JP2023044463A - Insulation device - Google Patents

Abstract

To provide an insulation device that can improve life.SOLUTION: An insulation device includes an insulating film, a first coil provided inside the insulating film, and a second coil provided inside the insulating film and positioned above the first coil, and a gap is formed in the insulating film outside the second coil when viewed in a first direction from the first coil to the second coil.SELECTED DRAWING: Figure 2

Description

Embodiments of the present invention relate to isolation devices.

Isolation devices use changes in magnetic or electric fields to transmit signals while interrupting current flow. There is a need to improve the life of this insulating device.

WO2014/112179

SUMMARY OF THE INVENTION The problem to be solved by the present invention is to provide an insulating device with improved life.

An insulation device according to an embodiment includes an insulation film, a first coil provided inside the insulation film, and a second coil provided inside the insulation film and positioned above the first coil. Prepare. A gap is formed in the insulating film outside the second coil when viewed in a first direction from the first coil to the second coil.

It is a top view showing the insulation device concerning a 1st embodiment. FIG. 2 is a cross-sectional view of the insulation device in FIG. 1 as viewed in the direction of arrows AA; FIG. 4 is an explanatory diagram showing an example of forming voids in an insulating layer; 3 is an explanatory diagram showing an example of the distance between the gap and the second coil in FIG. 2 and the stress state around the gap; FIG. FIG. 3 is a cross-sectional view similar to FIG. 2 depicting an isolation device according to a second embodiment; FIG. 3 is a cross-sectional view similar to FIG. 2 depicting an isolation device according to a third embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.
The drawings are schematic or conceptual, and the relationship between the thickness and width of each portion, the size ratio between portions, and the like are not necessarily the same as the actual ones. Even when the same parts are shown, the dimensions and ratios may be different depending on the drawing.
In the specification and drawings of the present application, elements similar to those already described are denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate.

FIG. 1 is a plan view showing the insulating device according to the first embodiment. FIG.
FIG. 2 is a cross-sectional view of the insulation device in FIG. 1 as viewed in the direction of arrows AA.

The isolation device 100 is called, for example, a digital isolator, a galvanic isolator, or a galvanic isolation element. As shown in FIGS. 1 and 2, the isolation device 100 comprises a first circuit 1, a second circuit 2, a substrate 5, a first coil 11, a second coil 12, an insulating film 20, and a conductor 50. . The insulating film 20 is provided on the substrate 5 . The first coil 11 is provided inside the insulating film 20 . The second coil 12 is provided inside the insulating film 20 and positioned above the first coil 11 . The conductor 50 is positioned around the first and second coils 11 and 12 and provided inside the insulating film 20 .

The insulating film 20 includes a first insulating portion 21 in which the first coil 11 is provided, a second insulating portion 22 in which the second coil 12 is provided, the first insulating portion 21 and the second insulating portion 22 . and an insulating layer 23 positioned between. The insulating film 20 includes a third insulating portion 24 positioned between the first insulating portion 21 and the insulating layer 23, a fourth insulating portion 25 positioned between the insulating layer 23 and the second insulating portion 22, and a third insulating portion 25 positioned between the insulating layer 23 and the second insulating portion 22. It has fifth to seventh insulating portions 26 to 28 positioned above the second insulating portion 22 . As shown in FIG. 2, the insulating film 20 has a first insulating portion 21, a third insulating portion 24, an insulating layer 23, a fourth insulating portion 25, a second insulating portion 22, and a fifth insulating portion from the bottom in the Z direction. 26, a sixth insulating portion 27, and a seventh insulating portion 28 are laminated in this order. Note that the fifth to seventh insulating portions 26 to 28 are omitted in FIG.

In the description of the embodiment, an XYZ orthogonal coordinate system is used. The direction from the first coil 11 to the second coil 12 is defined as the Z direction (first direction). Two directions which are perpendicular to the Z direction and which are mutually orthogonal are defined as an X direction (second direction) and a Y direction (third direction). For the sake of explanation, the direction from the first coil 11 to the second coil 12 is called "up", and the opposite direction is called "down". These directions are based on the relative positional relationship between the first coil 11 and the second coil 12, and are irrelevant to the direction of gravity.

As shown in FIG. 2 , the first insulating section 21 is provided on the substrate 5 . The first coil 11 is provided inside the first insulating portion 21 . The third insulating portion 24 is provided on the first insulating portion 21 . The third insulating portion 24 is provided between the first coil 11 and the insulating layer 23 . The third insulating portion 24 is in contact with the first coil 11 .

The insulating layer 23 is provided on the first coil 11 and the first insulating portion 21 via the third insulating portion 24 . The insulating layer 23 has multiple layers laminated along the first direction. In this example, the insulating layer 23 has a first layer 23a and a second layer 23b located on the first layer 23a. In the first direction, the second layer 23b is thicker than the first layer. The insulating layer 23 may be one layer, or three or more layers. The second coil 12 is provided on the insulating layer 23 (second layer 23b). That is, the insulating layer 23 is positioned between the first coil 11 and the second coil 12 .

The fourth insulating portion 25 is provided on the insulating layer 23 . The fourth insulating portion 25 is provided between the insulating layer 23 and the second insulating portion 22 in the Z direction (first direction). The fourth insulating portion 25 is positioned around the second coil 12 along the XY plane. “Around the second coil 12 ” means a region including the outside and inside of the second coil 12 . That is, at least part of the second coil 12 is provided inside the fourth insulating portion 25 . “Outside the second coil 12 ” means a region radially outside the outermost conductor wire of the wound second coil 12 . On the other hand, "inside the second coil 12" means a region radially inside the outer edge of the conductor positioned on the outermost side of the wound second coil 12, and the wound conductor is arranged. It means the area where The fourth insulating portion 25 is in contact with the second coil 12 . The relative permittivity of the material used for the fourth insulating portion 25 is higher than the relative permittivity of the material used for the insulating layer 23 .

The second insulating portion 22 is provided on the fourth insulating portion 25 . The second insulating portion 22 is provided around the second coil 12 along the XY plane perpendicular to the Z direction. That is, the second coil 12 is provided inside the second insulating portion 22 . The second coil 12 penetrates the fourth insulating portion 25 and the second insulating portion 22 in the Z direction.

In the examples shown in FIGS. 1 and 2, the first coil 11 and the second coil 12 are formed in a circular spiral shape along the XY plane. In addition, the first coil 11 and the second coil 12 are not limited to the circular spiral shape, and may be formed in, for example, a rectangular spiral shape. The first coil 11 and the second coil 12 face each other in the Z direction. At least part of the second coil 12 is aligned with at least part of the first coil 11 in the Z direction.

The fifth insulating portion 26 is provided on the second insulating portion 22 and the second coil 12 . The fifth insulating portion 26 is in contact with the second coil 12, for example. The sixth insulating portion 27 is provided on the fifth insulating portion 26 . The seventh insulating portion 28 is provided on the sixth insulating portion 27 . The sixth insulating portion 27 and the seventh insulating portion 28 are provided with a pad 62 connected to the second electrode 12 and a pad 66 connected to a conductor 50 which will be described later. The pad 62 is connected to the second circuit 2 via the wiring 63 . The pads 66 are connected to a conductive member (not shown) via wiring 67 .

A conductor 50 is provided around the first coil 11 and the second coil 12 along the XY plane. An electrical conductor 50 is connected to 11, for example, the first coil. The conductor 50 includes a first conductive portion 51 , a second conductive portion 52 and a third conductive portion 53 . The first conductive portion 51 is located inside the first insulating portion 21 and provided around the first coil 11 . When viewed from above, the shape of the first conductive portion 51 is, for example, an annular shape. The first conductive portion 51 is connected to, for example, the first coil 11 .

The second conductive portion 52 is provided on part of the first conductive portion 51 . Each second conductive portion 52 has a columnar shape with the axial direction in the Z direction, for example, a quadrangular columnar shape. A plurality of second conductive portions 52 are provided along the first conductive portion 51 . That is, the plurality of second conductive portions 52 are intermittently spaced apart from each other along the annular first conductive portion 51 . The second conductive portion 52 is positioned in the third insulating portion 24 and the insulating layer 23 and extends in the vertical direction (first direction).

The third conductive portion 53 is provided on the plurality of second conductive portions 52 . The third conductive portion 53 is located inside the fourth insulating portion 25 and inside the second insulating portion 22 and around the second coil 12 . When viewed from above, the shape of the third conductive portion 53 is, for example, the same annular shape as the first conductive portion 51 . A fifth insulating portion 26 is provided on the third conductive portion 53 .

In the example shown in FIG. 1 , one end of the first coil 11 (one end of the coil) is electrically connected to the first circuit 1 via the wiring 60 . The other end of the first coil 11 (the other end of the coil) is electrically connected to the first circuit 1 via wiring 61 .

One end of the second coil 12 (one end of the coil) is electrically connected to the second circuit 2 via the pad 62 and the wiring 63 . The other end of the second coil 12 (the other end of the coil) is electrically connected to the second circuit 2 via the pad 64 and the wiring 65 . For example, pad 62 is provided on one end of second coil 12 . A pad 64 is provided on the other end of the second coil 12 . The Z-direction position of the pad 62 and the Z-direction position of the pad 64 may be the same as the Z-direction position of the second coil 12 . Pads 62 and 64 may be integrally formed with second coil 12 .

As shown in FIG. 2, pads 66 are provided on the conductors 50 . The conductor 50 is electrically connected to a conductive member (not shown) via a pad 66 and wiring 67 . For example, conductor 50 and substrate 5 are connected to a reference potential. The reference potential is, for example, ground potential. Since the conductor 50 is connected to the reference potential, it is possible to prevent the conductor 50 from becoming a floating potential. Thereby, leakage of the magnetic field generated from the first coil 11 and the second coil 12 can be suppressed, and an external magnetic field can be suppressed from reaching the first coil 11 and the second coil 12 .

Also, the first circuit 1 may be provided on the substrate 5 . In this case, since the conductor 50 is provided on the first circuit 1, the first circuit 1 is shielded by the conductor 50 from electromagnetic waves directed toward the first circuit 1 from the outside of the substrate 5 and the conductor 50. be done. As a result, the operation of the first circuit 1 can be made more stable.

Either one of the first circuit 1 and the second circuit 2 is used as a transmission circuit. The other of the first circuit 1 and the second circuit 2 is used as a transmission/reception circuit. Here, the case where the first circuit 1 is a transmitting/receiving circuit and the second circuit 2 is a transmitting/receiving circuit will be described.

The first circuit 1 sends a signal (current) having a waveform suitable for transmission to the first coil 11 . When a current flows through the first coil 11 , a magnetic field is generated that passes inside the spiral first coil 11 . At least part of the first coil 11 is aligned with at least part of the second coil 12 in the Z direction. Part of the generated magnetic lines of force pass through the inside of the second coil 12 . A change in the magnetic field inside the second coil 12 causes an induced electromotive force in the second coil 12 , causing a current to flow through the second coil 12 . The second circuit 2 detects the current flowing through the second coil 12 and generates a signal according to the detection result. As a result, a signal is transmitted between the first coil 11 and the second coil 12 while the current is interrupted (insulated).

Next, an example of materials for each component of the insulation device 100 will be described.
The first coil 11, the second coil 12, and the conductor 50 contain metal, for example. The first coil 11, the second coil 12, and the conductor 50 contain at least one metal selected from the group consisting of copper and aluminum, for example. In order to suppress heat generation in the first coil 11 and the second coil 12 during signal transmission, the electric resistance of these coils is preferably low. From the viewpoint of reducing electrical resistance, first coil 11 and second coil 12 preferably contain copper.

The first insulating portion 21, the insulating layer 23, the second insulating portion 22, and the sixth insulating portion 27 contain silicon and oxygen. For example, the first insulating portion 21, the insulating layer 23, the second insulating portion 22, and the sixth insulating portion 27 contain silicon oxide. The first insulating portion 21, the insulating layer 23, the second insulating portion 22, and the sixth insulating portion 27 may further contain nitrogen. For example, the nitrogen concentration of the second layer 23b of the insulating layer 23 is higher than the nitrogen concentration of the first layer 23a.

The seventh insulating portion 28 contains an insulating resin such as polyimide or polyamide. The third insulating portion 24 and the fifth insulating portion 26 contain silicon and nitrogen. The third insulating portion 24 and the fifth insulating portion 26 contain silicon nitride, for example. Substrate 5 contains silicon and impurities. Impurities are at least one selected from the group consisting of boron, phosphorus, arsenic, and antimony.

The fourth insulating portion 25 includes a first material containing silicon and nitrogen, a second material containing aluminum and oxygen, a third material containing tantalum and oxygen, a fourth material containing hafnium and oxygen, and a fifth material containing zirconium and oxygen. a sixth material comprising strontium, titanium and oxygen; a seventh material comprising bismuth, iron and oxygen; and an eighth material comprising barium, titanium and oxygen. For example, the fourth insulating section 25 contains silicon nitride. The relative permittivity of the fourth insulating portion 25 is higher than the relative permittivity of the insulating layer 23 and higher than the relative permittivity of the second insulating portion 22 .

For example, the fourth insulating portion 25 contains silicon and nitrogen, and the insulating layer 23 and the second insulating portion 22 contain silicon, oxygen, and nitrogen. In this case, the nitrogen concentration in the fourth insulating portion 25 is higher than the nitrogen concentration in the insulating layer 23 and higher than the nitrogen concentration in the second insulating portion 22 .

Next, the void 70 formed inside the insulating film 20 will be described.

As shown in FIG. 1 , the insulating film 20 has a gap 70 formed outside the second coil 12 when viewed in the first direction from the first coil 11 to the second coil 12 . In other words, the air gap 70 is located inside the insulating film 20 and formed along the outer peripheral edge of the second coil 12 in plan view. “Outside the second coil 12 ” means a region radially outside the outermost conductor wire of the wound second coil 12 . On the other hand, "inside the second coil 12" means a region radially inside the outer edge of the conductor positioned on the outermost side of the wound second coil 12, and the wound conductor is arranged. It means the area where

The void 70 is an air layer. Air gap 70 reduces residual stress in insulating film 20 that occurs when insulating device 100 is manufactured. The air gap 70 thereby improves the life of the insulating device 100 . The size, length, and shape of the air gap 70 are set through experiments and simulations in consideration of the effect of reducing residual stress, the rigidity of the insulating device 100, and the like. The stress reduction of the insulating film 20 by the air gap 70 will be described later.

As shown in FIG. 2, voids 70 are formed in insulating layer 23 . In this example, the air gap 70 extends downward from the upper end 23b1 of the insulating layer 23 . The lower end of the gap 70 is positioned at the lower end of the insulating layer 23 . In other words, the gap 70 extends across multiple layers of the second layer 23b and the first layer 23a. In this case, the air gap 70 is formed so that the first coil 11 and the second coil 12 are not communicated with each other. For example, the air gap 70 does not contact the second coil 12 at its upper end and does not contact the first coil 11 at its lower end. Also, if the upper end of the air gap 70 is in contact with the second coil 12 , the lower end thereof is not in contact with the first coil 11 . Alternatively, if the lower end of the gap 70 is in contact with the first coil 11 , the upper end of the gap 70 is not in contact with the second coil 12 . In other words, at least one of the gap 70 and the first coil 11 and/or the gap 70 and the second coil 12 is provided with an insulating portion. Thereby, the insulation state between the first coil 11 and the second coil 12 can be stably maintained.

Also, as shown in FIG. 1, the air gap 70 surrounds the second coil 12 when viewed from the first direction. That is, the air gap 70 extends in a circular shape along the outermost conducting wire of the second coil 12 . Thereby, the residual stress in the insulating film 20 can be effectively reduced outside the first coil 11 and the second coil 12 .

A gap 70 is provided between the second coil 12 and the conductor 50 . Specifically, the air gap 70 is provided near the second coil 12 . In other words, the air gap 70 is provided closer to the second coil 12 than the intermediate position (chain line BB in FIG. 2) between the second coil 12 and the conductor 50 . Thereby, the stress remaining in the area outside the second coil 12 can be effectively reduced.

Next, a method for forming the void 70 in the insulating film 20 will be described.
FIG. 3 is an explanatory diagram showing an example of a method of forming voids in an insulating layer. FIG. 3A shows a state in which an insulating layer 23 is formed. FIG. 3(b) shows a case where a gap 70 is formed in the insulating layer 23. As shown in FIG. FIG. 3C shows a case where the fourth insulating portion 25 is formed on the insulating layer 23 and the gap 70. FIG.

First, as shown in FIG. 3A, the first insulating section 21 is formed on the substrate 5 by chemical vapor deposition (CVD). Then, recesses in which the first coil 11 and the first conductive part 51 are embedded are formed by reactive ion etching (RIE). The first coil 11 and the first conductive portion 51 are embedded in the concave portion, and then the third insulating portion 24 and the insulating layer 23 are formed on the first insulating portion 21 and the first coil 11 by CVD.

As shown in FIG. 3B, when forming the air gap 70, a resist 110 is formed on the insulating layer 23, and an opening is formed in a region where the air gap 70 is to be formed. In this state, by RIE using the resist 110 as a mask, a void 70 extending in the vertical direction can be formed in the insulating layer 23 . After that, the resist 110 is removed. Then, as shown in FIG. 3C, the fourth insulating portion 25 is formed on the insulating layer 23 and the gap 70 by CVD. At this time, the formation conditions of the fourth insulating portion 25 are controlled so that the fourth insulating portion 25 does not fill the void 70 . The fifth to seventh insulating parts 26 to 28, the second coil 12, and the second and third conductive parts 52, 53 are similarly formed by CVD and RIE. Thus, the insulating device 100 is manufactured.

In the insulating device 100 manufactured in this manner, residual stress is generated inside the insulating film 20 during the manufacturing process. For example, if this residual stress is applied to the portion of the second coil 12 where the electric field is strong, the life of the insulation device 100 may be shortened. The portion of the second coil 12 where the electric field is strong is, for example, the vicinity of the outermost conducting wire of the second coil 12 . Therefore, an air gap 70 is formed inside the insulating film 20 to reduce this residual stress.

FIG. 4 is an explanatory diagram showing an example of the distance between the gap and the second coil in FIG. 2 and the stress state around the gap. A characteristic line 81 represented by a dotted line in FIG. 4 indicates the stress state when the air gap 70 is not formed. On the other hand, a characteristic line 82 indicated by a solid line in FIG. 4 indicates the stress state when the air gap 70 is formed. Here, an example is shown in which the insulating layer 23 is silicon oxide containing nitrogen, and the nitrogen concentration of the second layer 23b is higher than that of the first layer 23a.

As represented by the characteristic line 81, a large residual stress (tensile stress) is generated in the second layer 23b of the insulating layer 23 when the void 70 is not formed. Therefore, in the insulating layer 23 , a gap 70 extending in the vertical direction is formed at a position within a horizontal distance D from the second coil 12 . The distance D is, for example, 4 μm. Further, the air gap 70 extends downward from the upper end 23b1 of the insulating layer 23 . The air gap 70 allows deformation of the insulating layer 23 due to residual stress. Thereby, as represented by the characteristic line 82, the residual stress (tensile stress) of the second layer 23b can be reduced. As a result, residual stress can be reduced in the upper portion of the insulating layer 23 where the electric field concentrates, and the life of the insulating device 100 is improved.

FIG. 5 is a cross-sectional view similar to FIG. 2 showing an isolation device according to a second embodiment.
In the first embodiment described above, the case where the air gap 70 is formed outside the second coil 12 has been described as an example. However, embodiments of the present invention are not limited to this. For example, as in the second embodiment shown in FIG. Other voids 72 may be formed. Thereby, the residual stress around the other voids 72 can be reduced.

FIG. 6 is a cross-sectional view similar to FIG. 2 showing an isolation device according to a third embodiment. FIG. 6(a) shows the case where the void is formed only in the uppermost layer of the insulating layer. FIG. 6B shows the case where the void extends above the insulating layer.
In the first embodiment described above, the case where the gap 70 is formed over a plurality of layers of the insulating layer 23 has been described as an example. However, the embodiment of the present invention is not limited to this, and the length dimension of the gap in the first direction can be arbitrarily set as in the third embodiment shown in FIG. 6, for example. As shown in FIG. 6A, the void 74 may be formed only in the uppermost layer (second layer 23b) of the insulating layer 23. As shown in FIG. Moreover, as shown in FIG. 6B, the air gap 76 may have its upper end extended to the third insulating portion 24 or the second insulating portion 22, or its lower end to the middle of the first layer 23a.

Further, in the first embodiment described above, the case where the air gap 70 surrounds the second coil 12 when viewed from the first direction has been described as an example. However, the embodiment of the present invention is not limited to this, and for example, the gaps may be divided in the circumferential direction outside the second coil 12 and formed. Also, the air gap may be formed only in a part of the outer side of the second coil 12 .

According to the embodiments described above, it is possible to realize an insulating device with improved life.

Embodiments may include the following configurations.
(Configuration 1)
an insulating film;
a first coil provided inside the insulating film;
a second coil provided inside the insulating film and positioned above the first coil;
with
The insulating device, wherein the insulating film has a gap outside the second coil when viewed in a first direction from the first coil to the second coil.
(Configuration 2)
The insulating film has an insulating layer positioned between a first insulating portion in which the first coil is provided and a second insulating portion in which the second coil is provided,
2. The insulation device of arrangement 1, wherein the void is formed in the insulation layer.
(Composition 3)
3. The insulation device of arrangement 2, wherein the air gap extends downward from the top of the insulation layer.
(Composition 4)
The insulating layer has a plurality of layers laminated along the first direction,
4. The isolation device of configuration 2 or 3, wherein the air gap extends across the multiple layers.
(Composition 5)
The insulating layer has a plurality of layers laminated along the first direction,
4. The insulating device of any one of configurations 2 or 3, wherein the air gap is formed only in the topmost layer of the insulating layer.
(Composition 6)
6. The isolation device of any one of arrangements 1-5, wherein the air gap surrounds the second coil viewed from the first direction.
(Composition 7)
7. The isolation device according to any one of configurations 1-6, wherein another air gap is formed in a portion of the insulation layer between the first coil and the second coil.
(Composition 8)
8. The isolation device according to any one of configurations 1 to 7, wherein the air gap is formed within 4 μm from the second coil.
(Composition 9)
The insulation device according to any one of configurations 1 to 8, wherein the gap is formed so that the first coil and the second coil are not communicated with each other.
(Configuration 10)
10. The isolation device according to any one of configurations 1 to 9, wherein the first coil and the second coil are formed in a circular spiral shape.
(Composition 11)
further comprising a conductor provided inside the insulating film and connected to the first coil;
11. The isolation device according to any one of configurations 1-10, wherein the air gap is provided between the second coil and the conductor.

Although some embodiments of the present invention have been illustrated above, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, changes, etc. can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof. Moreover, each of the above-described embodiments can be implemented in combination with each other.

1 first circuit 2 second circuit 5 substrate 11 first coil 12 second coil 20 insulating film 21 first insulating part 22 second insulating part 23 insulating layer 23a first layer 23b second layer 23b1 upper end 24 third insulating part 25 Fourth insulating portion 26 Fifth insulating portion 27 Sixth insulating portion 28 Seventh insulating portion 50 Conductor 51 First conductive portion 52 Second conductive portion 53 Third conductive portion 60, 61, 63, 65, 67 Wiring 62, 64 , 66 pad 70, 74, 76 air gap 72 other air gap 81, 82 characteristic line 100 isolation device 110 resist

Claims (11)

an insulating film;
a first coil provided inside the insulating film;
a second coil provided inside the insulating film and positioned above the first coil;
with
The insulating device, wherein the insulating film has a gap outside the second coil when viewed in a first direction from the first coil to the second coil. The insulating film has an insulating layer positioned between a first insulating portion in which the first coil is provided and a second insulating portion in which the second coil is provided,
2. The insulation device of claim 1, wherein said void is formed in said insulation layer. 3. The insulation device of claim 2, wherein said void extends downwardly from the top of said insulation layer. The insulating layer has a plurality of layers laminated along the first direction,
4. The isolation device of claim 2 or 3, wherein the air gap extends across the multiple layers. The insulating layer has a plurality of layers laminated along the first direction,
4. The insulation device according to claim 2 or 3, wherein the void is formed only in the uppermost layer of the insulation layer. The isolation device according to any one of claims 1 to 5, wherein said air gap surrounds said second coil viewed from said first direction. The insulation device according to any one of claims 1 to 6, wherein another gap is formed in a portion of the insulation layer between the first coil and the second coil. The insulation device according to any one of claims 1 to 7, wherein the gap is formed within 4 µm from the second coil. The insulation device according to any one of claims 1 to 8, wherein the gap is formed so that the first coil and the second coil are not communicated with each other. The insulation device according to any one of claims 1 to 9, wherein said first coil and said second coil are formed in a circular spiral shape. further comprising a conductor provided inside the insulating film and connected to the first coil;
The insulation device according to any one of claims 1 to 10, wherein the air gap is provided between the second coil and the conductor.

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