Acoustic volume wave components and methods for plasma cutting the same

Abstract

A method (10) for producing isolated acoustic volume wave components (36; 40; 42), comprising: Forming (16) a buffer layer (32) over a silicon substrate (22) an arrangement of acoustic volume wave components (36; 40; 42) to form exposed roads (34) between individual acoustic volume wave components (36; 40; 42); and Plasma cutting (18) of the acoustic volume wave components (36; 40; 42) along the exposed roads (34) in order to isolate the acoustic volume wave components (36; 40; 42), wherein the buffer layer (32) has an etch rate which is over 30 times slower during plasma cutting compared to an etch rate of silicon.

Description

BACKGROUND Technical area

[0001] Embodiments of this disclosure relate to acoustic wave components and in particular to bulk acoustic wave components (“bulk acoustic wave components”, BAW). Description of related technology

[0002] Acoustic wave filters can be used in electronic high-frequency systems. For example, filters in the high-frequency front end of a mobile phone may include acoustic wave filters. An acoustic wave filter can filter a high-frequency signal. An acoustic wave filter can be a bandpass filter. Multiple acoustic wave filters can be arranged as a multiplexer. For example, two acoustic wave filters can be arranged as a duplexer.

[0003] An acoustic wave filter can incorporate a variety of acoustic wave resonators arranged to filter a high-frequency signal. Examples of acoustic wave filters include surface acoustic wave (SAW) filters and bulk acoustic wave (BAW) filters. BAW filters include BAW resonators. Examples of BAW resonators include film bulk acoustic wave resonators (FBARs) and solidly mounted resonators (SMRs). In BAW resonators, acoustic waves propagate within the volume of a piezoelectric layer.

[0004] BAW components can be housed BAW resonators enclosed within a sealed area. Housing structures increase the size of BAW components. Therefore, there is a need for ways to reduce the size of BAW components without compromising reliability and performance.

[0005] Document US 2018 / 0159493A1 discloses a method for manufacturing individual BAW resonator modules, each comprising several BAW resonators and a housing cap with side walls over these BAW resonators. SUMMARY OF CERTAIN INVENTIVE ASPECTS

[0006] One aspect of this disclosure relates to a method for producing isolated acoustic volume wave components. The method includes forming a buffer layer over a substrate containing an array of acoustic volume wave components to create exposed pathways between individual acoustic volume wave components. The method also includes plasma cutting the acoustic volume wave components along the exposed pathways to isolate the acoustic volume wave components.

[0007] Each of the isolated acoustic volume wave components can have an acoustic volume wave resonator and a cap enclosing the acoustic volume wave resonator. The cap can have a sidewall that is 5 microns or less from an edge of the substrate of the respective isolated acoustic volume wave component. The sidewall can be at least 1 micron from the edge of the substrate of the respective isolated acoustic volume wave component. The sidewall can include copper.

[0008] Plasma cutting can involve etching through both the substrate and a cap substrate. The acoustic volume wave component can include an acoustic volume wave resonator located above the substrate and below the cap substrate. The substrate and the cap substrate can be silicon substrates.

[0009] The method can further include the formation of a conductor over the substrate. The conductor can extend laterally from a through-hole or via that extends through the substrate. The conductor can be electrically connected to a conductive layer in the through-hole. The buffer layer can be formed such that it covers at least part of the conductor. The method can further include the formation of solder material over the conductor, such that the solder material does not overlap the through-hole.

[0010] The substrate is a silicon substrate. The buffer layer is a material that etches at least 30 times slower than silicon during plasma cutting. The buffer layer may include a resin. Forming the buffer layer may involve creating the exposed roads using a photolithographic process.

[0011] The acoustic volume wave components can each have an acoustic thin-film volume wave resonator.

[0012] Another aspect of this disclosure relates to a method for producing acoustic volume wave components. The method comprises providing a first wafer which is connected or bonded to a second wafer. Acoustic volume wave resonators are present on the first wafer. The second wafer lies above and spaced apart from the acoustic volume wave resonators. The method includes forming a buffer layer on one side of the first wafer, opposite the acoustic volume wave resonators, so that roads are exposed. The method includes plasma cutting through the first wafer and the second wafer along the exposed roads to form isolated acoustic volume wave components.

[0013] The first wafer and the second wafer can be silicon wafers.

[0014] Each of the isolated acoustic volume wave components can have an acoustic volume wave resonator and a cap enclosing the acoustic volume wave resonator. The cap can have a side wall. The side wall can be located between 1 micron and 5 microns away from an edge of a substrate corresponding to a region of the first wafer before plasma cutting for the respective isolated acoustic volume wave component.

[0015] Another aspect of this disclosure relates to a method for fabricating acoustic volume wave components. The method comprises forming a buffer layer over a silicon substrate of acoustic volume wave components, thereby exposing roads. The method also includes plasma cutting the acoustic volume wave components along the exposed roads to isolate the acoustic volume wave components. The isolated acoustic volume wave components each comprise an acoustic volume wave resonator and a cap enclosing the acoustic volume wave resonator. The cap may have a silicon cap substrate and a side wall located between 1 micron and 5 microns from an edge of the silicon substrate of the respective isolated acoustic volume wave component.

[0016] The side wall can include copper. The buffer layer can include a resin. The acoustic volume wave resonator can be a thin-film acoustic volume wave resonator.

[0017] Another aspect of this disclosure relates to an acoustic volume wave component comprising a substrate, at least one acoustic volume wave resonator on the substrate, and a cap enclosing the at least one acoustic volume wave resonator. The cap includes a side wall spaced from an edge of the substrate. The side wall is spaced 5 microns or less from the edge of the substrate.

[0018] The side wall can be 3 microns or less away from the edge of the substrate. The side wall can be at least 1 micron away from the edge of the substrate.

[0019] The acoustic volume wave component can further include a through hole or via which extends through the substrate, a conductive layer in the through hole, and a buffer layer in the through hole.

[0020] The acoustic volume wave component can further include a through hole or via which extends through the substrate, a conductor which extends laterally away from the through hole and is electrically connected to a conductive layer in the through hole, and solder material on the conductor which is arranged laterally next to the through hole.

[0021] The at least one acoustic volume wave resonator can be a thin-film acoustic volume wave resonator. The at least one acoustic volume wave resonator can be a fixed resonator.

[0022] The substrate can be a silicon substrate. An upper region of the cap can be a silicon cap substrate.

[0023] The side wall may include copper.

[0024] The at least one acoustic volume wave resonator can comprise a plurality of acoustic volume wave resonators arranged in a filter for filtering a high-frequency signal. The plurality of acoustic volume wave resonators can include at least 10 acoustic volume wave resonators.

[0025] Another aspect of this disclosure relates to an acoustic volume wave component comprising a silicon substrate, at least one acoustic volume wave resonator on the silicon substrate, and a cap enclosing the at least one acoustic volume wave resonator. The cap includes a cap substrate and a side wall. The cap substrate comprises silicon. The side wall is spaced from an edge of the silicon substrate by a distance in the range of 1 micron to 5 microns.

[0026] The acoustic volume wave component can further comprise a through hole or via which extends through the silicon substrate, a conductive layer in the through hole, and a buffer layer in the through hole.

[0027] The acoustic volume wave component can further include a through hole or via which extends through the substrate, a conductor which extends laterally away from the through hole and is electrically connected to a conductive layer in the through hole, and solder material on the conductor which is arranged laterally next to the through hole.

[0028] The side wall can include copper. The at least one acoustic volume wave resonator can comprise at least 10 acoustic volume wave resonators arranged in an acoustic wave filter for filtering a high-frequency signal.

[0029] Another aspect of this disclosure concerns a wireless communication device comprising an antenna and an acoustic volume wave component. The acoustic volume wave component includes a substrate, acoustic volume wave resonators on the substrate, and a cap enclosing the acoustic volume wave resonators. The cap includes a side wall spaced 5 microns or less from an edge of the substrate. The acoustic volume wave resonators are arranged in a filter in communicative interaction with the antenna.

[0030] The wireless communication device can be a mobile phone.

[0031] The wireless communication device may further include a high-frequency amplifier that is in communicative interaction with the filter, and a switch that is coupled between the filter and the antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The embodiments of this disclosure will now be described in non-limiting examples with reference to the accompanying drawings. Fig. Figure 1 shows a flowchart of an exemplary process for the production of acoustic volume wave components according to one embodiment. Fig. Figures 2A to 2E are cross-sectional diagrams illustrating an exemplary method for the production of acoustic volume wave components according to one embodiment. Fig. Figure 3A shows a cross-sectional diagram of an acoustic volume wave component according to one embodiment. Fig. Figure 3B shows a cross-sectional diagram of an acoustic volume wave component according to another embodiment. Fig. Figure 4 shows a schematic representation of a transmitting filter which has acoustic volume wave resonators of an acoustic volume wave component according to one embodiment. Fig. Figure 5 shows a schematic representation of a receiving filter which has acoustic volume wave resonators of an acoustic volume wave component according to one embodiment. Fig. Figure 6 shows a schematic representation of a high-frequency system which has an acoustic volume wave component according to one embodiment. Fig. Figure 7 shows a schematic representation of a high-frequency module which has an acoustic volume wave component according to one embodiment. Fig. Figure 8 shows a schematic representation of a high-frequency module which has an acoustic volume wave component according to one embodiment. Fig. Figure 9A shows a schematic block diagram of a wireless communication device incorporating a filter according to one or more embodiments. Fig. Figure 9B shows a schematic block diagram of another wireless communication device incorporating a filter according to one or more embodiments. DETAILED DESCRIPTION OF CERTAIN VERSIONS

[0033] The following description of certain embodiments presents various descriptions of specific embodiments. However, the innovations described here can be implemented in a variety of ways, for example, through the definition and scope of the claims. Reference is made in this description to the drawings, in which similar reference numerals may denote identical or functionally similar elements. It should be noted that the elements shown in the figures are not necessarily drawn to scale. Furthermore, it should be noted that certain embodiments may include more elements than shown in a drawing and / or a subset of the elements shown in a drawing. In addition, some embodiments may include any suitable combination of features from two or more drawings.

[0034] Acoustic wave filters can filter high-frequency (RF) signals in a variety of applications, such as in the RF front end of a mobile phone. An acoustic wave filter can incorporate bulk acoustic wave (BAW) components. The BAW component can comprise a single chip. The BAW component can have one or more BAW resonators on a substrate, such as a silicon substrate. The one or more BAW resonators can be enclosed by a cap of the BAW component. The cap can have another silicon substrate as well as sidewalls. The cap can form a hermetic seal around the one or more BAW resonators. The sidewalls can be made of materials such as copper.

[0035] BAW components can be fabricated by sawing connected wafers with a cavity between them. Some BAW components exhibited chipping on the side facing the cavity. In the case of relatively large chips, a hermetic seal around BAW resonators can be breached. To reduce and / or eliminate the risk of chipping, a gap can be left between an edge of a BAW component and the sealed area. This gap can be, for example, between 15 and 20 microns or micrometers from a sidewall of a cap to a sawn edge of a BAW component. This gap may consume build area of ​​the BAW component.

[0036] Aspects of this disclosure relate to a plasma cutting process for acoustic volume wave components. A buffer layer can be formed over acoustic volume wave components to cover a rewiring layer. The buffer layer can be formed in such a way as to expose pathways for cutting. The buffer layer can serve as a masking layer for plasma cutting. BAS components can be singulated by plasma cutting. Plasma cutting can result in less chipping of BAW components compared to other cutting or sawing techniques such as blade cutting or laser cutting. In plasma cutting, a sidewall of a cap enclosing one or more BAW resonators can be positioned closer to a cut edge of the BAW component than with other cutting or sawing techniques, without increasing the risk of chipping of BAW components.Plasma cutting can involve cutting through an upper and a lower wafer across a cavity. The upper and lower wafers can be silicon wafers.

[0037] Plasma cutting allows for a reduction in the size of BAW components. By decreasing the distance between a cap's sidewall and an edge of the BAW component, more BAW components can be placed on a single wafer. Furthermore, the BAW components can occupy less build space on modules.

[0038] Blade cutting techniques typically produce sharp cut edges and can lead to lateral stresses when cutting a chip. This can result in fractures and / or chipping at the sharp cut edge of a blade-cut component. Plasma cutting allows a cutting pattern to be generated via a photolithographic process, largely avoiding mechanical stresses during the plasma cutting process. Accordingly, plasma cutting can maintain a sharp cut edge while reducing and / or preventing damage that would result from mechanical failure. In certain cases, plasma cutting of BAW components can produce corners that are more rounded, resulting in more reliable performance compared to mechanical fracture techniques. Rounded corners can reduce and / or eliminate the risk of BAW components breaking and / or chipping.

[0039] Using the manufacturing processes disclosed herein, the yield of BAW components from a single wafer can be increased by approximately 10% to 18% in certain cases compared to conventional manufacturing processes. This yield improvement can reduce manufacturing costs. Manufacturing costs can be reduced due to the improved yield even if higher costs are incurred through additional process steps and / or equipment acquisition.

[0040] Methods for manufacturing BAW components by means of plasma cutting are disclosed. Fig. Figure 1 shows a flowchart of an exemplary process 10 for the production of acoustic volume wave components according to one embodiment. The process 10 is described with reference to the [reference to be added]. Fig. Sections 2A to 2E illustrate cross-sectional layers. Each of the methods described herein may have more or fewer steps, and these steps can be carried out in any order, depending on suitability.

[0041] In process 10, block 12 involves providing a substrate with one or more BAW resonators enclosed within a cap. The substrate can be a silicon substrate. The cap can have sidewalls and a second substrate, which together enclose the one or more BAW resonators. The one or more BAW resonators can be a film bulk acoustic wave resonator (FBAR) and / or a solidly mounted resonator (SMR).

[0042] A rewiring layer is formed above the substrate at block 14. The rewiring layer comprises a conductor that extends laterally, or along the substrate surface, from a through-hole through the substrate. The rewiring layer can be referred to as a wiring layer. The rewiring layer can be formed by the same processing steps used to form a conductive layer in one or more of the through-holes through the substrate of a BAW component. The rewiring layer and the conductive layer can be, for example, approximately 5 microns and micrometers thick, respectively. Solder material can be formed over a portion of the rewiring layer. The rewiring layer can create an electrical connection between the conductive layer in one of the through-holes through the substrate and the solder material of the BAW component.Using the rewiring layer, solder material can be formed over any suitable part of a substrate. For example, the solder material can be formed laterally spaced from a through-hole in the substrate. In certain configurations, the solder material and the through-hole in the substrate do not overlap.

[0043] Fig. Figure 2A illustrates a cross-sectional view of a multitude of BAW components together with the rewiring layer formed at block 14 of process 10. As shown in Fig. As shown in Figure 2A, the multitude of BAW components has not yet been separated. Fig. Figure 2A illustrates a cap substrate 21, a substrate 22, side walls 23, BAW resonators 24, air cavities 25, through holes or vias 26 through the substrate, a conductive layer 27 in corresponding through holes or vias 26 through the substrate, a rewiring layer 28, and electrodes 29. Before individual BAW components are separated, a first wafer comprises the substrate 22 of each individual BAW component, and a second wafer comprises the cap substrate 21 of each individual BAW component. As shown, the first wafer is connected to, or bonded to, the second wafer.

[0044] The BAW resonators 24 are enclosed within a cap that includes the cap substrate 21 and sidewalls 23. The BAW resonators 24 are enclosed within the cap before the rewiring layer 28 is formed. As shown, a bonding layer 30 and a cap layer 31 can be arranged between the substrate 22 and the sidewall 23. The bonding layer 30 can be a gold layer. The cap layer 31 can be a tin cap layer. The cap forms a hermetic seal around the BAW resonators 24. Accordingly, an air cavity 25 can be enclosed within the cap around the BAW resonators 24. In some cases, a BAW component can have 10 to 50 BAW resonators 24 enclosed within a cap. The BAW resonators 24 can have one or more FBARs. Alternatively or additionally, the BAW resonators 24 can have one or more SMRs.The BAW resonators 24 can be incorporated into one or more filters. The substrate 21 can be a silicon substrate. The side walls can be made of copper.

[0045] The BAW resonators 24 are located on the substrate 22 and enclosed by the cap. The substrate 22 can be a silicon substrate. The conductive layer 27 in the through-holes or vias 26 through the substrate can create an electrical connection between one or more of the BAW resonators 24 and elements on the opposite side of the substrate 22. As shown, the rewiring layer 28, which is formed at block 14, lies above the substrate 22 and extends laterally from the through-holes or vias 26 through the substrate. Accordingly, electrodes 29 can be formed above the rewiring layer 28 and laterally from the through-holes or vias 26 through the substrate. The rewiring layer 28 lies on the opposite side of the substrate 22 from the BAW resonators 24. The electrodes 29 provide terminals for external connections to BAW components.The rewiring layer 28 allows the electrodes 29 to be positioned at any suitable location within a BAW component. The rewiring layer 28 can provide shielding. Specifically, it can shield the BAW resonators 24 from external components and vice versa.

[0046] Referring again to Fig. In Block 16, a buffer layer is formed over the substrate, exposing roads. The buffer layer can be formed using a photolithographic process. Forming the buffer layer can involve depositing a layer of buffer material, which masks certain areas above the buffer material, and illuminating it with light to remove the buffer material above the roads. A surface of the substrate can be exposed along the roads. The buffer layer can provide encapsulation for BAW components on a side opposite the cap substrate. The buffer layer can be formed over the rewiring layer in Block 14.

[0047] Fig. Figure 2B illustrates a cross-sectional view of BAW components, which includes a buffer layer 32 formed at block 16 of the process 10. The buffer layer 32 lies above the substrate 22. The buffer layer 32 is located on a side of the substrate 22 opposite the BAW resonators 24. Part of the buffer layer 32 lies within through holes or vias 26 through the substrate. The buffer layer 32 also lies above parts of the rewiring layer 28. As shown in Fig. As shown in Figure 2B, the buffer layer 32 is designed such that the electrodes 29 remain exposed. The buffer layer 32 comprises a material that acts as an etch mask, resisting etching while the substrate 22 is plasma-cut. For example, the buffer layer 32 can be made of a material that etches less readily than silicon, whereas silicon is etched on a silicon substrate 22. Typically, the etch rate of the buffer layer 32 is over 30 times slower compared to the etch rate of silicon. Therefore, a typical buffer layer thickness is sufficient for plasma cutting wafers. The buffer layer 32 can be a polyimide layer, a phenolic resin layer such as a rubber-filled phenolic resin layer, or any other suitable buffer layer. The roads 34 facilitate the cutting of the BAW components.

[0048] Fig. Figure 2C illustrates an enlarged partial representation of 35 of the in Fig. 2B shows the BAW components. As shown, the roads 34 can have a thickness D S exhibit the thickness D S is suitable for plasma cutting as shown. The thickness D S The thickness of road 34 can range from approximately 10 microns to approximately 20 microns, particularly between 10 microns and 15 microns. For example, the thickness D S The dimensions of streets 34 are approximately 15 microns. Fig. Figure 2C also illustrates that a bonding layer 30 and a capping layer 31 may be located between the substrate 22 and the side wall 23.

[0049] Referring again to Fig. 1. At Block 18, the BAW components along the exposed roads are plasma-cut. This separates the BAW components. In other words, the BAW components are separated from each other into individual BAW components by plasma cutting. The plasma cutting may involve dry etching through a substrate on which the BAW resonators are located and through a cap substrate. Between the substrate and the cap substrate under the road (e.g., as in Fig. (as shown in Figure 2B) a cavity may be present during etching. In one example, the substrate and the cap substrate may both be silicon substrates etched at a rate of approximately 20 microns per minute. In this example, the substrate and cap substrate combined may be approximately 200 microns thick, and it may take approximately 10 minutes to etch through approximately 200 microns of silicon. Using plasma cutting, chipping of isolated BAW components can be reduced compared to other cutting techniques such as blade cutting or laser cutting. For plasma cutting, a photolithographic process can replicate any suitable road pattern. In certain cases, this can result in rounded corners for isolated BAW components. Such rounded corners can reduce the risk of the BAW component breaking and / or chipping, thus improving the reliability of the BAW component.

[0050] Fig. Figure 2D illustrates a cross-sectional view of the BAW components after plasma cutting at block 18 of process 10. Plasma cutting along roads can remove portions of the substrate 22 and the cap substrate 21, thereby isolating individual BAW components. A multitude of isolated BAW components 36 are in Fig. Shown in 2D. Adhesive tape 37 can hold the individual BAW components 36 together. The adhesive tape 37 can be laminated onto the BAW components before plasma cutting.

[0051] Fig. Figure 2E illustrates an enlarged partial representation 38 of the in Fig. 2D representation of isolated BAW components 36. As shown, a distance D can be EThe distance from a side wall 23 to an edge of the substrate 22 of a single BAW component 36 can be relatively small. Using a buffer layer as a mask for plasma cutting, a photolithographic process can be employed. Therefore, plasma cutting provides higher accuracy compared to other cutting techniques such as blade cutting or laser cutting with a mechanical system accuracy. Plasma cutting, for example, can be performed with an accuracy of + / - 2 microns. In contrast, the mechanical accuracy in the case of blade cutting is + / - 10 microns, and chipping of 5 to 10 microns can occur. With the improved accuracy and the reduced risk of chipping, the distance D can be E from a side wall 23 to an edge of the substrate 22 of a single BAW component 36 during plasma cutting. The distance D EThe distance from a side wall 23 to an edge of the substrate 22 of the isolated BAW component 36 can be less than 5 microns. The distance D E can be less than 3 microns. In an example, the distance D E approximately 2.5 microns. The distance D E is, as shown, greater than zero. In some cases, the distance D can E in a range between 1 micron and 5 microns, particularly in a range between 1 micron and 3 microns. The side wall 23 and the edge of the substrate 22 can, in certain cases, be essentially flush with each other in a single BAW component.

[0052] Accordingly, the distance between corresponding sidewalls of 23 adjacent BAW components on a wafer can be smaller during plasma cutting. A distance D SW The sum of the road thickness D between side walls of 23 corresponding adjacent isolated BAW components corresponds to the total road thickness D.S and twice the distance D E in Fig. 2E. The distance D SW For example, it can lie in a range between approximately 10 microns and approximately 30 microns. In some cases, the distance D can SW in a range between approximately 10 microns and approximately 20 microns. For example, the road thickness D S approximately 15 microns and the distance D E can be approximately 2.5 microns, which corresponds to a distance D SW of about 20 microns in the Fig. 2E would result in the cross-sectional representation shown.

[0053] Fig. Figure 3A shows a cross-sectional diagram of an acoustic volume wave component 40 according to one embodiment. The BAW component 40 can be produced by a process involving plasma cutting. For example, the acoustic volume wave component 40 can correspond to a single BAW component produced by method 10 of the Fig. 1 has been manufactured.

[0054] As in Fig. As shown in 3A, the distance D can be E The distance D from a side wall 23 to an edge of the substrate 22 of a single BAW component 40 resulting from plasma cutting may be relatively small. E may be located in any of the areas disclosed herein and / or exhibit any of the values ​​disclosed herein, such as in connection with Fig. 2E described. In the illustrated BAW component 40, BAW resonators 24 are enclosed within a cap that includes a cap substrate 21 and side walls 23. The BAW resonators 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 enclosed within the cap of the BAW component 40. For example, 10 to 50 BAW resonators 24 can be enclosed within the cap of the BAW component 40. The BAW resonators 24 can be electrically connected to an electrode 29 via a conductive layer 27 in a through-hole or via 26 through the substrate and a rewiring layer 28. The buffer layer 32 extends over the rewiring layer 28 and is contained within the through-hole 26 through the substrate in the BAW component 40.

[0055] Fig. Figure 3B shows a cross-sectional diagram of an acoustic volume wave component 42 according to one embodiment. The BAW component 42 can be produced by a process involving plasma cutting. For example, the acoustic volume wave component 42 can correspond to a single BAW component produced by method 10 of the Fig. 1 has been manufactured. BAW component 42 corresponds to BAW component 40 of the Fig. 3A, except that the BAW component 42 has a through-hole or via 26 which is filled with a conductive protective layer 43 instead of a conductive layer 27. The conductive protective layer 43 can, for example, be a copper layer. The acoustic volume wave component 42 illustrates that the through-hole 26 can be filled with a conductive protective layer 43.

[0056] One or more acoustic volume wave resonators of an acoustic volume wave component with any suitable combination of features disclosed herein can be arranged in a filter designed to filter a radio frequency signal in an operating band of fifth-generation (5G) New Radio (NR) within Frequency Range 1 (FR1). A filter designed to filter a radio frequency signal in a 5G NR operating band can include one or more acoustic volume wave resonators of any acoustic volume wave component as disclosed herein. FR1 can, for example, be located between 410 megahertz (MHz) and 7.125 gigahertz (GHz), as specified in a current 5G NR specification.One or more acoustic volume wave resonators of an acoustic volume wave component in accordance with any suitable of the principles and advantages disclosed herein may be arranged in a filter designed to filter a high-frequency signal in an operating band of fourth-generation Long Term Evolution (LTE) (“fourth generation”, 4G), and / or in a filter having a passband spanning at least one 4G-LTE operating band and at least one 5G-NR operating band.

[0057] Fig. Figure 4 shows a schematic representation of a transmit filter 45, which comprises acoustic volume wave resonators of an acoustic volume wave component according to one embodiment. The transmit filter 45 can be a bandpass filter. The transmitted filter 45 shown is designed to filter a high-frequency signal received at a transmit terminal TX and to provide a filtered output signal at an antenna terminal ANT. The transmit filter 45 comprises 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 to TS7 and / or TP1 to TP5 can be incorporated into a BAW component designed in accordance with any suitable principles and advantages disclosed herein. For example, the BAW component 40 of the Fig. 3A or the BAW component 42 of the Fig. 3B all of the BAW resonators of the transmitting filter 45 may be incorporated. In certain cases, a BAW component designed in accordance with any suitable principles and advantages disclosed herein may incorporate BAW resonators of two or more acoustic wave filters. Any suitable number of series BAW resonators and shunt BAW resonators may be included in a transmitting filter 45.

[0058] Fig. Figure 5 shows a schematic representation of a receiving filter 50, which comprises acoustic volume wave resonators of an acoustic volume wave component according to one embodiment. The receiving filter 50 can be a bandpass filter. The receiving filter 50 shown is designed to filter a high-frequency signal received at an antenna port ANT and to provide a filtered output signal at a receiver port RX. The receiving filter 50 comprises series BAW resonators RS1, RS2, RS3, RS4, RS5, RS6, RS7, and RS8, shunt BAW resonators RP1, RP2, RP3, RP4, and RP5, a shunt inductor L2, and a series output inductor L3. Some or all of the BAW resonators RS1 to RS8 and / or RP1 to RP5 can be incorporated into a BAW component designed in accordance with any suitable principles and advantages disclosed herein. For example, the BAW component 40 of the Fig. 3A or the BAW component 42 of the Fig. 3B all of the BAW resonators of the receive filter 50 have this feature. Any suitable number of series BAW resonators and shunt BAW resonators can be included in a receive filter 50.

[0059] Fig. Figure 6 shows a schematic representation of a high-frequency system 60, which has an acoustic volume wave component according to one embodiment. As shown, the high-frequency system 60 comprises an antenna 62, an antenna switch 64, multiplexers 65 and 66, filters 67 and 68, power amplifiers 70, 72 and 74, and a selector switch 73. The power amplifiers 70, 72 and 74 are each configured to amplify a high-frequency signal. The selector switch 73 can electrically connect an 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 designed in accordance with any suitable principles and advantages disclosed herein. In certain cases, a BAW component can include one or more filters of a multiplexer. Even if the Fig. The multiplexers shown in Figure 6 include a quadplexer and a duplexer. One or more BAW resonators of a BAW component can be included in any other suitable multiplexer, such as a triplexer, a hexaplexer, an octoplexer, or the like. The antenna switch can selectively connect one or more filters and / or one or more multiplexers electrically to the antenna 62.

[0060] The BAW components described herein can be implemented in a variety of packaged modules. These BAW components can occupy less packaged module space than similar modules produced using laser cutting. A packaged module designed to process a high-frequency signal may be referred to as a high-frequency module. Some high-frequency modules are front-end modules. High-frequency modules incorporating a BAW component designed in accordance with any suitable principle and benefit disclosed herein may also include one or more high-frequency amplifiers (e.g., one or more power amplifiers and / or one or more low-noise amplifiers, LNAs), one or more high-frequency switches, and the like, or any suitable combination thereof.Exemplary enclosed modules are now explained in which any suitable principle and benefit of the BAW components disclosed herein can be implemented. Fig. 7 and Fig. Figure 8 shows schematic representations of exemplary enclosed modules according to specific embodiments. Any suitable combination of features from these embodiments can be combined with one another.

[0061] Fig. Figure 7 shows a schematic representation of a high-frequency module 75, which has an acoustic volume wave component 76 according to one embodiment. The high-frequency module 75 shown comprises the BAW component 76 and other circuits 77. The BAW component 76 can have any suitable combination of features of the BAW components disclosed herein. The BAW component 76 can have a BAW chip which includes BAW resonators.

[0062] The in Fig. The BAW component 76 shown in Figure 7 has a filter 78 and terminals 79A and 79B. The filter 78 comprises BAW resonators. The terminals 79A and 79B can, for example, serve as an input contact and an output contact. The BAW component 76 and the other circuits 77 are in Fig. 7 is mounted on a common housing substrate 80. The housing substrate 80 can be a laminate substrate. The terminals 79A and 79B can be electrically connected to contacts 81A and 81B, respectively, on the housing substrate 80 by electrical connectors 82A and 82B. The electrical connectors 82A and 82B can be, for example, solder joints or wire connections. The other circuits 77 can include any suitable type of additional circuitry. For example, the other circuitry can include one or more power amplifiers, one or more high-frequency switches, one or more additional filters, one or more low-noise amplifiers, or the like, or any suitable combination thereof. The high-frequency module 75 can have one or more housing structures to, for example, provide protection and / or simplify the handling of the high-frequency module 75.Such a housing structure can include a potting compound formed over the housing substrate. The potting compound can enclose some or all of the components of the high-frequency module 75.

[0063] Fig. Figure 8 shows a schematic representation of a high-frequency module 84, which has an acoustic volume wave component according to one embodiment. As shown, the high-frequency module 84 comprises duplexers 85A to 85N, corresponding transmit filters 86A1 to 86N1 and corresponding receive filters 86A2 to 86N2, a power amplifier 87, a selector switch 88, and an antenna switch 89. The high-frequency module 84 can have a housing that encloses the elements shown. The elements shown can be mounted on a common housing substrate 80. The housing substrate 80 can, for example, be a laminate substrate.

[0064] The duplexers 85A to 85N can each have two acoustic wave filters coupled to a common node. The two acoustic wave filters can be a transmit filter and a receive filter. As shown, the transmit filter and the receive filter can each be bandpass filters designed to filter a high-frequency signal. One or more of the transmit filters 86A1 to 86N1 can have one or more BAW resonators of a BAW component designed in accordance with any suitable principles and advantages disclosed herein. Likewise, one or more of the receive filters 86A2 to 86N2 can have one or more BAW resonators of a BAW component designed in accordance with any suitable principles and advantages disclosed herein. Fig. As shown in Figure 8 of the Duplexer, any suitable principles and advantages disclosed herein can be implemented in other multiplexers (e.g., quadplexers, hexaplexers, octoplexers, etc.) and / or in switching plexers.

[0065] The power amplifier 87 can amplify a high-frequency signal. The switch 88 shown is a multi-changeover high-frequency switch. The switch 88 can electrically couple an output of the power amplifier 87 to a selected transmit filter from the transmit filters 86A1 to 86N1. In some cases, the switch 88 can electrically couple the output of the power amplifier 87 to more than one of the transmit filters 86A1 to 86N1. The antenna switch 89 can selectively couple a signal from one or more of the duplexers 85A to 85N to an antenna connection ANT. The duplexers 85A to 85N can be assigned to different frequency bands and / or different operating modes (e.g., different power modes, different signal modes, etc.).

[0066] Fig. Figure 9A is a schematic diagram of a wireless communication device 90, which includes filters 93 in a high-frequency front end 92 according to one embodiment. The filters 93 may include BAW resonators of a BAW component according to the suitable principles and advantages discussed here. The wireless communication device 90 may be any suitable wireless communication device. For example, a wireless communication device 90 may be a mobile phone, such as a smartphone. 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 may transmit RF signals provided by the RF front end 92. Such RF signals may include carrier aggregation signals.

[0067] The RF front end 92 can 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-division multiplexing circuits, or any combination thereof. The RF front end 92 can transmit and receive RF signals associated with all suitable communication standards. The filters 93 can include BAW resonators of a BAW component incorporating any suitable combination of features discussed in relation to the embodiments discussed above.

[0068] 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 an RF signal provided by a 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 all suitable baseband processing functions for the wireless communication device 90. The processor 95 can access the memory 96. The memory 96 can store all suitable data for the wireless communication device 90. The user interface 97 can be any suitable user interface, such as a display with touchscreen functionality.

[0069] Fig. Figure 9B is a schematic diagram of a wireless communication device 100, which includes filter 93 in a high-frequency front end 92 and a second filter 103 in a diversity receiver module 102. The wireless communication device 100 is like the wireless communication device 90 of Fig. 9A, except that the wireless communication device 100 also includes diversity receiving features. As in Fig.As shown in Figure 9B, the wireless communication device 100 comprises a diversity antenna 101, a diversity module 102 configured to process signals received from the diversity antenna 101 and including filters 103, and a transceiver 104 connected to both the high-frequency front end 92 and the diversity receiver module 102. The filters 103 may include BAW resonators of a BAW component incorporating any suitable combination of features discussed in relation to all embodiments described above.

[0070] Each of the embodiments described above can be implemented in conjunction with mobile devices such as mobile phones. The principles and advantages of the embodiments can be applied to any system or device, such as any cellular uplink device, that could benefit from any of the embodiments described herein. The teachings presented here apply to a wide variety of systems. Although this disclosure includes some exemplary embodiments, the teachings described herein can be applied to a wide variety of structures. Each of the principles and advantages described herein can be implemented in conjunction with RF circuits configured to process signals with a frequency in the range of approximately 30 kHz to 300 GHz, such as a frequency in the range of approximately 450 MHz to 8.5 GHz.

[0071] Aspects of this disclosure may be implemented in various electronic devices. Examples of such electronic devices include, but are not limited to, consumer electronics products, components of consumer electronics products such as raw chip (die) and / or acoustic wave filter assemblies and / or packaged radio frequency modules, wireless uplink communication devices, wireless communication infrastructure, electronic test equipment, etc.Examples of electronic devices include, but are not limited to, a mobile phone such as a smartphone, a portable computing device such as a smartwatch or earpiece, a telephone, a television, a computer monitor, a computer, a modem, a handheld computer, a laptop, a tablet computer, a personal digital assistant (PDA), a microwave oven, a refrigerator, an automobile, a stereo system, a DVD player, a CD player, a digital music player such as an MP3 player, a radio, a camcorder, a camera, a digital camera, a portable memory chip, a washing machine, a dryer, a washer / dryer, a copier, a fax machine, a scanner, a multifunctional peripheral device, a wristwatch, a clock, etc. Furthermore, electronic devices can also include unfinished products.

Claims

[1] A method (10) for producing isolated acoustic volume wave components (36; 40; 42), comprising: Forming (16) a buffer layer (32) over a silicon substrate (22) an arrangement of acoustic volume wave components (36; 40; 42) to form exposed roads (34) between individual acoustic volume wave components (36; 40; 42); and Plasma cutting (18) of the acoustic volume wave components (36; 40; 42) along the exposed roads (34) in order to isolate the acoustic volume wave components (36; 40; 42), wherein the buffer layer (32) has an etch rate which is over 30 times slower during plasma cutting compared to an etch rate of silicon. [2] The method (10) according to claim 1, wherein each of the isolated acoustic volume wave components (36; 40; 42) has an acoustic volume wave resonator (24), a cap enclosing the acoustic volume wave resonator (24), and the cap has a side wall (23) that is 5 microns or less away from an edge of the silicon substrate (22) of the respective isolated acoustic volume wave component (36; 40; 42). [3] The method (10) according to claim 2, wherein the side wall (23) is located at least 1 micron away from the edge of the silicon substrate (22) of the respective isolated acoustic volume wave component (36; 40; 42). [4] The method (10) according to any one of claims 1 to 3, wherein the plasma cutting includes etching through both the silicon substrate (22) and a cap substrate (21), and the acoustic volume wave component (36; 40; 42) comprises an acoustic volume wave resonator (24) located above the silicon substrate (22) and below the cap substrate (21). [5] The method (10) according to claim 4, wherein the cap substrate (21) is a silicon substrate. [6] The method (10) according to any one of claims 1 to 5, further comprising forming (14) a conductor (28) over the silicon substrate (22), which extends laterally away from a through hole (26) extending through the silicon substrate (22), and which is electrically connected to a conductive layer (27; 43) in the through hole (26). [7] The method (10) according to any one of claims 1 to 6, wherein the formation (16) of the buffer layer (32) comprises forming the exposed roads (34) via a photolithographic process. [8] The method (10) according to any one of claims 1 to 7, wherein the acoustic volume wave components (36; 40; 42) each comprise an acoustic thin-film volume wave resonator. [9] A method (10) for producing isolated acoustic volume wave components (36; 40; 42) which comprises: Providing (12) a first wafer which is connected to a second wafer and on which acoustic volume wave resonators (24) are provided, above which and spaced apart from which the second wafer is located; Forming (16) a buffer layer (32) on one side of the first wafer, which is opposite the acoustic volume wave resonators (24), so that roads (34) are exposed; and Plasma cutting (18) through the first wafer and the second wafer along the exposed roads (34) to form isolated acoustic volume wave components (36; 40; 42), wherein the buffer layer (32) has an etch rate that is over 30 times slower during plasma cutting compared to an etch rate of silicon. [10] The method (10) according to claim 9, wherein the first wafer and the second wafer are silicon wafers. [11] The method (10) according to claim 9 or 10, wherein each of the isolated acoustic volume wave components (36; 40; 42) has an acoustic volume wave resonator (24) of the acoustic volume wave resonators and a cap enclosing the acoustic volume wave resonator (24) which has a side wall (23). [12] The method (10) according to claim 11, wherein the side wall (23) is located in a range between 1 micron and 5 microns away from an edge of a substrate (22) corresponding to a region of the first wafer prior to plasma cutting of the respective isolated acoustic volume wave component (36; 40; 42). [13] A method (10) for producing isolated acoustic volume wave components (36; 40; 42) which comprises: Forming (16) a resin-encompassing buffer layer (32) over a silicon substrate (22) of acoustic volume wave components (36; 40; 42), so that roads (34) are exposed; and Plasma cutting (18) of the acoustic volume wave components (36; 40; 42) along the exposed roads (34) in order to isolate the acoustic volume wave components (36; 40; 42), each of which has an acoustic volume wave resonator (24) and a cap enclosing the acoustic volume wave resonator, which has a silicon cap substrate (21) and a copper-enclosing side wall (23) that is located in a range between 1 micron and 5 microns from an edge of the silicon substrate (22) of the respective isolated acoustic volume wave component (36; 40; 42). [14] The method (10) according to claim 13, wherein the acoustic volume wave resonator (24) is an acoustic thin-film volume wave resonator. [15] An acoustic volume wave component (36; 40; 42), comprising: a substrate (22); at least one acoustic volume wave resonator (24) on the substrate (22); a buffer layer (32) arranged on a side of the substrate (22) opposite the at least one acoustic volume wave resonator (24), and comprising a material with an etch rate that is over 30 times slower during plasma cutting compared to an etch rate of silicon; and a cap enclosing at least one acoustic volume wave resonator (24), which includes a side wall (23) that is spaced 5 microns or less from the edge of the substrate (22). [16] The acoustic volume wave component (36; 40; 42) according to claim 15, wherein the side wall (23) is spaced 3 microns or less from the edge of the substrate (22). [17] The acoustic volume wave component (36; 40; 42) according to claim 15 or 16, wherein the side wall (23) is spaced at least 1 micron from the edge of the substrate (22). [18] The acoustic volume wave component (36; 40; 42) according to one of claims 15 to 17, further comprising a through hole (26) extending through the substrate (22), a conductive layer (27; 43) in the through hole (26), and a part of the resin-comprising buffer layer (32) in the through hole (26). [19] The acoustic volume wave component (36; 40; 42) according to one of claims 15 to 18, further comprising a through hole (26) extending through the substrate (22), a conductor extending laterally away from the through hole (26) and electrically connected to a conductive layer (27; 43) in the through hole (26), and solder material on the conductor arranged laterally next to the through hole (26) such that the solder material does not overlap with the through hole (26). [20] The acoustic volume wave component (36; 40; 42) according to one of claims 15 to 19, wherein the at least one acoustic volume wave resonator (24) comprises an acoustic thin-film volume wave resonator. [21] The acoustic volume wave component (36; 40; 42) according to one of claims 15 to 20, wherein the at least one acoustic volume wave resonator (24) has a fixedly mounted resonator. [22] The acoustic volume wave component (36; 40; 42) according to one of claims 15 to 21, wherein the substrate (22) is a silicon substrate. [23] The acoustic volume wave component (36; 40; 42) according to claim 22, wherein an upper region of the cap is a silicon cap substrate (21). [24] The acoustic volume wave component (36; 40; 42) according to any one of claims 15 to 23, wherein the side wall (23) comprises copper. [25] The acoustic volume wave component (36; 40; 42) according to any one of claims 15 to 24, wherein the at least one acoustic volume wave resonator (24) comprises a plurality of acoustic volume wave resonators arranged in a filter (45; 50; 78; 86A1; 86A2; 86N1; 86N2; 93; 103) for filtering a high-frequency signal. [26] The acoustic volume wave component (36; 40; 42) according to claim 25, wherein the plurality of acoustic volume wave resonators (24) includes at least 10 acoustic volume wave resonators. [27] An acoustic volume wave component (36; 40; 42), comprising: a silicon substrate (22); at least one acoustic volume wave resonator (24) on the silicon substrate (22); a buffer layer (32) arranged on a side of the silicon substrate (22) opposite the at least one acoustic volume wave resonator (24), and comprising a material with an etch rate that is over 30 times slower during plasma cutting compared to the etch rate of silicon; and a cap enclosing at least one acoustic volume wave resonator (24), which has a silicon-containing cap substrate (21) and a side wall (23) which is spaced from an edge of the silicon substrate (22) by a distance in the range between 1 micron and 5 micron. [28] The acoustic volume wave component (36; 40; 42) according to claim 27, further comprising a through hole (26) extending through the silicon substrate (22), a conductive layer (27; 43) in the through hole (26), and a part of the resin-comprising buffer layer (32) in the through hole (26). [29] The acoustic volume wave component (36; 40; 42) according to claim 27, further comprising a through-hole (26) extending through the silicon substrate (22), a conductor which extends laterally from the through-hole (26) and is electrically connected to a conductive layer (27; 43) in the through-hole (26), and solder material on the conductor which is arranged laterally next to the through-hole (26) such that the solder material does not overlap with the through-hole (26). [30] The acoustic volume wave component (36; 40; 42) according to one of claims 27 to 29, wherein the side wall (23) comprises copper. [31] The acoustic volume wave component (36; 40; 42) according to one of claims 27 to 30, wherein the at least one acoustic volume wave resonator (24) comprises at least 10 acoustic volume wave resonators arranged in an acoustic wave filter (45; 50; 78; 86A1; 86A2; 86N1; 86N2; 93; 103) for filtering a high-frequency signal. [32] The acoustic volume wave component (36; 40; 42) according to one of claims 27 to 31, wherein the buffer layer (32) is a phenolic resin layer. [33] A wireless communication device (90; 100) comprising: an antenna (91; 101); and an acoustic volume wave component (36; 40; 42) comprising a substrate (22), acoustic volume wave resonators (24) on the substrate (22), a buffer layer (32) arranged on a side of the substrate (22) opposite the acoustic volume wave resonators (24), and comprising a material with an etch rate that is over 30 times slower during plasma cutting compared to an etch rate of silicon, and a cap enclosing the acoustic volume wave resonators (24), which has a side wall (23) spaced 5 microns or less from an edge of the substrate (22), wherein the acoustic volume wave resonators (24) are arranged in a filter (93; 103) in communicative interaction with the antenna (91; 101). [34] The wireless communication device (90; 100) according to claim 33, wherein the wireless communication device (90; 100) is designed as a mobile phone. [35] The wireless communication device (90; 100) according to claim 33 or 34, further comprising a high-frequency amplifier which is in communicative operative connection with the filter (93; 103) and a switch which is coupled between the filter and the antenna.

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