Digital isolator

Abstract

The present application provides a digital isolator capable of improving insulation breakdown resistance. The digital isolator of the embodiment is provided with a first electrode, a first insulating portion, a second electrode, a second insulating portion, and a first dielectric portion. The first insulating portion is disposed below the first electrode. The second electrode is disposed below the first insulating portion. The second insulating portion is disposed around the first electrode along a first face perpendicular to a first direction from the second electrode toward the first electrode. The first dielectric portion is disposed between the first electrode and the second insulating portion in a second direction along the first face, in contact with the first electrode. The relative dielectric constant of the first dielectric portion is higher than the relative dielectric constant of the first insulating portion.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to a digital isolator. BACKGROUND

[0002] A digital isolator transmits a signal using a change in a magnetic field or an electric field in a state where a current is cut off. With regard to the digital isolator, it is preferable that the insulation breakdown resistance be high.

[0003] [Patent Literature]

[0004] [Patent Literature]

[0005] [Patent Literature 1] Japanese Patent Application Laid-Open No. 2017-538277 SUMMARY

[0006] The present application has been made to solve the problem of providing a digital isolator capable of improving insulation breakdown resistance.

[0007] The digital isolator of the embodiment includes a first electrode, a first insulating portion, a second electrode, a second insulating portion, and a first dielectric portion. The first insulating portion is provided below the first electrode. The second electrode is provided below the first insulating portion. The second insulating portion is provided around the first electrode along a first face perpendicular to a first direction from the second electrode toward the first electrode. The first dielectric portion is provided between the first electrode and the second insulating portion along a second direction along the first face, in contact with the first electrode. The relative dielectric constant of the first dielectric portion is higher than the relative dielectric constant of the first insulating portion. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is a cross-sectional view showing a digital isolator of a first embodiment.

[0009] Figure 2 is a cross-sectional view showing a digital isolator of a second embodiment.

[0010] Figure 3 is a cross-sectional view showing a digital isolator of a third embodiment.

[0011] EXPLANATION OF REFERENCE NUMERALS

[0012] 11 first electrode, 12 second electrode, 21 first insulating portion, 22 second insulating portion, 23 third insulating portion, 28 upper insulating portion, 31 first dielectric portion, 32 second dielectric portion, 33 first intermediate dielectric portion, 34 second intermediate dielectric portion, 36 first dielectric layer, 37 second dielectric layer, 41 to 43 insulating layer, 50 electrically conductive body, 51 first electrically conductive portion, 52 second electrically conductive portion, 53 third electrically conductive portion, 60 connecting portion, 100, 200, 300 digital isolator Detailed Implementation

[0013] Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings.

[0014] The accompanying drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of the size between parts, etc., may not be the same as in reality. Even when showing the same parts, there may be cases where the dimensions and ratios of each other are represented differently according to the accompanying drawings.

[0015] In this application specification and figures, elements that are the same as those already described are labeled with the same reference numerals and detailed descriptions are omitted where appropriate.

[0016] (First Implementation)

[0017] Figure 1 This is a cross-sectional view showing the digital isolator of the first embodiment.

[0018] like Figure 1 As shown, the digital isolator 100 of the first embodiment includes a first electrode 11, a second electrode 12, a first insulating portion 21, a second insulating portion 22, a third insulating portion 23, an upper insulating portion 28, a first dielectric portion 31, a second dielectric portion 32, a first intermediate dielectric portion 33, a second intermediate dielectric portion 34, insulating layers 41 to 43, and a conductor 50.

[0019] In the description of the implementation, an XYZ orthogonal coordinate system is used. The direction from the second electrode 12 toward the first electrode 11 is defined as the Z direction (first direction). The two directions perpendicular to and orthogonal to the Z direction are defined as the X direction (second direction) and the Y direction (third direction). Furthermore, for illustrative purposes, the direction from the second electrode 12 toward the first electrode 11 is referred to as "up," and its opposite direction as "down." These directions are based on the relative positional relationship between the first electrode 11 and the second electrode 12 and are independent of the direction of gravity.

[0020] A first insulating portion 21 is disposed below the first electrode 11. A second electrode 12 is disposed below the first insulating portion 21. That is, the first insulating portion 21 is disposed between the first electrode 11 and the second electrode 12 in the Z direction. Thus, the first electrode 11 and the second electrode 12 are electrically isolated from each other. The first electrode 11 and the second electrode 12 are opposite to each other in the Z direction. At least a portion of the second electrode 12 overlaps with at least a portion of the first electrode 11 in the Z direction.

[0021] The second insulating portion 22 is disposed around the first electrode 11 along the XY plane (first surface) perpendicular to the Z direction. The third insulating portion 23 is disposed around the second electrode 12 along the XY plane (second surface) perpendicular to the Z direction.

[0022] The first dielectric portion 31 is provided between the first electrode 11 and the second insulating portion 22 in the X direction and the Y direction. The first dielectric portion 31 is in contact with the first electrode 11. The relative dielectric constant of the first dielectric portion 31 is higher than the relative dielectric constant of the first insulating portion 21.

[0023] The second dielectric portion 32 is provided between the second electrode 12 and the third insulating portion 23 in the X direction and the Y direction. The second dielectric portion 32 is in contact with the second electrode 12. The relative dielectric constant of the second dielectric portion 32 is higher than the relative dielectric constant of the first insulating portion 21.

[0024] In this example, the first electrode 11 and the second electrode 12 are coils provided in a spiral shape along the X-Y plane. That is, the digital isolator 100 is a magnetic coupling type digital isolator. The first electrode 11 and the second electrode 12 can also be planar electrodes along the X-Y plane. That is, the digital isolator 100 can also be a capacitive coupling type digital isolator.

[0025] A first intermediate dielectric portion 33 is provided along the X-Y plane between the coils of the first electrode 11. The relative dielectric constant of the first intermediate dielectric portion 33 is higher than the relative dielectric constant of the first insulating portion 21. A second intermediate dielectric portion 34 is provided along the X-Y plane between the coils of the second electrode 12. The relative dielectric constant of the second intermediate dielectric portion 34 is higher than the relative dielectric constant of the first insulating portion 21.

[0026] An insulating layer 41 is provided on the first electrode 11. The insulating layer 41 is provided between the first electrode 11 and the upper insulating portion 28 in the Z direction. The insulating layer 41 is, for example, in contact with the first electrode 11. An insulating layer 42 is provided under the first electrode 11. The insulating layer 42 is provided between the first electrode 11 and the first insulating portion 21 in the Z direction. The insulating layer 42 is, for example, in contact with the first electrode 11. An insulating layer 43 is provided on the second electrode 12. The insulating layer 43 is provided between the second electrode 12 and the first insulating portion 21 in the Z direction. The insulating layer 43 is, for example, in contact with the second electrode 12.

[0027] A conductive body 50 is provided in the X direction at a position separate from the first electrode 11 and the second electrode 12. The conductive body 50 is, for example, provided around the first electrode 11 and the second electrode 12 along the first face. In this example, the conductive body 50 includes a first conductive portion 51, a second conductive portion 52, and a third conductive portion 53.

[0028] The first conductive portion 51 is provided at a position separated from the first electrode 11 in the X direction. In the X direction, the second insulating portion 22 and the first dielectric portion 31 are located between the first conductive portion 51 and the first electrode 11. The second insulating portion 22 is in contact with the first conductive portion 51. The second conductive portion 52 is provided below the first conductive portion 51. The first insulating portion 21 is in contact with the second conductive portion 52. The third conductive portion 53 is provided below the second conductive portion 52. The third conductive portion 53 is provided at a position separated from the second electrode 12 in the X direction. In the X direction, the third insulating portion 23 and the second dielectric portion 32 are located between the third conductive portion 53 and the second electrode 12. The third insulating portion 23 is in contact with the third conductive portion 53.

[0029] A portion of the insulating layer 41 is provided on the first conductive portion 51. A portion of the insulating layer 41 is in contact with the first conductive portion 51, for example. A portion of the insulating layer 42 is provided around the bottom of the first conductive portion 51 along the X-Y plane. A portion of the insulating layer 42 is in contact with the first conductive portion 51, for example. A portion of the insulating layer 43 is provided around the bottom of the second conductive portion 52 along the X-Y plane. A portion of the insulating layer 43 is in contact with the second conductive portion 52 and the third conductive portion 53, for example.

[0030] Both ends of the first electrode 11 (both ends of the coil) are electrically connected to a first circuit not shown via a wiring. Both ends of the second electrode 12 (both ends of the coil) are electrically connected to a second circuit not shown via a wiring.

[0031] In this example, the second electrode 12 is electrically connected to the second circuit via the conductive body 50. That is, in this example, the conductive body 50 functions as an electrode for leading the wiring of the second electrode 12 upward. The second electrode 12 is electrically connected to the conductive body 50 via the third conductive portion 53, for example. The conductive body 50 is electrically connected to the second circuit via the connection portion 60 in contact with the first conductive portion 51 above the first conductive portion 51, for example. Further, the conductive body 50 can not be electrically connected to the second electrode 12. The conductive body 50 can be an electrode of a component adjacent to the digital isolator 100, a circuit, or the like, for example.

[0032] An upper insulating portion 28 is provided above the first electrode 11 and the conductive body 50. More specifically, the upper insulating portion 28 is provided above the first electrode 11, the first intermediate dielectric portion 33, the first dielectric portion 31, the second insulating portion 22, and the first conductive portion 51. The connection portion 60 is provided inside the upper insulating portion 28.

[0033] One of the first circuit and the second circuit is used as a transmission circuit. The other of the first circuit and the second circuit is used as a reception circuit. Here, a case where the first circuit is the transmission circuit and the second circuit is the reception circuit is described.

[0034] The first circuit sends a signal (current) of a waveform suitable for transmission to the first electrode 11. When the current flows through the first electrode 11, a magnetic field passing through the inside of the helical first electrode 11 is generated. At least a part of the first electrode 11 is arranged in parallel with at least a part of the second electrode 12 in the Z direction. A part of the generated magnetic force line passes through the inside of the second electrode 12. Due to the change in the magnetic field of the inside of the second electrode 12, an induced electromotive force is generated in the second electrode 12, and a current flows through the second electrode 12. The second circuit detects the current flowing through the second electrode 12, and generates a signal corresponding to the detection result. Thus, in a state in which the current is cut off (insulated) between the first electrode 11 and the second electrode 12, a signal or energy is transmitted.

[0035] An example of the material of each constituent element of the digital isolator 100 will be described.

[0036] The first electrode 11, the second electrode 12, and the electrically conductive body 50 contain, for example, a metal. The first electrode 11, the second electrode 12, and the electrically conductive body 50 contain, for example, at least one kind of metal selected from the group consisting of copper and aluminum.

[0037] The first insulating portion 21, the second insulating portion 22, the third insulating portion 23, and the upper insulating portion 28 contain silicon and oxygen. The first insulating portion 21, the second insulating portion 22, the third insulating portion 23, and the upper insulating portion 28 contain, for example, silicon oxide. The first insulating portion 21, the second insulating portion 22, the third insulating portion 23, and the upper insulating portion 28 can further contain carbon or nitrogen.

[0038] The insulating layers 41 to 43 contain silicon and nitrogen. The insulating layers 41 to 43 contain, for example, silicon nitride. The insulating layers 41 to 43 can further contain carbon.

[0039] The first dielectric portion 31, the second dielectric portion 32, the first intermediate dielectric portion 33, and the second intermediate dielectric portion 34 contain, for example, silicon and nitrogen. The first dielectric portion 31, the second dielectric portion 32, the first intermediate dielectric portion 33, and the second intermediate dielectric portion 34 contain, for example, silicon nitride. The first dielectric portion 31, the second dielectric portion 32, the first intermediate dielectric portion 33, and the second intermediate dielectric portion 34 can further contain carbon.

[0040] The relative dielectric constant of the first dielectric portion 31 is higher than the relative dielectric constant of the first insulating portion 21. The relative dielectric constant of the first dielectric portion 31 is, for example, higher than the relative dielectric constant of the second insulating portion 22. The relative dielectric constant of the second dielectric portion 32 is higher than the relative dielectric constant of the first insulating portion 21. The relative dielectric constant of the second dielectric portion 32 is, for example, higher than the relative dielectric constant of the third insulating portion 23. The relative dielectric constant of the first dielectric portion 31 and the relative dielectric constant of the second dielectric portion 32 are, for example, the same. The relative dielectric constant of the first dielectric portion 31 and the relative dielectric constant of the second dielectric portion 32 can also be different.

[0041] The relative dielectric constant of the first intermediate dielectric portion 33 is higher than the relative dielectric constant of the first insulating portion 21. The relative dielectric constant of the first intermediate dielectric portion 33 and the relative dielectric constant of the first dielectric portion 31 are, for example, the same. The relative dielectric constant of the first intermediate dielectric portion 33 and the relative dielectric constant of the first dielectric portion 31 can also be different. The relative dielectric constant of the second intermediate dielectric portion 34 is higher than the relative dielectric constant of the first insulating portion 21. The relative dielectric constant of the second intermediate dielectric portion 34 and the relative dielectric constant of the second dielectric portion 32 are, for example, the same. The relative dielectric constant of the second intermediate dielectric portion 34 and the relative dielectric constant of the second dielectric portion 32 can also be different. The relative dielectric constant of the first intermediate dielectric portion 33 and the relative dielectric constant of the second intermediate dielectric portion 34 are, for example, the same. The relative dielectric constant of the first intermediate dielectric portion 33 and the relative dielectric constant of the second intermediate dielectric portion 34 can also be different.

[0042] The width W1 of the second insulating portion 22 in the X direction is, for example, greater than the width W2 of the first dielectric portion 31 in the X direction. The width W2 is, for example, less than half the distance in the X direction between the first electrode 11 and the conductive body 50 (the first conductive portion 51). The width W3 of the third insulating portion 23 in the X direction is, for example, greater than the width W4 of the second dielectric portion 32 in the X direction. The width W4 is, for example, less than half the distance in the X direction between the second electrode 12 and the conductive body 50 (the third conductive portion 53). The width W2 and the width W4 are, for example, the same. The width W2 and the width W4 can also be different.

[0043] The thickness T1 of the first dielectric portion 31 in the Z direction is, for example, the same as the thickness T2 of the first electrode 11 in the Z direction. The thickness T1 is, for example, the same as the thickness T3 of the second insulating portion 22 in the Z direction. The thickness T1 is, for example, the same as the thickness T4 of the first intermediate dielectric portion 33 in the Z direction. The thickness T5 of the second dielectric portion 32 in the Z direction is, for example, the same as the thickness T6 of the second electrode 12 in the Z direction. The thickness T5 is, for example, the same as the thickness T7 of the third insulating portion 23 in the Z direction. The thickness T5 is, for example, the same as the thickness T8 of the second intermediate dielectric portion 34 in the Z direction.

[0044] The following describes the effects of the first embodiment.

[0045] When a signal is transmitted between the first electrode 11 and the second electrode 12, a potential difference is generated between the first electrode 11 and the second electrode 12. As a result, electric field concentration occurs in the vicinity of the lower end of the first electrode 11 and in the vicinity of the upper end of the second electrode 12, and insulation breakdown can occur. In addition, due to the driving voltage of the first circuit and the second circuit, the potential difference between the first circuit and the second circuit, an unintended high voltage or surge generated in the first circuit and / or the second circuit, or the like, electric field concentration can occur in the vicinity of the lower end of the first electrode 11 and in the vicinity of the upper end of the second electrode 12, and insulation breakdown can occur.

[0046] As a method of improving the insulation breakdown resistance, for example, increasing the thickness of the first insulating portion 21 in the Z direction is considered. However, if the thickness of the first insulating portion 21 in the Z direction is increased, the warping of a substrate (for example, a wafer or the like) on which the digital isolator is formed can increase, or the manufacturing cost can increase in the manufacturing process.

[0047] In contrast, in the digital isolator 100 of the first embodiment, by providing the first dielectric portion 31 having a relatively high relative dielectric constant compared to the first insulating portion 21 adjacent to the first electrode 11, the electric field lines between the first electrode 11 and the second electrode 12 can be drawn to the first dielectric portion 31 side. As a result, the electric field concentration in the vicinity of the lower end of the first electrode 11 can be alleviated, and the insulation breakdown resistance can be improved without increasing the thickness of the first insulating portion 21 in the Z direction.

[0048] In addition, by providing both the second insulating portion 22 and the first dielectric portion 31 between the first electrode 11 and the conductive body 50, the insulation breakdown resistance can be improved by the second insulating portion 22 having excellent withstand voltage, for example, compared to a case where the entire region between the first electrode 11 and the conductive body 50 is provided as the first dielectric portion 31. In addition, by making the width W1 of the second insulating portion 22 in the X direction larger than the width W2 of the first dielectric portion 31 in the X direction, the insulation breakdown resistance can be further improved by the second insulating portion 22 having excellent withstand voltage.

[0049] In addition, by providing the first intermediate dielectric portion 33 having a relatively high relative dielectric constant compared to the first insulating portion 21 between the coils of the first electrode 11, the electric field lines between the first electrode 11 and the second electrode 12 can be drawn to the first intermediate dielectric portion 33 side. As a result, the electric field concentration in the vicinity of the lower end of the first electrode 11 can be further alleviated, and the insulation breakdown resistance can be further improved.

[0050] Likewise, by providing the second dielectric portion 32 having a high relative dielectric constant compared to the first insulating portion 21 adjacent to the second electrode 12, the electric field lines between the first electrode 11 and the second electrode 12 can be drawn to the side of the second dielectric portion 32. Thus, the concentration of the electric field near the upper end of the second electrode 12 can be alleviated, and the insulation breakdown resistance can be improved without increasing the thickness of the first insulating portion 21 in the Z direction.

[0051] Further, by providing both the third insulating portion 23 and the second dielectric portion 32 between the second electrode 12 and the electrically conductive body 50, the insulation breakdown resistance can be improved by the third insulating portion 23 having excellent withstand voltage, for example, compared to the case where the entire region between the second electrode 12 and the electrically conductive body 50 is provided as the second dielectric portion 32. Further, by making the width W3 of the third insulating portion 23 in the X direction larger than the width W4 of the second dielectric portion 32 in the X direction, the insulation breakdown resistance can be further improved by the third insulating portion 23 having excellent withstand voltage.

[0052] Further, by providing the second intermediate dielectric portion 34 having a high relative dielectric constant compared to the first insulating portion 21 between the coils of the second electrode 12, the electric field lines between the first electrode 11 and the second electrode 12 can be drawn to the side of the second intermediate dielectric portion 34. Thus, the concentration of the electric field near the upper end of the second electrode 12 can be further alleviated, and the insulation breakdown resistance can be further improved.

[0053] (Second Embodiment)

[0054] Figure 2 is a cross-sectional view of a digital isolator of the second embodiment.

[0055] As Figure 2 shown, the digital isolator 200 of the second embodiment includes the first electrode 11, the second electrode 12, the first insulating portion 21, the second insulating portion 22, the third insulating portion 23, the upper insulating portion 28, the first dielectric layer 36, the second dielectric layer 37, the insulating layers 41 to 43, and the electrically conductive body 50.

[0056] The digital isolator 200 of the second embodiment is the same as the digital isolator 100 of the first embodiment except that the first dielectric portion 31, the second dielectric portion 32, the first intermediate dielectric portion 33, and the second intermediate dielectric portion 34 are not provided, and the first dielectric layer 36 and the second dielectric layer 37 are provided. The same structures are omitted from the description.

[0057] The second insulating portion 22 is provided between the first electrode 11 and the conductive body 50 over the entire area. Also, the second insulating portion 22 is provided between the coils of the first electrode 11. The third insulating portion 23 is provided between the second electrode 12 and the conductive body 50 over the entire area. Also, the third insulating portion 23 is provided between the coils of the second electrode 12.

[0058] The first dielectric layer 36 and the second dielectric layer 37 are provided inside the upper insulating portion 28. The first dielectric layer 36 is provided on one of the first electrode 11 and the conductive body 50. The second dielectric layer 37 is provided on the other of the first electrode 11 and the conductive body 50. In this example, the first dielectric layer 36 is provided on the first electrode 11, and the second dielectric layer 37 is provided on the conductive body 50.

[0059] The first dielectric layer 36 and the second dielectric layer 37 contain, for example, silicon and nitrogen. The first dielectric layer 36 and the second dielectric layer 37 contain, for example, silicon nitride. The first dielectric layer 36 and the second dielectric layer 37 can further contain carbon.

[0060] The relative dielectric constant of the first dielectric layer 36 is higher than the relative dielectric constant of the second insulating portion 22. The relative dielectric constant of the first dielectric layer 36 is, for example, higher than the relative dielectric constant of the upper insulating portion 28. The relative dielectric constant of the second dielectric layer 37 is higher than the relative dielectric constant of the second insulating portion 22. The relative dielectric constant of the second dielectric layer 37 is, for example, higher than the relative dielectric constant of the upper insulating portion 28. The relative dielectric constant of the first dielectric layer 36 and the relative dielectric constant of the second dielectric layer 37 are, for example, the same. The relative dielectric constant of the first dielectric layer 36 and the relative dielectric constant of the second dielectric layer 37 can be different.

[0061] The width W11 of the first dielectric layer 36 in the X direction is, for example, the same as the width W13 of the coil portion of the first electrode 11 in the X direction. The width W11 can also be greater than the width W13. The width W12 of the second dielectric layer 37 in the X direction is, for example, the same as the width W14 of the first conductive portion 51 in the X direction. The width W12 can also be greater than the width W14.

[0062] The thickness T11 of the first dielectric layer 36 in the Z direction is, for example, equal to or less than the thickness T13 of the upper insulating portion 28 in the Z direction. The thickness T11 is, for example, equal to the thickness T2 of the first electrode 11 in the Z direction. The thickness T11 can be greater than the thickness T2, or can be less than the thickness T2. The thickness T12 of the second dielectric layer 37 in the Z direction is, for example, equal to or less than the thickness T13. The thickness T12 is, for example, equal to the thickness T2. The thickness T12 can be greater than the thickness T2, or can be less than the thickness T2.

[0063] Next, the effects of the second embodiment will be described.

[0064] In a case where the conductive body 50 is disposed in the vicinity of the first electrode 11 and the second electrode 12, a potential difference occurs between the first electrode 11 and the conductive body 50 when a signal is transmitted between the first electrode 11 and the second electrode 12. Thus, electric field concentration occurs in the vicinity of the side end of the first electrode 11 and the side end of the conductive body 50, and insulation breakdown can occur. In addition, due to the driving voltage of the first circuit and the second circuit, the potential difference between the first circuit and the second circuit, an unintended high voltage or a surge generated in the first circuit and / or the second circuit, and the like, electric field concentration can occur in the vicinity of the side end of the first electrode 11 and the side end of the conductive body 50, and insulation breakdown can occur.

[0065] As a method of improving the insulation breakdown resistance, for example, it is considered to increase the distance between the first electrode 11 and the conductive body 50. However, if the distance between the first electrode 11 and the conductive body 50 is increased, the chip area can increase. If the chip area increases, the manufacturing cost can increase.

[0066] In contrast, in the digital isolator 200 of the second embodiment, by providing the first dielectric layer 36 having a higher relative dielectric constant than the second insulating portion 22 on one of the first electrode 11 and the conductive body 50, the electric field lines between the first electrode 11 and the conductive body 50 can be drawn to the side of the first dielectric layer 36. Thus, the electric field concentration in the vicinity of the side end of one of the first electrode 11 and the conductive body 50 can be alleviated, and the insulation breakdown resistance can be improved without increasing the chip area.

[0067] Similarly, by providing the second dielectric layer 37 having a higher relative dielectric constant than the second insulating portion 22 on the other of the first electrode 11 and the conductive body 50, the electric field lines between the first electrode 11 and the conductive body 50 can be drawn to the side of the second dielectric layer 37. Thus, the electric field concentration in the vicinity of the side end of the other of the first electrode 11 and the conductive body 50 can be alleviated, and the insulation breakdown resistance can be improved without increasing the chip area.

[0068] Further, in a case where the conductive body 50 and the second electrode 12 are not electrically connected, a potential difference can occur between the second electrode 12 and the conductive body 50. In this case, for example, a dielectric layer can be provided below the second electrode 12 and below the third conductive portion 53, respectively. In a case where these dielectric layers are provided, the relative dielectric constant of these dielectric layers is higher than the relative dielectric constant of the third insulating portion 23. Thus, similarly to the case where the first dielectric layer 36 and the second dielectric layer 37 are provided as described above, the electric field concentration between the second electrode 12 and the conductive body 50 can be alleviated, and the insulation breakdown resistance can be improved without increasing the chip area.

[0069] (third embodiment)

[0070] Figure 3 is a cross-sectional view showing a digital isolator of the third embodiment.

[0071] As shown in Figure 3 , the digital isolator 300 of the third embodiment has the first electrode 11, the second electrode 12, the first insulating portion 21, the second insulating portion 22, the third insulating portion 23, the upper insulating portion 28, the first dielectric portion 31, the second dielectric portion 32, the first intermediate dielectric portion 33, the second intermediate dielectric portion 34, the first dielectric layer 36, the second dielectric layer 37, the insulating layers 41 to 43, and the electrically conductive body 50.

[0072] In the digital isolator 300 of the third embodiment, the first dielectric layer 36 and the second dielectric layer 37 of the digital isolator 200 of the second embodiment are provided in addition to the first dielectric portion 31, the second dielectric portion 32, the first intermediate dielectric portion 33, and the second intermediate dielectric portion 34 of the digital isolator 100 of the first embodiment. The structures of the respective portions are the same as those of the first embodiment and the second embodiment, and thus the description is omitted.

[0073] In the digital isolator 300 of the third embodiment, by providing the first dielectric portion 31, the second dielectric portion 32, the first intermediate dielectric portion 33, and the second intermediate dielectric portion 34, the electric field concentration near the lower end of the first electrode 11 and near the upper end of the second electrode 12 can be moderated, and the insulation breakdown resistance can be improved without increasing the thickness of the first insulating portion 21 in the Z direction.

[0074] In addition, in the digital isolator 300 of the third embodiment, by providing the first dielectric layer 36 and the second dielectric layer 37, the electric field concentration near the side end of the first electrode 11 and near the side end of the electrically conductive body 50 can be moderated, and the insulation breakdown resistance can be improved without increasing the chip area.

[0075] As described above, according to the embodiments, the digital isolator capable of improving the insulation breakdown resistance is provided.

[0076] The above illustrates several embodiments of the present application, but these embodiments are suggested as examples and are not intended to limit the scope of the application. These new embodiments can be implemented in other various ways, and various omissions, substitutions, changes, and the like can be made within the scope of the gist of the application. These embodiments and their modified examples are included in the scope or gist of the application, and are included in the scope of the application and its equivalents described in the claims. In addition, the aforementioned embodiments can be implemented in combination with each other.

Claims

1. A digital isolator comprising: a first electrode; a first insulating portion provided below the first electrode; a second electrode provided below the first insulating portion; a second insulating portion provided around the first electrode along a first face perpendicular to a first direction from the second electrode toward the first electrode; and a first dielectric portion provided between the first electrode and the second insulating portion along a second direction along the first face and in contact with the first electrode, a relative dielectric constant of the first dielectric portion being higher than a relative dielectric constant of the first insulating portion, the first electrode being located between a first insulating layer containing silicon and nitrogen and a second insulating layer containing silicon and nitrogen in the first direction.

2. The digital isolator according to claim 1, wherein a width of the second direction of the second insulating portion is larger than a width of the second direction of the first dielectric portion.

3. The digital isolator according to claim 1 or 2, wherein the first electrode is a coil provided in a spiral shape along the first face, the digital isolator further comprising a first intermediate dielectric portion provided between the coils along the first face, a relative dielectric constant of the first intermediate dielectric portion being higher than the relative dielectric constant of the first insulating portion. Further comprising: a third insulating portion provided around the second electrode along a second face perpendicular to the first direction; and a second dielectric portion provided between the second electrode and the third insulating portion in the second direction and in contact with the second electrode, a relative dielectric constant of the second dielectric portion being higher than the relative dielectric constant of the first insulating portion.

5. The digital isolator according to claim 4, wherein a width of the second direction of the third insulating portion is larger than a width of the second direction of the second dielectric portion.

6. The digital isolator according to claim 4 or 5, wherein the second electrode is a coil provided in a spiral shape along the second face, the digital isolator further comprising a second intermediate dielectric portion provided between the coils along the second face, a relative dielectric constant of the second intermediate dielectric portion being higher than the relative dielectric constant of the first insulating portion.

7. A digital isolator comprising: a first electrode; a first insulating portion provided below the first electrode; a second electrode provided below the first insulating portion; a conductor provided at a position separated from the first electrode in a second direction perpendicular to a first direction from the second electrode toward the first electrode; a second insulating portion provided between the first electrode and the conductor in the second direction; an upper insulating portion provided above the first electrode and the conductor; and a first dielectric layer provided inside the upper insulating portion above one of the first electrode and the conductor, a relative dielectric constant of the first dielectric layer being higher than a relative dielectric constant of the second insulating portion, the first electrode being located between a first insulating layer containing silicon and nitrogen and a second insulating layer containing silicon and nitrogen in the first direction. ​ ​ ​ ​ ​ ​ ​ ​ 4. The digital isolator of claim 1, wherein, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 8. The digital isolator of claim 7, wherein, a second dielectric layer is further provided, the second dielectric layer being disposed inside the upper insulating portion and on the other of the first electrode and the conductor, a relative dielectric constant of the second dielectric layer is higher than a relative dielectric constant of the second insulating portion.

Images