CN111130486A

CN111130486A - Film bulk acoustic resonator structure and manufacturing method thereof, filter and duplexer

Info

Publication number: CN111130486A
Application number: CN201911265618.XA
Authority: CN
Inventors: 唐兆云; 赖志国; 杨清华; 王家友; 唐滨
Original assignee: Beijing Hantianxia Microelectronics Co Ltd
Current assignee: Suzhou Huntersun Electronics Co Ltd
Priority date: 2019-12-11
Filing date: 2019-12-11
Publication date: 2020-05-08
Also published as: WO2021114970A1

Abstract

The invention provides a manufacturing method of a film bulk acoustic resonator structure, which comprises the following steps: determining a connection mode between the film bulk acoustic resonators to be formed; etching the substrate to form a groove and filling the groove with a sacrificial layer; forming a laminated structure covering the substrate, etching the laminated structure, forming a laminated unit above each groove and forming a first connecting part between the laminated units corresponding to the thin film bulk acoustic resonators to be formed and connected in a first connecting mode; filling the area formed by etching the laminated structure to form a filling structure; forming a first upper electrode on the laminated unit and forming a second connecting part between the first upper electrodes corresponding to the film bulk acoustic resonators to be formed and connected in a second connecting mode; etching the first connecting part; and removing the filling structure and the sacrificial layer. The invention also provides a film bulk acoustic resonator structure, a filter and a duplexer. The invention effectively reduces the acoustic loss of the device.

Description

Film bulk acoustic resonator structure and manufacturing method thereof, filter and duplexer

Technical Field

The invention relates to the technical field of semiconductors, in particular to a film bulk acoustic resonator structure, a manufacturing method thereof, a filter and a duplexer.

Background

The resonator is the core component of the filter, and the quality of the performance of the resonator directly determines the quality of the performance of the filter. Among the existing resonators, a Film Bulk Acoustic Resonator (FBAR) has a very broad application prospect in the modern wireless communication technology due to its characteristics of small volume, low insertion loss, large out-of-band rejection, high quality factor, high working frequency, large power capacity, good antistatic impact capability and the like.

Typical film bulk acoustic resonators include primarily air-gap bulk acoustic resonators, reverse etched bulk acoustic resonators, and bragg reflection bulk acoustic resonators. A method for manufacturing a thin film bulk acoustic resonator will be described below with an air gap bulk acoustic resonator as an example. Referring to fig. 1(a) to 1(h), fig. 1(a) to 1(h) are schematic cross-sectional views of stages of manufacturing a film bulk acoustic resonator according to the prior art. First, as shown in fig. 1(a), a substrate 10 is provided; next, as shown in fig. 1(b), forming a groove 11 on the substrate 10 by etching; then, as shown in fig. 1(c), a sacrificial material is deposited on the substrate 10 and is subjected to a planarization operation to form a sacrificial layer 12 within the groove 11; next, as shown in fig. 1(d), a first metal material layer 13 is deposited on the substrate 10; next, as shown in fig. 1(e), the first metal layer 13 is etched to form a lower electrode 13a on the groove 11. It should be noted that, considering that the film bulk acoustic resonator is used to form a filter, and the film bulk acoustic resonator generally forms a series/parallel relationship by the connection between the upper electrodes and the connection between the lower electrodes, when the film bulk acoustic resonator is manufactured, the connection relationship between the film bulk acoustic resonators is generally formed at the same time as the film bulk acoustic resonator is formed, so as to meet the requirement of manufacturing the filter later. Therefore, when the first metal layer 13 is etched to form the lower electrode 13a, the lower electrode which does not need to be connected is disconnected from the other lower electrodes by etching, and the lower electrode which needs to be connected is not disconnected from the other lower electrodes by etching. Next, as shown in fig. 1(f), a layer of piezoelectric material is deposited on the structure shown in fig. 1(e) to form a piezoelectric layer 14 covering the substrate 10 and the lower electrode 13 a; next, as shown in fig. 1(g), a second metallic material layer 15 is deposited on the piezoelectric layer 14; finally, as shown in fig. 1(h), the second metal material layer 15 is etched to form an upper electrode 15a above the groove 11, wherein for the upper electrode which does not need to form a connection, the connection between the upper electrode and other upper electrodes is broken by etching, and for the upper electrode which needs to form a connection, the connection between the upper electrodes is not broken by etching. Up to this point, a piezoelectric oscillating stack composed of a lower electrode, a piezoelectric layer, and an upper electrode is formed. The manufacturing method of the reverse side etching type bulk acoustic wave resonator is different from the air gap type bulk acoustic wave resonator in that: after the piezoelectric oscillating stack is formed on the substrate, etching is performed from the back surface of the substrate until the lower electrode is exposed so as to form a cavity below the lower electrode. The bragg reflector type bulk acoustic wave resonator is different from the air gap type bulk acoustic wave resonator in the following points: a Bragg reflection layer is formed on a substrate, and then the piezoelectric oscillation stack is formed on the Bragg reflection layer.

The film bulk acoustic resonator obtained based on the manufacturing method has the following defects: because the piezoelectric layers between the adjacent film bulk acoustic resonators are communicated and the piezoelectric layers in the area are directly contacted with the substrate, when the film bulk acoustic resonators work, part of acoustic waves in the piezoelectric oscillation stack can be transmitted into the substrate through the piezoelectric layers, so that acoustic wave loss of the film bulk acoustic resonators is caused, and the performance of the film bulk acoustic resonators is reduced.

Disclosure of Invention

In order to overcome the above-mentioned defects in the prior art, the present invention provides a method for manufacturing a film bulk acoustic resonator structure, the method comprising:

predetermining a connection mode between the thin film bulk acoustic resonators to be formed, wherein the connection mode comprises a first connection mode between the lower electrodes and a second connection mode between the upper electrodes;

etching the substrate to form a plurality of grooves and filling the grooves with a sacrificial layer;

forming a laminated structure covering the substrate and the sacrificial layer, wherein the laminated structure sequentially comprises a first metal material layer, a piezoelectric material layer and a second metal material layer from bottom to top;

etching the laminated structure, forming a laminated unit above each groove, and forming a first connecting part connected with the laminated unit between the laminated units corresponding to the thin film bulk acoustic resonators to be formed and connected in the first connecting mode;

filling the area formed by etching the laminated structure to form a filling structure;

forming a first upper electrode on the laminated unit, and forming a second connecting part connected with the first upper electrode between the first upper electrodes corresponding to the film bulk acoustic resonators to be formed and connected in the second connecting mode;

etching to remove the second metal material layer in the first connecting part;

and removing the filling structure and the sacrificial layer.

According to an aspect of the present invention, in the manufacturing method, the steps of etching the stacked structure, forming a stacked unit above each of the grooves, and forming a first connection portion connected to the stacked unit between the stacked units corresponding to the thin film bulk acoustic resonators to be connected in the first connection manner include: spin-coating a photoresist on the laminated structure and patterning the photoresist to form a first photoresist pattern; etching the part of the laminated structure which is not covered by the first photoresist pattern until the substrate is exposed, forming a laminated unit above each groove after the etching is finished, and forming a first connecting part connected with the laminated unit between the laminated units corresponding to the thin film bulk acoustic resonators to be formed and connected in the first connecting mode; and removing the first photoresist pattern.

According to another aspect of the present invention, in the manufacturing method, the step of filling the region formed by etching the stacked structure to form the filling structure includes: depositing a filling material on the structure obtained after the first photoresist pattern is removed until the area formed by etching the laminated structure is filled; spin-coating a photoresist on the filling material and patterning the photoresist to form a second photoresist pattern over the region; etching the part of the filling material which is not covered by the second photoresist pattern until the laminated unit is exposed so as to form a filling structure in the space; and removing the second photoresist pattern.

According to still another aspect of the present invention, in the manufacturing method, a material of the filling structure and a material of the sacrificial layer are the same.

According to still another aspect of the present invention, in the manufacturing method, the step of forming a first upper electrode on the laminated unit and forming a second connection portion connected thereto between the laminated units corresponding to the thin film bulk acoustic resonators to be formed and connected in the second connection manner includes: forming a third metal material layer covering the laminated unit, the first connecting part and the filling structure; and etching the third metal material layer, forming a first upper electrode on the laminated unit, and forming a second connecting part connected with the first upper electrode between the first upper electrodes corresponding to the thin film bulk acoustic resonators to be formed and connected in the second connecting mode.

According to still another aspect of the present invention, in the manufacturing method, the second metallic material layer and the third metallic material layer are made of the same material, wherein a thickness of the second metallic material layer is in a range of 100nm to 500nm, and a thickness of the third metallic material layer is in a range of 5nm to 300 nm.

According to still another aspect of the present invention, in the manufacturing method, the step of removing the filling structure and the sacrificial layer includes: and forming a release channel penetrating through the filling structure until the sacrificial layer is exposed, and removing the filling structure and the sacrificial layer through the release channel.

The present invention also provides a film bulk acoustic resonator structure, including:

the piezoelectric vibration sensor comprises a substrate, a plurality of piezoelectric vibration stacks formed on the substrate, a first connecting part and a second connecting part, wherein the connection modes among the piezoelectric vibration stacks comprise a first connection mode among lower electrodes and a second connection mode among upper electrodes;

a first space is formed between each piezoelectric oscillation stack and the substrate;

each piezoelectric oscillation stack sequentially comprises a lower electrode, a piezoelectric layer and an upper electrode from bottom to top, and the upper electrode sequentially comprises a second upper electrode and a first upper electrode from bottom to top;

the lower electrodes of the piezoelectric oscillating stacks connected in the first connection mode are connected through the first connection part, and the first upper electrodes of the piezoelectric oscillating stacks connected in the second connection mode are connected through the second connection part;

the area between the piezoelectric oscillating stacks except the first connecting part and the second connecting part is a second space.

The invention provides a manufacturing method of a film bulk acoustic resonator structure, which comprises the following steps:

providing a substrate and forming a laminated structure covering the substrate, wherein the laminated structure sequentially comprises a first metal material layer, a piezoelectric material layer and a second metal material layer from bottom to top;

etching the laminated structure to form a plurality of laminated units, and forming a first connecting part connected with the laminated units between the laminated units corresponding to the thin film bulk acoustic resonators to be formed and connected in the first connecting mode;

etching to remove the second metal material layer in the first connecting part;

and removing the filling structure and etching from the back surface of the substrate to form a third space below the laminated unit.

the substrate is positioned below each piezoelectric oscillation stack, and a third space penetrating through the substrate is formed;

The invention also provides a manufacturing method of the film bulk acoustic resonator structure, which comprises the following steps:

forming a Bragg reflection layer on a substrate and forming a laminated structure covering the Bragg reflection layer, wherein the laminated structure sequentially comprises a first metal material layer, a piezoelectric material layer and a second metal material layer from bottom to top;

etching to remove the second metal material layer in the first connecting part;

and removing the filling structure.

the piezoelectric resonator comprises a substrate, a Bragg reflection layer formed on the substrate, a plurality of piezoelectric oscillation stacks formed on the Bragg reflection layer, a first connecting part and a second connecting part, wherein the connecting modes among the piezoelectric oscillation stacks comprise a first connecting mode among lower electrodes and a second connecting mode among upper electrodes;

The invention also provides a filter which comprises the film bulk acoustic resonator structure.

The invention also provides a duplexer, which comprises a transmitting filter and a receiving filter, wherein the transmitting filter and/or the receiving filter are/is realized by adopting the filter.

The manufacturing method of the film bulk acoustic resonator structure provided by the invention forms the film bulk acoustic resonator and the electrode connection thereof, and also forms the space surrounding the piezoelectric oscillation stack of the film bulk acoustic resonator. Therefore, compared with the existing manufacturing method of the film bulk acoustic resonator, the method can effectively reduce the loss of the acoustic wave in the piezoelectric oscillation stack in the film bulk acoustic resonator, and is further beneficial to improving the performance of the film bulk acoustic resonator. The film bulk acoustic resonator structure formed based on the manufacturing method has the characteristics of small acoustic loss and excellent performance.

Correspondingly, the filter and the duplexer formed on the basis of the film bulk acoustic resonator structure provided by the invention also have the characteristic of excellent performance.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments made with reference to the following drawings:

fig. 1(a) to 1(h) are schematic cross-sectional views of stages in manufacturing a thin film bulk acoustic resonator according to the related art;

FIG. 2 is a flow chart of a method of fabricating a thin film bulk acoustic resonator structure according to an embodiment of the present invention;

FIGS. 3(a) to 3(t) are schematic top views of stages in the fabrication of a film bulk acoustic resonator structure according to the flow shown in FIG. 2;

FIGS. 3(a ') to 3(t ') are schematic cross-sectional views of the structures shown in FIGS. 3(a) to 3(t), respectively, taken along line AA ';

FIG. 4 is a flow chart of a method of fabricating a thin film bulk acoustic resonator structure according to another embodiment of the present invention;

FIG. 5 is a flow chart of a method of fabricating a thin film bulk acoustic resonator structure according to yet another embodiment of the present invention;

FIG. 6 is a schematic cross-sectional view of a thin film bulk acoustic resonator structure fabricated according to the process of FIG. 4;

figure 7 is a cross-sectional schematic diagram of a thin film bulk acoustic resonator structure fabricated according to the process flow shown in figure 5.

The same or similar reference numbers in the drawings identify the same or similar elements.

Detailed Description

For a better understanding and explanation of the present invention, reference will now be made in detail to the present invention as illustrated in the accompanying drawings.

The invention provides a manufacturing method of a film bulk acoustic resonator structure, in particular to a manufacturing method of an air gap bulk acoustic resonator structure. Referring to fig. 2, fig. 2 is a flow chart of a method for manufacturing a film bulk acoustic resonator structure according to an embodiment of the invention. As shown, the manufacturing method includes:

in step S101, a connection manner between the thin film bulk acoustic resonators to be formed is determined in advance, the connection manner including a first connection manner between the lower electrodes and a second connection manner between the upper electrodes;

in step S102, etching the substrate to form a plurality of grooves and filling the plurality of grooves with a sacrificial layer;

in step S103, forming a stacked structure covering the substrate and the sacrificial layer, where the stacked structure includes, from bottom to top, a first metal material layer, a piezoelectric material layer, and a second metal material layer in sequence;

in step S104, etching the stacked structure, forming a stacked unit above each of the grooves, and forming a first connection portion connected to the stacked unit between the stacked units corresponding to the thin film bulk acoustic resonators to be formed and connected in the first connection manner;

in step S105, filling a region formed by etching the stacked structure to form a filling structure;

in step S106, forming a first upper electrode on the stacked unit, and forming a second connection portion connected to the first upper electrode between the first upper electrodes corresponding to the thin film bulk acoustic resonators to be formed and connected in the second connection manner;

in step S107, etching to remove the second metal material layer in the first connection portion;

in step S108, the filling structure and the sacrificial layer are removed.

The following describes the above steps S101 to S108 in detail with reference to fig. 3(a) to 3(t) and fig. 3(a ') to 3(t '), wherein fig. 3(a) to 3(S) are schematic top views of various stages of the thin film bulk acoustic resonator manufactured according to the flow shown in fig. 2, and fig. 3(a ') to 3(t ') are schematic cross-sectional views of the structures shown in fig. 3(a) to 3(t) along the line AA '.

Specifically, in step S101, before forming the thin film bulk acoustic resonator, it is generally necessary to design the thin film bulk acoustic resonator to be formed in advance. Considering that the thin film bulk acoustic resonators are connected through the electrodes to realize series/parallel connection between the thin film bulk acoustic resonators and further form a filter, when the thin film bulk acoustic resonators to be formed are designed in advance, besides the design of the thin film bulk acoustic resonators (including the forming positions of the piezoelectric oscillation stacks, the materials and thicknesses of the upper electrodes, the piezoelectric layers and the lower electrodes in the piezoelectric oscillation stacks, and the like), the specific connection mode between the thin film bulk acoustic resonators can be determined according to the specific structure of the filter to be formed. In the present embodiment, the connection manner between the film bulk acoustic resonators includes a connection manner between the lower electrodes (hereinafter, indicated as a first connection manner) and a connection manner between the upper electrodes (hereinafter, indicated as a second connection manner). When the filter is produced according to the above-mentioned pre-design, not only the thin film bulk acoustic resonators themselves but also the connections between the thin film bulk acoustic resonators (i.e., the series/parallel connections between the thin film bulk acoustic resonators) can be formed, which facilitates the formation of the subsequent filter.

In step S102, first, as shown in fig. 3(a) and 3 (a'), a substrate 100 is provided. In the present embodiment, the material of the substrate 100 is silicon (Si). It is understood by those skilled in the art that the material of the substrate 100 is silicon, which is only a preferred embodiment, and in other embodiments, the material of the substrate 100 may also be a semiconductor material such as germanium, silicon germanium, and the like. For the sake of brevity, all possible materials for substrate 100 are not enumerated here. Typically, the thickness of the substrate 100 ranges from 750 μm to 850 μm, such as 750 μm, 800 μm, 850 μm, and the like.

Next, as shown in fig. 3(b) and 3 (b'), the substrate 100 is etched to form a groove 101. Here, when the groove 101 is drawn in fig. 3 (b'), only the opening edge of the groove 101 is drawn to illustrate the groove 101. It should be noted that, in general, a plurality of thin film bulk acoustic resonators are often formed on the substrate, and therefore, the number of grooves formed by etching the substrate corresponds to the number of thin film bulk acoustic resonators to be formed on the substrate. It will be understood by those skilled in the art that the number, position, shape, etc. of the grooves formed on the substrate are determined by actual design requirements, and the 4 grooves 101 shown in fig. 3(b) and 3 (b') are only schematic examples given for the purpose of illustrating the present invention. Hereinafter, the 4 grooves 101 shown in fig. 3(B) and 3 (B') are respectively denoted by a groove a, a groove B, a groove C, and a groove D from left to right. Accordingly, 4 thin film bulk acoustic resonators will be formed on the substrate 100, wherein the thin film bulk acoustic resonators formed on the grooves a, B, C, and D will be hereinafter referred to as a thin film bulk acoustic resonator a, a thin film bulk acoustic resonator B, a thin film bulk acoustic resonator C, and a thin film bulk acoustic resonator D, respectively. In the present embodiment, the connection manner between the film bulk acoustic resonators is predetermined as follows: the film bulk acoustic resonator A and the film bulk acoustic resonator B are connected in a second connection mode (namely, connected between upper electrodes), the film bulk acoustic resonator B and the film bulk acoustic resonator C are connected in a second connection mode (namely, connected between the upper electrodes), and the film bulk acoustic resonator C and the film bulk acoustic resonator D are connected in a first connection mode (namely, connected between the lower electrodes). It will be understood by those skilled in the art that the connection mode between the film bulk acoustic resonators is determined by the actual design requirements of the filter, and the connection mode between the film bulk acoustic resonators is merely an illustrative example given for the purpose of illustrating the present invention.

Next, as shown in fig. 3(c) and 3 (c'), a sacrificial layer 102 is deposited on the substrate 100 to fill the groove 101. Here, since the groove 101 cannot be directly seen from a top view, an opening edge of the groove 101 is shown by a dotted line in fig. 3 (c'). It should also be noted that, for structures that are not visible from the top, their edges are indicated by dashed lines. In the present embodiment, the sacrificial layer 102 is silicon nitride (SiN). It should be noted that the sacrificial layer is not limited to silicon nitride, and other suitable materials may be selected according to actual design requirements, and any material that can ensure the sacrificial layer to have etching selectivity in the subsequent step of releasing the sacrificial layer is suitable for the present invention.

Finally, as shown in fig. 3(d) and 3 (d'), the planarization operation is performed on the sacrificial layer 102 until the upper surface of the sacrificial layer 102 in the groove 101 is flush with the upper surface of the substrate 100 and the thickness of the sacrificial layer 102 in the groove 101 meets a desired range. In the present embodiment, the thickness of the sacrificial layer 102 in the groove 101 after the planarization operation is in the range of 1.5 μm to 4 μm, such as 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, and the like.

Preferably, as shown in fig. 3(e) and 3 (e'), after filling the sacrificial layer 102 in the groove 101, a seed layer 103 is deposited on the substrate 100 and the sacrificial layer 102, and the seed layer 103 covers the upper surfaces of the substrate 100 and the sacrificial layer 102. In the present embodiment, the material of the seed layer 103 is aluminum nitride (AlN). It will be understood by those skilled in the art that the material of the seed layer is not limited to aluminum nitride, but may be other materials in other embodiments, and for the sake of brevity, all possible materials of the seed layer are not listed here. Further, in the present embodiment, the thickness of the seed layer 103 ranges from 5nm to 30nm, for example, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, and the like.

The following steps will be explained on the basis of the structures shown in fig. 3(e) and 3 (e').

In step S103, first, as shown in fig. 3(f) and 3 (f'), a first metal material layer 104 covering the seed layer 103 is formed by deposition, wherein the first metal material layer 104 is subsequently used for forming a lower electrode. Here, in the case where the seed layer 103 is not formed, the first metal material layer 104 covering the substrate 100 and the sacrificial layer 102 may be formed by deposition. In the present embodiment, the first metallic material layer 104 is preferably implemented using molybdenum (Mo). It will be understood by those skilled in the art that the material of the first metallic material layer is not limited to molybdenum, and any material suitable for forming an electrode is suitable for the first metallic material layer in the present invention, and for the sake of brevity, all possible materials of the first metallic material layer are not listed again. In addition, in the present embodiment, the thickness of the first metal material layer 104 ranges from 100nm to 500 nm.

Next, as shown in fig. 3(g) and 3 (g'), a layer of piezoelectric material is deposited on the first metallic material layer 104 to form a piezoelectric material layer 105 covering the first metallic material layer 104, wherein the piezoelectric material layer 105 is subsequently used to form a piezoelectric layer. In the present embodiment, the piezoelectric material layer 105 is implemented using aluminum nitride (AlN). It will be understood by those skilled in the art that the material of the piezoelectric material layer is not limited to aluminum nitride, and any material suitable for forming the piezoelectric layer is suitable for the piezoelectric material layer in the present invention, and for the sake of brevity, all possible materials of the piezoelectric material layer are not listed here. Further, in the present embodiment, the thickness of the piezoelectric material layer 105 ranges from 300nm to 2 μm.

Next, as shown in fig. 3(h) and 3 (h'), a second metal material layer 106 is formed by deposition to cover the piezoelectric material layer 105, wherein the second metal material layer 106 is subsequently used for forming an upper electrode. In the present embodiment, the second metallic material layer 106 is preferably implemented using molybdenum (Mo). It will be understood by those skilled in the art that the material of the second metallic material layer is not limited to molybdenum, and any material suitable for forming an electrode is suitable for the second metallic material layer in the present invention, and for the sake of brevity, all possible materials of the second metallic material layer are not listed again. In addition, in the present embodiment, the thickness of the second metal material layer 106 is in a range of 100nm to 500 nm.

Hereinafter, a structure composed of the seed layer 103, the first metal material layer 104, the piezoelectric material layer 105, and the second metal material layer 106 is referred to as a stacked structure. If the first metal material layer 104 is formed directly after the sacrificial layer 102 is formed (that is, if the seed layer 103 is not formed), the structure formed by the first metal material layer 104, the piezoelectric material layer 105, and the second metal material layer 106 is referred to as a stacked structure.

In step S104, first, as shown in fig. 3(i) and 3 (i'), a protective layer 107 covering the upper surface thereof is deposited on the second metallic material layer 106. In the present embodiment, the protective layer 107 is preferably silicon dioxide (SiO)₂) And (5) realizing. It will be understood by those skilled in the art that the material of the protection layer 107 is not limited to silicon dioxide, and any material that can protect the second metal material layer from the photoresist that is spin-coated on the second metal material layer is suitable for the protection layer in the present invention, and for the sake of brevity, all possible materials of the protection layer are not listed here. Further, in the present embodiment, the thickness of the protective layer 107 ranges from 10nm to 200 nm. It should be noted that the formation of the protective layer 107 on the second metal material layer 106 is a preferred step. The following steps will be explained on the basis of the structures shown in fig. 3(i) and 3 (i').

Next, as shown in fig. 3(j) and 3 (j'), a photoresist is spin-coated on the protective layer 107, and the photoresist is patterned to form a photoresist pattern (hereinafter, represented by a first photoresist pattern). The first photoresist pattern includes a first pattern 108a and a second pattern 108 b. The number of the first patterns 108a is the same as the number of the thin film bulk acoustic resonators to be formed (i.e., the same as the number of the grooves 101 on the substrate 100), wherein one first pattern 108a is formed above each groove 101. In addition, for the first pattern 108a above each groove 101, the specific shape of the first pattern 108a is determined by the thin film bulk acoustic resonator to be formed on the groove 101. The second pattern 108b is formed between the first patterns 108a corresponding to the thin film bulk acoustic resonators to be connected by the first connection means, and is connected to the first patterns 108 a. In particular, in the present embodiment, as shown in fig. 3(j) and 3 (j'), the first pattern 108a is formed above the four grooves, and the second pattern 108b is formed between the first patterns 108a corresponding to the thin film bulk acoustic resonator C and the thin film bulk acoustic resonator D to be formed. It should be noted that the boundary between the first graphic 108a and the second graphic 108b in fig. 3(j) and 3 (j') is drawn artificially, and the boundary does not exist in the actual manufacturing process only to make the reader clearly understand the specific areas of the first graphic 108a and the second graphic 108 b. It should be further noted that spin-coating a photoresist and patterning it to form a photoresist pattern covering a predetermined area is a conventional technique of those skilled in the art, and for the sake of brevity, will not be described in detail herein.

Next, as shown in fig. 3(k) and 3 (k'), the portion of the stacked structure not covered by the first photoresist pattern is etched until the substrate 100 is exposed by using the first photoresist pattern as a mask. After the etching is completed, a portion of the stacked structure under the first pattern 108a and the second pattern 108b is retained, wherein a portion under the first pattern 108a is hereinafter referred to as a stacked unit, and a portion under the second pattern 108b is hereinafter referred to as a connection portion (hereinafter referred to as a first connection portion). That is, after the etching is finished, a stacked unit is formed below each first pattern 108a (i.e., above each recess), and a first connection portion connected to the stacked unit is formed between the stacked units corresponding to the thin film bulk acoustic resonators to be connected in the first connection manner. Specifically, in the present embodiment, as shown in fig. 3 (k'), stacked units, which are respectively represented by stacked unit a, stacked unit B, stacked unit C, and stacked unit D, are formed above each of groove a, groove B, groove C, and groove D. The laminated units a and B are not connected to other laminated units, and the laminated unit C and the laminated unit D (i.e., the laminated units corresponding to the thin film bulk acoustic resonator C and the thin film bulk acoustic resonator D to be formed) are connected to each other by the first connection unit.

Finally, as shown in fig. 3(l) and 3 (l'), the first photoresist pattern is removed. It should be noted that how to remove the photoresist pattern is a known technique, and for the sake of brevity, the description is omitted here. After removing the first photoresist pattern, the upper surfaces of the stack unit and the first connection part are exposed.

In step S105, the region formed by etching the stacked structure is filled to form a filling structure. In this embodiment, the filling structure is formed as follows:

first, as shown in fig. 3(m) and 3(m '), a filling material 120 is deposited on the resulting structure after the first photoresist pattern is removed (i.e., the structure shown in fig. 3(l) and 3 (l')) until the region 109 formed by etching the stacked structure is filled.

Next, as shown in fig. 3(n) and 3 (n'), a photoresist is spin-coated on the filling material 120 and patterned to form a photoresist pattern 121 (hereinafter, represented as a second photoresist pattern 121) over the region 109. That is, in the present embodiment, a portion of the filling material 120 located above the stacked structure and the first connection portion is exposed, and the other portion is covered by the second photoresist pattern.

Next, as shown in fig. 3(o) and 3 (o'), the region not covered by the second photoresist pattern is etched until the stacked unit and the upper surface of the first connection portion are exposed, so as to form a filling structure 120a filling the region 109. In this embodiment, the filling material 120 and the protection layer 107 need to be etched until the upper surfaces of the stacked units and the first connection portions are exposed. For the case where the protection layer 107 is not formed, the filling material 120 only needs to be etched until the upper surfaces of the stacked unit and the first connection portion are exposed.

Finally, as shown in fig. 3(p) and 3 (p'), the second photoresist pattern is removed.

It should be noted that the material of the filling structure 120a (i.e., the filling material 120) is not limited in any way in the present invention. Since the filling structure 120a is removed after the piezoelectric oscillation stack of the film bulk acoustic resonator is formed, any material that is easy to remove and does not affect other structures (piezoelectric oscillation stack, substrate, etc.) of the film bulk acoustic resonator during the removal process can be used for the implementation of the filling structure 120 a. Preferably, the material of the filling structure 120a (i.e., the filling material 120) and the material of the sacrificial layer 102 are the same, i.e., both are silicon nitride (SiN) in the present embodiment.

In step S106, first, as shown in fig. 3(q) and 3(q '), a layer of metal material is deposited on the structure shown in fig. 3(p) and 3 (p') to form a third metal material layer 122 covering the stacked units, the first connection portions, and the filling structures 120 a. The third metal material layer 122 is preferably made of the same material as the second metal material layer 106, and in this embodiment, is molybdenum (Mo). It will be understood by those skilled in the art that the material of the third metallic material layer 122 is not limited to molybdenum, and any material suitable for forming an electrode is suitable for the third metallic material layer 122 in the present invention, and for the sake of brevity, all possible materials of the third metallic material layer 122 are not listed. In addition, in the present embodiment, the thickness of the third metal material layer 122 ranges from 5nm to 300 nm.

Next, as shown in fig. 3(r) and 3 (r'), the third metal material layer 122 is etched to form a first upper electrode 123a on the stacked unit, and a connection portion 123b (hereinafter, referred to as a second connection portion 123 b) connected to the first upper electrode 123a between the first upper electrodes 123a corresponding to the thin film bulk acoustic resonators to be connected in the second connection manner. In this embodiment, the first upper electrode 123a and the second connection portion 123b may be formed by first spin-coating a photoresist on the third metal material layer 122 and patterning the photoresist to form a photoresist pattern, and then etching a region not covered by the photoresist pattern. For the thin film bulk acoustic resonator to be formed to be connected in the first connection manner, the third metal material layer 122 is etched so that the first connection portion is exposed. Specifically, as shown in fig. 3(r), first upper electrodes 123a are formed above the stacked cell a, the stacked cell B, the stacked cell C, and the stacked cell D, wherein the first upper electrodes 123a above the stacked cell a and the stacked cell B are connected by a second connection portion 123B, the first upper electrodes 123a above the stacked cell B and the stacked cell C are connected by a second connection portion 123B, and the first upper electrodes 123a above the stacked cell C and the stacked cell D are disconnected.

Preferably, after the third metallic material layer 122 is formed, a layer of passivation material may also be deposited on the third metallic material layer 122 to form a passivation material layer (not shown) covering the third metallic material layer 122. The layer of passivation material may be implemented using aluminum nitride (AlN) with a thickness in the range of 100nm to 300 nm. Accordingly, for the case of forming the passivation material layer, the passivation material layer and the third metal material layer 122 need to be etched to form the first upper electrode 123a and the second connection portion 123 b.

In step S107, as shown in fig. 3(S) and 3 (S'), the second metal material layers 106 in the first connection portion are etched away, so that the stacked units connected by the first connection portion are disconnected between the second metal material layers 106. Specifically to the present embodiment, as shown in fig. 3(s), the second metal material layer 106 in the stacked cell C and the second metal material layer 106 in the stacked cell D are disconnected. Preferably, the etching of the piezoelectric material layer 105 in the first connection portion may also be continued until the first metal material layer 104 in the first connection portion is exposed.

Up to this point, the piezoelectric oscillating stack of the film bulk acoustic resonator is formed entirely. For each thin film bulk acoustic resonator to be formed, the first metal material layer 104 in the corresponding stacked unit is a lower electrode of the piezoelectric oscillation stack, the piezoelectric material layer 105 is a piezoelectric layer of the piezoelectric oscillation stack, and the second metal material layer 106 is a second upper electrode, and forms an upper electrode of the piezoelectric oscillation stack together with the first upper electrode 123a located above the stacked unit. In addition, the piezoelectric oscillation stack is formed, and meanwhile, the connection between the film bulk acoustic resonators is also formed. For the film bulk acoustic resonator to be formed and connected in the second connection mode, the upper electrodes of the film bulk acoustic resonator are connected through the second connection part 123 b; for the film bulk acoustic resonator to be formed and connected in the first connection manner, the lower electrodes of the film bulk acoustic resonator are connected through the first metal material layer 104 in the first connection portion.

In step S108, as shown in fig. 3(t) and 3 (t'), the filling structure 120a and the sacrificial layer 102 are removed. In the present embodiment, the material of the filling structure 120a and the sacrificial layer 102 are the same, and based on this, by reasonably designing the groove 101 such that the groove 101 includes an extension (not shown) communicating with the body portion of the groove and extending to the lower side of the filling structure 120a besides the body portion of the groove, so that the etching is performed from the position of the filling structure 120a corresponding to the extension of the groove 101 to the lower side until reaching the extension of the groove 101, a release channel (not shown) penetrating the filling structure 120a and exposing the sacrificial layer 102 can be formed. The filling structure 120a and the sacrificial layer 102 can be removed at one time by using an etching solution through the release passage. The removal of the filling structures 120a and the sacrificial layer 102 is not limited to the above-mentioned manner, and for the sake of brevity, all the manners of removing the filling structures 120a and the sacrificial layer 102 are not listed. In addition, the etching solution may be selected according to the specific materials of the filling structure 120a and the sacrificial layer 102, which is not limited herein. As shown in fig. 3 (t'), after the sacrificial layer 102 is removed, a space 125 (hereinafter, referred to as a first space 125) is formed in a region where the sacrificial layer 102 is located, that is, a space is formed below the piezoelectric oscillation stack. After the filling structure 120a is removed, a space 124 (hereinafter, referred to as a second space 124) is formed in the area where the filling structure 120a is located, that is, a space is formed in the area surrounding the piezoelectric oscillation stack. And finishing the manufacturing of the film bulk acoustic resonator structure.

Compared with the existing manufacturing method of the air-gap bulk acoustic resonator structure, the method can form the space surrounding the piezoelectric oscillation stack of the air-gap bulk acoustic resonator while forming the air-gap bulk acoustic resonator and the electrode connection of the air-gap bulk acoustic resonator. Therefore, the loss of the acoustic wave in the piezoelectric oscillation stack can be effectively reduced, and the performance of the air-gap type bulk acoustic wave resonator is improved.

Correspondingly, the invention also provides a film bulk acoustic resonator structure, in particular an air gap bulk acoustic resonator structure. The film bulk acoustic resonator structure provided by the invention comprises:

Next, each constituent part of the film bulk acoustic resonator structure will be described in detail with reference to fig. 3(t) and 3 (t'). Fig. 3(t) is a schematic top view of a film bulk acoustic resonator structure according to an embodiment of the present invention, and fig. 3(t ') is a schematic cross-sectional view of the structure shown in fig. 3(t) along line AA'.

Specifically, as shown in fig. 3(t) and 3 (t'), the film bulk acoustic resonator structure provided by the present invention includes a substrate 100. In the present embodiment, the material of the substrate 100 is silicon (Si). It is understood by those skilled in the art that the material of the substrate 100 is silicon, which is only a preferred embodiment, and in other embodiments, the material of the substrate 100 may also be a semiconductor material such as germanium, silicon germanium, and the like. For the sake of brevity, all possible materials for substrate 100 are not enumerated here. Typically, the thickness of the substrate 100 ranges from 750 μm to 850 μm, such as 750 μm, 800 μm, 850 μm, and the like.

The film bulk acoustic resonator provided by the present invention further includes a plurality of piezoelectric oscillating stacks formed on the substrate 100. The connection mode between the piezoelectric oscillation stacks comprises a first connection mode between the lower electrodes and a second connection mode between the upper electrodes. A first space 125 is formed between each piezoelectric oscillating stack and the substrate 100. In the present embodiment, the depth of the first space 125 ranges from 1.5 μm to 4 μm, for example, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, and the like.

Each piezoelectric oscillation stack includes, from bottom to top, a lower electrode 104, a piezoelectric layer 105, and an upper electrode. In the present embodiment, the material of the lower electrode 104 is molybdenum (Mo), and the thickness thereof ranges from 100nm to 300 nm. The material of the piezoelectric layer 105 is aluminum nitride (AlN) with a thickness in the range of 300nm to 2 μm. In the present embodiment, the upper electrode includes the second upper electrode 106 and the first upper electrode 123a in sequence from bottom to top. Preferably, the first upper electrode 123a and the second upper electrode 106 are made of the same material and are both molybdenum (Mo). The thickness of the first upper electrode 123a ranges from 5nm to 300nm, and the thickness of the second upper electrode 106 ranges from 100nm to 500 nm.

The film bulk acoustic resonator structure further includes a first connection portion and a second connection portion 123 b.

In this embodiment, first connecting portion includes lower electrode connecting portion and piezoelectric layer connecting portion from bottom to top in proper order, wherein, the material and the thickness of lower electrode connecting portion are the same with the material and the thickness of lower electrode 104, the material and the thickness of piezoelectric layer connecting portion are the same with the material and the thickness of piezoelectric layer 105, first connecting portion are located between the piezoelectric oscillation stack that connects with first connected mode, lower electrode connecting portion and piezoelectric layer connecting portion in first connecting portion form the connection respectively with lower electrode 104 and piezoelectric layer 105 of this piezoelectric oscillation stack to realize being connected between the piezoelectric oscillation stack lower electrode. In other embodiments, the first connection portion may also include only a lower electrode connection portion that forms a connection with the piezoelectric stack lower electrode 106, and the material and thickness of the lower electrode connection portion are the same as those of the lower electrode 104.

The second connection portion 123b is disposed between the first upper electrodes 123a of the piezoelectric oscillation stacks connected in the second connection manner, and forms a connection with the first upper electrodes 123a to achieve the connection between the electrodes of the piezoelectric oscillation stacks. In the present embodiment, the material and thickness of the second connection part 123b are the same as those of the first upper electrode 123 a.

For each piezoelectric oscillation stack, there is no other connection between the piezoelectric oscillation stack and the other piezoelectric oscillation stack except that the lower electrode 104 forms a lower electrode connection with the other piezoelectric oscillation stack through the first connection portion, and/or the first upper electrode 123a forms an upper electrode connection with the other piezoelectric oscillation stack through the second connection portion 123 b. That is, the area between the plurality of piezoelectric oscillating stacks on the substrate 100 except for the first connection portion and the second connection portion 123b appears as the second space 124.

Preferably, the thin film bulk acoustic resonator structure provided by the present invention further includes a seed layer 103, and the seed layer 103 is formed between the piezoelectric oscillation stack and the substrate 100. In the present embodiment, the material of the seed layer 103 is aluminum nitride (AlN), and the thickness thereof is in a range of 5nm to 30nm, for example, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, and the like.

Preferably, the thin film bulk acoustic resonator provided by the present invention further includes a passivation layer (not shown) formed on the upper electrode and the second connection portion 123 b. In this embodiment, the passivation layer is implemented using aluminum nitride (AlN) having a thickness ranging from 100nm to 300 nm.

Compared with the existing air-gap bulk acoustic resonator structure, in the air-gap bulk acoustic resonator structure provided by the invention, the areas between the air-gap bulk acoustic resonators except the electrode connecting parts are all represented as spaces. Therefore, the loss of the acoustic wave in the piezoelectric oscillation stack can be effectively reduced, and the performance of the air-gap type bulk acoustic wave resonator is improved.

The invention also provides a manufacturing method of the film bulk acoustic resonator structure, in particular to a manufacturing method of a reverse etching bulk acoustic resonator structure. Referring to fig. 4, fig. 4 is a flow chart of a method for manufacturing a film bulk acoustic resonator structure according to another embodiment of the invention. As shown, the manufacturing method includes:

in step S201, a connection manner between the thin film bulk acoustic resonators to be formed is determined in advance, the connection manner including a first connection manner between the lower electrodes and a second connection manner between the upper electrodes;

in step S202, providing a substrate and forming a stacked structure covering the substrate, wherein the stacked structure sequentially includes a first metal material layer, a piezoelectric material layer, and a second metal material layer from bottom to top;

in step S203, etching the stacked structure to form a plurality of stacked units, and forming a first connection portion connected to the stacked units between the stacked units corresponding to the thin film bulk acoustic resonators to be formed and connected in the first connection manner;

in step S204, filling a region formed by etching the stacked structure to form a filling structure;

in step S205, forming a first upper electrode on the stacked unit, and forming a second connection portion connected to the first upper electrode between the first upper electrodes corresponding to the thin film bulk acoustic resonators to be formed and connected in the second connection manner;

in step S206, etching to remove the second metal material layer in the first connection portion;

in step S207, the filling structure is removed and etched from the back side of the substrate to form a third space under the stacked unit.

Next, the contents of step S201 to step S207 will be described in detail.

Specifically, step S201 is the same as step S101 in the foregoing, and therefore, the contents of the corresponding parts in the foregoing can be referred to.

In step S202, the material and parameters of the substrate can refer to the related contents related to the substrate 100 in step S102. The step of forming the stacked structure covering the substrate may refer to the corresponding content regarding the formation of the stacked structure in the previous step S103.

In step S203, the stacked structure is etched to form a plurality of stacked units, and a first connection portion connected to the stacked units is formed between the stacked units corresponding to the thin film bulk acoustic resonators to be formed and connected in a first connection manner. The method for forming the stacked unit and the first connection portion can refer to the corresponding contents of the step S104 regarding the formation of the stacked unit and the first connection portion.

Step S204 is the same as step S105, step S205 is the same as step S106, and step S206 is the same as step S107, so that reference can be made to the contents of the corresponding parts.

In step S207, the filling structure is removed using an etching solution and etched from the back surface of the substrate to form a space (hereinafter, referred to as a third space) under the stacked unit. The step of etching from the back side of the substrate to form the third space under the stacked cells is a routine technique for those skilled in the art and will not be described in detail herein for the sake of brevity.

Compared with the existing manufacturing method of the reverse-side etched bulk acoustic resonator structure, the method can form a space surrounding the reverse-side etched bulk acoustic resonator piezoelectric oscillating stack while forming the reverse-side etched bulk acoustic resonator and the electrode connection of the reverse-side etched bulk acoustic resonator. Therefore, the loss of the acoustic wave in the piezoelectric oscillation stack can be effectively reduced, and the performance of the reverse etching type acoustic wave resonator is improved.

Correspondingly, the invention also provides a film bulk acoustic resonator structure, which comprises:

Next, each constituent part of the film bulk acoustic resonator structure will be described in detail with reference to fig. 6. Fig. 6 is a schematic cross-sectional view of a film bulk acoustic resonator structure according to another embodiment of the present invention.

Specifically, as shown in fig. 6, the film bulk acoustic resonator structure provided by the present invention includes a substrate 100 and a plurality of piezoelectric oscillating stacks located on the substrate 100, wherein a third space 126 penetrating through the substrate is formed below each piezoelectric oscillating stack of the substrate 100. The connection mode between the piezoelectric oscillation stacks comprises a first connection mode between the lower electrodes and a second connection mode between the upper electrodes.

Each piezoelectric oscillation stack includes, from bottom to top, a lower electrode 104, a piezoelectric layer 105, and an upper electrode. Further, the upper electrode includes the second upper electrode 106 and the first upper electrode 123a in this order from bottom to top.

The second connection portion 123b is disposed between the first upper electrodes 123a of the piezoelectric oscillation stacks connected in the second connection manner, and forms a connection with the first upper electrodes 123a to achieve the connection between the electrodes of the piezoelectric oscillation stacks. In the present embodiment, the material and thickness of the second connection part 123a are the same as those of the first upper electrode 123 a.

Preferably, the thin film bulk acoustic resonator structure provided by the present invention further includes a seed layer 103, and the seed layer 103 is formed between the piezoelectric oscillation stack and the substrate 100.

Preferably, the thin film bulk acoustic resonator provided by the present invention further includes a passivation layer (not shown) formed on the upper electrode and the second connection portion 123 b.

For the materials and parameters of the substrate 100, the seed layer 103, the lower electrode 104, the piezoelectric layer 105, the first upper electrode 123a, the second upper electrode, and the passivation layer, reference may be made to the description of the corresponding parts in the structure shown in fig. 3 (t'), and for the sake of brevity, the description is omitted here.

Compared with the conventional reverse-side etched bulk acoustic resonator structure, in the reverse-side etched bulk acoustic resonator structure provided by the invention, the regions except the electrode connecting part between the reverse-side etched bulk acoustic resonators are all in a space. Therefore, the loss of the acoustic wave in the piezoelectric oscillation stack can be effectively reduced, and the performance of the reverse etching type acoustic wave resonator is improved.

The invention also provides a manufacturing method of the film bulk acoustic resonator structure, in particular to a manufacturing method of the Bragg reflection type bulk acoustic resonator structure. Referring to fig. 5, fig. 5 is a flow chart of a method for manufacturing a film bulk acoustic resonator structure according to another embodiment of the invention. As shown, the manufacturing method includes:

in step S301, a connection manner between the thin film bulk acoustic resonators to be formed is determined in advance, the connection manner including a first connection manner between the lower electrodes and a second connection manner between the upper electrodes;

in step S302, a bragg reflection layer and a stacked structure covering the bragg reflection layer are formed on a substrate, wherein the stacked structure sequentially includes a first metal material layer, a piezoelectric material layer, and a second metal material layer from bottom to top;

in step S303, etching the stacked structure to form a plurality of stacked units, and forming a first connection portion connected to the stacked units between the stacked units corresponding to the thin film bulk acoustic resonators to be formed and connected in the first connection manner;

in step S304, filling a region formed by etching the stacked structure to form a filling structure;

in step S305, forming a first upper electrode on the stacked unit, and forming a second connection portion connected to the first upper electrode between the first upper electrodes corresponding to the thin film bulk acoustic resonators to be formed and connected in the second connection manner;

in step S306, etching to remove the second metal material layer in the first connection portion;

in step S307, the filling structure is removed.

Next, the contents of step S301 to step S307 will be described in detail.

Specifically, step S301 is the same as step S101 in the foregoing, so that the contents of the corresponding parts in the foregoing can be referred to.

In step S302, a substrate is provided and a bragg reflective layer is formed on the substrate. The material and parameters of the substrate may be referred to the related contents related to the substrate 100 in the step S102, and the step of forming the bragg reflector layer on the substrate is a conventional technique of a person skilled in the art, and for the sake of brevity, the material, parameters, and forming process of the substrate and the bragg reflector layer will not be described herein. The step of forming the stacked structure covering the bragg reflector layer can refer to the corresponding content regarding the formation of the stacked structure in the previous step S103.

In step S303, the stacked structure is etched to form a plurality of stacked units, and a first connection portion connected to the stacked units is formed between the stacked units corresponding to the thin film bulk acoustic resonators to be connected in the first connection manner. The method for forming the stacked unit and the first connection portion can refer to the corresponding contents of the step S104 regarding the formation of the stacked unit and the first connection portion.

Step S304 is the same as step S105, step S305 is the same as step S106, and step S306 is the same as step S107, so the contents of the corresponding parts in the above description can be referred to.

In step S307, the filling structure may be removed by using an etching solution.

Compared with the conventional manufacturing method of the Bragg reflection type bulk acoustic wave resonator structure, the method can form the Bragg reflection type bulk acoustic wave resonator and the electrode connection thereof, and simultaneously form the space surrounding the piezoelectric oscillation stack of the Bragg reflection type bulk acoustic wave resonator. Therefore, the loss of the sound wave in the piezoelectric oscillation stack can be effectively reduced, and the performance of the Bragg reflection type bulk acoustic wave resonator is improved.

Next, each constituent part of the above-described film bulk acoustic resonator structure will be described in detail with reference to fig. 7. Fig. 7 is a schematic cross-sectional view of a film bulk acoustic resonator structure according to another embodiment of the present invention.

Specifically, as shown in fig. 7, the thin film bulk acoustic resonator provided by the present invention includes a substrate 100, a bragg reflection layer 127 located on the substrate 100, and a piezoelectric resonator stack located on the bragg reflection layer 127. The bragg reflector layer 127 includes high and low acoustic impedance layers alternately disposed. The specific materials and thickness ranges of the high/low acoustic impedance layers may be arranged as conventional bragg reflectors in the art. The connection mode between the piezoelectric oscillation stacks comprises a first connection mode between the lower electrodes and a second connection mode between the upper electrodes.

Compared with the conventional Bragg reflection type bulk acoustic wave resonator structure, the Bragg reflection type bulk acoustic wave resonator structure provided by the invention has the advantages that the regions between the Bragg reflection type bulk acoustic wave resonators except for the electrode connecting parts are all represented as spaces. Therefore, the loss of the sound wave in the piezoelectric oscillation stack can be effectively reduced, and the performance of the Bragg reflection type bulk acoustic wave resonator is improved.

The invention also provides a filter which comprises the film bulk acoustic resonator structure provided by the invention. For the sake of brevity, the structure of the film bulk acoustic resonator provided by the present invention is not described repeatedly, and the structure thereof can refer to the content of the relevant parts in the foregoing. Compared with the film bulk acoustic resonator in the prior art, the film bulk acoustic resonator structure provided by the invention has better device performance, so that compared with the existing filter formed based on the existing film bulk acoustic resonator structure, the filter formed based on the film bulk acoustic resonator structure provided by the invention has better performance.

The invention also provides a duplexer, which comprises a transmitting filter and a receiving filter, wherein the transmitting filter and/or the receiving filter are/is realized by adopting the filter provided by the invention. For the sake of brevity, the filter provided by the present invention will not be described repeatedly, and the structure thereof can refer to the content of the relevant part in the foregoing. Compared with the existing duplexer formed based on the existing filter, the duplexer formed based on the filter provided by the invention has better performance.

The scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, and means described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, or means.

Claims

1. A method of manufacturing a film bulk acoustic resonator structure, the method comprising:

etching to remove the second metal material layer in the first connecting part;

and removing the filling structure and the sacrificial layer.

2. The manufacturing method according to claim 1, wherein the steps of etching the laminated structure, forming a laminated unit above each of the grooves, and forming a first connection portion connected thereto between the laminated units corresponding to the thin film bulk acoustic resonators to be connected in the first connection manner include:

spin-coating a photoresist on the laminated structure and patterning the photoresist to form a first photoresist pattern;

etching the part of the laminated structure which is not covered by the first photoresist pattern until the substrate is exposed, forming a laminated unit above each groove after the etching is finished, and forming a first connecting part connected with the laminated unit between the laminated units corresponding to the thin film bulk acoustic resonators to be formed and connected in the first connecting mode;

and removing the first photoresist pattern.

3. The manufacturing method according to claim 2, wherein the step of filling the region formed by etching the stacked structure to form a filling structure comprises:

depositing a filling material on the structure obtained after the first photoresist pattern is removed until the area formed by etching the laminated structure is filled;

spin-coating a photoresist on the filling material and patterning the photoresist to form a second photoresist pattern over the region;

etching the part of the filling material which is not covered by the second photoresist pattern until the laminated unit is exposed so as to form a filling structure in the area;

and removing the second photoresist pattern.

4. The manufacturing method according to claim 3, wherein a material of the filling structure and a material of the sacrificial layer are the same.

5. The manufacturing method according to claim 1, wherein the step of forming a first upper electrode on the laminated unit and forming a second connecting portion connected thereto between the laminated units corresponding to the thin film bulk acoustic resonators to be formed connected in the second connecting manner includes:

forming a third metal material layer covering the laminated unit, the first connecting part and the filling structure;

and etching the third metal material layer, forming a first upper electrode on the laminated unit, and forming a second connecting part connected with the first upper electrode between the first upper electrodes corresponding to the thin film bulk acoustic resonators to be formed and connected in the second connecting mode.

6. The manufacturing method according to claim 1, wherein:

the second metal material layer and the third metal material layer are made of the same material, wherein the thickness of the second metal material layer ranges from 100nm to 500nm, and the thickness of the third metal material layer ranges from 5nm to 300 nm.

7. The manufacturing method according to claim 1, wherein the step of removing the filling structure and the sacrificial layer comprises:

and forming a release channel penetrating through the filling structure until the sacrificial layer is exposed, and removing the filling structure and the sacrificial layer through the release channel.

8. A thin film bulk acoustic resonator structure, comprising:

9. The thin film bulk acoustic resonator of claim 8, wherein:

the first upper electrode and the second upper electrode are made of the same material, wherein the thickness of the first upper electrode ranges from 5nm to 300nm, and the thickness of the second upper electrode ranges from 100nm to 500 nm.

10. A method of manufacturing a film bulk acoustic resonator structure, the method comprising:

etching to remove the second metal material layer in the first connecting part;

11. A thin film bulk acoustic resonator structure, comprising:

12. A method of manufacturing a film bulk acoustic resonator structure, the method comprising:

etching to remove the second metal material layer in the first connecting part;

and removing the filling structure.

13. A thin film bulk acoustic resonator structure, comprising:

14. A filter comprising a thin film bulk acoustic resonator structure as claimed in any one of claims 8, 11, 13.

15. A duplexer comprising a transmit filter and a receive filter, wherein the transmit filter and/or the receive filter are implemented using the filter of claim 14.