JP7332775B2 - isolator - Google Patents

Description

Embodiments of the present invention relate to isolators.

Isolators use changes in magnetic or electric fields to transmit signals while blocking current. It is desirable that this isolator is difficult to break.

U.S. Patent Application Publication No. 2011/0176339

A problem to be solved by the present invention is to provide an isolator capable of reducing the possibility of breakage.

An isolator according to an embodiment includes a substrate, a first planar coil provided above the substrate along the surface of the substrate, a first insulating section provided on the first planar coil, and the first planar coil. A second planar coil provided on one insulating portion, and a metal layer provided above the first insulating portion and the second planar coil. 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 distance from the center to the outer circumference is longer than the distance from the centerline to the outer circumference of the second planar coil.

1 is a schematic plan view showing an isolator according to a first embodiment; FIG. 1 is a schematic cross-sectional view showing an isolator according to a first embodiment; FIG. FIG. 3 is a schematic diagram showing characteristics of the isolator according to the first embodiment; FIG. 3 is a schematic diagram showing characteristics of the isolator according to the first embodiment; FIG. 3 is a schematic cross-sectional view showing characteristics of the isolator according to the first embodiment; FIG. 5 is a schematic cross-sectional view showing an isolator according to a modification of the first embodiment; FIG. 5 is a schematic cross-sectional view showing an isolator according to a modification of the first embodiment; FIG. 5 is a schematic cross-sectional view showing an isolator according to a modification of the first embodiment; FIG. 5 is a schematic cross-sectional view showing an isolator according to a modification of the first embodiment; FIG. 5 is a schematic cross-sectional view showing an isolator according to a second embodiment; FIG. 5 is a schematic diagram showing characteristics of an isolator according to the second embodiment; FIG. 11 is a schematic cross-sectional view showing an isolator according to a modification of the second embodiment; FIG. 11 is a plan view showing an isolator according to a third embodiment; FIG. 11 is a schematic diagram showing a cross-sectional structure of an isolator according to a third embodiment; FIG. 11 is a plan view showing an isolator according to a first modified example of the third embodiment; FIG. 16 is a cross-sectional view taken along line A1-A2 of FIG. 15; FIG. 16 is a cross-sectional view taken along line B1-B2 of FIG. 15; FIG. 11 is a schematic diagram showing a cross-sectional structure of an isolator according to a first modified example of the third embodiment; FIG. 11 is a plan view showing an isolator according to a second modified example of the third embodiment; FIG. 11 is a schematic diagram showing a cross-sectional structure of an isolator according to a second modified example of the third embodiment; FIG. 11 is a schematic diagram showing an isolator according to a third modified example of the third embodiment; It is a perspective view showing the package concerning a 4th embodiment. It is a schematic diagram showing the cross-sectional structure of the package which concerns on 4th Embodiment.

Each embodiment 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.
(First embodiment)
FIG. 1 is a plan view showing an isolator according to the first embodiment. FIG.
FIG. 2 is a cross-sectional view along A1-A2 in FIG.

The first embodiment relates to devices called, for example, digital isolators, galvanic isolators, and galvanic isolation elements. As shown in FIGS. 1 and 2, the isolator 100 according to 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, and a first insulating section. 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 . In FIG. 1, the insulating portions 28 and 29 are omitted.

The first planar coil 11, the second planar coil 12, and the metal layer 62 have, for example, a circular outer periphery, and share the center line CL in the direction (Z direction) perpendicular to the surface of the substrate 5, for example. placed. The outer peripheries of the first planar coil 11, the second planar coil 12, and the metal layer 62 are not limited to circular shapes, and may be, for example, polygonal or elliptical.

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 defined as the Z direction (first direction). Two directions which are perpendicular to the Z direction and which are perpendicular to each other along the surface of the substrate 5 are defined as an X direction (second direction) and a Y direction (third direction). For the sake of explanation, the direction from the first planar coil 11 to 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 are irrelevant to the direction of gravity.

As shown in FIG. 2, the insulating section 20 is provided on the substrate 5 with the wiring layer 70 interposed therebetween. 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 .

In the example shown in FIGS. 1 and 2, the first planar coil 11 and the second planar coil 12 are spirally provided along the XY plane. The first planar coil 11 and the second planar coil 12 face each other in the Z direction. At least part of the second planar coil 12 is aligned with at least part of the first planar coil 11 in the Z direction.

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

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 .

The conductor 50 is provided 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 provided around the first planar coil 11 along the XY plane. The second conductive portion 52 is provided on part of the first conductive portion 51 . A plurality of second conductive portions 52 are provided along the first conductive portion 51 . The third conductive portion 53 is provided on the plurality of second conductive portions 52 . The third conductive portion 53 is positioned around the second planar coil 12 along the XY plane.

In the example shown in FIG. 1 , 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 .

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 provided on one end of the second planar coil 12 . A metal layer 64 is provided on the other end of the second planar coil 12 . The Z-direction position of the metal layer 62 and the Z-direction position of the metal layer 64 may be the same as the Z-direction position of the second planar coil 12 . Metal layers 62 and 64 may be formed integrally with second planar coil 12 .

As shown in FIG. 2, a metal layer 66 is provided on the conductor 50 . The conductor 50 is electrically connected to a conductive member (not shown) through the metal layer 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. This reduces the possibility of unexpected dielectric breakdown occurring between the conductor 50 and each planar coil due to fluctuations in the potential of the conductor 50 .

Also, the substrate 5 may be provided with a circuit electrically connected to the first planar coil 11 . The first circuit 1 is, for example, part of a circuit provided on the substrate 5 . In this case, the conductor 50 is provided on the substrate 5 with the wiring layer 70 interposed therebetween, and the circuit is provided between the substrate 5 and the wiring layer 70, so that the substrate 5 and the conductor 50 are externally connected to the substrate. Circuits on the substrate 5 are shielded by conductors 50 against electromagnetic waves directed at 5 . As a result, the operation of the circuit can be stabilized. The wiring layer 70 includes wiring 73 that electrically connects the first planar coil 11 and the conductor 50 .

An 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 .

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 receiving circuit. Here, the case where the first circuit 1 is a transmission circuit and the second circuit 2 is a reception circuit will be described.

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

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

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.

The insulating portion 29 contains an insulating resin such as polyimide or polyamide.
Dielectric portion 31 contains, for example, silicon and nitrogen.

Dielectric portions 41 and 42 contain, for example, silicon and nitrogen. For example, dielectric portions 41 and 42 comprise silicon nitride.

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

The second planar coil 12 may include a first metal layer 12a and a second metal layer 12b. The second metal layer 12b is formed between the first metal layer 12a and the first insulating section 21, between the first metal layer 12a and the dielectric section 31, and between the first metal layer 12a and the second insulating section 22. placed in between. The first planar coil 11 may include a third metal layer 11c and a fourth metal layer 11d. The fourth metal layer 11 d is provided between the third metal layer 11 c and the insulating section 20 . The first metal layer 12a and the third metal layer 11c contain copper. The second metal layer 12b and the fourth metal layer 11d contain tantalum. The second metal layer 12b and the fourth metal layer 11d may include laminated films 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.

The first conductive portion 51 may include metal layers 51a and 51b. The metal layer 51 b is provided between the metal layer 51 a and the insulating section 20 . The second conductive portion 52 may include metal layers 52a and 52b. The metal layer 52 b is provided between the metal layer 52 a and the first insulating section 21 and between the metal layer 52 a and the first conductive section 51 . The third conductive portion 53 may include metal layers 53a and 53b. The metal layer 53 b is provided between the metal layer 53 a and the second insulating section 22 , between the metal layer 53 a and the dielectric section 31 , and between the metal layer 53 a and the second conductive section 52 . The metal layers 51a-53a contain copper. The metal layers 51b-53b contain tantalum. The metal layers 51b to 53b may include laminated films of tantalum and tantalum nitride. By providing the metal layers 51b to 53b, diffusion of the metal material contained in the metal layers 51a to 53a into each insulating portion can be suppressed.

In the isolator 100 according to the embodiment, when a signal is transmitted between the first planar coil 11 and the second planar coil 12, a positive voltage is applied to the second planar coil 12 with respect to the first planar coil 11. be. Thereby, 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, electric field concentration occurs at the lower end of the outer peripheral side of the second planar coil 12 , which may lead to dielectric breakdown between the first planar coil 11 and the second planar coil 12 . Therefore, it is desirable to reduce the electric field strength in the vicinity of the lower end LE1 (see FIG. 3A) to avoid destruction of the isolator 100. FIG.

In the isolator 100, as shown in FIG. 2, the X-direction distance R1 from the center line of the first planar coil 11 to the outer circumference is shorter than the distance R2 from the center to the outer circumference of the second planar coil 12. FIG. Also, the distance R3 from the center of the first planar coil 11 to the inner circumference is shorter than the distance R4 from the center of the second planar coil 12 to the inner circumference. A distance R5 from the center to the outer circumference of the metal layer 62 is shorter than a distance R4 from the center to the inner circumference of the second planar coil 12 (see FIG. 1).

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 .

3 to 5 are schematic diagrams showing characteristics of the isolator 100 according to the first embodiment.
3(a), 4(a), 4(b), 5(a) and 5(b) show the electric field intensity distribution between the first planar coil 11 and the second planar coil 12. It is a schematic cross-sectional view showing.

FIG. 3( a ) shows equipotential surfaces between the first planar coil 11 and the second planar coil 12 . The electric field strength is high in the portion where the distance between the equipotential surfaces is narrow, and the electric field strength is low as the distance between the equipotential surfaces is wide. The same applies to electric field distributions in the following drawings.

As shown in FIG. 3A, the electric field intensity is high 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. As shown in FIG. The electric field strength at the lower end LE1 of the second planar coil 12 is higher than the electric field strength at the upper end UE1 of the first planar coil 11 .

FIG. 3B is a graph showing the electric field intensity at the lower end LE1 on the outer peripheral side of the second planar coil 12. As shown in FIG. The vertical axis is the electric field intensity at the lower end LE1. The horizontal axis is the difference ΔR1 (=R2−R1) between the distance R2 from the center of the second planar coil 12 to the outer periphery and the distance R1 from the center of the first planar coil 11 to the outer periphery.

As shown in FIG. 3B, the electric field strength at the lower end LE1 decreases as ΔR1 increases. That is, the wider the ΔR1, 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 is relaxed, and the dielectric breakdown between the first planar coil 11 and the second planar coil 12 is prevented. can be avoided.

4(a) and 4(b) are cross-sectional views showing electric field distributions on the inner peripheral side of the first planar coil 11 and the second planar coil 12. FIG. The inner peripheral end of the first planar coil 11 is provided at a position closer to the center line CL (see FIG. 2) than the inner peripheral end of the second planar coil 12 .

In the example shown in FIG. 4A, electric field concentration occurs at the lower end LE2 of the second planar coil 12 on the inner peripheral side. On the other hand, in the example shown in FIG. 4B, the metal layer 62 is provided in the center of the second planar coil 12 (see FIG. 1). The metal layer 62 is provided, for example, at a position higher than the level of the top surface of the second planar coil 12 in the Y direction.

FIG. 4(c) is a graph showing the electric field intensity at the lower end LE2 on the inner peripheral side of the second planar coil 12. As shown in FIG. The vertical axis is the electric field strength at the lower end LE2. The horizontal axis represents 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 to the inner circumference of the first planar coil 11 (FIG. 2 reference).

FIG. 4C shows the characteristic A when the metal layer 62 is not arranged and the characteristic B when the metal layer 62 is arranged. In the characteristic A, the electric field strength at the lower end LE2 increases as ΔR2 increases. On the other hand, in the characteristic B, the electric field intensity at the lower end LE2 does not increase, and the electric field intensity at the lower end LE1 of FIG. 3(a) decreases as shown in FIG. 3(b).

By arranging the metal layer 62 in this manner, electric field concentration at the lower end LE on the inner peripheral side of the second planar coil 12 is alleviated, and dielectric breakdown between the first planar coil 11 and the second planar coil 12 is prevented. can be avoided.

5A and 5B are cross-sectional views showing another electric field distribution on the outer peripheral side of the first planar coil 11 and the second planar coil.

In the example shown in FIG. 5A, the Z-direction spacing T1 between the first planar coil 11 and the second planar coil 12 is wider than the Z-direction spacing T2 between the substrate 5 and the first planar coil 11 . On the other hand, in the example shown in FIG. 5B, the interval T1 is narrower than the interval T2.

In the example shown in FIG. 5B, an electric field distribution is generated such that the equipotential surface wraps around between the substrate 5 and the end of the first planar coil 11 on the outer peripheral side. As a result, the electric field strength at the upper end UE2 on the inner peripheral side of the first planar coil 11 increases.

Thus, in order to avoid dielectric breakdown between the first planar coil 11 and the second planar coil 12, the Z-direction spacing T1 between the first planar coil 11 and the second planar coil 12 should be and the first planar coil 11 in the Z direction.

6 to 8 are schematic cross-sectional views respectively showing isolators 110, 120 and 130 according to modifications of the first embodiment.

In the isolator 110 shown in FIG. 6, the distance R5 in the X direction from the center to the outer 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, and the metal layer 62 is located on the second plane. It is arranged in a space surrounded by the inner circumference of the coil 12 . The metal layer 62 is electrically connected to the second planar coil 12 at a portion not shown.

At least part of the metal layer 62 faces the inner circumference of the second planar coil 12 in the direction along the surface of the substrate 5 (for example, the X direction). As a result, the electric field strength at the lower end LE2 (see FIG. 4(b)) on the inner peripheral side of the second planar coil 12 can be further reduced.

In the isolator 120 shown in FIG. 7, the distance R1 from the center to the outer circumference of the first planar coil 11 is shorter than the distance R2 from the center to the outer circumference of the second planar coil 12, and is longer than the distance R4 from the center of the second planar coil 12 to the inner periphery.

That is, the interval (R1-R3) between the outer circumference and the inner circumference of the first planar coil 11 is set narrower than the interval (R2-R4) between the outer circumference and the inner circumference of the second planar coil 12. FIG. 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 reduced (see FIGS. 3A and 3B). Also, by arranging the metal layer 62, the electric field strength at the lower end LE2 can be further reduced (see FIG. 4(b)).

Also 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 distance between the outer circumference and the inner circumference of the first planar coil 11 (R1-R3 ) can be reduced.

By making the number of turns of the first planar coil 11 the same as the number of turns of the second planar coil 12, the design of the magnetic coupling between the first planar coil 11 and the second planar coil 12 can be facilitated. can.

In the isolator 130 shown in FIG. 8, the metal layer 62 is positioned above the top surface of the second planar coil 12 in the Z direction. Furthermore, the distance R5 from the center to the outer 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 intensity at the lower end LE2 on the inner peripheral side of the second planar coil 12 can be further reduced.

As described above, in isolators 100 to 130, the distance R2 from the center to the outer circumference of the second planar coil 12 is longer than the distance R1 from the center to the outer circumference of the first planar coil 11, so that the second planar coil 12 reduces the electric field intensity at the lower end LE1 on the outer peripheral side of the . Furthermore, by arranging the metal layer 62, the electric field intensity at the lower end LE2 on the inner peripheral side of the second planar coil 12 is reduced, and dielectric breakdown between the first planar coil 11 and the second planar coil 12 is avoided. be able to.

Also, the configuration of the first planar coil 11, the second planar coil 12 and the metal layer 62 shown in the isolators 100-130 achieves the desired dielectric strength between the first planar coil 11 and the second planar coil 12. Therefore, they can be combined with each other.

FIG. 9 is a schematic cross-sectional view showing an isolator 100r according to a comparative example and an isolator 100p according to a modified example of the first embodiment.

The isolator 100r includes a first planar coil 11, a second planar coil 12, a metal layer 62, and a conductor 50r. A distance R1 (see FIG. 2) from the center of the first planar coil 11 to the outer periphery is the same as a distance R2 (see FIG. 2) from the center of the second planar coil 12 to the outer periphery.

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

The isolator 100p includes a first planar coil 11, a second planar coil 12, a metal layer 62, and a conductor 50p. A distance R1 (see FIG. 2) from the center of the first planar coil 11 to the outer periphery is shorter than a distance R2 (see FIG. 2) from the center of the second planar coil 12 to the outer periphery.

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

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 isolator 100p has a higher It can be arranged at a position closer to the one-plane coil 11 . Accordingly, in the isolator 100p, the size in the X direction can be reduced by, for example, the length Lx obtained by extending the first conductive portion 51p in the direction of the first planar coil 11. FIG.

(Second embodiment)
FIG. 10 is a schematic cross-sectional view showing an isolator 200 according to the second embodiment. Note that the wiring layer 70 between the substrate 5 and the insulating portion 20 is omitted in FIG. The same applies to the following drawings.

As shown in FIG. 10, in the isolator 200, the distance R5 from the center of the metal layer 62 to the outer periphery is set longer than the distance R2 from the center of the second planar coil 12 to the outer periphery. In this example, the distance R2 from the center of the second planar coil 12 to the outer periphery is the same as the distance R1 from the center of the first planar coil 11 to the outer periphery. Also, the distance R4 from the center of the second planar coil 12 to the inner periphery may be the same as the distance R3 from the center of the first planar coil 11 to the inner periphery.

FIGS. 11A and 11B are schematic diagrams showing characteristics of the isolator 200 according to the second embodiment. FIG. 11(a) is a sectional view showing the electric field distribution between the first planar coil 11 and the second planar coil 12. FIG. FIG. 11(b) is a graph showing the electric charge intensity at the lower end LE1 on the outer peripheral side of the second planar coil 12. As shown in FIG.

As shown in FIG. 11(a), 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, the interval between the equipotential surfaces narrows and the electric field strength increases. is found to be on the rise.

For example, the outer circumference of the metal layer 62 is positioned at a long distance from the first planar coil 11 and is less likely to contribute to dielectric breakdown due to electric field concentration. Also, the electric field intensity at the upper end UE1 of the first planar coil 11 is lower than the electric field intensity at the lower end LE1 of the second planar coil 12. FIG. Therefore, in order to avoid dielectric breakdown between the first planar coil 11 and the second planar coil, the electric field strength at the lower end LE1 of the second planar coil 12 should be reduced.

FIG. 11(b) is a graph showing changes in electric field strength at the lower end LE1 of the second planar coil 12. As shown in FIG. The vertical axis is the electric field intensity at the lower end LE1, and the horizontal axis is the difference ΔR3 (=R5− R2).

As shown in FIG. 11(b), when ΔR3 is made greater than zero, the electric field strength at the lower end LE1 is reduced. That is, the electric field strength at the lower end LE1 of the second planar coil 12 can be lowered by protruding the end of the metal layer 62 from the outer periphery of the second planar coil 12 to the outside. At the same time, the electric field intensity at the upper end UE1 of the first planar coil 11 is also further reduced.

Thus, in the isolator 200, the distance R5 from the center to the outer periphery of the metal layer 62 is longer than the distance R2 from the center to the outer periphery of the second planar coil 12, so that the lower end LE2 of the second planar coil 12 is Electric field concentration can be relaxed, and dielectric breakdown between the first planar coil 11 and the second planar coil 12 can be avoided.

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

Furthermore, the distance R2 from the center of the second planar coil 12 to the outer periphery is longer than the distance R1 from the center of the first planar coil 11 to the outer periphery. Further, the distance R4 from the center of the second planar coil 12 to the inner circumference is shorter than the distance R3 from the center of the first planar coil 11 to the inner circumference. As a result, electric field concentration at the lower end LE2 of the second planar coil 12 can be further alleviated, and dielectric breakdown between the first planar coil 11 and the second planar coil 12 can be avoided.

The isolator according to the second embodiment is not limited to the above example, and for example, the first planar coil 11 and the second planar coil 12 shown in FIG. 2 may be arranged.

(Third Embodiment)
FIG. 13 is a plan view showing an isolator according to the third embodiment.
FIG. 14 is a schematic diagram showing the cross-sectional structure of an isolator according to the third embodiment.

In the isolator 300 according to the third embodiment, one end of the outer peripheral portion of the first planar coil 11 is electrically connected to the conductor 50 via the wiring 73 as shown in FIG. The other end of the first planar coil 11 is electrically connected to the first circuit 1 via the wiring 60 .

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

In the isolator 300, the structure according to each embodiment already described can be applied to the structure above the substrate 5. FIG. Thereby, the electric field strength near the lower end of the end surface of the second planar coil 12 can be reduced.

FIG. 15 is a plan view showing an isolator according to a first modified example of the third embodiment; FIG.
16 is a cross-sectional view taken along line A1-A2 of FIG. 15. FIG. 17 is a cross-sectional view taken along line B1-B2 of FIG. 15. FIG.
FIG. 18 is a schematic diagram showing the cross-sectional structure of an isolator according to the first modification of the third embodiment.

The isolator 310 according to the first modification includes a first structure 10-1 and a second structure 10-2, as shown in FIG.

As shown in FIGS. 15, 16, and 18, 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 It includes portion 31a, dielectric portion 41a, dielectric portion 42a, conductor 50a, metal layer 62a, metal layer 64a, and metal layer 66a.

Planar coil 11-1, planar coil 12-1, insulating portion 21-1, insulating portion 22-1, dielectric portion 31a, dielectric portion 41a, dielectric portion 42a, conductor 50a, metal layer 62a, metal layer 64a , and the metal layer 66a are, for example, 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 structures of the dielectric portion 42, the conductor 50, the metal layer 62, the metal layer 64, and the metal layer 66 are similar to each other.

As shown in FIGS. 15, 17, and 18, 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 It includes portion 31b, dielectric portion 41b, dielectric portion 42b, conductor 50b, metal layer 62b, metal layer 64b, and metal layer 66b.

Planar coil 11-2, planar coil 12-2, insulating part 21-2, insulating part 22-2, dielectric part 31b, dielectric part 41b, dielectric part 42b, conductor 50b, metal layer 62b, metal layer 64b , and the metal layer 66b are, for example, 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 structures of the dielectric portion 42, the conductor 50, the metal layer 62, the metal layer 64, and the metal layer 66 are similar to each other.

As shown in FIG. 15, the metal layer 62a is electrically connected to the metal layer 62b by the wiring 63. As shown in FIG. The metal layer 64a is electrically connected to the metal layer 64b by the wiring 65 .

The metal layer 66a is electrically connected to another conductive member by a wiring 67a. The metal layer 66b is electrically connected to another conductive member by a wiring 67b.

As shown in FIG. 18, the first circuit 1 is provided in the substrate 5. As shown in FIG. The first structure 10-1 is provided on the substrate 5. As shown in FIG. A second circuit 2 is provided in the substrate 6 . The second structure 10-2 is provided on the substrate 6. As shown in FIG. One end of the planar coil 11-1 is electrically connected to the conductor 50a. The other end of planar coil 11-1 is electrically connected to first circuit 1. FIG. One end of the planar coil 11-2 is electrically connected to the conductor 50b. The other end of planar coil 11-2 is electrically connected to second circuit 2. FIG.

In the isolator 310 , the structure according to each embodiment already described can be applied to the structure above the substrate 5 and the structure above the substrate 6 . As a result, the electric field strength near the lower end of the end surface of the planar coil 12-1 can be reduced. Also, the electric field strength near the lower end of the end face of the planar coil 12-2 can be reduced. In the isolator 310 shown in FIGS. 15 to 18, 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 two pairs of planar coils connected in series. The isolator 310 can improve insulation reliability compared to a structure in which a pair of planar coils is single-layered.

FIG. 19 is a plan view showing an isolator according to a second modification of the third embodiment;
FIG. 20 is a schematic diagram showing a cross-sectional structure of an isolator according to a second modification of the third embodiment.

As shown in FIGS. 19 and 20, the isolator 320 according to the second modification of the third embodiment is an isolator in that both ends of the first planar coil 11 are electrically connected to the first circuit 1. Different from 300. The conductor 50 is electrically separated from the first circuit 1 and the first planar coil 11 . If the conductor 50 is set to the reference potential, the electrical connection relationship between the first circuit 1, the first planar coil 11, and the conductor 50 can be changed as appropriate.

FIG. 21 is a schematic diagram showing an isolator according to a third modification of the third embodiment.
An isolator 330 according to the third modification 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 driver 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.

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

One output of the differential driver circuit 1a is connected to the capacitor C1. The other output of the differential driver circuit 1a is connected to the capacitor C2. A capacitor C1 is connected between the differential driver circuit 1a and the planar coil 11-1. Capacitor C2 is connected between differential driver circuit 1a and planar coil 11-2.

A planar coil 11-1 and a planar coil 12-1 are laminated with an insulating portion interposed therebetween. A planar coil 11-2 and a planar coil 12-2 are stacked with another insulating portion interposed therebetween. One end of planar coil 12-1 is connected to one end of planar coil 12-2.

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

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. A planar coil 11-3 and a planar coil 12-3 are laminated with an insulating portion interposed therebetween. A planar coil 11-4 and a planar coil 12-4 are laminated with another insulating portion interposed therebetween. One end of the planar coil 12-3 is connected to one end of the planar coil 12-4. The other end of planar coil 12-3 is connected to the other end of planar coil 12-1. The other end of planar coil 12-4 is connected to the other end of planar coil 12-2.

Operation will be explained. A modulated signal is transmitted in the transformer (or isolator). In FIG. 21, Vin represents the modulated signal. For signal modulation, for example, an edge trigger method or an On-Off Keying method is used. In either method, Vin is a signal obtained by shifting the original signal to a higher frequency band.

The differential driver circuit 1a causes currents i0 in opposite directions to flow through the planar coils 11-1 and 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 the number of turns of the planar coil 11-2, the magnitudes of the generated magnetic fields are equal.

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. A current i1 flows through the planar coils 12-1 and 12-2. The planar coils 12-1 and 12-2 are connected to the planar coils 12-3 and 12-4 by bonding wires, respectively. The bonding wire contains gold, for example. The diameter of the bonding wire is, for example, 30 μm.

The induced voltages added by the planar coils 12-1 and 12-2 are 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. Planar coils 12-3 and 12-4 generate magnetic fields (H2) in opposite directions. 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.

The direction of the voltage induced in the planar coil 11-3 by the magnetic field H2 is opposite to the direction of the voltage induced in the planar coil 11-4 by the magnetic field H2. A current i3 flows through the planar coils 11-3 and 11-4. Also, 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. Addition of induced voltages generated by the planar coils 11-3 and 11-4 is applied to the differential receiving circuit 2a, and a modulated signal is transmitted.

FIG. 22 is a perspective view showing a package according to the fourth embodiment.
FIG. 23 is a schematic diagram showing the cross-sectional structure of the package according to the fourth embodiment.

The package 400 according to the fourth embodiment includes metal members 81a to 81f, metal members 82a to 82f, metal layers 83a to 83f, metal layers 84a to 84f, a sealing portion 90, and a plurality Includes isolator 330 .

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

A plurality of first structures 10-1 and second structures 10-2 are provided on part of the metal member 81a. For example, a plurality of first structures 10-1 and second structures 10-2 are provided on one substrate 5. FIG. The substrate 5 is electrically connected to the metal member 81a. A plurality of first circuits 1 corresponding to the respective first structures 10-1 and second structures 10-2 are provided in the substrate 5. As shown in FIG.

A plurality of third structures 10-3 and fourth structures 10-4 are provided on part of the metal member 82a. A plurality of third structures 10 - 3 and fourth structures 10 - 4 are provided on one substrate 6 . The substrate 6 is electrically connected to the metal member 82a. A plurality of second circuits 2 are provided in the substrate 6 corresponding to the respective third structures 10-3 and fourth structures 10-4.

The metal member 81a is also electrically connected to the metal layer 83a. The metal layer 83a is electrically connected to the conductors 50a of the first structures 10-1 and the second structures 10-2. The metal member 82a is also electrically connected to the metal layer 84a. The metal layer 84a is electrically connected to the conductors 50b of the respective third structures 10-3 and fourth structures 10-4.

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

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

The sealing portion 90 covers a portion of each of the metal members 81 a - 81 f and 82 a - 82 f, the metal layers 83 a - 83 f, the metal layers 84 a - 84 f, and the plurality of isolators 330 .

The metal members 81a-81f have terminals T1a-T1f, respectively. Metal members 82a-82f have terminals T2a-T2f, respectively. The terminals T1a to T1f and T2a to T2f are not covered with the sealing portion 90 and are exposed to the outside.

For example, terminals T1a and T2a are connected to a reference potential. Signals to the respective first circuits 1 are input to the terminals T1b to T1e. Signals from the second circuits 2 are output to the terminals T2b to T2e. The terminal T1f is connected to a power source for driving the multiple first circuits 1 . A terminal T2f is connected to a power source for driving the plurality of second circuits 2 .

According to the fourth embodiment, the possibility of isolator breakage in the package 400 can be reduced. Although an example in which four isolators 330 are provided has been described here, the package 400 may be provided with one or more other isolators.

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.

Reference Signs List 1 First circuit 1a Differential driver circuit 2 Second circuit 2a Differential receiving circuit 5, 6 Substrate 10-1 First structure 10-2 Second structure 10-3... Third structure, 10-4... Fourth structure, 11... First planar coil, 11-1, 11-2, 11-3, 11-4, 12-1, 12-2, 12 -3, 12-4... planar coils, 11c, 11d, 12a, 12b, 51a, 51b, 52a, 52b, 53a, 53b, 62, 62a, 62b, 64, 64a, 64b, 66, 66a, 66b, 68, 69, 83a, 83b, 83f, 84a, 84b, 84f... Metal layer 12... Second planar coil 20, 28, 29... Insulating part 21... First insulating part 22... Second insulating part 31, 31a , 31b, 41, 41a, 41b, 42, 42a, 42b... Dielectric parts 50, 50a, 50b, 50r, 50p... Conductors 51, 51p, 51r, 51p... First conductive parts 52,... Second Conductive portion 53 Third conductive portion 60, 63, 65, 67, 67a, 67b, 73 Wiring 70 Wiring layer 81a, 81b, 81f, 82a, 82b, 82f Metal member 90 Sealing Part 100, 100p, 100r, 110, 120, 130, 200, 210, 300, 310, 320, 330, 400... Isolator 400... Package CL... Center line H1, H2... Magnetic field LE1, LE2... Lower end , T1a, T1b to T1f, T2a, T2b to T2f... terminals, UE1, UE2... upper end

Claims (7)

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;
a metal layer provided above the first insulating portion and the second planar coil;
with
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 isolator, wherein in a second direction along the surface of the substrate, the distance from the center to the periphery of the metal layer is longer than the distance from the centerline to the periphery of the second planar coil. 2. The isolator according to claim 1, wherein the center of said first planar coil, said center of said second planar coil and said center of said metal layer are aligned in said first direction. 3. The isolator according to claim 2, wherein the distance in the second direction from the center to the outer circumference of the first planar coil is shorter than the distance in the second direction from the center to the outer circumference of the second planar coil. 3. The isolator according to claim 2, wherein the distance in the second direction from the center to the inner periphery of the first planar coil is greater than the distance in the second direction from the center to the inner periphery of the second planar coil. 2. The isolator according to claim 1, wherein the distance between said first planar coil and said second planar coil in said first direction is wider than the distance between said substrate and said first planar coil in said first direction. 2. The isolator of claim 1, further comprising a conductor disposed above said substrate and extending along said surface of said substrate and surrounding said first planar coil and said second planar coil. 7. The isolator according to claim 6, wherein the distance between said conductor and said first planar coil is substantially the same as the distance between said conductor and said second planar coil.

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