Magnetic wire with micro coil and method for manufacturing the same

Abstract

To provide a micro coil element of which the size is extremely small and the magnetic conversion rate is high by effectively utilizing a semiconductor process, a magnetic wire with a micro coil and a method for manufacturing a magnetic wire with a micro coil element (a micro coil element).SOLUTION: A magnetic wire 11 with an insulation coating uses a magnetic wire as a core and an outer periphery thereof is coated with an insulative material such as glass, resin, oxide, etc., of which the film thickness is equal to or less than 2 mm. A conductive coil 12 consists of a coil main body 121 surrounding the magnetic wire with the insulation coating and coil electrodes 122 which are disposed in both ends of the coil main body. The coil electrodes are mounted in a form connected to coil ends in both ends and a size that is 5 to 10 times as large as a coil wire width is defined as a standard. An external insulation coating electrically insulates the conductive coil from the outside and further protects the conductive coil and the insulation coating per se from environmental damage.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technique for forming a microcoil directly on the surface of a magnetic wire using a semiconductor process. [Background technology]

[0002] Microcoil components are widely used in magnetic sensors, microelectromagnets, microgenerators, inductance components, etc. In all cases, their performance is greatly influenced by the number of coil turns or coil pitch (density of coil turns per unit length) and the effective permeability and volume of the magnetic wire. In the case of microcoils, since the volume of the magnetic wire is very small, in order to improve performance, it is necessary to reduce the coil pitch and increase the number of coil turns.

[0003] When a mechanically wound microcoil is made by attaching a bobbin to the surface of a magnetic wire with a diameter of 1 mm or less and mechanically winding the microcoil around it, the coil pitch is limited to 10 μm, taking into account the diameter of the enameled wire. Furthermore, considering the need for a bobbin, the magnetic wire diameter increases by approximately 100 μm to 200 μm, making it difficult to achieve micro-sizing.

[0004] A microcoil made using a semiconductor process is disclosed in Patent Document 1 (Patent No. 5747294). Currently, a coil pitch of 3 μm has been achieved, making it more promising than mechanical coils, which have a coil pitch limit of 10 μm. However, because the microcoil is formed on a substrate, the substrate must be 200 μm wide and 200 μm thick, making the overall size large. When used as a magnetic sensor, microgenerator, microvibrator, or microelectromagnet in in-vivo medical devices such as catheters and gastroscopes, the space in which they are inserted is extremely narrow, so it is desirable to omit the substrate and attach the microcoil directly to the magnetic wire. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5747294 Summary of the Invention [Problem to be solved by the invention]

[0006] To eliminate the need for a substrate for microcoils formed using semiconductor processes, it is necessary to form the microcoil directly on the surface of an insulating coated magnetic wire. The semiconductor process is a technology for printing microwiring patterns onto a flat substrate, but it is necessary to develop a new technology for printing microcoils onto the surface of a three-dimensional magnetic wire using this technology. [Means for solving the problem]

[0007] As a result of intensive research into the above technical problems, the inventors arrived at the technical idea of the present invention that a microcoil can be formed by performing rotational exposure while feeding a magnetic wire laterally. The idea is to first laminate a conductive thin film on the surface of an insulating coated magnetic wire, then apply a resist on top of that, and perform rotational exposure while feeding the wire. After that, an etching process is performed, and a protective coating is attached to the coil to form a microcoil.

[0008] The magnetic wire with microcoil is The magnetic core is made of a magnetic wire, and the magnetic core is made of a conductive coil and an outer insulating coating. The magnetic wire is insulated and has a diameter of 5 μm to 1 mm, and the conductive coil is made of a highly conductive material such as Cu, Al, or Au with a coil pitch of 2 μm to 200 μm. The outer insulating coating electrically insulates the coil from the outside and also protects the membrane from environmental damage, and has a thickness of 100 μm or less.

[0009] When using photolithography to pattern microcoil wiring on the surface of a magnetic wire with large curvature and unevenness, the curvature creates a gap between the mask and the wire resist coating at areas other than the vertices of the wire, resulting in insufficient exposure during exposure.To avoid this, the exposure time and rotational feed speed are adjusted by rotating the wire so that the exposure width remains constant.For example, in the case of a feed pitch of 5 μm, it was discovered that this can be achieved by synchronizing the rotational speed per rotation with the feed amount of 5 μm, and matching the feed time with the exposure time.

[0010] The metal film was deposited on the wire surface in a vacuum chamber while rotating using a rotating device to ensure uniform deposition on the surface. Next, a resist was applied to the metal film, and after exposure, development was performed. The rotating exposure mask on top of the insulating film had slits corresponding to the number of turns of each coil. Rotary exposure was performed using this mask, and the resist was then removed from areas other than those exposed by etching, and the metal in the areas where the resist was removed was then removed by chemical etching.

[0011] The final product, a magnetic wire with a microcoil, is wound around a bobbin for easy handling. For practical use, it can be cut to an appropriate length and handled by wiring the coil using the coil electrode as an electrode terminal.

[0012] In addition, magnetic wire with microcoils has coil electrodes attached at periodic intervals, making coil electrode wiring easier. Coil electrodes can be realized by leaving wide open spaces between coils at regular intervals and exposing coil electrodes wider than the coil wire width at the ends of both coils. This is suitable for applications such as pickup coils, electromagnetic coil magnets, and micro-generators that use coils to detect changes in the magnetization state of magnetic wire.

[0013] To prevent electrical leakage to the external environment and to avoid mechanical, thermal, and chemical damage from the external environment, an external insulating coating is attached to each of the above microcoils while rotating. The thickness of the insulating coating is 100 μm or less, preferably 30 μm to 10 μm depending on the diameter of the magnetic wire.

[0014] Regarding electrical wiring between the microcoil and external equipment, electrical wiring can be performed without significantly changing the diameter of the microcoil by joining an external lead-in wire to the electrode terminal of the open pad portion of the coil in the outer insulating coating and then performing an insulating process. [Effects of the Invention]

[0015] By utilizing semiconductor processes, it is now possible to attach a microcoil with a diameter of 10 μm and a coil pitch of approximately 5 μm directly to a magnetic wire. This extremely small microcoil with a high magnetic conversion rate is an extremely useful invention for improving the functionality of magnetic sensors, microelectromagnets, microgenerators, and inductance components used in living organisms. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view of a concept showing a magnetic wire with a microcoil. [Figure 2] FIG. 2 is a cross-sectional view of the magnetic wire with a microcoil taken along line A1-A2. [Figure 3] This is a conceptual diagram of a magnetic wire with multiple microcoils. [Figure 4] FIG. 1 is a manufacturing flow diagram of a microcoil element. DETAILED DESCRIPTION OF THE INVENTION

[0017] The magnetic wire with a microcoil of the present invention is The magnetic wire includes an insulating coating (hereinafter referred to as the magnetic wire), a conductive coil (hereinafter referred to as the coil), and an outer insulating coating. The magnetic wire has a diameter of 5 μm to 1 mm and an effective magnetic permeability of 1000 or more, and is coated on its outer periphery with an insulating material such as glass, resin, or oxide having a thickness of 2 μm or less, The coil comprises a coil body that wraps around the magnetic wire and coil electrodes at both ends of the coil body, and the coil body has a coil pitch of 2 μm to 10 μm and is made of a conductive material with excellent conductivity, such as Cu, Al, or Au, The outer insulating coating is a coating for providing electrical insulation between the coil and the outside and protecting the coil from environmental damage, and has a thickness of 100 μm or less. It is characterized by:

[0018] The magnetic wire with a microcoil is characterized by having coil electrodes at periodic intervals.

[0019] The magnetic wire with a microcoil is characterized by being made up of a large number of magnetic wires with a microcoil (microcoil elements).

[0020] The method for producing a magnetic wire with a microcoil includes the steps of: (1) A magnetic wire with an insulating coating (hereinafter referred to as magnetic wire) is placed in a deposition device. (2) While rotating the magnetic wire, a metal coating having excellent conductivity is uniformly deposited on the surface of the wire; (3) then applying a uniform resist coating onto the metal coating; (4) A wire feed device capable of rotating and feeding at a constant speed is installed in the exposure device, and the magnetic wire is rotated once while being exposed using a mask having a slit for exposing the coil body, and the feed amount at that time is the pitch amount of the coil body, and the exposure time is set to match the feed time, Next, a mask having slits for exposing the coil electrodes is used to expose the coil electrodes on both ends of the coil. (5) After exposure, development is performed, the resist is removed from areas other than the exposed areas, and then the metal from the areas where the resist has been removed is removed by chemical etching, thereby forming a coil body and a coil electrode on the insulating coating on the surface of the magnetic wire; (6) Next, an external insulating coating is applied to electrically insulate the coil, which is made up of the coil body and the coil electrodes, from the outside. It is characterized by: The microcoil element can be manufactured by cutting out individual pieces from a magnetic wire with a microcoil.

[0021] Hereinafter, a detailed description will be given with reference to FIGS. <Magnetic wire with insulating coating (magnetic wire)> The insulating coated magnetic wire 11 (21, 31) has a magnetic wire 210 as a magnetic core, and the outer periphery of the magnetic wire 210 is coated with an insulating material 21G such as glass, resin or oxide with a thickness of 2 mm or less. The diameter of the magnetic wire 210 is 5 μm to 1 mm, and preferably 100 μm to 500 μm for applications in micro-generators, micro-oscillators and electromagnets. If a coating of insulating material with a thickness of 2 mm or less is insufficient, the surface of this insulating material 21G may be additionally coated with an insulating material such as resin, and a conductive coil may be formed on that surface.

[0022] <Conductive coil (coil)> The conductive coil (coil) 12 (22, 32) is composed of a coil body 121 (22, 321) wound around an insulating coated magnetic wire 11 (21, 31) and coil electrodes 122 (322) arranged on both ends of the coil body. The conductive coil 12 (22, 32) has a coil pitch of 2 μm to 200 μm. It is made of conductive materials with excellent conductivity, such as Cu, Al, and Au. The finer the coil pitch, the better, but it varies depending on the application, taking into account the coil resistance. For applications such as micro-generators, micro-vibrators, and electromagnets, a coil pitch of 5 μm to 20 μm is preferable. The line width is approximately half the coil pitch.

[0023] The coil electrodes 122 (322) are attached in such a way that they are connected to both ends of the coil, and their size is approximately 5 to 10 times the coil wire width.

[0024] <Outer insulating coating> The outer insulating coating 23 electrically insulates the conductive coil from the outside and also protects the conductive coil and the insulating coating itself from environmental damage, and has a thickness of 100 μm or less, preferably 30 μm to 10 μm.

[0025] <Periodic spacing of coil electrodes> The coil electrodes 322 can be realized by providing wide open spaces between the coils 32 at regular intervals and exposing coil electrodes 322 wider than the coil wire width at both ends of the coil 321. This is suitable for applications such as pickup coils, electromagnetic coil magnets, and micro-generators that use coils to detect changes in the magnetization state of magnetic wire.

[0026] <Method of manufacturing magnetic wire with microcoil and microcoil element> A method for producing a magnetic wire with a microcoil (microcoil element) will be described with reference to the flow chart of FIG. Here, the microcoil element 1 is manufactured by manufacturing a microcoil-attached magnetic wire 3 consisting of a large number of microcoil elements 30, and finally dividing it into individual pieces to produce the microelements 1.

[0027] Step 401; A magnetic wire with an insulating coating (hereinafter referred to as a magnetic wire) is placed in a vapor deposition device. The length of the magnetic wire (microcoil formation portion) is 50 mm to 300 mm, depending on the size of the inside of the deposition device, the coil pitch and number of coil turns, and the number of microcoil elements. When the thickness of the insulating coating of the magnetic wire is thin in consideration of the diameter of the magnetic wire, the insulating coating may be thickened by coating an insulating resin or the like on the insulating coating in advance.

[0028] Step 402; While the magnetic wire is being rotated, a highly conductive metal coating is uniformly deposited on the surface of the wire. The thickness of the metal coating is 0.5 μm to 3 μm.

[0029] Step 403; A uniform resist coating is then applied over the metal coating. The coating method includes a method of uniformly coating the magnetic wire by spraying, and a method of coating the magnetic wire and then rotating it to make it uniform.

[0030] Step 404; A wire feed device capable of rotating and feeding at a constant speed is installed in the exposure device, and the magnetic wire is rotated once while being exposed using a mask with a slit for exposing the coil body. The feed amount during this process is the pitch amount of the coil body, and the exposure time is set to match the feed time. Subsequently, a mask having slits for exposing the coil electrodes is used to expose the coil electrodes on both ends of the coil.

[0031] Step 405; After exposure, etching is performed to remove the resist except in the exposed areas, and then the metal in the areas where the resist has been removed is removed by chemical etching, thereby forming a coil body and coil electrodes on the insulating coating on the surface of the magnetic wire.

[0032] Step 406; Next, an external insulating coating is applied to electrically insulate the coil, which is made up of the coil body and coil electrodes, from the outside.

[0033] Step 407; A magnetic wire with a microcoil is formed.

[0034] Next, the process for fabricating a coil element from the magnetic wire with a microcoil is as follows. Step 408; The microcoil elements arranged along the microcoil-attached magnetic wire are cut out one by one to form individual pieces.

[0035] Step 409; A microcoil element. [Example]

[0036] Examples of the present invention will be described below. A magnetic wire 1 with a microcoil according to the embodiment is shown in FIGS. The magnetic wire 31 is a micro-coiled magnetic wire consisting of a magnetic wire 21 as a magnetic core, a conductive coil 22, and an outer insulating coating 23. The magnetic wire 31 is coated with a glass insulating material 21G having a film thickness of 1.0 μm. The magnetic wire 21 has a diameter of 500 μm and is used for a micro-generator, a micro-oscillator, or an electromagnet.

[0037] Coil body 121 of conductive coil 12 is made of Au, a highly conductive material, with a coil pitch of 10 μm and 2000 turns.

[0038] The coil electrodes 122 are attached in such a way that they are connected to both ends of the coil, and their size is 25 μm.

[0039] The outer insulating coating 23 provides insulation between the conductive coils 12 (32) and electrically insulates the conductive coils 12 (32) from the outside, and also protects the conductive coils and the insulating coating itself from environmental damage, and has a film thickness of 30 μm.

[0040] Therefore, the size of the microcoil element as a unit element is 25 mm in length and approximately 530 μm in diameter.

[0041] The conductive coil is manufactured by depositing a metal film onto the insulating coating of a 200 mm long magnetic wire, then applying a resist on top of that, creating slits in a rotary exposure mask corresponding to the number of turns of each coil, leaving spaces between the coil units, and then using this mask for rotary exposure. Next, a mask corresponding to the coil electrodes at both ends of the single coil is prepared and exposed to light, the resist other than the exposed areas is removed by development, and the metal in the areas where the resist has been removed is removed by chemical etching, forming the coil body and coil electrodes.

[0042] Next, an outer insulating coating is applied onto the conductive coil consisting of the coil body and the coil electrode, and the outer insulating coating is removed from the coil electrode so that it can be connected to the outside.

[0043] Eight microcoil elements, each 25 mm long including the unit element and spaces on both ends, are cut out by dicing. [Industrial Applicability]

[0044] As described above, the microcoil of the present invention is ultra-small and has high-performance electro-magnetic conversion capability, making it applicable to a wide range of fields, such as micro-generators, micro-oscillators, and micro-electromagnets. [Explanation of symbols]

[0045] 1;Magnetic wire with micro coil 11: Magnetic wire with insulating coating 12;Conductive coil 121; Coil body 122: Coil electrode 2: Magnetic wire with microcoil (A1-A2 cross section) 21: Magnetic wire with insulating coating 210;Magnetic wire 21G: Insulating coating (insulating glass) 22: Conductive coil 23: Outer insulating coating 3;Magnetic wire with micro coil 30: Unit element (microcoil element) 31;Magnetic wire 32;Conductive coil 321; Coil body 322: Coil electrode

Claims

1. A magnetic wire with a microcoil, which comprises a magnetic wire with an insulating coating (hereinafter referred to as the magnetic wire), a conductive coil (hereinafter referred to as the coil), and an outer insulating coating, The magnetic wire has a diameter of 5 μm to 1 mm and an effective magnetic permeability of 1000 or more, and is coated on its outer periphery with an insulating material such as glass, resin, or oxide having a thickness of 2 μm or less, The coil comprises a coil body that wraps around the magnetic wire and coil electrodes on both ends of the coil body, and the coil body has a coil pitch of 2 μm to 10 μm and is made of a conductive material with excellent conductivity, such as Cu, Al, or Au, and the coils are periodically spaced along the magnetic wire; The outer insulating coating is a coating for providing electrical insulation between the coil and the outside and for protecting the coil element from environmental damage, and has a thickness of 100 μm or less. A magnetic wire with a microcoil.

2. 2. The microcoil element according to claim 1, wherein the magnetic wire with a microcoil is divided into individual pieces and extracted as a single microcoil element.

3. The method for producing a magnetic wire with a microcoil (microcoil element) according to claim 1 comprises the steps of: (1) A magnetic wire with an insulating coating (hereinafter referred to as magnetic wire) is placed in a vapor deposition device. (2) While rotating the magnetic wire, a metal coating having excellent conductivity is uniformly deposited on the surface of the wire; (3) Subsequently, a uniform resist coating is applied onto the metal coating; (4) A wire feed device capable of rotating and feeding at a constant speed is installed in the exposure device, and the magnetic wire is rotated once while being exposed using a mask having a slit for exposing the coil body. The feed amount at this time is the pitch amount of the coil body, and the exposure time is set to match the feed time. Next, a mask having slits for exposing the coil electrodes is used to expose the coil electrodes on both ends of the coil. (5) After exposure, development is performed, the resist is removed from areas other than the exposed areas, and then the metal from the areas where the resist has been removed is removed by chemical etching, thereby forming a coil body and a coil electrode on the insulating coating on the surface of the magnetic wire; (6) Next, an external insulating coating is applied to electrically insulate the coil, which is made up of the coil body and the coil electrodes, from the outside.

1. A method for producing a magnetic wire with a microcoil element (microcoil element), comprising:

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