JP2001052947A - Coil, electromagnet, and manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a microfabricated coil and a microfabricated electromagnet each having a three-dimensional structure, and a method of manufacturing these coils and electromagnets with high accuracy. SOLUTION: This method of manufacturing a coil comprises the steps of forming a semicylindrical recess la having a sloped surface (1b) on the surface of a substrate l forming a plurality of first spaced conductors 5a on the surface of the recess 1a with the surface (1b) forming a cylinder 6a made of an insulating substance, a half of which is buried in the recess 1a and the remaining half of which projects from the surface of the substrate and forming a plurality of second spaced conductors 5b to form a single coil on the surface of the cylinder 6a by connecting them with the conductors 5a. Thus, there are provided a coil formed by this method, an electromagnet having the coil formed around its magnetic core, and a method for manufacturing the electromagnet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro coil, ME, used as an inductance element in an electronic circuit.
MS (microelectromechanical)
The present invention relates to a fine electromagnet used for a system and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as an inductance element of an electronic circuit, a planar type in which metal wiring is routed in a plane has been mainly used. When a coil is manufactured by winding a wiring by mechanical work, processing accuracy and strength become problems when the coil is miniaturized. Therefore, for example, a spiral wiring is patterned on a substrate and used as a planar coil. However, in the case of a planar coil, there is a problem that the magnetic efficiency (magnetism generation efficiency and coupling efficiency) is generally low despite the large occupied area.

To solve the above problem, Japanese Patent Application Laid-Open No.
Japanese Patent No. 64359 discloses an electromagnet including a coil having a three-dimensional structure manufactured by multilayer plating. This electromagnet has a structure in which a magnetic core 103 is formed on a substrate 101 via an insulating layer 102, as shown in FIG. A coil bottom wiring 104 is formed on the surface of the substrate 101. A coil-side wiring 105 is formed with the magnetic core 103 interposed therebetween, and a coil top wiring 106 is formed thereabove. The coil bottom wiring 104 is electrically connected to the coil top wiring 106 via the coil side wiring 105,
These wirings form one coil. According to this electromagnet, the coil is formed without the step of winding the wiring,
The size of the electromagnet can be reduced as compared with the case of the planar type.

[0004]

Conventionally, a planar coil or an electromagnet used as an inductance component of an electronic circuit occupies a large area, which hinders miniaturization of the electronic circuit. On the other hand, Japanese Patent Application Laid-Open
According to the small electromagnet described in JP-A-264359, the coil cross section is rectangular due to process restrictions, but the coil side wiring 105 and the coil top wiring 106
Since the thickness of the plating layer becomes about 20 μm,
The length of the side of the rectangle corresponding to the coil diameter is at least 40μ
m. As the electromagnet applied to the MEMS, a further downsized electromagnet is required.

In the electromagnet described in Japanese Patent Application Laid-Open No. 8-264359, the wiring 105 on both sides of the coil is formed by filling the contact hole 102a formed in the insulating layer 102 with plating. Therefore, when the contact hole 102a is miniaturized, the aspect ratio increases,
In some cases, the contact hole 102a cannot be filled by plating. Alternatively, it becomes difficult to form the fine contact hole 102a having a high aspect ratio by dry etching. Therefore, Japanese Patent Application Laid-Open No.
According to the method for manufacturing a small electromagnet described in Japanese Patent No. 64359, it is difficult to form a sufficiently miniaturized coil or electromagnet applicable to MEMS.

[0006] The present invention has been made in view of the above problems, and it is therefore an object of the present invention to provide a fine coil, a fine electromagnet having a three-dimensional structure, and a method of manufacturing the same.

[0007]

In order to achieve the above-mentioned object, a coil according to the present invention is a coil in which a conductor is spirally wound, and the conductor has a length substantially half of one turn of the spiral. A plurality of conductive wire pieces connected to each other. The coil of the present invention is preferably characterized in that the conductive wire is a solenoid coil wound in a cylindrical shape at equal intervals. The coil of the present invention is preferably characterized in that half of the coil is embedded in a recess formed in the surface of the substrate. Preferably, the coil according to the present invention is characterized in that the depression has a semi-cylindrical shape obtained by substantially bisecting a cylinder having a circular or elliptical cross section. The coil of the present invention is preferably arranged such that the semi-cylindrical depression is opposed to the depression such that a distance between two opposing surfaces of the depression is wider on the substrate surface as compared to a bottom of the depression. The two surfaces are inclined surfaces. The coil of the present invention is further preferably characterized in that a wiring connected to the coil is formed on the surface of the inclined surface. The coil of the present invention is preferably characterized in that it is wound around a cylinder made of an insulating material.

Alternatively, the coil according to the present invention is preferably characterized in that the depression has a shape obtained by substantially dividing a polygonal prism into two equal parts. Preferably, the coil of the present invention is configured such that the bottom surface is an inclined surface such that a distance between two opposing bottom surfaces of the polygonal pillar is wider on the substrate surface as compared to a bottom portion of the depression. Features. The coil of the present invention is further preferably characterized in that a wiring connected to the coil is formed on the surface of the inclined surface. The coil of the present invention is preferably wound around a polygonal pillar made of an insulator.

[0009] This makes it possible to miniaturize the coil as compared with a coil formed by winding one conductive wire around a cylinder, for example. Further, since the coil of the present invention is formed by being buried in the depression on the surface of the substrate, the strength of the coil is maintained even when the conductor is thinned, and the conductor can be processed with high accuracy. Further, the fine coil of the present invention is mounted on the same substrate as the semiconductor integrated circuit,
By forming the semiconductor device as an inductance component connected to the semiconductor integrated circuit, the semiconductor device can be highly integrated and miniaturized.

In order to achieve the above object, an electromagnet of the present invention is a fine electromagnet having a coil in which a conductive wire is spirally wound and a magnetic core formed in the coil, wherein the conductive wire is It is characterized in that a plurality of conductor pieces having a length substantially half of one turn of the helix are connected. The electromagnet of the present invention is preferably characterized in that the coil is a solenoid coil in which the conductive wires are wound in a columnar shape at equal intervals. The electromagnet of the present invention is preferably characterized in that half of the coil is embedded in a recess formed on the surface of the substrate. The electromagnet according to the present invention is preferably characterized in that the depression has a semi-cylindrical shape obtained by substantially bisecting a cylinder having a circular or elliptical cross section. The electromagnet of the present invention is preferably such that the semi-cylindrical depression is opposed to the depression such that the distance between two opposing surfaces of the depression is wider on the substrate surface than at the bottom of the depression. The two surfaces are inclined surfaces. The electromagnet of the present invention is further preferably characterized in that a wiring connected to the coil is formed on the surface of the inclined surface.

Alternatively, the electromagnet of the present invention is preferably characterized in that the depression has a shape obtained by substantially dividing a polygonal prism into two equal parts. The electromagnet of the present invention is preferably configured such that the bottom surface is an inclined surface such that a distance between two opposing bottom surfaces of the polygonal pillar is wider on the substrate surface than a bottom portion of the depression. Features. The electromagnet of the present invention is further preferably characterized in that a wiring connected to the coil is formed on the surface of the inclined surface.

This makes it possible to miniaturize the electromagnet as compared with an electromagnet formed by winding one conductive wire around the magnetic core. Therefore, the electromagnet of the present invention can be suitably used for MEMS. Further, since the electromagnet of the present invention is formed by being buried in the depression on the surface of the substrate, the strength of the coil is maintained even when the conductor is made thinner, and the conductor can be processed with high accuracy.

Further, in order to achieve the above object, a method of manufacturing a coil according to the present invention includes a step of forming a semi-cylindrical dent on a substrate surface, and a step of forming a plurality of discrete first conductors on the dent surface. Forming a cylinder made of an insulator half of which is embedded in the depression and the other half of which protrudes from the substrate surface; and
Forming a plurality of discrete second conductors that are connected to the first conductor to form one coil.

The method for manufacturing a coil according to the present invention is preferably
The step of forming the semi-cylindrical recess includes the step of forming a first resist with a substantially uniform thickness on the substrate surface, and the step of forming the first resist by photolithography using a photomask having a gradation. Forming a semi-cylindrical dent on the surface of the substrate, etching the first resist and the substrate, and removing the first resist,
Duplicating a depression on the first resist surface on the substrate surface.

The method for manufacturing a coil of the present invention is preferably
The step of forming the first conductive wire includes forming a first conductor layer on the surface of the depression formed in the substrate, and spraying a resist resin on the surface of the first conductor layer. Forming a second resist with a substantially uniform thickness in the depression, processing the second resist into a pattern of the first conductive wire by photolithography, and masking the second resist. Etching the first conductor layer.

The method for manufacturing a coil of the present invention is preferably
The step of forming the cylinder includes the steps of forming an insulating film on the substrate including the inside of the depression, flattening the surface of the insulating film, and forming a third layer with a substantially uniform thickness on the surface of the insulating film.
Forming a resist, and performing photolithography on the third resist using a photomask having a gradation, and forming the third resist in a semi-cylindrical shape having a curved surface only above the depression of the substrate. And a step of performing etching on the third resist and the insulating film to remove the third resist and replicating the semi-cylindrical shape of the surface of the third resist into the insulating film. It is characterized by the following.

The method for manufacturing a coil according to the present invention is preferably
Forming the second conductor, forming a second conductor layer on the surface of the cylinder protruding on the substrate;
Forming a fourth resist with a substantially uniform thickness by spraying a resist resin on the surface of the second conductor layer; and applying the fourth resist by photolithography to the pattern of the second conductive wire. And etching the second conductive layer using the fourth resist as a mask.

Preferably, the method for manufacturing a coil according to the present invention comprises:
The step of forming the semi-cylindrical dent may include removing two opposing surfaces of the dent so that a distance between two opposing surfaces of the dent is wider on the substrate surface as compared to a bottom of the dent. The method is characterized by including a step of forming an inclined surface. In the method for manufacturing a coil of the present invention, the step of forming the first conductor preferably further includes a step of forming a first wiring connected to the coil on a surface of the inclined surface. I do.

The method for manufacturing a coil according to the present invention is preferably
The step of forming the cylinder includes two opposing surfaces of the cylinder such that a distance between two opposing surfaces of the cylinder is wider on the substrate surface compared to a top portion of the cylinder protruding from the substrate surface. It is characterized by including a step of making the surface an inclined surface. In the method of manufacturing a coil according to the present invention, the step of forming the second conductor preferably further includes a step of forming a second wiring connected to the coil on a surface of the inclined surface. I do. The method for manufacturing a coil according to the present invention includes:
Preferably, the method further comprises a step of removing the cylinder after forming the second conductive wire and forming the coil connected to the first conductive wire.

In order to achieve the above object, a method of manufacturing a coil according to the present invention comprises the steps of: forming a hollow having a shape obtained by substantially dividing a polygonal prism into two on a substrate surface;
Forming a plurality of discrete first conductive wires; and forming a polygonal pillar made of an insulator, half of which is embedded in the recess, and the other half of which protrudes from the substrate surface,
Forming a plurality of discrete second conductors on the surface of the cylinder to form one coil by connecting to the first conductor.

Thus, it is possible to form a coil having a three-dimensional structure with high precision. According to the coil manufacturing method of the present invention, since the coil is formed by being embedded in the depression on the substrate surface, the strength of the conductor and the coil is maintained even when the conductor is made thin. Further, the conductive wire can be thinned within the allowable range of the resolution of photolithography and the processing accuracy of etching, so that the coil can be miniaturized. Further, in the depression serving as the coil mold, the facing surface is an inclined surface, and wiring is formed on the surface of the inclined surface, whereby disconnection of the wiring connected to the coil can be prevented.

Further, in order to achieve the above object, a method for manufacturing an electromagnet according to the present invention comprises a step of forming a semi-cylindrical depression on the surface of a substrate; Forming a first insulating film covering the first conductive wire on the surface of the recess, and embedding half of the recess in the recess and projecting the other half to the substrate surface Forming a cylinder made of a magnetic material to be formed, forming a second insulating film continuous with the first insulating film on the surface of the cylinder, and forming the second insulating film on the surface of the second insulating film. Forming a plurality of discrete second conductors by connecting to one conductor to form one coil.

The method for producing an electromagnet of the present invention is preferably
The step of forming the semi-cylindrical recess includes the step of forming a first resist with a substantially uniform thickness on the substrate surface, and the step of forming the first resist by photolithography using a photomask having a gradation. Forming a semi-cylindrical dent on the surface of the substrate, etching the first resist and the substrate, and removing the first resist,
Duplicating a depression on the first resist surface on the substrate surface.

The method for manufacturing an electromagnet of the present invention is preferably
The step of forming the first conductive wire includes forming a first conductor layer on the surface of the depression formed in the substrate, and spraying a resist resin on the surface of the first conductor layer. Forming a second resist with a substantially uniform thickness in the depression, processing the second resist into a pattern of the first conductive wire by photolithography, and masking the second resist. Etching the first conductor layer.

The method for manufacturing an electromagnet of the present invention is preferably
The step of forming the cylinder includes forming a magnetic layer on the substrate including the inside of the depression, flattening the surface of the magnetic layer, and forming a substantially uniform thickness on the surface of the magnetic layer. Forming a third resist, and performing photolithography on the third resist by using a photomask having a gradation, and forming the third resist in a semi-cylindrical shape having a curved surface only above the depression of the substrate. 3) a step of leaving the resist, and etching the third resist and the magnetic layer to copy the semi-cylindrical shape of the surface of the third resist to the magnetic layer while removing the third resist. And a step of performing

The method for producing an electromagnet of the present invention is preferably
The step of forming the second conductive wire includes forming a second conductor layer on the surface of the second insulating film, and spraying a resist resin on the surface of the second conductor layer. A step of forming a fourth resist with a substantially uniform thickness, a step of processing the fourth resist into a pattern of the second conductive wire by photolithography, and a step of forming the second resist using the fourth resist as a mask. Etching the conductor layer.

The method for producing an electromagnet of the present invention is preferably
The step of forming the semi-cylindrical dent may include removing two opposing surfaces of the dent so that a distance between two opposing surfaces of the dent is wider on the substrate surface as compared to a bottom of the dent. The method is characterized by including a step of forming an inclined surface. In the method for manufacturing an electromagnet according to the present invention, the step of forming the first conductor preferably includes a step of forming a first wiring connected to the coil on a surface of the inclined surface. I do.

The method for producing an electromagnet of the present invention is preferably
The step of forming the cylinder includes two opposing surfaces of the cylinder such that a distance between two opposing surfaces of the cylinder is wider on the substrate surface compared to a top portion of the cylinder protruding from the substrate surface. It is characterized by including a step of making the surface an inclined surface. In the method for manufacturing an electromagnet according to the present invention, the step of forming the second conductor preferably further includes a step of forming a second wiring connected to the coil on a surface of the inclined surface. I do.

In order to achieve the above object, a method of manufacturing an electromagnet according to the present invention comprises the steps of: forming a depression having a shape obtained by substantially dividing a polygonal prism into two equal parts on a substrate surface;
A step of forming a plurality of discrete first conductors, a step of forming a first insulating film covering the first conductor on the surface of the depression, and half of the depression filling the depression, Forming a polygonal prism made of a magnetic material, half of which protrudes from the substrate surface; forming a second insulating film continuous with the first insulating film on the surface of the polygonal prism;
Forming a plurality of discrete second conductive wires on the surface of the insulating film to form one coil by connecting to the first conductive wire.

This makes it possible to form an electromagnet in which a fine coil having a three-dimensional structure is formed around the magnetic core with high precision. According to the manufacturing method of the electromagnet of the present invention, the fine coil is formed by being embedded in the depression on the surface of the substrate, so that the strength of the conductor and the coil is maintained even when the conductor is thinned. Also, within the allowable range of the resolution of photolithography and the processing accuracy of etching,
Since the conductive wire can be made thinner, the electromagnet including the coil can be made finer. Further, in the depression serving as a mold for the electromagnet, the facing surface is an inclined surface, and wiring is formed on the surface of the inclined surface, whereby disconnection of the wiring connected to the coil can be prevented.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a coil, an electromagnet and a method of manufacturing the same according to the present invention will be described with reference to the drawings. (Embodiment 1) FIGS. 1 to 3 are views showing a manufacturing process of a method for manufacturing a coil of this embodiment. FIG. 3 (d-1) is a sectional view of the coil of this embodiment, and FIG. 2) is a top view of the coil of the present embodiment. According to the coil manufacturing method of the present embodiment, as shown in FIGS. 3D-1 and 3D-2, for example, a miniaturized coil having a coil diameter of 4 μm and a coil length of 12 μm is connected to an electronic circuit (non- (Not shown) on the same substrate. By using the coil of the present embodiment as an inductance component of an electronic circuit, it is possible to miniaturize the electronic circuit.

Next, a method of manufacturing the coil of the present embodiment will be described. First, as shown in FIGS. 1A-1 to 1A-3, a photoresist 2 having a semi-cylindrical concave portion 2a is formed on a substrate 1. FIG. 1 (a
-2) is a top view, and FIG. 1 (a-1) is a top view of FIG.
2) is a cross-sectional view taken along line XX ′, and FIG.
It is sectional drawing in YY 'of (a-2). FIG. 1 (a
As shown in -3), an inclined surface 2b is provided at an end of the concave portion.

By using, for example, an 8-inch Si wafer on which an LSI is fabricated,
A fine coil is formed on the same substrate. The photoresist 2 having a semicylindrical concave portion can be formed by applying a resist material on the substrate 1 and exposing the substrate to ultraviolet light using a photomask having gradation. A photomask having a gradation can be obtained by forming an organic material, for example, as a light shielding material on a light-transmitting mask substrate with a predetermined gradation.

Next, as shown in FIGS. 1 (b-1) to 1 (b-3), the substrate 1 is etched using the photoresist 2 as a mask. FIG. 1B-2 is a top view, and FIG.
1B is a cross-sectional view taken along line XX ′ of FIG. 1B-2, and FIG. 1B-3 is a cross-sectional view taken along line YY ′ of FIG. 1B-2. Semi-cylindrical recess 2a by etching
When the resist pattern on the inclined surface 2b is transferred to the substrate 1, a semi-cylindrical concave portion 1a and an inclined surface 1b are formed on the surface of the substrate 1. The etching of the substrate 1 is performed by, for example, dry etching so that the etching selectivity between the photoresist 2 and the substrate 1 becomes appropriate.

The semi-cylindrical concave portion 1a on the surface of the substrate 1 has, for example, a width W of 4 μm, a maximum depth D of 2 μm, and a length L of 12 μm.
m. Further, as shown in FIG.
The angle θ of the inclined surface 1b is, for example, 60 °. Recess 1a
Is provided with the inclined surface 1b, so that the concave portion 1a
The disconnection of the Al wiring formed therein is prevented. Therefore, the angle θ of the inclined surface 1b is appropriately set within a range in which the disconnection of the Al wiring is prevented.

Next, as shown in FIG.
An Al film 3 having a uniform thickness is formed on the surface of the substrate 1 including the inside by, for example, sputtering. The thickness of the Al film 3 is, for example, 1.0 μm. Subsequently, as shown in FIG. 2A, a photoresist 4 having a uniform thickness is formed by spraying the photoresist. By forming the photoresist 4 by spraying instead of ordinary spin coating or the like, a photoresist having a uniform thickness can be formed regardless of surface irregularities. Here, a more uniform film can be formed by applying a bias to the silicon wafer as the substrate 1 and charging the fine particles of the photoresist.

Next, as shown in FIGS. 2 (b-1) and (b-2), the Al film 3 is etched to form an Al wiring 5a.
To form FIG. 2B-2 is a top view, and FIG.
-1) is a sectional view taken along line XX ′ of FIG. 2B-2. After forming the photoresist 4 of FIG. 2A, the photoresist 4 in the concave portion 1a is exposed by using a mask aligner having a long-distance optical system having a large depth of focus, and a pattern corresponding to half of the coil is transferred. I do. Further, dry etching is performed on the Al film 3 using the photoresist 4 processed into the coil pattern as a mask. As a result, the Al wiring 5a having a thickness of, for example, 1 μm is formed in the semi-cylindrical concave portion 1a formed in the silicon substrate 1. As shown in FIG. 2B-2, the coil pitch I is, for example, 3 μm.

Next, as shown in FIG.
For example, a silicon oxide film 6 is formed as an insulating film on the substrate 1 including the inside, and the semi-cylindrical concave portion 1a is completely buried. The silicon oxide film 6 is formed, for example, by plasma CVD (chemical).
The film can be formed by an al deposition method. Then, for example, CMP (chem
ical mechanical polish
g) is performed to flatten the surface of the silicon oxide film 6.

Next, as shown in FIG. 2D, a semi-cylindrical photoresist 7 is formed on the silicon oxide film 6.
The semi-cylindrical photoresist 7 can be formed by applying a resist material on the silicon oxide film 6 and then irradiating the ultraviolet rays using a photomask having gradation. As a photomask having a gradation, a photomask similar to the photomask for forming the photoresist 2 can be used. Although not shown, an inclined surface is formed at the end of the photoresist 7. The angle between the inclined surface and the surface of the silicon oxide film 6 is an angle θ shown in FIG. The inclined surface is provided for the purpose of preventing disconnection of Al wiring 5b formed in a subsequent step.

Next, as shown in FIG. 3A, the photoresist 7 and the silicon oxide film 6 are etched.
By performing dry etching, for example, so that the etching selectivity between the photoresist 7 and the silicon oxide film 6 is appropriate, a semi-cylindrical resist pattern having an inclined surface is transferred to the silicon oxide film 6. Thus, a cylinder 6a made of silicon oxide and having an inclined surface on the bottom surface is formed on the concave portion 1a of the substrate 1.

Here, when the silicon oxide film 6 is etched, the Al film formed on the edge of the concave portion 1a of the substrate 1 is formed.
It is necessary to expose the wiring 5a, that is, the uppermost part of the Al wiring 5a. By exposing the uppermost portion of the Al wiring 5a, the wiring 5b formed in the subsequent step is connected to the wiring 5a, and a coil is formed. In order to expose the uppermost portion of the Al wiring 5a, the silicon oxide film 6 may be locally removed and a cut may be made in the cylinder 6a.

Next, as shown in FIG.
Then, an Al film 8 having a uniform thickness is formed on the surface of the substrate 1 by, for example, sputtering. The Al film 8 is formed with the same thickness as the Al film 3, for example, 1.0 μm. Subsequently, FIG.
As shown in (c), a photoresist 9 having a uniform thickness is formed by spraying the photoresist. By spraying the photoresist 9 instead of spin coating or the like, a photoresist having a uniform film thickness can be formed regardless of surface irregularities. here,
By applying a bias to the silicon wafer as the substrate 1 to charge the fine particles of the photoresist, a more uniform film can be formed.

Next, as shown in FIGS. 3D-1 and 3D-2, the Al film 8 is etched to form the Al wiring 5b.
To form FIG. 3D-2 is a top view, and FIG.
-1) is a sectional view taken along line XX ′ of FIG. 3D-2. In order to form the Al wiring 5b, first, after forming the photoresist 9 of FIG. 3C, the photoresist 9 on the surface of the cylinder 6a is exposed using a mask aligner having a long-distance optical system having a large depth of focus. Then, a pattern corresponding to half of the coil is transferred. Further, dry etching is performed on the Al film 8 using the photoresist 9 processed into the coil pattern as a mask. Thus, an Al wiring 5b having a thickness of, for example, 1 μm is formed on the surface of the cylinder 6a.

Through the above steps, the Al wiring 5b and the Al wiring 5a are connected, and the pitch I is changed as shown in FIG.
Is formed, for example, with a length of 3 μm. This coil is connected to an LSI formed on the substrate 1,
It becomes an inductance component. According to the coil manufacturing method of the embodiment of the present invention described above, it becomes possible to form a fine coil having a three-dimensional structure and connected to an LSI with high accuracy on a substrate such as a silicon substrate.

(Embodiment 2) FIGS. 4 to 6 are views showing manufacturing steps of a method of manufacturing an electromagnet according to the present embodiment. The steps shown in FIGS. 1 to 2 (b-1) and (b-2) are common to the coil manufacturing method of the first embodiment. FIG. 6 (c-
1) is a cross-sectional view of the electromagnet of the present embodiment, and FIG. 6C-2 is a top view of the electromagnet of the present embodiment. According to the method of manufacturing an electromagnet of the present embodiment, FIGS.
As shown in 2), for example, a coil diameter of 4 μm and a coil length of 1
A fine electromagnet having a micronized coil of 2 μm and a coil core made of Ni can be formed. The electromagnet of the present embodiment can be suitably used for MEMS.

Next, a method for manufacturing the electromagnet of the present embodiment will be described. First, as shown in FIGS. 1A-1 to 1A-3, a photoresist 2 having a semi-cylindrical concave portion 2a is formed on a substrate 1. FIG. 1 (a
-2) is a top view, and FIG. 1 (a-1) is a top view of FIG.
2) is a cross-sectional view taken along line XX ′, and FIG.
It is sectional drawing in YY 'of (a-2). FIG. 1 (a
As shown in -3), an inclined surface 2b is provided at an end of the concave portion.

By using, for example, an 8-inch Si wafer on which an LSI has been fabricated,
And a fine electromagnet can be formed on the same substrate. The photoresist 2 having a semicylindrical concave portion can be formed by applying a resist material on the substrate 1 and irradiating the substrate with ultraviolet rays using a photomask having gradation. A photomask having a gradation can be obtained by forming an organic material, for example, as a light shielding material on a light-transmitting mask substrate with a predetermined gradation.

Next, as shown in FIGS. 1 (b-1) to 1 (b-3), the substrate 1 is etched using the photoresist 2 as a mask. FIG. 1B-2 is a top view, and FIG.
1B is a cross-sectional view taken along line XX ′ of FIG. 1B-2, and FIG. 1B-3 is a cross-sectional view taken along line YY ′ of FIG. 1B-2. Semi-cylindrical recess 2a by etching
When the resist pattern on the inclined surface 2b is transferred to the substrate 1, a semi-cylindrical concave portion 1a and an inclined surface 1b are formed on the surface of the substrate 1. The etching of the substrate 1 is performed by, for example, dry etching so that the etching selectivity between the photoresist 2 and the substrate 1 becomes appropriate.

The semi-cylindrical concave portion 1a on the surface of the substrate 1 has, for example, a width W of 4 μm, a maximum depth D of 2 μm, and a length L of 12 μm.
m. Further, as shown in FIG.
The angle θ of the inclined surface 1b is, for example, 60 °. Recess 1a
Is provided with the inclined surface 1b, so that the concave portion 1a
The disconnection of the Al wiring formed therein is prevented. Therefore, the angle θ of the inclined surface 1b is appropriately set within a range in which the disconnection of the Al wiring is prevented.

Next, as shown in FIG.
An Al film 3 having a uniform thickness is formed on the surface of the substrate 1 including the inside by, for example, sputtering. The thickness of the Al film 3 is, for example, 1.0 μm. Subsequently, as shown in FIG. 2A, a photoresist 4 having a uniform thickness is formed by spraying the photoresist. By forming the photoresist 4 by spraying instead of ordinary spin coating or the like, a photoresist having a uniform thickness can be formed regardless of surface irregularities. Here, a more uniform film can be formed by applying a bias to the silicon wafer as the substrate 1 and charging the fine particles of the photoresist.

Next, as shown in FIGS. 2 (b-1) and 2 (b-2), the Al film 3 is etched to form an Al wiring 5a.
To form FIG. 2B-2 is a top view, and FIG.
-1) is a sectional view taken along line XX ′ of FIG. 2B-2. After forming the photoresist 4 of FIG. 2A, the photoresist 4 in the concave portion 1a is exposed by using a mask aligner having a long-distance optical system having a large depth of focus, and a pattern corresponding to half of the coil is transferred. I do. Further, dry etching is performed on the Al film 3 using the photoresist 4 processed into the coil pattern as a mask. As a result, the Al wiring 5a having a thickness of, for example, 1 μm is formed in the semi-cylindrical concave portion 1a formed in the silicon substrate 1. As shown in FIG. 2B-2, the coil pitch I is, for example, 3 μm.

Next, as shown in FIG.
A silicon oxide film 11 having a uniform thickness, for example, 0.5 μm is formed as an insulating film inside and on the substrate 1. Subsequently, as shown in FIG. 4B, a photoresist 12 covering only the silicon oxide film 11 in the concave portion 1a is formed.
Thereafter, as shown in FIG.
Is used as a mask, for example, dry etching is performed on the silicon oxide film 11 to remove the silicon oxide film 11 other than the semi-cylindrical concave portion 1a. Next, as shown in FIG.
A Ni film 13 is deposited on the silicon oxide film 11 and the substrate 1 by, for example, sputtering to form a semi-cylindrical concave portion 1.
a is completely embedded. Thereafter, for example, CMP is performed, and N
The surface of the i-film 13 is flattened.

Next, as shown in FIG.
A semi-cylindrical photoresist 14 is formed on 3. The semi-cylindrical photoresist 14 can be formed by applying a resist material on the Ni film 13 and then irradiating ultraviolet rays using a photomask having gradation. As a photomask having a gradation, a photomask similar to the photomask for forming the photoresist 2 can be used. Although not shown, an inclined surface is formed at an end of the photoresist 14. The angle between the inclined surface and the surface of the Ni film 13 is an angle θ shown in FIG. 1A-3, for example, 60 °. The inclined surface is formed by Al
It is provided for the purpose of preventing disconnection of the wiring 5b.

Next, as shown in FIGS. 5A-1 and 5A-2, the photoresist 14 and the Ni film 13 are etched. By performing dry etching, for example, so that the etching selectivity between the photoresist 14 and the Ni film 13 is appropriate, a semi-cylindrical resist pattern having an inclined surface is transferred to the Ni film 13. As a result, a cylinder 13a made of Ni on the concave portion 1a of the substrate 1 and having an inclined surface on the bottom surface is formed. The diameter of the cylinder 13a is approximately 3 μm. An Al wiring 5a is formed on the surface of the cylinder 13a on the substrate 1 side via the silicon oxide film 11.

Next, as shown in FIG.
For example, a silicon oxide film 15 having a uniform thickness is formed as an insulating film on the surface a and on the substrate 1. This insulating film has the same composition and thickness as the insulating film covering half of the cylinder 13a, that is, the silicon oxide film 11. Silicon oxide film 15 is connected to silicon oxide film 11.

Next, as shown in FIG. 5C, a photoresist 16 having a uniform thickness is formed on the silicon oxide film 15 by spraying the photoresist. By spraying the photoresist 16 instead of spin coating or the like, a photoresist having a uniform film thickness can be formed regardless of surface irregularities. Here, a more uniform film can be formed by applying a bias to the silicon wafer as the substrate 1 and charging the fine particles of the photoresist.

Thereafter, exposure is performed using a mask aligner having a long-distance optical system having a large depth of focus, and the cylinder 13a is exposed.
Photoresist 1 leaving only part of photoresist 16
6 is removed. Next, the silicon oxide film 15 is subjected to, for example, dry etching using the photoresist 16 remaining only in the cylinder 13a as a mask, to thereby obtain FIG.
As shown in FIG. 5, a cylinder 13a made of Ni is covered with silicon oxide films 11 and 15.

Here, when etching the silicon oxide film 15, the A formed on the edge of the concave portion 1 a of the substrate 1 is formed.
It is necessary to expose the l wiring 5a, that is, the uppermost part of the Al wiring 5a. By exposing the uppermost portion of the Al wiring 5a, the wiring 5b formed in the subsequent step is connected to the wiring 5a, and a coil is formed. In order to expose the uppermost part of the Al wiring 5a, the silicon oxide film 15 is locally removed,
A cut may be made.

Next, as shown in FIG.
An Al film 8 having a uniform film thickness is formed on the surface of the substrate a and the substrate 1 by, for example, sputtering. The Al film 8 is the Al film 3
It is formed with the same film thickness as, for example, 1.0 μm. Subsequently, as shown in FIG. 6B, a photoresist 17 having a uniform thickness is formed on the Al film 8 by spraying the photoresist. By spraying the photoresist 17 instead of spin coating or the like, it is possible to form a photoresist having a uniform thickness regardless of surface irregularities. Here, a more uniform film can be formed by applying a bias to the silicon wafer as the substrate 1 and charging the fine particles of the photoresist.

Next, as shown in FIGS. 6C-1 and 6C-2, the Al film 8 is etched to form the Al wiring 5b.
To form FIG. 6C-2 is a top view, and FIG.
-1) is a sectional view taken along line XX ′ in FIG. 6C-2. To form the Al wiring 5b, first, after forming the photoresist 17 of FIG. 6B, the photoresist 17 on the surface of the Al film 8 is exposed using a mask aligner having a long-distance optical system having a large depth of focus. To transfer the pattern corresponding to half of the coil. Further, using the photoresist 17 processed into the coil pattern as a mask, the Al film 8 is formed.
Dry etching. Thus, an Al wiring 5b having a thickness of, for example, 1 μm is formed on the surface of the cylinder 13a.

Through the above steps, the Al wiring 5b and the Al wiring 5a are connected, and the pitch I is changed as shown in FIG.
Is formed around the Ni cylinder 13a as the coil core. The above electromagnet of the present embodiment can be suitably used for MEMS.

Embodiments of the coil, electromagnet and manufacturing method of the present invention are not limited to the above description. For example, the dimensions of the coil or electromagnet, the type of metal or insulating film, the film forming means, and the like can be appropriately changed. Embodiment 1
When a low dielectric layer such as an organic silicon oxide film is used instead of the silicon oxide film constituting the cylinder 6a in the above, the inside of the coil can be hollowed out by performing ashing after completion of the coil. Also, the cross section of the coil or the electromagnet may be a polygon such as a rectangle instead of a circle or an ellipse. In addition, various changes can be made without departing from the gist of the present invention.

[0063]

According to the coil of the present invention, since it has a three-dimensional structure, the area occupied by the coil can be reduced as compared with the case where the coil is formed in a plane. According to the electromagnet of the present invention, the electromagnet includes a fine coil having a three-dimensional structure, and can be suitably used for MEMS. According to the coil manufacturing method of the present invention, a fine coil having a three-dimensional structure can be formed with high accuracy. ADVANTAGE OF THE INVENTION According to the manufacturing method of the electromagnet of this invention, the fine electromagnet including the fine coil which has a three-dimensional structure, and can be suitably used for MEMS can be formed with high precision.

[Brief description of the drawings]

FIGS. 1A to 1C are cross-sectional views or top views showing manufacturing steps of a method for manufacturing a coil or an electromagnet according to Embodiments 1 and 2. FIG.

FIGS. 2A to 2D are cross-sectional views or top views showing manufacturing steps of a method for manufacturing a coil according to the first embodiment, and FIGS. 2A and 2B are electromagnets according to the second embodiment; FIG. 7 is a cross-sectional view or a top view showing the manufacturing process of the manufacturing method of FIG.

FIGS. 3A to 3D are cross-sectional views or top views illustrating a manufacturing process of the coil manufacturing method according to the first embodiment.

FIGS. 4A to 4E are cross-sectional views illustrating manufacturing steps of an electromagnet manufacturing method according to a second embodiment.

FIGS. 5A to 5D are cross-sectional views or top views showing the manufacturing steps of the method for manufacturing an electromagnet according to the second embodiment.

FIGS. 6A to 6C are cross-sectional views or top views showing manufacturing steps of a method for manufacturing an electromagnet according to the second embodiment.

FIG. 7 is a perspective view of a conventional coil having a three-dimensional structure.

[Explanation of symbols]

1, 101: substrate, 1a, 2a: concave portion, 1b, 2b: inclined surface, 2, 4, 7, 9, 12, 14, 16, 17: photoresist, 3, 8: Al film, 5a, 5b: Al wiring,
6, 11, 15: silicon oxide film, 6a: cylinder of insulator (silicon oxide), 13: Ni film, 13a: cylinder of Ni (magnetic core), 102: insulating layer, 102a: contact hole, 103: magnetic Body core, 104: coil bottom wiring, 105: coil both side wiring, 106: coil top wiring.

Claims (41)

[Claims] 1. A coil in which a conductive wire is spirally wound, wherein the conductive wire is formed by connecting a plurality of conductive wire pieces having a length substantially half of one turn of the spiral. 2. The coil according to claim 1, wherein said coil is a solenoid coil in which said conductive wires are wound in a cylindrical shape at equal intervals. 3. The coil according to claim 1, wherein a half of said coil is embedded in a recess formed in a substrate surface. 4. The coil according to claim 3, wherein the recess has a semi-cylindrical shape obtained by substantially bisecting a cylinder having a circular or elliptical cross section. 5. The semi-cylindrical depression has two opposing surfaces of the depression such that the distance between two opposing surfaces of the depression is wider on the substrate surface than at the bottom of the depression. The coil according to claim 4, wherein is a slope. 6. The coil according to claim 5, wherein a wiring connected to the coil is formed on a surface of the inclined surface. 7. The coil according to claim 4, wherein said coil is wound around a cylinder made of an insulating material. 8. The coil according to claim 3, wherein said depression has a shape obtained by substantially dividing a polygonal prism into two equal parts. 9. The depression has an inclined surface such that a distance between two opposing bottom surfaces of the polygonal pillar is wider on a surface of the substrate than a bottom portion of the depression. 8. The coil according to 8. 10. The coil according to claim 9, wherein a wiring connected to the coil is formed on a surface of the inclined surface. 11. The coil according to claim 8, wherein the coil is wound around a polygonal pillar made of an insulator. 12. An electromagnet in which a conductive wire has a coil wound in a spiral shape and a magnetic core formed in the coil, wherein the conductive wire has a length substantially half of one turn of the spiral. An electromagnet in which a plurality of conductive wire pieces are connected. 13. The electromagnet according to claim 12, wherein said coil is a solenoid coil in which said conductive wires are wound in a cylindrical shape at equal intervals. 14. The electromagnet according to claim 12, wherein a half of said coil is embedded in a depression formed on a surface of the substrate. 15. The dent has a semi-cylindrical shape obtained by substantially bisecting a cylinder having a circular or elliptical cross section.
4. The electromagnet according to 4. 16. The two semi-cylindrical depressions are arranged such that the distance between two opposing surfaces of the depression is wider on the substrate surface as compared to the bottom of the depression. The electromagnet according to claim 15, wherein is an inclined surface. 17. The electromagnet according to claim 16, wherein a wiring connected to the coil is formed on a surface of the inclined surface. 18. The electromagnet according to claim 14, wherein said depression has a shape obtained by substantially bisecting a polygonal prism. 19. The depression has an inclined surface such that a distance between two opposing bottom surfaces of the polygonal pillar is wider on a surface of the substrate than a bottom portion of the depression. 18. The electromagnet according to 18. 20. The electromagnet according to claim 19, wherein a wiring connected to the coil is formed on a surface of the inclined surface. 21. A step of forming a semi-cylindrical depression on the surface of the substrate; a step of forming a plurality of discrete first conductors on the surface of the depression; and half of the depression is embedded with the depression. Forming a cylinder made of an insulator, the other half of which protrudes from the surface of the substrate; and forming a single coil on the surface of the cylinder by connecting to the first conductive wire. Forming a conductive wire of the above. 22. The step of forming the semi-cylindrical depression,
Forming a first resist with a substantially uniform thickness on the surface of the substrate; and forming a semi-cylindrical depression on the surface of the first resist by photolithography using a photomask having a gradation. 22. The coil according to claim 21, further comprising: etching the first resist and the substrate to remove the first resist while replicating a depression in the first resist surface on the substrate surface. Manufacturing method. 23. The step of forming the first conductor, the step of forming a first conductor layer on the surface of a depression formed in the substrate, and the step of forming a resist resin on the surface of the first conductor layer. Forming a second resist with a substantially uniform thickness in the recess by spraying the second resist; processing the second resist into a pattern of the first conductive wire by photolithography; 22. The method according to claim 21, further comprising the step of: etching the first conductive layer using the second resist as a mask. 24. A step of forming the cylinder, the step of forming an insulating film on the substrate including the inside of the depression, the step of flattening the surface of the insulating film, A step of forming a third resist with a thickness, and performing photolithography on the third resist using a photomask having a gradation to form a semi-cylindrical surface having a curved surface only above the depression of the substrate. Leaving the third resist; and etching the third resist and the insulating film to copy the semi-cylindrical shape of the third resist surface to the insulating film while removing the third resist. 22. The method for manufacturing a coil according to claim 21, further comprising: 25. The step of forming the second conductor, the step of forming a second conductor layer on the surface of the cylinder protruding on the substrate, and the step of forming a resist on the surface of the second conductor layer. Forming a fourth resist with a substantially uniform thickness by spraying a resin; processing the fourth resist into a pattern of the second conductive wire by photolithography; and forming the fourth resist. 22. The method of manufacturing a coil according to claim 21, further comprising the step of: etching the second conductor layer using a mask as a mask. 26. The step of forming the semi-cylindrical depression,
22. The method according to claim 21, further comprising the step of making the two opposing surfaces of the depression inclined so that the distance between the two opposing surfaces of the depression is wider on the substrate surface compared to the bottom of the depression.
A method for manufacturing the coil described in the above. 27. The method of manufacturing a coil according to claim 26, wherein the step of forming the first conductive wire includes the step of forming a first wiring connected to the coil on the surface of the inclined surface. 28. The step of forming the cylinder, wherein the distance between two opposing surfaces of the cylinder is wider on the substrate surface than at the top of the cylinder protruding from the substrate surface. 22. The method for manufacturing a coil according to claim 21, further comprising the step of making the two opposing surfaces inclined. 29. The coil manufacturing method according to claim 28, wherein the step of forming the second conductive wire includes the step of forming a second wiring connected to the coil on the surface of the inclined surface. 30. The method for manufacturing a coil according to claim 21, further comprising the step of forming the second conductor, forming the coil connected to the first conductor, and removing the cylinder. 31. A step of forming a depression having a shape obtained by substantially dividing a polygonal prism into two on the surface of a substrate; a step of forming a plurality of discrete first conductive wires on the surface of the depression; Forming a polygonal prism made of an insulator, the other half of which protrudes from the surface of the substrate; and forming a single coil on the surface of the polygonal prism by connecting with the first conductive wire. Forming a plurality of discrete second conductive wires. 32. A step of forming a semi-cylindrical depression on the surface of the substrate; a step of forming a plurality of discrete first conductors on the surface of the depression; and a step of forming the first conductor on the surface of the depression. Forming a first insulating film that covers the substrate, forming a cylinder made of a magnetic material, half of which is embedded in the recess, and the other half of which projects to the substrate surface; Forming a second insulating film continuous with the first insulating film; forming a single coil on the surface of the second insulating film by connecting to the first conductive wire; Forming a plurality of second conductive wires. 33. The step of forming the semi-cylindrical depression,
Forming a first resist with a substantially uniform thickness on the surface of the substrate; and forming a semi-cylindrical depression on the surface of the first resist by photolithography using a photomask having a gradation. 33. The electromagnet according to claim 32, further comprising: etching the first resist and the substrate to remove the first resist while replicating a depression in the surface of the first resist on the surface of the substrate. Manufacturing method. 34. The step of forming the first conductive wire includes forming a first conductor layer on a surface of a depression formed in the substrate; and forming a resist resin on the surface of the first conductor layer. Forming a second resist with a substantially uniform thickness in the recess by spraying the second resist; processing the second resist into a pattern of the first conductive wire by photolithography; 33. The method according to claim 32, further comprising the step of: etching the first conductive layer using the second resist as a mask. 35. The step of forming the cylinder, the step of forming a magnetic layer on the substrate including the inside of the depression, the step of flattening the surface of the magnetic layer, A step of forming a third resist with a substantially uniform thickness; and performing photolithography on the third resist using a photomask having a gradation, and forming a half-surface having a curved surface only above the depression of the substrate. Leaving the third resist in a cylindrical shape, etching the third resist and the magnetic layer, and removing the third resist while changing the semi-cylindrical shape of the surface of the third resist to 33. The method for producing an electromagnet according to claim 32, further comprising a step of replicating the electromagnet on a magnetic layer. 36. A step of forming the second conductor, the step of forming a second conductor layer on the surface of the second insulating film, and the step of forming a resist resin on the surface of the second conductor layer. Forming a fourth resist with a substantially uniform thickness by spraying; processing the fourth resist into a pattern of the second conductive wire by photolithography; and masking the fourth resist. 33. The method according to claim 32, further comprising: etching the second conductor layer. 37. The step of forming the semi-cylindrical depression,
33. The method of claim 32, further comprising the step of making the two opposing surfaces of the depression inclined so that the distance between the two opposing surfaces of the depression is wider on the substrate surface than the bottom of the depression.
A method for producing the electromagnet according to the above. 38. The method for manufacturing an electromagnet according to claim 37, wherein the step of forming the first conductive wire includes the step of forming a first wiring connected to the coil on the surface of the inclined surface. 39. The step of forming the cylinder, wherein the distance between two opposing surfaces of the cylinder is wider on the surface of the substrate than at the top of the cylinder protruding from the surface of the substrate. 33. The method for manufacturing an electromagnet according to claim 32, further comprising the step of: setting two opposing surfaces to be inclined surfaces. 40. The method of manufacturing an electromagnet according to claim 39, wherein the step of forming the second conductive wire includes the step of forming a second wiring connected to the coil on the surface of the inclined surface. 41. A step of forming a depression having a shape obtained by substantially dividing a polygonal prism into two on the surface of a substrate; a step of forming a plurality of discrete first conductive wires on the surface of the depression; Forming a first insulating film covering the first conductive wire; and forming a polygonal prism made of a magnetic material in which half is embedded in the recess and the other half projects to the substrate surface. And a second continuous with the first insulating film on the surface of the polygonal prism.
Forming a plurality of discrete second conductors on the surface of the second insulation film, the plurality of discrete second conductors being connected to the first conductor to form one coil. Of manufacturing an electromagnet having the same.