CN114026786A - BAW resonator filter comprising band-stop resonators - Google Patents
BAW resonator filter comprising band-stop resonators Download PDFInfo
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- CN114026786A CN114026786A CN202080034291.XA CN202080034291A CN114026786A CN 114026786 A CN114026786 A CN 114026786A CN 202080034291 A CN202080034291 A CN 202080034291A CN 114026786 A CN114026786 A CN 114026786A
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Classifications
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- H—ELECTRICITY
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- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezo-electric or electrostrictive material
- H03H9/56—Monolithic crystal filters
- H03H9/566—Electric coupling means therefor
- H03H9/568—Electric coupling means therefor consisting of a ladder configuration
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
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- H03H9/1007—Mounting in enclosures for bulk acoustic wave [BAW] devices
- H03H9/105—Mounting in enclosures for bulk acoustic wave [BAW] devices the enclosure being defined by a cover cap mounted on an element forming part of the BAW device
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- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezo-electric or electrostrictive material
- H03H9/542—Filters comprising resonators of piezo-electric or electrostrictive material including passive elements
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
- H03H2003/021—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks the resonators or networks being of the air-gap type
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- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
- H03H2003/025—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks the resonators or networks comprising an acoustic mirror
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- H03—ELECTRONIC CIRCUITRY
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Abstract
The invention relates to a BAW resonator filter, which may comprise a BAW resonator bandpass filter ladder configurable to pass frequency components of a passband input signal received at an input node of the BAW resonator bandpass filter ladder to an output node of the BAW resonator bandpass filter ladder. A first series bandstop resonator may be coupled in series between the input port and the input node of the BAW resonator bandpass filter ladder, which may have a first anti-resonant frequency peak in a stop band below the pass band. A second series band-stop resonator may be coupled in series between the output port and the output node of the BAW resonator filter, the second series band-stop resonator may have a second anti-resonant frequency peak in the rejection band.
Description
Cross reference to related applications
The present application claims priority of U.S. provisional application serial No. 62/845,009 (attorney docket No. 181246 00009) entitled "WiFi 5GHz NEW ap roach FOR reversal impact", filed by US patent and trademark office at 8.8.8.2019, U.S. provisional application serial No. 62/885,047 (attorney docket No. 181246 00011) entitled "BULK access barrier filtration impact", filed by US patent and trademark office at 8.8.8.19.19.2018, part of U.S. provisional application serial No. 16/135,276 (attorney docket No. 969R 367. 5.2GHz WI-FI access barrier RF FILTER filed "attorney docket No. 3626 (attorney docket No. 367R 7), part of U.S. provisional application serial No. 368, filed by US patent and trademark # 2015.8.8.8.8.8, and part of US docket No. wo 5.7.7.7.7.7. the application serial No. docket No. wo 5.8. wo cited as" WiFi application serial No. 5.7 Please refer to a partial continuation application of U.S. patent application serial No. 15/784,919 (attorney docket No. 969R00007US2) filed on 16/10/2017 and entitled "piezo electric absorbent resin and PROCESS WITH piezo electric absorbent THIN FILM TRANSFER", which was a partial continuation application of U.S. patent application serial No. 15/068,510 filed on 11/3/2016.
This application incorporates for various purposes all of the following co-pending patent applications filed concurrently: U.S. patent application serial No. 14/298,057 (attorney docket No. a969RO-000100US), entitled "resonce circit WITH A SINGLE CRYSTAL CAPACITOR DIELECTRIC MATERIAL", filed 6/2014, has now been granted U.S. patent No. 9,673,384 on 6/2017; U.S. patent application Ser. No. 14/298,076 (attorney docket No. A969RO-000200US), entitled "METHOD OF MANUFACTURE FOR SINGLE CRYSTAL CAPACITOR DIELECTRIC FOR A RESONANCE CICUIT", filed 6.6.2014, now entitled U.S. patent No. 9,537,465 on 3.1.2017; U.S. patent application Ser. No. 14/298,100 (attorney docket No. A969RO-000300US), entitled "INTEGRATED CIRCUIT CONFIGURED WITH TWO OR MORE SINGLE CRYSTAL ACOUSTIC RESONATOR DEVICES", filed 6/2014, now assigned U.S. patent No. 9,571,061 on 14/2/2017; U.S. patent application serial No. 14/341,314 (attorney docket No. a969RO-000400US), entitled "WAFER SCALE PACKAGING," filed 6/2014, now entitled U.S. patent No. 9,805,966 by 31/10/2017; U.S. patent application Ser. No. 14/449,001 (attorney docket No. A969RO-000500US), entitled "MOBILE COMMUNICATION DEVICE CONFIRORRED WITH A SINGLE CRYSTAL PIEZO RESONATOR STRUCTURE", filed on 31.7.2014, now entitled U.S. patent No. 9,716,581 on 25.7.7.2017; U.S. patent application Ser. No. 14/469,503 (attorney docket No. A969RO-000600US), entitled "MEMBRANE SUBSTRATE STRUCTURE FOR SINGLE CRYSTAL ACOUSTIC RESONATOR DEVICE," filed on 26.8.2014, is now assigned U.S. patent No. 9,917,568 on 13.3.2018. The disclosures of all of the above applications and patents are hereby incorporated by reference.
Technical Field
The present invention generally relates to electronic devices. The present invention specifically provides related techniques of manufacturing methods and structures of a bulk acoustic wave resonator device, a single crystal filter, a resonator device, and the like. Merely by way of example, the present invention has been applied to single crystal resonator devices for communication devices, mobile devices, computing devices, and the like.
Background
Mobile telecommunications devices have been successfully deployed worldwide. Over 10 million mobile devices, including cellular telephones and smart phones, are produced each year with increasing unit production. Around 2012, with the rise of 4G/LTE and the explosive growth of mobile data traffic, the content of massive data is pushing the development of smart phone market, and is expected to reach 2B in the coming years. The coexistence of new and old standards and the desire for higher data rates are driving the radio frequency complexity in smart phones. Unfortunately, conventional rf technology still has problems that may lead to future drawbacks.
With the increasing prevalence of 4G LTE and 5G, wireless data communication requires high performance radio frequency filters at frequencies above about 5 GHz. Bulk Acoustic Wave Resonators (BAWRs) using crystalline piezoelectric thin films are the leading candidates to meet such requirements. The BAWR currently using a polycrystalline piezoelectric film is sufficient for a Bulk Acoustic Wave (BAW) filter having an operating frequency in the range of 1GHz to 3 GHz; however, when resonators and filters having an operating frequency of about 5GHz or more are required to have a thickness of 0.5 μm or less, the quality of the polycrystalline piezoelectric thin film is drastically deteriorated. Single crystal or epitaxial piezoelectric films grown on compatible crystal substrates exhibit good crystal quality and high piezoelectric properties, even up to ultra-thin thicknesses, such as 0.4 μm. Even so, the use and transfer of single crystal piezoelectric films in the manufacture of BAWR and BAW filters still presents challenges.
Disclosure of Invention
According to embodiments of the present invention, a BAW resonator filter including band-stop resonators may be provided. Based on these embodiments, in some embodiments according to the invention, a Bulk Acoustic Wave (BAW) resonator filter may include a BAW resonator bandpass filter circuit configured to pass frequency components of a passband input signal received at an input node of the BAW resonator bandpass filter circuit to an output node of the BAW resonator bandpass filter circuit. A first series bandstop resonator having a first anti-resonant frequency peak in a stop band below the pass band may be coupled in series between the input port and the input node of the BAW resonator bandpass filter ladder. A second series band-stop resonator having a second anti-resonant frequency peak in the rejection band may be coupled in series between the output port and the output node of the BAW resonator filter.
According to some embodiments of the invention, a Bulk Acoustic Wave (BAW) resonator filter may include a BAW resonator bandpass filter circuit configured to pass frequency components of a passband input signal received at an input port of the BAW resonator bandpass filter circuit to an output port of the BAW resonator bandpass filter circuit. A first parallel bandstop resonator may be coupled in parallel between the input port of the BAW resonator bandpass filter circuit and a reference node of the BAW resonator bandpass filter circuit, the first parallel bandstop resonator having a first resonant frequency peak in a bandstop band above the passband. A second parallel band-stop resonator may be coupled in parallel between the output port of the BAW resonator filter and the reference node, the second parallel band-stop resonator having a second resonant frequency peak in the rejection band.
In accordance with some embodiments of the invention, a Bulk Acoustic Wave (BAW) resonator filter may include a BAW resonator bandpass filter circuit configured to pass frequency components of a passband input signal received at an input node of the BAW resonator bandpass filter circuit to an output node of the BAW resonator bandpass filter circuit. A first series bandstop resonator may be coupled in series with the input port of the BAW resonator bandpass filter circuit or the output port of the BAW resonator bandpass filter circuit, the first series bandstop resonator having a first anti-resonant frequency peak in a stop band below the pass band.
According to some embodiments of the invention, a Bulk Acoustic Wave (BAW) resonator filter may include a BAW resonator bandpass filter circuit configured to pass frequency components of a passband input signal received at an input port of the BAW resonator bandpass filter circuit to an output port of the BAW resonator bandpass filter circuit. A first parallel band-stop resonator having a first resonant frequency peak in a stop band above a pass band may be coupled in parallel between the input port of the BAW resonator band-pass filter circuit and a reference node of the BAW resonator band-pass filter circuit or between the output port of the BAW resonator filter and the reference node.
According to some embodiments of the invention, a Bulk Acoustic Wave (BAW) resonator filter may include a first BAW resonator bandpass filter circuit configured to pass frequency components of a first passband input signal received at an input port of the first BAW resonator bandpass filter circuit to an output port of the first BAW resonator bandpass filter circuit. A first series bandstop resonator may be coupled in series with the input port of the BAW resonator bandpass filter circuit or the output port of the BAW resonator bandpass filter circuit, the first series bandstop resonator having a first anti-resonant frequency peak in a first stop band lower than the first pass band. The second BAW resonator bandpass filter circuit may be configured to pass frequency components of a second passband input signal received at the input port of the second BAW resonator bandpass filter circuit to the output port of the second BAW resonator bandpass filter circuit. The first parallel band-stop resonator may be coupled in parallel between the input port of the second BAW resonator band-pass filter circuit and a reference node of the second BAW resonator band-pass filter circuit or between the output port of the second BAW resonator filter and the reference node, the first parallel band-stop resonator having a first resonant frequency peak in a second stop band higher than the second pass band. The switch is configurable in a first state to couple an input signal to the first series bandstop resonator and in a second state to couple the input signal to the first parallel bandstop resonator.
Drawings
For a more complete understanding of the present invention, reference is now made to the accompanying drawings. Understanding that these drawings are not to be considered limiting of its scope, the presently described embodiments and the presently understood best mode of the invention are described in detail with reference to the accompanying drawings, wherein:
fig. 1A is a simplified diagram illustrating an acoustic wave resonator device having a top-side interconnect in accordance with an example of the present invention.
Fig. 1B is a simplified diagram illustrating an acoustic wave resonator device having bottom side interconnects in accordance with an example of the present invention.
Figure 1C is a simplified diagram illustrating an acoustic wave resonator device having interposer/uncapped structural interconnects in accordance with an example of the present invention.
Figure 1D is a simplified diagram illustrating an acoustic wave resonator device having an interposer/uncapped structural interconnect and a common backside trench, according to an example of the present invention.
Fig. 2 and 3 are simplified diagrams illustrating steps of a method of manufacturing an acoustic wave resonator device according to an example of the present invention.
Fig. 4A is a simplified diagram illustrating the method steps of creating a topside micro trench in accordance with an example of the present invention.
Fig. 4B and 4C are simplified diagrams illustrating an alternative method of performing the method steps of forming the topside micro trenches as described in fig. 4A.
Fig. 4D and 4E are simplified diagrams illustrating an alternative method of performing the method steps of forming the topside micro trenches as described in fig. 4A.
Fig. 5 to 8 are simplified diagrams illustrating steps of a method of manufacturing an acoustic wave resonator device according to an example of the present invention.
Fig. 9A is a simplified diagram illustrating method steps for forming backside trenches according to an example of the invention.
Fig. 9B and 9C are simplified diagrams illustrating an alternative method of performing the method steps of forming backside trenches as described in fig. 9A while singulating the seed substrate, in accordance with an embodiment of the present invention.
Figure 10 is a simplified diagram illustrating method steps for forming backside metallization and electrical interconnections between the top and bottom sides of a resonator in accordance with an example of the invention.
Fig. 11A and 11B are simplified diagrams illustrating alternative steps of a method of manufacturing an acoustic wave resonator device according to an example of the present invention.
Fig. 12A to 12E are simplified diagrams illustrating steps of a method of manufacturing an acoustic resonator device using a blind via interposer according to an example of the present invention.
Fig. 13 is a simplified diagram illustrating steps of a method of manufacturing an acoustic wave resonator device according to an example of the present invention.
Fig. 14A-14G are simplified diagrams illustrating method steps of a capping wafer process for an acoustic wave resonator device in accordance with an example of the present invention.
Fig. 15A-15E are simplified diagrams illustrating method steps for fabricating an acoustic resonator device having a common backside trench that can be implemented in both an interposer/cap version and a non-interposer version in accordance with an example of the present invention.
Fig. 16A to 16C to 31A to 31C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic wave resonator device according to an example of the present invention and method steps of the single crystal acoustic wave resonator device using a sacrificial layer transfer process.
Fig. 32A to 32C to 46A to 46C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device and method steps of a cavity bonding transfer process of the single-crystal acoustic wave resonator device according to an example of the present invention.
Fig. 47A to 47C to 59A to 59C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device and method steps of a solid-state assembly transfer process of the single-crystal acoustic wave resonator device according to an example of the present invention.
Fig. 60 is a simplified diagram illustrating filter passband requirements in the radio frequency spectrum according to an example of the present invention.
Figure 61 is a simplified diagram illustrating an overview of the key market for an acoustic rf filter application according to an example of the present invention.
Figure 62 is a simplified diagram illustrating the 5.2GHz radio frequency filter application domain in a tri-band Wi-Fi radio according to an example of the invention.
Fig. 63A to 63C are simplified cross-sectional views illustrating resonator devices according to various examples of the present invention.
Fig. 64A to 64C are simplified circuit diagrams showing representative lattice and ladder configurations of acoustic wave filter designs according to examples of the present invention.
Fig. 65A-65B are simplified diagrams illustrating packaging methods according to various examples of the invention.
FIG. 66 is a simplified diagram of a packaging method according to an example of the invention.
Fig. 67 is a simplified circuit diagram illustrating a 2-port BAW RF filter circuit according to an example of the present invention.
FIG. 68 is a profile of filter parameters according to an example of the invention.
Figure 69 is a simplified graph illustrating insertion loss as a function of frequency according to one example of the present invention.
Fig. 70-74 are simplified circuit block diagrams illustrating front end modules according to various examples of the invention.
Figure 75 is a schematic diagram of a BAW resonator filter including a BAW resonator bandpass filter ladder and first and second series band-stop resonators according to some embodiments of the invention.
Fig. 76 is a graph illustrating anti-resonant frequencies of a first series band-stop resonator and a second series band-stop resonator in the BAW resonator filter of fig. 75 in some embodiments of the invention.
Figure 77 is a schematic diagram of a BAW resonator filter including a BAW resonator bandpass filter ladder and first and second parallel band-stop resonators according to some embodiments of the invention.
Fig. 78 is a graph illustrating resonant frequencies of a first parallel band-stop resonator and a second parallel band-stop resonator in the BAW resonator filter of fig. 77 in some embodiments according to the invention.
Figure 79 is a schematic diagram of a combined BAW resonator filter controlled by a switch according to some embodiments of the invention, including a BAW resonator bandpass filter ladder having a first series bandstop resonator and a second series bandstop resonator and a BAW resonator bandpass filter ladder having a first parallel bandstop resonator and a second parallel bandstop resonator.
Fig. 80 is a schematic diagram of a BAW resonator filter including BAW resonator bandpass filter lattice points shown in fig. 64A including first and second series bandstop resonators in accordance with some embodiments of the present invention.
Figure 81 is a schematic diagram of a BAW resonator filter including BAW resonator bandpass filter lattice points shown in figure 64B including first and second series bandstop resonators in accordance with some embodiments of the present invention.
Fig. 82 is a graph representing a BAW resonator filter response including anti-resonant frequencies of the first series bandstop resonator and the second series bandstop resonator shown in fig. 80 and 81 in some embodiments according to the invention.
Fig. 83 is a schematic diagram of the BAW resonator filter of fig. 64A including BAW resonator bandpass filter lattice points including first parallel band-stop resonators and second parallel band-stop resonators, according to some embodiments of the invention.
Fig. 84 is a schematic diagram of a BAW resonator filter including BAW resonator bandpass filter lattice points shown in fig. 64B including first and second parallel band-stop resonators, according to some embodiments of the invention.
Fig. 85 is a graph illustrating a response of a BAW resonator filter including anti-resonant frequencies of the first parallel band-stop resonator and the second parallel band-stop resonator illustrated in fig. 83 and 84 in some embodiments of the invention.
Detailed Description
According to the present invention, electronic device related art is generally provided. The present invention specifically provides a method of manufacturing a bulk acoustic wave resonator device, a single crystal filter, a resonator device, and the like, and a related art of structure. Merely by way of example, the present invention has been applied to single crystal resonator devices for communication devices, mobile devices, computing devices, and the like.
Fig. 1A is a simplified diagram illustrating an acoustic wave resonator device 101 having a top-side interconnect according to an example of the present invention. As shown, the device 101 includes a thinned seed substrate 112 with an overlying single crystal piezoelectric layer 120 having a microvia 129. The microvia 129 may include a top-side micro-trench 121, a top-side metal plug 146, a backside trench 114, and a backside metal plug 147. Although device 101 is depicted as having a single micro-via 129, device 101 may have multiple micro-vias. A top side metal electrode 130 is formed overlying the piezoelectric layer 120. The top cap structure is bonded to the piezoelectric layer 120. The top cap structure includes interposer substrate 119 having one or more vias 151, the vias 151 connected to one or more top bond pads 143, one or more bond pads 144, and topside metal 145 with topside metal plugs 146. The solder balls 170 are electrically coupled to one or more top bond pads 143.
The thinned substrate 112 has a first backside trench 113 and a second backside trench 114. A backside metal electrode 131 is formed under a portion of the thinned seed substrate 112, the first backside trench 113, and the topside metal electrode 130. Backside metal plugs 147 are formed under thinned seed substrate 112, second backside trenches 114, and a portion of top-side metal 145. The backside metal plugs 147 are electrically coupled to the top side metal plugs 146 and the backside metal electrodes 131. Backside cap structure 161 is bonded to thinned seed substrate 112 under first backside trench 113 and second backside trench 114. Further details regarding the method of manufacturing the device are discussed below, beginning with fig. 2.
Fig. 1B is a simplified diagram illustrating an acoustic wave resonator device 102 having bottom side interconnects in accordance with an example of the present invention. As shown, the device 101 includes a thinned seed substrate 112 with an overlying piezoelectric layer 120 having micro-vias 129. The microvia 129 may include a top-side micro-trench 121, a top-side metal plug 146, a backside trench 114, and a backside metal plug 147. Although device 102 is depicted as having a single micro-via 129, device 102 may have multiple micro-vias. A top side metal electrode 130 is formed overlying the piezoelectric layer 120. The top cap structure is bonded to the piezoelectric layer 120. The top cap structure 119 includes bond pads that are connected to one or more bond pads 144 on the piezoelectric layer 120 and topside metal 145. Top side metal 145 includes top side metal plugs 146.
The thinned substrate 112 has a first backside trench 113 and a second backside trench 114. A backside metal electrode 131 is formed under a portion of the thinned seed substrate 112, the first backside trench 113, and the topside metal electrode 130. Backside metal plugs 147 are formed under thinned seed substrate 112, second backside trenches 114, and a portion of top side metal plugs 146. The backside metal plugs 147 are electrically coupled to the top side metal plugs 146. Backside cap structure 162 is bonded to thinned seed substrate 112 under the first and second backside trenches. One or more backside bond pads 171, 172, 173 are formed within one or more portions of the backside cap structure 162. The solder balls 170 are electrically coupled to one or more backside bond pads 171 and 173. Further details regarding the method of manufacturing the device are discussed below beginning with fig. 14A.
Figure 1C is a simplified diagram illustrating an acoustic wave resonator device having interposer/uncapped structural interconnects in accordance with an example of the present invention. As shown, the device 103 includes a thinned seed substrate 112 with an overlying single crystal piezoelectric layer 120 having micro-vias 129. The microvia 129 may include a top-side micro-trench 121, a top-side metal plug 146, a backside trench 114, and a backside metal plug 147. Although device 103 is depicted as having a single micro-via 129, device 103 may have multiple micro-vias. A top side metal electrode 130 is formed overlying the piezoelectric layer 120. The thinned substrate 112 has a first backside trench 113 and a second backside trench 114. A backside metal electrode 131 is formed under a portion of the thinned seed substrate 112, the first backside trench 113, and the topside metal electrode 130. Backside metal plugs 147 are formed under thinned seed substrate 112, second backside trenches 114, and a portion of top-side metal 145. The backside metal plugs 147 are electrically coupled to the top side metal plugs 146 and the backside metal electrodes 131. Further details regarding the method of manufacturing the device are discussed below, beginning with fig. 2.
Figure 1D is a simplified diagram illustrating an acoustic wave resonator device having an interposer/uncapped structural interconnect and a common backside trench, according to an example of the present invention. As shown, the device 104 includes a thinned seed substrate 112 with an overlying single crystal piezoelectric layer 120 having microvias 129. The microvia 129 may include a top-side microvia 121, a top-side metal plug 146, and a backside metal 147. Although device 104 is depicted as having a single micro-via 129, device 104 may have multiple micro-vias. A top side metal electrode 130 is formed overlying the piezoelectric layer 120. The thinned substrate 112 has a first backside trench 113. A backside metal electrode 131 is formed under a portion of the thinned seed substrate 112, the first backside trench 113, and the topside metal electrode 130. A backside metal 147 is formed under a portion of the thinned seed substrate 112, the second backside trench 114, and the topside metal 145. The backside metal 147 is electrically coupled to the topside metal plug 146 and the backside metal electrode 131. Further details regarding the method of manufacturing the device are discussed below, beginning with fig. 2.
Fig. 2 and 3 are simplified diagrams illustrating steps of a method of manufacturing an acoustic wave resonator device according to an example of the present invention. The method illustrates a process for fabricating an acoustic wave resonator device similar to that shown in figure 1A. Figure 2 may represent method steps for providing a partially processed piezoelectric substrate. As shown, device 102 includes a seed substrate 110 having a piezoelectric layer 120 formed thereover. In a specific example, the seed substrate may comprise silicon, silicon carbide, aluminum oxide, or a single crystal aluminum gallium nitride material, among others. Piezoelectric layer 120 can comprise a piezoelectric single crystal layer or a thin film piezoelectric single crystal layer.
Fig. 3 may represent method steps for forming a top side metallization or top resonator metal electrode 130. In a particular example, the top-side metal electrode 130 can include molybdenum, aluminum, ruthenium, or titanium materials, and the like, as well as combinations thereof. This layer may be deposited and patterned on top of the piezoelectric layer by a lift-off process, a wet etching process, a dry etching process, a metal printing process, a metal lamination process, etc. The lift-off process may include a sequential process of lithographic patterning, metal deposition, and lift-off steps to produce the top-side metal layer. The wet/dry etch process may include a sequential process of metal deposition, photolithographic patterning, metal deposition, and metal etch steps to produce the top-side metal layer. One of ordinary skill in the art would recognize other variations, modifications, and alternatives.
Fig. 4A is a simplified diagram illustrating steps of a method of manufacturing an acoustic wave resonator device 401 according to an example of the present invention. This figure may represent method steps for forming one or more top-side micro-trenches 121 within a portion of the piezoelectric layer 120. The top-side micro-groove 121 may serve as the primary interconnection node between the top and bottom sides of the acoustic membrane, which will be improved in subsequent method steps. In one example, the topside micro trenches 121 extend all the way through the piezoelectric layer 120 and stop in the seed substrate 110. The topside micro-trench 121 may be formed by a dry etching process, a laser drilling process, or the like. Fig. 4B and 4C detail these options.
Fig. 4B and 4C are simplified diagrams illustrating an alternative method of performing the method steps as described in fig. 4A. As shown, fig. 4B illustrates the method steps of using laser drilling, which can quickly and accurately form the top-side micro-groove 121 in the piezoelectric layer 120. In one example, laser drilling can be used to form a nominal 50 μm hole or a 10 μm to 500 μm diameter hole through the piezoelectric layer 120 and stopping in the seed substrate 110 at the interface between layers 120 and 110. A protective layer 122 may be formed overlying the piezoelectric layer 120 and the top-side metal electrode 130. This protective layer 122 may be used to protect the device from laser debris and to provide a mask for etching the top-side micro-vias 121. In a specific example, the laser drill may be an 11W high power diode pumped UV laser or the like. Other steps may follow the removal of the mask 122. The mask may also be omitted during laser drilling and air flow may be used to remove laser debris.
Fig. 4C may represent a method step of forming a top-side micro-trench 121 in the piezoelectric layer 120 using a dry etching process. As shown, a photolithographic masking layer 123 may be formed overlying the piezoelectric layer 120 and the top-side metal electrode 130. The topside micro-groove 121 may be formed by exposure to a plasma.
Fig. 4D and 4E are simplified diagrams illustrating an alternative method of performing the method steps as described in fig. 4A. These figures may represent method steps for fabricating multiple acoustic wave resonator devices simultaneously. In fig. 4D, two devices are shown on Die # 1 and Die # 2, respectively. Fig. 4E shows the process of forming micro vias 121 on each of these dies (Die) while also etching scribe lines 124 or scribe lines. In one example, etching scribe line 124 separates and releases the stress in piezoelectric single crystal layer 120.
Fig. 5 to 8 are simplified diagrams illustrating steps of a method of manufacturing an acoustic wave resonator device according to an example of the present invention. Fig. 5 may represent method steps for forming one or more bond pads 140 and forming a topside metal 141 electrically coupled to at least one bond pad 140. Topside metal 141 may include topside metal plug 146 formed within topside micro trench 121. In a specific example, top side metal plug 146 fills top side micro-trench 121 to form a top side portion of the micro-via.
In an example, the bond pads 140 and topside metal 141 may comprise gold material or other interconnect metal material, depending on the application of the device. These metal materials may be formed through a peeling process, a wet etching process, a dry etching process, a screen printing process, an electroplating process, a metal printing process, and the like. In one specific example, the deposited metal material may also be used as a pad for a capping structure, as will be described below.
Fig. 6 may represent method steps for preparing an acoustic resonator device to be bonded, which may be a hermetic bond. As shown, the top cap structure is positioned over the partially processed acoustic resonator device, as described in the previous figures. The top cap structure may be formed using two configurations of the interposer substrate 119: a fully processed interposer version 601 (through glass vias) and a partially processed interposer version 602 (blind vias version). In version 601, the interposer substrate 119 includes via structures 151 that extend through the interposer substrate 119 and are electrically coupled to the bottom bond pads 142 and the top bond pads 143. In the version 602, the interposer substrate 119 includes blind via structures 152 that extend from the bottom side through only a portion of the interposer substrate 119. These blind via structures 152 are also electrically coupled to the bottom bond pads 142. In a particular example, the interposer substrate may comprise silicon, glass, smart glass, or other similar materials.
Fig. 7 may represent method steps for bonding a top cap structure to a partially processed acoustic wave resonator device. As shown, the interposer substrate 119 is bonded to the piezoelectric layer by bond pads 140, 142 and topside metal 141, which are labeled bond pads 144 and topside metal 145. The bonding process may be accomplished using a crimping method or the like. Fig. 8 may represent a method step of thinning the seed substrate 110, which is time stamped to thin the seed substrate 111. The substrate thinning process may include a grinding process and an etching process, etc. In a specific example, the process may include a wafer backgrinding process followed by stress relief, which may involve a dry etch, CMP polishing, or an annealing process.
Fig. 9A is a simplified diagram illustrating steps of a method of manufacturing an acoustic wave resonator device 901 according to an example of the present invention. Fig. 9A may represent method steps of forming backside trenches 113 and 114 to allow access to the piezoelectric layer from the backside of the thinned seed substrate 111. In an example, the first backside trench 113 may be formed within the thinned seed substrate 111 and below the topside metal electrode 130. A second backside trench 114 may be formed within the thinned seed substrate 111 and under the top-side micro-trench 121 and the top-side metal plug 146. The substrate is shown thinned substrate 112 at this time. In a specific example, these trenches 113 and 114 may be formed using a Deep Reactive Ion Etching (DRIE) process, a Bosch process, or the like. The size, shape and number of trenches may vary with the design of the acoustic wave resonator device. In various examples, the first backside trench may be formed with a trench shape similar to a topside metal electrode shape or a backside metal electrode shape. The first backside trench may also be formed with a trench shape different from the topside metal electrode shape and the backside metal electrode shape.
Fig. 9B and 9C are simplified diagrams illustrating an alternative method of performing the method steps as described in fig. 9A. Similar to fig. 4D and 4E, these figures may represent method steps for simultaneously fabricating a plurality of acoustic wave resonator devices. In fig. 9B, two devices having a cap structure are shown on Die # 1 and Die # 2, respectively. Fig. 9C shows the process of forming backside trenches 113, 114 on each of these dies while also etching scribe lines 115 or scribe lines. In one example, etching scribe lines 115 provides an alternative way to singulate the backside wafer 112.
Fig. 10 is a simplified diagram illustrating steps of a method of fabricating an acoustic wave resonator device 1000 in accordance with an example of the present invention. This figure may represent the method steps of forming backside metal electrode 131 and backside metal plug 147 within the backside trench of thinned seed substrate 112. In an example, backside metal electrode 131 can be formed under one or more portions of thinned substrate 112, within first backside trench 113, and under topside metal electrode 130. This process completes the resonator structure within the acoustic wave resonator device. Backside metal plugs 147 may be formed under one or more portions of thinned substrate 112, within second backside trenches 114, and under top-side micro-trenches 121. The backside metal plugs 147 may be electrically coupled to the backside metal plugs 146 and the backside metal electrodes 131. In a specific example, the backside metal electrode 130 can include molybdenum, aluminum, ruthenium, or titanium materials, and the like, as well as combinations thereof. The backside metal plug may comprise gold material, low resistance interconnect metal, electrode metal, and the like. These layers may be deposited using the deposition methods described previously.
Fig. 11A and 11B are simplified diagrams illustrating alternative steps of a method of manufacturing an acoustic wave resonator device according to an example of the present invention. These figures show the method of bonding the backside cap structure under the thinned seed substrate 112. In fig. 11A, the backside cap structure is a dry film cap 161, which may comprise a permanent photo-induced dry film, such as solder resist, polyimide, or the like. Bonding such a cap structure is economical and reliable, but may not result in a hermetic seal. In fig. 11B, the backside cap structure is a substrate 162, which may comprise silicon, glass, or other similar material. Bonding such substrates may provide a hermetic seal, but may be more costly and require additional processes. Depending on the application, any of these backside cap structures may be bonded under the first backside via and the second backside via.
Fig. 12A to 12E are simplified diagrams illustrating steps of a method of manufacturing an acoustic wave resonator device according to an example of the present invention. More specifically, these figures describe additional steps to process the blind via interposer "602" version of the top cap structure. Fig. 12A shows an acoustic wave resonator device 1201 having a blind via 152 in the top cap structure. In fig. 12B, interposer substrate 119 is thinned, which forms thinned interposer substrate 118 to expose blind vias 152. The thinning process may be a combination of a grinding process and an etching process as described for thinning of the seed substrate. In fig. 12C, a redistribution layer (RDL) process and a metallization process may be applied to create a top cap bond pad 160 formed overlying the blind via 152 and electrically coupled to the blind via 152. As shown in fig. 12D, a Ball Grid Array (BGA) process may be applied to form solder balls 170 overlying and electrically coupled to the top cap bond pads 160. As shown in fig. 12E, this process prepares the acoustic resonator device for wire bonding 171.
Fig. 13 is a simplified diagram illustrating steps of a method of manufacturing an acoustic wave resonator device according to an example of the present invention. As shown, device 1300 includes two fully processed acoustic resonator devices that are ready to be singulated to create separate devices. In an example, the die singulation process can be accomplished using a wafer sawing process, a laser cutting singulation process, or other processes and combinations thereof.
Fig. 14A to 14G are simplified diagrams illustrating steps of a method of manufacturing an acoustic wave resonator device according to an example of the present invention. The method illustrates the process of making an acoustic wave resonator device similar to that shown in figure 1B. The method of this acoustic resonator example may undergo steps similar to those described in fig. 1-5. Fig. 14A shows the difference between this method and the previous method. Here, the top cap structure substrate 119 includes only one layer of metallization with one or more bottom bond pads 142. Compared to fig. 6, the top cap structure has no via structure therein because the interconnects will be formed on the bottom side of the acoustic wave resonator device.
Fig. 14B-14F depict method steps similar to those described in the first process flow. Fig. 14B may represent method steps for bonding a top cap structure to the piezoelectric layer 120 through the bond pads 140, 142 and topside metal 141, which are labeled bond pads 144 and topside metal 145 and topside metal plugs 146. Fig. 14C may represent a method step of thinning the seed substrate 110, which forms a thinned seed substrate 111, similar to that described in fig. 8. Fig. 14D may represent a method step of forming a first backside trench and a second backside trench, similar to that described in fig. 9A. Fig. 14E may represent method steps for forming backside metal electrode 131 and backside metal plug 147, similar to the steps described in fig. 10. Fig. 14F may represent a method step of bonding the backside cap structure 162, similar to that described in fig. 11A and 11B.
Fig. 14G shows another step different from the aforementioned process flow. Here, the backside bond pads 171, 172, and 173 are formed within the backside cap structure 162. In one example, these backside bond pads 171 and 173 can be formed by masking processes, etching processes, and metal deposition processes similar to those used to form other metal materials. A BGA process may be applied to form solder balls 170 in contact with these backside bond pads 171 and 173, thus preparing the acoustic resonator device 1407 for wire bonding.
Fig. 15A to 15E are simplified diagrams illustrating steps of a method of manufacturing an acoustic wave resonator device according to an example of the present invention. The method illustrates the process of making an acoustic wave resonator device similar to that shown in figure 1B. This example method may undergo steps similar to those described in fig. 1-5. Fig. 15A shows the difference between this method and the previous method. A temporary carrier 218 with a temporary adhesive layer 217 is attached to the substrate. In a particular example, the temporary carrier 218 may comprise a glass wafer, a silicon wafer, or other wafer, and the like.
Fig. 15B-15F depict method steps similar to those described in the first process flow. Fig. 15B may represent a method step of thinning the seed substrate 110, which forms a thinned substrate 111, similar to that described in fig. 8. In a specific example, thinning the seed substrate 110 may include a back grinding process followed by a stress relief process. The stress relief process may include a dry etch, Chemical Mechanical Planarization (CMP), and an anneal process.
Fig. 15C may represent a method step of forming the common backside trench 113, similar to the technique described in fig. 9A. The main difference is that a common backside trench is disposed under top-side metal electrode 130, top-side micro-trench 121, and top-side metal plug 146. In an example, the common backside trench 113 is a backside resonant cavity that can vary in size, shape (all possible geometries), and sidewall profile (tapered convex, tapered concave, or right angle). In a specific example, forming the common backside trench 113 may include a photolithography process, which may include front-to-back alignment and dry etching of the backside substrate 111. The piezoelectric layer 120 can serve as an etch stop layer for forming the common backside trench 113.
Fig. 15D may represent the method steps for forming the backside metal electrode 131 and the backside metal 147, similar to the steps described in fig. 10. In an example, forming the backside metal electrode 131 can include depositing and patterning a metal material within the common backside trench 113. Here, the backside metal 131 serves as an electrode, and the backside plug/connection metal 147 is located within the micro via 121. The thickness, shape and type of metal may vary with resonator/filter design. For example, the backside electrode 131 and the via plug metal 147 may be different metals. In a specific example, these backside metals 131, 147 can be deposited and patterned on the surface of the piezoelectric layer 120, or redistributed to the backside of the substrate 112. In one example, the backside metal electrode can be patterned to be disposed within the boundaries of the common backside trench such that the backside metal electrode does not contact one or more sidewalls of the seed substrate created during the formation of the common backside trench.
Fig. 15E may represent a method step similar to that described for bonding the backside cap structure 162 of fig. 11A and 11B, followed by debonding of the temporary carrier 218 and cleaning of the device top side to remove the temporary adhesive 217. One of ordinary skill in the art will recognize other variations, modifications, and alternatives to the foregoing method steps.
As used herein, the term "substrate" may refer to a bulk substrate or may include overlying growth structures, such as aluminum, gallium, or aluminum gallium nitride ternary compounds, including epitaxial or functional regions, combinations thereof, and the like.
One or more advantages over the prior art are achieved with the present invention. In particular, one of ordinary skill in the art can manufacture the present devices in a relatively simple and cost-effective manner while using conventional materials and/or methods. With the present method, a reliable single crystal-based acoustic wave resonator can be created using a variety of three-dimensional stacking approaches by wafer-level processes. Such filters or resonators may be implemented in RF filter devices, RF filter systems, and the like. One or more of these advantages may be achieved according to embodiments. There may of course be other variations, modifications, and alternatives.
With the increasing prevalence of 4G LTE and 5G, wireless data communication requires high performance radio frequency filters at frequencies above about 5 GHz. Bulk Acoustic Wave Resonators (BAWRs) are widely used in such filters operating at frequencies below about 3GHz and are the leading candidates for meeting such requirements. The current bulk acoustic wave resonator uses a polycrystalline piezoelectric AIN film in which the c-axis of each crystal grain is aligned perpendicular to the film surface to achieve high piezoelectric performance, and the a-axis or b-axis of the crystal grain is randomly distributed. This particular grain distribution works well when the thickness of the piezoelectric film is about 1 μm or more, which is a perfect thickness for Bulk Acoustic Wave (BAW) filters in the operating frequency range of 1GHz to 3 GHz. However, when the thickness necessary for resonators and filters having an operating frequency of 5GHz or more is reduced to about 0.5 μm or less, the quality of the polycrystalline piezoelectric film is drastically deteriorated.
Single crystal or epitaxial piezoelectric films grown on compatible crystal substrates exhibit good crystal quality and high piezoelectric properties, even up to ultra-thin thicknesses, such as 0.4 μm. The present invention provides a fabrication process and structure for high quality bulk acoustic wave resonators with single crystal or epitaxial piezoelectric films for high frequency BAW filter applications.
BAWR requires a piezoelectric material in a crystalline form, such as AlN, i.e., polycrystalline or single crystal. The film quality is heavily dependent on the chemical, crystalline or morphological quality of the film growth layer. In conventional BAWR processes, including thin Film Bulk Acoustic Resonator (FBAR) or solid state assembled resonator (SMR) geometries, a piezoelectric film is grown on a patterned bottom electrode, typically made of molybdenum (Mo), tungsten (W), or ruthenium (Ru). The surface geometry of the patterned bottom electrode can significantly affect the crystal orientation and crystal quality of the piezoelectric film, requiring complex modifications to the structure.
Thus, the present invention uses a single crystal piezoelectric film and a thin film transfer process to produce a BAWR that enhances the final quality factor and the electromechanical coupling of the RF filter. Such methods and structures facilitate the fabrication of RF filters using single crystal or epitaxial piezoelectric films to meet the growing demands of contemporary data communications.
In one example, the present invention provides a transfer structure and process for an acoustic wave resonator device that provides a flat high quality single crystal piezoelectric film for excellent acoustic wave control and high frequency high Q. As described above, the polycrystalline piezoelectric layer limits Q at high frequencies. Furthermore, growing an epitaxial piezoelectric layer on a patterned electrode can affect the crystal orientation of the piezoelectric layer, which limits the ability to tightly bound the resulting resonator. As also described below, embodiments of the present invention may overcome these limitations, exhibiting improved performance and cost-effectiveness.
Fig. 16A to 16C to 31A to 31C illustrate a method of manufacturing an acoustic wave resonator device using a sacrificial layer transfer structure. In the series of figures described below, the "a" diagram shows a simplified top-down cross-sectional view illustrating a single crystal resonator device according to various embodiments of the present invention. The "B" diagram shows a simplified diagram illustrating a longitudinal cross-section of the same device in the "a" diagram. Similarly, the "C" diagram shows a simplified lateral cross-sectional diagram illustrating the same device in the "a" diagram. In some instances, certain features are omitted to highlight other features and relationships between such features. Those of ordinary skill in the art will appreciate that variations, modifications, and alternatives to the examples shown in the series of figures may be made.
Fig. 16A to 16C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of the single crystal acoustic resonator device using a sacrificial layer transfer process according to an example of the present invention. As shown, these figures illustrate the method steps for forming a piezoelectric film 1620 overlying a growth substrate 1610. In an example, growth substrate 1610 may include silicon (S), silicon carbide (SiC), or other similar materials. The piezoelectric film 1620 may be an epitaxial film including aluminum nitride (AlN), gallium nitride (GaN), or other similar materials. Additionally, the piezoelectric substrate may be subjected to thickness trimming.
Fig. 17A to 17C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of the single crystal acoustic resonator device using a sacrificial layer transfer process according to an example of the present invention. As shown, these figures illustrate the method steps for forming a first electrode 1710 overlying a surface region of a piezoelectric film 1620. In an example, the first electrode 1710 can include molybdenum (Mo), ruthenium (Ru), tungsten (W), or other similar materials. In a specific example, the first electrode 1710 may be subjected to a slope of dry etching. For example, the slope may be about 60 degrees.
Fig. 18A to 18C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of the single crystal acoustic resonator device using a sacrificial layer transfer process according to an example of the present invention. As shown, these figures illustrate the method steps for forming a first passivation layer 1810 overlying the first electrode 1710 and the piezoelectric film 1620. In an example, the first passivation layer 1810 may include silicon nitride (SiN), silicon oxide (SiO)x) Or other similar material. In a specific example, the first passivation layer 1810 may have a thickness ranging from about 50nm to about 100 nm.
Fig. 19A to 19C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of the single crystal acoustic resonator device using a sacrificial layer transfer process according to an example of the present invention. As shown, these figures illustrate a portion formed overlying a first electrode 1810Method steps of separating sacrificial layer 1910 over a portion of piezoelectric film 1620. In an example, the sacrificial layer 1910 can include polysilicon (poly-Si), amorphous silicon (a-Si), or other similar materials. In a specific example, the sacrificial layer 1910 may be subjected to a tapered dry etch and deposited to a thickness of about 1 μm. In addition, phosphorus-doped SiO2(PSG) can be used with different support layer combinations (e.g., SiN)x) The sacrificial layer of (a).
Fig. 20A to 20C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of the single crystal acoustic resonator device using a sacrificial layer transfer process according to an example of the present invention. As shown, these figures illustrate the method steps of forming a support layer 2010 overlying sacrificial layer 1910, first electrode 1710 and piezoelectric film 1620. In one example, the support layer 2010 may comprise silicon dioxide (SiO)2) Silicon nitride (SiN), or other similar materials. In a specific example, the support layer 2010 may be deposited at a thickness of about 2-3 μm. As described above, in the case of a PSG sacrificial layer, other support layers (e.g., SiN) may be usedx)。
Fig. 21A to 21C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of the single crystal acoustic resonator device using a sacrificial layer transfer process according to an example of the present invention. As shown, these figures illustrate method steps of polishing the support layer 2010 to form a polishing support layer 2011. In one example, the polishing process may include a chemical mechanical planarization process or the like.
Fig. 22A to 22C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of the single crystal acoustic resonator device using a sacrificial layer transfer process according to an example of the present invention. As shown, these figures illustrate a support layer 2011 over the flip device and the physically coupled overlying bond substrate 2210. In an example, the bonded substrate 2210 may include a silicon (Si), sapphire (Al) overlay2O3) Silicon dioxide (SiO)2) A bonding support layer 2220 (SiO) over a substrate of silicon carbide (SiC) or other similar material2Or similar material). In one embodiment, the bonding support of the bonded substrate 2210Layer 2220 is physically coupled to polishing support layer 2011. Additionally, the physical coupling process may include a room temperature bonding process followed by an annealing process at 300 degrees celsius.
Fig. 23A to 23C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of the single crystal acoustic resonator device using a sacrificial layer transfer process according to an example of the present invention. As shown, these figures illustrate method steps for removing the growth substrate 1610 or otherwise transferring the piezoelectric film 1620. In an example, the removal process may include a grinding process, a blanket etching process, a thin film transfer process, an ion implantation transfer process, a laser crack transfer process, and the like, and combinations thereof.
Fig. 24A to 24C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of the single crystal acoustic resonator device using a sacrificial layer transfer process according to an example of the present invention. As shown, these figures illustrate method step 1810 of forming an electrode contact via 2410 in a piezoelectric film 1620 (referred to as piezoelectric film 1621) overlying a first electrode 1710 and forming one or more release holes 2420 in the piezoelectric film 1620 and a first passivation layer overlying a sacrificial layer 1910. The via formation process may include various types of etching processes.
Fig. 25A to 25C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of the single crystal acoustic resonator device using a sacrificial layer transfer process according to an example of the present invention. As shown, these figures illustrate the method steps of forming a second electrode 2510 overlying a piezoelectric film 1621. In one example, forming the second electrode 2510 includes depositing molybdenum (Mo), ruthenium (Ru), tungsten (W), or other similar materials; the second electrode 2510 is then etched to form an electrode cavity 2511 and portions 2511 are removed from the second electrode to form a top metal 2520. In addition, the top metal 2520 is physically coupled to the first electrode 1720 through an electrode contact via 2410.
Fig. 26A to 26C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of the single crystal acoustic resonator device using a sacrificial layer transfer process according to an example of the present invention. As shown, these figures illustrate the method steps of forming a first contact metal 2610 overlying a portion of the second electrode 2510 and a portion of the piezoelectric film 1621 and forming a second contact metal 2611 overlying a portion of the top metal 2520 and a portion of the piezoelectric film 1621. In an example, the first contact metal and the second contact metal may include gold (Au), aluminum (Al), copper (Cu), nickel (Ni), aluminum copper (AlCu), or a related alloy of these or other similar materials.
Fig. 27A to 27C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of the single crystal acoustic resonator device using a sacrificial layer transfer process according to an example of the present invention. As shown, these figures illustrate the method steps of forming a second passivation layer 2710 overlying the second electrode 2510, the top metal 2520 and the piezoelectric film 1621. In an example, the second passivation layer 2710 may include silicon nitride (SiN), silicon oxide (SiO)x) Or other similar material. In a specific example, the second passivation layer 2710 may have a thickness ranging from about 50nm to about 100 nm.
Fig. 28A to 28C are simplified diagrams showing various cross-sectional views of a single-crystal acoustic wave resonator device according to an example of the present invention and method steps of the single-crystal acoustic wave resonator device using a sacrificial layer transfer process. As shown, these figures illustrate the method steps of removing the sacrificial layer 1910 to form the air cavity 2810. In an example, the removal process may include a polysilicon etch or an amorphous silicon etch, or the like.
Fig. 29A to 29C are simplified diagrams showing various cross-sectional views of a single crystal acoustic resonator device according to another example of the present invention and method steps of the single crystal acoustic resonator device using a sacrificial layer transfer process. As shown, these figures illustrate the method steps of processing the second electrode 2510 and the top metal 2520 to form a processed second electrode 2910 and a processed top metal 2920. This step may follow the formation of the second electrode 2510 and the top metal 2520. In one example, the processing of the two components includes depositing molybdenum (Mo), ruthenium (Ru), tungsten (W), or other similar materials; the material is then etched (e.g., dry etched, etc.) to form the processed second electrode 2910 and the electrode cavity 2912 and the processed top metal 2920. By removing the portion 2911, the treated top metal 2920 remains separated from the treated second electrode 2910. In a particular example, the treated second electrode 2910 is characterized by the addition of an energy-constraining structure on the treated second electrode 2910 to increase Q.
Fig. 30A to 30C are simplified diagrams showing various cross-sectional views of a single-crystal acoustic wave resonator device according to another example of the present invention and method steps of the single-crystal acoustic wave resonator device using a sacrificial layer transfer process. As shown, these figures illustrate method steps for processing the first electrode 1710 to form a processed first electrode 2310. This step may follow the formation of the first electrode 1710. In one example, the processing of the two components includes depositing molybdenum (Mo), ruthenium (Ru), tungsten (W), or other similar materials; the material is then etched (e.g., dry etched, etc.) to form the processed first electrode 3010 and an electrode cavity, similar to the processed second electrode 2910. Air cavity 2811 shows the change in cavity shape due to the treated first electrode 3010. In a specific example, the processed first electrode 3010 is characterized by adding an energy-constraining structure on the processed first electrode 3010 to increase Q.
Fig. 31A to 31C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of the single crystal acoustic resonator device using a sacrificial layer transfer process according to another example of the present invention. As shown, these figures illustrate the method steps of processing the first electrode 1710 to form a processed first electrode 2310 and processing the second electrode 2510/top metal 2520 to form a processed second electrode 2910/processed top metal 2920. These steps may follow the formation of each respective electrode, as described in fig. 29A-29C and fig. 30A-30C. One of ordinary skill in the art would recognize other variations, modifications, and alternatives.
Fig. 32A to 32C to 46A to 46C illustrate a method of manufacturing an acoustic wave resonator device using a non-sacrificial layer transfer structure. In the series of figures described below, the "a" diagram shows a simplified top-down cross-sectional view illustrating a single crystal resonator device according to various embodiments of the present invention. The "B" diagram shows a simplified diagram illustrating a longitudinal cross-section of the same device in the "a" diagram. Similarly, the "C" diagram shows a simplified lateral cross-sectional diagram illustrating the same device in the "a" diagram. In some instances, certain features are omitted to highlight other features and relationships between such features. Those of ordinary skill in the art will appreciate that variations, modifications, and alternatives to the examples shown in the series of figures may be made.
Fig. 32A to 32C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device and method steps of a transfer process of the single-crystal acoustic wave resonator device according to an example of the present invention. As shown, these figures illustrate the method steps of forming a piezoelectric film 3220 overlying a growth substrate 3210. In an example, growth substrate 3210 may include silicon (S), silicon carbide (SiC), or other similar materials. The piezoelectric film 3220 may be an epitaxial film including aluminum nitride (AlN), gallium nitride (GaN), or other similar materials. Additionally, the piezoelectric substrate may be subjected to thickness trimming.
Fig. 33A to 33C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of a transfer process of the single crystal acoustic resonator device according to an example of the present invention. As shown, these figures illustrate the method steps of forming a first electrode 3310 overlying the surface region of the piezoelectric film 3220. In an example, the first electrode 3310 may include molybdenum (Mo), ruthenium (Ru), tungsten (W), or other similar materials. In a specific example, the first electrode 3310 may be subjected to a dry etch with a slope. For example, the slope may be about 60 degrees.
Fig. 34A to 34C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of a transfer process of the single crystal acoustic resonator device according to an example of the present invention. As shown, these figures illustrate the method steps of forming a first passivation layer 3410 overlying the first electrode 3310 and piezoelectric film 3220. In one example, the first passivation layer 3410 may include silicon nitride (SiN), silicon oxide (SiO), or the likex) Or other similar material. In a specific example, the first passivation layer 3410 may have a thickness ranging from about 50nm to about 100 nm.
Fig. 35A to 35C are diagrams illustrating a single crystal acoustic wave resonator according to an example of the present inventionVarious cross-sectional views of the device and simplified diagrams of method steps of a transfer process for a single crystal acoustic wave resonator device. As shown, these figures illustrate the method steps of forming a support layer 3510 overlying a first electrode 3310 and piezoelectric film 3220. In an example, the support layer 3510 can comprise silicon dioxide (SiO)2) Silicon nitride (SiN), or other similar materials. In a specific example, the support layer 3510 can be deposited at a thickness of about 2-3 μm. As described above, in the case of a PSG sacrificial layer, other support layers (e.g., SiN) may be usedx)。
Fig. 36A to 36C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of a transfer process of the single crystal acoustic resonator device according to an example of the present invention. As shown, these figures illustrate optional method steps for treating the support layer 3510 (to form the support layer 3511) in region 3610. In an example, the process can include partially etching the support layer 3510 to create a planar bonding surface. In a particular example, the process may include a cavity region. In other examples, this step may be replaced with a polishing process such as a chemical mechanical planarization process.
Fig. 37A to 37C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device and method steps of a transfer process of the single-crystal acoustic wave resonator device according to an example of the present invention. As shown, these figures illustrate the method steps of forming air cavity 3710 (to form support layer 3512) within a portion of support layer 3511. In an example, the formation of the cavity can include an etching process that terminates at the first passivation layer 3410.
Fig. 38A to 38C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of a transfer process of the single crystal acoustic resonator device according to an example of the present invention. As shown, these figures illustrate method steps for forming one or more cavity vents 3810 within a portion of the piezoelectric film 3220 through the first passivation layer 3410. In one example, the cavity vent 3810 is connected to the air cavity 3710.
Fig. 39A to 39C are various cross-sectional views illustrating a single crystal acoustic wave resonator device according to an example of the present invention and a single crystal acoustic wave resonanceA simplified diagram of method steps of a transfer process of a device. As shown, these figures illustrate a support layer 3512 overlying a bonded substrate 3910 for flip-chip device and physical coupling. In an example, the bonded substrate 3910 may include a silicon (Si), sapphire (Al) overlay2O3) Silicon dioxide (SiO)2) A bonding support layer 3920 (SiO) over a substrate of silicon carbide (SiC) or other similar material2Or similar material). In a particular embodiment, the bonding support layer 3920 of the bonded substrate 3910 is physically coupled to the polishing support layer 3512. Additionally, the physical coupling process may include a room temperature bonding process followed by an annealing process at 300 degrees celsius.
Fig. 40A to 40C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of a transfer process of the single crystal acoustic resonator device according to an example of the present invention. As shown, these figures illustrate the method steps of removing the growth substrate 3210 or otherwise transferring the piezoelectric film 3220. In an example, the removal process may include a grinding process, a blanket etching process, a thin film transfer process, an ion implantation transfer process, a laser crack transfer process, and the like, and combinations thereof.
Fig. 41A to 41C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device and method steps of a transfer process of the single-crystal acoustic wave resonator device according to an example of the present invention. As shown, these figures illustrate the method steps for forming an electrode contact via 4110 within a piezoelectric film 3220 overlying a first electrode 3310. The via formation process may include various types of etching processes.
Fig. 42A to 42C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of a transfer process of the single crystal acoustic resonator device according to an example of the present invention. As shown, these figures illustrate the method steps of forming a second electrode 4210 overlying a piezoelectric film 3220. In one example, forming the second electrode 4210 includes depositing molybdenum (Mo), ruthenium (Ru), tungsten (W), or other similar materials; the second electrode 4210 is then etched to form electrode cavities 4211 and portions 4211 are removed from the second electrode to form the top metal 4220. In addition, the top metal 4220 is physically coupled to the first electrode 3310 through an electrode contact via 4110.
Fig. 43A to 43C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of a transfer process of the single crystal acoustic resonator device according to an example of the present invention. As shown, these figures illustrate method steps for forming a first contact metal 4310 overlying a portion of the second electrode 4210 and a portion of the piezoelectric film 3220, and forming a second contact metal 4311 overlying a portion of the top metal 4220 and a portion of the piezoelectric film 3220. In an example, the first contact metal and the second contact metal may include gold (Au), aluminum (Al), copper (Cu), nickel (Ni), aluminum copper (AlCu), or other similar materials. This figure also shows the method steps of forming a second passivation layer 4320 overlying the second electrode 4210, the top metal 4220 and the piezoelectric film 3220. In an example, the second passivation layer 4320 may include silicon nitride (SiN), silicon oxide (SiO)x) Or other similar material. In a specific example, the second passivation layer 4320 may have a thickness ranging from about 50nm to about 100 nm.
Fig. 44A to 44C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device and method steps of a transfer process of the single-crystal acoustic wave resonator device according to another example of the present invention. As shown, these figures illustrate the method steps of processing the second electrode 4210 and the top metal 4220 to form a processed second electrode 4410 and a processed top metal 4420. This step may follow the formation of the second electrode 4210 and the top metal 4220. In one example, the processing of the two components includes depositing molybdenum (Mo), ruthenium (Ru), tungsten (W), or other similar materials; the material is then etched (e.g., dry etched, etc.) to form a processed second electrode 4410 with an electrode cavity 4412 and a processed top metal 4420. By removing portion 4411, the processed top metal 4420 remains separated from the processed second electrode 4410. In a specific example, the processed second electrode 4410 is characterized by the addition of energy-constraining structures on the processed second electrode 4410 to increase Q.
Fig. 45A to 45C are simplified diagrams illustrating various cross-sectional views of a single crystal acoustic resonator device and method steps of the single crystal acoustic resonator device using a sacrificial layer transfer process according to another example of the present invention. As shown, these figures illustrate the method steps of processing the first electrode 3310 to form the processed first electrode 4510. This step may follow the formation of the first electrode 3310. In one example, the processing of the two components includes depositing molybdenum (Mo), ruthenium (Ru), tungsten (W), or other similar materials; the material is then etched (e.g., dry etched, etc.) to form a processed first electrode 4510 and an electrode cavity, similar to the processed second electrode 4410. Air cavity 3711 shows the change in cavity shape due to the treated first electrode 4510. In a particular example, the processed first electrode 4510 is characterized by the addition of an energy constraining structure on the processed first electrode 4510 to increase Q.
Fig. 46A to 46C are simplified diagrams showing various cross-sectional views of a single-crystal acoustic wave resonator device according to another example of the present invention and method steps of the single-crystal acoustic wave resonator device using a sacrificial layer transfer process. As shown, these figures illustrate method steps for processing the first electrode 3310 to form a processed first electrode 4510 and for processing the second electrode 4210/top metal 4220 to form a processed second electrode 4410/processed top metal 4420. These steps may follow the formation of each respective electrode, as described in fig. 44A-44C and 45A-45C. One of ordinary skill in the art would recognize other variations, modifications, and alternatives.
Fig. 47A to 47C to 59A to 59C illustrate a manufacturing method of an acoustic wave resonator device using a transfer structure with a multilayer mirror structure. In the series of figures described below, the "a" diagram shows a simplified top-down cross-sectional view illustrating a single crystal resonator device according to various embodiments of the present invention. The "B" diagram shows a simplified diagram illustrating a longitudinal cross-section of the same device in the "a" diagram. Similarly, the "C" diagram shows a simplified lateral cross-sectional diagram illustrating the same device in the "a" diagram. In some instances, certain features are omitted to highlight other features and relationships between such features. Those of ordinary skill in the art will appreciate that variations, modifications, and alternatives to the examples shown in the series of figures may be made.
Fig. 47A to 47C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device and method steps of the single-crystal acoustic wave resonator device using a multilayer mirror transfer process according to an example of the present invention. As shown, these figures illustrate the method steps of forming a piezoelectric film 4720 overlying a growth substrate 4710. In an example, the growth substrate 4710 may include silicon (S), silicon carbide (SiC), or other similar materials. Piezoelectric film 4720 may be an epitaxial film comprising aluminum nitride (AlN), gallium nitride (GaN), or other similar materials. Additionally, the piezoelectric substrate may be subjected to thickness trimming.
Fig. 48A to 48C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device and method steps of the single-crystal acoustic wave resonator device using a multilayer mirror transfer process according to an example of the present invention. As shown, these figures illustrate the method steps of forming a first electrode 4810 overlying the surface region of the piezoelectric film 4720. In an example, the first electrode 4810 can include molybdenum (Mo), ruthenium (Ru), tungsten (W), or other similar materials. In a specific example, the first electrode 4810 can be subjected to a slope of dry etching. For example, the slope may be about 60 degrees.
Fig. 49A to 49C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device and method steps of the single-crystal acoustic wave resonator device using a multilayer mirror transfer process according to an example of the present invention. As shown, these figures illustrate the method steps for forming a multilayer mirror or reflector structure. In one example, the multilayer mirror includes at least one pair of layers, with a low impedance layer 4910 and a high impedance layer 4920. Two pairs of low/high impedance layers (low impedance layers: 4910 and 4911; high impedance layers: 4920 and 4921) are shown in fig. 49A to 49C. In an example, the mirror/reflector region may be larger than and may surround the resonator region. In one embodiment, each layer thickness is approximately 1/4 times the wavelength of the acoustic wave at the target frequency. These layers may be deposited and subsequently etched in sequence, or each layer may be deposited and etched separately. In another example, the first electrode 4810 can be patterned after the mirror structure is patterned.
Fig. 50A to 50C are diagrams illustrating a single crystal acoustic wave resonator according to an example of the present inventionVarious cross-sectional views of the device and simplified diagrams of method steps of a single crystal acoustic resonator device using a multilayer mirror transfer process. As shown, these figures illustrate the method steps of forming the support layer 5010 overlying the mirror structure ( layers 4910, 4911, 4920, and 4921), the first electrode 4810, and the piezoelectric film 4720. In an example, the support layer 5010 can include silicon dioxide (SiO)2) Silicon nitride (SiN), or other similar materials. In a specific example, the support layer 5010 can be deposited at a thickness of about 2-3 μm. As described above, other support layers (e.g., SiN) may be usedx)。
Fig. 51A to 51C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device and method steps of the single-crystal acoustic wave resonator device using a multilayer mirror transfer process according to an example of the present invention. As shown, these figures illustrate the method steps of polishing the support layer 5010 to form the polishing support layer 5011. In one example, the polishing process may include a chemical mechanical planarization process or the like.
Fig. 52A to 52C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device and method steps of the single-crystal acoustic wave resonator device using a multilayer mirror transfer process according to an example of the present invention. As shown, these figures illustrate the support layer 5011 over the flip device and the physical coupling overlying bond substrate 5210. In an example, the bonded substrate 5210 may include a silicon (Si), sapphire (Al) coating2O3) Silicon dioxide (SiO)2) A bonding support layer 5220 (SiO) over a substrate of silicon carbide (SiC) or other similar material2Or similar material). In a particular embodiment, the bonding support layer 5220 of the bonding substrate 5210 is physically coupled to the polishing support layer 5011. Additionally, the physical coupling process may include a room temperature bonding process followed by an annealing process at 300 degrees celsius.
Fig. 53A to 53C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device and method steps of the single-crystal acoustic wave resonator device using a multilayer mirror transfer process according to an example of the present invention. As shown, these figures illustrate method steps for removing the growth substrate 4710 or otherwise transferring the piezoelectric film 4720. In an example, the removal process may include a grinding process, a blanket etching process, a thin film transfer process, an ion implantation transfer process, a laser crack transfer process, and the like, and combinations thereof.
Fig. 54A to 54C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device and method steps of the single-crystal acoustic wave resonator device using a multilayer mirror transfer process according to an example of the present invention. As shown, these figures illustrate the method steps of forming an electrode contact via 5410 within the piezoelectric film 4720 overlying the first electrode 4810. The via formation process may include various types of etching processes.
Fig. 55A to 55C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device and method steps of the single-crystal acoustic wave resonator device using a multilayer mirror transfer process according to an example of the present invention. As shown, these figures illustrate the method steps of forming a second electrode 5510 overlying the piezoelectric film 4720. In one example, forming the second electrode 5510 includes depositing molybdenum (Mo), ruthenium (Ru), tungsten (W), or other similar materials; the second electrode 5510 is then etched to form an electrode cavity 5511 and a portion 5511 is removed from the second electrode to form a top metal 5520. In addition, the top metal 5520 is physically coupled to the first electrode 5520 through the electrode contact via 5410.
Fig. 56A to 56C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device and method steps of the single-crystal acoustic wave resonator device using a multilayer mirror transfer process according to an example of the present invention. As shown, these figures illustrate method steps for forming a first contact metal 5610 overlying a portion of the second electrode 5510 and a portion of the piezoelectric film 4720 and forming a second contact metal 5611 overlying a portion of the top metal 5520 and a portion of the piezoelectric film 4720. In an example, the first contact metal and the second contact metal may include gold (Au), aluminum (Al), copper (Cu), nickel (Ni), aluminum copper (AlCu), or other similar materials. This figure also shows the method steps of forming a second passivation layer 5620 overlying second electrode 5510, top metal 5520, and piezoelectric film 4720. In one example, the second passivation layer 5620 may include silicon nitride (SiN),Silicon oxide (SiO)x) Or other similar material. In a particular example, the second passivation layer 5620 may have a thickness ranging from about 50nm to about 100 nm.
Fig. 57A to 57C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device according to another example of the present invention and method steps of the single-crystal acoustic wave resonator device using a multilayer mirror transfer process. As shown, these figures illustrate the method steps of processing the second electrode 5510 and top metal 5520 to form a processed second electrode 5710 and a processed top metal 5720. This step may follow the formation of the second electrode 5710 and the top metal 5720. In one example, the processing of the two components includes depositing molybdenum (Mo), ruthenium (Ru), tungsten (W), or other similar materials; the material is then etched (e.g., dry etched, etc.) to form a processed second electrode 5410 and electrode cavity 5712 and processed top metal 5720. By removing portion 5711, treated top metal 5720 remains separated from treated second electrode 5710. In a particular example, the process imparts a greater thickness to the second electrode and top metal while creating the electrode cavity 5712. In a specific example, the processed second electrode 5710 is characterized by the addition of an energy-constraining structure on the processed second electrode 5710 to increase Q.
Fig. 58A to 58C are simplified diagrams showing various cross-sectional views of a single-crystal acoustic wave resonator device according to another example of the present invention and method steps of the single-crystal acoustic wave resonator device using a multilayer mirror transfer process. As shown, these figures illustrate method steps for processing the first electrode 4810 to form a processed first electrode 5810. This step may follow the formation of the first electrode 4810. In one example, the processing of the two components includes depositing molybdenum (Mo), ruthenium (Ru), tungsten (W), or other similar materials; the material is then etched (e.g., dry etched, etc.) to form a processed first electrode 5810 and an electrode cavity, similar to the processed second electrode 5710. In contrast to the first two examples, there is no air cavity. In a particular example, the processed first electrode 5810 is characterized by the addition of energy constraining structures on the processed first electrode 5810 to increase Q.
Fig. 59A to 59C are simplified diagrams illustrating various cross-sectional views of a single-crystal acoustic wave resonator device according to another example of the present invention and method steps of the single-crystal acoustic wave resonator device using a multilayer mirror transfer process. As shown, these figures illustrate method steps for processing the first electrode 4810 to form a processed first electrode 5810 and processing the second electrode 5510/top metal 5520 to form a processed second electrode 5710/processed top metal 5720. These steps may follow the formation of each respective electrode, as described in fig. 57A to 57C and fig. 58A to 58C. One of ordinary skill in the art would recognize other variations, modifications, and alternatives.
In each of the foregoing examples relating to transfer processes, the energy-constraining structure may be formed on the first electrode, the second electrode, or both. In one example, these energy constraining structures are mass-loaded regions surrounding the resonator region. The resonator area is an area where the first electrode, the piezoelectric layer and the second electrode overlap. A larger mass load in the energy-confining structure will lower the cutoff frequency of the resonator. The cutoff frequency is a lower limit or an upper limit of a frequency at which an acoustic wave can propagate in a direction parallel to the surface of the piezoelectric film. Thus, the cutoff frequency is the resonant frequency at which the wave propagates in the thickness direction and is determined by the overall stack structure of the resonator in the vertical direction. In a piezoelectric film (e.g., AIN), an acoustic wave having a frequency lower than the cutoff frequency can propagate in a direction parallel to the film surface, i.e., the acoustic wave exhibits a high-band cutoff dispersion characteristic. In this case, the mass-loaded region around the resonator provides a barrier that prevents the acoustic wave from propagating outside the resonator. This feature thus improves the quality factor of the resonator and improves the performance of the resonator, and thus the filter.
Further, the top single crystal piezoelectric layer may be replaced with a polycrystalline piezoelectric film. In such films, the lower portion near the interface with the substrate is of poor crystalline quality, the grain size is smaller, and the distribution of piezoelectric polarization orientation is wider than the upper portion of the film near the surface. This is due to the polycrystalline growth of the piezoelectric film, i.e., nucleation and the initial film having random crystal orientations. Considering AIN as a piezoelectric material, the growth rate along the c-axis or polarization orientation is higher than other crystal orientations, and as the film grows thicker, the proportion of crystal grains with the c-axis perpendicular to the growth surface increases. In polycrystalline AIN films, typically about 1 μm thick, the upper portion of the film near the surface has better crystalline quality and better piezoelectric polarization orientation. By utilizing the thin film transfer process contemplated by the present invention, the polycrystalline film upper portion can be used in a high frequency BAW resonator having an extremely thin piezoelectric film. This can be accomplished by removing a portion of the piezoelectric layer during growth of the substrate. There may of course be other variations, modifications, and alternatives.
In one example, the present invention provides a high performance, subminiature band-pass Bulk Acoustic Wave (BAW) Radio Frequency (RF) filter for 5.2GHz Wi-Fi applications covering the U-NII-1 and U-NII-2A bands.
Fig. 60 is a simplified diagram illustrating filter passband requirements in the radio frequency spectrum according to an example of the present invention. As shown, spectrum 6000 shows a range from 3.0GHz to 6.0 GHz. Here, the first application band 6010(3.3GHz-4.2GHz) is configured for 5G applications. The frequency band includes 5G sub-band 6011(3.3GHz-3.8GHz), which further includes LTE sub-bands 6012(3.4GHz-3.6GHz), 6013(3.6GHz-3.8GHz), and 6014(3.55GHz-3.7 GHz)). The second application band 6020(4.4GHz-5.0GHz) includes sub-bands 6021 for chinese specific applications. The third application band 6030 includes UNII-1 band 6031(5.15GHz-5.25GHz) and UNII-2A band 6032(5.25GHz-5.33 GHz). LTE band 6033 is the same frequency range as UNII-1 band 6031. Finally, the fourth application band 6040 includes UNII-2C band 6041(5.490GHz-5.735GHz), UNII-3 band 6042(5.735GHz-5.85GHz), and UNII-4 band 6043(5.85GHz-5.925 GHz). LTE band 6044 shares the same frequency range as UNII-2C band 6041, sub-band 6045 overlaps the frequency range of UNII-4 band 6043, and LTE band 6046 overlaps a smaller sub-segment of the same frequency range (5.855GHz-5.925 GHz). One of ordinary skill in the art would recognize other variations, modifications, and alternatives.
In one embodiment, the inventive filter utilizes the single crystal BAW technique as described in the previous figures. The filter provides low insertion loss and meets stringent rejection requirements, and is capable of co-existing with U-NII-2C and U-NII-3 frequency bands. The high rated power meets the stringent power requirements of the latest Wi-Fi standard.
Figure 61 is a simplified diagram illustrating an overview of the key market for an acoustic rf filter application according to an example of the present invention. The application graph 6100 of the 5.2GHz BAW RF filter shows a mobile device, a smart phone, an automobile, a Wi-Fi triple-band router, a triple-band mobile device, a triple-band smart phone, an integrated cable modem, a Wi-Fi triple-band access point, an LTE/LAA cell, and the like. Fig. 62 provides a schematic diagram of the spectrum used in a three-frequency Wi-Fi system.
Figure 62 is a simplified diagram illustrating the 5.2GHz radio frequency filter application domain in a tri-band Wi-Fi radio according to an example of the invention. As shown, the RF filters used by the communication device 6210 may be configured for specific applications in three separate operating bands. In a particular example, the application zone 6220 operates at 2.4GHz and includes computing devices and mobile devices, the application zone 6230 operates at 5.2GHz and includes televisions and display devices, and the application zone 6240 operates at 5.6GHz and includes video game consoles and handheld devices. One of ordinary skill in the art would recognize other variations, modifications, and alternatives.
The invention includes resonator and RF filter devices using textured polycrystalline piezoelectric material (deposited using PVD methods) and single crystal piezoelectric material (grown on a seed substrate using CVD techniques). Various substrates may be used to fabricate acoustic devices, such as silicon substrates of various crystal orientations, and the like. Additionally, the method may use a sapphire substrate, a silicon carbide substrate, a gallium nitride (GaN) bulk substrate, or an aluminum nitride (AlN) bulk substrate. The method may also use a GaN template, an AIN template, and an AlxGal-xN template (where x varies from 0.0 to 1.0). These substrates and templates may have polar, non-polar or semi-polar crystal orientations. Additionally, the piezoelectric material deposited on the substrate may include at least one selected from the group consisting of: AIN, GaN, InN, InGaN, AlInN, AlInGaN, ScAIN, ScAlGaN, ScGaN, ScN, BAIN, BALScN, and BN.
Resonator and filter devices may employ a variety of process technologies including, but not limited to, solid-state assembled resonators (SMRs), Film Bulk Acoustic Resonators (FBARs), or single crystal acoustic resonators (XBAWs). Representative cross-sections are shown in fig. 63A-63C below. For the sake of clarity, the terms "top" and "bottom" as used in this specification are not broad terms with respect to the direction of gravity. Rather, the terms "top" and "bottom" may be mutually referenced in the context of the present device and associated circuitry. One of ordinary skill in the art would recognize other variations, modifications, and alternatives.
In one example, the piezoelectric layer ranges between 0.1 μm to 2.0 μm and is optimized to produce the best combination of resistance and acoustic loss. The top and bottom electrodes have a thickness in the range of 250 to 2500 angstroms and the metal is comprised of a refractory metal having a high acoustic speed and low resistivity. The resonators are "passivated" with a dielectric (not shown in fig. 63A-63C) that is composed of nitride and/or oxide and ranges between 100 and 2000 angstroms. The dielectric layer is used to adjust the resonant frequency of the resonator. It is particularly noted that the metal resistivity between adjacent resonators on a metal layer called interconnect metal is reduced. The thickness of the interconnect metal ranges between 500 angstroms and 5 microns. In the case of SMR, the resonator contains at least one air cavity interface, and in the case of FBAR and XBAW, the resonator contains at least two air cavity interfaces. The shape of the selected resonator is from asymmetric shapes including elliptical, rectangular and polygonal. In addition, the resonator contains a reflective feature near the resonator edge on one or both sides of the resonator.
Fig. 63A to 63C are simplified cross-sectional views illustrating resonator devices according to various examples of the present invention. More particularly, device 6301 in fig. 63A shows a BAW resonator device including an SMR, fig. 63B shows a BAW resonator device including an FBAR, and fig. 63C shows a BAW resonator device having a single crystal XBAW. As shown by SMR device 6301, reflector device 6320 is configured to overlie substrate member 6310. The reflector device 6320 may be a Bragg (Bragg) reflector or the like. The bottom electrode 6330 is configured as an overlying reflector device 6320. A polycrystalline piezoelectric layer 6340 is configured to overlie the bottom electrode 6330. Additionally, a top electrode 6350 is configured overlying the polycrystalline layer 6340. As shown in FBAR device 6302, the layered structure comprising bottom electrode 6330, poly layer 6340, and top electrode 6350 remains unchanged. Substrate member 6311 includes air cavity 6312 and a dielectric layer is formed overlying substrate member 6311 and covering air cavity 6312. As shown in XBAW device 6303, substrate member 6311 also contains air cavity 6312, but bottom electrode 6330 is formed in the region of air cavity 6312. A single crystal piezoelectric layer is formed overlying substrate member 6311, air cavity 6312, and bottom electrode 6341. In addition, a top electrode 6350 is formed overlying a portion of the monocrystalline layer 6341. These resonators may be scaled and configured into the circuit configurations shown in fig. 64A-64C.
The RF filter circuit may include various circuit topologies, including a modified lattice circuit configuration ("I") 6401, a lattice circuit configuration ("P") 6402, and a ladder circuit configuration ("HI") 6403, as shown in fig. 64A, 64B, and 64C, respectively. These figures are representative lattice and ladder diagrams of acoustic wave filter designs including resonators and other passive components. The lattice configuration and the modified lattice configuration include a differential input port 6410 and a differential output port 6450, and the ladder configuration includes a single-ended input port 6411 and a single-ended output port 6450. In the grid configuration, the nodes are labeled as the top node (tl-t3) and the bottom node (bl-b3), while in the ladder configuration, the nodes are labeled as a set of nodes (nl-n 4). The series resonator element (in cases I, II and III) is shown with a white central element 6421- > 6424, while the parallel resonator element has a dark central circuit element 6431- > 6434. The resonant frequency of the series elements is higher than the resonant frequency of the parallel elements to form a filter skirt at the passband frequency. The inductors 6441-6443 and any other matching elements shown in the modified lattice circuit diagram (fig. 64A) may be included on-chip (adjacent to the resonator elements) or off-chip (near the resonator chips) and may be used to adjust the passband and/or impedance matching of the filter circuit (to achieve the return loss specification). The filter circuit includes a resonator having at least two resonant frequencies. The center of the passband frequency can be adjusted by a trimming step (using ion milling or other similar techniques) and the filter skirt shape can be adjusted by trimming individual resonator elements in the circuit (to change the resonant frequency of one or more of the elements).
In one example, the present invention provides an RF filter circuit device in a ladder configuration. The device may include an input port, a first node coupled to the input port, and a first resonator coupled between the first node and the input port. The second node is coupled to the first node, and the second resonator is coupled between the first node and the second node. The third node is coupled to the second node, and the third resonator is coupled between the second node and the third node. The fourth node is coupled to the third node, and the fourth resonator is coupled between the third node and the output port. Additionally, an output port is coupled to the fourth node. One of ordinary skill in the art would recognize other variations, modifications, and alternatives.
Each of the first resonator, the second resonator, the third resonator, and the fourth resonator may include a capacitance device. Each such capacitive device may include a substrate member having a cavity region and an upper surface region adjoining an opening in the first cavity region. Each capacitive device can include a bottom electrode within a portion of the cavity region and a piezoelectric material overlying the upper surface region and the bottom electrode. Furthermore, each capacitive device may include a top electrode overlying the single crystal material and the bottom electrode and an insulating material overlying the top electrode and configured with a thickness to tune the resonator.
The device also includes a series configuration including an input port, a first node, a first resonator, a second node, a second resonator, a third node, a third resonator, a fourth node, and an output port. A separate parallel-configured resonator is coupled to each of the first, second, third and fourth nodes. The parallel configuration includes a first parallel configuration resonator, a second parallel configuration resonator, a third parallel configuration resonator, and a fourth parallel configuration resonator. Additionally, the circuit response may be configured between the input port and the output port and configured according to a series configuration and a parallel configuration to achieve transmission loss from a pass band having a characteristic frequency centered at 5.2GHz and a bandwidth of 5.170GHz to 5.330GHz such that the characteristic frequency centered at 5.2GHz begins tuning from a lower frequency of about 4GHz to 5.1 GHz.
In a specific example, the first piezoelectric material, the second piezoelectric material, the third piezoelectric material and the fourth piezoelectric material are substantially single crystal aluminum nitride bearing material or aluminum scandium nitride bearing material, single crystal gallium nitride bearing material or gallium aluminum bearing material, etc. In another embodiment, the piezoelectric materials each include a polycrystalline aluminum nitride carrier material or an aluminum scandium carrier material or a polycrystalline gallium nitride carrier material or a gallium aluminum carrier material.
In a specific example, the series configuration forms a resonance profile and an anti-resonance profile. The parallel configuration also forms a resonance profile and an anti-resonance profile. These profiles shift the resonance profile from the series configuration relative to the anti-resonance profile from the parallel configuration to form the pass band.
In a specific example, the pass band is characterized by band edges on each side of the pass band and has an amplitude difference in the range of 10dB to 60 dB. The passband has a pair of band edges; each band edge has a transition from the pass band to the stop band such that the transition does not exceed 250 MHz. In another example, the passband may include a pair of bandedges, each of which may have a transition from the passband to the stopband such that the transition ranges from 5MHz to 250 MHz.
In a specific example, each of the first, second, third, and fourth insulating materials comprises a silicon nitride carrier material or an oxide carrier material configured with a silicon nitride material.
In a particular example, the present device may also include several features. The device may also include a stop band at frequencies above the pass band. The stop band may range from 5.490GHz to 5.835 GHz. The device may also include an insertion loss of 2.1dB and an amplitude variation characterizing a 0.7dB passband. Furthermore, the device may comprise an attenuation of up to 40dB for the frequency range of 1GHz to 5GHz or an attenuation of up to 48dB for the frequency range of 5.9GHz to 11 GHz. The device may also include a return loss characterizing up to a 15dB passband, and the device may operate between-40 degrees celsius and 85 degrees celsius. The device may also include a maximum power of 30dBm or 1W within the passband. In addition, the pass band may be configured for the U-NII-1+ U-NII-2 Hermitian band and IEEE 802.11a channel plan.
In a specific example, the instant device may be configured as a Bulk Acoustic Wave (BAW) filter device. Each of the first resonator, the second resonator, the third resonator, and the fourth resonator may be a BAW resonator. Similarly, each of the first parallel resonator, the second parallel resonator, the third parallel resonator, and the fourth parallel resonator may be a BAW resonator. The device may also include one or more additional resonator devices numbered N through M, where N is 4 and M is 20. Similarly, the instant devices may also include one or more additional parallel resonator devices numbered N through M, where N is 4 and M is 20.
In one example, the present invention provides an RF circuit device in a lattice configuration. The device may include a differential input port, a top series configuration, a bottom series configuration, a first lattice configuration, a second lattice configuration, and a differential output port. The top series configuration may include a first top node, a second top node, and a third top node. The first top resonator may be coupled between the first top node and the second top node, and the second top resonator may be coupled between the second top node and the third top node. Similarly, the bottom series configuration may include a first bottom node, a second bottom node, and a third bottom node. The first bottom resonator may be coupled between the first bottom node and the second bottom node, and the second bottom resonator may be coupled between the second bottom node and the third bottom node.
In an example, the first lattice configuration includes a first parallel resonator cross-coupled with a second parallel resonator and coupled between a first top resonator of the top series configuration and a first bottom resonator of the bottom series configuration. Similarly, the second lattice configuration may include a first parallel resonator cross-coupled with a second parallel resonator and coupled between a second top resonator of the top series configuration and a second bottom resonator of the bottom series configuration. Both the top series configuration and the bottom series configuration may be coupled to a differential input port and a differential output port.
In a specific example, the device further includes a first BALUN (BALUN) coupled to the differential input port and a second BALUN (BALUN) coupled to the differential output port. The device may also include an inductive device coupled between the differential input port and the differential output port. In a specific example, the device may further include: a first inductive device coupled between a first top node of the top series arrangement and a first bottom node of the bottom series arrangement; a second inductive device coupled between a second top node of the top series arrangement and a second bottom node of the bottom series arrangement; and a third inductive device coupled between a third top node of the top series configuration and a third bottom node of the bottom series configuration.
The packaging method includes, but is not limited to, Wafer Level Packaging (WLP), WLP capping wafer method, flip chip, chip bonding wire, as shown in fig. 65 and 66. The one or more RF filter chips and the one or more filter bands may be packaged within the same housing configuration. Each RF filter band within the package may include one or more resonator filter chips and may use passive components (capacitors, inductors) to tailor bandwidth and spectral characteristics. For tri-band Wi-Fi system applications, packaging configurations that include three RF filter bands (including 2.4GHz, 5.2GHz, and 5.6GHz band pass schemes) can use BAW radio frequency filter technology. The 2.4GHz filter scheme may be Surface Acoustic Wave (SAW) or BAW, while the 5.2GHz and 5.6GHz bands may be BAW, since BAW has high frequency capability.
Fig. 65A is a simplified diagram of a packaging method according to an example of the invention. As shown, the packaging of the device 6501 uses conventional die bonding of the RF filter die 6510 to the substrate 6520 of the package and metal bonding wires 6530 from the circuit interface 6540 to the RF filter chip.
Fig. 65B is a simplified diagram of a packaging method according to an example of the invention. As shown, the packaging of device 6602 uses flip-chip Wafer Level Packaging (WLP), indicating an RF filter silicon die 6510 that is assembled to circuit interface 6540 using copper pillars 6531 or other high conductivity interconnects.
FIG. 66 is a simplified diagram of a packaging method according to an example of the invention. Device 6600 shows an alternative version of WLP, utilizing BAW radio frequency filter circuit MEMS device 6630 and substrate 6610 to cap wafer 6640. In an example, the cap wafer 6640 may include Through Silicon Vias (TSVs) to electrically connect the RF filter MEMS device 6630 to the top side of the cap wafer (not shown in the figures). The cap wafer 6640 may be coupled to a dielectric layer 6620 overlying the substrate 6610 and encapsulated by an encapsulant 6650.
In one example, the present filter passes frequencies in the range of 5.17GHz to 5.33GHz and rejects frequencies outside the pass band. Additional functionality of the 5.2GHz acoustic wave filter circuit is provided below. Circuit symbols for the reference RF filter building blocks are provided in fig. 67. The electrical performance specification for the 5.2GHz filter is provided in fig. 68 and the passband performance of the filter is provided in fig. 69.
In various examples, the present filter may have certain features. The die configuration may be less than 2mm x 0.5 mm; in a specific example, the die configuration is typically less than 1mm by 0.2 mm. The packaged device has an ultra small form factor, such as 2mm x 2.5mm x 0.9mm, using a conventional die bond wire method, as shown in fig. 65. The WLP packaging approach may provide a smaller form factor. In a specific example, the device is configured with a single-ended 50 ohm antenna and a transmitter/receiver (Tx/Rx) port. The high rejection rate of the device can realize the coexistence with adjacent Wi-Fi UNIT frequency bands. The device is also characterized by high power rating (up to +30dBm), low insertion loss bandpass filter transmission loss below 2.5dB, and performance in the temperature range-40 degrees celsius to +85 degrees celsius, etc. Additionally, in one specific example, the device conforms to RoHS (hazardous materials limitation) and uses Pb-free (lead-free) packaging.
Fig. 67 is a simplified circuit diagram illustrating a 2-port BAW RF filter circuit according to an example of the present invention. As shown, the circuit 6700 includes a first Port ("Port 1") 6711, a second Port ("Port 2") 6712, and a filter 6720. The first port represents a connection from the Transmitter (TX) or Receiver (RX) to the filter 6720 and the second port represents a filter connection from the filter 6720 to the Antenna (ANT).
FIG. 68 is a profile of filter parameters according to an example of the invention. As shown, table 6800 includes the electrical specifications for the 5.2GHz radio frequency resonator filter circuit. The circuit parameters are provided along with specification units, minimum values, and typical and maximum specification values.
Figure 69 is a simplified graph illustrating insertion loss as a function of frequency according to one example of the present invention. As shown, graph 6900 represents a narrow band measurement and modeled response of a 5.2GHz radio frequency filter using a ladder RF filter circuit configuration. The modeled curve 6910 is the transmission loss predicted from a linear simulation tool in conjunction with a nonlinear full 3-dimensional (3D) Electromagnetic (EM) simulation (s 21). The measurement curve 6920 is s21 measured from scattering parameters (s parameters) obtained from the network analyzer test system.
In one example, the present invention provides a Front End Module (FEM) for a 5.2GHz Wi-Fi acoustic resonator RF filter circuit. The device may include a Power Amplifier (PA), a 5.2GHz resonator, and a diversity switch. In a particular example, the device may also include a Low Noise Amplifier (LNA). The PA is electrically coupled to the input node and configurable to either a DC power detector or an RF power detector. The resonator may be disposed between the PA and the diversity switch or between the diversity switch and the antenna. The LNA may be configured to the diversity switch or electrically isolated from the switch. Another 5.2GHZ resonator may be configured between the diversity switch and the LNA. In a specific example, the device integrates a 5.2GHz PA, 5.2GHz Bulk Acoustic Wave (BAW) RF filter, single pole double throw (SP2T) switch, and optional bypassable Low Noise Amplifier (LNA) into a single device. Fig. 70-74 show five FEMS examples according to various embodiments of the invention. In each example, the LNA may be omitted to produce only the transmit module. In the following figures, the numbering scheme of the elements of these FEMs remains the same in fig. 70-74, except for the first two digits corresponding to the figure number.
Fig. 70 is a simplified circuit block diagram illustrating a front end module according to an example of the present invention. As shown, the device 7000 includes a PA 7010, a 5.2GHz resonator 7020, a diversity switch 7030, and an LNA 7040. Here, the input of PA 7010 is electrically coupled to the input node (shown as TX _ IN [2 ]). In a specific example, the PA may be a 5.2GHz PA. Inductor 7011 may also be electrically coupled to the input node. The 5.2GHz resonator 7020 is electrically coupled to the output of the PA 7010. In a specific example, the resonator 7020 can be a 5.2GHz BAW resonator.
IN this case, LNA7040 is configured separately from the aforementioned circuit elements and is electrically coupled to the LNA input (shown as LNA _ IN [16]) and the LNA output (shown as LNA _ OUT [17 ]). As previously described, the LNA7040 may be omitted, which may result in the device being the transmit only module. In a particular embodiment, the coupling capacitors 7041 and 7042 may be configured between the LNA7040 and the LNA input and LNA output, respectively. The signal filter 7043 may be configured between the LNA and the coupling capacitor 7041. In this case, the signal filter 7043 may be a band-stop filter. Additionally, the LNA7040 may be configured in the switch feedback loop 7044. In a particular example, the LNA7040 can be a bypassable LNA.
In one example, device 7000 may be configured with a power detector, which may be a DC power detector or an RF power detector. The DC power detector has a voltage output and is electrically coupled to the PA at a DC power detection node (shown as DC _ PDET [6 ]). In a specific example, a diode is configured between the PA and the DC power detector. The RF power detector has an RF output from a directional coupler 7013 configured at the PA output.
In one example, the present device design provides a compact form factor, with integrated matching minimizing layout area in the application. The PA can be optimized for a 5V supply voltage, saving power consumption while maintaining high linear output power and throughput. Moreover, the integrated BAW filter reduces the overall size of Wi-Fi radio applications, allowing the 5.2GHz radio band to co-exist with adjacent 2.4GHz and 5.6GHz bands in a tri-band router configuration. One of ordinary skill in the art will recognize other variations, modifications, and alternatives to the above.
Fig. 71 is a simplified circuit block diagram illustrating a front end module according to an example of the present invention. The numbering scheme is the same as in fig. 70, except that the first two digits refer to "71". As shown, device 7100 is similar to device 7000 in fig. 70, except for the configuration of 5.2GHz resonator 7120. Here, the resonator 7120 is disposed between the pole of the diversity switch 7130 and the antenna and the coupling capacitor 7132. There may of course be other variations, modifications, and alternatives.
Fig. 72 is a simplified circuit block diagram illustrating a front end module according to an example of the invention. The numbering scheme is the same as for fig. 70, except that the first two digits refer to "72". As shown, device 7200 is similar to device 7000 except that an additional 5.2GHz resonator 7221 is disposed between a throw of diversity switch 7230 and the input of LNA 7240 and signal filter 7243. In this example, the switch 7230 is not coupled to the output node and the LNA is not coupled to the LNA input node. Similar to the first resonator 7220, the second resonator 7221 may also be a 5.2GHz BAW resonator. There may of course be other variations, modifications, and alternatives.
Fig. 73 is a simplified circuit block diagram illustrating a front end module according to an example of the present invention. The numbering scheme is the same as in fig. 70, except that the first two digits refer to "73". As shown, device 7300 is similar to device 7200 of fig. 72 except that diversity switch 7330 is a single pole, three throw (SP3T) switch and LNA 7340 no longer includes a switch feedback loop. Conversely, the output of LNA 7340 is electrically coupled to the third throw of switch 7340. There may of course be other variations, modifications, and alternatives.
Fig. 74 is a simplified circuit block diagram illustrating a front end module according to an example of the invention. The numbering scheme is the same as for fig. 70, except that the first two digits refer to "74". As shown, device 7400 is similar to device 7100 in fig. 71, with a 5.2GHz resonator 7420 configured between the switch 7030 and the antenna, but is also similar to device 7300 in fig. 73, with the output of LNA 7440 electrically coupled to the third throw of switch 7430 (which is the SP3T switch). There may of course be other variations, modifications, and alternatives.
As understood by the present inventors, in accordance with some embodiments of the present invention, the above-described piezo-based BAW resonator filter (e.g., with reference to fig. 64A-64C) may be further modified to replace (or add) resonators 6421 with series band-stop resonators configured to have an anti-resonant frequency in a stop band below the pass band. In some approaches, parallel band-stop resonators may be added to the inputs of the resonators 6421, where the parallel band-stop resonators are configured to have a resonant frequency in a stop band above the pass band. It should be understood that the anti-resonant frequencies of the series band-stop resonators coupled to the input and output of the filter may be different and may overlap each other. Also, the resonant frequencies of the parallel band-stop resonators coupled to the input and output of the filter may be different and may overlap each other.
Accordingly, a BAW resonator filter according to an embodiment of the present invention may be used to improve the stop band performance of a filter configured to provide a 5.17GHz to 5.33GHz pass band. BAW resonator filters according to an embodiment of the invention may also be used to improve the stop band performance of filters configured to provide a pass band of 5.49GHz to 5.835 GHz. It should be appreciated that embodiments in accordance with the invention may be provided by including at least one stop band series or parallel resonator coupled to an input or output of a BAW resonator filter. Additionally, the BAW resonator filter may be any topology filter circuit, such as a ladder or lattice topology.
In other embodiments, a BAW resonator filter comprising series band-stop resonators may be combined with a BAW resonator filter comprising parallel band-stop resonators and a switch to select one of the BAW resonator filters to operate. For example, in a first state, the switch may couple an input signal to a BAW resonator filter comprising series band-stop resonators, and in a second state, the switch may couple an input signal to a BAW resonator filter comprising parallel band-stop resonators. Accordingly, in some embodiments, two different BAW resonator filters (each having a different passband) may be integrated into a single device, where a switch may be used to select a particular BAW resonator filter for a particular application.
It should also be appreciated that series band-stop resonators can be formed using band-stop mass loading structures having a mass greater than the mass of the pass-band mass loading structures on the series band-pass resonators. Accordingly, the method for forming a bandpass resonator may be adapted to form a series bandstop resonator as described herein by increasing the mass load on the bandstop resonator relative to the mass load used to form the bandpass resonator. For example, the first series band-pass resistive resonator may be formed with a stop band mass loading structure having a mass greater than the pass band mass loading structure on the parallel band-pass resonators. Further, the series band-stop resonator can include a band-stop mass loading structure having a mass greater than the pass-band mass loading structure.
Figure 75 is a schematic diagram of a BAW resonator filter 7500 including a BAW resonator bandpass filter ladder 7505 and first and second series bandstop resonators 7510 and 7515 in accordance with some embodiments of the present invention. According to fig. 75, the input node of the BAW resonator bandpass filter ladder 7505 is coupled to a first series bandstop resonator 7510 and the output node of the BAW resonator bandpass filter ladder 7505 is coupled to a second series bandstop resonator 7515.
Fig. 76 is a graph illustrating anti-resonant frequencies of the first series bandstop resonator 7510 and the second series bandstop resonator 7515 in the BAW resonator filter of fig. 75 in some embodiments according to the invention. According to fig. 76, the BAW resonator filter of fig. 75 provides a bandpass filter with a passband in the frequency range of about 5.49GHz to about 5.835 GHz. The first series band-stop resonator 7510 and the second series band-stop resonator 7515 are configured to provide anti-resonance frequency peaks 7520 and 7525 and rejection nulls (rejectionnull)7607 and 7608 near below the passband. It should be appreciated that while the suppression zeros 7607 and 7608 in fig. 76 are near below the passband lower edge, in some embodiments the corresponding suppression zeros may be below but not necessarily near the passband lower edge. In some embodiments, anti-resonance frequency peaks 7520 and 7525 are approximately aligned with rejection zeros 7607 and 7608 in a stop band near below the passband of BAW resonator filter response 7524.
As described herein, according to some embodiments of the invention, a resonant frequency peak or anti-resonant frequency peak associated with a series or parallel band-stop resonator may be aligned with a rejection zero present in the filter circuit response. It should be understood that in some embodiments, the resonant frequency peaks or anti-resonant frequency peaks associated with series or parallel band-stop resonators may provide a rejection zero as part of the filter response without alignment with other existing rejection zeros included in the filter response.
As understood by the present inventors, the alignment of the anti-resonant frequency peaks 7520 and 7525 from the first series band-stop resonator 7510 and the second series band-stop resonator 7515 with the rejection zeros in the filter response can provide a combined attenuation in the rejection band that is higher than would be provided if the first series band-stop resonator 7510 and the second series band-stop resonator 7515 were not included, as shown by the filter response 7524 in fig. 76. In some embodiments, including series band- stop resonators 7510 and 7515 that achieve the alignment described herein can provide at least about an additional 5dB of attenuation compared to a case that does not include first series band-stop resonator 7510 and second series band-stop resonator 7515. In some embodiments, including series band- stop resonators 7510 and 7515 that achieve the alignment described herein can provide at least about an additional 10dB of attenuation for the filter response.
In some embodiments, the resonance frequency peak 7526 of the series bandpass resonator and the anti-resonance frequency peak 7530 of the parallel bandpass resonator are located near the center of the passband. Furthermore, the resonant frequency peak 7535 of the parallel bandpass resonator is below or about the lower edge of the passband and the anti-resonant frequency peaks 7609 and 7610 of the series bandpass resonator are at or above the upper edge of the passband.
Fig. 80 is a schematic diagram of a BAW resonator filter including a BAW resonator bandpass filter lattice point shown in fig. 64A including a first series bandstop resonator 8010 and a second series bandstop resonator 8015 in accordance with some embodiments of the invention. Figure 81 is a schematic diagram of a BAW resonator filter including BAW resonator bandpass filter lattice points shown in figure 64B including a first series bandstop resonator 8110 and a second series bandstop resonator 8115 in accordance with some embodiments of the present invention. According to fig. 80 and 81, a first series band-stop resonator and a second series band-stop resonator may also be added to the input node and the output node of the BAW resonator band-pass filter lattice, respectively, as shown in fig. 64A and 64B, to further improve the stop band performance.
Fig. 82 is a graph illustrating a BAW resonator filter response 8420 including anti-resonant frequencies of the first series bandstop resonator 8010/8110 and the second series bandstop resonator 8015/8115 shown in fig. 80 and 81 in some embodiments according to the invention. According to fig. 82, anti-resonance frequency peaks 8225 and 8220 associated with the first and second series band-stop resonators 8010/8110 and 8015/8115 may be approximately aligned with the suppression zeros 7607 and 7608 in the stopband adjacent below the passband of the BAW resonator filter response 8240 at the passband lower edge. It should be appreciated that while the suppression zeros 7607 and 7608 in fig. 82 are near below the passband lower edge, in some embodiments the corresponding suppression zeros may be below but not necessarily near the passband lower edge. As understood by the present inventors, the anti-resonance frequency peaks from the first series bandstop resonator 8010/8110 and the second series bandstop resonator 8015/8115 aligned with the damping zeros 7607 and 7608 may provide a combined attenuation in the rejection band that is higher than would be provided without the first series bandstop resonator 8010/8110 and the second series bandstop resonator 8015/8115. In some embodiments, including series band-stop resonators 8010/8110 and 8015/8115 that achieve the alignment described herein may provide at least about an additional 5dB of attenuation compared to not including the first series band-stop resonator 8010/8110 and the second series band-stop resonator 8115/8115. In some embodiments, including series bandstop resonators 8010/8010 and 8015/8115 that achieve the alignment described herein may provide at least about an additional 10dB of attenuation.
Figure 77 is a schematic diagram of a BAW resonator filter 7700 including a BAW resonator bandpass filter ladder 7705 and first 7710 and second 7715 parallel band-stop resonators according to some embodiments of the invention. According to fig. 77, the input node of the BAW resonator bandpass filter ladder 7505 is coupled to a first parallel band-stop resonator 7710 and the output node of the BAW resonator bandpass filter ladder 7505 is coupled to a second parallel band-stop resonator 7515.
Fig. 78 is a graph showing resonance frequencies of the first parallel band-stop resonator 7710 and the second parallel band-stop resonator 7715 in the BAW resonator filter shown in fig. 77 according to some embodiments of the present invention. According to fig. 78, the BAW resonator filter of fig. 77 provides a band pass filter having a pass band frequency range of about 5.17GHz to about 5.33 GHz. The first and second parallel band- stop resonators 7710 and 7715 are configured to provide resonant frequency peaks 7805 and 7806 and may be aligned with the rejection zeros 7807 and 7808 in the filter response 7824 above the pass band. It should be appreciated that while the suppression zeros 7807 and 7808 in fig. 78 are above the pass band, in some embodiments, the corresponding suppression zeros may be near above the upper edge of the pass band. In some embodiments, the resonant frequency peak 7815 of the series bandpass resonator and the anti-resonant frequency peak 7810 of the parallel bandpass resonator are located near the center of the passband. Further, the resonant frequency peak 7820 of the parallel bandpass resonator is located below the lower edge of the passband, and the anti-resonant frequency peaks 7811 and 7812 of the series bandpass resonator may be located near above the upper edge of the passband.
As understood by the present inventors, the alignment of the resonant frequency peaks 7805 and 7806 from the first and second parallel band- stop resonators 7710 and 7715 with the rejection zeros 7807 and 7808 in the filter response may provide a combined attenuation in the rejection band that is higher than would be provided without the first and second parallel band- stop resonators 7710 and 7715. In some embodiments, including parallel band- stop resonators 7710 and 7715 to achieve the alignment described herein may provide at least about an additional 5dB of attenuation than if the first and second parallel band- stop resonators 7710 and 7715 were not included. In some embodiments, including parallel band- stop resonators 7710 and 7715 to achieve the alignment described herein may provide at least about an additional 10dB of attenuation.
Figure 83 is a schematic diagram of a BAW resonator filter including a BAW resonator bandpass filter lattice 6401 including a first parallel bandstop resonator 8310 and a second parallel bandstop resonator 8315 shown in figure 64A in accordance with some embodiments of the invention. Figure 84 is a schematic diagram of a BAW resonator filter including a BAW resonator bandpass filter lattice 6402, including a first parallel bandstop resonator 8410 and a second parallel bandstop resonator 8415, as shown in figure 64B, in accordance with some embodiments of the present invention. According to fig. 83 and 84, a first parallel band-stop resonator and a second parallel band-stop resonator may also be added to the input node and the output node of the BAW resonator band-pass filter lattice, respectively, as shown in fig. 64A and 64B, to further improve the stop-band performance.
Fig. 85 is a graph illustrating a BAW resonator filter response 8524 including the resonant frequencies of the first parallel band-stop resonator 8310/8410 and the second parallel band-stop resonator 8315/8415 shown in fig. 83 and 84 in some embodiments of the invention. According to fig. 85, the resonant frequency peaks 7805 and 7806 associated with the first parallel band-stop resonator 8310/8410 and the second parallel band-stop resonator 8315/8415 may be approximately aligned with the suppression zeros 7807 and 7808 in the stopband below the upper passband of the BAW resonator filter response 8524. It should be appreciated that while the suppression zeros 7807 and 7808 in fig. 85 are above the pass band, in some embodiments, the corresponding suppression zeros may be near above the upper edge of the pass band. As understood by the present inventors, the alignment of the resonant frequency peaks from the first parallel band-stop resonator 8310/8410 and the second parallel band-stop resonator 8315/8415 with the reject zeros 8707 and 8708 may provide a combined attenuation in the rejection band that is higher than would be provided without the inclusion of the first parallel band-stop resonator 8310/8410 and the second parallel band-stop resonator 8315/8415. In some embodiments, including parallel band-stop resonators 8310/8410 and 8315/8415 that achieve the alignment described herein may provide at least about an additional 5dB of attenuation compared to not including the first parallel band-stop resonator 8310/8410 and the second parallel band-stop resonator 8315/8415. In some embodiments, including parallel band-stop resonators 8310/8315 and 8410/8415 that achieve the alignment described herein can provide at least about an additional 10dB of attenuation.
Fig. 79 is a schematic diagram of a combined BAW resonator filter 7900 including a BAW resonator bandpass filter ladder 7505 coupled to first and second series bandstop resonators and a BAW resonator bandpass filter ladder 7705 coupled to first and second parallel bandstop resonators. The inputs and outputs of BAW resonator bandpass filter ladder 7505 and BAW resonator bandpass filter ladder 7705 are controlled by setting switch 7905/7910 according to some embodiments of the invention. According to fig. 79, in a first state switch 7905/7910 may couple an input signal to BAW resonator bandpass filter ladder 7505 via an input series band-stop resonator and the output of BAW resonator bandpass filter ladder 7505 to an output signal of BAW resonator filter 7900 via an output series band-stop resonator, while in a second state switch 7905/7910 may couple an input signal to BAW resonator bandpass filter ladder 7705 via an input parallel band-stop resonator and the output of BAW resonator bandpass filter ladder 7705 to an output signal of BAW resonator filter 7900 via an output parallel band-stop resonator. Although the combined BAW resonator filter 7900 in fig. 79 shows a first ladder filter circuit topology and a second ladder filter circuit topology, it should be understood that any topology filter circuit, such as a lattice or modified lattice, may be used in accordance with some embodiments of the present invention. Also, in some embodiments, a combination of ladder filter circuits and lattice filter circuits may be included in BAW resonator filter 7900. Also, more than two filter circuits and a plurality of switches configured to operate to select a filter to be used may be included in BAW resonator filter 7900.
While the above is a complete description of the specific embodiments, various modifications, alternative constructions, and equivalents may be used. For example, the packaged device may include any combination of elements described above and outside of this specification. Accordingly, the above summary and drawings should not be considered to limit the scope of the invention as defined in the appended claims.
Claims (33)
1. A Bulk Acoustic Wave (BAW) resonator filter, comprising:
a BAW resonator bandpass filter circuit configured to pass frequency components of a passband input signal received at an input node of the BAW resonator bandpass filter circuit to an output node of the BAW resonator bandpass filter circuit;
a first series bandstop resonator coupled in series between the input port of the BAW resonator bandpass filter circuit and the input node, the first series bandstop resonator having a first antiresonant frequency peak in a bandstop below the passband; and
a second series band-stop resonator coupled in series between an output port of the BAW resonator filter and the output node, the second series band-stop resonator having a second anti-resonant frequency peak in the rejection band.
2. The BAW resonator filter of claim 1, wherein the BAW resonator bandpass filter circuit comprises a ladder topology, a lattice topology, or a modified lattice topology.
3. The BAW resonator filter of claim 2, wherein the BAW resonator bandpass filter circuit comprises a BAW resonator bandpass filter ladder comprising:
a plurality of series bandpass resonators coupled in series between the input node and the output node, the series bandpass resonators having respective resonant frequency peaks in the passband; and
a plurality of parallel bandpass resonators of the BAW resonator filter coupled in parallel with the input node and a reference node or coupled in parallel with the output node and a reference node, the parallel bandpass resonators having respective anti-resonant frequency peaks in the passband.
4. The BAW resonator filter of claim 3, wherein a peak resonant frequency of each of the series bandpass resonators and a peak anti-resonant frequency of each of the parallel bandpass resonators are approximately centered at the passband.
5. The BAW resonator filter of claim 4, wherein the parallel bandpass resonators each have a peak resonant frequency at or below about a lower edge of the passband, and the series bandpass resonators each have a peak anti-resonant frequency at or above about an upper edge of the passband.
6. The BAW resonator filter of claim 1, wherein the passband is about 5.49GHz to about 5.835 GHz.
7. The BAW resonator filter of claim 6, wherein the stopband is about 5.17GHz to about 5.33 GHz.
8. The BAW resonator filter of claim 1, wherein the BAW resonator bandpass filter circuit provides a first and second rejection zero in a rejection band adjacent a lower edge of the pass band; and is
Wherein the first and second anti-resonant frequency peaks of the first and second series band-stop resonators are approximately aligned with the first and second rejection zeroes at the respective frequencies to provide combined attenuation of the bandstop input signal at the respective frequencies.
9. The BAW resonator filter of claim 8, wherein the first anti-resonance frequency peak and the second anti-resonance frequency peak provide at least about an additional 5dB of attenuation of the combined attenuation.
10. The BAW resonator filter of claim 1, wherein the first series bandstop resonator comprises a first stopband mass loading structure having a mass greater than a passband mass loading structure on a parallel bandpass resonator included in the BAW resonator bandpass filter circuit.
11. The BAW resonator filter of claim 10, wherein the second series band-stop resonator comprises a second stop-band mass loading structure having a mass greater than a pass-band mass loading structure on a parallel band-pass resonator included in the BAW resonator band-pass filter circuit.
12. The BAW resonator filter of claim 1, wherein the first anti-resonance frequency peak and the second anti-resonance frequency peak are in a range of about 5.17GHz to about 5.33 GHz.
13. A Bulk Acoustic Wave (BAW) resonator filter, comprising:
a BAW resonator bandpass filter circuit configured to pass frequency components of a passband input signal received at an input port of the BAW resonator bandpass filter circuit to an output port of the BAW resonator bandpass filter circuit;
a first parallel bandstop resonator coupled in parallel between an input port of the BAW resonator bandpass filter circuit and a reference node of the BAW resonator bandpass filter circuit, the first parallel bandstop resonator having a first resonant frequency peak in a bandstop band above the passband; and
a second parallel band-stop resonator coupled in parallel between an output port of the BAW resonator filter and the reference node, the second parallel band-stop resonator having a second resonant frequency peak in the rejection band.
14. The BAW resonator filter of claim 13, wherein the BAW resonator bandpass filter circuit comprises a ladder topology, a lattice topology, or a modified lattice topology.
15. The BAW resonator filter of claim 14, wherein the BAW resonator bandpass filter circuit comprises a BAW resonator bandpass filter ladder comprising:
a plurality of series bandpass resonators coupled in series between the input port and the output port, the series bandpass resonators having respective resonant frequency peaks in the passband; and
a plurality of parallel bandpass resonators of the BAW resonator filter coupled in parallel with the input port and a reference node or coupled in parallel with the output port and a reference node, the parallel bandpass resonators having respective anti-resonant frequency peaks in the passband.
16. The BAW resonator filter of claim 15, wherein the respective resonant frequency peaks of the series bandpass resonators and the respective anti-resonant frequency peaks of the parallel bandpass resonators are approximately at the center of the passband.
17. The BAW resonator filter of claim 16, wherein the parallel bandpass resonators each have a peak resonant frequency at or below about a lower edge of the passband, and the series bandpass resonators each have a peak anti-resonant frequency at or above about an upper edge of the passband.
18. The BAW resonator filter of claim 13, wherein the passband is about 5.17GHz to about 5.33 GHz.
19. The BAW resonator filter of claim 18, wherein the stopband is about 5.49GHz to about 5.835 GHz.
20. The BAW resonator filter of claim 13, wherein the BAW resonator bandpass filter circuit provides a first and second rejection zero in a rejection band adjacent an upper edge of the pass band; and is
Wherein the first and second resonant frequency peaks of the first and second parallel band-stop resonators are approximately aligned with the first and second rejection zeroes at the respective frequencies to provide combined attenuation of the bandstop input signal at the respective frequencies.
21. The BAW resonator filter of claim 20, wherein the first resonant frequency peak and the second resonant frequency peak provide at least about an additional 5dB of attenuation of the combined attenuation.
22. The BAW resonator filter of claim 13, wherein the first parallel band-pass resonator comprises a first stop-band mass loading structure having a mass less than a pass-band mass loading structure on a series-band resonator included in the BAW resonator band-pass filter circuit.
23. The BAW resonator filter of claim 22, wherein the second parallel band-stop resonator comprises a second stop-band mass loading structure having a mass less than a pass-band mass loading structure on a series-band resonator included in the BAW resonator band-pass filter circuit.
24. The BAW resonator filter of claim 13, wherein the first resonant frequency peak and the second resonant frequency peak are in a range from about 5.49GHz to about 5.835 GHz.
25. A Bulk Acoustic Wave (BAW) resonator filter, comprising:
a BAW resonator bandpass filter circuit configured to pass frequency components of a passband input signal received at an input node of the BAW resonator bandpass filter circuit to an output node of the BAW resonator bandpass filter circuit; and
a first series bandstop resonator coupled in series with an input port of the BAW resonator bandpass filter circuit or an output port of the BAW resonator bandpass filter circuit, the first series bandstop resonator having a first antiresonant frequency peak in a stopband below the passband.
26. The BAW resonator filter of claim 25, wherein the BAW resonator bandpass filter circuit comprises a ladder topology, a lattice topology, or a modified lattice topology.
27. The BAW resonator filter of claim 26, wherein the BAW resonator bandpass filter circuit comprises a BAW resonator bandpass filter ladder, the first series bandstop resonator is coupled in series between the input port of the BAW resonator bandpass filter circuit and the input node, and the BAW resonator filter further comprises:
a second series band-stop resonator coupled in series between an output port of the BAW resonator band-pass filter circuit and the output node, the second series band-stop resonator having a second anti-resonant frequency peak in the rejection band.
28. A Bulk Acoustic Wave (BAW) resonator filter, comprising:
a BAW resonator bandpass filter circuit configured to pass frequency components of a passband input signal received at an input port of the BAW resonator bandpass filter circuit to an output port of the BAW resonator bandpass filter circuit; and
a first parallel band-stop resonator coupled in parallel between an input port of the BAW resonator band-pass filter circuit and a reference node of the BAW resonator band-pass filter circuit or between an output port of the BAW resonator band-pass filter circuit and the reference node, the first parallel band-stop resonator having a first resonant frequency peak in a stop band above the pass band.
29. The BAW resonator filter of claim 28, wherein the BAW resonator bandpass filter circuit comprises a ladder topology, a lattice topology, or a modified lattice topology.
30. The BAW resonator filter of claim 29, wherein the BAW resonator bandpass filter circuit comprises a BAW resonator bandpass filter ladder, the first parallel bandstop resonator is coupled in parallel between the input port of the BAW resonator bandpass filter circuit and the reference node, and the BAW resonator filter further comprises:
a second parallel band-stop resonator coupled in parallel between an output port of the BAW resonator band-pass filter circuit and the reference node, the second parallel band-stop resonator having a second resonant frequency peak in the rejection band.
31. A Bulk Acoustic Wave (BAW) resonator filter, comprising:
a first BAW resonator bandpass filter circuit configured to pass frequency components of an input signal in a first passband of a BAW resonator filter received at an input port of the first BAW resonator bandpass filter circuit to an output port of the first BAW resonator bandpass filter circuit;
a first series bandstop resonator coupled in series with an input port of the first BAW resonator bandpass filter circuit or an output port of the first BAW resonator bandpass filter circuit, the first series bandstop resonator having a first antiresonant frequency peak in a first stopband below the first passband;
a second BAW resonator bandpass filter circuit configured to pass frequency components of a second passband input signal received at an input port of the second BAW resonator bandpass filter circuit to an output port of the second BAW resonator bandpass filter circuit;
a first parallel bandstop resonator coupled in parallel between an input port of the second BAW resonator bandpass filter circuit and a reference node of the second BAW resonator bandpass filter circuit or between an output port of the second BAW resonator bandpass filter circuit and a reference node of the second BAW resonator bandpass filter circuit, the first parallel bandstop resonator having a first resonant frequency peak in a second bandstop higher than the second passband; and
a switch configured in a first state to couple the input signal to the input port of the first BAW resonator bandpass filter circuit and to couple the output port of the first BAW resonator bandpass filter circuit to the output signal of the BAW resonator filter, and configured in a second state to couple the input signal to the input port of the second BAW resonator bandpass filter circuit and to couple the output port of the second BAW resonator bandpass filter circuit to the output signal of the BAW resonator filter.
32. The BAW resonator filter of claim 31, wherein in the first state, the first passband is about 5.49GHz to about 5.835GHz, and wherein the first stopband is about 5.17GHz to about 5.33 GHz.
33. The BAW resonator filter of claim 31, wherein in the second state, the second passband is about 5.17GHz to about 5.33GHz, and wherein the second stopband is about 5.49GHz to about 5.835 GHz.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US201962885047P | 2019-08-09 | 2019-08-09 | |
| US62/885,047 | 2019-08-09 | ||
| US16/660,227 US10873317B2 (en) | 2016-03-11 | 2019-10-22 | Bulk acoustic wave resonator filters including rejection-band resonators |
| US16/660,227 | 2019-10-22 | ||
| PCT/US2020/040985 WO2020227729A1 (en) | 2019-05-08 | 2020-07-07 | Bulk acoustic wave resonator filters including rejection-band resonators |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114026786A true CN114026786A (en) | 2022-02-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202080034291.XA Pending CN114026786A (en) | 2019-08-09 | 2020-07-07 | BAW resonator filter comprising band-stop resonators |
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| KR (1) | KR20220034037A (en) |
| CN (1) | CN114026786A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20210273630A1 (en) * | 2020-05-18 | 2021-09-02 | Akoustis, Inc. | Bulk acoustic wave resonator filters including a high impedance shunt branch and methods of forming the same |
-
2020
- 2020-07-07 CN CN202080034291.XA patent/CN114026786A/en active Pending
- 2020-07-07 KR KR1020217040262A patent/KR20220034037A/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20210273630A1 (en) * | 2020-05-18 | 2021-09-02 | Akoustis, Inc. | Bulk acoustic wave resonator filters including a high impedance shunt branch and methods of forming the same |
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| KR20220034037A (en) | 2022-03-17 |
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