Filter, radio frequency front-end module, and electronic device

Abstract

The present application provides a filter, a radio frequency front-end module, and an electronic device. The filter comprises: a series branch, the series branch comprising a first resonator, N+1 first capacitors, and a second resonator connected in series, wherein the N+1 first capacitors are arranged between the first resonator and the second resonator, the first resonator comprises a second capacitor and a first inductor connected in parallel, and the second resonator comprises a third capacitor and a second inductor connected in parallel, where N ≥ 1; and N parallel branches, each parallel branch comprising a third resonator, and the third resonator comprising a fourth capacitor and a third inductor connected in parallel, wherein one end of an i-th parallel branch among the N parallel branches is connected between an i-th first capacitor and an (i+1)-th first capacitor on the series branch, and the other end thereof is grounded, where 1 ≤ i ≤ N. The filter provided in the present application can reduce the number of inductors used, thereby reducing the size of the filter.

Description

Filter, radio frequency front-end module and electronic device

[0001] The present application claims priority to the Chinese patent application No. 202411280577.2, filed on September 12, 2024, entitled "Filter, radio frequency front-end module and electronic device", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the field of communication technology, in particular to a filter, a radio frequency front-end module and an electronic device. BACKGROUND

[0003] With the development of communication technology, the number of radio frequency channels increases from 4 to more than 45. In order to maintain a certain isolation degree between different channels to avoid channel crosstalk, a filter is added to each channel in the radio frequency front-end module, so the filter occupies a large proportion in the radio frequency front-end module. In order to promote the development of the radio frequency front-end module in the direction of high performance, miniaturization and high integration, the size of the filter should be reduced as much as possible. SUMMARY

[0004] The present application provides a filter, a radio frequency front-end module and an electronic device, which can reduce the size of the filter.

[0005] In a first aspect, a filter is provided, comprising: a series branch, the series branch comprising a first resonator, N+1 first capacitors and a second resonator connected in series, the N+1 first capacitors being arranged between the first resonator and the second resonator, the first resonator comprising a second capacitor and a first inductor connected in parallel, the second resonator comprising a third capacitor and a second inductor connected in parallel, N≥1; N parallel branches, each parallel branch of the N parallel branches comprising a third resonator, the third resonator comprising a fourth capacitor and a third inductor connected in parallel, one end of the i-th parallel branch of the N parallel branches being connected between the i-th first capacitor and the i+1-th first capacitor on the series branch, and the other end being grounded, 1≤i≤N.

[0006] The present application provides a filter, which reduces the number of inductors relative to existing filters of the same order, and can reduce the size of the filter without reducing the performance of the filter.

[0007] The first resonator, the second resonator, the third resonator, …, are all resonators, which can comprise a capacitor and an inductor connected in parallel. The M-order filter comprises M resonators, M≥3.

[0008] Exemplarily, one end of the first parallel branch of the N parallel branches is connected between the first first capacitor and the second first capacitor, and the other end is grounded; one end of the second parallel branch of the N parallel branches is connected between the second first capacitor and the third first capacitor, and the other end is grounded.

[0009] In some possible implementation manners, each parallel branch of the N parallel branches comprises a third resonator and a fifth capacitor connected in series, or each parallel branch of the N parallel branches comprises a third resonator and a fourth inductor connected in series.

[0010] With reference to the first aspect, in some implementation manners of the first aspect, at least part of the parallel branches comprises a fifth capacitor and / or a fourth inductor connected in series with the third resonator.

[0011] In some possible implementation manners, at least part of the parallel branches comprises a third resonator and a fifth capacitor connected in series, or at least part of the parallel branches comprises a third resonator and a fourth inductor connected in series, or at least part of the parallel branches comprises a third resonator, a fifth capacitor and a fourth inductor connected in series.

[0012] The application does not limit the connection sequence of the third resonator, the fifth capacitor and the fourth inductor. Exemplarily, each parallel branch can comprise a third resonator, a fifth capacitor and a fourth inductor connected in series, or each parallel branch can comprise a fifth capacitor, a third resonator and a fourth inductor connected in series, or each parallel branch can comprise a fifth capacitor, a fourth inductor and a third resonator connected in series.

[0013] The application provides a filter, each parallel branch comprising a third resonator, a fifth capacitor and a fourth inductor connected in series, which can improve the performance of the filter.

[0014] With reference to the first aspect, in some implementation manners of the first aspect, the fourth inductor is a parasitic inductance realized by a ground via.

[0015] The ground via is a metal wire used to realize ground connection, and the parasitic inductance refers to an inductance that is not intentionally designed in a circuit. Exemplarily, the fourth inductor is an inductance realized by a parasitic effect of a metal wire connected to ground.

[0016] The application provides a filter, and the fourth inductor on the parallel branch is a parasitic inductance realized by a ground via, which can improve the high-frequency harmonic suppression degree without increasing the layout area.

[0017] With reference to the first aspect, in some implementation manners of the first aspect, a quality factor of at least part of the first inductor, the second inductor and the third inductor is greater than a preset threshold.

[0018] The quality factor (Q value) of the inductor affects the steepness of the transition band of the filter and the energy loss. The higher the Q value of the inductor, the better the main indicators of the filter, such as frequency selectivity and insertion loss.

[0019] The application provides a filter, at least part of the inductor used in the resonator is a high-Q inductor, and the performance of the filter is improved.

[0020] In combination with the first aspect, in some implementations of the first aspect, at least part of the first inductor, the second inductor and the third inductor adopts a multi-metal layer structure, and the multi-metal layer structure includes a plurality of metal layers stacked together, and each two adjacent metal layers are connected by a via.

[0021] The metal layer and the via are made of a conductive metal such as copper (Cu), aluminum (Al), gold (Au) or silver (Ag).

[0022] The application provides a filter, and the inductor in at least part of the resonator adopts a multi-metal layer structure, so that the Q value of the inductor is improved, and the performance of the filter is improved.

[0023] In combination with the first aspect, in some implementations of the first aspect, the via and each metal layer are wrapped in an insulating protective layer, and the insulating protective layer is made of any one of polyimide, epoxy resin, polyethylene, polyimide resin or fluororesin.

[0024] It should be understood that different metal layers can be wrapped in the same material or different materials, and the application does not limit this.

[0025] The application provides a filter, and the via and each metal layer are wrapped in an insulating protective layer, so that the metal layer is protected, and the stress between the metal layers is reduced.

[0026] In combination with the first aspect, in some implementations of the first aspect, the thickness of each metal layer is 10 μm to 30 μm, and the height of the via is 5 μm to 30 μm.

[0027] Generally, the thicker the metal layer of the inductor, the higher the Q value of the inductor. The application provides a filter, and the inductor is designed by using a thick metal layer and a via, so that the Q value of the inductor is improved, and the performance of the filter is improved.

[0028] In combination with the first aspect, in some implementations of the first aspect, the multi-metal layer structure includes two metal layers or three metal layers.

[0029] The inductance in the resonator can include two metal layers or three metal layers. For example, the first inductance includes two metal layers, and the second inductance and the third inductance include three metal layers, or the first inductance and the second inductance include two metal layers, and the third inductance includes three metal layers.

[0030] The application provides a filter, which is designed by using a thick metal layer and a via, so that the Q value of the inductance is improved, and the performance of the filter is improved.

[0031] With reference to the first aspect, in some implementations of the first aspect, the multi-metal layer structure is arranged above a substrate and a bottom metal interconnection layer, the bottom metal interconnection layer is arranged above the substrate, and a metal layer close to the bottom metal interconnection layer in the multi-metal layer structure is connected to the bottom metal interconnection layer through a via.

[0032] The substrate can be made of glass, silicon (Si), SOI, gallium arsenide (GaAs), or the like. The bottom metal interconnection layer can be made of a conductive metal such as copper (Cu), aluminum (Al), gold (Au), silver (Ag), or the like.

[0033] The prior art usually directly arranges the inductance above the substrate. In the case that the metal layer of the inductance is thick, the stress between the metal layer and the substrate is too large, which causes delamination and affects the reliability of the filter. The application provides a filter, which adds a bottom metal interconnection layer on the substrate, effectively completes the interconnection between devices, and reduces the stress between the thick metal layer and the substrate and the reliability risk of the process.

[0034] With reference to the first aspect, in some implementations of the first aspect, the thickness of the bottom metal interconnection layer is 0.1 μm to 6 μm.

[0035] The application provides a filter, which adds a thin metal layer on the substrate, which serves as a bottom interconnection layer while reducing the stress between the thick metal layer and the substrate and the reliability risk of the process.

[0036] With reference to the first aspect, in some implementations of the first aspect, the bottom metal interconnection layer is wrapped in an insulating protective layer, and the insulating protective layer is made of any one of polyimide, epoxy resin, polyethylene, polyimide resin, and fluororesin.

[0037] The application provides a filter, in which the bottom metal interconnection layer is wrapped in an insulating protective layer, the insulating protective layer can serve as a stress buffer layer, the stress between the thick metal layer and the substrate is reduced, and the reliability risk of the process is reduced.

[0038] In a second aspect, the present application provides a radio frequency front-end module, comprising an amplifier, a radio frequency switch and the filter in any possible implementation manner of the first aspect.

[0039] The amplifier can be a power amplifier (PA) and / or a low noise amplifier (LNA).

[0040] In a third aspect, the present application provides an electronic device, comprising a circuit board and the radio frequency front-end module in the second aspect, wherein the radio frequency front-end module is arranged on the circuit board.

[0041] Exemplarily, the circuit board can be a printed circuit board (PCB).

[0042] The electronic device can further comprise a radio frequency chip, for example, a radio frequency integrated circuit (RFIC), wherein the RFIC is connected with the radio frequency front-end module and is arranged on the circuit board together with the radio frequency front-end module. BRIEF DESCRIPTION OF DRAWINGS

[0043] FIG. 1 is a schematic diagram of a frame of an electronic device according to an embodiment of the present application.

[0044] FIG. 2 is a schematic diagram of an application scenario of a filter according to an embodiment of the present application.

[0045] FIG. 3 is a schematic diagram of a structure of an inductor 300 according to an embodiment of the present application.

[0046] FIG. 4 is an exemplary flowchart of a preparation method of a high-Q inductor according to an embodiment of the present application.

[0047] FIG. 5 is a schematic diagram of a structure of an inductor 500 according to an embodiment of the present application.

[0048] FIG. 6 is an exemplary flowchart of another preparation method of a high-Q inductor according to an embodiment of the present application.

[0049] FIG. 7 is a circuit schematic diagram of a filter 700 according to an embodiment of the present application.

[0050] FIG. 8 is a circuit schematic diagram of a third-order filter 800 according to an embodiment of the present application.

[0051] FIG. 9 is a circuit schematic diagram of a fourth-order filter 900 according to an embodiment of the present application.

[0052] FIG. 10 is a circuit schematic diagram of a filter 1000 according to an embodiment of the present application.

[0053] FIG. 11 is a circuit schematic diagram of a third-order filter 1100 according to an embodiment of the present application.

[0054] FIG. 12 is a circuit schematic diagram of a fourth-order filter 1200 according to an embodiment of the present application.

[0055] FIG. 13 is a circuit schematic diagram of a third-order filter 1300 according to an embodiment of the present application.

[0056] FIG. 14 is a circuit schematic diagram of a third-order filter 1400 according to an embodiment of the present application.

[0057] FIG. 15 is a circuit schematic diagram of a third-order filter 1500 according to an embodiment of the present application.

[0058] FIG. 16 is a three-dimensional model schematic diagram of a fourth-order filter 900 according to an embodiment of the present application.

[0059] FIG. 17 is a packaging structure cross-sectional schematic diagram of a fourth-order filter 900 according to an embodiment of the present application.

[0060] FIG. 18 is an electromagnetic simulation result schematic diagram of a fourth-order filter 900 according to an embodiment of the present application. DETAILED DESCRIPTION

[0061] The technical solutions in the embodiments of the present application will be described below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work should fall within the protection scope of the present application.

[0062] In the embodiments of the present application, the words such as “example”, “for example”, and the like are used to represent an example, illustration, or description. Any embodiment or design scheme described as “example” in the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Rather, the word “example” is intended to present the concept in a specific manner.

[0063] The business scenarios described in the embodiments of the present application are used to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those of ordinary skill in the art can know that, as new business scenarios appear, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0064] Hereinafter, the terms "first", "second", etc. are used only for the purpose of description and do not imply or suggest relative importance or imply a specific number of the technical features indicated. Thus, the features defined with "first", "second" can explicitly or implicitly include one or more of the features.

[0065] In this specification, the phrase "one embodiment" or "some embodiments" etc. means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. Thus, the occurrences of the phrases "in one embodiment", "in some embodiments", "in other embodiments", "in additional embodiments", etc. in various places in the specification are not necessarily all referring to the same embodiment, but can mean "one or more but not all embodiments", unless otherwise specifically stated. The terms "comprising", "containing", "having" and their conjugates mean "including, but not limited to", unless otherwise specifically stated.

[0066] In this application, "at least one" means one or more, and "multiple" means two or more. The association relationship of the associated objects is described by "and / or", which means that there can be three relationships, for example, A and / or B, which can represent the cases of A alone, A and B together, and B alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects. "At least one of the following" or similar expressions means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, or c, can represent a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0067] To facilitate understanding of the embodiments of the present application, first, some definitions involved in the present application are briefly described.

[0068] 1. LC filter: refers to a filter circuit composed of inductance (L) and capacitance (C) combined design, which can remove or pass specific frequency passive devices. Capacitors have the characteristics of blocking direct current and passing alternating current, and the higher the alternating current frequency, the easier it is to pass. Inductance has the characteristics of blocking alternating current and passing direct current, and the higher the alternating current frequency, the less likely it is to pass. Therefore, capacitors and inductors are passive components with completely opposite characteristics. By combining capacitors and inductors, specific frequency signals can be removed or passed.

[0069] 2. Passive device: passive devices mainly include resistors, capacitors, inductors, converters, graders, matching networks, resonators, filters, mixers and switches, etc., which refer to electronic components that can display their characteristics without the need for an external power supply.

[0070] 3. Temperature drift: Short for temperature drift, it refers to the change in semiconductor device parameters caused by temperature variation.

[0071] 4. Lumped circuit: A circuit composed of many lumped elements, such as power sources, resistors, capacitors, inductors, etc.

[0072] 5. Bandpass: Refers to the frequency range that the filter allows to pass through.

[0073] 6. Stopband: Refers to the range of frequencies that the filter blocks from passing through.

[0074] 7. Transition band: Refers to the range between the bandpass and stopband.

[0075] 8. Insertion loss (IL): Refers to the power difference between the input and output signals after the signal passes through the filter. The smaller the insertion loss, the lower the attenuation of the input signal by the filter, and the better the performance of the filter.

[0076] 9. Return loss (RL): Return loss is a parameter that represents the signal reflection performance. Return loss represents the portion of the incident power that is reflected back to the signal source.

[0077] 10. BUMP: A metal bump that has been widely used since the advent of flip-chip technology. BUMP comes in various shapes, with the most common being spherical and cylindrical, as well as other shapes such as blocks. BUMP serves as an electrical interconnection between interfaces and a stress buffer.

[0078] 11. Multiplexer: A device with a single input port and multiple output ports, typically including duplexers, triplexers, and quadruplexers.

[0079] 12. Duplexer: Composed of two filters, one for transmission (Tx) and one for reception (Rx), sharing a common node (usually an antenna). Duplexer is mainly used in frequency division duplex radio applications. The design goal is to ensure that the transmission filter and the reception filter do not interfere with each other, and that the transmission signal in the reception output is significantly attenuated to avoid causing the reception front end to be overdriven.

[0080] 13. Silicon-on-insulator (SOI): Refers to a thin layer of single-crystal silicon covered on an insulator made of silicon dioxide or glass, hence the name "silicon-on-insulator". It can also be called a bonded wafer.

[0081] From the second generation mobile communication technology (2th-generation mobile communication technology, 2G) to the fifth generation mobile communication technology (5th-generation mobile communication technology, 5G), the number of radio frequency channels increases from 4 to more than 45. In order to maintain a certain isolation degree between different channels to avoid channel crosstalk, a filter is added to each channel in the radio frequency front-end module, so the filter occupies a large proportion in the radio frequency front-end module. In order to promote the development of the radio frequency front-end module to high performance, miniaturization and high integration, the filter should minimize the size while ensuring performance.

[0082] In the high frequency communication scenario of more than 3GHz, the lumped parameter filter such as low temperature co-fired ceramic (LTCC) filter and integrated passive device (IPD) filter has more stable temperature drift characteristics and larger bandwidth than acoustic filter. Compared with the LTCC filter using traditional printing process, the IPD filter uses advanced wafer manufacturing process, including thin film process and photolithography process, etc. to manufacture inductance and capacitance components including high conductivity metal on high resistivity wafer substrates such as glass, high resistance silicon, gallium arsenide, etc. Therefore, the IPD filter has the characteristics of high process precision, good consistency, high degree of low integration, etc. and may replace the LTCC filter to become the mainstream filter scheme of high frequency radio frequency front-end module in the future.

[0083] The quality factor (Q value) of the internal inductance component of the lumped parameter filter affects the transition band steepness and energy loss of the filter. The higher the Q value of the inductance, the better the main indicators such as frequency selectivity and insertion loss of the filter. The current mainstream IPD filter uses a planar spiral inductance with a thickness of 3μm-6μm, and its Q value is very small, which leads to poor radio frequency performance and seriously restricts the application of IPD filter.

[0084] Embodiments of the present application provide an electronic device. The electronic device is, for example, a consumer electronic product, a home electronic product, a vehicle-mounted electronic product, a financial terminal product, a communication electronic product. The consumer electronic product is, for example, a mobile phone, a pad, a notebook computer, an electronic reader, a personal computer (PC), a personal digital assistant (PDA), a desktop display, a smart wearable product (for example, a smart watch, a smart bracelet), a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a drone, and the like. The home electronic product is, for example, a smart door lock, a television, a remote controller, a refrigerator, a charging household small appliance (for example, a soybean milk machine, a sweeping robot), and the like. The vehicle-mounted electronic product is, for example, a vehicle-mounted navigation instrument, a vehicle-mounted high-density digital video disc (DVD), and the like. The financial terminal product is, for example, an automated teller machine (ATM) machine, a self-service terminal, and the like. The communication electronic product is, for example, a server, a memory, a radar, a base station, and the like.

[0085] For the sake of simplicity, the electronic device is taken as a mobile phone for example. As shown in FIG. 1, the electronic device 100 mainly includes a cover plate 11, a display screen 12, a middle frame 13, and a back shell 14. The back shell 14 and the display screen 12 are respectively located at two sides of the middle frame 13, and the middle frame 13 and the display screen 12 are arranged in the back shell 14. The cover plate 11 is arranged on a side of the display screen 12 away from the middle frame 13, and a display surface of the display screen 12 faces the cover plate 11.

[0086] The display screen 12 can be a liquid crystal display (LCD), in which case the liquid crystal display includes a liquid crystal display panel and a backlight module. The liquid crystal display panel is arranged between the cover plate 11 and the backlight module, and the backlight module is used to provide a light source for the liquid crystal display panel. The display screen 12 can also be an organic light emitting diode (OLED) display screen. Since the OLED display screen is a self-luminous display screen, it is not necessary to arrange the backlight module.

[0087] The middle frame 13 includes a bearing plate 131 and a frame 132 around the bearing plate 131. The electronic device 100 can further include a printed circuit board (PCB), a battery, a camera, and the like. The printed circuit board, the battery, the camera, and the like can be arranged on the bearing plate 131.

[0088] The electronic device 100 can further include a system on chip (SOC), a radio frequency chip, a radio frequency front-end module, etc. disposed on a PCB, the PCB being configured to carry and electrically connect the SOC, the radio frequency chip, the radio frequency front-end module, etc.

[0089] Embodiments of the present application provide a filter which can be applied in the electronic device 100 described above, for example, in the radio frequency front-end module in the electronic device 100. The filter provided by embodiments of the present application can be, for example, a low-pass filter, a high-pass filter, a band-pass filter, a band-stop filter, etc.

[0090] It should be understood that the filter provided by embodiments of the present application is not limited to being integrated in the electronic device 100. The filter can also be used as a separate component, or the filter can be integrated with a power amplifier and other components into a module, such as a radio frequency device, a radio frequency module, a filter module, etc. The filter is coupled to the power amplifier for signal processing and transmission.

[0091] FIG. 2 is a schematic diagram of an application scenario of a filter according to an embodiment of the present application.

[0092] The scenario is a data transmission and reception process of a communication system. The electronic device includes a transmission channel and a reception channel. The transmission channel includes a radio frequency integrated circuit (RFIC), a power amplifier (PA), a filter, a radio frequency switch, and an antenna. The reception channel includes an antenna, a radio frequency switch, a filter, a low noise amplifier (LNA), and an RFIC.

[0093] The transmission channel is responsible for converting digital signals into radio frequency signals for transmission. The reception channel is responsible for converting received radio frequency signals into digital signals, completing the data transmission and reception process.

[0094] In the data transmission process, first, the RFIC converts digital signals into radio frequency signals for use in wireless transmission. Then, the PA enhances the power of the radio frequency signals so that the signals can cover a longer distance during transmission. Next, the filter filters out unwanted frequency components to ensure that only signals of the target frequency pass through. Then, the radio frequency switch controls the state of the radio frequency signals to ensure that the radio frequency signals are transmitted to the antenna at the right time. Finally, the antenna converts the processed radio frequency signals into radio waves and radiates them, completing the signal transmission process.

[0095] During the receiving process of data, first, the antenna receives radio waves and converts them into radio frequency signals. Then, the radio frequency switch controls the flow direction of the received radio frequency signals, and transmits the radio frequency signals to the next stage of components for processing. Next, the filter filters out the frequency components that are not needed, and ensures that only the signals of the target frequency pass through. After that, the LNA amplifies the received radio frequency signals and reduces the noise in the radio frequency signals as much as possible to improve the signal quality. Finally, the RFIC converts the radio frequency signals processed in the foregoing into baseband signals for subsequent digital processing.

[0096] FIG. 3 is a structural schematic diagram of an inductor 300 provided by an embodiment of the present application.

[0097] The inductor 300 includes three metal layers M2, M3 and M4 arranged in layers, the M2 metal layer and the M3 metal layer are connected through a through hole (TV) 2, and the M3 metal layer and the M4 metal layer are connected through a TV 3. The inductor 300 is arranged above the substrate 30 and the M1 metal layer, the M1 metal layer is arranged above the substrate 30, and the M1 metal layer is used as a bottom metal interconnection layer. The M1 metal layer and the M2 metal layer are connected through a TV 1.

[0098] Optionally, the M1 metal layer and the TV 1 can be wrapped with an insulating protective layer 31, the insulating protective layer 31 can be used as a stress buffer layer, which can reduce the stress between the thick metal layer and the substrate 30, and reduce the reliability risk of the process.

[0099] Optionally, the M2 metal layer and the TV 2 can be wrapped with an insulating protective layer 32, the M3 metal layer and the TV 3 can be wrapped with an insulating protective layer 33, and the M4 metal layer can be wrapped with an insulating protective layer 34. The through hole and each metal layer are wrapped in the insulating protective layer, which can protect the metal layer and also reduce the stress between the metal layers.

[0100] The substrate 30 can be a wafer substrate 30, and the material of the wafer substrate 30 can be glass, silicon (Si), SOI, gallium arsenide (GaAs), etc.

[0101] The constituent materials of the M1 metal layer, the M2 metal layer, the M3 metal layer, the M4 metal layer, the TV 1, the TV 2 and the TV 3 can be conductive metals such as copper (Cu), aluminum (Al), gold (Au) and silver (Ag).

[0102] The constituent materials of the insulating protective layer 31, the insulating protective layer 32, the insulating protective layer 33 and the insulating protective layer 34 can be plastic packaging materials such as polyimide (PI), epoxy resin, polyethylene, polyimide resin and fluororesin.

[0103] The thickness of the M1 metal layer can be 0.1 μm to 6 μm. The embodiment of the present application adds a thin metal layer M1 on the substrate 30, which serves as a bottom metal interconnection layer and reduces the stress between the thick metal layer and the substrate 30, thereby reducing the reliability risk of the process.

[0104] The thickness of the M2 metal layer, the M3 metal layer, and the M4 metal layer can be 10 μm to 30 μm. The height of the TV1, the TV2, and the TV3, etc. can be 5 μm to 10 μm. Generally, the thicker the metal layer of the inductor, the higher the Q value of the inductor. The embodiment of the present application uses a thick metal layer with a via to design the inductor, which can improve the Q value of the inductor. It should be understood that the thickness parameter and the number of metal layers are only examples, and the inductor can also include more or fewer metal layers. When the number of layers of the inductor 300 is less than 3, the thickness of the metal layer can be increased accordingly. When the number of layers of the inductor 300 is greater than 3, the thickness of the metal layer can be reduced accordingly, and the height of the TV can also be adjusted accordingly.

[0105] One side or both sides of the substrate 30 can be prepared with a high-Q inductor, which can be a power amplifier, a low-noise amplifier, a radio frequency switch, a filter, a matching element, or other active or passive devices.

[0106] FIG. 4 is an exemplary flowchart of a method for preparing a high-Q inductor according to an embodiment of the present application. The high-Q inductor 300 shown in FIG. 3 can be obtained by the preparation method shown in FIG. 4.

[0107] 410, forming an M1 metal layer on the substrate 30.

[0108] The material of the substrate 30 can be glass, silicon (Si), SOI, gallium arsenide (GaAs), etc. The material of the M1 metal layer can be copper (Cu), aluminum (Al), gold (Au), silver (Ag), etc.

[0109] Exemplarily, a glass wafer is used as the substrate 30, and a layer of Al is sputtered on the glass wafer as the M1 metal layer by physical vapor deposition (PVD), electroplating, etc. After the M1 metal layer is patterned, it can serve as a bottom metal interconnection layer to connect inductors, capacitors, etc. The thickness of the M1 metal layer can be 0.1 μm to 6 μm.

[0110] Metal layer patterning includes local processing or pattern formation of the metal layer, so as to realize a patterned metal structure. In electronic manufacturing, metal layer patterning can refer to converting a designed metal layer wiring diagram, connection diagram, pad, etc. into an image or pattern required in actual manufacturing process, so as to produce a printed circuit board or an integrated circuit.

[0111] 420, coating and patterning an insulating protective layer 31 on the Ml metal layer.

[0112] The composition material of the insulating protective layer 31 can be plastic packaging material such as polyimide (PI), epoxy resin, polyethylene, polyimide resin, fluororesin, etc.

[0113] Exemplarily, a layer of PI is coated and patterned on the Ml metal layer to form the insulating protective layer 31. The insulating protective layer 31 can buffer the stress between the thick metal layer of the inductor 300 and the substrate 30 while protecting the Ml metal layer.

[0114] Then, a groove 1 is formed on the insulating protective layer 31 to accommodate the TVl. Exemplarily, the insulating protective layer 31 can be photo-etched to form the groove 1.

[0115] 430, forming an M2 metal layer and a TVl.

[0116] A layer of conductive metal is electroplated and patterned on the insulating protective layer 31 to form the M2 metal layer and the TVl. The thickness of the M2 metal layer can be 10-30 μm, and the height of the TVl can be 5-10 μm.

[0117] Exemplarily, a layer of copper is electroplated and patterned on the insulating protective layer 31 to form the M2 metal layer and the TVl, i.e., the composition material of the M2 metal layer and the TVl is copper. The M2 metal layer is part of the high-Q inductor 300, and the TVl is used to connect the high-Q inductor 300 and the bottom metal interconnection layer Ml.

[0118] 440, coating and patterning an insulating protective layer 32 on the M2 metal layer.

[0119] The composition material of the insulating protective layer 32 can be plastic packaging material such as PI, epoxy resin, polyethylene, polyimide resin, fluororesin, etc. Exemplarily, a layer of PI is coated and patterned on the M2 metal layer to form the insulating protective layer 32.

[0120] Then, a groove 2 is formed on the insulating protective layer 32 to accommodate the TV2. Exemplarily, the insulating protective layer 32 can be photo-etched to form the groove 2.

[0121] 450, forming an M3 metal layer and a TV2.

[0122] A layer of conductive metal is electroplated and patterned on the insulating protective layer 32 to form the M3 metal layer and the TV2. The thickness of the M3 metal layer can be 10-30 μm, and the height of the TV2 can be 5-10 μm.

[0123] Exemplarily, a layer of copper is plated and patterned on the insulating protective layer 32 to form the M3 metal layer and the TV2, i.e., the M3 metal layer and the TV2 are composed of copper. The M3 metal layer is part of the high-Q inductor 300, and the TV2 is used to connect the M2 metal layer and the M3 metal layer.

[0124] 460, the insulating protective layer 33 is coated and patterned on the M3 metal layer.

[0125] The insulating protective layer 33 can be composed of PI, epoxy resin, polyethylene, polyimide resin, fluororesin, or other plastic packaging materials. Exemplarily, a layer of PI is coated and patterned on the M3 metal layer to form the insulating protective layer 33.

[0126] Then, the groove 3 is formed on the insulating protective layer 33 to accommodate the TV3. Exemplarily, the insulating protective layer 33 can be subjected to photo-etching to form the groove 3.

[0127] 470, the M4 metal layer and the TV3 are formed.

[0128] A layer of conductive metal is plated and patterned on the insulating protective layer 33 to form the M4 metal layer and the TV3. The thickness of the M4 metal layer can be 10 μm-30 μm, and the height of the TV3 can be 5 μm-10 μm.

[0129] Exemplarily, a layer of copper is plated and patterned on the insulating protective layer 33 to form the M4 metal layer and the TV3, i.e., the M4 metal layer and the TV3 are composed of copper. The M4 metal layer is part of the high-Q inductor 300 and is used as a top metal interconnection layer to connect other inductors, capacitors, and pins. The TV3 is used to connect the M3 metal layer and the M4 metal layer.

[0130] 480, the insulating protective layer 34 is coated and patterned on the M4 metal layer.

[0131] The insulating protective layer 34 can be composed of PI, epoxy resin, polyethylene, polyimide resin, fluororesin, or other plastic packaging materials. Exemplarily, a layer of PI is coated and patterned on the M4 metal layer to form the insulating protective layer 34.

[0132] FIG. 5 is a structural schematic diagram of an inductor 500 provided by an embodiment of the present application.

[0133] The inductor 500 includes two metal layers M2 and M3 stacked and arranged, and the M2 metal layer and the M3 metal layer are connected through the TV2. The inductor 500 is arranged above the substrate 50 and the M1 metal layer, the M1 metal layer is arranged above the substrate 50, and the M1 metal layer is used as a bottom metal interconnection layer. The M1 metal layer and the M2 metal layer are connected through the TV1.

[0134] Optionally, the M1 metal layer and the TV1 can be wrapped with an insulating protective layer 51, which can serve as a stress buffer layer to reduce the stress between the thick metal layer and the substrate 50, thereby reducing the reliability risk of the process.

[0135] Optionally, the M2 metal layer and the TV2 can be wrapped with an insulating protective layer 52, and the M3 metal layer can be wrapped with an insulating protective layer 53. The through hole and each metal layer are wrapped in the insulating protective layer, which can protect the metal layer and reduce the stress between the metal layers.

[0136] The substrate 50 can be a wafer substrate 50, and the material of the wafer substrate 50 can be glass, silicon (Si), SOI, gallium arsenide (GaAs), etc.

[0137] The constituent material of the M1 metal layer, the M2 metal layer, the M3 metal layer, the TV1, and the TV2 can be a conductive metal such as copper (Cu), aluminum (Al), gold (Au), silver (Ag), etc.

[0138] The constituent material of the insulating protective layer 51, the insulating protective layer 52, and the insulating protective layer 53 can be a plastic packaging material such as PI, epoxy resin, polyethylene, polyimide resin, fluororesin, etc.

[0139] The thickness of the M1 metal layer can be 0.1 μm to 6 μm. The embodiment of the present application adds a thin metal layer M1 on the substrate 50, which serves as a bottom metal interconnection layer while reducing the stress between the thick metal layer and the substrate 50, thereby reducing the reliability risk of the process.

[0140] The thickness of the M2 metal layer and the M3 metal layer can be 10 μm to 30 μm. The height of the TV1 and the TV2 can be 5 μm to 10 μm.

[0141] One side or both sides of the substrate 50 can be prepared with a radio frequency device with high Q inductance, which can be an active or passive device such as a power amplifier, a low noise amplifier, a radio frequency switch, a filter, a matching element, etc.

[0142] FIG. 6 is an exemplary flowchart of another preparation method of a high Q inductance provided by the embodiment of the present application. The high Q inductance 500 shown in FIG. 5 can be obtained by the preparation method shown in FIG. 6.

[0143] 610, forming an M1 metal layer on the substrate 50.

[0144] The material of the substrate 50 can be glass, silicon (Si), SOI, gallium arsenide (GaAs), etc. The constituent material of the M1 metal layer can be a conductive metal such as copper (Cu), aluminum (Al), gold (Au), silver (Ag), etc.

[0145] Exemplarily, taking a glass wafer as the substrate 50, a layer of Al is sputtered on the glass wafer as the M1 metal layer by PVD, electroplating or the like. After patterning the M1 metal layer, the M1 metal layer can be used as a bottom interconnection layer to connect inductors, capacitors and the like. The thickness of the M1 metal layer can be 0.1 μm to 6 μm.

[0146] 620, coating and patterning an insulating protective layer 51 on the M1 metal layer.

[0147] The composition material of the insulating protective layer 51 can be PI, epoxy resin, polyethylene, polyimide resin, fluororesin or the like plastic packaging material.

[0148] Exemplarily, a layer of PI is coated and patterned on the M1 metal layer to form the insulating protective layer 51. The insulating protective layer 51 can buffer the stress between the thick metal layer of the inductor 500 and the substrate 50 while protecting the M1 metal layer.

[0149] Then, a groove 1 is formed on the insulating protective layer 51 to accommodate the TV1. Exemplarily, the insulating protective layer 51 can be subjected to photo-etching to form the groove 1.

[0150] 630, forming an M2 metal layer and a TV1.

[0151] A layer of conductive metal is electroplated and patterned on the insulating protective layer 51 to form the M2 metal layer and the TV1. The thickness of the M2 metal layer can be 10 μm to 30 μm, and the height of the TV1 can be 5 μm to 30 μm.

[0152] Exemplarily, a layer of copper is electroplated and patterned on the insulating protective layer 51 to form the M2 metal layer and the TV1, i.e. the composition material of the M2 metal layer and the TV1 is copper. The M2 metal layer is part of the high-Q inductor 500, and the TV1 is used to connect the high-Q inductor 500 and the bottom metal interconnection layer M1.

[0153] 640, coating and patterning an insulating protective layer 52 on the M2 metal layer.

[0154] The composition material of the insulating protective layer 52 can be PI, epoxy resin, polyethylene, polyimide resin, fluororesin or the like plastic packaging material. Exemplarily, a layer of PI is coated and patterned on the M2 metal layer to form the insulating protective layer 52.

[0155] Then, a groove 2 is formed on the insulating protective layer 52 to accommodate the TV2. Exemplarily, the insulating protective layer 52 can be subjected to photo-etching to form the groove 2.

[0156] 650, forming an M3 metal layer and a TV2.

[0157] A conductive metal layer is plated and patterned on the insulating protective layer 52 to form a M3 metal layer and a TV2. The thickness of the M3 metal layer can be 10-30 μm, and the height of the TV2 can be 5-30 μm.

[0158] For example, a copper layer is plated and patterned on the insulating protective layer 52 to form the M3 metal layer and the TV2, i.e., the M3 metal layer and the TV2 are made of copper. The M3 metal layer is part of the high-Q inductor 500 and is used as a top metal interconnection layer for connecting other inductors, capacitors and pins. The TV2 is used to connect the M3 metal layer and the M2 metal layer.

[0159] 660, an insulating protective layer 53 is coated and patterned on the M3 metal layer.

[0160] The insulating protective layer 53 can be made of PI, epoxy resin, polyethylene, polyimide resin, fluororesin or other plastic packaging materials. For example, a PI layer is coated and patterned on the M3 metal layer to form the insulating protective layer 53.

[0161] FIG. 7 is a circuit schematic diagram of a filter 700 according to an embodiment of the present application.

[0162] The filter 700 includes a series branch and N parallel branches. The series branch includes a first resonator, N+1 first capacitors C11-C1(N+1) and a second resonator in series. The first resonator includes a second capacitor C2 and a first inductor L1 in parallel, and the second resonator includes a third capacitor C3 and a second inductor L2 in parallel. N≥1.

[0163] Each of the N parallel branches includes a third resonator including a fourth capacitor C4 and a third inductor L3 in parallel. One end of an i-th parallel branch of the N parallel branches is connected between an i-th first capacitor and an i+1-th first capacitor of the series branch, and the other end is grounded, 1≤i≤N.

[0164] Optionally, at least part of the N parallel branches can further include a fifth capacitor C5 and / or a fourth inductor L4 in series with the third resonator. For example, each of the N parallel branches includes a fifth capacitor C5 and a fourth inductor L4 in series with the third resonator.

[0165] At least part of the first inductor L1, the second inductor L2 and the third inductor L3 can be the inductor 300 shown in FIG. 3 or the inductor 500 shown in FIG. 5. The inductor 300 and the inductor 500 are high-Q inductors, i.e., the Q value of the inductor 300 and the inductor 500 is greater than a preset threshold. The higher the Q value of the inductor, the better the main indicators of the filter, such as frequency selectivity and insertion loss.

[0166] The fourth inductor L4 can be a parasitic inductance realized by a ground via. The ground via is a metal wire used to realize a ground connection, and the parasitic inductance refers to an inductance that is not intentionally designed in a circuit. The parasitic inductance realized by the ground via can improve the high-frequency harmonic suppression degree without increasing the layout area.

[0167] FIG. 8 is a circuit schematic diagram of a third-order filter 800 provided by an embodiment of the present application.

[0168] The filter 800 includes a series branch and a parallel branch. The series branch includes a first resonator, a first capacitor C11, a first capacitor C12, and a second resonator in series, and the C11 and C12 are arranged between the first resonator and the second resonator. The first resonator includes a second capacitor C2 and a first inductor L1 in parallel, and the second resonator includes a third capacitor C3 and a second inductor L2 in parallel.

[0169] The parallel branch includes a third resonator, a fifth capacitor C5, and a fourth inductor L4 in series, and the third resonator includes a fourth capacitor C4 and a third inductor L3 in parallel. One end of the parallel branch is connected between the first capacitors C11 and C12, and the other end is grounded.

[0170] At least part of the inductors in the first inductor L1, the second inductor L2, and the third inductor L3 can adopt the inductor 300 shown in FIG. 3 or the inductor 500 shown in FIG. 5. The inductor 300 and the inductor 500 are high-Q inductors, that is, the Q value of the inductor 300 and the inductor 500 is greater than a preset threshold.

[0171] The fourth inductor L4 can be a parasitic inductance realized by a ground via. The ground via is a metal wire used to realize a ground connection, and the parasitic inductance refers to an inductance that is not intentionally designed in a circuit. The parasitic inductance realized by the ground via can improve the high-frequency harmonic suppression degree without increasing the layout area.

[0172] FIG. 9 is a circuit schematic diagram of a fourth-order filter 900 provided by an embodiment of the present application.

[0173] The filter 900 includes a series branch and two parallel branches. The series branch includes a first resonator, a first capacitor C11, a first capacitor C12, a first capacitor C13, and a second resonator in series, and the C11, C12, and C13 are arranged between the first resonator and the second resonator. The first resonator includes a second capacitor C2 and a first inductor L1 in parallel, and the second resonator includes a third capacitor C3 and a second inductor L2 in parallel.

[0174] Each of the two parallel branches includes a third resonator, a fifth capacitor C5 and a fourth inductor L4 in series, the third resonator including a fourth capacitor C4 and a third inductor L3 in parallel. One end of the first parallel branch is connected between the first capacitor C11 and C12, and the other end is grounded. One end of the second parallel branch is connected between the first capacitor C12 and C13, and the other end is grounded.

[0175] At least part of the inductance in the first inductor L1, the second inductor L2 and the third inductor L3 can be implemented by the inductor 300 shown in FIG. 3 or the inductor 500 shown in FIG. 5. The inductor 300 and the inductor 500 are high-Q inductors, i.e., the Q value of the inductor 300 and the inductor 500 is greater than a preset threshold.

[0176] The fourth inductor L4 can be a parasitic inductor implemented by a ground via. The ground via is a metal wire for implementing a ground connection, and the parasitic inductor refers to an inductor that is not intentionally designed in a circuit. The parasitic inductor implemented by the ground via can improve the high-frequency harmonic suppression degree without increasing the layout area.

[0177] FIG. 10 is a circuit schematic diagram of a filter 1000 provided by an embodiment of the present application.

[0178] The filter 1000 includes a series branch, a first parallel branch and a second parallel branch. The series branch includes N first resonators and N+1 first capacitors C11 to C1(N+1) in series, wherein the i-th first resonator is located between the i-th first capacitor and the i+1-th first capacitor, the first resonator includes a second capacitor C2 and a first inductor L1 in parallel, N≥1, 1≤i≤N.

[0179] The first parallel branch and the second parallel branch include a third resonator, and the third resonator includes a fourth capacitor C4 and a third inductor L3 in parallel. One end of the first parallel branch is connected between C11 and a first port, and the other end is grounded. One end of the second parallel branch is connected between C1(N+1) and a second port, and the other end is grounded. The first port is an input port of the filter and the second port is an output port of the filter, or the first port is an output port of the filter and the second port is an input port of the filter.

[0180] Optionally, at least part of the parallel branches in the first parallel branch and the second parallel branch can further include a fifth capacitor C5 and / or a fourth inductor L4 in series with the third resonator. For example, the first parallel branch and the second parallel branch both include a fifth capacitor C5 and a fourth inductor L4 in series with the third resonator.

[0181] At least part of the inductance in the first inductor L1 and the third inductor L3 can be implemented by the inductor 300 shown in FIG. 3 or the inductor 500 shown in FIG. 5. The inductor 300 and the inductor 500 are high-Q inductors, i.e., the Q value of the inductor 300 and the inductor 500 is greater than a preset threshold.

[0182] The fourth inductor L4 can be a parasitic inductance implemented by a ground via. The ground via is a metal wire used to implement a ground connection, and the parasitic inductance refers to an inductance that is not intentionally designed in a circuit. The parasitic inductance implemented by the ground via can improve the high-frequency harmonic suppression system without increasing the layout area.

[0183] FIG. 11 is a circuit schematic diagram of a third-order filter 1100 provided by an embodiment of the present application.

[0184] The filter 1100 includes a series branch and two parallel branches. The series branch includes a first capacitor C11, a first resonator, and a first capacitor C12 connected in series, and the C11 and C12 are arranged at two ends of the first resonator. The first resonator includes a second capacitor C2 and a first inductor L1 connected in parallel.

[0185] Each of the two parallel branches includes a third resonator, a fifth capacitor C5, and a fourth inductor L4 connected in series, and the third resonator includes a fourth capacitor C4 and a third inductor L3 connected in parallel. One end of the first parallel branch is connected between the C11 and a first port, and the other end is grounded. One end of the second parallel branch is connected between the C12 and a second port, and the other end is grounded. The first port is an input port of the filter and the second port is an output port of the filter, or the first port is an output port of the filter and the second port is an input port of the filter.

[0186] At least part of the inductance in the first inductor L1 and the third inductor L3 can be implemented by the inductor 300 shown in FIG. 3 or the inductor 500 shown in FIG. 5. The inductor 300 and the inductor 500 are high-Q inductors, i.e., the Q value of the inductor 300 and the inductor 500 is greater than a preset threshold.

[0187] The fourth inductor L4 can be a parasitic inductance implemented by a ground via. The ground via is a metal wire used to implement a ground connection, and the parasitic inductance refers to an inductance that is not intentionally designed in a circuit. The parasitic inductance implemented by the ground via can improve the high-frequency harmonic suppression system without increasing the layout area.

[0188] FIG. 12 is a circuit schematic diagram of a fourth-order filter 1200 provided by an embodiment of the present application.

[0189] The filter 1200 includes a series branch and two parallel branches. The series branch includes a first resonator, a second resonator, and first capacitors C11, C12, and C13 in series, the first resonator includes a second capacitor C2 and a first inductor L1 in parallel, and the second resonator includes a third capacitor C3 and a second inductor L2 in parallel. The first resonator is located between C11 and C12, and the second resonator is located between C12 and C13. The second resonator can be the same as or different from the first resonator.

[0190] Each of the two parallel branches includes a third resonator, a fifth capacitor C5, and a fourth inductor L4 in series, and the third resonator includes a fourth capacitor C4 and a third inductor L3 in parallel. One end of the first parallel branch is connected between C11 and a first port, and the other end is grounded. One end of the second parallel branch is connected between C13 and a second port, and the other end is grounded. The first port is an input port of the filter, and the second port is an output port of the filter, or the first port is an output port of the filter, and the second port is an input port of the filter.

[0191] At least part of the inductors in the first inductor L1, the second inductor L2, and the third inductor L3 can be implemented by the inductor 300 shown in FIG. 3 or the inductor 500 shown in FIG. 5. The inductor 300 and the inductor 500 are high-Q inductors, that is, the Q values of the inductor 300 and the inductor 500 are greater than a preset threshold.

[0192] The fourth inductor L4 can be a parasitic inductor implemented by a ground via. The ground via is a metal wire used to implement a ground connection, and the parasitic inductor refers to an inductor that is not intentionally designed in a circuit. The parasitic inductor implemented by the ground via can improve the high-frequency harmonic suppression degree without increasing the layout area.

[0193] FIG. 13 is a circuit schematic diagram of a third-order filter 1300 provided by an embodiment of the present application.

[0194] The filter 1300 includes a series branch and two parallel branches. The series branch includes a first resonator, a first capacitor C11, and a second capacitor C12 in series. The first resonator includes a second capacitor C2 and a first inductor L1 in parallel.

[0195] Each of the two parallel branches includes a third resonator, and the third resonator includes a fourth capacitor C4 and a third inductor L3 in parallel. One end of the first parallel branch is connected between the first capacitors C11 and C12, and the other end is grounded. One end of the second parallel branch is connected between the second capacitor C12 and a first port, and the other end is grounded. The first port is an input port or an output port of the filter.

[0196] Optionally, at least part of the two parallel branches can further include a fifth capacitor C5 and / or a fourth inductor L4 in series with the third resonator. For example, both of the two parallel branches include the fifth capacitor C5 and the fourth inductor L4 in series with the third resonator.

[0197] At least part of the first inductor L1 and the third inductor L3 can be implemented by the inductor 300 shown in FIG. 3 or the inductor 500 shown in FIG. 5. The inductor 300 and the inductor 500 are high-Q inductors, i.e., the Q value of the inductor 300 and the inductor 500 is greater than a preset threshold.

[0198] The fourth inductor L4 can be a parasitic inductor implemented by a ground via. The ground via is a metal wire used to implement a ground connection, and the parasitic inductor refers to an inductor that is not intentionally designed in a circuit. The parasitic inductor implemented by the ground via can improve the high-frequency harmonic suppression degree without increasing the layout area.

[0199] It should be understood that a person skilled in the art can also connect more first resonators in series or connect more third resonators in parallel on the basis of the third-order filter 1300 provided in the embodiments of the present application to form a new filter of three or more orders, which should also be covered in the protection scope of the present application.

[0200] FIG. 14 is a circuit schematic diagram of a third-order filter 1400 provided in an embodiment of the present application.

[0201] The filter 1400 includes a series branch and one parallel branch. The series branch includes a fourth resonator and a fifth resonator in series. The fourth resonator includes a capacitor C1 and an inductor L1 in series, and the fifth resonator includes a capacitor C2 and an inductor L2 in series. The parallel branch includes a sixth resonator including a capacitor C3 and an inductor L3 in parallel. One end of the parallel branch is connected between the capacitors C1 and C2, and the other end is grounded.

[0202] Optionally, the parallel branch can further include a capacitor C4 and / or an inductor L4 in series with the sixth resonator.

[0203] At least part of the inductors L1, L2 and L3 can be implemented by the inductor 300 shown in FIG. 3 or the inductor 500 shown in FIG. 5. The inductor 300 and the inductor 500 are high-Q inductors, i.e., the Q value of the inductor 300 and the inductor 500 is greater than a preset threshold.

[0204] The inductor L4 can be a parasitic inductor implemented by a ground via. The ground via is a metal wire used to implement a ground connection, and the parasitic inductor refers to an inductor that is not intentionally designed in a circuit. The parasitic inductor implemented by the ground via can improve the high-frequency harmonic suppression degree without increasing the layout area.

[0205] It should be understood that more resonators in series or in parallel can be added to the third-order filter 1400 provided by the embodiments of the present application to form a new filter of three or more orders, and the resonators can include a parallel capacitor and inductor or a series capacitor and inductor. The new filter of three or more orders should also be covered by the protection scope of the present application.

[0206] FIG. 15 is a circuit schematic diagram of a third-order filter 1500 provided by an embodiment of the present application.

[0207] The filter 1500 includes a series branch and a parallel branch. The series branch includes a seventh resonator, a capacitor C2 and an eighth resonator in series. The seventh resonator includes a capacitor C1 and an inductor L1 in series, and the eighth resonator includes a capacitor C3 and an inductor L2 in parallel. The parallel branch includes a ninth resonator including a capacitor C4 and an inductor L3 in parallel. One end of the parallel branch is connected between the capacitors C1 and C2, and the other end is grounded.

[0208] Optionally, the parallel branch can further include a capacitor C5 and / or an inductor L4 in series with the ninth resonator.

[0209] At least part of the inductors L1, L2 and L3 can be implemented by the inductor 300 shown in FIG. 3 or the inductor 500 shown in FIG. 5. The inductor 300 and the inductor 500 are high-Q inductors, i.e., the Q value of the inductor 300 and the inductor 500 is greater than a preset threshold.

[0210] The inductor L4 can be a parasitic inductor realized by a ground via. The ground via is a metal wire used to realize a ground connection, and the parasitic inductor refers to an inductor that is not intentionally designed in a circuit. The parasitic inductor realized by the ground via can improve the high-frequency harmonic suppression degree without increasing the layout area.

[0211] It should be understood that more resonators in series or in parallel can be added to the third-order filter 1500 provided by the embodiments of the present application to form a new filter of three or more orders, and the resonators can include a parallel capacitor and inductor or a series capacitor and inductor. The new filter of three or more orders should also be covered by the protection scope of the present application.

[0212] The first resonator to the ninth resonator in the above embodiments can be the same or different, the types of the plurality of inductors in the filter can be the same or different, and the types of the plurality of capacitors in the filter can be the same or different, which are not limited by the present application.

[0213] The structure and effect of the filter provided by the embodiments of the present application will be described in detail below by taking the filter 900 shown in FIG. 9 as an example.

[0214] Fig. 16 is a three-dimensional model diagram of a fourth-order filter 900 according to an embodiment of the present application. The underlined L3, C4, C5 and L4 belong to one parallel branch, and the non-underlined L3, C4, C5 and L4 belong to another parallel branch.

[0215] Fig. 17 is a cross-sectional view of a package structure of the fourth-order filter 900 according to an embodiment of the present application.

[0216] An inductor in the filter 900 includes metal layers M2, M3, M4 and vias TV2, TV3 connecting the metal layers, the M2 metal layer and the M3 metal layer are connected by the TV2, and the M3 metal layer and the M4 metal layer are connected by the TV3. The inductor is disposed above the substrate 30 and the M1 metal layer, the M1 metal layer is disposed above the substrate 30 and is used as a bottom metal interconnection layer. The M1 metal layer and the M2 metal layer are connected by the TV1.

[0217] The M1 metal layer, the M5 metal layer and a silicon nitride (SIN) layer constitute a capacitor. The M2 metal layer and the M5 metal layer are connected by the TV4.

[0218] The M4 metal layer has an under bump metallization (UBM) layer connected to a metal bump BUMP. The vias of the filter 900 and each metal layer are wrapped in an insulating protective layer, and the insulating protective layer can be composed of a plastic packaging material such as polyimide (PI), epoxy resin, polyethylene, polyimide resin, fluororesin, etc.

[0219] The substrate 30 can be composed of glass, silicon (Si), SOI, gallium arsenide (GaAs), etc. The M1 metal layer, the M2 metal layer, the M3 metal layer, the M4 metal layer, the M5 metal layer, the TV1, the TV2, the TV3 and the TV4 can be composed of a conductive metal such as copper (Cu), aluminum (Al), gold (Au), silver (Ag), etc.

[0220] The height of the substrate 30 is 100 μm, the height of the M1 metal layer is 1 μm, the height of the M2 metal layer is 15 μm, the height of the M3 metal layer is 15 μm, the height of the M4 metal layer is 15 μm, and the height of the M5 metal layer is 1 μm. The height of the TV1 is 4 μm, the height of the TV2 is 5 μm, the height of the TV3 is 5 μm, and the height of the TV4 is 2.8 μm. The height of the SIN layer is 0.2 μm, the height of the UBM layer is 5 μm, and the height of the BUMP is 40 μm. The package size of the filter model is only 1.0 mm x 0.5 mm (length x width), and the overall height of the filter is only about 205 μm including the 100 μm substrate and the 40 μm BUMP.

[0221] For example, L1 in filter 900 includes 2 layers of 15 μm thick copper and 1 layer of 25 μm high TV hole, L2 and L3 include 3 layers of 15 μm thick copper and 2 layers of 5 μm high TV hole. Table 1 shows the comparison of the Q value of the inductors provided by the embodiment of the present application and the conventional inductors actually tested at 5 GHz frequency point. As the inductance of the inductor is 3.00 nH, 1.50 nH and 0.75 nH respectively, it can be seen that the Q value of the inductor used in the filter of the embodiment of the present application is obviously improved compared with the conventional 5 μm thick copper inductor.

[0222] Table 1

[0223] Fig. 18 is a schematic diagram of the electromagnetic simulation result of a four-order filter 900 provided by the embodiment of the present application.

[0224] dB(S(18, 17)) represents the insertion loss from port 18 to port 17, dB(S(17, 17)) represents the return loss from port 17 to port 17, and dB(S(18, 18)) represents the return loss from port 18 to port 18. The passband range of filter 900 is 3.3 GHz-5.0 GHz, and the maximum insertion loss in the passband is 1.129 dB.

[0225] In vibration, a wave generated by a vibration is a sinusoidal wave with a certain frequency and the largest amplitude, which is called a fundamental wave. These small waves higher than the fundamental wave frequency are called harmonics. Harmonics refer to the components greater than the integer multiples of the fundamental wave frequency obtained by Fourier series decomposition of the periodic non-sinusoidal alternating current, which is usually referred to as high-order harmonics. When high-order harmonics are generated, due to the increase of frequency, the impedance of the capacitor instantaneously decreases, a large amount of current surges in, and thus the capacitor is overheated and even damaged, and resonance may occur, resulting in vibration and noise. As can be seen from the transmission zero point of Fig. 18, the filter of the embodiment of the present application also has more than 25 dB suppression in the low frequency band of 0.5 GHz-2.69 GHz and the high-order harmonic frequency band of 6.6 GHz-16 GHz.

[0226] Those skilled in the art should understand that various changes and substitutions can be made without departing from the true spirit and scope of the present application and equivalent solutions can be substituted. In addition, many modifications can be made to adapt the specific circumstances, materials, compositions of matter, processes, one or more process steps to the purpose, spirit and scope of the present application. All these modifications are intended to be within the scope of the appended claims of the present application.

[0227] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. It is to be understood that the above description is intended to be illustrative and not restrictive. The examples set forth herein are not intended to be exhaustive or to be unduly limit the scope of the application. Many modifications and variations to the examples described herein will be apparent to those skilled in the art from the foregoing description. Accordingly, the scope of the application should be determined from the appended claims and equivalents thereof.

[0228] The above description is only specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A filter, characterized by, The filter comprises: a series branch comprising a first resonator, N+1 first capacitors and a second resonator in series, the N+1 first capacitors being arranged between the first resonator and the second resonator, the first resonator comprising a second capacitor and a first inductor in parallel, the second resonator comprising a third capacitor and a second inductor in parallel, N≥1; N parallel branches, each of the N parallel branches comprising a third resonator comprising a fourth capacitor and a third inductor in parallel, one end of an i-th parallel branch of the N parallel branches being connected between an i-th first capacitor and an i+1-th first capacitor on the series branch, and the other end being grounded, 1≤i≤N.

2. The filter of claim 1, wherein, At least part of the N parallel branches comprises a fifth capacitor and / or a fourth inductor in series with the third resonator.

3. The filter of claim 2, wherein, The fourth inductor is a parasitic inductor realized by a via hole connected to the ground.

4. The filter according to any one of claims 1 to 3, characterized in that, A quality factor of at least part of the first inductor, the second inductor and the third inductor is greater than a preset threshold.

5. The filter according to any one of claims 1 to 4, characterized in that, At least part of the first inductor, the second inductor and the third inductor adopts a multi-metal layer structure, the multi-metal layer structure comprising a plurality of metal layers stacked, each adjacent two metal layers being connected by a via hole.

6. The filter of claim 5, wherein, The via hole and each metal layer are wrapped in an insulating protective layer, a composition material of the insulating protective layer comprising any one of polyimide, epoxy resin, polyethylene, polyimide resin, fluororesin.

7. The filter according to claim 5 or 6, characterized in that A thickness of each metal layer is 10μm-30μm, and a height of the via hole is 5μm-30μm.

8. The filter according to any one of claims 5 to 7, characterized in that, The multi-metal layer structure comprises two metal layers or three metal layers.

9. The filter according to any one of claims 5 to 8, characterized in that, The multi-metal layer structure is arranged above a substrate and a bottom metal interconnection layer, the bottom metal interconnection layer being above the substrate, a metal layer of the multi-metal layer structure close to the bottom metal interconnection layer being connected to the bottom metal interconnection layer by a via hole.

10. The filter of claim 9, wherein, A thickness of the bottom metal interconnection layer is 0.1μm-6μm.

11. The filter according to claim 9 or 10, characterized in that The bottom metal interconnection layer is wrapped in an insulating protective layer, a composition material of the insulating protective layer comprising any one of polyimide, epoxy resin, polyethylene, polyimide resin, fluororesin.

12. A radio frequency front end module, comprising: The filter comprises:

13. An electronic device, comprising: a series branch comprising a first resonator, N+1 first capacitors and a second resonator in series, the N+1 first capacitors being arranged between the first resonator and the second resonator, the first resonator comprising a second capacitor and a first inductor in parallel, the second resonator comprising a third capacitor and a second inductor in parallel, N≥1; N parallel branches, each of the N parallel branches comprising a third resonator comprising a fourth capacitor and a third inductor in parallel, one end of an i-th parallel branch of the N parallel branches being connected between an i-th first capacitor and an i+1-th first capacitor on the series branch, and the other end being grounded, 1≤i≤N. At least part of the N parallel branches comprises a fifth capacitor and / or a fourth inductor in series with the third resonator. The fourth inductor is a parasitic inductor realized by a via hole connected to the ground. A quality factor of at least part of the first inductor, the second inductor and the third inductor is greater than a preset threshold. At least part of the first inductor, the second inductor and the third inductor adopts a multi-metal layer structure, the multi-metal layer structure comprising a plurality of metal layers stacked, each adjacent two metal layers being connected by a via hole. The via hole and each metal layer are wrapped in an insulating protective layer, a composition material of the insulating protective layer comprising any one of polyimide, epoxy resin, polyethylene, polyimide resin, fluororesin. A thickness of each metal layer is 10μm-30μm, and a height of the via hole is 5μm-30μm. The multi-metal layer structure comprises two metal layers or three metal layers. The multi-metal layer structure is arranged above a substrate and a bottom metal interconnection layer, the bottom metal interconnection layer being above the substrate, a metal layer of the multi-metal layer structure close to the bottom metal interconnection layer being connected to the bottom metal interconnection layer by a via hole. A thickness of the bottom metal interconnection layer is 0.1μm-6μm. The bottom metal interconnection layer is wrapped in an insulating protective layer, a composition material of the insulating protective layer comprising any one of polyimide, epoxy resin, polyethylene, polyimide resin, fluororesin. The filter comprises: a series branch comprising a first resonator, N+1 first capacitors and a second resonator in series, the N+1 first capacitors being arranged between the first resonator and the second resonator, the first resonator comprising a second capacitor and a first inductor in parallel, the second resonator comprising a third capacitor and a second inductor in parallel, N≥1; N parallel branches, each of the N parallel branches comprising a third resonator comprising a fourth capacitor and a third inductor in parallel, one end of an i-th parallel branch of the N parallel branches being connected between an i-th first capacitor and an i+1-th first capacitor on the series branch, and the other end being grounded, 1≤i≤N. At least part of the N parallel branches comprises a fifth capacitor and / or a fourth inductor in series with the third resonator. The fourth inductor is a parasitic inductor realized by a via hole connected to the ground. A quality factor of at least part of the first inductor, the second inductor and the third inductor is greater than a preset threshold. At least part of the first inductor, the second inductor and the third inductor adopts a multi-metal layer structure, the multi-metal layer structure comprising a plurality of metal layers stacked, each adjacent two metal layers being connected by a via hole. The via hole and each metal layer are wrapped in an insulating protective layer, a composition material of the insulating protective layer comprising any one of polyimide, epoxy resin, polyethylene, polyimide resin, fluororesin. A thickness of each metal layer is 10μm-30μm, and a height of the via hole is 5μm-30μm. The multi-metal layer structure comprises two metal layers or three metal layers. The multi-metal layer structure is arranged above a substrate and a bottom metal interconnection layer, the bottom metal interconnection layer being above the substrate, a metal layer of the multi-metal layer structure close to the bottom metal interconnection layer being connected to the bottom metal interconnection layer by a via hole. A thickness of the bottom metal interconnection layer is 0.1μm-6μm. The bottom metal interconnection layer is wrapped in an insulating protective layer, a composition material of the insulating protective layer comprising any one of polyimide, epoxy resin, polyethylene, polyimide resin, fluororesin.

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