CN216146307U - Air cavity type film bulk acoustic resonator filter and filter assembly - Google Patents
Air cavity type film bulk acoustic resonator filter and filter assembly Download PDFInfo
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- CN216146307U CN216146307U CN202121483370.7U CN202121483370U CN216146307U CN 216146307 U CN216146307 U CN 216146307U CN 202121483370 U CN202121483370 U CN 202121483370U CN 216146307 U CN216146307 U CN 216146307U
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Abstract
The utility model relates to the technical field of filters, and provides an air cavity type film bulk acoustic resonator filter and a filter assembly, wherein the filter comprises an input terminal, an output terminal, a plurality of film bulk acoustic resonators connected in series and a plurality of film bulk acoustic resonators connected in parallel; the plurality of series thin film bulk acoustic resonators include first to sixth thin film bulk acoustic resonators connected in series between an input terminal and an output terminal; the plurality of film bulk acoustic resonators connected in parallel comprise seventh to tenth film bulk acoustic resonators, one ends of the seventh, eighth and tenth film bulk acoustic resonators are respectively connected to nodes between the first film bulk acoustic resonator and the second film bulk acoustic resonator, between the third film bulk acoustic resonator and the fourth film bulk acoustic resonator, and between the fifth film bulk acoustic resonator and the sixth film bulk acoustic resonator, and the ninth film bulk acoustic resonator and the eighth film bulk acoustic resonator are connected in series to allow signals with specific frequencies to pass through.
Description
Technical Field
The utility model belongs to the technical field of filters, and particularly relates to an air cavity type film bulk acoustic resonator filter and a filter assembly.
Background
In recent years, with the continuous development of 5G wireless communication technology, mobile communication is realized by utilizing higher frequency bands and frequency band recombination, which puts increasing demands on miniaturization, high frequency bandwidth, integration and flexibility of relevant radio frequency components.
Film Bulk Acoustic Resonator (FBAR) filters are gradually replacing traditional surface Acoustic wave filters and ceramic filters by virtue of their excellent characteristics of small size, high resonant frequency, high quality factor, large power capacity, good roll-off effect and the like, and have a larger and larger market share in the field of radio frequency filters, and play a great role in the field of 5G wireless communication radio frequencies.
However, most of the research on the film bulk acoustic resonator filter is focused on the manufacturing method, and the research on the specific structure of the film bulk acoustic resonator filter is less.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides an air cavity type film bulk acoustic resonator filter and a filter component, and aims to provide a novel structure of the film bulk acoustic resonator filter.
In a first aspect, an embodiment of the present invention provides an air cavity type thin film bulk acoustic resonator filter with a center frequency of 3660MHz, including an input terminal, an output terminal, a plurality of thin film bulk acoustic resonators connected in series, and a plurality of thin film bulk acoustic resonators connected in parallel;
the plurality of series thin film bulk acoustic resonators comprise a first thin film bulk acoustic resonator, a second thin film bulk acoustic resonator, a third thin film bulk acoustic resonator, a fourth thin film bulk acoustic resonator, a fifth thin film bulk acoustic resonator and a sixth thin film bulk acoustic resonator which are connected in series between the input terminal and the output terminal;
the plurality of film bulk acoustic resonators connected in parallel comprise a seventh film bulk acoustic resonator, an eighth film bulk acoustic resonator, a ninth film bulk acoustic resonator and a tenth film bulk acoustic resonator, one end of the seventh film bulk acoustic resonator is connected to a node between the first film bulk acoustic resonator and the second film bulk acoustic resonator, one end of the eighth film bulk acoustic resonator is connected to a node between the third film bulk acoustic resonator and the fourth film bulk acoustic resonator, one end of the ninth film bulk acoustic resonator is connected to the other end of the eighth film bulk acoustic resonator, and one end of the tenth film bulk acoustic resonator is connected to a node between the fifth film bulk acoustic resonator and the sixth film bulk acoustic resonator; and the other ends of the seventh film bulk acoustic resonator, the ninth film bulk acoustic resonator and the tenth film bulk acoustic resonator are respectively connected with a grounding terminal.
The filter in the embodiment of the present invention includes a plurality of thin film bulk acoustic resonators connected in series between an input terminal and an output terminal, and a plurality of thin film bulk acoustic resonators connected in parallel between nodes of the plurality of thin film bulk acoustic resonators connected in series. The signal passing input terminal can allow the signal with specific frequency to pass after passing through the plurality of thin film bulk acoustic resonators connected in series and the plurality of thin film bulk acoustic resonators connected in parallel.
With reference to the first aspect, in one possible implementation manner, the series resonance frequency and the parallel resonance frequency of the plurality of series thin film bulk acoustic resonators are the same; the series resonance frequency and the parallel resonance frequency of the plurality of film bulk acoustic resonators connected in parallel are the same.
With reference to the first aspect, in one possible implementation manner, the series resonance frequency of the plurality of series thin film bulk acoustic resonators is the same as the parallel resonance frequency of the plurality of parallel thin film bulk acoustic resonators.
With reference to the first aspect, in one possible implementation manner, the area of the first film bulk acoustic resonator is 5950 μm2-6050μm2The areas of the second film bulk acoustic resonator and the third film bulk acoustic resonator are both 3450 μm2-3550μm2The areas of the fourth film bulk acoustic resonator, the fifth film bulk acoustic resonator and the tenth film bulk acoustic resonator are all 3350 μm2-3450μm2The area of the sixth film bulk acoustic resonator is 5250 mu m2-5350μm2The area of the seventh film bulk acoustic resonator is 8350 mu m2-8450μm2What is, what isThe area of the eighth film bulk acoustic resonator and the ninth film bulk acoustic resonator is 3750 μm2-3850μm2。
With reference to the first aspect, in a possible implementation manner, a layout of the air cavity type thin film bulk acoustic resonator filter includes a sacrificial layer, a lower electrode layer, an upper electrode layer, a difference frequency layer, and a hole layer, where the difference frequency layer corresponds to the plurality of thin film bulk acoustic resonators connected in parallel, and the plurality of thin film bulk acoustic resonators connected in series do not have the difference frequency layer; the hole layer is provided with a plurality of release holes, each film bulk acoustic resonator is provided with a plurality of release channels, and each release channel at least corresponds to one release hole.
With reference to the first aspect, in one possible implementation manner, the thickness of the upper electrode layer is
The thickness of the lower electrode layer is
The thickness of the difference frequency layer is
The diameter of the release hole is 15-25 μm, the air cavity type film bulk acoustic resonator filter further comprises a piezoelectric layer, and the thickness of the piezoelectric layer is
With reference to the first aspect, in a possible implementation manner, the plurality of parallel thin film bulk acoustic resonators further includes an eleventh thin film bulk acoustic resonator, one end of the eleventh thin film bulk acoustic resonator is connected in series with the ninth thin film bulk acoustic resonator, and the other end of the eleventh thin film bulk acoustic resonator is connected to the ground terminal.
With reference to the first aspect, in one possible implementation manner, the seventh thin film bulk acoustic resonator and the tenth thin film bulk acoustic resonator are located on a first side of a straight line where the input terminal and the output terminal are located, the eighth thin film bulk acoustic resonator, the ninth thin film bulk acoustic resonator and the eleventh thin film bulk acoustic resonator are located on a second side of the straight line, and the first side and the second side of the straight line are opposite;
the center connecting lines of the first thin film bulk acoustic resonator, the second thin film bulk acoustic resonator and the third thin film bulk acoustic resonator form a first V shape, the center connecting lines of the third thin film bulk acoustic resonator, the fourth thin film bulk acoustic resonator and the fifth thin film bulk acoustic resonator form a second V shape, the center connecting lines of the fourth thin film bulk acoustic resonator, the fifth thin film bulk acoustic resonator and the sixth thin film bulk acoustic resonator form a third V shape, the opening angles of the first V shape and the third V shape are all larger than 90 degrees, the opening angle of the second V shape is smaller than 90 degrees, the opening directions of the first V shape and the third V shape are all towards the second side of the straight line, and the opening direction of the second V shape is towards the first side of the straight line;
the centers of the second thin film bulk acoustic resonator, the third thin film bulk acoustic resonator, and the fourth thin film bulk acoustic resonator are located on a straight line, and the centers of the first thin film bulk acoustic resonator and the sixth thin film bulk acoustic resonator are located on a straight line where the input terminal and the output terminal are located.
With reference to the first aspect, in a possible implementation manner, the layout of the air cavity type thin film bulk acoustic resonator filter includes first to sixteenth layout areas;
the first layout area, the third layout area and the fifth layout area are grounding terminal layout areas, the second layout area is an input terminal layout area, the fourth layout area is an output terminal layout area, the third layout area is positioned at the upper part of the layout of the filter, and the first layout area, the fifth layout area, the second layout area and the fourth layout area are respectively and symmetrically arranged at two sides of the layout of the filter;
a sixth layout area, a seventh layout area, an eighth layout area, a ninth layout area, a tenth layout area, and a eleventh layout area are respectively layout areas of the first thin film bulk acoustic resonator, the second thin film bulk acoustic resonator, the third thin film bulk acoustic resonator, the fourth thin film bulk acoustic resonator, the fifth thin film bulk acoustic resonator, and the sixth thin film bulk acoustic resonator; the sixth layout area, the seventh layout area, the eighth layout area, the ninth layout area, the tenth layout area and the eleventh layout area are respectively connected in series between the second layout area and the fourth layout area;
a twelfth version area, a thirteenth version area, a fourteenth version area, a fifteenth version area and a sixteenth version area are respectively the layout areas of the seventh film bulk acoustic resonator, the eighth film bulk acoustic resonator, the ninth film bulk acoustic resonator, the tenth film bulk acoustic resonator and the eleventh film bulk acoustic resonator;
the twelfth layout area is positioned at the lower part of the sixth layout area, one end of the twelfth layout area is respectively connected with the sixth layout area and the seventh layout area, and the other end of the twelfth layout area is connected with the first layout area;
the thirteenth layout area is positioned at the upper part of the eighth layout area, one end of the thirteenth layout area is respectively connected with the eighth layout area and the ninth layout area, the other end of the thirteenth layout area is connected with one end of the fourteenth layout area, the other end of the fourteenth layout area is connected with one end of the sixteenth layout area, and the other end of the sixteenth layout area is connected with the third layout area;
the fifteenth layout area is positioned at the lower part of the eleventh layout area, one end of the fifteenth layout area is respectively connected with the tenth layout area and the eleventh layout area, and the other end of the fifteenth layout area is connected with the fifth layout area.
In a second aspect, embodiments of the present invention further provide a filter assembly, including an air cavity type thin film bulk acoustic resonator filter as described in any one of the above.
Drawings
Fig. 1 is a schematic circuit diagram of an air cavity type film bulk acoustic resonator filter according to an embodiment of the present invention;
fig. 2 is a schematic circuit diagram of another air cavity type film bulk acoustic resonator filter according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a layout structure of an air cavity type film bulk acoustic resonator filter according to an embodiment of the present invention;
fig. 4 is a schematic layout view of a sacrificial layer of the air cavity type thin film bulk acoustic resonator filter shown in fig. 3;
fig. 5 is a layout diagram of a lower electrode layer of the air cavity type thin film bulk acoustic resonator filter shown in fig. 3;
fig. 6 is a schematic layout of the upper electrode layer of the air cavity type tfbaw resonator filter shown in fig. 3;
fig. 7 is a layout diagram of a difference frequency layer of the air cavity type thin film bulk acoustic resonator filter shown in fig. 3;
fig. 8 is a layout diagram of an aperture layer of the air cavity type thin film bulk acoustic resonator filter shown in fig. 3;
fig. 9 is an amplitude-frequency characteristic curve of the air cavity type thin film bulk acoustic resonator filter according to the embodiment of the present invention.
In the figure: 11-input terminal, 12-output terminal, 21-first film bulk acoustic resonator, 22-second film bulk acoustic resonator, 23-third film bulk acoustic resonator, 24-fourth film bulk acoustic resonator, 25-fifth film bulk acoustic resonator, 26-sixth film bulk acoustic resonator, 31-seventh film bulk acoustic resonator, 32-eighth film bulk acoustic resonator, 33-ninth film bulk acoustic resonator, 34-tenth film bulk acoustic resonator, 35-eleventh film bulk acoustic resonator, 41-release hole.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model.
Film Bulk Acoustic Resonator (FBAR) filters are gradually replacing traditional Surface Acoustic Wave (SAW) filters and ceramic filters, and play a great role in the field of radio frequency of wireless communication. However, most of the existing research on the FBAR filter focuses on the preparation method, and the research on the specific structure is less. In certain engineering application, a filter with the center frequency of 3750MHz needs to be used, the 1dB bandwidth of the filter is more than 35MHz, and the suppression at 3650MHz and the suppression at 3850MHz need to be respectively more than 40dBc and 35 dBc.
In view of the above problems, embodiments of the present invention provide an air cavity type thin film bulk acoustic resonator filter. The air cavity type film bulk acoustic resonator filter comprises an input terminal, an output terminal, a plurality of film bulk acoustic resonators connected in series and a plurality of film bulk acoustic resonators connected in parallel; the plurality of series thin film bulk acoustic resonators comprise a first thin film bulk acoustic resonator, a second thin film bulk acoustic resonator, a third thin film bulk acoustic resonator, a fourth thin film bulk acoustic resonator, a fifth thin film bulk acoustic resonator and a sixth thin film bulk acoustic resonator which are connected in series between an input terminal and an output terminal; the plurality of film bulk acoustic resonators connected in parallel comprise a seventh film bulk acoustic resonator, an eighth film bulk acoustic resonator, a ninth film bulk acoustic resonator and a tenth film bulk acoustic resonator, one end of the seventh film bulk acoustic resonator is connected to a node between the first film bulk acoustic resonator and the second film bulk acoustic resonator, one end of the eighth film bulk acoustic resonator is connected to a node between the third film bulk acoustic resonator and the fourth film bulk acoustic resonator, one end of the ninth film bulk acoustic resonator is connected to the other end of the eighth film bulk acoustic resonator, and one end of the tenth film bulk acoustic resonator is connected to a node between the fifth film bulk acoustic resonator and the sixth film bulk acoustic resonator; the other ends of the seventh film bulk acoustic resonator, the ninth film bulk acoustic resonator and the tenth film bulk acoustic resonator are connected to a ground terminal, respectively.
The filter in the embodiment of the present invention includes a plurality of thin film bulk acoustic resonators connected in series between an input terminal and an output terminal, and a plurality of thin film bulk acoustic resonators connected in parallel between nodes of the plurality of thin film bulk acoustic resonators connected in series. After the signals pass through the plurality of thin film bulk acoustic resonators connected in series and the plurality of thin film bulk acoustic resonators connected in parallel through the input terminal, filtering of a specific frequency band of the signals can be realized, and therefore the signals with specific central frequency are output.
Fig. 1 shows a schematic circuit diagram of an air cavity type film bulk acoustic resonator filter according to an embodiment of the present invention. The air cavity type film bulk acoustic resonator filter comprises an input terminal 11, an output terminal 12, a plurality of film bulk acoustic resonators connected in series and a plurality of film bulk acoustic resonators connected in parallel. The plurality of series thin film bulk acoustic resonators include a first thin film bulk acoustic resonator 21, a second thin film bulk acoustic resonator 22, a third thin film bulk acoustic resonator 23, a fourth thin film bulk acoustic resonator 24, a fifth thin film bulk acoustic resonator 25, and a sixth thin film bulk acoustic resonator 26. The plurality of parallel thin film bulk acoustic resonators include a seventh thin film bulk acoustic resonator 31, an eighth thin film bulk acoustic resonator 32, a ninth thin film bulk acoustic resonator 33, and a tenth thin film bulk acoustic resonator 34.
Among them, the first thin film bulk acoustic resonator 21, the second thin film bulk acoustic resonator 22, the third thin film bulk acoustic resonator 23, the fourth thin film bulk acoustic resonator 24, the fifth thin film bulk acoustic resonator 25, and the sixth thin film bulk acoustic resonator 26 are connected in series between the input terminal 11 and the output terminal 12, and the first thin film bulk acoustic resonator 21 to the sixth thin film bulk acoustic resonator 26 have the same first series resonance frequency and first parallel resonance frequency.
The film bulk acoustic resonators connected in series are divided into four serial arm resonators which are respectively a first serial arm resonator, a second serial arm resonator, a third serial arm resonator and a fourth serial arm resonator. The first series arm resonator includes a first thin film bulk acoustic resonator 21, the second series arm resonator includes a second thin film bulk acoustic resonator 22 and a third thin film bulk acoustic resonator 23, the third series arm resonator includes a fourth thin film bulk acoustic resonator 24 and a fifth thin film bulk acoustic resonator 25, and the fourth series arm resonator includes a sixth thin film bulk acoustic resonator 26. The second serial arm resonator and the third serial arm resonator adopt a structure that two resonators are connected in series, so that the area of the resonators can be increased, the resonators can be in a range in which the process is easy to realize, and the reliability of the filter is improved.
The film bulk acoustic resonators connected in parallel are divided into three parallel-arm resonators, namely a first parallel-arm resonator, a second parallel-arm resonator and a third parallel-arm resonator. The first parallel-arm resonator includes a seventh thin film bulk acoustic resonator 31, the second parallel-arm resonator includes an eighth thin film bulk acoustic resonator 32 and a ninth thin film bulk acoustic resonator 33, and the third parallel-arm resonator includes a tenth thin film bulk acoustic resonator 34.
The seventh thin film bulk acoustic resonator 31 has one end connected to a node between the first thin film bulk acoustic resonator 21 and the second thin film bulk acoustic resonator 22, and the other end connected to a ground terminal. The eighth thin film bulk acoustic resonator 32 has one end connected to a node between the third thin film bulk acoustic resonator 23 and the fourth thin film bulk acoustic resonator 24, and the other end connected to a ground terminal. The tenth thin film bulk acoustic resonator 34 has one end connected to a node between the fifth thin film bulk acoustic resonator 25 and the sixth thin film bulk acoustic resonator 26, and the other end connected to a ground terminal. The ninth thin film bulk acoustic resonator 33 is connected in series with the eighth thin film bulk acoustic resonator 32, so that the area of the resonators can be increased within a range in which the process is easily implemented, and the reliability of the filter can be improved.
As shown in fig. 2, in the present application, in order to implement a narrow-band design, the plurality of parallel thin film bulk acoustic resonators further includes an eleventh thin film bulk acoustic resonator 35, one end of the eleventh thin film bulk acoustic resonator 35 is connected in series with the ninth thin film bulk acoustic resonator 33, and the other end of the eleventh thin film bulk acoustic resonator 35 is connected to a ground terminal. As such, the second parallel-arm resonator includes the eighth thin film bulk acoustic resonator 32, the ninth thin film bulk acoustic resonator 33, and the eleventh thin film bulk acoustic resonator 35. The seventh to tenth thin film bulk acoustic resonators 31 to 34 have the same second series resonance frequency and second parallel resonance frequency, and the eleventh thin film bulk acoustic resonator 34 has the same first series resonance frequency and first parallel resonance frequency as the first to sixth thin film bulk acoustic resonators 21 to 26.
In some embodiments, the series resonance frequency and the parallel resonance frequency of the plurality of series thin film bulk acoustic resonators are the same; the series resonance frequency and the parallel resonance frequency of the film bulk acoustic resonators connected in parallel are the same. That is, the plurality of first series resonance frequencies are the same, the plurality of first parallel resonance frequencies are the same, the plurality of second series resonance frequencies are the same, and the plurality of second parallel resonance frequencies are the same.
In some embodiments, the series resonance frequency of the plurality of series thin film bulk acoustic resonators is the same as the parallel resonance frequency of the plurality of parallel thin film bulk acoustic resonators. That is, the first series resonance frequency and the second parallel resonance frequency are the same, so that a specific center frequency can be formed.
In some embodiments, the area of the film bulk acoustic resonator should be controlled to 4000 μm in consideration of the easiness of process implementation2-80000μm2In particular, it may be 4000 μm2、42000μm2、80000μm2And the like. In the same circuit, the area difference of each film bulk acoustic resonator in the circuit should be as small as possible in the design of each film bulk acoustic resonator, and the difference is generally less than 4 times.
In some embodiments, in order to obtain an air cavity type thin film bulk acoustic resonator filter of a specific center frequency, it may be implemented by adjusting the areas and positions of the first to eleventh thin film bulk acoustic resonators 21 to 35. The film bulk acoustic resonator filter may be configured to have a symmetrical structure or may be configured to have an asymmetrical structure. The area of the resonator is the overlapping area of the upper electrode and the lower electrode of the parallel plate capacitor of the resonator.
Illustratively, the area of the first film bulk acoustic resonator 21 is 5950 μm in order to obtain a filter with a center frequency of 3750MHz2-6050μm2Specifically, it may be 5950 μm2、6000μm2、6050μm2Equal in value, the areas of the second film bulk acoustic resonator 22 and the third film bulk acoustic resonator 23 are all 3450 μm2-3550μm2Specifically, it may be 3450 μm2、3500μm2、3550μm2Equal in value, the areas of the fourth film bulk acoustic resonator 24, the fifth film bulk acoustic resonator 25 and the tenth film bulk acoustic resonator 34 are all 3350 μm2-3450μm2Specifically, it may be 3350 μm2、3400μm2、3450μm2Equivalent value, the area of the sixth film bulk acoustic resonator 26 is 5250 μm2-5350μm2It may be 5250 μm2、5300μm2、5350μm2Equivalent value, the area of the seventh film bulk acoustic resonator 31 is 8350 μm2-8450μm2Specifically, it may be 8350 μm2、8400μm2、8450μm2Equivalent value, the area of the eighth film bulk acoustic resonator 32 and the ninth film bulk acoustic resonator 33 is 3750 μm2-3850μm2Specifically, it may be 3750 μm2、3800μm2、3850μm2Equivalent value, the eleventh film bulk acoustic resonator 35 has an area of 8350 μm2-8450μm2Specifically, it may be 8350 μm2、8400μm2、8450μm2And the like.
In some embodiments, the layout of the air cavity type thin film bulk acoustic resonator filter includes a sacrificial layer, a lower electrode layer, an upper electrode layer, a difference frequency layer and an aperture layer, the difference frequency layer corresponds to a plurality of thin film bulk acoustic resonators connected in parallel, and the plurality of thin film bulk acoustic resonators connected in series do not have the difference frequency layer. The difference frequency layer is used for realizing the frequency difference between the film bulk acoustic resonators connected in parallel and the film bulk acoustic resonators connected in series, so that a filter is formed, and the filtering of the phase specific frequency is realized. In general, the second series resonance frequency and the second parallel resonance frequency of the thin film bulk acoustic resonators connected in parallel are lower than the first series resonance frequency and the first parallel resonance frequency of the thin film bulk acoustic resonators connected in series, and the first series resonance frequency is equal to the second parallel resonance frequency.
In order to form an air cavity of the film bulk acoustic resonator and realize the reflection of acoustic waves, an orifice layer is specially arranged, a plurality of release holes are arranged in the orifice layer, and each release channel of each film bulk acoustic resonator corresponds to at least one release hole.
For example, each resonator may have a plurality of release channels (e.g., five), one release hole for each release channel, and release gas may enter the release channels through the release holes, then enter the sacrificial layer region to etch the sacrificial layer material away into gas, and then be exhausted through the release channels and the release holes. In addition, if the space of the filter is tight, two release channels can share one release hole. In addition, the air cavity type film bulk acoustic resonator filter further includes a piezoelectric layer, the piezoelectric layer covers the whole chip, and in a probe test area, a probe (for example, a GSG probe) needs to be used for testing the chip, so that the piezoelectric layer needs to be etched away, and a lower electrode is exposed for testing.
In some embodiments, to obtain a filter of a particular center frequency, this can be achieved by adjusting the thicknesses of the upper electrode, the lower electrode, and the piezoelectric layer.
Illustratively, to obtain a filter having a center frequency of 3660MHz, the upper electrode layer has a thickness of
Specifically, can be
Equal value, thickness of lower electrode layer of
Specifically, can be
Of equal value, a thickness of the piezoelectric layer of
Specifically, can be
And the like.
Illustratively, the difference frequency layer has a thickness of
Specifically, can be
And the like.
Illustratively, the diameter of the release hole is 15 μm to 25 μm, and specifically, the diameter may be 15 μm, 20 μm, 25 μm, or the like.
The total layout of the air cavity type film bulk acoustic resonator filter with the center frequency of 3750MHz provided by the embodiment of the utility model is shown in FIG. 3.
In some embodiments, the total layout of the filter in fig. 3 includes first through sixteenth layout areas. The first layout area 401, the third layout area 403 and the fifth layout area 405 are ground terminal layout areas, the second layout area 402 is a layout area of the input terminal 11, the fourth layout area 404 is a layout area of the output terminal 12, the third layout area 403 is located at the upper part of the layout of the filter, and the first layout area 401, the fifth layout area 405, the second layout area 402 and the fourth layout area 404 are respectively and symmetrically arranged at two sides of the layout of the filter.
A sixth layout area 406, a seventh layout area 407, an eighth layout area 408, a ninth layout area 409, a tenth layout area 410, and an eleventh layout area 411 are layout areas of the first thin film bulk acoustic resonator 21, the second thin film bulk acoustic resonator 22, the third thin film bulk acoustic resonator 23, the fourth thin film bulk acoustic resonator 24, the fifth thin film bulk acoustic resonator 25, and the sixth thin film bulk acoustic resonator 26, respectively. The sixth layout area 406, the seventh layout area 407, the eighth layout area 408, the ninth layout area 409, the tenth layout area 410, and the eleventh layout area 411 are respectively connected in series between the second layout area 401 and the fourth layout area 404.
A twelfth layout area 412, a thirteenth layout area 413, a fourteenth layout area 414, a fifteenth layout area 415, and a sixteenth layout area 416 are layout areas of the seventh thin film bulk acoustic resonator 31, the eighth thin film bulk acoustic resonator 32, the ninth thin film bulk acoustic resonator 33, the tenth thin film bulk acoustic resonator 34, and the eleventh thin film bulk acoustic resonator 35, respectively.
The twelfth layout area 412 is located below the sixth layout area 406, and has one end connected to the sixth layout area 406 and the seventh layout area 407, respectively, and the other end connected to one end of the first layout area 401; the thirteenth version area 413 is located on the eighth version area 408, and one end of the thirteenth version area 413 is connected to the eighth version area 408 and the ninth version area 409 respectively, the other end of the thirteenth version area is connected to one end of the fourteenth version area 414, and the other end of the fourteenth version area 414 is connected to one end of the sixteenth version area 416; the other end of the sixteenth version area 416 is connected to the third version area 403; the fifteenth layout area 415 is located below the eleventh layout area 411, and has one end connected to the tenth layout area 410 and the eleventh layout area 411, respectively, and the other end connected to the fifth layout area 405.
Illustratively, the seventh thin film bulk acoustic resonator 31 and the tenth thin film bulk acoustic resonator 34 are located on a first side of a straight line on which the input terminal 11 and the output terminal 12 are located, and the eighth thin film bulk acoustic resonator 32, the ninth thin film bulk acoustic resonator 33, and the eleventh thin film bulk acoustic resonator 35 are located on a second side of the straight line, where the first side and the second side of the straight line are opposite.
The central connecting lines of the first thin film bulk acoustic resonator 21, the second thin film bulk acoustic resonator 22 and the third thin film bulk acoustic resonator 23 form a first V shape, the central connecting lines of the third thin film bulk acoustic resonator 23, the fourth thin film bulk acoustic resonator 24 and the fifth thin film bulk acoustic resonator 25 form a second V shape, the central connecting lines of the fourth thin film bulk acoustic resonator 24, the fifth thin film bulk acoustic resonator 25 and the sixth thin film bulk acoustic resonator 26 form a third V shape, the opening angles of the first V shape and the third V shape are both larger than 90 degrees, the opening angle of the second V shape is smaller than 90 degrees, the opening directions of the first V shape and the third V shape are both towards the second side of the straight line, and the opening direction of the second V shape is towards the first side of the straight line.
The centers of the second thin film bulk acoustic resonator 22, the third thin film bulk acoustic resonator 23, and the fourth thin film bulk acoustic resonator 24 are located on a straight line, and the centers of the first thin film bulk acoustic resonator 21 and the sixth thin film bulk acoustic resonator 26 are located on a straight line on which the input terminal 11 and the output terminal 12 are located. It will be appreciated that the alignment may be complete or substantially aligned.
Specifically, the layout to be used in the process of manufacturing the 3750MHz air cavity type film bulk acoustic resonator filter mainly includes a layout of a sacrificial layer, a layout of a lower electrode, a layout of an upper electrode, a layout of a difference frequency layer, and a layout of a hole layer, as shown in fig. 3 to 8.
Fig. 4 is a layout of a sacrifice layer in which the first thin film bulk acoustic resonator 21 to the eleventh thin film bulk acoustic resonator 35 are respectively disposed. The first sacrificial patterning area 501, the second sacrificial patterning area 502, the third sacrificial patterning area 503, the fourth sacrificial patterning area 504, the fifth sacrificial patterning area 505 and the sixth sacrificial patterning area 506 are sacrificial layer patterning areas of the first thin film bulk acoustic resonator 21, the second thin film bulk acoustic resonator 22, the third thin film bulk acoustic resonator 23, the fourth thin film bulk acoustic resonator 24, the fifth thin film bulk acoustic resonator 25 and the sixth thin film bulk acoustic resonator 26, respectively. The seventh sacrificial pattern region 507, the eighth sacrificial pattern region 508, the ninth sacrificial pattern region 509, the tenth sacrificial pattern region 510, and the eleventh sacrificial pattern region 511 are sacrificial layer pattern regions of the seventh thin film bulk acoustic resonator 31, the eighth thin film bulk acoustic resonator 32, the ninth thin film bulk acoustic resonator 33, the tenth thin film bulk acoustic resonator 34, and the eleventh thin film bulk acoustic resonator 35, respectively.
Wherein each resonator is provided with 5 sides, and the resonators are connected with each other through one side. And the horn-like portion from which each resonator extends is a release channel, each resonator may have a plurality of release channels, in this case 5 release channels per resonator. The released gas enters the release channel through the release hole, then enters the sacrificial layer to corrode the sacrificial layer material to become gas, and then is discharged through the release channel and the release hole.
Fig. 5 is a layout of the lower electrode layer, including a layout of the input terminal 11, the output terminal 12, and the ground terminal. The lower electrode layer includes a first lower electrode layout area 601, a second lower electrode layout area 602, a third lower electrode layout area 603, a fourth lower electrode layout area 604, a fifth lower electrode layout area 605, a sixth lower electrode layout area 606, a seventh lower electrode layout area 607, and an eighth lower electrode layout area 608. Wherein the first lower electrode layout area 601, the third lower electrode layout area 603, and the fifth lower electrode layout area 605 are connected to a ground terminal. The second lower electrode layout area 602 is connected to the input terminal 11, and the fourth lower electrode layout area 604 is connected to the output terminal 12.
The first lower electrode layout area 601 corresponds to the seventh thin film bulk acoustic resonator 31, the second lower electrode layout area 602 corresponds to the first thin film bulk acoustic resonator 21, the third lower electrode layout area 603 corresponds to the eleventh thin film bulk acoustic resonator 35, the fourth lower electrode layout area 604 corresponds to the sixth thin film bulk acoustic resonator 26, the fifth lower electrode layout area 605 corresponds to the tenth thin film bulk acoustic resonator 34, the sixth lower electrode layout area 606 corresponds to the second thin film bulk acoustic resonator 22 and the third thin film bulk acoustic resonator 23, the seventh lower electrode layout area 607 corresponds to the fourth thin film bulk acoustic resonator 24 and the fifth thin film bulk acoustic resonator 25, and the eighth lower electrode layout area 608 corresponds to the eighth thin film bulk acoustic resonator 32 and the ninth thin film bulk acoustic resonator 33.
Fig. 6 is a layout of the upper electrode layer, which includes a first upper electrode layout area 701, a second upper electrode layout area 702, a third upper electrode layout area 703 and a fourth upper electrode layout area 704. The first upper electrode layout area 701 corresponds to the first film bulk acoustic resonator 21, the second film bulk acoustic resonator 22 and the seventh film bulk acoustic resonator 31, the second upper electrode layout area 702 corresponds to the third film bulk acoustic resonator 23, the fourth film bulk acoustic resonator 24 and the eighth film bulk acoustic resonator 32, the third upper electrode layout area 703 corresponds to the fifth film bulk acoustic resonator 25, the sixth film bulk acoustic resonator 26 and the tenth film bulk acoustic resonator 34, and the fourth upper electrode layout area 704 corresponds to the ninth film bulk acoustic resonator 33 and the eleventh film bulk acoustic resonator 35.
Fig. 7 is a layout of a difference frequency layer, which includes a first difference frequency layout region 801 corresponding to the seventh thin film bulk acoustic resonator 31, a second difference frequency layout region 802 corresponding to the eighth thin film bulk acoustic resonator 32, a third difference frequency layout region 803 corresponding to the ninth thin film bulk acoustic resonator 33, and a fourth difference frequency layout region 804 corresponding to the tenth thin film bulk acoustic resonator 34.
Fig. 8 is a layout of an aperture layer that includes a plurality of release apertures, surrounding each resonator. One for each release hole. The released gas enters the release channel through the release hole, then enters the sacrificial layer area to corrode the sacrificial layer material to become gas, and then is discharged through the release channel and the release hole.
In this example, the air cavity type film bulk acoustic resonator filter of 3750MHz prepared as described above was tested, and the test results are shown in fig. 9. Curve 1 is the variation curve of S (2,1) with frequency (left vertical axis) of the air cavity type thin film bulk acoustic resonator filter. Curve 2 is the return loss (right vertical axis) of S (1,1) of the air cavity type thin film bulk acoustic resonator filter, and curve 3 is the return loss (right vertical axis) of S (2,2) of the air cavity type thin film bulk acoustic resonator filter. As can be seen from FIG. 9, the 1dB bandwidth is about 62MHz, and the suppression is 60dBc and 38dBc at 3650MHz and 3850MHz, respectively.
The embodiment of the utility model also provides a filter assembly which comprises the air cavity type film bulk acoustic resonator filter. All technical effects of the air cavity type film bulk acoustic resonator filter are achieved, and are not described herein again.
The above-mentioned parts in the embodiments may be freely combined or deleted to construct different embodiments, and the combined embodiments between the parts are not described herein again, but it is understood that different combined embodiments may be considered to be explicitly described in the specification after being explained herein, and can support different combined embodiments.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. An air cavity type film bulk acoustic resonator filter is characterized by comprising an input terminal, an output terminal, a plurality of film bulk acoustic resonators connected in series and a plurality of film bulk acoustic resonators connected in parallel;
the plurality of series thin film bulk acoustic resonators comprise a first thin film bulk acoustic resonator, a second thin film bulk acoustic resonator, a third thin film bulk acoustic resonator, a fourth thin film bulk acoustic resonator, a fifth thin film bulk acoustic resonator and a sixth thin film bulk acoustic resonator which are connected in series between the input terminal and the output terminal;
the plurality of film bulk acoustic resonators connected in parallel comprise a seventh film bulk acoustic resonator, an eighth film bulk acoustic resonator, a ninth film bulk acoustic resonator and a tenth film bulk acoustic resonator, one end of the seventh film bulk acoustic resonator is connected to a node between the first film bulk acoustic resonator and the second film bulk acoustic resonator, one end of the eighth film bulk acoustic resonator is connected to a node between the third film bulk acoustic resonator and the fourth film bulk acoustic resonator, one end of the ninth film bulk acoustic resonator is connected to the other end of the eighth film bulk acoustic resonator, and one end of the tenth film bulk acoustic resonator is connected to a node between the fifth film bulk acoustic resonator and the sixth film bulk acoustic resonator; and the other ends of the seventh film bulk acoustic resonator, the ninth film bulk acoustic resonator and the tenth film bulk acoustic resonator are respectively connected with a grounding terminal.
2. The air cavity type thin film bulk acoustic resonator filter according to claim 1, wherein a series resonance frequency and a parallel resonance frequency of the plurality of series thin film bulk acoustic resonators are the same; the series resonance frequency and the parallel resonance frequency of the plurality of film bulk acoustic resonators connected in parallel are the same.
3. The air cavity type thin film bulk acoustic resonator filter according to claim 1 or 2, wherein a series resonance frequency of the plurality of series thin film bulk acoustic resonators is the same as a parallel resonance frequency of the plurality of parallel thin film bulk acoustic resonators.
4. The air cavity type thin film bulk acoustic resonator filter of claim 1, wherein the first thin film bulk acoustic resonator has an area of 5950 μm2-6050μm2The areas of the second film bulk acoustic resonator and the third film bulk acoustic resonator are both 3450 μm2-3550μm2The areas of the fourth film bulk acoustic resonator, the fifth film bulk acoustic resonator and the tenth film bulk acoustic resonator are all 3350 μm2-3450μm2The area of the sixth film bulk acoustic resonator is 5250 mu m2-5350μm2The area of the seventh film bulk acoustic resonator is 8350 mu m2-8450μm2The area of the eighth film bulk acoustic resonator and the area of the ninth film bulk acoustic resonator are 3750 mu m2-3850μm2。
5. The air cavity type thin film bulk acoustic resonator filter according to claim 1, wherein a layout of the air cavity type thin film bulk acoustic resonator filter includes a sacrificial layer, a lower electrode layer, an upper electrode layer, a difference frequency layer, and an aperture layer, the difference frequency layer corresponds to the plurality of thin film bulk acoustic resonators connected in parallel, and the plurality of thin film bulk acoustic resonators connected in series do not have the difference frequency layer; the hole layer is provided with a plurality of release holes, each film bulk acoustic resonator is provided with a plurality of release channels, and each release channel at least corresponds to one release hole.
6. The air cavity type thin film bulk acoustic resonator filter according to claim 5, wherein the upper electrode layer has a thickness of
The thickness of the lower electrode layer is
The thickness of the difference frequency layer is
The diameter of the release hole is 15-25 μm, the air cavity type film bulk acoustic resonator filter further comprises a piezoelectric layer, and the thickness of the piezoelectric layer is
。
7. The air cavity type thin film bulk acoustic resonator filter according to claim 1, wherein the plurality of parallel thin film bulk acoustic resonators further includes an eleventh thin film bulk acoustic resonator, one end of the eleventh thin film bulk acoustic resonator is connected in series with the ninth thin film bulk acoustic resonator, and the other end of the eleventh thin film bulk acoustic resonator is connected to the ground terminal.
8. The air cavity type thin film bulk acoustic resonator filter according to claim 7, wherein the seventh thin film bulk acoustic resonator and the tenth thin film bulk acoustic resonator are each located on a first side of a straight line on which the input terminal and the output terminal are located, the eighth thin film bulk acoustic resonator, the ninth thin film bulk acoustic resonator, and the eleventh thin film bulk acoustic resonator are each located on a second side of the straight line, and the first side of the straight line is opposite to the second side of the straight line;
the center connecting lines of the first thin film bulk acoustic resonator, the second thin film bulk acoustic resonator and the third thin film bulk acoustic resonator form a first V shape, the center connecting lines of the third thin film bulk acoustic resonator, the fourth thin film bulk acoustic resonator and the fifth thin film bulk acoustic resonator form a second V shape, the center connecting lines of the fourth thin film bulk acoustic resonator, the fifth thin film bulk acoustic resonator and the sixth thin film bulk acoustic resonator form a third V shape, the opening angles of the first V shape and the third V shape are all larger than 90 degrees, the opening angle of the second V shape is smaller than 90 degrees, the opening directions of the first V shape and the third V shape are all towards the second side of the straight line, and the opening direction of the second V shape is towards the first side of the straight line;
the centers of the second thin film bulk acoustic resonator, the third thin film bulk acoustic resonator, and the fourth thin film bulk acoustic resonator are located on a straight line, and the centers of the first thin film bulk acoustic resonator and the sixth thin film bulk acoustic resonator are located on a straight line where the input terminal and the output terminal are located.
9. The air cavity type thin film bulk acoustic resonator filter according to claim 7, wherein a layout of the air cavity type thin film bulk acoustic resonator filter includes first to sixteenth layout areas;
the first layout area, the third layout area and the fifth layout area are grounding terminal layout areas, the second layout area is an input terminal layout area, the fourth layout area is an output terminal layout area, the third layout area is positioned at the upper part of the layout of the filter, and the first layout area, the fifth layout area, the second layout area and the fourth layout area are respectively and symmetrically arranged at two sides of the layout of the filter;
a sixth layout area, a seventh layout area, an eighth layout area, a ninth layout area, a tenth layout area, and a eleventh layout area are respectively layout areas of the first thin film bulk acoustic resonator, the second thin film bulk acoustic resonator, the third thin film bulk acoustic resonator, the fourth thin film bulk acoustic resonator, the fifth thin film bulk acoustic resonator, and the sixth thin film bulk acoustic resonator; the sixth layout area, the seventh layout area, the eighth layout area, the ninth layout area, the tenth layout area and the eleventh layout area are respectively connected in series between the second layout area and the fourth layout area;
a twelfth version area, a thirteenth version area, a fourteenth version area, a fifteenth version area and a sixteenth version area are respectively the layout areas of the seventh film bulk acoustic resonator, the eighth film bulk acoustic resonator, the ninth film bulk acoustic resonator, the tenth film bulk acoustic resonator and the eleventh film bulk acoustic resonator;
the twelfth layout area is positioned at the lower part of the sixth layout area, one end of the twelfth layout area is respectively connected with the sixth layout area and the seventh layout area, and the other end of the twelfth layout area is connected with the first layout area;
the thirteenth layout area is positioned at the upper part of the eighth layout area, one end of the thirteenth layout area is respectively connected with the eighth layout area and the ninth layout area, the other end of the thirteenth layout area is connected with one end of the fourteenth layout area, the other end of the fourteenth layout area is connected with one end of the sixteenth layout area, and the other end of the sixteenth layout area is connected with the third layout area;
the fifteenth layout area is positioned at the lower part of the eleventh layout area, one end of the fifteenth layout area is respectively connected with the tenth layout area and the eleventh layout area, and the other end of the fifteenth layout area is connected with the fifth layout area.
10. A filter assembly comprising the air cavity type thin film bulk acoustic resonator filter according to any one of claims 1 to 9.
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