Isolator

Abstract

The isolator of the embodiment comprises: a substrate; a first planar coil disposed above the substrate along the surface of the substrate; a first insulating portion disposed on the first planar coil; a second planar coil disposed on the first insulating portion; and a metal layer disposed above the first insulating portion. The first planar coil, the second coil, and the metal layer are arranged side by side in a first direction perpendicular to the surface of the substrate. In a second direction along the surface of the substrate, a distance from a center line of the first planar coil to an outer periphery is shorter than a distance from a center line of the second planar coil to an outer periphery.

Description

[0001] Related Applications

[0002] This application claims priority based on Japanese Patent Application No. 2020-49624 (filing date: March 19, 2020), and this application incorporates the entire contents of the basic application by reference. Technical Field

[0003] Embodiments of the present invention generally relate to isolators. Background Art

[0004] The isolator transmits a signal by utilizing a change in a magnetic field or an electric field when the current is cut off. It is desired that the isolator is not easily damaged. Summary of the invention

[0005] The embodiment provides an isolator capable of reducing the possibility of damage.

[0006] The isolator of the embodiment comprises: a substrate; a first planar coil provided above the substrate along the surface of the substrate; a first insulating portion provided on the first planar coil; a second planar coil provided on the first insulating portion; and a metal layer provided above the first insulating portion. The first planar coil, the second coil, and the metal layer are arranged in a first direction perpendicular to the surface of the substrate. In a second direction along the surface of the substrate, a distance from a center to an outer periphery of the first planar coil is shorter than a distance from a center to an outer periphery of the second planar coil. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a schematic plan view showing the isolator according to the first embodiment.

[0008] Figure 2 It is a schematic cross-sectional view showing the isolator according to the first embodiment.

[0009] Figure 3 (a) and (b) are schematic diagrams showing the characteristics of the isolator according to the first embodiment.

[0010] Figure 4 (a) to (c) are schematic diagrams showing the characteristics of the isolator according to the first embodiment.

[0011] Figure 5 (a) and (b) are schematic cross-sectional views showing the characteristics of the isolator according to the first embodiment.

[0012] Figure 6 It is a schematic cross-sectional view showing an isolator according to a modified example of the first embodiment.

[0013] Figure 7 It is a schematic cross-sectional view showing an isolator according to a modified example of the first embodiment.

[0014] Figure 8 It is a schematic cross-sectional view showing an isolator according to a modified example of the first embodiment.

[0015] Fig. 9 It is a schematic cross-sectional view showing an isolator according to a modified example of the first embodiment.

[0016] Fig.10 It is a schematic cross-sectional view showing an isolator according to a second embodiment.

[0017] Fig.11 (a) and (b) are schematic diagrams showing the characteristics of the isolator according to the second embodiment.

[0018] Fig.12 It is a schematic cross-sectional view showing an isolator according to a modified example of the second embodiment.

[0019] Fig.13 It is a top view showing an isolator according to a third embodiment.

[0020] Fig.14 It is a schematic diagram showing a cross-sectional structure of an isolator according to a third embodiment.

[0021] Fig.15 It is a plan view showing an isolator according to a first modified example of the third embodiment.

[0022] Fig.16 yes Fig.15 A1-A2 cross-sectional view.

[0023] Fig.17 yes Fig.15 B1-B2 cross-sectional view.

[0024] Fig.18 It is a schematic diagram showing a cross-sectional structure of an isolator according to a first modified example of the third embodiment.

[0025] Fig.19 It is a plan view showing an isolator according to a second modified example of the third embodiment.

[0026] Fig. 20 It is a schematic diagram showing a cross-sectional structure of an isolator according to a second modified example of the third embodiment.

[0027] Fig.21 It is a schematic diagram showing an isolator according to a third modified example of the third embodiment.

[0028] Fig. 22 It is a perspective view showing a package according to a fourth embodiment.

[0029] Fig.23 It is a schematic diagram showing a cross-sectional structure of a package according to a fourth embodiment. DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0031] The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of the size between parts, etc. are not necessarily the same as the actual ones. Even when the same part is shown, the size and ratio may be shown differently depending on the drawings.

[0032] (First Embodiment)

[0033] Figure 1 It is a top view showing the isolator according to the first embodiment.

[0034] Figure 2 yes Figure 1 A1-A2 cross-sectional view.

[0035] The first embodiment relates to a device called, for example, a digital isolator, a galvanic isolator, or a galvanic insulating element. Figure 1 and Figure 2 As shown, the isolator 100 of the first embodiment includes a first circuit 1, a second circuit 2, a substrate 5, a first planar coil 11, a second planar coil 12, a first insulating portion 21, a second insulating portion 22, an insulating portion 28, an insulating portion 29, a dielectric portion 31, a dielectric portion 41, a dielectric portion 42, a conductor 50, a metal layer 62, and a wiring layer 70. Figure 1 Insulating portions 28 and 29 are omitted.

[0036] The first planar coil 11, the second planar coil 12 and the metal layer 62 have, for example, a circular outer periphery, and are arranged, for example, in a common center line CL in a direction (Z direction) perpendicular to the surface of the substrate 5. In addition, the outer periphery of the first planar coil 11, the second planar coil 12 and the metal layer 62 is not limited to a circle, and may be, for example, a polygon, an ellipse, etc.

[0037] In the description of the embodiment, an XYZ orthogonal coordinate system is used. The direction from the first planar coil 11 toward the second planar coil 12 is set as the Z direction (first direction). Two directions perpendicular to the Z direction and along the surface of the substrate 5 and orthogonal to each other are set as the X direction (second direction) and the Y direction (third direction). In addition, for the sake of explanation, the direction from the first planar coil 11 toward the second planar coil 12 is called "up", and the opposite direction is called "down". These directions are based on the relative positional relationship between the first planar coil 11 and the second planar coil 12, and have nothing to do with the direction of gravity.

[0038] like Figure 2 As shown, the insulating portion 20 is provided on the substrate 5 via the wiring layer 70. The first planar coil 11 is provided in the insulating portion 20. The first insulating portion 21 is provided on the first planar coil 11 and the insulating portion 20. The second planar coil 12 is provided on the first insulating portion 21. The second insulating portion 22 is provided around the second planar coil 12 along the XY plane (first plane) perpendicular to the Z direction. The second insulating portion 22 is in contact with the second planar coil 12.

[0039] exist Figure 1 and Figure 2 In the example shown, the first planar coil 11 and the second planar coil 12 are arranged in a spiral shape along the XY plane. The first planar coil 11 and the second planar coil 12 are opposed to each other in the Z direction. At least a portion of the second planar coil 12 is aligned with at least a portion of the first planar coil 11 in the Z direction.

[0040] The dielectric portion 31 is provided between the first insulating portion 21 and the second insulating portion 22 in the Z direction. At least a portion of the dielectric portion 31 is located around the second planar coil 12 along the XY plane. The dielectric portion 31 is in contact with the second planar coil 12 .

[0041] The dielectric portion 41 is provided on the second planar coil 12 and the second insulating portion 22. For example, the dielectric portion 41 is in contact with the second planar coil 12 and the second insulating portion 22.

[0042] The conductor 50 is arranged around the first planar coil 11 and the second planar coil 12 along the first surface. Specifically, 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 arranged around the first planar coil 11 along the XY plane. The second conductive portion 52 is arranged on a portion of the first conductive portion 51. A plurality of second conductive portions 52 are arranged along the first conductive portion 51. The third conductive portion 53 is arranged on a plurality of second conductive portions 52. The third conductive portion 53 is located around the second planar coil 12 along the XY plane.

[0043] exist Figure 1 In the example shown, one end of the first planar 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 planar coil 11 (the other end of the coil) is electrically connected to the conductor 50 via the wiring 73 .

[0044] One end of the second planar coil 12 (one end of the coil) is electrically connected to the second circuit 2 via the metal layer 62 and the wiring 63. The other end of the second planar coil 12 (the other end of the coil) is electrically connected to the second circuit 2 via the metal layer 64 and the wiring 65. For example, the metal layer 62 is disposed on one end of the second planar coil 12. The metal layer 64 is disposed on the other end of the second planar coil 12. The position of the metal layer 62 in the Z direction and the position of the metal layer 64 in the Z direction may also be the same as the position of the second planar coil 12 in the Z direction. The metal layers 62 and 64 may also be formed integrally with the second planar coil 12.

[0045] like Figure 2 As shown in the figure, a metal layer 66 is provided on the conductor 50. The conductor 50 is electrically connected to a conductive member (not shown) via the metal layer 66 and the wiring 67. For example, the conductor 50 and the substrate 5 are connected to a reference potential. The reference potential is, for example, a ground potential. The conductor 50 is connected to the reference potential, which can prevent the conductor 50 from becoming a floating potential. As a result, the possibility of unexpected insulation breakdown between the conductor 50 and each planar coil due to the change in the potential of the conductor 50 can be reduced.

[0046] In addition, a circuit electrically connected to the first planar coil 11 may be provided on the substrate 5. The first circuit 1 is, for example, a part of a circuit provided on the substrate 5. In this case, the conductor 50 is provided on the substrate 5 via the wiring layer 70, and the circuit is provided between the substrate 5 and the wiring layer 70, so that the circuit of the substrate 5 is shielded by the conductor 50 from electromagnetic waves from the outside of the substrate 5 and the conductor 50 toward the substrate 5. As a result, the operation of the circuit can be further stabilized. The wiring layer 70 includes a wiring 73 that electrically connects the first planar coil 11 to the conductor 50.

[0047] The insulating portion 28 is provided around the metal layers 62 and 66 along the XY plane. The insulating portion 29 is provided on the insulating portion 28 .

[0048] 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 reception circuit. Here, a case where the first circuit 1 is a transmission circuit and the second circuit 2 is a reception circuit is described.

[0049] The first circuit 1 sends a signal (current) of a waveform suitable for transmission to the first planar coil 11. When the current flows through the first planar coil 11, a magnetic field passing through the inner side of the spiral first planar coil 11 is generated. At least a portion of the first planar coil 11 is parallel to at least a portion of the second planar coil 12 in the Z direction. A portion of the generated magnetic lines of force pass through the inner side of the second planar coil 12. Due to the change in the magnetic field inside the second planar coil 12, an induced electromotive force is generated in the second planar coil 12, and a current flows in the second planar coil 12. The second circuit 2 detects the current flowing through the second planar coil 12 and generates a signal corresponding to the detection result. Thus, a signal is transmitted between the first planar coil 11 and the second planar coil 12 in a state where the current is cut off (insulated).

[0050] An example of the material of each component of the isolator 100 will be described.

[0051] The first planar coil 11, the second planar coil 12, and the conductor 50 include, for example, metal. The first planar coil 11, the second planar coil 12, and the conductor 50 include, for example, at least one metal selected from the group consisting of copper and aluminum. In order to suppress the heat generation in the first planar coil 11 and the second planar coil 12 when transmitting a signal, it is preferred that the resistance of these planar coils is low. From the viewpoint of reducing the resistance, the first planar coil 11 and the second planar coil 12 preferably include copper.

[0052] The insulating portion 20, the first insulating portion 21, the second insulating portion 22, and the insulating portion 28 contain silicon and oxygen. For example, the insulating portion 20, the first insulating portion 21, the second insulating portion 22, and the insulating portion 28 contain silicon oxide. The insulating portion 20, the first insulating portion 21, the second insulating portion 22, and the insulating portion 28 may further contain nitrogen.

[0053] The insulating portion 29 is made of insulating resin such as polyimide or polyamide.

[0054] The dielectric portion 31 includes, for example, silicon and nitrogen.

[0055] The dielectric portions 41 and 42 include, for example, silicon and nitrogen. For example, the dielectric portions 41 and 42 include silicon nitride.

[0056] The substrate 5 contains silicon and impurities. The impurities are at least one selected from the group consisting of boron, phosphorus, arsenic, and antimony.

[0057] The second planar coil 12 may also include a first metal layer 12a and a second metal layer 12b. The second metal layer 12b is provided between the first metal layer 12a and the first insulating portion 21, between the first metal layer 12a and the dielectric portion 31, and between the first metal layer 12a and the second insulating portion 22. The first planar coil 11 may also include a third metal layer 11c and a fourth metal layer 11d. The fourth metal layer 11d is provided between the third metal layer 11c and the insulating portion 20. The first metal layer 12a and the third metal layer 11c include copper. The second metal layer 12b and the fourth metal layer 11d include tantalum. The second metal layer 12b and the fourth metal layer 11d may also include a laminated film of tantalum and tantalum nitride. By providing the second metal layer 12b and the fourth metal layer 11d, it is possible to suppress the diffusion of the metal material contained in the first metal layer 12a and the third metal layer 11c into each insulating portion.

[0058] The first conductive portion 51 may also include metal layers 51a and 51b. The metal layer 51b is provided between the metal layer 51a and the insulating portion 20. The second conductive portion 52 may also include metal layers 52a and 52b. The metal layer 52b is provided between the metal layer 52a and the first insulating portion 21, and between the metal layer 52a and the first conductive portion 51. The third conductive portion 53 may also include metal layers 53a and 53b. The metal layer 53b is provided between the metal layer 53a and the second insulating portion 22, between the metal layer 53a and the dielectric portion 31, and between the metal layer 53a and the second conductive portion 52. The metal layers 51a to 53a include copper. The metal layers 51b to 53b include tantalum. The metal layers 51b to 53b may also include a stacked film of tantalum and tantalum nitride. By providing the metal layers 51b to 53b, it is possible to suppress the diffusion of the metal material included in the metal layers 51a to 53a into each insulating portion.

[0059] In the isolator 100 of the embodiment, when a signal is transmitted between the first planar coil 11 and the second planar coil 12, a positive voltage relative to the first planar coil 11 is applied to the second planar coil 12. As a result, a potential difference is generated between the first planar coil 11 and the second planar coil 12 and between the conductor 50 and the second planar coil 12. At this time, an electric field concentration sometimes occurs at the lower end of the outer peripheral side of the second planar coil 12, causing insulation breakdown between the first planar coil 11 and the second planar coil 12. Therefore, it is desirable to reduce the vicinity of the lower end LE1 (see Figure 3 The electric field strength of (a)) is reduced to avoid damage to the isolator 100.

[0060] In the isolator 100, as Figure 2As shown, the distance R1 from the center line of the first planar coil 11 to the periphery in the X direction is shorter than the distance R2 from the center to the periphery of the second planar coil 12. In addition, the distance R3 from the center to the inner periphery of the first planar coil 11 is shorter than the distance R4 from the center to the inner periphery of the second planar coil 12. The distance R5 from the center to the periphery of the metal layer 62 is shorter than the distance R4 from the center to the inner periphery of the second planar coil 12 (see Figure 1 ).

[0061] The number of turns of the first planar coil 11 is the same as the number of turns of the second planar coil 12. In this example, the first planar coil 11 is provided with a smaller outer diameter than the second planar coil 12.

[0062] Figures 3 to 5 It is a schematic diagram showing the characteristics of the isolator 100 according to the first embodiment.

[0063] Figure 3 (a) Figure 4 (a) Figure 4 (b) Figure 5 (a) and Figure 5 (b) is a schematic cross-sectional view showing the electric field intensity distribution between the first planar coil 11 and the second planar coil 12 .

[0064] Figure 3 (a) shows the equipotential surfaces between the first planar coil 11 and the second planar coil 12. The electric field intensity is high in the narrow interval between the equipotential surfaces, and the wider the interval between the equipotential surfaces, the lower the electric field intensity. The same is true for the electric field distribution in the following figures.

[0065] like Figure 3 As shown in (a), the electric field intensity increases at the upper end UE1 of the outer periphery of the first planar coil 11 and the lower end LE1 of the outer periphery of the second planar coil 12. The electric field intensity at the lower end LE1 of the second planar coil 12 is higher than the electric field intensity at the upper end UE1 of the first planar coil 11.

[0066] Figure 3 (b) is a graph showing the electric field strength at the lower end LE1 on the outer periphery of the second planar coil 12. The vertical axis is the electric field strength at the lower end LE1. The horizontal axis is the difference ΔR1 (= R2-R1) between the distance R2 from the center to the periphery of the second planar coil 12 and the distance R1 from the center to the periphery of the first planar coil 11.

[0067] like Figure 3As shown in (b), the larger ΔR1 is, the lower the electric field strength at the lower end LE1 is. That is, the larger ΔR1 is, the more the electric field concentration at the lower end LE1 of the second planar coil 12 and the upper end UE1 of the first planar coil 11 can be alleviated, thereby avoiding insulation breakdown between the first planar coil 11 and the second planar coil 12.

[0068] Figure 4 (a) and (b) are cross-sectional views showing the electric field distribution on the inner circumference side of the first planar coil 11 and the second planar coil 12. The inner circumference side end of the first planar coil 11 is arranged closer to the center line CL than the inner circumference side end of the second planar coil 12 (see Figure 2 )’s location.

[0069] exist Figure 4 In the example shown in (a), electric field concentration occurs at the lower end LE2 on the inner circumference side of the second planar coil 12. Figure 4 In the example shown in (b), the metal layer 62 is provided at the center of the second planar coil 12 (see Figure 1 ) The metal layer 62 is provided, for example, at a position higher than the level of the upper surface of the second planar coil 12 in the Y direction.

[0070] Figure 4 (c) is a graph showing the electric field strength at the lower end LE2 on the inner circumference side of the second planar coil 12. The vertical axis is the electric field strength at the lower end LE2. The horizontal axis is the difference ΔR2 (= R4-R3) between the distance R4 from the center of the second planar coil 12 to the inner circumference and the distance R3 from the center of the first planar coil 11 to the inner circumference (refer to Figure 2 ).

[0071] Figure 4 (c) shows characteristic A when the metal layer 62 is not configured and characteristic B when the metal layer 62 is configured. In characteristic A, as ΔR2 increases, the electric field intensity at the lower end LE2 increases. In contrast, in characteristic B, the electric field intensity at the lower end LE2 does not increase. Figure 3 The electric field strength at the lower end LE1 of (a) is as follows Figure 3 (b) is reduced.

[0072] By disposing the metal layer 62 in this manner, the electric field concentration at the lower end LE on the inner peripheral side of the second planar coil 12 can be alleviated, and insulation breakdown between the first planar coil 11 and the second planar coil 12 can be avoided.

[0073] Figure 5 (a) and (b) are cross-sectional views showing other electric field distributions on the outer peripheral sides of the first planar coil 11 and the second planar coil.

[0074] exist Figure 5In the example shown in (a), the interval T1 between the first planar coil 11 and the second planar coil 12 in the Z direction is wider than the interval T2 between the substrate 5 and the first planar coil 11 in the Z direction. Figure 5 In the example shown in (b), the interval T1 is narrower than the interval T2.

[0075] exist Figure 5 In the example shown in (b), an electric field distribution such that an equipotential surface spreads occurs between the substrate 5 and the outer peripheral end of the first planar coil 11. As a result, the electric field intensity at the upper end UE2 on the inner peripheral side of the first planar coil 11 increases.

[0076] In order to avoid insulation breakdown between the first planar coil 11 and the second planar coil 12 , the interval T1 between the first planar coil 11 and the second planar coil 12 in the Z direction is preferably larger than the interval T2 between the substrate 5 and the first planar coil 11 in the Z direction.

[0077] Figure 6 to Figure 8 Schematic cross-sectional views respectively show isolators 110 , 120 , and 130 according to modified examples of the first embodiment.

[0078] exist Figure 6 In the isolator 110 shown, the distance R5 from the center to the periphery of the metal layer 62 in the X direction is shorter than the distance R4 from the center to the inner periphery of the second planar coil 12, and the metal layer 62 is arranged in the space surrounded by the inner periphery of the second planar coil 12. The metal layer 62 is electrically connected to the second planar coil 12 at a portion not shown.

[0079] At least a portion of the metal layer 62 faces the inner periphery of the second planar coil 12 in the direction along the surface of the substrate 5 (eg, the X direction). This can further reduce the lower end LE2 (see Figure 4 (b) The electric field strength of.

[0080] The metal layer 62 includes, for example, a metal layer 62A and a metal layer 62B. The metal layer 62A is disposed at a position opposite to the inner periphery of the second planar coil 12. The metal layer 62 includes metal layers 62a and 62b. The metal layer 62b is disposed, for example, in contact with the second insulating portion 22 and the dielectric portion 31. The metal layer 62b is disposed between the second insulating portion 22 and the metal layer 62a, and between the dielectric portion 31 and the metal layer 62a. The metal layer 62a includes the same material as the metal layer 12a of the second planar coil 12, and the metal layer 62b includes the same material as the metal layer 12b of the second planar coil 12.

[0081] The metal layer 62B is provided on the metal layer 62A and is electrically connected to the metal layer 62A. The wiring 63 is bonded to the metal layer 62B, for example.

[0082] exist Figure 7 In the isolator 120 shown, the distance R1 from the center to the periphery of the first planar coil 11 is shorter than the distance R2 from the center to the periphery of the second planar coil 12, and the distance R3 from the center to the inner periphery of the first planar coil 11 is longer than the distance R4 from the center to the inner periphery of the second planar coil 12.

[0083] That is, the interval (R1-R3) between the outer periphery and the inner periphery of the first planar coil 11 is set to be narrower than the interval (R2-R4) between the outer periphery and the inner periphery of the second planar coil 12. As a result, the electric field intensity at the lower end LE2 on the inner periphery side of the second planar coil 12 can be reduced (refer to Figure 3 In addition, by configuring the metal layer 62, the electric field strength at the lower end LE2 can be further reduced (see Figure 4 (b)).

[0084] In this example, the number of turns of the first planar coil 11 is the same as the number of turns of the second planar coil 12. For example, by reducing at least one of the width of the winding of the first planar coil 11 in the X direction and the width of the space between the windings, the interval (R1-R3) between the outer periphery and the inner periphery of the first planar coil 11 can be reduced.

[0085] By making the number of turns of the first planar coil 11 and the number of turns of the second planar coil 12 the same, it is possible to easily design the magnetic coupling between the first planar coil 11 and the second planar coil 12 .

[0086] exist Figure 8 In the isolator 130 shown, the metal layer 62 is located at a level higher than the upper surface of the second planar coil 12 in the Z direction. In addition, the distance R5 from the center to the periphery of the metal layer 62 is longer than the distance R4 from the center to the inner periphery of the second planar coil. In other words, the second planar coil 12 includes a portion located between the first insulating portion 21 and the metal layer 62. As a result, the electric field strength at the lower end LE2 on the inner peripheral side of the second planar coil 12 can be further reduced.

[0087] Thus, in the isolators 100 to 130, the distance R2 from the center to the periphery of the second planar coil 12 is made longer than the distance R1 from the center to the periphery of the first planar coil 11, thereby reducing the electric field strength at the lower end LE1 on the outer periphery of the second planar coil 12. Furthermore, by configuring the metal layer 62, the electric field strength at the lower end LE2 on the inner periphery of the second planar coil 12 can be reduced, thereby avoiding insulation breakdown between the first planar coil 11 and the second planar coil 12.

[0088] In order to achieve a desired dielectric withstand capability between the first planar coil 11 and the second planar coil 12 , the configurations of the first planar coil 11 , the second planar coil 12 , and the metal layer 62 shown in the isolators 100 to 130 may be combined with each other.

[0089] Fig. 9 Schematic cross-sectional views showing an isolator 100r of a comparative example and an isolator 100p of a modified example of the first embodiment.

[0090] The isolator 100r includes a first planar coil 11, a second planar coil 12, a metal layer 62, and a conductor 50r. The distance R1 from the center to the periphery of the first planar coil 11 (see Figure 2 ) and the distance R2 from the center to the periphery of the second planar coil 12 (refer to Figure 2 )same.

[0091] The conductor 50r includes a first conductive portion 51r, a second conductive portion 52, and a third conductive portion 53, and is provided to surround the first planar coil 11 and the second planar coil 12. For example, a distance R1 from the first conductive portion 51r to the first planar coil 11 is substantially the same as a distance R2 from the third conductive portion 53 to the second planar coil 12.

[0092] The isolator 100p includes a first planar coil 11, a second planar coil 12, a metal layer 62, and a conductor 50p. The distance R1 from the center to the periphery of the first planar coil 11 (see Figure 2 ), is greater than the distance R2 from the center to the periphery of the second planar coil 12 (refer to Figure 2 )short.

[0093] The conductor 50p includes a first conductive portion 51p, a second conductive portion 52, and a third conductive portion 53, and is disposed to surround the first planar coil 11 and the second planar coil 12. For example, a distance R1 from the first conductive portion 51p to the first planar coil 11 is substantially the same as a distance R2 from the third conductive portion 53 to the second planar coil 12.

[0094] That is, the first conductive portion 51p extends longer toward the first planar coil 11 than the first conductive portion 51r. For example, when a circuit (not shown) connected to the first planar coil 11 is provided on the surface side of the substrate 5 between the substrate 5 and the first conductive portion 51p, the first conductive portion 51p can be arranged at a position closer to the first planar coil 11 than the isolator 100r in the isolator 100p. Thus, in the isolator 100p, for example, the dimension in the X direction can be reduced by the length Lx by which the first conductive portion 51p extends in the direction of the first planar coil 11.

[0095] (Second Embodiment)

[0096] Fig.10 2 is a schematic cross-sectional view showing an isolator 200 according to the second embodiment. Fig.10 In the figure, the wiring layer 70 between the substrate 5 and the insulating portion 20 is omitted. The same is true in the following drawings.

[0097] like Fig.10 As shown, in the isolator 200, the distance R5 from the center to the periphery of the metal layer 62 is made longer than the distance R2 from the center to the periphery of the second planar coil 12. In this example, the distance R2 from the center to the periphery of the second planar coil 12 is the same as the distance R1 from the center to the periphery of the first planar coil 11. In addition, the distance R4 from the center to the inner periphery of the second planar coil 12 may also be the same as the distance R3 from the center to the inner periphery of the first planar coil 11.

[0098] Fig.11 (a) and (b) are schematic diagrams showing the characteristics of the isolator 200 according to the second embodiment. Fig.11 (a) is a cross-sectional view showing the electric field distribution between the first planar coil 11 and the second planar coil 12 . Fig.11 (b) is a graph showing the charge intensity at the lower end LE1 on the outer peripheral side of the second planar coil 12 .

[0099] like Fig.11 As shown in (a), it can be seen that the interval between equipotential surfaces is narrowed at the upper end UE1 on the outer peripheral side of the first planar coil 11, the lower end LE1 on the outer peripheral side of the second planar coil 12, and the outer periphery of the metal layer 62, and the electric field intensity increases.

[0100] For example, the outer periphery of the metal layer 62 is located at a long distance from the first planar coil 11, which helps to reduce the possibility of insulation breakdown caused by electric field concentration. In addition, the electric field strength at the upper end UE1 of the first planar coil 11 is lower than the electric field strength at the lower end LE1 of the second planar coil 12. Therefore, in order to avoid insulation breakdown between the first planar coil 11 and the second planar coil, it is sufficient to reduce the electric field strength at the lower end LE1 of the second planar coil 12.

[0101] Fig.11 (b) is a graph showing the change in electric field strength at the lower end LE1 of the second planar coil 12. The vertical axis is the electric field strength at the lower end LE1, and the horizontal axis is the difference ΔR3 (= R5-R2) between the distance R5 from the center to the periphery of the metal layer 62 and the distance R2 from the center to the periphery of the second planar coil 12.

[0102] like Fig.11As shown in (b), if ΔR3 is made greater than zero, the electric field strength at the lower end LE1 is reduced. That is, by making the end of the metal layer 62 protrude outward from the outer periphery of the second planar coil 12, the electric field strength at the lower end LE1 of the second planar coil 12 can be reduced. At the same time, the electric field strength at the upper end UE1 of the first planar coil 11 is further reduced.

[0103] In this way, in the isolator 200, by making the distance R5 from the center to the periphery of the metal layer 62 longer than the distance R2 from the center to the periphery of the second planar coil 12, the electric field concentration at the lower end LE2 of the second planar coil 12 can be alleviated, thereby avoiding insulation breakdown between the first planar coil 11 and the second planar coil 12.

[0104] Fig.12 2 is a schematic cross-sectional view showing an isolator 210 according to a modification of the second embodiment. In the isolator 210 , a distance R5 from the center to the periphery of the metal layer 62 is made longer than a distance R2 from the center to the periphery of the second planar coil 12 .

[0105] Furthermore, the distance R2 from the center to the periphery of the second planar coil 12 is longer than the distance R1 from the center to the periphery of the first planar coil 11. In addition, the distance R4 from the center to the inner periphery of the second planar coil 12 is shorter than the distance R3 from the center to the inner periphery of the first planar coil 11. Thus, the electric field concentration at the lower end LE2 of the second planar coil 12 can be further alleviated, and the insulation breakdown between the first planar coil 11 and the second planar coil 12 can be avoided.

[0106] The isolator of the second embodiment is not limited to the above example, and may be configured as Figure 2 The first planar coil 11 and the second planar coil 12 are shown.

[0107] (Third Embodiment)

[0108] Fig.13 It is a top view showing an isolator according to a third embodiment.

[0109] Fig.14 It is a schematic diagram showing a cross-sectional structure of an isolator according to a third embodiment.

[0110] In the isolator 300 of the third embodiment, as Fig.13 As shown, one end of the outer peripheral portion of the first planar coil 11 is electrically connected to the conductor 50 via the wiring 73. The other end of the first planar coil 11 is electrically connected to the first circuit 1 via the wiring 60.

[0111] like Fig.14As shown, the first circuit 1 is provided in the substrate 5. The second circuit 2 is provided in the substrate 6 separated from the substrate 5. The metal layer 62 is electrically connected to the metal layer 69 provided on the substrate 6 via the wiring 63. The metal layer 64 is electrically connected to the metal layer 68 provided on the substrate 6 via the wiring 65. The second circuit 2 is electrically connected to the metal layers 68 and 69.

[0112] In the isolator 300 , the structure of each embodiment described above can be applied to the structure above the substrate 5 . This can reduce the electric field intensity near the lower end of the end surface of the second planar coil 12 .

[0113] Fig.15 It is a plan view showing an isolator according to a first modified example of the third embodiment.

[0114] Fig.16 yes Fig.15 A1-A2 cross-sectional view. Fig.17 yes Fig.15 B1-B2 cross-sectional view.

[0115] Fig.18 It is a schematic diagram showing a cross-sectional structure of an isolator according to a first modified example of the third embodiment.

[0116] like Fig.15 As shown, the isolator 310 of the first modification example includes a first structure body 10 - 1 and a second structure body 10 - 2 .

[0117] like Fig.15 , Fig.16 and Fig.18 As shown, the first structure 10-1 includes a planar coil 11-1, a planar coil 12-1, an insulating portion 21-1, an insulating portion 22-1, a dielectric portion 31a, a dielectric portion 41a, a dielectric portion 42a, a conductor 50a, a metal layer 62a, a metal layer 64a, and a metal layer 66a.

[0118] The structures of the planar coil 11-1, the planar coil 12-1, the insulating portion 21-1, the insulating portion 22-1, the dielectric portion 31a, the dielectric portion 41a, the dielectric portion 42a, the conductor 50a, the metal layer 62a, the metal layer 64a and the metal layer 66a are respectively as follows, for example: Figure 2 The first planar coil 11, the second planar coil 12, the first insulating portion 21, the second insulating portion 22, the dielectric portion 31, the dielectric portion 41, the dielectric portion 42, the conductor 50, the metal layer 62, the metal layer 64 and the metal layer 66 shown have the same structure.

[0119] like Fig.15 , Fig.17 and Fig.18As shown, the second structure 10-2 includes a planar coil 11-2, a planar coil 12-2, an insulating portion 21-2, an insulating portion 22-2, a dielectric portion 31b, a dielectric portion 41b, a dielectric portion 42b, a conductor 50b, a metal layer 62b, a metal layer 64b, and a metal layer 66b.

[0120] The structures of the planar coil 11-2, the planar coil 12-2, the insulating portion 21-2, the insulating portion 22-2, the dielectric portion 31b, the dielectric portion 41b, the dielectric portion 42b, the conductor 50b, the metal layer 62b, the metal layer 64b and the metal layer 66b are respectively as follows, for example: Figure 2 The first planar coil 11, the second planar coil 12, the first insulating portion 21, the second insulating portion 22, the dielectric portion 31, the dielectric portion 41, the dielectric portion 42, the conductor 50, the metal layer 62, the metal layer 64 and the metal layer 66 shown have the same structure.

[0121] like Fig.15 As shown, metal layer 62a is electrically connected to metal layer 62b via wiring 63. Metal layer 64a is electrically connected to metal layer 64b via wiring 65.

[0122] The metal layer 66a is electrically connected to other conductive members via the wiring 67a, and the metal layer 66b is electrically connected to other conductive members via the wiring 67b.

[0123] like Fig.18 As shown, the first circuit 1 is arranged in the substrate 5. The first structure 10-1 is arranged on the substrate 5. The second circuit 2 is arranged in the substrate 6. The second structure 10-2 is arranged on the substrate 6. One end of the planar coil 11-1 is electrically connected to the conductor 50a. The other end of the planar coil 11-1 is electrically connected to the first circuit 1. One end of the planar coil 11-2 is electrically connected to the conductor 50b. The other end of the planar coil 11-2 is electrically connected to the second circuit 2.

[0124] In the isolator 310, the structures of the above-described embodiments can be applied to the structures above the substrate 5 and the structures above the substrate 6. As a result, the electric field strength near the lower end of the end face of the planar coil 12-1 can be reduced. In addition, the electric field strength near the lower end of the end face of the planar coil 12-2 can be reduced. Figures 15 to 18 In the isolator 310 shown, a pair of planar coils 11-1 and 12-1 are connected in series with a pair of planar coils 11-2 and 12-2. In other words, the first circuit 1 and the second circuit 2 are doubly insulated by the two pairs of planar coils connected in series. According to the isolator 310, the insulation reliability can be improved compared with a structure in which a pair of planar coils are used for single insulation.

[0125] Fig.19It is a plan view showing an isolator according to a second modified example of the third embodiment.

[0126] Fig. 20 It is a schematic diagram showing a cross-sectional structure of an isolator according to a second modified example of the third embodiment.

[0127] like Fig.19 and Fig. 20 As shown, the isolator 320 of the second variation of the third embodiment is different from the isolator 300 in that both ends of the first planar coil 11 are electrically connected to the first circuit 1. The conductor 50 is electrically isolated from the first circuit 1 and the first planar coil 11. If the conductor 50 is set to a reference potential, the electrical connection relationship between the first circuit 1, the first planar coil 11 and the conductor 50 can be appropriately changed.

[0128] Fig.21 It is a schematic diagram showing an isolator according to a third modified example of the third embodiment.

[0129] The isolator 330 of the third variant includes a first structure 10-1, a second structure 10-2, a third structure 10-3 and a fourth structure 10-4. The first structure 10-1 includes a planar coil 11-1 and a planar coil 12-1. The second structure 10-2 includes a planar coil 11-2 and a planar coil 12-2. The third structure 10-3 includes a planar coil 11-3 and a planar coil 12-3. The fourth structure 10-4 includes a planar coil 11-4 and a planar coil 12-4. Each planar coil is a coil. The first circuit 1 includes a differential drive circuit 1a, a capacitor C1 and a capacitor C2. The second circuit 2 includes a differential receiving circuit 2a, a capacitor C3 and a capacitor C4.

[0130] For example, the differential drive circuit 1a, the capacitor C1, the capacitor C2, the planar coil 11-1, the planar coil 11-2, the planar coil 12-1, and the planar coil 12-2 are formed on a first substrate (not shown). One end of the planar coil 11-1 is connected to a first constant potential. The other end of the planar coil 11-2 is connected to the capacitor C1. One end of the planar coil 11-1 is connected to a second constant potential. The other end of the planar coil 11-2 is connected to the capacitor C2.

[0131] One output of the differential drive circuit 1a is connected to the capacitor C1. The other output of the differential drive circuit 1a is connected to the capacitor C2. The capacitor C1 is connected between the differential drive circuit 1a and the planar coil 11-1. The capacitor C2 is connected between the differential drive circuit 1a and the planar coil 11-2.

[0132] The planar coil 11-1 and the planar coil 12-1 are stacked with an insulating portion interposed therebetween. The planar coil 11-2 and the planar coil 12-2 are stacked with another insulating portion interposed therebetween. One end of the planar coil 12-1 is connected to one end of the planar coil 12-2.

[0133] For example, the differential receiving circuit 2a, the capacitor C3, the capacitor C4, the planar coil 11-3, the planar coil 11-4, the planar coil 12-3 and the planar coil 12-4 are formed on a second substrate not shown. One end of the planar coil 11-3 is connected to the third constant potential. The other end of the planar coil 11-3 is connected to the capacitor C3. One end of the planar coil 11-4 is connected to the fourth constant potential. The other end of the planar coil 11-4 is connected to the capacitor C4.

[0134] One input of the differential receiving circuit 2a is connected to the capacitor C3. The other input of the differential receiving circuit 2a is connected to the capacitor C4. The planar coil 11-3 and the planar coil 12-3 are stacked with an insulating portion. The planar coil 11-4 and the planar coil 12-4 are stacked with another insulating portion. One end of the planar coil 12-3 is connected to one end of the planar coil 12-4. The other end of the planar coil 12-3 is connected to the other end of the planar coil 12-1. The other end of the planar coil 12-4 is connected to the other end of the planar coil 12-2.

[0135] The operation is described below. In the transformer (or isolator), the modulated signal is transmitted. Fig.21 In the figure, Vin represents the modulated signal. In the modulation of the signal, for example, an edge trigger method or an on-off keying method is used. Regardless of the method, Vin is a signal that shifts the original signal to a high frequency band.

[0136] The differential drive circuit 1a causes current i0 in opposite directions to flow through the planar coil 11-1 and the planar coil 11-2 according to Vin. The planar coils 11-1 and 11-2 generate magnetic fields (H1) in opposite directions. When the number of turns of the planar coil 11-1 is the same as that of the planar coil 11-2, the magnitudes of the generated magnetic fields are equal.

[0137] The induced voltage generated in the planar coil 12-1 by the magnetic field H1 is added to the induced voltage generated in the planar coil 12-2 by the magnetic field H1. The current i1 flows in the planar coils 12-1 and 12-2. The planar coils 12-1 and 12-2 are connected to the planar coil 12-3 and the planar coil 12-4 respectively by bonding wires. The bonding wires contain, for example, gold. The diameter of the bonding wires is, for example, 30 μm.

[0138] The induced voltage added by the planar coils 12-1 and 12-2 is applied to the planar coils 12-3 and 12-4. A current i2 having the same value as the current i1 flowing through the planar coils 12-1 and 12-2 flows through the planar coils 12-3 and 12-4. The planar coils 12-3 and 12-4 generate magnetic fields (H2) in opposite directions to each other. When the number of turns of the planar coil 12-3 is the same as the number of turns of the planar coil 12-4, the magnitudes of the generated magnetic fields are equal to each other.

[0139] The direction of the induced voltage generated in the planar coil 11-3 by the magnetic field H2 is opposite to the direction of the induced voltage generated in the planar coil 11-4 by the magnetic field H2. The current i3 flows through the planar coils 11-3 and 11-4. In addition, the magnitude of the induced voltage generated in the planar coil 11-3 is the same as the magnitude of the induced voltage generated in the planar coil 11-4. The addition of the induced voltages generated in the planar coils 11-3 and 11-4 is applied to the differential receiving circuit 2a, and the modulated signal is transmitted.

[0140] Fig. 22 It is a perspective view showing a package according to a fourth embodiment.

[0141] Fig.23 It is a schematic diagram showing a cross-sectional structure of a package according to a fourth embodiment.

[0142] like Fig. 22 As shown, the package 400 of the fourth embodiment includes metal components 81 a to 81 f , metal components 82 a to 82 f , metal layers 83 a to 83 f , metal layers 84 a to 84 f , a sealing portion 90 , and a plurality of spacers 330 .

[0143] In the example shown in the figure, the package 400 includes four isolators 330. That is, Fig.21 In the illustrated example, four sets of the first structure body 10 - 1 to the fourth structure body 10 - 4 are provided.

[0144] A plurality of first structures 10-1 and a second structure 10-2 are provided on a portion of the metal component 81a. For example, a plurality of first structures 10-1 and a second structure 10-2 are provided on a substrate 5. The substrate 5 is electrically connected to the metal component 81a. A plurality of first circuits 1 corresponding to the first structures 10-1 and the second structures 10-2 are provided on the substrate 5.

[0145] A plurality of third structures 10-3 and a fourth structure 10-4 are provided on a portion of the metal component 82a. A plurality of third structures 10-3 and a fourth structure 10-4 are provided on a substrate 6. The substrate 6 is electrically connected to the metal component 82a. A plurality of second circuits 2 corresponding to the third structures 10-3 and the fourth structure 10-4 are provided on the substrate 6.

[0146] The metal component 81a is further electrically connected to the metal layer 83a. The metal layer 83a is electrically connected to the conductor 50a of each of the first structure 10-1 and the second structure 10-2. The metal component 82a is further electrically connected to the metal layer 84a. The metal layer 84a is electrically connected to the conductor 50b of each of the third structure 10-3 and the fourth structure 10-4.

[0147] The metal members 81b to 81e are electrically connected to the metal layers 83b to 83e, respectively. The metal layers 83b to 83e are electrically connected to the plurality of first circuits 1, respectively. The metal member 81f is electrically connected to the metal layer 83f, and the metal layer 83f is electrically connected to the plurality of first circuits 1.

[0148] The metal members 82b to 82e are electrically connected to the metal layers 84b to 84e, respectively. The metal layers 84b to 84e are electrically connected to the plurality of second circuits 2, respectively. The metal member 82f is electrically connected to the metal layer 84f, and the metal layer 84f is electrically connected to the plurality of second circuits 2.

[0149] The sealing portion 90 covers a portion of each of the metal members 81 a to 81 f and 82 a to 82 f , the metal layers 83 a to 83 f , the metal layers 84 a to 84 f , and the plurality of separators 330 .

[0150] The metal members 81a to 81f have terminals T1a to T1f, respectively. The metal members 82a to 82f have terminals T2a to T2f, respectively. The terminals T1a to T1f and T2a to T2f are not covered by the sealing portion 90 but are exposed to the outside.

[0151] For example, terminals T1a and T2a are connected to a reference potential. Signals to the first circuits 1 are input to terminals T1b to T1e. Signals from the second circuits 2 are output to terminals T2b to T2e. Terminal T1f is connected to a power supply for driving the first circuits 1. Terminal T2f is connected to a power supply for driving the second circuits 2.

[0152] According to the fourth embodiment, it is possible to reduce the possibility of destruction of the spacer in the package 400. Although the example in which four spacers 330 are provided is described here, one or more other spacers may be provided in the package 400.

[0153] Several embodiments of the present invention are illustrated above, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, changes, etc. can be made without departing from the scope of the main purpose of the invention. These embodiments and their modifications are included in the scope or main purpose of the invention, and are included in the invention described in the claims and the scope of their equivalents. In addition, the aforementioned embodiments can be implemented in combination with each other.

Claims

1. An isolator comprising: a substrate; a first planar coil disposed above the substrate along a surface of the substrate and disposed in a spiral shape along a plane of the surface of the substrate; a first insulating portion disposed on the first planar coil; A second planar coil is disposed on the first insulating portion and is arranged in a spiral shape along a plane of a surface of the first insulating portion; and a metal layer disposed above the first insulating portion; the first planar coil, the second planar coil, and the metal layer are arranged side by side in a first direction perpendicular to the surface of the substrate; the first planar coil and the second planar coil each have a center and an outer periphery in a second direction along the surface of the substrate; a first distance in the second direction from the center of the first planar coil to the outer periphery of the first planar coil is shorter than a second distance in the second direction from the center of the second planar coil to the outer periphery of the second planar coil; the greater the difference between the first distance and the second distance, the lower the electric field intensity at the lower end of the outer periphery side of the second planar coil; the first planar coil and the second planar coil each have an inner periphery in the second direction; a third distance in the second direction from the center of the first planar coil to the inner periphery of the first planar coil is longer than a fourth distance in the second direction from the center of the second planar coil to the inner periphery of the second planar coil; the greater the difference between the third distance and the fourth distance, the lower the electric field intensity at the lower end of the inner periphery side of the second planar coil; and a spacing between the first planar coil and the second planar coil in the first direction is wider than a spacing between the substrate and the first planar coil in the first direction.

2. The isolator according to claim 1, wherein: The center of the first planar coil, the center of the second planar coil, and the center of the metal layer are arranged side by side in the first direction.

3. The isolator according to claim 1, wherein: The invention further comprises: a second insulating portion provided on the first insulating portion; and a third insulating portion provided on the second insulating portion, wherein the second planar coil is provided in the second insulating portion, and the metal layer is provided in the third insulating portion.

4. The isolator according to claim 1, wherein: The metal layer is electrically connected to the second planar coil.

5. The isolator according to claim 1, wherein: A distance from a center to an outer periphery of the metal layer in the second direction is shorter than a distance from a center to an inner periphery of the second planar coil in the second direction.

6. The isolator according to claim 1, wherein: A distance between the substrate and the metal layer in the first direction is wider than a distance between the substrate and the second planar coil in the first direction.

7. The isolator according to claim 1, wherein: The second planar coil includes a portion located between the first insulating portion and the metal layer.

8. The isolator according to claim 5, wherein: The second planar coil and the metal layer include portions facing each other in the second direction.

9. The isolator according to claim 8, wherein: It also includes a second insulating portion arranged on the first insulating portion, the second planar coil is arranged in the second insulating portion, the metal layer includes a first part and a second part electrically connected to the first part, the first part is arranged in the second insulating portion, opposite to the second planar coil across the second insulating portion, and the second part is arranged above the first part.

10. The isolator according to claim 7, wherein: The first portion of the metal layer includes the same material as the second planar coil.

11. The isolator according to claim 9, wherein: A third insulating portion is further provided on the second insulating portion, and the second portion of the metal layer is provided in the third insulating portion.

12. The isolator according to claim 1, wherein: It also includes: a conductor arranged above the substrate, extending along the surface of the substrate, surrounding the first planar coil and the second planar coil; and a wiring layer arranged between the substrate and the first planar coil, including wiring that electrically connects the conductor to the first planar coil.

13. The isolator according to claim 12, wherein: The distance between the conductor and the first planar coil is the same as the distance between the conductor and the second planar coil.

14. The isolator according to claim 1, wherein: The device further includes: a first dielectric portion provided between the first planar coil and the first insulating portion; and a second dielectric portion provided between the first insulating portion and the second planar coil, wherein the first insulating portion is in contact with the first dielectric portion and the second dielectric portion.

15. The isolator according to claim 1, wherein: The device further includes: a transmitting circuit; and a receiving circuit, wherein one of the transmitting circuit and the receiving circuit is connected to the metal layer and one end of the second planar coil.

16. An isolator comprising: a substrate; a first planar coil arranged above the substrate along the surface of the substrate; a first insulating portion arranged on the first planar coil; a second planar coil arranged on the first insulating portion; and a metal layer arranged above the first insulating portion and the second planar coil, wherein the first planar coil, the second planar coil and the metal layer are arranged side by side in a first direction perpendicular to the surface of the substrate, the first planar coil, the second planar coil and the metal layer respectively have a center and a periphery in a second direction along the surface of the substrate, and a distance in the second direction from the center of the metal layer to the periphery of the metal layer is longer than a distance in the second direction from a center line of the second planar coil to the periphery of the second planar coil.

17. The isolator according to claim 16, wherein: The center of the first planar coil, the center of the second planar coil, and the center of the metal layer are arranged side by side in the first direction.

18. The isolator according to claim 16, wherein: It also includes: a second insulating portion arranged on the first insulating portion; and a third insulating portion arranged on the second insulating portion, the second planar coil is arranged in the second insulating portion, and the metal layer is arranged in the third insulating portion and is electrically connected to the second planar coil.

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