Three-dimensional inductor and electronic device

Abstract

The present invention provides a three-dimensional inductor and electronic device. The three-dimensional inductor comprises: a substrate having a first surface and a second surface facing each other; a coil formed by sequentially connecting a plurality of first and second conductive wires, wherein the first conductive wires extend through the substrate and the second conductive wires extend along the first and second surfaces; and a magnetic core disposed within the substrate and surrounded or enclosed by the coil. The magnetic core comprises a plurality of first magnetic surfaces formed by lead zirconate titanate thin films, the first magnetic surfaces being parallel to the first conductive wires and forming a ring-shaped structure. In the present invention, the use of a thin film structure formed by coating the inner wall of an annular groove with lead zirconate titanate thin film as the magnetic core not only facilitates fabrication but also improves the inductance and quality factor of the three-dimensional inductor.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a three-dimensional inductor and an electronic device. Background Art

[0002] Inductors are one of the essential basic components in integrated circuits. They play an important role in switching power supplies and radio frequency circuits.

[0003] As integrated circuits become more integrated, the feature sizes of semiconductor devices will reach their physical limits. To further improve performance and integration, researchers are integrating chips in three dimensions. Compared to planar inductors, three-dimensional inductors occupy a smaller chip area, significantly improving packaging density and inductance density per unit area. However, existing three-dimensional inductors struggle to achieve both high inductance and a high quality factor. This also complicates the structural design, hindering their manufacture. Summary of the Invention

[0004] An object of the present invention is to provide a three-dimensional inductor and an electronic device to improve the performance of the three-dimensional inductor.

[0005] To solve the above technical problems, the present invention provides a three-dimensional inductor, comprising:

[0006] a substrate having a first surface and a second surface opposite to each other;

[0007] a coil formed by sequentially connecting a plurality of first conductive wires and a plurality of second conductive wires, wherein the first conductive wires penetrate the substrate and the second conductive wires extend along the first surface and the second surface;

[0008] A magnetic core is arranged in the substrate and surrounded or encircled by the coil, wherein the magnetic core includes a plurality of first magnetic surfaces formed by lead zirconate titanate films, wherein the first magnetic surfaces are parallel to the first conductive wire and the plurality of first magnetic surfaces form a ring structure.

[0009] Optionally, the coil is a straight spiral coil, and a plurality of the first magnetic conduction surfaces form a rectangular shape inside the coil.

[0010] Optionally, a meandering groove is formed in the substrate surrounded by the coil, the first magnetic surface covers the sidewalls of the meandering groove, and the meandering groove is filled with a first material layer.

[0011] Optionally, a rectangular groove is formed in the substrate surrounded by the coil, the first magnetic surface covers the sidewalls of the rectangular groove, and the rectangular groove is filled with a second material layer.

[0012] Optionally, the coil is a ring-shaped spiral coil, a groove is formed in the substrate surrounded by the coil, the first magnetic surface covers the sidewall of the groove, and the groove is filled with a third material layer.

[0013] Optionally, the coil is a ring-shaped spiral coil, a groove is formed in the substrate surrounded by the coil, the first magnetic surface covers the sidewall of the groove, and the groove is filled with a fourth material layer.

[0014] Optionally, the magnetic core further includes a second magnetic surface formed by the lead zirconate titanate film, the second magnetic surface is parallel to the second conductive wire, and the second magnetic surface covers the first surface of the substrate and / or the second surface of the substrate.

[0015] Optionally, the first magnetic surface and the second magnetic surface form at least one completely closed lead zirconate titanate thin film structure in the coil.

[0016] Optionally, the first surface and the second surface of the substrate are both covered with an isolation dielectric layer, the lead zirconate titanate film is arranged on the side of the isolation dielectric layer facing the substrate, and the second wire is arranged in the isolation dielectric layer or on the side of the isolation dielectric layer away from the substrate.

[0017] According to another aspect of the present invention, an electronic device is provided. The electronic device includes an integrated circuit. The integrated circuit includes the three-dimensional inductor as described above.

[0018] In summary, the coil of the three-dimensional inductor provided by the present invention is formed by connecting a plurality of first conductive wires extending through a substrate and a plurality of second conductive wires disposed on the first and second surfaces. The magnetic core is disposed within the substrate surrounded by the coil and includes a plurality of first magnetic surfaces parallel to the first conductive wires. The first magnetic surfaces are formed by a lead zirconate titanate film, and the plurality of first magnetic surfaces form a ring-shaped structure within the coil. In this three-dimensional inductor, the higher magnetic permeability of the lead zirconate titanate film compared to the substrate is utilized to increase the inductance of the three-dimensional inductor. The higher dielectric constant of the lead zirconate titanate film compared to the substrate is utilized to reduce eddy current losses. The thinner film structure is utilized to reduce core losses, thereby improving the quality factor. Furthermore, compared to using a similar solid structure as a magnetic core, using a ring-shaped thin film structure formed by the lead zirconate titanate film as the magnetic core is not only easier to manufacture, but also simultaneously improves the inductance and quality factor of the three-dimensional inductor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Those skilled in the art should understand that the drawings are provided for a better understanding of the present invention, but do not constitute any limitation on the scope of the present invention.

[0020] Figure 1a is a schematic cross-sectional view of a three-dimensional inductor provided in Example 1; Figure 1bFIG. 1 is a schematic top view of a three-dimensional inductor provided in the first embodiment.

[0021] Figure 2a is a cross-sectional schematic diagram of the three-dimensional inductor provided in Example 2; Figure 2b FIG. 1 is a schematic top view of a three-dimensional inductor provided in the second embodiment.

[0022] Figure 3 4 is a cross-sectional schematic diagram of a three-dimensional inductor provided in the second embodiment.

[0023] Figure 4 FIG. 4 is a cross-sectional schematic diagram of another three-dimensional inductor provided in the second embodiment.

[0024] Figure 5 Schematic diagram of the structure of a three-dimensional inductor provided in Example 3.

[0025] Figure 6 Schematic diagram of another three-dimensional inductor provided in the third embodiment.

[0026] Figure 7 Schematic diagram of the structure of another three-dimensional inductor provided in the third embodiment.

[0027] Figure 8 Schematic diagram of the structure of the three-dimensional inductor provided in the fourth embodiment.

[0028] Figure 9 Schematic diagram of the structure of the three-dimensional inductor provided in the fifth embodiment.

[0029] In the attached figure:

[0030] 10-substrate; 10a-first surface; 10b-second surface; 11-zigzag groove; 12-middle area; 13-rectangular groove; 14-annular groove; 15-groove; 22-lead zirconate titanate film; 23-first material layer; 31-through hole; 32-first dielectric layer; 33-first conductor; 34-second conductor; L2-length of the zigzag groove; L1-length of the coil. DETAILED DESCRIPTION

[0031] To make the objects, advantages, and features of the present invention more clearly apparent, the present invention is further described below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale. They are only used to conveniently and clearly assist in illustrating the purposes of the embodiments of the present invention. In addition, the structures shown in the drawings are often part of the actual structure. In particular, different drawings may need to illustrate different focuses and sometimes use different scales.

[0032] As used in the present invention, the singular forms "a", "an", and "the" include plural objects, the term "or" is generally used to include the meaning of "and / or", the term "several" is generally used to include the meaning of "at least one", and the term "at least two" is generally used to include the meaning of "two or more". In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features specified as "first", "second", and "third" may explicitly or implicitly include one or at least two of the features, unless the content clearly indicates otherwise.

[0033] Example 1

[0034] Figure 1a is a schematic cross-sectional view of a three-dimensional inductor provided in Example 1; Figure 1b FIG. 1 is a schematic top view of a three-dimensional inductor provided in the first embodiment.

[0035] like Figure 1a and 1b As shown, the three-dimensional inductor provided in this embodiment includes a substrate 10, a coil, and a magnetic core. The substrate 10 has a first surface 10a and a second surface 10b opposite each other. The coil is formed by sequentially connecting a plurality of first conductive wires 33 and a plurality of second conductive wires 34. The first conductive wires 33 penetrate the substrate 10, and the second conductive wires 34 extend along the first surface 10a and the second surface 10b. The magnetic core is disposed within the substrate 10 surrounded by the coil and includes a plurality of first magnetic surfaces formed by lead zirconate titanate thin films 22. The first magnetic surfaces are parallel to the first conductive wires 33 and form a ring structure.

[0036] The substrate 10 may be any suitable base material known to those skilled in the art, for example, at least one of the following materials: silicon, glass, ceramic, gallium arsenide, gallium nitride, or silicon carbide. In this embodiment, the substrate 10 is made of silicon for illustration.

[0037] Please continue to refer to Figure 1aThe substrate 10 includes a first surface 10a and a second surface 10b that are opposite to each other. In this embodiment, each turn of the coil can be rectangular (wound into a rectangle) and includes a first conductive wire 33 and a second conductive wire 34. The first conductive wire 33 passes through the substrate 10 and is disposed in a through hole 31 of the substrate 10. The second conductive wire 34 is disposed on the first surface 10a and the second surface 10b, i.e., parallel to the surface of the substrate 10, and together with the two first conductive wires 33, forms a coil turn. Several turns of the rectangular coil are connected and extended along the surface of the substrate 10 to form a strip-shaped inductor coil (a straight spiral coil). A larger aspect ratio of the first conductive wire 33 (through hole 31) is more conducive to improving the inductance of the three-dimensional inductor, but is not conducive to improving its quality factor. A larger spacing between each turn of the coil is more conducive to improving the quality factor of the three-dimensional inductor, but is not conducive to improving its inductance. Increasing the number of turns of the coil is conducive to increasing the inductance of the three-dimensional inductor, but is not conducive to improving its quality factor. In addition, taking the example that the first surface 10a can be the front surface of the substrate 10 and the second surface 10b can be the back surface of the substrate 10, two leads of the coil are further provided on the first surface 10a and connected to the first wire 33 for electrically leading out the three-dimensional inductor.

[0038] Specifically, the first and second conductors 33, 34 can both be made of a metal with low resistivity, thereby reducing the coil resistance and improving the quality factor of the three-dimensional inductor. In this embodiment, the first and second conductors 33, 34 are both made of copper or a copper alloy, and the coil can have four turns. Both the first and second surfaces 10a, 10b are covered with an isolation dielectric layer, and the second conductor 34 is disposed within the isolation dielectric layer or on the side of the isolation dielectric layer away from the substrate 10. The isolation dielectric layer can be made of, but is not limited to, silicon oxide.

[0039] Please continue to refer to Figure 1a A meandering groove 11 is provided in the substrate 10 around which the coil is wound. The meandering groove 11 can be provided in the middle of the coil, and its sidewalls in the same direction are as far as possible from the first conductive wire 33 or the second conductive wire 34. In addition, the sidewalls of the meandering groove 11 are parallel to the first conductive wire 33. In one embodiment, the meandering groove 11 passes through the substrate 10, that is, the top surface and the bottom surface of the meandering groove 11 can be flush with the first surface 10a and the second surface 10b of the substrate 10, respectively. In addition, please refer to Figure 1b The length L2 of the meandering groove can be as close as possible to the length L1 of the coil, so as to save the area of ​​the substrate 10 while ensuring the performance of the three-dimensional inductor.

[0040] The sidewalls of the meandering groove 11 are covered with a lead zirconate titanate film 22, and the annular film structure formed by the lead zirconate titanate film 22 constitutes the magnetic core of the three-dimensional inductor. Figure 1bThe zigzag groove 11 has four side surfaces in both the length and width directions, and the lead zirconate titanate film 22 covers the side surfaces of the zigzag groove 11. That is, the three-dimensional inductor of this embodiment has eight first magnetic flux surfaces, forming two annular thin film structures. The higher magnetic permeability of the lead zirconate titanate film 22 compared to the substrate 10 is used to increase the inductance of the three-dimensional inductor, the higher dielectric constant of the lead zirconate titanate film 22 compared to the substrate 10 is used to reduce eddy current loss, and the thinner thickness of the film structure is used to reduce core loss, thereby improving the quality factor of the substrate 10. Moreover, compared to using a similar solid structure (such as the substrate 10 itself, air, or other materials) as the magnetic core, the use of the lead zirconate titanate film 22 structure is not only easier to implement in terms of manufacturing process, but also the inductance and quality factor of the three-dimensional inductor can be adjusted as needed by setting the shape and size of the film structure.

[0041] Specific methods for adjusting the inductance and quality factor of the three-dimensional inductor as needed include: increasing the thickness of the lead zirconate titanate film 22 to increase the inductance of the three-dimensional inductor and reduce its quality factor; adjusting the composition of the lead zirconate titanate film 22 to increase its dielectric constant to simultaneously increase the inductance and quality factor of the three-dimensional inductor; increasing the distance between the lead zirconate titanate film 22 and the coil to simultaneously reduce the inductance and quality factor of the three-dimensional inductor; and increasing the aspect ratio of the meandering groove 11 to simultaneously increase the inductance and quality factor of the three-dimensional inductor. Of course, if the meandering groove 11 does not penetrate the substrate 10, the bottom surface of the meandering groove 11 can also be covered with the lead zirconate titanate film 22.

[0042] It should be noted that, since the magnetic core formed by the lead zirconate titanate film 22 can significantly increase the inductance value of the three-dimensional inductor, compared with conventional inductors, in this embodiment, the quality factor of the three-dimensional inductor can be increased by reducing the number of turns of the coil while ensuring the inductance value.

[0043] In addition, the zigzag groove 11 is filled with a first material layer 23, which covers the lead zirconate titanate film 22 and completely fills the zigzag groove 11. The first material layer 23 can be made of any dielectric material suitable for filling, including but not limited to polyimide.

[0044] Example 2

[0045] Figure 2a is a cross-sectional schematic diagram of the three-dimensional inductor provided in Example 2; Figure 2b FIG. 1 is a schematic top view of a three-dimensional inductor provided in the second embodiment.

[0046] like Figure 2a and 2bAs shown, the substrate 10, coil, and magnetic core of the three-dimensional inductor provided in this embodiment are substantially similar to those of the first embodiment. The difference lies in that the magnetic core provided in this embodiment includes a first magnetic surface similar to that of the first embodiment, and also includes a second magnetic surface. The second magnetic surface is parallel to the second conductive wire 34 and covers the middle region 12 of the meandering groove 11 on the first surface 10a and / or the second surface 10b. Similar to the first magnetic surface, the second magnetic surface is formed of a lead zirconate titanate thin film 22. The thickness of the lead zirconate titanate thin film 22 on the second magnetic surface can be the same as that of the lead zirconate titanate thin film 22 on the first magnetic surface.

[0047] like Figure 3 As shown, in some embodiments, the second magnetic surface may extend to cover the top surface or the bottom surface of the meandering groove 11 in addition to covering the middle region 12 of the meandering groove 11 .

[0048] like Figure 4 As shown, in some embodiments, the meandering groove 11 does not penetrate the second surface 10b of the substrate 10, and the lead zirconate titanate film 22 can cover the projection of the middle area 12 of the meandering groove 11 on the second surface 10b to serve as the second magnetic permeability surface.

[0049] In such Figure 2a In the preferred embodiment shown, compared with other unclosed magnetic cores, the first magnetic surface and the second magnetic surface form at least one completely closed lead zirconate titanate film 22 structure in the coil as a magnetic core, which has better inductance and quality factor.

[0050] Example 3

[0051] Figure 5 Schematic diagram of the structure of the three-dimensional inductor provided in the third embodiment.

[0052] like Figure 5 As shown, the substrate 10, coil, and magnetic core of the three-dimensional inductor provided in this embodiment are substantially similar to those of the first embodiment. The difference lies in that a rectangular groove 13 is provided within the substrate 10 surrounding the coil. A lead zirconate titanate film 22 covers the sidewalls of the rectangular groove 13, forming a first magnetic permeability surface that serves as the magnetic core of the three-dimensional inductor. The rectangular groove 13 has two side surfaces in both the length and width directions, forming a ring-shaped thin film structure.

[0053] like Figure 6 As shown, similar to the second embodiment, in some embodiments, a second magnetic surface is further provided on the top surface and / or bottom surface of the rectangular groove 13 , and the second magnetic surface is parallel to the second wire 34 and is formed by the lead zirconate titanate film 22 .

[0054] like Figure 7As shown, if the rectangular groove 13 does not penetrate the substrate 10 , the bottom wall of the rectangular groove 13 may be covered with a lead zirconate titanate film 22 as a part of the magnetic core.

[0055] Example 4

[0056] Figure 8 Schematic diagram of the structure of the three-dimensional inductor provided in the fourth embodiment.

[0057] like Figure 8 As shown, the substrate 10, coil, and magnetic core of the three-dimensional inductor provided in this embodiment are similar in principle to those of the aforementioned embodiment, but their structures differ. Each turn of the coil provided in this embodiment is the same rectangular shape as in the aforementioned embodiment, and includes a first conductive wire 33 and a second conductive wire 34. However, the coil is annular (annular spiral coil), for example, in the shape of a ring. Accordingly, an annular groove 14 is provided within the substrate 10 surrounding the coil. The sidewalls (or inner walls) of the annular groove 14 are covered with a lead zirconate titanate thin film 22 to form the magnetic core of the three-dimensional inductor, including a first magnetically conductive surface parallel to the first conductive wire 33.

[0058] In some examples, a plurality of arcuate grooves are provided in the substrate 10 surrounded by the coil, and the plurality of arcuate grooves form a ring structure provided in the coil. The side walls (or inner walls) of the arcuate grooves are covered with a lead zirconate titanate film 22 to form the magnetic core of the three-dimensional inductor.

[0059] Furthermore, in some examples, a second magnetic conducting surface parallel to the second conducting wire 34 may be further provided.

[0060] Example 5

[0061] Figure 9 Schematic diagram of the structure of the three-dimensional inductor provided in the fifth embodiment.

[0062] like Figure 9 As shown, the substrate 10, coil, and magnetic core of the three-dimensional inductor provided in this embodiment are similar in principle to those of the above-mentioned embodiment, but their structures differ. The coil provided in this embodiment is similar to the coil of the fourth embodiment. Each turn of the coil can be rectangular, formed by a first conductive wire 33 and a second conductive wire 34. The coil as a whole is annular (a toroidal spiral coil), for example, in the shape of a ring. However, unlike the fourth embodiment, the magnetic core of this embodiment is not located within the substrate 10 surrounded by the coil (not surrounded by each turn of the coil). Instead, it is located within the substrate 10 surrounded by the toroidal coil, meaning that the magnetic core is only surrounded by the entire coil. Specifically, a circular groove 15 is provided in the substrate 10. The sidewalls of the groove 15 are covered with a lead zirconate titanate thin film 22 to form the magnetic core of the three-dimensional inductor, namely, the first magnetic permeability plane parallel to the first conductive wire 33.

[0063] In addition, in some examples, the groove 15 may also be annular, that is, include two layers of lead zirconate titanate films 22 (first magnetic surface).

[0064] In some examples, a second magnetic conducting plane parallel to the second conductive line 34 may be further provided.

[0065] Example 6

[0066] Embodiment 6 provides a three-dimensional inductor.

[0067] The three-dimensional inductor provided in this embodiment includes a substrate, a coil, and a magnetic core. Its basic structure and basic principles are similar to those of the above-mentioned embodiment, but the difference is that the coil provided in this embodiment can be a coil of any suitable shape, and is not limited to the above-mentioned straight spiral coil and toroidal spiral coil. Accordingly, its groove can be any suitable shape that matches the shape of the coil, and its shape can be, for example, any one of an n-gon (n is greater than or equal to 3), a meander, a ring, an ellipse, or any combination of several, thereby forming a lead zirconate titanate thin film on the sidewall (or inner wall) of the groove to serve as the magnetic core of the three-dimensional inductor.

[0068] In addition, as mentioned above, it is also feasible to form a lead zirconate titanate thin film on the first surface and / or the second surface of the substrate as the second magnetic permeability surface to constitute a part of the magnetic core of the three-dimensional inductor.

[0069] Example 7

[0070] Embodiment 7 provides an electronic device, which includes an integrated circuit having a three-dimensional inductor as described above. The three-dimensional inductor can be integrated with other semiconductor devices of the integrated circuit on the same substrate, while ensuring excellent inductor performance (inductance value and quality factor) while achieving a high integration density (packaging density).

[0071] In summary, the coil of the three-dimensional inductor provided by the present invention is formed by connecting a plurality of first conductive wires extending through a substrate and second conductive wires disposed on the first and second surfaces. The magnetic core is disposed within the substrate surrounded by the coil and includes a plurality of first magnetic surfaces parallel to the first conductive wires. The first magnetic surfaces are formed by a lead zirconate titanate film, and the plurality of first magnetic surfaces form a ring-shaped structure within the coil. In this three-dimensional inductor, the higher magnetic permeability of the lead zirconate titanate film compared to the substrate is utilized to increase the inductance of the three-dimensional inductor. The higher dielectric constant of the lead zirconate titanate film compared to the substrate is utilized to reduce eddy current losses. The thinner film structure is utilized to reduce core losses, thereby improving the quality factor. Furthermore, compared to using a similar solid structure as a magnetic core, using a ring-shaped thin film structure formed by the lead zirconate titanate film as the magnetic core is not only easier to manufacture, but also simultaneously improves the inductance and quality factor of the three-dimensional inductor.

[0072] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A three-dimensional inductor, characterized in that: include: a substrate having a first surface and a second surface opposite to each other; a coil formed by sequentially connecting a plurality of first conductive wires and a plurality of second conductive wires, wherein the first conductive wires penetrate the substrate and the second conductive wires extend along the first surface and the second surface; A magnetic core is arranged in the substrate and surrounded or encircled by the coil, wherein the magnetic core includes a plurality of first magnetic surfaces formed by lead zirconate titanate films, wherein the first magnetic surfaces are parallel to the first conductive wire and the plurality of first magnetic surfaces form a ring structure.

2. The three-dimensional inductor according to claim 1, wherein: The coil is a straight spiral coil, and a plurality of the first magnetic conduction surfaces form a rectangular shape inside the coil.

3. The three-dimensional inductor according to claim 2, wherein: A meandering groove is formed in the substrate surrounded by the coil, the first magnetic surface covers the sidewall of the meandering groove, and the meandering groove is filled with a first material layer.

4. The three-dimensional inductor according to claim 2, wherein: A rectangular groove is formed in the substrate around which the coil is wound, the first magnetic surface covers the sidewalls of the rectangular groove, and the rectangular groove is filled with a second material layer.

5. The three-dimensional inductor according to claim 1, wherein: The coil is a ring-shaped spiral coil. A groove is formed in the substrate surrounded by the coil. The first magnetic surface covers the sidewall of the groove, and the groove is filled with a third material layer.

6. The three-dimensional inductor according to claim 1, wherein: The coil is a ring-shaped spiral coil. A groove is formed in the substrate surrounded by the coil. The first magnetic surface covers the sidewall of the groove, and the groove is filled with a fourth material layer.

7. The three-dimensional inductor according to any one of claims 1 to 6, characterized in that: The magnetic core further includes a second magnetic surface formed by the lead zirconate titanate film, the second magnetic surface is parallel to the second conducting wire, and the second magnetic surface covers the first surface of the substrate and / or the second surface of the substrate.

8. The three-dimensional inductor according to claim 7, wherein: The first magnetic surface and the second magnetic surface form at least one completely closed lead zirconate titanate thin film structure in the coil.

9. The three-dimensional inductor according to claim 1, wherein: The first surface and the second surface of the substrate are both covered with an isolation dielectric layer, the lead zirconate titanate film is arranged on the side of the isolation dielectric layer facing the substrate, and the second wire is arranged in the isolation dielectric layer or on the side of the isolation dielectric layer away from the substrate.

10. An electronic device, characterized in that: The electronic device includes an integrated circuit including the three-dimensional inductor according to any one of claims 1 to 9.

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