JP2012246507A - Method for manufacturing thin film metal component, and optical component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for easily manufacturing a fine metal thin film component in a sub-millimeter order to a nanometer level, in particular, a metal thin film component whose shape is in a coil state.SOLUTION: The method for manufacturing a thin film metal component is configured to apply a photolithographic process to a metal thin film 2 formed by depositing a single or a plurality of materials on a substrate 1 to form a desired pattern shape, and then, apply a high voltage to a metal thin film pattern 5 to peel the metal thin film pattern 5 from the substrate 1. The method for manufacturing a thin film metal component 7 is characterized in that in the thin film metal component, a scale has the degree of a sub-millimeter order or smaller and a shape is in a coil state or like a cut wire.

Description

  The present invention relates to a method of manufacturing a thin film metal component, and more particularly, a method of manufacturing a thin film metal component in which a metal thin film is formed in a desired pattern on a transparent substrate and then the metal pattern is peeled from the transparent substrate. About.

  Various applications are expected for metal parts having a three-dimensional form. Examples include coils, springs, metal meshes, and the like used in micromachines (MEMS, Micro Electro Mechanical Systems) and microsensors. As a special one, there is a metamaterial which is a synthetic material having a negative refractive index and laid with submillimeter order cut wires made of silver, copper, aluminum or the like. Metamaterials have the property of extraordinarily refracting electromagnetic waves having the same diameter as the diameter of cut wires laid in the metamaterial (Non-Patent Document 1).

  An isolated metal part including a bending process having a ring shape as described above has generally been manufactured using machining or sheet metal processing using a mold if it has a size of about a centimeter. In machining using a mold, an expensive mold is necessary, and a shape that can be formed is usually one kind, and the size is limited to about millimeters.

  If it is a flat metal part, it is manufactured by processing the metal thin film formed on the substrate into a fine pattern using photolithography technology and cutting the whole board, but it is an isolated metal part without a support substrate Were rarely produced by this method.

  On the other hand, several techniques for peeling a metal thin film from a substrate are known. A typical technique is to elute a metal thin film on a glass substrate, for example, metal chromium, by immersing and energizing a glass substrate on which a metal thin film is formed in an electrolytic solution (see, for example, Patent Document 1). ). This is different from peeling the metal while maintaining its outer shape, and usually recovers the metal portion that is discarded by changing its shape and reusing it.

  As another metal thin film peeling method, a technique is disclosed in which a metal thin film adhered on an insulating resin is placed between electrodes and discharged between the electrodes to discharge the metal thin film. (Patent Document 2). This is a technical idea that the resin side rather than the metal component is recycled and reused, unlike the above-described case where the metal component is dissolved to recover the metal component. According to this method, it is described that the metal thin film can be peeled even when the adhesion strength of the metal thin film to the resin is strong or the metal thin film is thick, and the metal type is not limited.

JP 2005-48275 A Japanese Patent No. 4523789 JP 2006-038728 A

T.A. W. Ebesen, et al. , Nature, 391, 667 (1998).

Usually, in order to process a metal material into a desired shape and form, machining using a mold or sheet metal processing is used. In machining using a mold, an expensive mold is required, and there is usually only one shape that can be formed. Further, since sheet metal processing is usually manual processing, there is a problem that a large amount of productivity is poor, and the processing is limited to processing of articles having a certain size or more.
On the other hand, the processing of fine metal thin film parts of sub-millimeter order to nano level is often formed on a support, and it is difficult to take out metal parts in an isolated form. If the support is a thin metal, it can be taken out by etching the difference in solubility or the support, but it is not easy if it is an insulating resin.
Accordingly, an object of the present invention is to provide a method capable of easily producing a fine metal thin film component of sub-millimeter order to a nano level, particularly a metal thin film component having a coil shape.

  In order to achieve the above-mentioned object, the invention according to claim 1 is characterized in that a metal thin film formed by laminating a single material or a plurality of materials on a substrate is formed into a desired pattern shape by applying a photolithography method. A method of manufacturing a thin film metal component is characterized in that a high voltage is applied to the metal thin film pattern to peel the metal thin film pattern from the substrate.

  The invention according to claim 2 is the method of manufacturing a thin film metal part according to claim 1, wherein the scale of the thin film metal part is 1 nm or more and less than 1 mm.

  The invention described in claim 3 is the method of manufacturing a thin film metal part according to claim 1 or 2, wherein the thin film metal part is a coil.

  The invention according to claim 4 is the method for producing a thin film metal part according to claim 1 or 2, wherein the metal part is a cut wire.

  The invention according to claim 5 is the method for producing a thin film metal part according to any one of claims 1 to 4, wherein the metal part has magnetism.

  The invention according to claim 6 is an optical component characterized in that the cut wire according to claim 4 is dispersed in an insulating resin.

The invention of claim 1 is a method of manufacturing a thin film metal part in which a fine metal pattern formed on an insulating substrate by a photolithography method is peeled off from the substrate by using a discharge effect by applying a high voltage.
In particular, since the metal pattern once formed on the substrate and then peeled off from the substrate has a difference in stress between the front and back sides, it is generally curled naturally so that the metal surface that is in contact with the substrate is inward. A metal part having a three-dimensional shape is obtained.
Further, if the original metal pattern is linear or strip-like, it becomes a linear or plate-like thin-film metal part that is bent near a perfect circle.
By applying photolithography technology, a large number of metal patterns having various shapes can be created and processed simultaneously. In addition, the effect of adjusting the degree of curling and adjusting the physical properties of the metal part can be achieved by making the metal part multi-layered.

  The invention of claim 2 limits the size of a metal part from a sub-millimeter order to a nano-level range that can be handled by a photolithographic method because a solid metal part having a size of about centimeter can be produced by a conventional method. . This manufacturing method can easily manufacture thin-film metal parts in this size range.

The inventions of claims 3 and 4 specify the form of the thin-film metal part to which the present manufacturing method is particularly preferably applied. It is a coil and a cut wire in which a linear or strip-shaped metal pattern peeled off from a substrate is directed spontaneously. In particular, it can be applied as a spring whose strength can be adjusted by appropriately adjusting the metal material and the length of the wire or band. Various applications such as taking out the rotational movement of the shaft by winding this spring can be expected.

According to the fifth aspect of the present invention, when a magnetic material is selected for the metal, there is an effect that a part obtained by bending can be applied as a part of a nano-sized coil or a generator.
In addition, after forming a film on the surface of the part, especially by the sol-gel method, the part can be placed at a specific position by controlling the movement with a magnet, and the characteristics of the substance can be exhibited. It is.
In addition, depending on the shape of the pattern formed on the thin film, when not only the coil and the spring but also the mesh pattern is processed, a nano-size filtration filter can be formed. This filter can be expected to be applied to removal of impurities at a molecular level in a minute amount of liquid.

  The inventions of claims 6 and 4 relate to a cut wire having a cut in a ring and a method for arranging the cut wire. A cut wire is a unique optical member that has a negative refractive index (negative dielectric constant and magnetic permeability), but when it is laid on a support substrate, it is only placed so that the ring surface is parallel to the substrate and optical. Is anisotropic. An isolated cut wire obtained by the present production method dispersed in a resin and molded into a plate shape is an optically isotropic synthetic material because the ring surface is equally oriented in various directions.

(A)-(g) It is a figure of the cross-sectional view explaining the manufacturing process of a thin film metal component. It is a reproduction of a photograph showing an example of a thin film metal part obtained by high pressure discharge peeling. It is a schematic diagram explaining the structure of a cut wire It is a perspective view which shows typically a thin film metal pattern and the external appearance shape assumed when it curls spontaneously and becomes a thin film metal component. It is a figure which illustrates the example of application of a magnetic metal ring typically.

  The photolithographic method can easily form a fine desired metal pattern of submillimeter order or less on an insulating resin substrate. Therefore, the present invention is a high-pressure discharge stripping technology, which is a technology for stripping and recovering a metal film attached to an insulating resin, for the purpose of stripping a metal pattern that has been purposely formed on an insulating substrate, not for waste collection. It is a combination of both technologies.

  Hereinafter, an outline of a method for producing a thin film metal component according to the present invention will be described with reference to the drawings.

1. Formation of Metal Thin Film Pattern A glass material such as quartz glass or soda glass was used as the substrate 1 on which the desired metal pattern 5 was formed. The metal is different as long as the desired metal target such as aluminum, gold, silver, chromium, iron, nickel, etc. can be used and metal etching can be performed on the glass substrate with a thickness of about 30 nm to 200 nm by sputtering or vacuum deposition. Metals can also be stacked (FIGS. 1A and 1B).

  Etching is used for pattern formation. However, since general-purpose wet etching involves side etching, the thickness of the metal thin film 2 must be smaller than the line width. Therefore, the thickness of the metal thin film 2 is determined depending on the desired line width. Moreover, a metal thin film can also be formed by electrolytic plating.

  Next, a photosensitive resist 3 (ZEP520, manufactured by Nippon Zeon Co., Ltd.) was applied on the chromium thin film by spin coating to a thickness of about 100 nm (FIG. 1 (c)), and then programmed to obtain a desired shape. A thin strip pattern was drawn on the resist film with an electron beam drawing apparatus. Thereafter, the photosensitive resist was developed with a predetermined developer, and unnecessary portions were removed to obtain a resist pattern (FIG. 1 (d)).

  In order to dissolve the underlying metal thin film exposed at the resist opening, the unnecessary metal thin film was removed by etching using an oxidizing chemical (cerium ammonium nitrate solution). In this manner, a large number of strip-shaped metal patterns 5 (width 15 μm, length 100 μm) serving as precursors of metal thin film components were formed in a matrix on the glass substrate 1 (FIG. 1 (e)). As for the exposure, instead of electron beam exposure, ArF excimer laser, KrF excimer laser or the like may be used for light exposure.

2. Metal thin film pattern peeling (part processing)
Although not described in detail, the discharge device is configured so that a voltage can be applied by arranging two discharge electrodes 6 facing each other at a predetermined distance, and the metal pattern 5 to be peeled is accommodated in the discharge space. If it does so, the metal pattern 5 will peel from the board | substrate 1 by electric discharge. The distance between the discharge electrodes 6 is preferably 1 mm or more and 20 mm or less, and the discharge electrode and the metal pattern should not be in contact with each other, and it is desirable to maintain a distance of 0.1 mm or more and 1.0 mm or less (FIG. 1 (f )).

  The high voltage was applied using a pulse power generator. The pulse power generator causes discharge by applying a high voltage between electrodes by a pulse discharge circuit. The pulse power is high-density energy that is concentrated in a narrow space in a short time by compressing stored energy temporally and spatially. Energy can be adjusted by voltage, number of discharges, and discharge cycle.

  In this example, a voltage of 1 kV to 2 kV was applied using a static electricity tester (MODEL: ESS-2002) manufactured by Noise Research Institute Co. It was made to peel. A plurality of adjacent metal patterns may be peeled off at the same time. As shown in the SEM (Scanning Electron Microscope) photograph in FIG. 2, the peeled thin strip-shaped metal piece was spontaneously curled into a ring-shaped thin film metal part 10 (FIG. 1 (g )). 2 has a band width of about 15 μm and an inner diameter of about 100 μm.

3. Pattern shape of metal thin film Thin film metal parts of various forms can be obtained by the above process, but the appearance of thin film metal parts and thin film metal parts that are assumed to be spontaneously deformed due to the difference in stress between the front and back A correspondence table of the shapes is shown in FIGS.

  The size of the thin-film metal part after the peeled metal piece is spontaneously deformed is about submillimeter order or less. Here, the sub-millimeter order means that the maximum passing dimension is about several hundred microns or less, and that it is necessary to use a somewhat advanced photolithography method.

The metal cut wire 11 having the outer shape shown in FIG. 3 having a negative refractive index will be described. The cut wire 11 is a ring-shaped member having a cut 12 in one place, and can be said to be a shape to which the present invention is easily applied. It is known that when the refractive index becomes negative, a refraction phenomenon that a normal positive refractive index does not show and a unique optical effect is exhibited (Non-patent Document 1). If the cut wire 11 is intended for microwaves or infrared rays having a wavelength of about micron or more, the ring is passed over a micron and is easy to process. The ring portion does not need to be a perfect circle at all, and may be a form in which both sides of the cut 12 portion are close to each other.

  The cut wire 11 that can be used at visible wavelengths is truly fine and requires sub-micron processing, but in the present invention, a ring-shaped metal piece equal to the length of the outer circumference can be formed in advance, rather than making a ring directly. In this case, since the ring shape can be obtained spontaneously, the processing is easy. However, it is necessary to adjust the length and thickness of the metal material so that both ends do not contact. Aluminum is preferable as the metal material in view of the plasma frequency in order to support the infrared wavelength region. In the visible wavelength region, silver or gold is preferable as the metal material composing the wire.

  Since the cut wire 11 is usually formed on a silicon substrate or a printed board, the cut wire 11 is laid flat. When the magnetic field penetrates the ring opening 13, the optical effect becomes efficient, but in order to penetrate, a large number of substrates with cut wires need to be arranged, and the density of the wires is not high.

  If the cut wire 11 according to the present invention is uniformly dispersed in an ultraviolet curable resin or a thermosetting resin and then cured as appropriate to form a plate shape, a synthetic optical material having a negative refractive index without anisotropy Material can be obtained.

  Another application of the metal ring 10 having magnetism is a filter that utilizes the adsorption effect of the ring. This is an effect as schematically shown in FIG. Assume that there is a solution 14 in which some medium 15 that specifically reacts with a specific metal is dispersed. When the ring 10 made of the metal and having a diameter about the size of a specific medium is dispersed in the solution 14, the medium is trapped 17 inside the ring. When the external magnetic field 18 is applied in this state, the ring can be moved in a specific direction.

  In addition, metal rings such as silver and niobium exhibiting superconductivity at low temperatures are also conceivable. Applications of magnetic traps are expected.

1. Substrate 2, metal thin film 3, photosensitive resist 4, resist pattern 5, thin film metal pattern 6, discharge electrode 7, thin film metal ring 10, ring-shaped thin film metal part 11, cut wire 12, cut 13, ring (wire ) Opening 14, solution 15, medium 16, solute 17, trapped medium 18, external magnetic field

Claims (6)

  A metal thin film formed by laminating a single material or a plurality of materials on a substrate is formed into a desired pattern shape by applying a photolithography method, and then a high voltage is applied to the metal thin film pattern to A method for producing a thin-film metal part, comprising peeling off a thin-film pattern from a substrate.   The scale of the said thin film metal component is 1 nm or more and less than 1 mm, The manufacturing method of the thin film metal component of Claim 1 characterized by the above-mentioned.   The method of manufacturing a thin film metal part according to claim 1, wherein the thin film metal part is a coil.   The method of manufacturing a thin film metal part according to claim 1, wherein the metal part is a cut wire.   The method of manufacturing a thin-film metal part according to any one of claims 1 to 4, wherein the metal part has magnetism.   5. An optical component, wherein the cut wire according to claim 4 is dispersed in an insulating resin.