiment has an excellent effect that a mold having a convex pattern finer than the concave size of the mold 50 can be easily obtained. The obtained mold can be suitably applied, for example, as a mold for nanoimprint technology. Further, since a fine convex pattern can be easily obtained, it can be suitably applied to a mold for a purpose of forming a flow path or a concave pattern such as a microchannel array or a DNA chip. For example, a plurality of microchannel arrays having different channel widths can be produced from one mold.

  In addition, according to the manufacturing method of the second embodiment, instead of the electron beam drawing method, which is difficult to produce a large-area mold, from a mold produced by a laser drawing method that is highly productive and advantageous for increasing the area. And, it has an excellent merit that a mold having a finer size can be easily manufactured than this mold.

[Third Embodiment]
Next, an example of a mold manufacturing method different from the mold manufacturing method according to the second embodiment will be described. FIG. 8 is a schematic cross-sectional view of a mold manufactured by the mold manufacturing method according to the third embodiment. The mold 70 is manufactured using the mold 60 obtained by the mold manufacturing method according to the second embodiment as a mold. That is, the mold 70 is manufactured by using the mold 60 manufactured through steps 1 to 8 of the second embodiment as a mold. The mold 70 can be made of a resin material such as PMMA or cycloolefin, for example. For example, the mold 70 can be suitably used as a mold by an optical nanoimprint lithography method that does not require a heat treatment step or that can reduce the temperature of the heat treatment step.

  The mold 70 can be obtained, for example, by coating a thermoplastic resin such as PMMA or a photocurable resin on a substrate and transferring the uneven pattern of the mold 60 onto the mold 70. Further, as in the first embodiment, a metal film is formed on the substrate, and the resist film pattern according to the first embodiment is formed on the mold 60 from the mold 60 to obtain a substrate with the same magnification-metal film pattern. Alternatively, the substrate with a reduced metal film pattern according to the first embodiment may be obtained and used as the mold 70. Furthermore, it is good also as a mold 70 from these base | substrates with a metal film pattern through an excavation process like 2nd Embodiment.

  According to the mold manufacturing method according to the third embodiment, by controlling the wet etching processing conditions (wet etching time, chemical type, process conditions, etc.) in Step 5 from one mold, a plurality of pattern sizes can be obtained. Different molds 70 can be made. In addition, according to the method for manufacturing a mold according to the third embodiment, the mold 70 having a concave pattern finer than the concave size of the concave / convex pattern formed on the surface of the mold 50 can be easily obtained. There is. Therefore, for example, a new mold is manufactured by the manufacturing method of the second embodiment using a large mold manufactured by using a laser drawing method advantageous for manufacturing a large-area mold. It is possible to easily manufacture a mold with a fine pattern that could not be produced without using the method with high productivity.

  In the third embodiment, the method of manufacturing the final mold from a mold prepared in advance through one intermediate mold manufacturing process has been described, but the number of intermediate molds is arbitrary. By combining the manufacturing method of the substrate with a metal film pattern of the first embodiment and the manufacturing method of the mold of the second embodiment, a miniaturized mold can be easily manufactured.

[Examples] Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these examples.

  The following three samples were produced as molds. Specifically, by an electron beam lithography method using a positive electron beam resist ZEP520A (manufactured by Nippon Zeon Co., Ltd.), a silicon having an outer dimension of 20 mm square has a line and space of 1 μm (1: 1) and a depth of 250 nm. A mold was produced. The obtained mold was immersed in Optool DSX (manufactured by Daikin Industries, Ltd., HD-1101Z) for 1 minute, dried with a nitrogen flow and allowed to stand at room temperature for 1 day, and then rinsed with HD-ZV (manufactured by Daikin Industries, Ltd.). Then, a release layer was formed on the surface by drying with a nitrogen flow. This mold is referred to as mold A.

  A mold B was produced by the same structure and method as the mold A except that the line & space was 0.5 μm (1: 1). Further, a line width is formed in a 5 mm square area at the center of a 20 mm square quartz plate by a laser drawing method and a reactive dry etching method using a positive photoresist OFPR 800 LD (manufactured by Tokyo Ohka Kogyo Co., Ltd.). A lattice-shaped mold with 2 μm / cycle of 10 μm was produced. The obtained mold formed a release layer in the same manner as Mold A. This mold is referred to as mold C.

<Example 1>
On a silicon substrate having a thickness of 0.5 mm, chromium having a thickness of 20 nm and gold having a thickness of 25 nm were formed in this order by a sputtering method. And just before forming the photoreactive adhesive layer which will be described later, the above-mentioned substrate was subjected to UV / ozone treatment (PL16-116, manufactured by Sen Special Light Company) for 15 minutes. Thereby, a clean gold surface having a static contact angle of less than 5 ° of water in which organic substances attached to the surface of the metal film were decomposed oxidatively was formed. This is referred to as a metal film-coated substrate. In Example 1, silicon and chromium function as a substrate.

  Subsequently, a photoreactive adhesive layer was formed on the substrate with the metal film. Specifically, 10.0 mg of 4- (10-mercaptodecyloxy) benzophenone was dissolved in 100 mL of toluene to prepare an adhesive layer forming solution. Subsequently, the above-mentioned substrate with a metal film was immersed in this adhesive layer forming solution at room temperature for 1 hour. Thereafter, the substrate with the metal film was taken out and washed with clean toluene to obtain a substrate with a photoreactive adhesive layer. Formation of the photoreactive adhesive layer was confirmed by the static contact angle of water being 82 °.

  Subsequently, a toluene solution of 5% by mass of polystyrene (manufactured by Sigma-Aldrich, weight average molecular weight = 35,000 g / mol, glass transition temperature = 93 ° C.) was prepared, and was spun on the substrate at 3000 rpm for 30 seconds. The resist film which is a 250-nm-thick thermoplastic resin layer was applied.

Thereafter, ultraviolet irradiation was performed from the resist film side. For UV irradiation, Supercure 202S (manufactured by Mitsunaga Electric Co., Ltd.) was used, and irradiation intensity (exposure amount) was set to ² J / cm ² by irradiating with an irradiation intensity of 13 mW / cm ² for 150 seconds at a detection wavelength of 254 nm. . After the exposure, the substrate was annealed at 180 ° C. for 1 minute. Through the above steps, a substrate with a resist film was obtained.

Next, thermal nanoimprint molding was performed on the substrate with the resist film using the mold A, and the uneven pattern was transferred to the resist film. NM-400 (manufactured by Myeongchang Kiko Co., Ltd.) was used for the thermal nanoimprint apparatus. The heating process (pressing force, mold temperature, time) by the mold was performed under the five-stage conditions shown in Table 1.

  Thereafter, the remaining film was removed by UV / ozone treatment for 60 minutes using a UV / ozone cleaner (Sen special light source PL16-116), so that the metal film under the concave portion of the resist film was exposed. The obtained concavo-convex pattern was observed with an electron microscope, and it was confirmed that the concavo-convex pattern was formed on a resist film made of polystyrene having a line and space of 1 μm (1: 1). FIG. 8A shows an SEM image of the obtained resist film pattern.

  Next, wet etching was performed using AURAM 302 (manufactured by Kanto Chemical Co., Inc.) as a wet etching chemical for gold. Then, it was confirmed that a metal film pattern substantially coincident with 1 μm, which is the width of the concavo-convex pattern, was obtained in about 30 s of wet etching time. The SEM image at this time is shown in FIG. 8B. Next, a new sample is prepared, and the substrate with a metal film pattern according to Example 1 is obtained by performing a wet etching process of 60 s corresponding to twice the wet etching time 30 s to obtain the same size-metal film pattern. Obtained. The SEM image at this time is shown in FIG. 8C.

  <Example 2> The metal film pattern according to Example 2, except that the wet etching time was set to 120 s, which is four times the wet etching time for obtaining the same-size metal film pattern. A coated substrate was obtained. The SEM image at this time is shown in FIG. 8D.

  <Example 3> The metal film pattern according to Example 3 except that the wet etching time was set to 180 s, which is six times the wet etching time for obtaining a metal film pattern at the same magnification, with the same conditions as in Example 1 above. A coated substrate was obtained. The SEM image at this time is shown in FIG. 8E.

  <Example 4> A substrate with a metal film pattern was obtained in the same manner as in Example 1 except that the mold B was used. FIG. 9A shows an SEM image of a resist film made of polystyrene. Further, FIG. 9B shows an SEM image of the same-size metal film pattern formed using this resist film. And in the new sample, the substrate with a metal film pattern according to Example 4 was obtained by performing the wet etching process for 60 seconds, which is twice the wet etching time for obtaining the same-size metal film pattern. The SEM image at this time is shown in FIG. 9C.

  <Example 5> The metal film pattern according to Example 5 except that the wet etching time was set to 120 s, which is four times the wet etching time for obtaining the same-size metal film pattern. A coated substrate was obtained. The SEM image at this time is shown in FIG. 9D.

  <Example 6> The metal film pattern according to Example 6, except that the wet etching time was 180 s, which is six times the wet etching time for obtaining a metal film pattern. A coated substrate was obtained. The SEM image at this time is shown in FIG. 9E.

Table 2 shows the values obtained by laterally extending the line width from the SEM images and the line width roughness calculated from these values for each of the bases with metal film patterns, resist film patterns, and same-size metal film patterns according to Examples 1 to 6. Shown in In addition, line width shows the average value when 20 places are measured at intervals of 0.4 mm. The line width roughness is a standard deviation of the line width.

  <Example 7> A substrate with a metal film pattern was obtained in the same manner as in Example 1 except that polymethyl methacrylate (PMMA) was used instead of polystyrene as the hydrophobic polymer. Specifically, the same operation as in Example 1 was performed using a toluene solution of 5% by mass of polymethyl methacrylate (manufactured by Sigma-Aldrich, weight average molecular weight = 20,000, Tg = 110 ° C.), and the film thickness was 250 nm. A substrate with a resist film having a PMMA layer was obtained. Then, in the same manner as in Example 1, a resist film pattern was formed by heat molding, and the remaining film was removed. The obtained concavo-convex pattern was observed with an electron microscope, and it was confirmed that a concavo-convex pattern having a line and space of 1 μm (1: 1) was formed on the resist film. FIG. 10A shows an SEM image of the obtained resist film pattern.

  Subsequently, the gold thin film was wet-etched in the same manner as in Example 1. Then, it was confirmed that a metal film pattern substantially coincident with 1 μm, which is the width of the concavo-convex pattern, was obtained in about 30 s of wet etching time. The SEM image at this time is shown in FIG. 10B. Next, a substrate having a metal film pattern according to Example 7 is prepared by preparing a new sample and performing wet etching processing in 60 s corresponding to twice the wet etching time of 30 s to obtain the same size-metal film pattern. Got. The SEM image at this time is shown in FIG. 10C.

  <Example 8> The metal film pattern according to Example 8 except that the wet etching time was set to 120 s, which is four times the wet etching time for obtaining the same-size-metal film pattern. A coated substrate was obtained. The SEM image at this time is shown in FIG. 10D.

  <Example 9> A substrate with a metal film pattern was obtained in the same manner as in Example 7 except that the mold B was used. FIG. 11A shows an SEM image of a resist film made of polystyrene. In addition, FIG. 11B shows an SEM image of the metal film pattern having the same magnification with a wet etching time of 30 s. Further, in a new sample, wet etching treatment was performed for 60 s, which is twice as long as the wet etching time for obtaining the same-size metal film pattern, to obtain a substrate with a metal film pattern according to Example 9. The SEM image at this time is shown in FIG. 11C.

  <Example 10> The wet etching time is the same as that of Example 9 except that the wet etching time is 120 s, which is four times the wet etching time for obtaining a metal film pattern. With the metal film pattern according to Example 10 A substrate was obtained. The SEM image at this time is shown in FIG. 11D.

Table 2 shows values obtained by laterally extending the line width from the SEM images and the line width roughness calculated from these values for each of the bases with metal film patterns, resist film patterns, and equal-magnification metal film patterns according to Examples 7 to 10. Shown in In addition, line width shows the average value when 20 places are measured at intervals of 0.4 mm. The line width roughness is a standard deviation of the line width.

  <Example 11> Except as described below, a metal film-coated substrate was produced. As the substrate, a glass having a thickness of 1.0 mm was used, and as the metal film pattern, a laminated film of chromium and gold was used. A substrate with a photoreactive adhesive layer was produced in the same manner as in Example 1. Formation of the photoreactive adhesive layer was confirmed by measuring the static contact angle of water and having a contact angle of 82 °.

  Subsequently, a toluene solution of 5% by mass of polystyrene (manufactured by Polymer Source, Inc., weight average molecular weight = 11,000 g / mol, glass transition temperature = 93 ° C.) was prepared, and was rotated on the substrate at 3000 rpm for 30 seconds. Spin coating was performed under the conditions to form a resist film having a thickness of 150 nm.

Then, the base | substrate with a resist film was obtained by implementing ultraviolet irradiation from the upper direction of a resist film on the conditions similar to Example 1. FIG. Next, thermal nanoimprint molding was performed on the substrate with the resist film using the mold C, and the uneven pattern was transferred to the resist film. NM-400 (manufactured by Myeongchang Kiko Co., Ltd.) was used for the thermal nanoimprint apparatus. The heating process (pressing force, mold temperature, time) by the mold was performed under the five-stage conditions shown in Table 4.

  Thereafter, the remaining film was removed by UV / ozone treatment for 60 minutes using a UV / ozone cleaner (Sen special light source PL16-116), so that the metal film under the concave portion of the resist film was exposed. The obtained concavo-convex pattern was observed with an electron microscope, and it was confirmed that the concavo-convex pattern was formed on a resist film made of 150 nm polystyrene.

  Subsequently, after performing the wet etching process with respect to gold | metal | money by the method similar to Example 1, the wet etching process with respect to chromium was performed using the etching chemical | medical solution for chrome (nitric acid type) (made by Hayashi Junyaku Kogyo Co., Ltd.). Then, it was confirmed that a metal film pattern substantially corresponding to 2 μm, which is the concave pattern width of the mold C, was obtained in about 15 s of wet etching time for gold. The optical microscope image at this time is shown in FIG. 12A. Next, a new sample was prepared, and the time during which the pattern width of the convex portion of the metal film pattern was ½ of the concave pattern width of the mold C was determined. As a result, it was found that a wet etching process of 120 s corresponding to 8 times the wet etching time of 15 s for obtaining a metal film pattern of approximately the same magnification was necessary. The substrate with the metal film pattern according to Example 11 was obtained by performing the wet etching process for gold for 120 s and the wet etching process for chromium for 5 s through the above steps. A reflection type optical microscope image at this time is shown in FIG. 12B.

  <Example 12> According to Example 12, except that the wet etching time for gold is 240 s, which is 16 times the wet etching time for obtaining a metal film pattern of the same magnification, under the same conditions as in Example 11 above. A substrate with a metal film pattern was obtained. A reflection type optical microscope image at this time is shown in FIG. 12C.

  <Example 13> The base | substrate with a metal film pattern which concerns on Example 13 was obtained by the method similar to Example 11 except having used the silver formed into a film by electroless plating as a metal film. Specifically, using a glass having a thickness of 1.0 mm, a silver film having a thickness of 120 nm was formed by electroless plating, and exposed to the atmosphere to obtain a metal film having a metal oxide surface. And the development time when the metal film pattern substantially corresponding to 2 μm which is the concave pattern width of the mold C was obtained was obtained. As a result, it was confirmed that a pattern was obtained in 2 seconds. A reflection type optical microscope image at this time is shown in FIG. 13A. Next, a new sample was prepared, and the time during which the pattern width of the convex portion of the metal film pattern was ½ of the concave pattern width of the mold C was determined. As a result, it was found that a wet etching process of 4 s corresponding to twice the wet etching time 2 s for obtaining a metal film pattern of about the same magnification was necessary. A substrate with a metal film pattern according to Example 13 was obtained by performing wet etching treatment for 4 s through the above steps. A reflection type optical microscope image at this time is shown in FIG. 13B.

  The transmittance and surface resistivity of the obtained sample were measured, and the characteristics as a transparent metal film were evaluated. The surface resistivity was measured using Loresta-EP and probe PSP manufactured by Mitsubishi Chemical Corporation. The obtained results are shown in FIGS. 13A and 13B.

  FIG. 14A shows light transmission spectra of the base with a metal film pattern according to Example 13 and the base with the same-size metal film pattern manufactured in Example 13. FIG. When the average transmittance at a wavelength of 400 to 800 nm of the substrate with the same magnification-metal film pattern (convex pattern width 2 μm) was obtained, it was 42%, and the average transmittance with respect to the substrate (when the transmittance of the substrate was normalized as 100%) The average transmittance (hereinafter the same) was 46%. Moreover, when the average transmittance | permeability in wavelength 400-800nm of the base | substrate with a metal film pattern (convex pattern width 1 micrometer) which concerns on Example 13 was calculated | required, it was 59% and the average transmittance | permeability with respect to a base | substrate was 64%.

  FIG. 14B shows the light transmission spectra of the base with a metal film pattern according to Example 11, the base with the same-size metal film pattern prepared in Example 11, and the base with a metal film pattern according to Example 12. The average transmittance of the substrate with the same magnification-metal film pattern (convex pattern width 2 μm) at a wavelength of 400 to 800 nm was 44%, and the average transmittance with respect to the substrate was 47%. Moreover, the average transmittance | permeability in wavelength 400-800nm of the base | substrate with a metal film pattern (convex pattern width 1 micrometer) which concerns on Example 11 was 61%, and the average transmittance | permeability with respect to a base | substrate was 65%. Moreover, the average transmittance | permeability in wavelength 400-800nm of the base | substrate with a metal film pattern (convex pattern width 0.8 micrometer) which concerns on Example 12 was 66%, and the average transmittance | permeability with respect to a base | substrate was 69%.

  On the other hand, when the theoretical transmittance calculated from the aperture ratio of the lattice pattern is obtained for the substrate having the same magnification-metal film pattern manufactured in Examples 11 and 13, the average transmittance for the substrate is 64%. On the other hand, the measured values were 47% and 46%, respectively. Further, when the theoretical transmittance calculated from the aperture ratio of the lattice pattern is obtained for the substrate with the metal film pattern according to Examples 11 and 13, the measured value is 81% with respect to the substrate. They were 65% and 64%, respectively. Moreover, when the theoretical transmittance | permeability calculated from the aperture ratio of a grating | lattice pattern was calculated | required with respect to the base | substrate with a metal film pattern which concerns on Example 12, it became 85%, and the measured value became 69%. It has been reported that the transmittance with respect to the aperture ratio of the metal film pattern does not agree with the theoretical value, which is smaller than the calculated value due to the influence of surface plasmon resonance. In Examples 11, 12, and 13 as well, the reason why the measured value was lower than the theoretical value is presumed to be influenced by resonance derived from the metal structure.

  In Example 11, the surface low efficiency before the pattern formation in which the gold film was formed on the glass was 2Ω / □. On the other hand, the surface resistivity of the substrate having the same magnification-metal film pattern produced in Example 11 is 13 Ω / □, and the surface low efficiency of the substrate with the metal film pattern according to Example 11 is 22 Ω / □. The surface low efficiency of the substrate with the metal film pattern was 45Ω / □. From this, it can be seen that high conductivity is maintained even after patterning. Similarly, in Example 13, the surface low efficiency in a state where a silver film was formed on glass (before pattern formation) was 0.5Ω / □. On the other hand, the surface low efficiency of the substrate with the same magnification-metal film pattern (line width 2 μm) described in Example 13 is 4Ω / □, and the surface low efficiency of the substrate with metal film pattern (line width 1 μm) according to Example 13 is low. The efficiency was 23Ω / □. From this, it can be seen that high conductivity is maintained even after patterning.

  It can be seen from Example 13 that visible light transmission can be controlled by controlling the wet etching process time using one mold. Further, according to Example 11, Example 12, and Example 13, it is understood that the conductivity can be adjusted by controlling the wet etching processing time using one mold. Development as a transparent conductive film can be expected by improving transmittance and adjusting conductivity by optimizing the structure.

  The method for manufacturing a substrate with a metal film pattern according to the first embodiment can copy a large amount of patterns on the order of nanometers. Therefore, the method is not limited to so-called lithography. MEMS, micro optical elements, patterned magnetic memory elements, etc. It can be expected to spread to various manufacturing processes. Moreover, since it is excellent in electromagnetic wave shielding property, a highly accurate metal wiring can be formed, and it is easy to manufacture, it can be used in a wide field. For example, it can be used for electromagnetic wave shielding materials, antistatic films, wire grids, various antennas and the like that can be used for flat panel displays such as LCDs, solar cells, various touch panels, and the like. Moreover, application development as a transparent conductive film substrate can be expected by using a transparent material as the substrate.

DESCRIPTION OF SYMBOLS 10 Base | substrate 20 Metal film 21 Metal film pattern 22 1 time-metal film pattern 30 Photoreactive adhesive layer 40 Resist film 41 Resist film pattern 50, 60, 70 Mold

Claims (4)

Forming a metal film on a substrate made of a transparent material ;
A photoreactive adhesive layer and a resist film composed mainly of a hydrophobic polymer made of a thermoplastic resin are formed in this order on the metal film, and the photoreactive adhesive layer is irradiated with actinic rays. Adhering the adhesive layer and the resist film;
Forming a resist film pattern by transferring a concavo-convex pattern formed on the surface of the mold to the resist film;
A step of performing a residue treatment so that the resist film is removed in the recesses of the concavo-convex pattern formed in the resist film pattern;
Using the resist film pattern, wet etching the exposed metal film to form a metal film pattern,
The step of forming the metal film pattern includes a recess size of the concavo-convex pattern of the mold so that the metal film pattern has a reduced size in a plan view than a recess size of the concavo-convex pattern formed on the surface of the mold. Performing a wet nanoimprint lithography method including a step of performing a side etching of the metal film pattern by extending the wet etching processing time longer than obtaining a substantially equal metal film pattern ,
A method for producing a substrate with a metal film pattern, which is used as a transparent conductive substrate by increasing the average transmittance of the substrate on which the metal film pattern at a wavelength of 400 to 800 nm is formed by the side etching .   2. The method of manufacturing a substrate with a metal film pattern according to claim 1, wherein a reduction ratio of the metal film pattern is 90% or less of a recess size of the uneven pattern formed on the surface of the mold.   3. The method for manufacturing a substrate with a metal film pattern according to claim 1, wherein a reduction ratio of the metal film pattern is 70% or less of a recess size of the uneven pattern of the mold.   The method for producing a substrate with a metal film pattern according to any one of claims 1 to 3, wherein the resist film is a polystyrene-based, polyvinyltoluene-based, or cyclic polyolefin-based polymer.