阅读说明：本技术 单片集成功率放大器和体声波滤波器的芯片结构及制备方法 (Chip structure of monolithic integrated power amplifier and bulk acoustic wave filter and preparation method thereof ) 是由 孙成亮 刘炎 蔡耀 徐沁文 邹杨 于 2019-10-18 设计创作，主要内容包括：本发明公开了一种单片集成功率放大器和体声波滤波器的芯片结构及制备方法,该结构中：功率放大器设置在硅衬底的上表面；体声波滤波器设置在硅衬底的下表面,包括串联谐振器、并联谐振器；通过硅通孔技术将体声波滤波器的电极引出至硅衬底的上表面,实现功率放大器与体声波滤波器的电气互联；封装盖帽分别设置在硅衬底的上下两面,通过共晶键合技术对两个封装盖帽分别进行封装,在硅衬底的上下两面均形成空腔,上表面的空腔中容纳功率放大器,下表面的空腔中容纳体声波滤波器,实现器件的集成封装。本发明提出的结构有效的节省了射频前端的面积和体积,减少了射频前端制作的成本,有助于射频系统的高度集成化和模块化。(The invention discloses a chip structure of a monolithic integrated power amplifier and a bulk acoustic wave filter and a preparation method thereof, wherein the chip structure comprises the following components: the power amplifier is arranged on the upper surface of the silicon substrate; the bulk acoustic wave filter is arranged on the lower surface of the silicon substrate and comprises a series resonator and a parallel resonator; leading out an electrode of the bulk acoustic wave filter to the upper surface of the silicon substrate through a through silicon via technology, and realizing the electrical interconnection of the power amplifier and the bulk acoustic wave filter; the packaging caps are respectively arranged on the upper surface and the lower surface of the silicon substrate, the two packaging caps are respectively packaged through a eutectic bonding technology, cavities are formed in the upper surface and the lower surface of the silicon substrate, the cavity in the upper surface accommodates the power amplifier, and the cavity in the lower surface accommodates the bulk acoustic wave filter, so that integrated packaging of the device is realized. The structure provided by the invention effectively saves the area and the volume of the radio frequency front end, reduces the manufacturing cost of the radio frequency front end, and is beneficial to high integration and modularization of a radio frequency system.)

1. A chip architecture for monolithically integrating a power amplifier and a bulk acoustic wave filter, comprising: a silicon substrate (106), a power amplifier (101), a bulk acoustic wave filter and a packaging cover cap; wherein:

the power amplifier (101) is arranged on the upper surface of the silicon substrate (106); the bulk acoustic wave filter is arranged on the lower surface of the silicon substrate (106) and comprises a series resonator (211) and a parallel resonator (212); the electrode of the bulk acoustic wave filter is led out to the upper surface of a silicon substrate (106) through a through silicon via technology, so that the power amplifier (101) and the bulk acoustic wave filter are electrically interconnected;

the packaging caps are respectively arranged on the upper surface and the lower surface of the silicon substrate (106), the two packaging caps are respectively packaged through the eutectic bonding technology, cavities are formed in the upper surface and the lower surface of the silicon substrate (106), the power amplifier (101) is contained in the cavity on the upper surface, the bulk acoustic wave filter is contained in the cavity on the lower surface, and integrated packaging of the device is achieved.

2. The chip structure of monolithically integrated power amplifier and bulk acoustic wave filter of claim 1, wherein the power amplifier (101) is fabricated on the upper surface of the silicon substrate (106), a through hole is etched on the silicon substrate (106) by a through silicon via technique to lead out the bulk acoustic wave filter electrode to the upper surface of the silicon substrate (106), the RF interface (102) and the circuit interface (103) are led out from the upper surface of the silicon substrate (106), the input interface (104) and the output interface (105) of the external RF signal, and the filter electrode interface (207); the electrical interconnection of the bulk acoustic wave filter with an RF interface (102) and a circuit interface (103) of a power amplifier (101) and an input interface (104) and an output interface (105) of an external radio frequency signal is realized.

3. The chip structure of a monolithically integrated power amplifier and bulk acoustic wave filter according to claim 1, characterized in that the power amplifier (101) comprises a high power transistor, a bias voltage circuit, an input matching circuit and an output matching circuit.

4. The chip structure of the monolithically integrated power amplifier and bulk acoustic wave filter according to claim 1, wherein the package cap comprises an upper silicon wafer (301) disposed on an upper surface of the silicon substrate (106) and a lower silicon wafer (302) disposed on a lower surface of the silicon substrate, cavities are disposed in the upper silicon wafer (301) and the lower silicon wafer (302), two groups of silicon wafers with cavities are packaged with the device by eutectic bonding technology to form the package cap, the power amplifier (101) is accommodated in the cavity of the upper silicon wafer (301), and the bulk acoustic wave filter is accommodated in the cavity of the lower silicon wafer (302).

5. The chip structure of claim 4, wherein the package cap is implemented by two packages, the first package occurs after the process of the power amplifier (101) on the upper surface is completed, and the second package occurs after the process of the bulk acoustic wave filter on the lower surface is completed.

6. The chip structure of the monolithically integrated power amplifier and bulk acoustic wave filter of claim 1, wherein the series resonator (211) and the shunt resonator (212) are fabricated on a lower surface of the silicon substrate (106), the silicon substrate (106) is thinned by etching a cavity on the lower surface of the silicon substrate (106), the sacrificial layer (201) is filled, and the sacrificial layer (201) is parallel to the lower surface of the silicon substrate (106) by using a chemical mechanical polishing technique; depositing/patterning a bottom electrode (202), a piezoelectric film (203), a top electrode (204) and a mass loading layer (205) on the sacrificial layer (201) in sequence to form a series resonator (211) and a parallel resonator (212); the bottom electrodes of the series resonator (211) and the parallel resonator (212) are isolated from each other, and the top electrodes are communicated with each other.

7. The chip structure of a monolithically integrated power amplifier and bulk acoustic wave filter according to claim 6, characterized in that the series resonator (211) and the shunt resonator (212) are provided with release holes (206), through which release holes (206) an etchant is introduced for etching away the sacrificial layer (201) and releasing the sacrificial layer (201), forming an air cavity (208) between the silicon substrate (106) and the bottom electrode (202).

8. The chip structure of monolithically integrated power amplifier and bulk acoustic wave filter according to claim 2, characterized in that through-silicon-via technology is used to etch a via (107) on a silicon substrate (106), through the via (107) is used to lead out an electrode of the bulk acoustic wave filter to an electrode interface (207) on the upper surface of the silicon substrate (106), and to realize electrical interconnection of the electrode of the bulk acoustic wave filter with the RF interface (102) of the functional amplifier (101), the circuit interface (103), and the input (104) and the output interface (105) of external radio frequency signals.

9. A method for preparing a chip structure of a monolithic integrated power amplifier and a bulk acoustic wave filter is characterized by comprising the following steps:

the method comprises the following steps: manufacturing a power amplifier on a silicon substrate, and leading out an RF interface and a circuit interface;

wherein, this power amplifier includes: the circuit comprises a high-power transistor, a bias voltage circuit, an input matching circuit and an output matching circuit;

step two: packaging an upper silicon wafer on a substrate by using a eutectic bonding technology to form an upper packaging cover cap, and accommodating a power amplifier in a cavity;

step three: thinning the silicon substrate, etching a cavity at the bottom of the silicon substrate, filling a sacrificial layer, using a chemical mechanical polishing technology to realize that the sacrificial layer is parallel to the surface of the silicon substrate, and depositing/patterning a bottom electrode, a piezoelectric film, a top electrode and a mass load layer in turn to form a series resonator and a parallel resonator; the bottom electrodes of the series resonators and the parallel resonators are isolated from each other, and the top electrodes are communicated with each other;

step four: introducing an etchant through the release hole, etching off the sacrificial layer, and forming an air cavity between the substrate and the bottom electrode;

step five: etching a through hole on a silicon substrate by a through silicon via technology to lead out a filter electrode to the upper surface of the substrate, and realizing electrical interconnection with an RF interface of a power amplifier, a circuit interface and an input/output interface of an external radio frequency signal;

step six: and packaging the lower silicon wafer at the bottom of the silicon substrate by using a eutectic bonding technology to form a lower packaging cap, wherein the cavity contains the nano-filter.

Technical Field

The invention relates to the field of wireless communication, in particular to a chip structure of a monolithic integrated power amplifier and a bulk acoustic wave filter and a preparation method thereof.

Background

The wireless communication module of the terminal device is mainly divided into four parts, namely an antenna, a radio frequency front end module (RF FEM), a radio frequency transceiver module and a baseband signal processor. The radio frequency front end is the core of wireless connection and is a basic part for realizing signal transmission and reception between the antenna and the radio frequency transceiving module.

An existing radio frequency system is shown in fig. 1 and includes a baseband chip, a transceiver, a Power Amplifier (PA), a filter, a duplexer, a radio frequency switch, a Low Noise Amplifier (LNA), an antenna, and the like. The baseband chip is used for coding and decoding mobile communication signals; the transceiver is used for frequency conversion and channel selection of radio frequency signals; the power amplifier is responsible for amplifying the radio frequency signal of the transmitting channel; the filter is responsible for filtering the transmitting and receiving signals; the duplexer is responsible for duplex switching of the FDD system and radio frequency signal filtering of a receiving/sending channel; the radio frequency switch is responsible for switching between receiving and transmitting channels; the low noise amplifier is mainly used for amplifying small signals in a receiving channel; the antenna is used for transmitting and receiving electromagnetic waves.

When the radio frequency system is in a transmitting state, a receiving branch of a switch is closed, a transmitting branch is opened, a low-noise amplifier is in a closed state, a signal sent from a transceiver is amplified through a Power Amplifier (PA), noise waves are filtered through a filter, the signal is connected to the transmitting branch of the switch after passing through a duplexer, and the signal is transmitted through an antenna; when the radio frequency part is in a receiving state, a receiving branch of the switch opens a transmitting channel and closes, the power amplifier is closed, the low-noise amplifier amplifies the signal, and the amplified signal is transmitted to the transceiver for signal processing to complete signal receiving.

Power amplifiers are key modules of radio frequency systems and require the low power signal of a transmitter to be amplified sufficiently to meet the requirements of the communication protocol. The PA directly determines the distance, signal quality, and even standby time of the wireless communication of the mobile phone, and is an important part of the radio frequency system. The general structure of the power amplifier is shown in fig. 2, and mainly includes a transistor, a bias voltage circuit, and an input/output matching circuit.

The transistor is the core of the power amplifier with amplification capability. The essence of the power amplifier is that the power amplifier works as a controlled current source in a classical power amplifier or an equivalent switch in a switch type power amplifier, and the task of the power amplifier is to convert the power of a direct current power supply without information into radio frequency output power required by people; the bias is an indispensable condition for the transistor to work, different biases are set for the transistor, the static working points of the transistor are different, and different working modes appear; the input and output matching circuit is mainly used for changing the performance and the working type of the power amplifier.

Band pass filters currently used in radio frequency systems are mainly dielectric ceramic filters and Surface Acoustic Wave (SAW) filters. The dielectric ceramic filter has the problems of large volume, poor process compatibility and the like, so that the further development of the dielectric ceramic filter is limited. Although the SAW filter can achieve a higher Q value and a smaller geometric size, the difficulty of the photolithography process is increased and the high-frequency application is limited because the finger width and the gap of the interdigital electrode are inversely proportional to the working frequency. Film Bulk Acoustic Resonators (FBARs) are a completely new class of radio frequency filters. The FBAR device is much smaller than a traditional electromagnetic wave-based dielectric filter in size, has higher working frequency, and has better out-of-band rejection performance and lower insertion loss. Compared with the SAW filter, the bulk acoustic wave filter has certain advantages in the aspects of power capacity, filtering performance, frequency temperature coefficient and the like, and the manufacturing process of the bulk acoustic wave filter is compatible with the semiconductor process, so that the Bulk Acoustic Wave (BAW) filter is the best choice in high-frequency application above gigahertz.

With the rapid development of LTE, the integration of the radio frequency front end is an inevitable trend due to the continuous increase of commercial frequency bands. Integration can reduce cost, improve performance, and provide turn-key solutions to system integrators. The radio frequency front end integration has two development directions of single chip integration and hybrid integration. At present, the method is easier to realize through a form of hybrid integration (SiP packaging), and is also the direction of the gravity of various manufacturers.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a chip structure of a monolithic integrated power amplifier and a bulk acoustic wave filter and a method for manufacturing the same, aiming at the defects in the prior art.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the invention provides a chip structure of a monolithic integrated power amplifier and a bulk acoustic wave filter, which comprises: the device comprises a silicon substrate, a power amplifier, a bulk acoustic wave filter and a packaging cover cap; wherein:

the power amplifier is arranged on the upper surface of the silicon substrate; the bulk acoustic wave filter is arranged on the lower surface of the silicon substrate and comprises a series resonator and a parallel resonator; leading out an electrode of the bulk acoustic wave filter to the upper surface of the silicon substrate through a through silicon via technology, and realizing the electrical interconnection of the power amplifier and the bulk acoustic wave filter;

the packaging caps are respectively arranged on the upper surface and the lower surface of the silicon substrate, the two packaging caps are respectively packaged through a eutectic bonding technology, cavities are formed in the upper surface and the lower surface of the silicon substrate, the cavity in the upper surface accommodates the power amplifier, and the cavity in the lower surface accommodates the bulk acoustic wave filter, so that integrated packaging of the device is realized.

Furthermore, the power amplifier is manufactured on the upper surface of a silicon substrate, a through hole is etched on the silicon substrate through a silicon perforation technology to lead out a bulk acoustic wave filter electrode to the upper surface of the silicon substrate, an RF interface and a circuit interface, an input interface and an output interface of an external radio frequency signal and a filter electrode interface are led out from the upper surface of the silicon substrate; and the electrical interconnection of the RF interface and the circuit interface of the bulk acoustic wave filter and the power amplifier, and the input interface and the output interface of the external radio frequency signal is realized.

Further, the power amplifier of the present invention includes a high power transistor, a bias voltage circuit, an input matching circuit, and an output matching circuit.

Further, the packaging cap comprises an upper silicon wafer and a lower silicon wafer, wherein the upper silicon wafer and the lower silicon wafer are arranged on the upper surface of the silicon substrate, cavities are formed in the upper silicon wafer and the lower silicon wafer, two groups of silicon wafers with the cavities are packaged with the device through a eutectic bonding technology to form the packaging cap, the power amplifier is contained in the cavity of the upper silicon wafer, and the bulk acoustic wave filter is contained in the cavity of the lower silicon wafer.

Furthermore, the packaging cap is realized by packaging twice, the first packaging is carried out after the manufacturing process of the power amplifier on the upper surface is finished, and the second packaging is carried out after the manufacturing process of the bulk acoustic wave filter on the lower surface is finished.

Furthermore, the resonators are connected in series and in parallel in the process of manufacturing the lower surface of the silicon substrate, the cavity is etched on the lower surface of the silicon substrate, the silicon substrate is thinned, the sacrificial layer is filled, and the sacrificial layer is parallel to the lower surface of the silicon substrate by using a chemical mechanical polishing technology; depositing/patterning a bottom electrode, a piezoelectric film, a top electrode and a mass load layer on the sacrificial layer in sequence to form a series resonator and a parallel resonator; the bottom electrodes of the series resonators and the parallel resonators are isolated from each other, and the top electrodes are communicated with each other.

Further, the series resonator and the parallel resonator of the present invention are provided with release holes through which an etchant is introduced for etching away the sacrificial layer and releasing the sacrificial layer to form an air cavity between the silicon substrate and the bottom electrode.

Furthermore, the through hole is etched on the silicon substrate through the through silicon via technology, the electrode of the bulk acoustic wave filter is led out to the electrode interface on the upper surface of the silicon substrate through the through hole, and the electrical interconnection of the electrode of the bulk acoustic wave filter, the RF interface of the functional amplifier, the circuit interface and the input and output interfaces of external radio frequency signals is realized.

The invention provides a method for preparing a chip structure of a monolithic integrated power amplifier and a bulk acoustic wave filter, which comprises the following steps:

the method comprises the following steps: manufacturing a power amplifier on a silicon substrate, and leading out an RF interface and a circuit interface;

wherein, this power amplifier includes: the circuit comprises a high-power transistor, a bias voltage circuit, an input matching circuit and an output matching circuit;

step two: packaging an upper silicon wafer on a substrate by using a eutectic bonding technology to form an upper packaging cover cap, and accommodating a power amplifier in a cavity;

step three: thinning the silicon substrate, etching a cavity at the bottom of the silicon substrate, filling a sacrificial layer, using a chemical mechanical polishing technology to realize that the sacrificial layer is parallel to the surface of the silicon substrate, and depositing/patterning a bottom electrode, a piezoelectric film, a top electrode and a mass load layer in turn to form a series resonator and a parallel resonator; the bottom electrodes of the series resonators and the parallel resonators are isolated from each other, and the top electrodes are communicated with each other;

step four: introducing an etchant through the release hole, etching off the sacrificial layer, and forming an air cavity between the substrate and the bottom electrode;

step five: etching a through hole on a silicon substrate by a through silicon via technology to lead out a filter electrode to the upper surface of the substrate, and realizing electrical interconnection with an RF interface of a power amplifier, a circuit interface and an input/output interface of an external radio frequency signal;

step six: and packaging the lower silicon wafer at the bottom of the silicon substrate by using a eutectic bonding technology to form a lower packaging cap, wherein the cavity contains the nano-filter.

The invention has the following beneficial effects: according to the chip structure and the preparation method of the monolithic integrated power amplifier and the bulk acoustic wave filter, the power amplifier and the filter at the radio frequency front end are integrated on the upper surface and the lower surface of the same substrate through the monolithic integrated power amplifier and the filter, so that the area and the volume of the radio frequency front end are effectively saved, the manufacturing cost of the radio frequency front end is reduced, and the high integration and modularization of a radio frequency system are facilitated.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic diagram of a radio frequency system;

FIG. 2 is a schematic diagram of a power amplifier configuration;

FIG. 3 is a schematic diagram of a prior art RF filter topology;

FIG. 4 is a cross-sectional view of a power amplifier after being processed on a silicon substrate in accordance with an embodiment of the present invention;

FIG. 5 is a cross-sectional view of the present invention after a first encapsulation;

FIG. 6 is a cross-sectional view of a process filter under a substrate in an embodiment of the invention;

FIG. 7 is a cross-sectional view after opening the hole in an embodiment of the present invention;

fig. 8 is a cross-sectional view after a second encapsulation in an embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The chip structure of the monolithic integrated power amplifier and the bulk acoustic wave filter of the embodiment of the invention comprises: a silicon substrate 106, a power amplifier 101, a bulk acoustic wave filter and a packaging cap; wherein:

the power amplifier 101 is disposed on the upper surface of the silicon substrate 106; the bulk acoustic wave filter is arranged on the lower surface of the silicon substrate 106 and comprises a series resonator 211 and a parallel resonator 212; the electrodes of the bulk acoustic wave filter are led out to the upper surface of the silicon substrate 106 through the through silicon via technology, so that the power amplifier 101 and the bulk acoustic wave filter are electrically interconnected;

the packaging caps are respectively arranged on the upper surface and the lower surface of the silicon substrate 106, the two packaging caps are respectively packaged through the eutectic bonding technology, cavities are formed in the upper surface and the lower surface of the silicon substrate 106, the power amplifier 101 is contained in the cavity in the upper surface, the bulk acoustic wave filter is contained in the cavity in the lower surface, and integrated packaging of devices is achieved.

The power amplifier 101 is manufactured on the upper surface of a silicon substrate 106, a through hole is etched on the silicon substrate 106 through a silicon perforation technology to lead out a bulk acoustic wave filter electrode to the upper surface of the silicon substrate 106, an RF interface 102 and a circuit interface 103, an input interface 104 and an output interface 105 of an external radio frequency signal and a filter electrode interface 207 are led out from the upper surface of the silicon substrate 106; the electrical interconnection of the bulk acoustic wave filter with the RF interface 102, the circuit interface 103 of the power amplifier 101 and the input interface 104, the output interface 105 of the external radio frequency signal is realized.

The power amplifier 101 includes a high power transistor, a bias voltage circuit, an input matching circuit, and an output matching circuit.

The packaging cap comprises an upper silicon wafer 301 arranged on the upper surface of the silicon substrate 106 and a lower silicon wafer 302 arranged on the lower surface of the silicon substrate 106, cavities are formed in the upper silicon wafer 301 and the lower silicon wafer 302, two groups of silicon wafers with the cavities are packaged with devices through a eutectic bonding technology to form the packaging cap, the power amplifier 101 is contained in the cavity of the upper silicon wafer 301, and the bulk acoustic wave filter is contained in the cavity of the lower silicon wafer 302.

The packaging cap is realized by two times of packaging, the first packaging is carried out after the manufacturing process of the power amplifier 101 on the upper surface is finished, and the second packaging is carried out after the manufacturing process of the bulk acoustic wave filter on the lower surface is finished.

Manufacturing a series resonator 211 and a parallel resonator 212 on the lower surface of the silicon substrate 106, etching a cavity on the lower surface of the silicon substrate 106, thinning the silicon substrate 106, filling the sacrificial layer 201, and realizing the parallelism of the sacrificial layer 201 and the lower surface of the silicon substrate 106 by using a chemical mechanical polishing technology; depositing/patterning a bottom electrode 202, a piezoelectric film 203, a top electrode 204 and a mass loading layer 205 on the sacrificial layer 201 in sequence to form a series resonator 211 and a parallel resonator 212; the bottom electrodes of the series resonator 211 and the parallel resonator 212 are isolated from each other, and the top electrodes are connected to each other.

The series resonator 211 and the parallel resonator 212 are provided with release holes 206, and an etchant is introduced through the release holes 206 to etch away the sacrificial layer 201 and release the sacrificial layer 201, thereby forming an air cavity 208 between the silicon substrate 106 and the bottom electrode 202.

A through hole 107 is etched on a silicon substrate 106 through a through silicon via technology, an electrode of the bulk acoustic wave filter is led out to an electrode interface 207 on the upper surface of the silicon substrate 106 through the through hole 107, and the electrode of the bulk acoustic wave filter is electrically interconnected with an RF interface 102 and a circuit interface 103 of a functional amplifier 101, and an input interface 104 and an output interface 105 of an external radio frequency signal.

The preparation method of the chip structure of the monolithic integrated power amplifier and the bulk acoustic wave filter comprises the following steps:

the method comprises the following steps: manufacturing a power amplifier on a silicon substrate, and leading out an RF interface and a circuit interface;

wherein, this power amplifier includes: the circuit comprises a high-power transistor, a bias voltage circuit, an input matching circuit and an output matching circuit;

step two: packaging an upper silicon wafer on a substrate by using a eutectic bonding technology to form an upper packaging cover cap, and accommodating a power amplifier in a cavity;

step three: thinning the silicon substrate, etching a cavity at the bottom of the silicon substrate, filling a sacrificial layer, using a chemical mechanical polishing technology to realize that the sacrificial layer is parallel to the surface of the silicon substrate, and depositing/patterning a bottom electrode, a piezoelectric film, a top electrode and a mass load layer in turn to form a series resonator and a parallel resonator; the bottom electrodes of the series resonators and the parallel resonators are isolated from each other, and the top electrodes are communicated with each other;

step four: introducing an etchant through the release hole, etching off the sacrificial layer, and forming an air cavity between the substrate and the bottom electrode;

step five: etching a through hole on a silicon substrate by a through silicon via technology to lead out a filter electrode to the upper surface of the substrate, and realizing electrical interconnection with an RF interface of a power amplifier, a circuit interface and an input/output interface of an external radio frequency signal;

step six: and packaging the lower silicon wafer at the bottom of the silicon substrate by using a eutectic bonding technology to form a lower packaging cap, wherein the cavity contains the nano-filter.

Fig. 4-7 show another embodiment of the present invention.

The resonator in the embodiment of the present invention is exemplified by a bulk acoustic wave resonator of a cavity type, and other resonators including a bulk acoustic wave resonator of a solid mount type and the like are also within a protection range.

Fig. 4 is a cross-sectional view of the power amplifier 101 after being processed on the silicon substrate 106 according to the embodiment of the present invention. The power amplifier 101 is fabricated on a silicon substrate 106, and has an RF interface 102, a circuit interface 103, input/ output interfaces 104, 105 for external RF signals, and a filter electrode interface 207.

Fig. 5 is a first packaging in the embodiment of the present invention, in which an upper silicon chip 301 is packaged on a silicon substrate 106 by using a eutectic bonding or other technique to form an upper packaging cap, and the power amplifier 101 is accommodated in a cavity.

Fig. 6 is a cross-sectional view of the series resonator 211 and the parallel resonator 212 after being processed under the silicon substrate 106 according to the embodiment of the present invention. Thinning the silicon substrate 106, etching a cavity at the bottom of the silicon substrate, filling the sacrificial layer 201, using Chemical Mechanical Polishing (CMP) and other technologies to realize that the sacrificial layer 201 is parallel to the lower surface of the silicon substrate 106, and depositing/patterning the bottom electrode 202, the piezoelectric film 203, the top electrode 204 and the mass load layer 205 in sequence to form a series resonator 211 and a parallel resonator 212; the bottom electrodes of the series resonator 211 and the parallel resonator 212 are isolated from each other, and the top electrodes are connected to each other.

Figure 7 is a cross-sectional view of the resonators 211,212 and silicon substrate 106 after being opened with holes in an embodiment of the present invention. The release holes 206 are used for releasing the sacrificial layer 201, and corrosive is introduced through the release holes 206 to corrode the sacrificial layer, so that an air cavity 208 is formed between the substrate and the bottom electrode; the through hole 107 is etched on the silicon substrate 106 through a Through Silicon Via (TSV) technology to lead out the filter electrode to an electrode interface 207 on the upper surface of the silicon substrate 106, and electrical interconnection with the RF interface 102 of the power amplifier 101, the circuit interface 103, and the input and output interfaces 104 and 105 of external radio frequency signals is realized.

Fig. 8 is a second packaging in the embodiment of the present invention, in which a lower silicon chip 302 is packaged at the bottom of the silicon substrate 106 by using eutectic bonding or the like to form a lower packaging cap, and the filter formed by the resonators 211 and 212 is accommodated in the cavity.

It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.