Bulk acoustic wave component and method for plasma cutting the bulk acoustic wave component

Abstract

Aspects of the present disclosure relate to methods of fabricating bulk acoustic wave components. Such methods include plasma cutting to singulate individual bulk acoustic wave components. A buffer layer may be formed over a substrate of the bulk acoustic wave component such that a block is exposed. The bulk acoustic wave component may be plasma cut along the exposed block to singulate the bulk acoustic wave component. Related bulk acoustic wave components are disclosed.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of priority of U.S. Provisional Patent Application No. 62 / 747,486, filed on October 18, 2018, entitled "BULK ACOUSTIC WAVE COMPONENTS AND METHODS OF PLASMA DICING THE SAME", the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] Embodiments of the present application relate to acoustic wave components, and more particularly, to bulk acoustic wave components. Background Art

[0004] Acoustic wave filters can be implemented in radio frequency (RF) electronic systems. For example, filters in the RF front - end of a mobile phone can include acoustic wave filters. Acoustic wave filters can filter RF signals. Acoustic wave filters can be band - pass filters. Multiple acoustic wave filters can be arranged as a multiplexer. For example, two acoustic wave filters can be arranged as a duplexer.

[0005] Acoustic wave filters can include multiple acoustic wave resonators arranged to filter RF signals. Example acoustic wave filters include surface acoustic wave (SAW) filters and bulk acoustic wave (BAW) filters. BAW filters include BAW resonators. Example BAW resonators include film bulk acoustic wave resonators (FBAR) and solidly mounted resonators (SMR). In a BAW resonator, acoustic waves propagate in the bulk of a piezoelectric layer.

[0006] BAW components can include encapsulated BAW resonators enclosed within a sealed portion. The encapsulation structure increases the size of the BAW component. It is desirable to reduce the size of the BAW component without sacrificing reliability and performance. Summary of the Invention

[0007] Each innovation described in the claims has several aspects, and no single aspect is solely responsible for its desirable attributes. Without limiting the scope of the claims, some of the notable features of the present application will now be briefly described.

[0008] One aspect of the present application is a method for manufacturing a monolithic bulk acoustic wave component. The method includes forming a buffer layer above a substrate of an array of bulk acoustic wave components to form an exposed street between individual bulk acoustic wave components. The method further includes plasma cutting the bulk acoustic wave components along the exposed street, thereby monolithicizing the bulk acoustic wave components.

[0009] Each monolithic bulk acoustic wave component may include a bulk acoustic wave resonator and a cover enclosing the bulk acoustic wave resonator. The cover may include sidewalls that are 5 micrometers or less from an edge of a substrate of the corresponding monolithic bulk acoustic wave component. The sidewalls may be at least 1 micrometer from an edge of the corresponding monolithic bulk acoustic wave component. The sidewalls may include copper.

[0010] Plasma cutting may include etching through both the substrate and the cover substrate. The bulk acoustic wave component may include a bulk acoustic wave resonator located above the substrate and below the cover substrate. The substrate and the cover substrate may be silicon substrates.

[0011] The method may further include forming a conductor above the substrate. The conductor may extend laterally from a via hole extending through the substrate. The conductor may be electrically connected to a conductive layer in the via hole. The buffer layer may be formed such that the buffer layer is above at least a portion of the conductor. The method may further include forming solder above the conductor such that the solder does not overlap the via hole.

[0012] The substrate may be a silicon substrate. The buffer layer may be a material that is at least 30 times slower to etch than silicon during plasma cutting. The buffer layer may include a resin. Forming the buffer layer may include forming the exposed street by means of a lithography process.

[0013] Each bulk acoustic wave component may include a thin film bulk acoustic wave resonator.

[0014] Another aspect of the present application is a method for manufacturing a bulk acoustic wave component. The method includes providing a first wafer bonded to a second wafer. The first wafer has a bulk acoustic wave resonator thereon. The second wafer is above and spaced apart from the bulk acoustic wave resonator. The method includes forming a buffer layer on a side of the first wafer opposite to the bulk acoustic wave resonator such that a street is exposed. The method includes plasma cutting through the first wafer and the second wafer along the exposed street to form monolithic bulk acoustic wave components.

[0015] The first wafer and the second wafer may be silicon wafers.

[0016] Each monolithic bulk acoustic wave component may include a bulk acoustic wave resonator in the bulk acoustic wave resonator and a cover enclosing the bulk acoustic wave resonator. The cover may include sidewalls. The sidewalls may be in a range of 1 micrometer to 5 micrometers from an edge of a substrate of the corresponding monolithic bulk acoustic wave component, where the substrate corresponds to a portion of the first wafer before plasma cutting.

[0017] Another aspect of the present application is a method of manufacturing a bulk acoustic wave component. The method includes forming a buffer layer above a silicon substrate of the bulk acoustic wave component such that a block is exposed. The method further includes plasma cutting the bulk acoustic wave component along the exposed block so as to singulate the bulk acoustic wave component. Each singulated bulk acoustic wave component includes a bulk acoustic wave resonator and a cover encapsulating the bulk acoustic wave resonator. The cover includes a silicon cover substrate and sidewalls that are spaced apart from an edge of the silicon substrate of the corresponding singulated bulk acoustic wave component by a distance in the range of 1 micron to 5 microns.

[0018] The sidewalls may include copper. The buffer layer may include a resin. The bulk acoustic wave resonator may be a thin film bulk acoustic wave resonator.

[0019] Another aspect of the present disclosure is a bulk acoustic wave component that includes a substrate, at least one bulk acoustic wave resonator on the substrate, and a cover encapsulating the at least one bulk acoustic wave resonator. The cover includes sidewalls that are spaced apart from an edge of the substrate. The sidewalls are 5 microns or less from the edge of the substrate.

[0020] The sidewalls may be 3 microns or less from the edge of the substrate. The sidewalls may be at least 1 micron from the edge of the substrate.

[0021] The bulk acoustic wave component may further include a through hole extending through the substrate, a conductive layer in the through hole, and a buffer layer in the through hole.

[0022] The bulk acoustic wave component may further include a through hole extending through the substrate, a conductor extending laterally from the through hole and electrically connected to the conductive layer in the through hole, and a solder on the conductor and positioned laterally from the through hole.

[0023] The at least one bulk acoustic wave resonator may include a thin film bulk acoustic wave resonator. The at least one bulk acoustic wave resonator may include a firmly mounted resonator.

[0024] The substrate may be a silicon substrate. The top of the cover may include a silicon cover substrate.

[0025] The sidewalls may include copper.

[0026] The at least one bulk acoustic wave resonator may include a plurality of bulk acoustic wave resonators included in a filter that is arranged to filter a radio frequency signal. The plurality of bulk acoustic wave resonators may include at least 10 bulk acoustic wave resonators.

[0027] Another aspect of the present application is a bulk acoustic wave component that includes a silicon substrate, at least one bulk acoustic wave resonator on the silicon substrate, and a cover encapsulating the at least one bulk acoustic wave resonator. The cover includes a cover substrate and sidewalls. The cover substrate includes silicon. The sidewalls are spaced apart from an edge of the silicon substrate by a distance in the range of 1 micron to 5 microns.

[0028] The bulk acoustic wave component may further include a through hole extending through the silicon substrate, a conductive layer in the through hole, and a buffer layer in the through hole.

[0029] The bulk acoustic wave component may further include a through hole extending through the substrate, a conductor extending laterally from the through hole and electrically connected to the conductive layer in the through hole, and a solder on the conductor and positioned laterally from the through hole.

[0030] The sidewall may include copper. The at least one bulk acoustic wave resonator may include at least 10 bulk acoustic wave resonators included in an acoustic wave filter, the filter being arranged to filter a radio frequency signal.

[0031] Another aspect of the present application is a wireless communication device including an antenna and a bulk acoustic wave component. The bulk acoustic wave component includes a substrate, a bulk acoustic wave resonator on the substrate, and a cover encapsulating the bulk acoustic wave resonator. The cover includes a sidewall spaced from the edge of the substrate by 5 microns or less. The bulk acoustic wave resonator is included in a filter in communication with the antenna.

[0032] The wireless communication device may be a mobile phone.

[0033] The wireless communication device may further include a radio frequency amplifier in communication with the filter and a switch coupled between the filter and the antenna.

[0034] To summarize the present disclosure, certain aspects, advantages, and novel features of the present application have been described herein. It should be understood that not all such advantages may be achieved in accordance with any particular embodiment. Thus, the present application may be implemented or carried out in a manner that realizes or optimizes one advantage or a group of advantages taught herein, without necessarily realizing other advantages taught or suggested herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Embodiments of the present disclosure will now be described with reference to the accompanying drawings by way of non-limiting examples.

[0036] Figure 1 is a flowchart of an example process for manufacturing a bulk acoustic wave component according to one embodiment.

[0037] Figures 2A to 2E is a cross-sectional view showing a process for manufacturing a bulk acoustic wave component according to one embodiment.

[0038] Figure 3A is a cross-sectional view of a bulk acoustic wave component according to one embodiment.

[0039] Figure 3B is a cross-sectional view of a bulk acoustic wave component according to another embodiment.

[0040] Figure 4 is a schematic diagram of a transmit filter including a bulk acoustic wave resonator of a bulk acoustic wave component according to one embodiment.

[0041] Figure 5 is a schematic diagram of a receive filter, which includes a bulk acoustic wave resonator of a bulk acoustic wave component according to an embodiment.

[0042] Figure 6 is a schematic diagram of a radio frequency system, which includes a bulk acoustic wave component according to an embodiment.

[0043] Figure 7 is a schematic diagram of a radio frequency module, which includes a bulk acoustic wave component according to an embodiment.

[0044] Figure 8 is a schematic diagram of a radio frequency module, which includes a bulk acoustic wave component according to an embodiment.

[0045] Figure 9A is a schematic block diagram of a wireless communication device, which includes a filter according to one or more embodiments.

[0046] Figure 9B is a schematic block diagram of another wireless communication device, which includes a filter according to one or more embodiments. Detailed Description

[0047] The following description of certain embodiments presents various descriptions of specific embodiments. However, the innovations described herein can be implemented in many different ways, for example, as defined and covered by the claims. In this description, reference is made to the accompanying drawings, in which like reference numerals may indicate identical or functionally similar elements. It will be understood that the elements illustrated in the drawings need not be drawn to scale. Additionally, it will be understood that some embodiments may include more elements than those illustrated in the drawings and / or a subset of the elements illustrated in the drawings. Further, some embodiments may incorporate any suitable combination of features from two or more of the drawings.

[0048] Acoustic wave filters can filter radiofrequency (RF) signals in a variety of applications, such as in the RF front-end of a mobile phone. Acoustic wave filters can include bulk acoustic wave (BAW) components. BAW components can include a single wafer. BAW components can include one or more BAW resonators on a substrate such as a silicon substrate. The one or more BAW resonators can be encapsulated by a lid of the BAW component. The lid can include another silicon substrate and sidewalls. The lid can form an airtight seal around the one or more BAW resonators. The sidewalls can include, for example, copper.

[0049] A BAW component can be manufactured by cutting bonded wafers having a hollow portion therebetween. Chipping occurs in a part of the BAW component facing the hollow portion. When there is a relatively large chipping, the hermetic seal around the BAW resonator will be broken. To reduce and / or eliminate the risk of chipping, the BAW component can include a space between the edge of the BAW component and the sealed portion. The space can be, for example, about 15 to 20 micrometers from the sidewall of the cover body to the cut edge of the BAW component. This space will occupy the area of the BAW component.

[0050] Aspects of the present application relate to a plasma cutting method for bulk acoustic wave components. A buffer layer can be formed over the bulk acoustic wave component to cover the re-wiring layer. The buffer layer can be formed such that the blocks for cutting are exposed. The buffer layer can be used as a mask layer for plasma cutting. The BAW component can be singulated by plasma cutting. Compared with other cutting techniques such as blade cutting or laser cutting, plasma cutting can reduce the chipping of the BAW component. Using plasma cutting, compared with other cutting techniques, the sidewall of the cover body enclosing one or more BAW resonators can be closer to the cut edge of the BAW component without increasing the risk of chipping of the BAW component. Plasma cutting can include cutting the upper wafer and the lower wafer across the hollow portion. The upper wafer and the lower wafer can be silicon wafers.

[0051] Using plasma cutting, the size of the BAW component can be reduced. Since the space between the sidewall of the cover body and the edge of the BAW component is smaller, more BAW components can be included on the wafer. In addition, the BAW component can occupy less area in the module.

[0052] Blade cutting techniques typically cut out sharp edges, and there may be lateral stress when cutting the chip with a blade. This can cause cracking and / or chipping at the sharp edges of the blade-cut component. Using plasma cutting, the pattern can be made by the lithography process for cutting, and there is no significant mechanical lateral stress during plasma cutting. Therefore, the sharp edge can be maintained by plasma cutting while reducing and / or eliminating the damage caused by mechanical fracture. In some cases, compared with mechanical fracture techniques, plasma cutting can result in a more rounded corner of the BAW component and a more reliable performance. The rounded corner can reduce and / or eliminate the risk of cracking and / or chipping of the BAW component.

[0053] Using the manufacturing techniques disclosed herein, in some cases, the yield of BAW components from a single wafer can be increased by about 10% to 18% compared with previous manufacturing methods. The increase in yield can reduce the manufacturing cost. Even if the cost increases due to additional processing operations and / or equipment investment, the manufacturing cost can still be reduced due to the increased yield.

[0054] A method of fabricating BAW components using plasma cutting is disclosed. Figure 1 FIG. 10 is a flow chart of an example process 10 for fabricating a bulk acoustic wave component according to one embodiment. The process 10 will be described with reference to Figures 2A to 2E the cross-sectional views illustrated. Any method discussed herein may include more or fewer operations and the operations may be performed in any suitable order.

[0055] Process 10 includes providing, at block 12, one or more BAW resonators encapsulated within a lid on a substrate. The substrate may be a silicon substrate. The lid may include sidewalls and a second substrate that together encapsulate the one or more BAW resonators. The second substrate may be a silicon substrate. The one or more BAW resonators may include film bulk acoustic wave resonators (FBARs) and / or solidly mounted resonators (SMRs).

[0056] At block 14, a redistribution layer is formed over the substrate. The redistribution layer includes conductors that extend laterally from vias through the substrate. The redistribution layer may be referred to as a wiring layer. The redistribution layer may be formed during the same processing operations as forming a conductive layer in one or more vias through the substrate of the BAW component. The redistribution layer and the conductive layer may be, for example, about 5 microns thick. Solder may be formed over a portion of the redistribution layer. The redistribution layer may provide an electrical connection from the conductive layer in the via through the substrate to the solder of the BAW component. Using the redistribution layer, solder may be formed over any suitable portion of the substrate. For example, the solder may be formed laterally from the via through the substrate. In some cases, the solder and the via through the substrate do not overlap.

[0057] Figure 2A FIG. 11 illustrates a cross-section of a plurality of BAW components having a redistribution layer formed at block 14 of process 10. As Figure 2A illustrated, the plurality of BAW components have not been monolithically integrated. Figure 2A FIG. 12 illustrates a lid substrate 21, a substrate 22, sidewalls 23, BAW resonators 24, air cavities 25, vias through the substrate 26, conductive layers 27 in the respective vias through the substrate 26, a redistribution layer 28, and electrodes 29. Prior to monolithically integrating individual BAW components, a first wafer includes a substrate 22 for each of the individual BAW components and a second wafer includes a lid substrate 21 for each of the individual BAW components. As shown, the first wafer is bonded to the second wafer.

[0058] The BAW resonator 24 is encapsulated within a lid that includes a lid substrate 21 and sidewalls 23. The BAW resonator 24 is encapsulated within the lid before the redistribution layer 28 is formed. As shown, a bonding layer 30 and a lid layer 31 may be located between the substrate 22 and the sidewalls 23. The bonding layer 30 may be a gold layer. The lid layer 31 may be a tin lid layer. The lid forms an airtight seal around the BAW resonator 24. Thus, an air cavity 25 may be included within the lid around the BAW resonator 24. In some cases, the BAW component may include from 10 to 50 BAW resonators 24 encapsulated within the lid. The BAW resonator 24 may include one or more FBARs. Alternatively or additionally, the BAW resonator 24 may include one or more SMRs. The BAW resonator 24 may be included in one or more filters. The substrate 21 may be a silicon substrate. The sidewalls 23 may include copper.

[0059] The BAW resonator 24 is on the substrate 22 and is encapsulated by the lid. The substrate 22 may be a silicon substrate. The conductive layer 27 within the through-substrate via 26 may provide electrical connection from one or more BAW resonators 24 to components on the opposite side of the substrate 22. As shown, the redistribution layer 28 formed at block 14 is above the substrate 22 and extends laterally from the through-substrate via 26. Thus, the electrode 29 may be formed laterally above the redistribution layer 28 from the through-substrate via 26. The redistribution layer 28 is on the side of the substrate 22 opposite the BAW resonator 24. The electrode 29 provides a terminal for external connection for the BAW component. Using the redistribution layer 28, the electrode 29 may be positioned at any suitable location of the BAW component. The redistribution layer 28 may provide shielding. The redistribution layer 28 may shield the BAW resonator 24 from external components and / or shield external components from the BAW resonator 24.

[0060] Return reference Figure 1 , at block 16, a buffer layer is formed above the substrate such that the blocks are exposed. The buffer layer may be formed by means of a lithography process. Forming the buffer layer may include depositing a layer of buffer material, masking certain regions above the buffer material, and applying light to remove the buffer material above the blocks. The surface of the substrate may be exposed along the blocks. The buffer layer may provide encapsulation of the BAW component on the side opposite the lid substrate. The buffer layer may be formed above the redistribution layer that may be formed at block 14.

[0061] Figure 2B A cross-section of a BAW component including the buffer layer 32 formed at block 16 of process 10 is illustrated. The buffer layer 32 is above the substrate 22. The buffer layer 32 is on the side of the substrate 22 opposite the BAW resonator 24. A portion of the buffer layer 32 is within the through-substrate via 26. The buffer layer 32 is also above portions of the redistribution layer 28. As Figure 2BAs shown, a buffer layer 32 is formed to keep the electrode 29 exposed. The buffer layer 32 includes a material that serves as a mask to resist etching during plasma cutting of the substrate 22. For example, the buffer layer 32 can be a material that is etched less than silicon when silicon etching is performed on the substrate 22, which is a silicon substrate. Generally, the etching rate of the buffer layer 32 is more than 30 times slower than that of silicon. Therefore, a typical buffer layer thickness is sufficient for plasma cutting of wafers. The buffer layer 32 can be a polyimide layer, a phenolic resin layer such as a phenolic resin layer with rubber fillers, or any other suitable buffer layer. The block 34 facilitates the cutting of the BAW component.

[0062] Figure 2C is illustrated Figure 2B An enlarged view of a part 35 of the BAW component illustrated in. As shown, the block 34 can have a width D S . As shown, the width D S is suitable for plasma cutting. The width D of the block 34 S can be in the range of about 10 microns to 20 microns, for example, in the range of 10 microns to 15 microns. As an example, the width D of the block 34 S can be about 15 microns. Figure 2C It is also illustrated that a bonding layer 30 and a cover layer 31 can be included between the substrate 22 and the sidewall 23.

[0063] Returning to reference Figure 1 , at block 18, the BAW component is plasma cut along the exposed blocks. This singulates the BAW component. In other words, the BAW components are separated from each other into individual BAW components by plasma cutting. The plasma cutting can include dry etching through the substrate on which the BAW resonator is disposed and through the cover substrate. During this etching, there can be a hollow portion (e.g., as Figure 2B shown) between the substrate and the cover substrate under the block. As an example, both the substrate and the cover substrate can be silicon substrates, which are etched at a rate of about 20 microns per minute. In this example, the substrate and the cover substrate together can be about 200 microns thick, and it may take about 10 minutes to etch through about 200 microns of silicon. Using plasma cutting, the fragmentation of singulated BAW components can be reduced compared to other cutting methods such as blade cutting or laser cutting. For plasma cutting, the lithography process can make any pattern suitable for the blocks. In some cases, this may result in rounded corners of the singulated BAW components. Such rounded corners can reduce the risk of cracking and / or fragmentation of the BAW components, thereby increasing the reliability of the BAW components.

[0064] Figure 2DIllustrated is a cross-section of a BAW component after plasma cutting at block 18 of process 10. Plasma cutting along the streets can remove portions of the substrate 22 and the cover substrate 21, thereby separating the individual BAW components. Figure 2D A plurality of singulated BAW components 36 are shown in

[0065] Figure 2E Illustrated is Figure 2D an enlarged view of a portion 38 of the singulated BAW component 36 illustrated in E . As shown, the distance D from the sidewall 23 of the singulated BAW component 36 to the edge of the substrate 22 is E relatively small. Using a buffer layer as a mask for plasma cutting, a lithography process can be used. Thus, plasma cutting has a higher precision than other cutting methods such as blade cutting or laser cutting with mechanical system precision. For example, plasma cutting can be performed within a precision of + / - 2 microns. However, in the case of blade cutting, the mechanical precision is + / - 10 microns, and there may be chipping of 5 to 10 microns. For plasma cutting, as the precision increases and the risk of chipping decreases, the distance D from the sidewall 23 of the singulated BAW component 36 to the edge of the substrate 22 can be reduced E . The distance D from the sidewall 23 of the singulated BAW component 36 to the edge of the substrate 22 E can be less than 5 microns. The distance D E can be less than 3 microns. As an example, the distance D E can be about 2.5 microns. As shown, the distance D E is greater than zero. In some cases, the distance D

[0066] can be in the range of 1 micron to 5 microns, for example in the range of 1 micron to 3 microns. In certain cases, the sidewall 23 and the edge of the substrate 22 can be substantially flush in the singulated BAW component. SW Thus, using plasma cutting, the space between the respective sidewalls 23 of adjacent BAW components on the wafer can be small. The distance D from the sidewall 23 of each adjacent singulated BAW component Figure 2E corresponds to S the sum of the street width D E in SW and twice the distance D SW . The distance D S can be in the range of about 10 microns to 30 microns, for example. In certain cases, the distance D Ecan be about 2.5 microns, which will result in a distance D SW in Figure 2E the illustrated cross-section being about 20 microns.

[0067] Figure 3A is a cross-sectional view of a bulk acoustic wave component 40 according to an embodiment. The BAW component 40 can be manufactured by a process including plasma cutting. For example, the bulk acoustic wave component 40 can correspond to a monolithic BAW component manufactured by process 10 of Figure 1 the process 10.

[0068] As Figure 3A shown, as a result of plasma cutting, the distance D from the sidewall 23 to the edge of the substrate 22 of the monolithic BAW component 36 E can be relatively small. The distance D E can be within any of the ranges and / or have any of the values disclosed herein, such as the ranges and values described with reference to Figure 2E the process 10. In the illustrated BAW component 40, the BAW resonator 24 is encapsulated within a cap including a cap substrate 21 and a sidewall 23. The BAW resonator 24 can form some or all of the resonators of one or more acoustic wave filters. Any suitable number of BAW resonators 24 can be encapsulated within the cap of the BAW component 40. For example, 10 to 50 BAW resonators 24 can be encapsulated within the cap of the BAW component 40. The BAW resonator 24 can be electrically connected to the electrode 29 by means of a conductive layer 27 and a rewiring layer 28 in the through-substrate via 26. A buffer layer 32 extends above the rewiring layer 28 and is included in the through-substrate via 26 of the BAW component.

[0069] Figure 3B is a cross-sectional view of a bulk acoustic wave component 42 according to an embodiment. The BAW component 42 can be manufactured by a process including plasma cutting. For example, the bulk acoustic wave component 42 can correspond to a monolithic BAW component manufactured by process 10 of Figure 1 the process 10. Except that the BAW component 42 includes a via 26, the BAW component 42 is the same as Figure 3A the BAW component 40, where the via 26 is filled with a conformal conductive layer 43 instead of the conductive layer 27. The conformal conductive layer 43 can be, for example, a copper layer. The bulk acoustic wave component 42 illustrates that the via 26 can be filled with a conformal layer 43.

[0070] One or more bulk acoustic wave resonators of a bulk acoustic wave component including any suitable combination of features disclosed herein are included in a filter arranged to filter radio frequency signals in a fifth generation (5G) New Radio (NR) operating band within a frequency range 1 (FR1). A filter arranged to filter radio frequency signals in a 5G NR operating band may include one or more acoustic wave resonators of any bulk acoustic wave component disclosed herein. For example, as specified in current 5G NR specifications, FR1 may be from 410 megahertz (MHz) to 7.125 gigahertz (GHz). One or more bulk acoustic wave resonators of a bulk acoustic wave component according to any suitable principles and advantages disclosed herein may be included in a filter arranged to filter radio frequency signals in a fourth generation (4G) Long Term Evolution (LTE) operating band and / or having a passband spanning at least one 4G LTE operating band and at least one 5G NR operating band.

[0071] Figure 4 is a schematic diagram of a transmit filter 45 that includes a bulk acoustic wave resonator of a bulk acoustic wave component according to one embodiment. The transmit filter 45 may be a bandpass filter. The illustrated transmit filter 45 is arranged to filter radio frequency signals received at a transmit port TX and provide a filtered output signal to an antenna port ANT. The transmit filter 45 includes series BAW resonators TS1, TS2, TS3, TS4, TS5, TS6, and TS7, shunt BAW resonators TP1, TP2, TP3, TP4, and TP5, a series input inductor L1, and a shunt inductor L2. Some or all of the BAW resonators TS1 through TS7 and / or TP1 through TP5 may be included in a BAW component according to any suitable principles and advantages disclosed herein. For example, Figure 3A of the BAW component 40 or Figure 3B of the BAW component 42 may include all of the BAW resonators of the transmit filter 45. In some cases, a BAW component according to any suitable principles and advantages disclosed herein may include BAW resonators of two or more acoustic wave filters. Any suitable number of series BAW resonators and shunt BAW resonators may be included in the transmit filter 45.

[0072] Figure 5FIG. 0 is a schematic diagram of a receive filter 50 that includes a bulk acoustic wave resonator of a bulk acoustic wave component according to one embodiment. The receive filter 50 can be a bandpass filter. The illustrated receive filter 50 is arranged to filter a radio frequency signal received at an antenna port ANT and provide a filtered output signal to a receive port RX. The receive filter 50 includes series BAW resonators RS1, RS2, RS3, RS4, RS5, RS6, RS7, and RS7, shunt BAW resonators RP1, RP2, RP3, RP4, RP5, and RP6, a shunt inductor L2, and a series output inductor L3. Some or all of the BAW resonators RS1 to RS8 and / or RP1 to RP6 can be included in a BAW component according to any suitable principles and advantages disclosed herein. For example, Figure 3A the BAW component 40 of Figure 3B or the BAW component 42 of

[0073] Figure 6 FIG. 8 is a schematic diagram of a radio frequency system 60 that includes a bulk acoustic wave component according to one embodiment. As shown, the radio frequency system 60 includes an antenna 62, an antenna switch 64, multiplexers 65 and 66, filters 67 and 68, power amplifiers 70, 72, and 74, and a selection switch 73. The power amplifiers 70, 72, and 74 are respectively arranged to amplify radio frequency signals. The selection switch 73 can electrically connect the output of the power amplifier 72 to a selected filter. One or more filters of the multiplexer 65 and / or the multiplexer 66 can include one or more BAW resonators of a BAW component according to any suitable principles and advantages discussed herein. In some cases, the BAW component can include one or more filters of one multiplexer. Although Figure 6 the multiplexer illustrated in

[0074] The BAW components discussed herein can be implemented in various packaging modules. These BAW components consume less area in the packaging module compared to similar modules cut using laser cutting. A packaging module configured to handle radio frequency signals can be referred to as a radio frequency module. Some radio frequency modules are front-end modules. A radio frequency module including BAW components according to any suitable principles and advantages disclosed herein may also include one or more radio frequency amplifiers (e.g., one or more power amplifiers and / or one or more low noise amplifiers), one or more radio frequency switches, etc., or any suitable combination thereof. Example packaging modules will now be discussed, in which any suitable principles and advantages of the BAW components discussed herein can be implemented. Figure 7 and Figure 8 is a schematic block diagram of an illustrative packaging module according to certain embodiments. Any suitable combination of the features of these embodiments can be combined with each other.

[0075] Figure 7 is a schematic diagram of a radio frequency module 75 that includes a bulk acoustic wave component 76 according to one embodiment. The illustrated radio frequency module 75 includes a BAW component 76 and other circuitry 77. The BAW component 76 can include any suitable combination of the features of the BAW components disclosed herein. The BAW component 76 can include a BAW wafer that includes BAW resonators.

[0076] Figure 7 The shown BAW component 76 includes a filter 78 and terminals 79A and 79B. The filter 78 includes BAW resonators. The terminals 79A and 78B can be used as, for example, input contacts and output contacts. The BAW component 76 and other circuitry 77 are on Figure 7 a common packaging substrate 80. The packaging substrate 80 can be a laminated substrate. The terminals 79A and 79B can be electrically connected to contacts 81A and 81B on the packaging substrate 80 by means of electrical connectors 82A and 82B, respectively. The electrical connectors 82A and 82B can be, for example, bumps or wire bonds. The other circuitry 77 can include any suitable additional circuitry. For example, the other circuitry can include one or more power amplifiers, one or more radio frequency switches, one or more additional filters, one or more low noise amplifiers, etc., or any suitable combination thereof. The radio frequency module 75 can include one or more packaging structures to, for example, provide protection to the radio frequency module 75 and / or facilitate easier operation of the radio frequency module 75. Such a packaging structure can include an overmold structure formed above the packaging substrate 75. The overmold structure can overmold some or all of the components of the radio frequency module 75.

[0077] Figure 8It is a schematic diagram of the radio frequency module 84, which includes a bulk acoustic wave component according to an embodiment. As shown, the radio frequency module 84 includes duplexers 85A to 85N, which include respective transmit filters 86A1 to 86N1 and respective receive filters 86A2 to 86N2, a power amplifier 87, a selection switch 88, and an antenna switch 89. The radio frequency module 84 may include a package enclosing the illustrated components. The illustrated components may be disposed on a common package substrate 80. The package substrate may be, for example, a laminated substrate.

[0078] Each of the duplexers 85A to 85N may include two acoustic wave filters coupled to a common node. The two acoustic wave filters may be a transmit filter and a receive filter. As shown, the transmit filter and the receive filter may be band-pass filters configured to filter radio frequency signals, respectively. According to any suitable principles and advantages disclosed herein, one or more of the transmit filters 86A1 to 86N1 may include one or more BAW resonators of a BAW component according to any suitable principles and advantages disclosed herein. Similarly, one or more of the receive filters 86A2 to 86N2 may include one or more BAW resonators of a BAW component according to any suitable principles and advantages disclosed herein. Although Figure 8 duplexers are illustrated, any suitable principles and advantages disclosed herein may be implemented in other multiplexers (e.g., quadplexers, hexaplexers, octaplexers, etc.) and / or switched multiplexers.

[0079] The power amplifier 87 may amplify radio frequency signals. The illustrated switch 88 is a multi-throw radio frequency switch. The switch 88 may electrically couple the output of the power amplifier 87 to a selected transmit filter among the transmit filters 86A1 to 86N1. In some cases, the switch 88 may electrically connect the output of the power amplifier 87 to more than one of the transmit filters 86A1 to 86N1. The antenna switch 89 may selectively couple signals from one or more of the duplexers 85A to 85N to the antenna port ANT. The duplexers 85A to 85N may be associated with different frequency bands and / or different operating modes (e.g., different power modes, different signaling modes, etc.).

[0080] Figure 9AIs a schematic diagram of a wireless communication device 90, which includes a filter 93 in a radio frequency front end 92 according to one embodiment. The filter 93 may include a BAW resonator of BAW components according to any suitable principles and advantages discussed herein. The wireless communication device 90 can be any suitable wireless communication device. For example, the wireless communication device 90 can be a mobile phone such as a smart phone. As shown, the wireless communication device 90 includes an antenna 91, an RF front end 92, a transceiver 94, a processor 95, a memory 96, and a user interface 97. The antenna 91 can transmit RF signals provided by the RF front end 92. Such RF signals may include carrier aggregation signals.

[0081] The RF front end 92 may include one or more power amplifiers, one or more low noise amplifiers, one or more RF switches, one or more receive filters, one or more transmit filters, one or more duplex filters, one or more multiplexers, one or more frequency multiplexing circuits, etc. or any suitable combination thereof. The RF front end 92 can transmit and receive RF signals associated with any suitable communication standard. The filter 93 may include a BAW resonator of BAW components, which includes any suitable combination of features discussed with reference to any of the embodiments discussed above.

[0082] The transceiver 94 can provide RF signals to the RF front end 92 for amplification and / or other processing. The transceiver 94 can also process RF signals provided by the low noise amplifier of the RF front end 92. The transceiver 94 communicates with the processor 95. The processor 95 can be a baseband processor. The processor 95 can provide any suitable baseband processing functions for the wireless communication device 90. The memory 96 can be accessed by the processor 95. The memory 96 can store any suitable data for the wireless communication device 90. The user interface 97 can be any suitable user interface, such as a display with touch screen functionality.

[0083] Figure 9B Is a schematic diagram of a wireless communication device 100, which includes a filter 93 in a radio frequency front end 92 and a second filter 103 in a diversity receiving module 102. Except that the wireless communication device 100 further includes diversity receiving features, the wireless communication device 100 is the same as the Figure 9A wireless communication device 90. As Figure 9B illustrated, the wireless communication device 100 includes a diversity antenna 101, a diversity module 102 configured to process signals received by the diversity antenna 101 and including a filter 103, and a transceiver 104 that communicates with both the radio frequency front end 92 and the diversity receiving module 102. The filter 103 may include a BAW resonator of BAW components, which includes any suitable combination of features discussed with reference to any of the embodiments discussed above.

[0084] Any of the above embodiments may be implemented in association with a mobile device such as a cellular phone. The principles and advantages of the embodiments may be used in any system or device that may benefit from any of the embodiments described herein, such as any uplink cellular device. The teachings herein may be applied to a variety of systems. Although the present disclosure includes some example embodiments, the teachings described herein may be applied to a variety of architectures. Any of the principles and advantages discussed herein may be implemented in association with an RF circuit configured to process signals having frequencies in the range of about 30 kilohertz (kHz) to 300 gigahertz (GHz), such as frequencies in the range of about 450 MHz to 8.5 GHz.

[0085] Aspects of the present disclosure may be implemented in a variety of electronic devices. Examples of electronic devices may include, but are not limited to, consumer electronics products, components of consumer electronics products such as wafer and / or acoustic filter components and / or packaged RF modules, uplink wireless communication devices, wireless communication infrastructure, electronic test equipment, etc. Examples of electronic devices may include, but are not limited to, mobile phones such as smart phones, wearable computing devices such as smart watches or earphones, telephones, televisions, computer monitors, computers, modems, handheld computers, laptop computers, tablet computers, personal digital assistants (PDAs), microwave ovens, refrigerators, automobiles, stereo systems, DVD players, CD players, digital music players such as MP3 players, radios, portable video cameras, cameras, digital cameras, portable storage chips, washing machines, dryers, washer / dryers, copiers, fax machines, scanners, multifunction peripherals, wrist watches, clocks, etc. In addition, the electronic devices may include unfinished products.

[0086] Unless the context clearly requires otherwise, throughout the specification and claims, the words "comprise," "comprising," "include," "including," etc. shall be construed in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including, but not limited to." As used herein generally, the word "coupled" means that two or more elements that may be directly connected or connected by means of one or more intermediate elements. Similarly, as used herein generally, the word "connected" means that two or more elements that may be directly connected or connected by means of one or more intermediate elements. Additionally, when used in this application, the words "herein," "above," "below," and words of similar import shall refer to this application as a whole and not to any particular part of this application. Where context permits, the words in the above detailed description that use the singular or plural may also include the plural or singular respectively. The word "or" means a list of two or more items, and the word encompasses all of the following interpretations of the list: any item in the list, all items in the list, and any combination of items in the list.

[0087] In addition, conditional language used herein, such as "may", "can", "could", "might", "example", "for example", "such as", etc., unless specifically stated otherwise or otherwise understood in the context in which it is used, generally is intended to convey that certain embodiments include while other embodiments do not include certain features, elements, and / or states. Thus, such conditional language generally is not intended to imply that one or more embodiments necessarily require features, elements, and / or states in any way.

[0088] Although certain embodiments have been described, these embodiments have been presented by way of example only and are not intended to limit the scope of the disclosure. In fact, the novel devices, methods, and systems described herein may be implemented in many other forms; furthermore, various omissions, substitutions, and changes in the form of the methods and systems described herein may be made without departing from the spirit of the disclosure. For example, although the blocks are presented in a given arrangement, alternative embodiments may use different components and / or circuit topologies to perform similar functions, and some blocks may be deleted, moved, added, subdivided, combined, and / or modified. Each of these blocks may be implemented in a variety of different ways. Any suitable combination of the elements and acts of the various embodiments described above may be combined to provide other embodiments. The appended claims and their equivalents are intended to cover such forms or modifications that will fall within the scope and spirit of the disclosure.

Claims

1. A method of manufacturing a monolithic bulk acoustic wave component, the method comprising: A buffer layer is formed above the substrate of the array of bulk acoustic wave components so as to form exposed blocks between the respective bulk acoustic wave components, and the substrate is a silicon substrate; and The bulk acoustic wave components are plasma cut along the exposed blocks so as to singulate the bulk acoustic wave components, and the buffer layer has an etching rate that is at least 30 times slower than the silicon etching rate during the plasma cutting.

2. The method according to claim 1, wherein, Each of the singulated bulk acoustic wave components includes a bulk acoustic wave resonator and a cover encapsulating the bulk acoustic wave resonator, and the cover includes a sidewall that is 5 micrometers or less from the edge of the substrate of the respective singulated bulk acoustic wave component.

3. The method according to claim 2, wherein, The sidewall is at least 1 micrometer from the edge of the respective singulated bulk acoustic wave component.

4. The method according to claim 2, wherein, The sidewall includes copper.

5. The method according to claim 1, wherein, The plasma cutting includes etching through both the substrate and the cover substrate, and each of the singulated bulk acoustic wave components includes a bulk acoustic wave resonator located above the substrate and below the cover substrate.

6. The method according to claim 5, wherein, The cover substrate is a silicon substrate.

7. The method according to claim 1, further comprising forming a conductor above the substrate, the conductor extending laterally from a through hole extending through the substrate, and the conductor being electrically connected to a conductive layer in the through hole.

8. The method according to claim 7, wherein, The formation of the buffer layer is performed such that the buffer layer is above at least a portion of the conductor.

9. The method according to claim 7, further comprising forming solder above the conductor such that the solder does not overlap with the through hole.

10. The method according to claim 1, forming the buffer layer includes forming the exposed block by means of a lithography process.

11. The method according to claim 1, wherein, Each of the bulk acoustic wave components includes a thin film bulk acoustic wave resonator.

12. A method of manufacturing a bulk acoustic wave component, the method comprising: A first wafer having bulk acoustic wave resonators thereon is provided and bonded to a second wafer, and the second wafer is above and spaced apart from the bulk acoustic wave resonators, and the first wafer is a silicon wafer; A buffer layer is formed on the side of the first wafer opposite to the bulk acoustic wave resonators such that blocks are exposed; and Along the exposed blocks, the first wafer and the second wafer are plasma cut through to form singulated bulk acoustic wave components, and the buffer layer has an etching rate that is at least 30 times slower than the silicon etching rate during the plasma cutting.

13. The method according to claim 12, wherein, The second wafer is a silicon wafer.

14. The method according to claim 12, wherein, Each of the singulated bulk acoustic wave components includes a bulk acoustic wave resonator among the bulk acoustic wave resonators and a cover encapsulating the bulk acoustic wave resonator, and the cover includes a sidewall.

15. The method according to claim 14, wherein, The sidewall is in the range of 1 micrometer to 5 micrometers from the edge of the substrate of the respective singulated bulk acoustic wave component, and the substrate corresponds to a portion of the first wafer before plasma cutting.

16. A method of manufacturing a bulk acoustic wave component, the method comprising: A buffer layer is formed above the silicon substrate of the bulk acoustic wave component such that blocks are exposed; and The bulk acoustic wave components are plasma cut along the exposed blocks so as to singulate the bulk acoustic wave components, and each of the singulated bulk acoustic wave components includes a bulk acoustic wave resonator and a cover encapsulating the bulk acoustic wave resonator, and the cover includes a silicon cover substrate and a sidewall that is spaced apart from the edge of the silicon substrate of the respective singulated bulk acoustic wave component by a distance in the range of 1 micrometer to 5 micrometers.

17. The method according to claim 16, wherein,The sidewall includes copper, and the buffer layer includes resin.

18. The method according to claim 16, wherein, The bulk acoustic wave resonator is a thin film bulk acoustic wave resonator.

19. A bulk acoustic wave component, comprising: A substrate, and the substrate is a silicon substrate; At least one bulk acoustic wave resonator on the substrate; A buffer layer located on the side of the substrate opposite to the bulk acoustic wave resonators, and the buffer layer includes a material having an etching rate that is at least 30 times slower than the silicon etching rate; and A cover encapsulating the at least one bulk acoustic wave resonator, the cover including sidewalls spaced apart from an edge of the substrate, the sidewalls being 5 micrometers or less away from the edge of the substrate.

20. The bulk acoustic wave component according to claim 19, wherein, The sidewalls are 3 micrometers or less away from the edge of the substrate.

21. The bulk acoustic wave component according to claim 19, wherein, The sidewalls are at least 1 micrometer away from the edge of the substrate.

22. The bulk acoustic wave component according to claim 19, further comprising a through hole extending through the substrate and a conductive layer in the through hole, and a part of the buffer layer is in the through hole.

23. The bulk acoustic wave component according to claim 19, further comprising a through hole extending through the substrate, a conductor extending laterally from the through hole and electrically connected to the conductive layer in the through hole, and a solder on the conductor and positioned laterally from the through hole.

24. The bulk acoustic wave component according to claim 19, wherein, The at least one bulk acoustic wave resonator includes a thin film bulk acoustic wave resonator.

25. The bulk acoustic wave component according to claim 19, wherein, The at least one bulk acoustic wave resonator includes a firmly mounted resonator.

26. The bulk acoustic wave component according to claim 19, wherein, The top of the cover includes a silicon cover substrate.

27. The bulk acoustic wave component according to claim 19, wherein, The sidewalls include copper.

28. The bulk acoustic wave component according to claim 19, wherein, The at least one bulk acoustic wave resonator includes a plurality of bulk acoustic wave resonators included in a filter arranged to filter a radio frequency signal.

29. The bulk acoustic wave component according to claim 28, wherein, The plurality of bulk acoustic wave resonators includes at least 10 bulk acoustic wave resonators.

30. A bulk acoustic wave component, comprising: A silicon substrate; At least one bulk acoustic wave resonator on the silicon substrate; A buffer layer on a side of the silicon substrate opposite to the bulk acoustic wave resonator, the buffer layer including a material having an etching rate at least 30 times slower than the silicon etching rate; And A cover encapsulating the at least one bulk acoustic wave resonator, the cover including a cover substrate and sidewalls, the cover substrate including silicon, the sidewalls being spaced apart from an edge of the silicon substrate by a distance in a range from 1 micrometer to 5 micrometers.

31. The bulk acoustic wave component according to claim 30, further comprising a through hole extending through the silicon substrate and a conductive layer in the through hole, and a part of the buffer layer is in the through hole.

32. The bulk acoustic wave component according to claim 30 further includes a through hole extending through the silicon substrate, a conductor extending laterally from the through hole and electrically connected to the conductive layer in the through hole, and a solder on the conductor and positioned laterally with respect to the through hole.

33. The bulk acoustic wave component according to claim 30, wherein, The sidewalls include copper.

34. The bulk acoustic wave component according to claim 30, wherein, The at least one bulk acoustic wave resonator includes at least 10 bulk acoustic wave resonators included in an acoustic wave filter arranged to filter a radio frequency signal.

35. A wireless communication device, comprising: An antenna; And A bulk acoustic wave component including a silicon substrate, a bulk acoustic wave resonator on the silicon substrate, a buffer layer on a side of the silicon substrate opposite to the bulk acoustic wave resonator, and a cover encapsulating the bulk acoustic wave resonator, the buffer layer including a material having an etching rate at least 30 times slower than the silicon etching rate, the cover including sidewalls spaced 5 micrometers or less from an edge of the silicon substrate, and the bulk acoustic wave resonator being included in a filter in communication with the antenna.

36. The wireless communication device according to claim 35, wherein, The wireless communication device is configured as a mobile phone.

37. The wireless communication device according to claim 35 further includes a radio frequency amplifier communicating with the filter and a switch coupled between the filter and the antenna.

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