Bridge type inductor structure and manufacturing method and application thereof

Abstract

This invention discloses a bridge inductor structure, comprising a first metal wiring layer and a second metal wiring layer, with interlayer connecting posts and a dielectric layer between them. The interlayer connecting posts fill through-holes in the dielectric layer. The second metal wiring layer includes a plurality of second conductor segments arranged at intervals, and the first metal wiring layer includes a plurality of first conductor segments corresponding to the two ends of the second conductor segments. The second conductor segments and the first conductor segments are connected by interlayer connecting posts, and each second conductor segment is connected to the preceding second conductor segment through a first conductor segment at one end and to the following second conductor segment through a first conductor segment at the other end. The bridge inductor structure of this invention increases the Q value of the inductor. Filters using this bridge inductor structure can improve insertion loss characteristics and achieve better frequency band attenuation characteristics.

Description

Technical Field

[0001] This invention belongs to the technical field of semiconductors, specifically relating to a bridge inductor structure, its fabrication method, and its application. Background Technology

[0002] Inductors are an important component of various circuits in modern communication systems. In integrated circuits, passive devices such as inductors and capacitors are often integrated with active devices such as transistors on the same substrate to achieve specific functions. For example, 5G filter chips are based on gallium arsenide integrated passive device (IPD) technology, where inductors and capacitors are fabricated on a gallium arsenide substrate and combined to form an LC bandpass filter. The performance of inductors and other components will affect the performance and application of the filter.

[0003] Inductance Q-factor, also known as the quality factor of an inductor, is a key parameter for evaluating inductor devices. It refers to the ratio of the inductive reactance to the equivalent loss resistance of an inductor when operating under AC voltage at a specific frequency. A higher Q-factor indicates lower losses and higher efficiency. Currently, integrated inductors are typically manufactured using integrated circuit processes to form a spiral inductor coil on a substrate surface. However, the fabrication of the metal layer is difficult to control, limiting the Q-factor and hindering improvements in the insertion loss (IL) characteristics of the resulting filter. Therefore, developing new structures and processes to improve the Q-factor of inductors is of great significance. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a bridge inductor structure, its fabrication method, and its applications.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A bridge inductor structure is disposed on a substrate and includes a first metal wiring layer, a second metal wiring layer, interlayer connection pillars, and a dielectric layer. The dielectric layer covers the first metal wiring layer, the second metal wiring layer is disposed on the dielectric layer, and the interlayer connection pillars fill the through-holes penetrating the dielectric layer. The second metal wiring layer includes a plurality of second conductor segments arranged at intervals, and the first metal wiring layer includes a plurality of first conductor segments corresponding to the two ends of the second conductor segments. The second conductor segments and the first conductor segments are connected by interlayer connection pillars, and each second conductor segment is connected to the preceding second conductor segment through a first conductor segment at one end and to the following second conductor segment through a first conductor segment at the other end.

[0007] Optionally, the resistivity of the substrate is greater than or equal to 5 × 10⁻⁶. -4 Ω·cm.

[0008] Optionally, the thickness of the substrate is 80–150 μm.

[0009] Optionally, the first conductor segment is located between the ends of two adjacent second conductor segments on the same side, and is connected to the ends of the two adjacent second conductor segments respectively through the interlayer connecting post.

[0010] Optionally, the plurality of second conductor segments are arranged in parallel along a first direction, and the plurality of first conductor segments are alternately arranged on both sides of the second conductor segments, with each first conductor segment extending along the first direction.

[0011] Optionally, the second metal wiring layer further includes two lead-out sections disposed on the front and rear sides of the plurality of second conductor segments; the two last two second conductor segments at the front and rear positions each have a free end, and the two lead-out sections are connected to the two free ends in a one-to-one correspondence.

[0012] Optionally, the interlayer connecting column is a solid copper column.

[0013] Optionally, the material of the dielectric layer includes poly(p-phenylenebenzodioxazole) (PBO), benzocyclobutene (BCB), and polyimide (PI).

[0014] Optionally, the thickness of the first metal wiring layer is 3 to 8 μm, the height of the interlayer connecting post is 3 to 20 μm, and the thickness of the second metal wiring layer is 3 to 8 μm.

[0015] Optionally, the width of the second conductor segment is 10–15 μm.

[0016] A filter includes a substrate and a filtering circuit; the filtering circuit includes an inductor and a capacitor disposed on the substrate; wherein the inductor is a bridge inductor structure, including a first metal wiring layer, a second metal wiring layer, interlayer connecting pillars, and a dielectric layer disposed on the substrate, the dielectric layer covering the first metal wiring layer, the second metal wiring layer being disposed on the dielectric layer, and the interlayer connecting pillars penetrating the dielectric layer; the second metal wiring layer includes a plurality of second conductor segments arranged at intervals, and the first metal wiring layer includes a plurality of first conductor segments corresponding to the two ends of the second conductor segments; the second conductor segments and the first conductor segments are connected by interlayer connecting pillars, and each second conductor segment is connected to the preceding second conductor segment through a first conductor segment at one end, and to the following second conductor segment through a first conductor segment at the other end.

[0017] Optionally, the filter is a bandpass filter with a passband frequency range of 4.4 GHz to 5 GHz.

[0018] Optionally, the filter includes multiple resonators connected in parallel, with one end of each resonator capacitively coupled and the other end interconnected and connected in series with an inductor; the resonator is a parallel circuit of a capacitor and an inductor.

[0019] Optionally, the capacitor is a MIM capacitor, comprising a lower electrode, a dielectric layer, and an upper electrode, wherein at least one of the lower electrode and the upper electrode is located on the same layer as the metal wiring layer of the inductor, and can be fabricated using a co-channel metal deposition process.

[0020] An RF front-end module comprising the aforementioned filter.

[0021] A method for fabricating a bridge inductor structure includes the following steps:

[0022] (1) A first metal wiring layer is disposed on a substrate;

[0023] (2) A dielectric layer and interlayer connection posts are provided on the first metal wiring layer, wherein the interlayer connection posts penetrate the dielectric layer;

[0024] (3) A second metal wiring layer is formed on the dielectric layer, the second metal wiring layer comprising a plurality of second conductor segments arranged at intervals.

[0025] The first metal wiring layer includes a plurality of first conductor segments located at both ends of the second conductor segment; the second conductor segment and the first conductor segment are connected by interlayer connecting posts, and each second conductor segment is connected to the previous second conductor segment through the first conductor segment at one end and to the next second conductor segment through the first conductor segment at the other end.

[0026] Optionally, step (2) is formed by the following sub-steps:

[0027] Interlayer connection pillars are formed on the first metal wiring layer using an electroplating copper process;

[0028] A dielectric material is used to form a dielectric layer, which covers the exposed surface of the first metal wiring layer and the sides of the interlayer connection pillars.

[0029] Optionally, step (2) is formed by the following sub-steps:

[0030] A dielectric layer is formed on the first metal wiring layer, and the dielectric layer covers the surface of the first metal wiring layer;

[0031] A through-hole is formed in the dielectric layer;

[0032] The interlayer connecting pillars are formed in the through-holes using an electroplating process.

[0033] The beneficial effects of this invention are:

[0034] The bridge inductor structure of this invention is based on RDL (Re-distributed layer) technology. Through the design of a first metal wiring layer, a second metal wiring layer, and an interlayer interconnect structure, with the first metal wiring layer and the interlayer interconnect structure disposed within a dielectric layer, a thicker metal layer and a larger metal surface area can be easily obtained. This increases the charge stored per unit area of ​​the inductor's footprint, thereby significantly increasing the stored charge and improving the inductor's Q value. In some embodiments, filters employing this bridge inductor structure can achieve better insertion loss characteristics and more suitable frequency band attenuation characteristics. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of a bridge inductor structure according to one embodiment;

[0036] Figure 2 This is a schematic diagram of the connection structure between the first metal wiring layer, the second metal wiring layer, and the interlayer connection pillars.

[0037] Figure 3 for Figure 2 A top-down structural diagram showing the connections;

[0038] Figure 4 This is an exploded structural diagram of the first metal wiring layer, the second metal wiring layer, and the interlayer connection pillars;

[0039] Figure 5 A flowchart illustrating the manufacturing process of a bridge inductor structure according to one embodiment;

[0040] Figure 6 This is a process flow diagram of the fabrication of a bridge inductor structure according to another embodiment;

[0041] Figure 7 A schematic diagram of the circuit principle of a 5G filter as an example;

[0042] Figure 8 This is a schematic diagram of the circuit principle of the radio frequency front-end terminal module in the embodiment.

[0043] Figure 9 The inductance value L test spectrum is shown for the examples and comparative examples;

[0044] Figure 10 The Q-value test spectra are for the examples and comparative examples;

[0045] Figure 11 This is a schematic diagram of the insertion loss characteristic curves for the embodiments and comparative examples. Detailed Implementation

[0046] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments. The accompanying drawings are merely illustrative to facilitate understanding of the invention, and their specific proportions can be adjusted according to design requirements. The relative vertical and horizontal relationships of components, as well as the definitions of front and back sides in the graphics described herein, should be understood by those skilled in the art to refer to the relative positions of the components. Therefore, all can be flipped to present the same component, and all of this should fall within the scope disclosed in this specification.

[0047] refer to Figures 1 to 4 One embodiment of a bridge inductor structure is disposed on a substrate 1, including a first metal wiring layer 2, a second metal wiring layer 3, interlayer connecting pillars 4, and a dielectric layer 5. The first metal wiring layer 2 is disposed on the substrate 1, the dielectric layer 5 covers the first metal wiring layer 2, the second metal wiring layer 3 is disposed on the dielectric layer 5, and the interlayer connecting pillars 4 fill the through-holes penetrating the dielectric layer 5. The second metal wiring layer 3 includes a plurality of second conductor segments 31 arranged at intervals, and the first metal wiring layer 2 includes a plurality of first conductor segments 21 corresponding to the two ends of the second conductor segments 31. The second conductor segments 31 and the first conductor segments 21 are connected by the interlayer connecting pillars 4, and each second conductor segment 31 is connected to the previous second conductor segment 31 through the first conductor segment 21 at one end, and to the next second conductor segment 31 through the first conductor segment 21 at the other end, thereby forming a meandering inductor pattern.

[0048] In some specific embodiments, the substrate 1 has a resistivity ≥ 5 × 10⁻⁶. -4 The substrate material has a capacitance of Ω·cm, such as a silicon substrate, with a thickness of 80–150 μm, preferably 80–120 μm, for example 90 μm, 100 μm, 110 μm, or values ​​between these two. The resistivity is 0.001–10 (ohm-cm). The silicon substrate has a low K value and a low resistivity, and has a thinner thickness. Using a thin silicon substrate results in lower losses, which can increase the Q value of the inductor on the one hand, and reduce the overall thickness of the inductor chip on the other.

[0049] In this embodiment, the second conductor segments 31 are straight segments arranged parallel to each other along a first direction, and the straight segments extend along a second direction, with the first and second directions perpendicular to each other. A first conductor segment 21 is located between the ends of two adjacent second conductor segments 31 on the same side, extends along the first direction, and is perpendicularly connected to the ends of two adjacent second conductor segments 31 via interlayer connecting posts 4. Here, perpendicular connection means that the interlayer connecting posts 4 are configured to perpendicularly penetrate the dielectric layer 5. A plurality of first conductor segments 21 are alternately arranged on both sides of the second conductor segments 31 for alternating connections.

[0050] For ease of explanation, the two ends of the second conductor segment 31 are defined as end a and end b. The first conductor segment 21a located on the side of end a and the first conductor segment 21b located on the side of end b are alternately arranged in the first direction. Thus, the end a of each second conductor segment 31 is connected to the end a of the previous second conductor segment 31 to the same first conductor segment 21a, and the end b is connected to the end b of the next second conductor segment 31 to the same second conductor segment 31b, and so on. These parallel and spaced second conductor segments 31 located on the surface of the dielectric layer 5 are connected in series through the first conductor segments 21 located in the dielectric layer 5 and the interlayer connecting post 4. The two last two second conductor segments 31 each have a free end 31c. The second metal wiring layer 3 also includes two lead-out segments 32 respectively provided outside the two free ends 31c, and the two lead-out segments 32 are connected to the two free ends 31c one by one. The two lead-out segments 32 extend out of the edge of the dielectric layer 5 and are connected to the pad layer 6 provided on the outside, which facilitates external connection.

[0051] With the above settings, an inductance value similar to that of a spiral inductor can be obtained within a relatively small footprint.

[0052] In this embodiment, by controlling the thickness of the first metal wiring layer 2 and the second metal wiring layer 3, the amount of inductor charge stored can be increased, thereby improving the Q value of the inductor. Preferably, the thickness of the first metal wiring layer 2 is 1-8 μm, for example, 3-5 μm. When the thickness of the first metal wiring layer 2 is less than 1 μm, the resistance may increase, which is not conducive to improving the Q value of the inductor. The height of the interlayer connecting post 4 is 3-20 μm, for example, 3-10 μm. The thickness of the second metal wiring layer 3 is 3-10 μm. In some preferred embodiments, the thickness of the second metal wiring layer 3 is at least 5 μm. By effectively increasing the surface area of ​​the second conductor segment, the amount of stored charge can be effectively increased. When the thickness of the second metal wiring layer exceeds 10 μm, its effect on improving the Q value of the inductor becomes relatively weak.

[0053] In other embodiments, the second conductor segment 31 may also be a non-straight segment, such as a wavy, broken, arc segment or a combination thereof extending along the second direction.

[0054] In other embodiments, the second conductor segments may not be arranged in parallel; they may simply be spaced apart and not connected.

[0055] In other embodiments, the first direction and the second direction do not have to be perpendicular; they only need to have an angle between them.

[0056] The aforementioned bridge inductor structure is based on RDL (Re-distributed layer) technology. Through the design of a first metal wiring layer, a second metal wiring layer, and an interlayer vertical interconnect structure, and with the first metal wiring layer and the interlayer vertical interconnect structure set within the dielectric layer, and the second conductor segments arranged back and forth, it is easy to obtain a thicker metal thickness and a larger metal surface area. This increases the charge stored per unit area of ​​the inductor's footprint, thereby significantly increasing the stored charge and thus increasing the inductor's Q value.

[0057] As one possible implementation method, refer to Figure 5 The fabrication of the aforementioned bridge inductor structure includes the following steps:

[0058] 1) A first metal wiring layer 2 is formed on a substrate 1 using a copper process, wherein the line width of the first conductor segment is in the range of 15 to 20 μm and the thickness is 3 to 8 μm, for example 5 μm;

[0059] 2) Coat the first photoresist R1, and form several through holes V1 by exposure and development technology, with the bottom of the through holes V1 exposing the first metal wiring layer 2;

[0060] 3) A solid copper pillar connected to the metal wiring layer 2 is formed by filling the through-hole V1 with an electroplated copper process as an interlayer connection pillar 4;

[0061] The height of the interlayer connecting column ranges from 5 to 10 μm, and the diameter is approximately 10 μm.

[0062] 4) Remove the first photoresist;

[0063] 5) When PBO (poly(p-phenylenebenzodioxazole)) is used as a dielectric material to fill the area around the metal wiring layer 2 and the interlayer connection post 4 to form a dielectric layer 5, the PBO tightly covers the surface of the metal wiring layer 2 and the interlayer connection post 4, wherein the upper surface of the interlayer connection post 4 is exposed and flush with the upper surface of the dielectric layer 5.

[0064] 6) Coat the above surface with a second photoresist R2 and pattern it using exposure and development technology, wherein the surface of the interlayer connecting pillar 4 is exposed;

[0065] 7) A second metal wiring layer 3 is deposited using a copper process and connected to the interlayer connection pillar 4. The line width of the second conductor segment is 10-15 μm and the thickness is 5 μm. Then, the second photoresist R2 is stripped.

[0066] As another feasible implementation method, refer to Figure 6 The fabrication of the aforementioned bridge inductor structure includes the following steps:

[0067] 1) A first metal wiring layer 2 is formed on substrate 1 using a copper process, wherein the line width of the first conductor segment is in the range of 10-15 μm and the thickness is 5 μm;

[0068] 2) PBO (poly(p-phenylenebenzodioxazole)) is used as the dielectric material to form dielectric layer 5, which covers the surface of the first metal wiring layer 2.

[0069] 3) A plurality of vias V2 are formed in the dielectric layer 5, and the bottom of the vias V2 exposes the first metal wiring layer 2;

[0070] 4) A solid copper pillar connected to the metal wiring layer 2 is formed by filling the through-hole V2 with an electroplated copper process as an interlayer connection pillar 4;

[0071] The height of the interlayer connecting column ranges from 5 to 10 μm, and the diameter is approximately 10 μm; the upper surface of the interlayer connecting column 4 is flush with the upper surface of the dielectric layer 5.

[0072] 5) After patterning the photoresist, a second metal wiring layer 3 is deposited using a copper process and connected to the interlayer connection pillar 4. The line width of the second conductor segment is 5-10 μm and the thickness is 5 μm. Then the photoresist is stripped off.

[0073] The dielectric layer uses low dielectric constant materials such as PBO, which can reduce parasitic effects between metal interconnects and increase reliability. The inductor metal is produced using an electroplated copper process, which has good density and uniformity, allowing for well-filled solid copper pillars and high-quality top-to-bottom connections. It also facilitates obtaining a larger thickness, increasing the Q value of the inductor metal layer.

[0074] refer to Figure 7 and Figure 8 The bridge inductor structure of the present invention can be integrated into a 5G (BW = 4.4GHz ~ 5GHz) bandpass filter chip (5G Band Pass Filter - n77 / n79 BPF) and can be applied to radio frequency front-end terminal modules.

[0075] Specifically, the bandpass filter comprises multiple LC resonators arranged in parallel. One end of each LC resonator is capacitively coupled, and the other ends are interconnected and connected in series with an inductor. For example, refer to... Figure 7The two terminals of the bandpass filter (BPF) are connected in series via capacitors C9 and C4. The first resonator is formed by capacitor C1 and inductor L1 connected in parallel; the second resonator is formed by capacitor C3 and inductor L2 connected in parallel; and the third resonator is formed by capacitor C5 and inductor L3 connected in parallel. One end of the first resonator is connected between capacitor C9 and the terminal closest to capacitor C9; one end of the second resonator is connected between capacitor C9 and capacitor C4; and the third resonator is connected between capacitor C4 and the terminal closest to capacitor C4. The other ends of the three resonators are interconnected and connected in series with inductor L4 and grounded. The values ​​of the capacitors and inductors in the resonators are related to the passband communication frequency and bandwidth. Therefore, the passband frequency and bandwidth can be set by adjusting the values ​​of the capacitors and inductors in each resonator.

[0076] When the aforementioned bridge inductor structure is applied to an LC bandpass filter, it can be based on integrated circuit fabrication technology. The capacitor is a MIM capacitor, which includes a lower plate, a dielectric layer, and an upper plate. At least one of the lower plate and the upper plate is located on the same layer as the inductor's metal wiring layer. It can be fabricated using a co-channel metal deposition process, and the electrical connection and lead-out of the device structure can be achieved through interlayer metal interconnection and redistribution layer processes, thus achieving a simplified fabrication process and compatibility.

[0077] refer to Figure 8 Typically, an RF front-end module includes components such as a bandpass filter (BPF), power amplifier (PA), low-noise amplifier (LNA), transmit filter (Txinterstage SAW), receive filter (Rxinterstage SAW), and frequency converter. RF front-end modules have multiple signal transmission paths, including signal transmission and signal reception paths. Within each signal transmission path, by selecting a specific frequency band, it can process RF signals of a specific frequency band, such as N77 or N79.

[0078] Applying the aforementioned bridge inductor structure to a bandpass filter can improve the insertion loss characteristics of the 5G filter N79 and make the 5G filter N79 specifications easier to achieve.

[0079] refer to Figure 9 Using a conventional spiral inductor structure as a comparative example, both were designed to have similar inductance values. As can be seen from the figure, at a frequency of 5GHz, the inductance value L1 of the spiral inductor structure in the comparative example is 0.5159nH, and the inductance value L2 of the bridge inductor structure in the embodiment is 0.5155nH. The inductance values ​​produced by the two structures are very similar.

[0080] Based on this, the Q values ​​of the two are compared, and the results are as follows: Figure 10As shown, in the frequency band of 4.4 GHz to 5 GHz, the Q value of the spiral inductor structure in the comparative example is 19.674 to 20.405, while the Q value of the bridge inductor structure in the embodiment is 38.640 to 40.632, which is a significant improvement over the comparative example, with an improvement of about 90% to 110%.

[0081] Insertion loss characteristics were tested based on parameters S21 for the comparative examples and embodiments, such as... Figure 11 As shown, in 5GHz, the bridge inductor structure of this embodiment contributes to S21 = -0.387dB in the bandpass filter, while the comparative filter using a spiral inductor structure has S21 = -0.638dB. It can be seen that the inductor structure application of this embodiment reduces losses and improves the performance of the filter.

[0082] The above embodiments are only used to further illustrate a bridge inductor structure, its manufacturing method and application according to the present invention. However, the present invention is not limited to the embodiments. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A bridge inductor structure, characterized by: The inductance structure is arranged on a substrate, and includes a first metal wiring layer, a second metal wiring layer, an interlayer connecting column and a dielectric layer. The dielectric layer covers the first metal wiring layer, the second metal wiring layer is arranged on the dielectric layer, and the interlayer connecting column is filled in a through hole penetrating through the dielectric layer. The second metal wiring layer includes a plurality of second conductor segments arranged in parallel and spaced apart along a first direction. The first metal wiring layer includes a plurality of first conductor segments arranged alternately on both sides of the second conductor segments, and each first conductor segment extends along the first direction. The first conductor segments are located between the ends of two adjacent second conductor segments on the same side, and are connected with the ends of the two adjacent second conductor segments through the interlayer connecting column. Each second conductor segment is connected with a previous second conductor segment through a first conductor segment at one end, and is connected with a next second conductor segment through a first conductor segment at the other end.

2. The bridge inductor structure of claim 1, wherein: The substrate has a resistivity greater than or equal to 5 x 10 -4 Ω-cm.

3. The bridge inductor structure of claim 1, wherein: The thickness of the substrate is 80-150 μm.

4. The bridge inductor structure of claim 1, wherein: The second metal wiring layer further includes two lead-out segments arranged on both sides of the plurality of second conductor segments. The two last second conductor segments have free ends, and the two lead-out segments are connected with the two free ends one by one.

5. The bridge inductor structure of claim 1, wherein: The interlayer connecting column is a solid copper column.

6. The bridge inductor structure of claim 1, wherein: The material of the dielectric layer includes poly-p-phenylene benzobisoxazole (PBO), benzocyclobutene (BCB) and polyimide (PI).

7. The bridge inductor structure of claim 1, wherein: The thickness of the first metal wiring layer is 3-8 μm, the height of the interlayer connecting column is 3-20 μm, and the thickness of the second metal wiring layer is 3-8 μm.

8. The bridge inductor structure of claim 1, wherein: The width of the second conductor segment is 10-15 μm.

9. A filter characterized by: The filter includes a substrate and a filter circuit. The filter circuit includes an inductance and a capacitance arranged on the substrate. The inductance is a bridge type inductance structure, which includes a first metal wiring layer, a second metal wiring layer, an interlayer connecting column and a dielectric layer arranged on the substrate. The dielectric layer covers the first metal wiring layer, the second metal wiring layer is arranged on the dielectric layer, and the interlayer connecting column penetrates through the dielectric layer. The second metal wiring layer includes a plurality of second conductor segments arranged in parallel and spaced apart along a first direction. The first metal wiring layer includes a plurality of first conductor segments arranged alternately on both sides of the second conductor segments, and each first conductor segment extends along the first direction. The first conductor segments are located between the ends of two adjacent second conductor segments on the same side, and are connected with the ends of the two adjacent second conductor segments through the interlayer connecting column. Each second conductor segment is connected with a previous second conductor segment through a first conductor segment at one end, and is connected with a next second conductor segment through a first conductor segment at the other end.

10. The filter of claim 9, wherein: The filter is a band-pass filter, and the passband frequency range is 4.4 GHz-5 GHz.

11. The filter of claim 10, wherein: The filter includes a plurality of resonators arranged in parallel. One end of the resonators is coupled through a capacitance, the other end is connected with each other and in series with an inductance. The resonator is a parallel circuit of a capacitance and an inductance.

12. The filter of claim 9, wherein: The capacitance is a MIM capacitance, which includes a lower electrode plate, a dielectric layer and an upper electrode plate. At least one of the lower electrode plate and the upper electrode plate is located in the same layer as the metal wiring layer of the inductance.

13. A radio frequency front-end module, characterized in that: The filter includes the filter according to any one of claims 9-12.

14. A method of fabricating a bridge inductor structure, comprising: The filter includes the following steps: (1) arranging a first metal wiring layer on a substrate; (2) disposing a dielectric layer and an interlayer connection column on the first metal wiring layer, wherein the interlayer connection column penetrates the dielectric layer; (3) forming a second metal wiring layer on the dielectric layer, the second metal wiring layer comprising a plurality of second conductor segments arranged in parallel and spaced apart along a first direction; wherein the first metal wiring layer comprises a plurality of first conductor segments arranged alternately on both sides of the second conductor segments, and each first conductor segment extends along the first direction; the first conductor segment is located between the ends of the adjacent two second conductor segments on the same side, and is connected with the ends of the adjacent two second conductor segments through the interlayer connection column; each second conductor segment is connected with the previous second conductor segment through the first conductor segment at one end, and is connected with the next second conductor segment through the first conductor segment at the other end.

15. The method of claim 14, wherein: In the step (2), the following sub-steps are used to form: an interlayer connection column is formed on the first metal wiring layer by electroplating copper process; a dielectric layer is formed by filling dielectric material, and the dielectric layer covers the exposed surface of the first metal wiring layer and the side surface of the interlayer connection column.

16. The method of claim 14, wherein: In the step (2), the following sub-steps are used to form: a dielectric layer is formed on the first metal wiring layer, and the dielectric layer covers the surface of the first metal wiring layer; a through hole penetrating the dielectric layer is formed in the dielectric layer; the interlayer connection column is formed in the through hole by electroplating process.

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