CN114157259B - Manufacturing method based on bandwidth-enhanced FBAR filter - Google Patents
Manufacturing method based on bandwidth-enhanced FBAR filter Download PDFInfo
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- CN114157259B CN114157259B CN202210123142.1A CN202210123142A CN114157259B CN 114157259 B CN114157259 B CN 114157259B CN 202210123142 A CN202210123142 A CN 202210123142A CN 114157259 B CN114157259 B CN 114157259B
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 17
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims abstract description 44
- 238000000576 coating method Methods 0.000 claims abstract description 24
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 8
- 238000000151 deposition Methods 0.000 claims abstract description 8
- 238000011049 filling Methods 0.000 claims abstract description 8
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 claims abstract description 6
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims abstract description 5
- 235000012239 silicon dioxide Nutrition 0.000 claims abstract description 4
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- 239000000126 substance Substances 0.000 claims description 18
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- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 description 2
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Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/64—Filters using surface acoustic waves
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
- H03H2003/023—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks the resonators or networks being of the membrane type
Abstract
The invention provides a manufacturing method of an enhanced FBAR filter based on bandwidth. Etching a cavity matrix which is symmetrically arranged on a substrate in advance; depositing silicon dioxide in the cavity matrix, and coating a lithium niobate crystal film to form a Bragg reflection layer; a bottom electrode in a cover shape is arranged above the Bragg reflection layer, covers each cavity, and is provided with a support column made of the same material as the bottom electrode; performing zinc oxide direct current magnetron sputtering between adjacent bottom electrodes to form a zinc oxide layer; wherein the filling height of the zinc oxide layer does not exceed the upper cover surface of the cover-shaped bottom electrode; preparing a dielectric layer on the zinc oxide layer; wherein the dielectric layer is formed by depositing and filling aluminum nitride; and forming a thick film layer on the dielectric layer in a direct current magnetron sputtering coating mode, and photoetching and etching the thick film layer to form the top electrode.
Description
Technical Field
The invention relates to the technical field of thin film filters, in particular to a manufacturing method based on a bandwidth-enhanced FBAR filter.
Background
At present, ultra-wideband surface acoustic wave filters have great demand in many fields, particularly in the field of communications. The ultra-bandwidth is a way to enhance the bandwidth, because the bandwidth of the filter is determined by the electromechanical coupling coefficients of the resonators, and therefore, the resonators with high electromechanical coupling coefficients are the key point for designing the ultra-bandwidth surface acoustic wave filter.
Common piezoelectric base materials of the filter comprise lithium tantalate and lithium niobate crystals, but the electromechanical coupling coefficients of the lithium tantalate and the lithium niobate crystals are low, and compared with the two piezoelectric materials, the lead niobate magnesio-acid ferroelectric crystals have extremely high electromechanical coupling coefficients.
At present, the design of a sound surface resonator based on lead magnesium niobate-lead titanate (PMN-xPT) binary ferroelectric crystal has been reported in documents, and a large electromechanical coupling coefficient can be obtained, but the Curie temperature and the phase transition temperature of PMN-xPT are low, so that the device is not beneficial to work in a high-temperature environment. However, recently, lead magnesium niobate-lead titanate (PIMN-xPT) ternary ferroelectric crystal is reported to have higher Curie temperature and phase transition temperature than PMN-xPT, but the surface acoustic wave motion speed in the crystal is lower, which is not beneficial to designing high-frequency filters. Therefore, how to design a high-frequency ultra-wideband acoustic surface filter based on the PIMN-xPT is a hot problem to be solved urgently.
Disclosure of Invention
The invention provides a manufacturing method of an FBAR filter based on bandwidth enhancement, which is used for solving the problem that recently, lead magnesium niobate-lead titanate (PIMN-xPT) ternary ferroelectric crystal is reported to have higher Curie temperature and phase transition temperature than PMN-xPT, but the surface acoustic wave in the crystal has lower movement speed and is not beneficial to designing a high-frequency filter. Therefore, how to design a high-frequency ultra-wideband acoustic surface filter based on the PIMN-xPT is a hot point problem to be solved urgently.
A manufacturing method based on a bandwidth-enhanced FBAR filter comprises the following steps:
etching a cavity matrix which is symmetrically arranged on a substrate in advance;
depositing silicon dioxide in the cavity matrix, and coating a lithium niobate crystal film to form a Bragg reflection layer;
a bottom electrode in a cover shape is arranged above the Bragg reflection layer, covers each cavity, and is provided with a support column made of the same material as the bottom electrode;
performing zinc oxide direct current magnetron sputtering between adjacent bottom electrodes to form a zinc oxide layer; wherein the content of the first and second substances,
the filling height of the zinc oxide layer does not exceed the upper cover surface of the cover-shaped bottom electrode;
preparing a dielectric layer on the zinc oxide layer; wherein the content of the first and second substances,
the dielectric layer is formed by depositing and filling aluminum nitride;
and forming a thick film layer on the dielectric layer in a direct current magnetron sputtering coating mode, and photoetching and etching the thick film layer to form the top electrode.
Further, the cavities in the cavity matrix are Y-shaped cavities, the bottoms of the Y-shaped cavities are connected, and the V angle of the Y-shaped cavities faces outwards.
Further, the top electrode is etched by graphical definition;
the top electrode is divided into a three-layer structure; wherein the content of the first and second substances,
the three-layer structure includes: the silicon-carbon-nitrogen thin film layer, the dielectric layer and the tantalum layer;
the tantalum layer in the three-layer structure is a surface layer, and a bonding pad is connected to the tantalum layer.
Furthermore, a through hole for mounting a support column is arranged on the dielectric layer;
forming a through hole sealing layer on the through hole to seal the through hole;
and forming a cavity shell passivation layer on the cavity shell, in the support pillar opening and on the through hole sealing layer, and forming an electrode lead on the cavity shell passivation layer, wherein the electrode lead is in contact with the support pillar.
Further, the method further comprises:
respectively generating a capacitor layer and an inductor layer on two sides of the surface of the substrate through graphical metal coatings;
and the capacitor layer and the inductance layer are connected through the bottom electrode and the top electrode.
Further, the method further comprises:
forming a through hole for leading out the electrode lead on the side surface of the substrate; wherein the content of the first and second substances,
the through holes comprise a first through hole and a second through hole;
forming conductive plugs in the first and second vias;
the first through hole leads out an electrode lead of the bottom electrode;
and the second through hole leads out an electrode lead of the top electrode.
Further, the method further comprises:
carrying out epitaxial layer extension on the top electrode and the substrate; wherein the content of the first and second substances,
the epitaxial layer comprises a first epitaxial layer and a second epitaxial layer;
the first epitaxial layer is arranged on the top electrode;
the second epitaxial layer is disposed on a side of the substrate.
Further, the method further comprises:
forming an isolation groove when the first epitaxial layer and the second epitaxial layer are etched;
adding a filter front assembly on the filter epitaxial structure through the isolation groove; wherein the content of the first and second substances,
the filter front face assembly comprises: a power amplifier;
and a wiring lead is arranged between the filter front assembly and the power amplifier.
Further, the method further comprises:
forming a bottom electrode and connecting leads between the bottom electrodes corresponding to different cavities on the upper surface of the Bragg reflection layer at the same time of forming the bottom electrode;
different cavities are connected in parallel through the connecting lead.
Further, the method further comprises:
forming a silicon carbon nitrogen film layer by silicon carbon nitrogen coating;
forming a thick film layer on the silicon carbon nitrogen film layer through direct current magnetron sputtering coating; wherein the content of the first and second substances,
the thick film layer is formed by mixing the dielectric layer and the tantalum layer;
graphically defining a top electrode pattern on the thick film layer;
etching the top electrode for the first time to form a conductive layer;
removing organic matters remained on the conductive layer by adopting an ashing process;
after removing the organic matter, coating the tantalum layer by photoresist;
and photoetching the tantalum layer coated with the photoresist to generate an embedded pattern of the bonding pad, and embedding the bonding pad.
The invention has the beneficial effects that: the bandwidth determining factor of the thin film filter is the electromechanical coupling coefficient, and the series resonance frequency and the parallel resonance frequency determine the coefficient. If there is only one cavity, the resonant frequency of this one cavity cannot be used to enhance the bandwidth unless the inductor is externally connected. Therefore, the invention is characterized in that the cavity matrix which can be arranged carries out power fusion through the communication incidence relation among the cavities, and achieves the purpose of enhancing the bandwidth through a power fusion mode. Finally, the zinc oxide layer of the present invention is a material with inductive properties, since it also has the purpose of enhancing the bandwidth by surrounding the cavity. Finally, the invention adopts direct current magnetron sputtering coating to form the top electrode so as to achieve the purpose of forming the complete filter.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is a flow chart of a method for manufacturing a bandwidth-enhanced FBAR filter according to an embodiment of the present invention;
fig. 2 is a diagram showing a structure of a base body of a filter manufactured in an embodiment of the present invention;
fig. 3 is a structural diagram of an FBAR filter manufactured in an embodiment of the present invention.
Detailed Description
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.
Example 1:
as shown in fig. 1, a method for manufacturing a bandwidth-based enhanced FBAR filter includes:
etching a cavity matrix which is symmetrically arranged on a substrate in advance;
depositing silicon dioxide in the cavity matrix, and coating a lithium niobate crystal film to form a Bragg reflection layer;
a bottom electrode in a cover shape is arranged above the Bragg reflection layer, covers each cavity, and is provided with a support column made of the same material as the bottom electrode;
the cover-shaped bottom electrode is a cavity matrix, and adjacent cavities are not interfered with each other, so that the bottom electrode completely meets the condition by buckling each cavity in a cover shape.
Performing zinc oxide direct current magnetron sputtering between adjacent bottom electrodes to form a zinc oxide layer; wherein, the direct current magnetron sputtering is a relatively advanced and universal technology in the prior art. This technique is convenient only for the present invention, and the zinc oxide layer is also the piezoelectric layer of the present invention.
The filling height of the zinc oxide layer does not exceed the upper cover surface of the cover-shaped bottom electrode;
preparing a piezoelectric layer on the zinc oxide layer; wherein the content of the first and second substances,
the dielectric layer is formed by depositing and filling aluminum nitride; aluminum nitride is a covalent bonding compound and therefore conveniently constitutes a dielectric layer.
And forming a thick film layer on the dielectric layer in a direct current magnetron sputtering coating mode, and photoetching and etching the thick film layer to form the top electrode.
The principle of the technical scheme is as follows: the present invention relates to a method for manufacturing an FBRA filter having a bandwidth enhancement effect, that is, a method for manufacturing a thin film filter. However, in the prior art, the bandwidth of the FBAR filter is difficult to be widened, and the FBAR filter is disclosed in the patent document: "CN 202010010060.7 a broadband thin film cavity acoustic resonator filter" also discloses: the relative bandwidth of the FBAR filter is limited by the electromechanical coupling coefficient of the piezoelectric material, and is difficult to be widened, and the relative bandwidth of the conventional FBAR filter can only reach 1-4%, so that the application range of the FBAR filter is greatly limited. If there is only one cavity, then the resonant frequency of this one cavity is fixed, otherwise bandwidth enhancement cannot be performed. In the prior art, the electromechanical coupling coefficient can be represented by the following formula:
among them, in the above-mentioned case,
the series resonance frequency is indicated;
the parallel resonance frequency is indicated;
representing the electromechanical coupling coefficient.
From the above formula, if the electromechanical coupling coefficient is to be increased, it is only possible to increase the series resonance frequency, and in the prior art, it is difficult to change the piezoelectric material due to the limitation of the piezoelectric material, most of which is zinc oxide, and the invention also adopts zinc oxide. The series resonance frequency is difficult to change, and in the prior art, in order to enhance the bandwidth, the corresponding auxiliary circuit is matched at the periphery of the filter, so as to enhance the bandwidth, but the enhanced bandwidth is extremely limited by adding the auxiliary circuit.
In order to change the series resonance frequency, as shown in fig. 2, in the present invention, 1 denotes a substrate, 2 denotes a cavity, and 3 denotes a zinc oxide layer. An increase in the parallel resonance frequency or a decrease in the capacitance of the series resonance is required to achieve bandwidth enhancement. As shown in fig. 3, 7 denotes a bragg reflective layer; 4 a lid-shaped bottom electrode; 5 denotes a support column; and 6, a top electrode having a three-layer structure. The bragg reflector 7 is a cavity etched in advance in the substrate 1, and is therefore inside the substrate.
Therefore, the invention is characterized in that the cavity matrix which can be arranged carries out parallel connection between different cavity groups through the communication incidence relation between the cavities, and the increase of the parallel resonance frequency is realized at the time, thereby achieving the purpose of enhancing the bandwidth. And aiming at each cavity group, the cavity fusion is realized by connecting in series, the series capacitance is reduced, the series resonance frequency is reduced, and the purpose of enhancing the bandwidth is achieved. Secondly, the cavity of the invention is a Y-shaped structure which is a structure for enhancing the bandwidth.
Finally, the zinc oxide layer of the present invention is a material with inductive properties, since it also has the purpose of enhancing the bandwidth by surrounding the cavity. The invention has the defects that the process is more complex and more elaborate, but the invention has the advantages that the filter manufactured by the invention can be suitable for more products, compared with the complexity of the process, the process can be streamlined, the performance of the product is difficult to improve, the application market of the product greatly improved by the invention is greatly improved, and the higher bandwidth determines that more products can adopt the filter manufactured by the invention.
Finally, the invention adopts direct current magnetron sputtering coating to form the top electrode so as to achieve the purpose of forming the complete filter.
Example 2:
preferably: the cavities in the cavity matrix are Y-shaped cavities, the bottoms of the Y-shaped cavities are connected, and the V angle of each Y-shaped cavity faces outwards.
According to the arrangement of the middle Y-shaped cavity, the passband of the filter with the Y-shaped cavity structure has wider bandwidth, and the coupling efficiency is higher during caliber coupling.
Example 3:
preferably: the top electrode is etched by graphical definition;
the top electrode is divided into a three-layer structure; wherein the content of the first and second substances,
the three-layer structure includes: the silicon-carbon-nitrogen thin film layer, the dielectric layer and the tantalum layer;
the tantalum layer in the three-layer structure is a surface layer, and a bonding pad is connected to the tantalum layer.
The top electrode has a three-layer structure, namely a silicon-carbon-nitrogen film layer, a dielectric layer and a tantalum layer; the silicon carbon nitrogen (SiCN) film is a novel ternary functional film material, and has wide application prospect in the fields of microelectronic semiconductors, computer industries and the like due to the advantages of high hardness, wide optical band gap, good high-temperature oxidation resistance, corrosion resistance and the like. The tantalum layer has the properties of storing electric quantity, charging and discharging and the like, and is mainly applied to filtering, energy storage and conversion, mark bypass, coupling and decoupling, a time constant element and the like. The performance characteristics are noticed in the application, and proper use can help to fully exert the functions thereof, wherein measures such as considering the working environment of the product and the heating temperature thereof, and taking derating use can influence the working life of the product if the product is not used properly.
Example 4:
preferably: a through hole for mounting a support pillar is arranged on the dielectric layer;
forming a through hole sealing layer on the through hole to seal the through hole;
and forming a cavity shell passivation layer on the cavity shell, in the support pillar opening and on the through hole sealing layer, and forming an electrode lead on the cavity shell passivation layer, wherein the electrode lead is in contact with the support pillar.
The through hole arranged in the invention mainly plays a role that the supporting column needs to pass through the through hole, and the bottom electrode arranged in the invention is in a cover shape, so that the problem of weak air tightness of a cavity caused by the supporting column in the prior art can be solved to a great extent; secondly, because all the bottom electrodes and the top electrodes are connected with leads to form a loop, the invention also provides the same situation, the bottom electrodes can be said to have as many cavities as many bottom electrodes, but the bottom electrodes are connected with the same lead finally, but only one top electrode is connected with the same lead.
Example 5:
preferably: the method further comprises the following steps:
respectively generating a capacitor layer and an inductor layer on two sides of the surface of the substrate through graphical metal coatings;
and the capacitor layer and the inductance layer are connected through the bottom electrode and the top electrode.
The capacitance layer and the inductance layer are arranged in the invention, so that the voltage gradient in the filter is reduced, the voltage gradient is a main source of a radio frequency field, and if the voltage gradient is too high, the radio frequency source has problems.
Example 6:
preferably: forming a through hole for leading out the electrode lead on the side surface of the substrate; wherein the content of the first and second substances,
the through holes comprise a first through hole and a second through hole;
forming conductive plugs in the first and second vias;
the first through hole leads out an electrode lead of the bottom electrode;
and the second through hole leads out an electrode lead of the top electrode.
The principle and the beneficial effects of the technical scheme are as follows: because the bottom electrode and the top electrode are led out of the electrode lead wires, the filter is provided with two through holes which are connected with the electrode lead wires through the conductive plugs, so that a loop of the bottom electrode and the top electrode is formed when the filter operates.
Example 7:
preferably: the method further comprises the following steps:
carrying out epitaxial layer extension on the top electrode and the substrate; wherein the content of the first and second substances,
the epitaxial layer comprises a first epitaxial layer and a second epitaxial layer;
the first epitaxial layer is arranged on the top electrode;
the second epitaxial layer is disposed on a side of the substrate.
The principle of the technical scheme is as follows: the invention also provides an epitaxial layer, the purpose of the epitaxial layer is to connect some peripheral circuits, in the prior art, the peripheral circuits are connected by arranging some interfaces in the epitaxial layer, but the invention mainly adopts the epitaxial layer, so that an interval exists between the peripheral circuits and the internal capacitor, the interval does not interfere with each other, but the function of the peripheral circuits is also realized.
Example 8:
preferably: the method further comprises the following steps:
forming an isolation groove when etching the first epitaxial layer and the second epitaxial layer;
adding a filter front assembly on the filter epitaxial structure through the isolation groove; wherein the filter front assembly of the present invention is mounted in the isolation recess. Of course, the front side components determine which components are present, not just the power amplifier, on a case-by-case basis.
The filter front face assembly comprises: a power amplifier;
and a wiring lead is arranged between the filter front assembly and the power amplifier.
The principle of the technical scheme is as follows: the invention is a radio frequency filter, so power amplification is an indispensable function, in the prior art, a general power amplifier is directly connected with the filter, the filter is not internally provided with the power amplifier, the invention is provided with the epitaxial layer, and the epitaxial layer can be fused with the power amplifier when a peripheral circuit is arranged, so that the power amplification function is realized.
Example 9:
preferably: the method further comprises the following steps:
forming a bottom electrode and connecting leads between the bottom electrodes corresponding to different cavities on the upper surface of the Bragg reflection layer at the same time of forming the bottom electrode;
different cavities are connected in parallel through the connecting lead.
The principle of the technical scheme is as follows: because the invention has a plurality of cavities, a plurality of cavities are connected in parallel, and the cover of the cavity is the bottom electrode, different cavities can be connected in parallel by arranging a connecting lead. The effect of increasing the series resonance frequency is achieved, meanwhile, as can be seen from the attached drawing 2, two cavities are in series butt joint, the series resonance frequency of the cavities can be reduced, and the effect of increasing and decreasing the frequency to enhance the bandwidth is achieved.
Example 10:
preferably: the method further comprises the following steps:
forming a silicon carbon nitrogen film layer by silicon carbon nitrogen coating;
forming a thick film layer on the silicon carbon nitrogen film layer through direct current magnetron sputtering coating; wherein the content of the first and second substances,
the thick film layer is formed by mixing the dielectric layer and the tantalum layer;
a top electrode pattern is defined on the thick film layer in a graphical mode;
etching the top electrode for the first time to form a conductive layer;
removing organic matters remained on the conductive layer by adopting an ashing process;
after removing the organic matter, coating the tantalum layer by photoresist;
and photoetching the tantalum layer coated with the photoresist to generate an embedded pattern of the bonding pad, and embedding the bonding pad.
The principle of the technical scheme is as follows: the top electrode processing technology is also a difficult problem, the prior art is patterned etching, and the scheme adopted by the invention is also the same, but the etching process adopted by the invention is different because the structure of the invention is different from that of the prior art.
Because the thick film layer is generated, the top electrode is formed by etching the thick film layer, the silicon carbon nitrogen film layer is formed by silicon carbon nitrogen coating in the process, and high temperature is generated by photoetching, the silicon carbon nitrogen film layer is arranged to resist photoetching high temperature and corrosion in the subsequent process. Then, the invention defines the top electrode pattern on the thick film layer in a graphical mode, namely, the etching process is the same as that in the prior art, and the conductive layer is formed. The method comprises the steps of coating a photoresist on a tantalum layer, carrying out photoetching on the tantalum layer coated with the photoresist to generate a pattern embedded into a bonding pad, directly forming a top electrode by etching in the photoetching technology in the prior art, but processing the bonding pad in a subsequent soldering mode, directly photoetching the pattern which is in line with the mounting of the bonding pad by the photoresist, fixing the bonding pad by the pattern by the thick film layer, omitting the step of soldering the bonding pad by high-temperature soldering, and simplifying part of processes.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A method for manufacturing a bandwidth-enhanced FBAR-based filter, comprising:
etching a cavity matrix which is symmetrically arranged on a substrate in advance;
depositing silicon dioxide in the cavity matrix, and coating a lithium niobate crystal film to form a Bragg reflection layer;
a bottom electrode in a cover shape is arranged above the Bragg reflection layer, covers each cavity, and is provided with a support column made of the same material as the bottom electrode;
performing zinc oxide direct current magnetron sputtering between adjacent bottom electrodes to form a zinc oxide layer; wherein the content of the first and second substances,
the filling height of the zinc oxide layer does not exceed the upper cover surface of the cover-shaped bottom electrode;
preparing a dielectric layer on the zinc oxide layer; wherein, the first and the second end of the pipe are connected with each other,
the dielectric layer is formed by depositing and filling aluminum nitride;
and forming a thick film layer on the dielectric layer in a direct current magnetron sputtering coating mode, and photoetching and etching the thick film layer to form the top electrode.
2. The method of claim 1, wherein the cavities in the cavity matrix are Y-shaped cavities, and wherein the bottoms of the Y-shaped cavities are connected, and wherein the V-angle of the Y-shaped cavities faces outward.
3. The method of claim 1, wherein the top electrode is etched by pattern definition;
the top electrode is divided into a three-layer structure; wherein the content of the first and second substances,
the three-layer structure includes: the silicon-carbon-nitrogen thin film layer, the dielectric layer and the tantalum layer; wherein the content of the first and second substances,
the silicon carbon nitrogen film layer is formed by coating silicon carbon nitrogen;
forming a thick film layer on the silicon carbon nitrogen film layer through direct current magnetron sputtering coating; the thick film layer is formed by mixing the dielectric layer and the tantalum layer;
the tantalum layer in the three-layer structure is a surface layer, and a bonding pad is connected to the tantalum layer.
4. The method of claim 1, wherein the dielectric layer has through holes for mounting support posts;
forming a through hole sealing layer on the through hole to seal the through hole;
and forming a cavity shell passivation layer on the cavity shell, in the support pillar opening and on the through hole sealing layer, and forming an electrode lead on the cavity shell passivation layer, wherein the electrode lead is in contact with the support pillar.
5. The method of manufacturing a bandwidth-enhanced FBAR filter according to claim 1, wherein said method further comprises:
respectively generating a capacitor layer and an inductor layer on two sides of the surface of the substrate through graphical metal coatings;
and the capacitor layer and the inductance layer are connected through the bottom electrode and the top electrode.
6. The method of manufacturing a bandwidth-enhanced FBAR filter in accordance with claim 4, wherein the method further comprises:
forming a through hole for leading out the electrode lead on the side surface of the substrate; wherein the content of the first and second substances,
the through holes comprise a first through hole and a second through hole;
forming conductive plugs in the first and second vias;
the first through hole leads out an electrode lead of the bottom electrode;
and the second through hole leads out an electrode lead of the top electrode.
7. The method of manufacturing a bandwidth-enhanced FBAR filter according to claim 1, wherein said method further comprises:
carrying out epitaxial layer extension on the top electrode and the substrate; wherein the content of the first and second substances,
the epitaxial layer comprises a first epitaxial layer and a second epitaxial layer;
the first epitaxial layer is arranged on the top electrode;
the second epitaxial layer is disposed on a side of the substrate.
8. The method of manufacturing a bandwidth-enhanced FBAR filter according to claim 7, wherein said method further comprises:
forming an isolation groove when the first epitaxial layer and the second epitaxial layer are etched;
adding a filter front assembly on the filter epitaxial structure through the isolation groove; wherein the content of the first and second substances,
the filter front face assembly comprises: a power amplifier;
and a wiring lead is arranged between the filter front assembly and the power amplifier.
9. The method of manufacturing a bandwidth-enhanced FBAR filter according to claim 1, wherein said method further comprises:
forming a bottom electrode and connecting leads between the bottom electrodes corresponding to different cavities on the upper surface of the Bragg reflection layer at the same time of forming the bottom electrode;
different cavities are connected in parallel through the connecting leads.
10. A method of manufacturing a bandwidth-enhanced FBAR filter according to claim 3, wherein said method further comprises:
a top electrode pattern is defined on the thick film layer in a graphical mode;
etching the top electrode for the first time to form a conductive layer;
removing organic matters remained on the conductive layer by adopting an ashing process;
after removing the organic matter, coating the tantalum layer by photoresist;
and photoetching the tantalum layer coated with the photoresist to generate an embedded pattern of the bonding pad, and embedding the bonding pad.
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| CN102315830A (en) * | 2011-04-25 | 2012-01-11 | 浙江大学 | Manufacturing method of film bulk acoustic resonator |
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| KR100473871B1 (en) * | 2000-11-13 | 2005-03-08 | 주식회사 엠에스솔루션 | Thin film resonator |
| KR100486627B1 (en) * | 2003-02-21 | 2005-05-03 | 엘지전자 주식회사 | Semiconductor package |
| US9748918B2 (en) * | 2013-02-14 | 2017-08-29 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Acoustic resonator comprising integrated structures for improved performance |
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| CN207460113U (en) * | 2017-06-14 | 2018-06-05 | 王国浩 | The thin film bulk acoustic wave resonator combined based on solid-state and cavity |
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| CN108092639A (en) * | 2017-12-21 | 2018-05-29 | 华南理工大学 | A kind of micro-nano column flexible array film bulk acoustic resonator subfilter and its preparation |
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