Stacked acoustic wave (AW) package with reduced reflector wave excitation

Abstract

Aspects of the present disclosure relate to devices, wireless communication apparatuses, methods, and circuits for implementing bulk wave suppression in stacked electroacoustic devices. One aspect includes: a first substrate (420) including a first surface and a second surface, where the second surface is opposite the first surface; a first AW resonator circuit (450), the first AW resonator circuit being positioned on the first surface of the first substrate; a plurality of elements (440, 446, 448), the plurality of elements including a first element (446), where the plurality of elements are positioned on the second surface of the first substrate, and where the first element (446) is aligned with a first AW resonator circuit (450); and a second substrate (430) comprising a first surface and a second surface, where a plurality of elements (440, 446, 448) are positioned on the first surface of the second substrate, and where the plurality of elements create a cavity (421) between the first substrate and the second substrate. A cover substrate (410) having a first surface and a second surface; and a second plurality of elements (440, 442, 444) positioned on the first surface of the first substrate (420) and the second surface of the cover substrate (410) to create a second cavity, where the second cavity is positioned between the first substrate (420) and the cover substrate (410). The plurality of elements (440, 442, 446, 444, 448) may be formed from a metal or polymeric material. A homogeneous polymer layer (458) at the bottom surface of the first substrate (420) may provide increased attenuation to weaken reflector waves (462).

Description

Technical Field

[0001] The present disclosure generally relates to electronic communications and acoustic wave (AW) circuits. For example, aspects of the present disclosure relate to surface acoustic wave (SAW) filter circuits in stacked packages having structures configured to reduce reflected bulk wave excitation within the stacked packages. Background Art

[0002] Electronic devices include traditional computing devices, such as desktop computers, notebook computers, tablet computers, smart phones, wearable devices such as smart watches, Internet servers, etc. These various electronic devices provide information, entertainment, social interaction, security, safety, productivity, transportation, manufacturing and other services for human users. Many functions of these various electronic devices rely on wireless communication. Wireless communication systems and devices are widely deployed to provide various types of communication content, such as voice, video, packet data, message transceiving, broadcasting, etc. These systems can support communication with multiple users by sharing available system resources (e.g., time, frequency and power). Aspects of such systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems and orthogonal frequency division multiple access (OFDMA) systems (e.g., long term evolution (LTE) systems or new radio (NR) systems).

[0003] The wireless communication transceivers used in these electronic devices typically include multiple radio frequency (RF) filters for filtering signals within a specific frequency or frequency range. Electroacoustic devices (e.g., "acoustic filters" or "acoustic wave (AW) filters") are used in many applications to filter signals. Using piezoelectric materials as vibration media, acoustic resonators operate by transforming electrical signal waves propagating along electrical conductors into acoustic waves propagating via piezoelectric materials. Acoustic waves propagate at a speed with a magnitude much smaller than the propagation speed of electromagnetic waves. Generally speaking, the magnitude of the propagation speed of waves is proportional to the size of the wavelength of the waves. Therefore, after converting the electrical signal into an acoustic signal, the wavelength of the acoustic signal wave is significantly smaller than the wavelength of the electrical signal wave. The resulting smaller wavelength of the acoustic signal enables the use of smaller filter devices to perform filtering. Smaller filter devices allow the use of acoustic resonators in electronic devices with size restrictions, such as the electronic devices listed above (e.g., particularly including portable electronic devices, such as cellular phones). However, such AW filters are prone to generating stray waves (e.g., body waves), which can cause signal interference in the device. Reducing the impact of such body waves can improve the operation of the device. Summary of the invention

[0004] Systems, apparatus, methods, and computer-readable media for electronic communications are disclosed, and more particularly, devices, wireless communication devices, and circuits for implementing stacked AW resonator packages configured to attenuate or reduce excitation of bulk waves that can degrade device performance.

[0005] According to at least one example, a device for RF signal filtering is provided. The device includes a stacked acoustic wave (AW) filter package, which includes: a first substrate having a first plurality of AW resonator circuits positioned on a top side; a second substrate having a second plurality of AW resonator circuits positioned on a top side; a frame positioned between the first substrate and the second substrate to create a cavity between a bottom side of the first substrate and a top side of the second substrate; and one or more acoustic reflection suppression structural walls supporting the cavity between the bottom side of the first substrate and the top side of the second substrate, the one or more acoustic reflection suppression structural walls positioned at a selected position on the back side of the first substrate to attenuate a selected acoustic bulk wave path from the first plurality of AW resonator circuits that generates interference in a signal path of the stacked AW filter package.

[0006] In another aspect, a method for filtering a radio frequency (RF) signal is provided. The method includes providing a signal at an interconnect of a stacked acoustic wave (AW) filter package, wherein the interconnect is positioned on a cover substrate; exciting an acoustic wave at a first AW resonator circuit on a first substrate positioned at a stacking layer separate from the cover substrate, wherein the first AW resonator circuit is electrically coupled to the interconnect, and wherein the first AW resonator circuit is positioned within a first cavity supported by an element between the cover substrate and the first substrate; and attenuating a bulk wave from the first AW resonator circuit in the first substrate using a reflection suppression element positioned at a side of the first substrate opposite to the first AW resonator circuit, wherein the reflection suppression element is also positioned to support a second cavity between the first substrate and a second substrate, and wherein the second substrate is at an additional stacking layer separate from both the cover substrate and the first substrate.

[0007] In another aspect, a wireless communication device is provided, comprising: a first substrate, the first substrate comprising a first surface and a second surface, wherein the second surface is opposite to the first surface; a first electroacoustic component, the first electroacoustic component being used to filter a radio frequency signal, wherein the first electroacoustic component is positioned on the first surface of the first substrate; and a component for suppressing acoustic bulk waves, the component for suppressing acoustic bulk waves being located on the second surface of the first substrate.

[0008] According to at least one additional example, an apparatus for RF signal filtering using a stacked AW package with reduced bulk wave excitation is provided. The apparatus includes: a first substrate including a first surface and a second surface, wherein the second surface is opposite to the first surface; a first AW resonator circuit, the first AW resonator circuit being positioned on the first surface of the first substrate; a plurality of elements, the plurality of elements including a first element, wherein the plurality of elements are positioned on the second surface of the first substrate, and wherein the first element is aligned with the first AW resonator circuit; and a second substrate including a first surface and a second surface, wherein the plurality of elements are positioned on the first surface of the second substrate, and wherein the plurality of elements create a cavity between the first substrate and the second substrate.

[0009] In some aspects, the second AW resonator circuit is positioned on the first surface of the second substrate in a cavity between the first substrate and the second substrate.

[0010] In some aspects, the second AW resonator circuit is positioned between the first element and the second element.

[0011] In some aspects, a first plurality of AW resonator circuits are disposed on a first surface of a first substrate, the first plurality of AW resonator circuits including a first AW resonator circuit, and a second plurality of AW resonator circuits are disposed on a first surface of a second substrate, the second plurality of AW resonator circuits including a second AW resonator circuit; wherein the first plurality of AW resonator circuits and the second plurality of AW resonator circuits are each electrically coupled to a corresponding signal path as part of a radio frequency (RF) filter.

[0012] In some aspects, a molding material covering at least a portion of the second surface of the second substrate is provided, wherein the molding material is aligned with a location of the second AW resonator circuit to attenuate reflections of bulk waves entering the second substrate from the second AW resonator circuit.

[0013] In some aspects, a cover substrate having a first surface and a second surface is provided, along with a second plurality of elements positioned on the first surface of the first substrate and the second surface of the cover substrate to create a second cavity, wherein the second cavity is positioned between the first substrate and the cover substrate.

[0014] In some aspects, the plurality of elements include polymer elements and the second plurality of elements include polymer elements.

[0015] In some aspects, the plurality of elements comprises homogeneous metal elements and the second plurality of elements comprises homogeneous metal elements.

[0016] In some aspects, a uniform polymer layer is provided that covers at least a portion of the second surface of the first substrate within a reflected bulk wave path from the first AW resonator circuit through the first substrate.

[0017] In some aspects, the plurality of elements provide structural support to maintain the physical position of the first substrate and the second substrate within the stacked AW filter circuit.

[0018] In some aspects, a polymer frame disposed on a second surface of a first substrate and a first surface of a second substrate is provided, wherein the polymer frame is positioned at an edge portion of the first surface of the second substrate and an edge portion of the second surface of the first substrate to encapsulate a cavity.

[0019] In some aspects, the first element extends from the polymer frame at an edge portion of the first surface of the second substrate into the cavity.

[0020] In some aspects, the first element is positioned within the cavity without being connected to the polymer frame at an edge portion of the first surface of the second substrate or an edge portion of the second surface of the first substrate.

[0021] In some aspects, the first AW resonator circuit includes a plurality of surface acoustic wave (SAW) resonators.

[0022] In some aspects, the first element is aligned with the first AW resonator circuit such that one or more bulk waves enter the first substrate from the first AW resonator circuit at a location between the first AW resonator circuit and the first element.

[0023] In some aspects, the first element is a polymer structural support wall for the first substrate, and the first element is positioned so that one or more bulk waves enter the first substrate from the first AW resonator and are reflected where the second surface of the first substrate contacts the first element.

[0024] In some aspects, the first AW resonator includes an interdigital transducer (IDT) electrode structure positioned on a piezoelectric surface in a first plane parallel to a first surface of a first substrate, wherein the first element contacts a second surface of the first substrate in an acoustic reflection attenuation region of a second plane parallel to the first plane.

[0025] In some aspects, the first element is positioned such that a projection of a region of the IDT electrode structure onto a second plane in a direction perpendicular to the first plane causes the projection at the second plane to overlap with an acoustic reflection attenuation region in the second plane.

[0026] In some aspects, the AW filter device is integrated into a device selected from the group consisting of: a set-top box; an entertainment unit; a navigation device; a communication device; a fixed location data unit; a mobile location data unit; a global positioning system (GPS) device; a mobile phone; a cellular phone; a smart phone; a Session Initiation Protocol (SIP) phone; a tablet computer; a phablet; a server; a computer; a portable computer; a mobile computing device; a wearable computing device; a desktop computer; a personal digital assistant (PDA); a monitor; a computer monitor; a television; a tuner; a radio; a satellite radio; a music player; a digital music player; a portable music player; a digital video player; a video player; a digital video disc (DVD) player; a portable digital video player; an automobile; a vehicle component; an avionics system; a drone; and a multirotor aircraft.

[0027] In some aspects, the AW filter device is integrated into the radio frequency (RF) front-end circuitry of the transceiver.

[0028] In some aspects, a front-end circuit of a transceiver includes a multiplexer (eg, a duplexer) coupled to an antenna, wherein the multiplexer includes a stacked AW filter circuit.

[0029] This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification of this patent, any or all drawings, and each claim.

[0030] The foregoing and other features and embodiments will become more apparent upon reference to the following description, claims and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1A is a diagram of a perspective view of an example of an electroacoustic device;

[0032] Figure 1B yes Figure 1A A diagram of a side view of an electroacoustic device;

[0033] Figure 1C is a diagram illustrating a top view of an example of an electrode structure of an example electroacoustic device;

[0034] Figure 2A is an illustration of a side view of a cross section through ground pins or signal pins of some components of a stacked AW filter package according to aspects described herein;

[0035] Figure 2B is a perspective view of a portion of a stacked AW filter package according to various aspects described herein;

[0036] Figure 3 is a cross-sectional side view of some elements of a stacked AW filter package according to various aspects described herein, illustrating reflected body waves that may occur within the stacked AW filter package;

[0037] Figure 4A is a cross-sectional side view of some elements of a stacked AW filter package modified to reduce excitation of reflected bulk waves that may occur within the stacked AW filter package according to aspects described herein;

[0038] Figure 4B is a cross-sectional side view of some elements of another stacked AW filter package modified to reduce excitation of reflected bulk waves that may occur within the stacked AW filter package according to aspects described herein;

[0039] Figure 5 is a top view showing multiple layers of a stacked AW filter configured to reduce excitation of reflected bulk waves according to various aspects described herein;

[0040] Figure 6 is a graph of transmit signal leakage associated with reflected bulk waves in a stacked AW filter, illustrating reduced excitation of reflected bulk waves in a selected communications band, according to aspects described herein;

[0041] Figure 7 is a flow chart illustrating a method of operation of a stacked AW filter according to examples described herein;

[0042] Figure 8 is a functional block diagram depicting elements of a stacked AW filter according to various aspects described herein.

[0043] Fig. 9 is a block diagram of a wireless communication device including a radio frequency integrated circuit (RFIC) including a stacked AW filter according to aspects described herein;

[0044] Fig.10 is a schematic diagram of a filter that may be implemented using a stacked AW filter according to aspects described herein;

[0045] Fig.11 is a diagram of an environment that includes an electronic device that includes a filter that can be implemented using a stacked AW filter according to the examples described herein. DETAILED DESCRIPTION

[0046] The specific embodiments described below in conjunction with the accompanying drawings are intended as descriptions of exemplary implementations and are not intended to represent the only implementations in which the present invention may be practiced. The term "exemplary" means "serving as an example, example, or illustration" and should not be interpreted as being preferred or superior to other implementations, including the specifically described implementations and any other implementations that are apparent from the specific aspects described herein. The specific embodiments include specific details for the purpose of providing a thorough understanding of the exemplary implementations. In some instances, some devices are shown in block diagram form. Common drawing elements in the following figures may be identified using the same reference numerals.

[0047] Electroacoustic devices (also referred to herein as acoustic wave (AW) resonators) are devices with high-Q performance characteristics at frequencies above several megahertz (MHz) and provide performance that is valuable in many wireless communication devices. While certain performance characteristics of AW resonators are valuable, filter circuits made from AW resonators on piezoelectric substrates with limited thickness to meet device size standards can transmit bulk waves (e.g., bulk waves or other spurious modes can be acoustic wave modes that propagate in a direction different from the direction of an operating wave mode, such as a surface acoustic wave mode, such as in a perpendicular direction) within the substrate on which the resonator circuit is mounted. The bulk waves can travel through the substrate, reflect from the back side, and be sensed by the same AW resonator or other AW resonators (e.g., other acoustic transducers) and circuits, resulting in spurious signals, noise, and reduced device performance.

[0048] In addition, as space and size constraints become more stringent in device designs, stacked substrates can address size constraints but can limit the options for addressing body waves. Stacked substrates can also make body wave problems greater because there is less space for body waves to dissipate over distance. At the outer stack or edges of the device, molding or other packaging can be used to attenuate body waves and limit energy propagation to undesirable locations within the design via reflected body waves. In stacked circuits, the space for attenuation structures is limited, and the internal substrate surfaces are not in contact with the molding material to provide mechanical attenuation to reduce the excitation of reflected body waves. However, stacked circuits do use support structures to maintain the mechanical integrity of the stack.

[0049] According to various aspects described herein, a stacked AW resonator circuit is provided with a frame and wall structure positioned in a specific position to provide a target attenuation of a reflected body wave. The use of the frame and wall structure facilitates the stacking of the AW resonator circuit, and the device performance can be improved by repositioning certain frame and wall structures to attenuate the reflected body wave. For example, such a structure allows a compact stacked packaging of the AW filter circuit while achieving a target attenuation of the reflected body wave to meet the performance target. In some examples, the reflected body wave paths in the design that cause performance target issues can be identified, and limited adjustments to the AW resonator circuit arrangement can be used to reposition or add nearby supports or wall structures, while the reflected body wave paths that do not affect the device performance target can be ignored. Therefore, the various aspects described herein allow for improved device performance with minor adjustments to the position of the circuit and support structure (e.g., polymer wall) to allow for mechanical acoustic stacked AW circuits (e.g., improving performance related to insertion loss or attenuation specific to communication bands) with reduced reflected body wave excitation based on the position of the elements within the stacked AW package. Details related to various aspects of the present disclosure are described in more detail below with reference to the accompanying drawings.

[0050] Figure 1A 1 is a diagram of a perspective view of an example of an electroacoustic device. The electroacoustic device may be configured as a surface acoustic wave (SAW) resonator or a portion thereof. In some descriptions herein, the electroacoustic device 100 may be referred to as a SAW resonator, which may be incorporated into an AW filter (e.g., a stacked AW filter as further described below). However, there may be other types of electroacoustic devices (e.g., AW resonators such as bulk acoustic wave (BAW) or thin film (TFBAR) resonators) that may be constructed based on the principles described herein, and any of them may be incorporated into an AW filter made using an AW resonator (e.g., a SAW resonator, a BAW resonator, or other AW resonator). Although the examples described below specifically relate to SAW resonators, the various aspects described herein may be applicable to other types of AW resonators. In addition to BAW resonators, the AW filter described herein may also include an AW resonator configured within the device to suppress body waves. The BAW resonator uses cross-layer resonance (e.g., compared to the comb structure in a single layer of a SAW resonator). Such BAW resonator structures are less likely to generate additional stray bulk waves, but have different performance characteristics that prevent BAW resonators from being used in place of SAW resonators to improve performance degradation from reflected bulk waves. In some implementations, an AW filter may use a combination of BAW and SAW resonators having a structure as described herein that is configured to reduce noise from bulk waves generated by the SAW resonators in the combined structure.

[0051] The electroacoustic device 100 includes an electrode structure 104, which may be referred to as an interdigital transducer (IDT), located on a surface of a piezoelectric material 102. The electrode structure 104 typically includes a first electrode structure and a second electrode structure (e.g., conductive, typically metallic, tapered), wherein electrode fingers extend from two busbars toward each other and are arranged in an interlocking manner between the two busbars (e.g., arranged in an interdigitated manner). An electrical signal excited in the electrode structure 104 (e.g., application of an AC voltage) is converted into an acoustic wave 106, which propagates in a particular direction through the piezoelectric material 102. The acoustic wave 106 is converted back into an electrical signal and provided as an output. In many applications, the piezoelectric material 102 has a particular crystal orientation such that when the electrode structure 104 is arranged relative to the crystal orientation of the piezoelectric material 102, the acoustic wave propagates primarily in a direction perpendicular to the direction of the fingers (e.g., parallel to the busbars).

[0052] Figure 1B yes Figure 1A The electroacoustic equipment along Figure 1A 1 is a diagram of a side view of a cross-section shown. The electroacoustic device is illustrated by a simplified layer stack that includes a piezoelectric material 102, wherein an electrode structure 104 is disposed on the piezoelectric material 102. The electrode structure 104 is conductive and is typically formed of a metallic material. The piezoelectric material may be formed of a variety of materials such as quartz, lithium tantalate (LiTaO3), lithium niobate (LiNbO3), doped variants of these materials, or other piezoelectric materials. It should be understood that more complex layer stacks (e.g., four (4) layers, six (6) layers, etc.) including layers of various materials are possible within the stack. For example, optionally, a temperature compensation layer 108 (indicated by a dashed line) may be disposed above the electrode structure 104. As another example, the piezoelectric material 102 may be part of a multilayer substrate that may include another base substrate such as a silicon substrate (e.g., for a thin film SAW device, a piezoelectric layer may be formed on a temperature compensation layer, a charge capture layer, a high resistivity layer (e.g., silicon), or other such layer stacks). The piezoelectric material 102 may be extended with a plurality of interconnected electrode structures disposed thereon to form a multi-resonator filter or to provide a plurality of filters. Although not illustrated, when provided as an integrated circuit component, a cover layer may be disposed over the electrode structure 104. The cover layer is applied so that a cavity is formed between the electrode structure 104 and the lower surface of the cover layer. Electrical vias or bumps may also be included to allow the component to be electrically connected to a connector on a substrate (e.g., via a flip chip or other technique).

[0053] Figure 1C is an illustration of a top view of an example of an electro-acoustic device including an electrode structure 104 and an end reflector. Figure 1CA dual-port configuration of an electroacoustic (e.g., AW) device is generally illustrated. An electrode structure 104 has an IDT 105 that includes a first busbar 122 (e.g., a first conductive segment or conductive track) electrically connected to a first terminal 120 and a second busbar 124 (e.g., a second conductive segment or conductive track) spaced apart from the first busbar 122 and connected to a second terminal 130. A plurality of conductive fingers 126 are connected to the first busbar 122 or the second busbar 124 in an interdigitated manner. The fingers 126 connected to the first busbar 122 extend toward the second busbar 124 but are not connected to the second busbar 124, such that a small gap exists between the ends of the fingers 126 and the second busbar 124. Similarly, the fingers 126 connected to the second busbar 124 extend toward the first busbar 122 but are not connected to the first busbar 122, such that a small gap exists between the ends of the fingers 126 and the first busbar 122.

[0054] In the direction along the busbars 122 and 124, there is an overlap region that includes a central region where a portion of one of the fingers overlaps a portion of an adjacent finger (as illustrated by central region 125). The central region 125 including this overlap may be referred to as an aperture, track, or active region where an electric field is generated between the fingers 126 to propagate acoustic waves in the piezoelectric material 102. The periodicity of the fingers 126 is referred to as the pitch of the IDT. The pitch may be indicated in various ways. For example, in some aspects, the pitch may correspond to the size of the distance between the fingers in the central region 125. The distance may be defined as, for example, the distance between the center points of each of the fingers (and when the fingers have a uniform thickness, it may be typically measured between the right (or left) edge of one finger and the right (or left) edge of the adjacent finger). As described herein, a "higher" pitch refers to a section of the IDT where the electrode fingers have a larger distance between adjacent electrode fingers, while a "lower" pitch refers to a section of the IDT where the electrode fingers have a smaller distance between adjacent electrode fingers. In some aspects, an average of the distances between adjacent fingers can be used for the pitch. Giving the electrode fingers in some sections of the IDT a given pitch characteristic that is different from the pitch characteristics of other sections of the IDT will allow selection or control of signals (e.g., waves) propagating through the IDT. The frequency at which the piezoelectric material vibrates is the self-resonance (also called the "primary resonance") frequency of the electrode structure 104. This frequency is determined at least in part by the pitch of the IDT 105 and other characteristics of the electroacoustic device 100.

[0055] In some examples, the pitch characteristic of a segment of an IDT may be a constant pitch, i.e., the pitch does not vary significantly across the IDT segment (e.g., the variation is within manufacturing tolerances and is designed for a constant average pitch). In other examples, the pitch characteristic of an IDT portion may include a "chirped" pitch, i.e., the pitch varies in a predefined manner across the IDT segment. For example, a chirped pitch may include an IDT segment in which the pitch is designed to vary linearly across the IDT segment, such that the pitch at one end of the IDT segment is at a first value, the pitch at the opposite end of the IDT segment is at a second value, and the pitch (e.g., the distance between electrode fingers) varies linearly between the two ends of the IDT segment. In other examples, other nonlinear variations in pitch values ​​across the IDT segment may be used. By combining IDT sections with different pitch characteristics (e.g., a constant pitch at a first value and a constant pitch at a second value, or a constant pitch at a first value in one IDT section and a chirped pitch across a second IDT section), the resonator characteristics can be designed for a given circuit performance, where multiple AW resonators can be combined together to form a filter, as shown below Fig.10 Described in .

[0056] The IDT 105 is arranged between two reflectors 128, which reflect the acoustic waves back toward the IDT 105 so as to convert the acoustic waves into electrical signals via the IDT 105 in the configuration shown and prevent losses (e.g., limit and prevent the acoustic waves from escaping). Each reflector 128 has a grid structure of two busbars and conductive fingers each connected to the two busbars. The pitch of the reflectors can be similar or the same as the pitch of the IDT 105 to reflect the acoustic waves within the resonant frequency range. However, many configurations are possible.

[0057] When converted back to an electrical signal, the measured admittance or reactance between two terminals (eg, first terminal 120 and second terminal 130) serves as a signal for the electro-acoustic device 100 and allows the electro-acoustic device 100 to be used in a signal path as part of a communication device.

[0058] Figure 2A 2 is an illustration of a cross-sectional side view of a stacked AW filter package 200 that includes a first AW resonator circuit 202 (e.g., a SAW resonator circuit as described above) on a first substrate 204 and a second AW resonator circuit 206 on a second substrate 208 to provide electro-acoustic resonators that can be coupled together to form a filter circuit. In some implementations, such AW resonator circuits 202 and 206 can be connected via a redistribution layer and a shared substrate, rather than as shown in FIG. Figure 2A The structure shown in FIG. 2 is on a separate substrate. Each of the first substrate 204 and the second substrate 208 may have a structure similar to Figures 1A to 1CAdditional electro-acoustic devices of the electro-acoustic device 100 (eg, other than the AW resonator circuits 202 and 206) are included as part of the AW filter circuit. Figure 2A 24 is a side view of a cross section of the stacked AW filter package 200 through the ground pad 242 . Figure 2B 246 is a side view of a cross section of the stacked AW filter package 200 through the signal pad 246. In some aspects, the ground pad 242 can be a signal pad and the signal pad 246 can be a ground pad. In other aspects, all combinations of signal pads / ground pads are possible, and Figure 2A and Figure 2B The specific implementation of is an illustrative example of one possible cross section.

[0059] In some implementations, the substrates 204 and 208 may include a piezoelectric layer as part of the described substrate. In other implementations, the AW resonator circuits 202 and 206 may include a piezoelectric layer that may or may not be integrated with the corresponding substrates 204 and 208. In some implementations, the first AW resonator circuit 202 and the second AW resonator circuit 206 may each refer to an electrode structure of a resonator circuit, wherein each electrode structure is positioned relative to a piezoelectric material. The piezoelectric material may be used as a surface for the electrode structure of the AW resonator circuits 202 and 206, and in various aspects, the piezoelectric material may be part of the AW resonator circuit 202 or 206 or part of the corresponding substrate 204, 208.

[0060] like Figure 2A As shown, the AW filter package 200 includes a first AW resonator circuit 202 on a first substrate 204 and a second AW resonator circuit 206 on a second substrate 208. The first AW resonator circuit 202 is stacked on the second AW resonator circuit 206 in a vertical direction (e.g., z-axis direction). The first AW resonator circuit 202 and the second AW resonator circuit 206 are collectively referred to herein as "resonator circuits 202, 206". The first AW resonator circuit 202 and the second AW resonator circuit 206 may each correspond to Figures 1A to 1C AW circuits in the examples, but may also be any other type or configuration of AW filter circuits (e.g., separate or shared filter structures such as Fig.10 Thus, the details of the first AW resonator circuit 202 and the second AW resonator circuit 206 (e.g., the specific AW resonator couplings that form a given filter) are not described in detail. Figure 2A or Figure 2B The resonator circuits 202, 206 include a first metal interconnect (as described above in Figures 1A to 1C), the first metal interconnect is used to receive an input RF signal from an external circuit (e.g., an antenna) and provide a filtered RF signal as an output to the external circuit along a signal path that includes filtering provided by the connection of the AW resonator and other circuit elements.

[0061] exist Figure 2A In the AW filter package 200 in FIG. 2 , the first AW resonator circuit 202 is disposed on a first surface 212 of a first substrate 204. For example, the first substrate 204 may be formed of a semiconductor material (e.g., silicon) formed in a wafer to take advantage of advances in semiconductor processing technology and low costs, wherein the resonator is placed on the piezoelectric material. The second surface 214 is opposite to the first surface 212. In the orientation of the AW filter package 200 shown in FIG. 2 , the first surface 212 may also be referred to as a top surface 212, and the second surface 214 may also be referred to as a bottom surface 214 of the first substrate 204, because the top surface 212 is disposed above the bottom surface 214 in the vertical direction (Z-axis direction).

[0062] The second AW resonator circuit 206 is disposed in or on the third surface 216 of the second substrate 208. In the AW filter package 200, the first substrate 204 is stacked on the second substrate 208 to reduce the area occupied by the AW filter circuits on the first substrate 204 and the second substrate 208. For example, the second substrate 208 (e.g., when a carrier material) may also be formed of a semiconductor material (e.g., silicon) formed in a wafer to take advantage of the advancement and low cost of semiconductor processing technology, wherein the AW resonator is placed on the piezoelectric material, as mentioned above. In this regard, the first substrate 204 may be stacked on the second substrate 208 (e.g., stacked above it in the vertical Z-axis direction), or the second substrate 208 may be stacked on the first substrate 204 (e.g., stacked below it in the vertical Z-axis direction). The frame 218 is disposed between the second surface 214 of the first substrate 204 and the surface 216 of the second substrate 208. The frame 218 can be a polymer support structure configured around the edges of the substrates 204 and 208, wherein the frame creates a cavity 220 in which the AW resonator and other circuits are positioned. The polymer element is configured to prevent the AW resonator circuit or other elements (e.g., the AW resonator circuit 206) in the cavity from contacting the substrate at the top of the corresponding cavity. The frame 218 can provide both mechanical support for the relative positioning of the first substrate 204 and the second substrate 208, and structural protection within the cavity 220 for the elements (e.g., the AV resonator) within the cavity 220. The second AW resonator circuit 206 is disposed in the cavity 220 between the bottom surface 214 of the first substrate 204 and the top surface 216 of the second substrate 208. The cavity 220 can also include air or a gas.

[0063] Figure 2A The AW filter package 200 in the embodiment also includes a cover substrate 222 disposed on the first surface 212 of the first substrate 204. The cover substrate 222 is separated from the first surface 212 by the frame 218 to form a cavity 226, in which the first AW resonator circuit 202 is disposed. The cover substrate 222 provides a cover for the cavity 226 in the same manner as the first substrate 204 provides a cover for the cavity 220. The cavity 226 also includes air or another gas surrounding the first AW resonator circuit 202. The cover substrate 222 can be, for example, glass or another non-conductive substrate material. The stacked AW filter package 200 also includes contacts 228A, 228B (e.g., Figure 2B 2 (shown in FIG. 2 ), these contacts are disposed on metal interconnects 230A, 230B on a contact surface 232 of the cover substrate 222 for connecting the second AW resonator circuit 206 to an external circuit. The contacts 228A, 228B are coupled to the second AW resonator circuit 206 through metal interconnects 230A, 230B formed in a metallization (redistribution) layer 236. The metallization layer 236 extends from the contact surface 232 onto a side surface 238 of the cover substrate 222 and onto a side surface 240 of the first substrate 204. The side surface 240 extends between the first surface 212 and the second surface 214 of the first substrate 204. Additional contacts (not shown) may be disposed on the contact surface 232 for connecting the first AW resonator circuit 202 to an external circuit (e.g., a processing circuit, an antenna, etc.).

[0064] exist Figure 2A In the stacked AW filter package 200 in FIG. 2 , the first AW resonator circuit 202 may filter a first RF signal, while the second AW resonator circuit 206 may filter another RF signal. In other aspects, the first AW resonator circuit 202 and the second AW resonator circuit 206 may filter the same signal (e.g., using resonators in the same ladder network). In addition, as described above, each AW resonator circuit 202, 206 may include one or more resonators connected in one or more filter circuits, depending on the device configuration for filtering RF signals in the communication device. In some examples, the resonator circuits 202, 206 are not electrically associated with each other in operation, but in other examples, both resonator circuits 202, 206 may be coupled to the same antenna (not shown) that is coupled to the AW filter package 200. Therefore, the resonator circuits 202, 206 may provide different filters for the same RF signal, or may filter different RF signals.

[0065] In various implementations, due to design factors (e.g., due to device size constraints), the resonator circuits 202, 206 may be in close proximity to each other or to other AW resonators or other circuit elements in the AW filter package 200, such that noise generated from bulk waves in the first AW resonator circuit 202 may interfere with the operation of the first AW resonator circuit 202 and the operation of the second AW resonator circuit 206. Similarly, noise generated in the second AW resonator circuit 206 may interfere with itself and interfere with the signal of the first AW resonator circuit 202. This noise from reflected bulk waves may have a greater impact when the first AW resonator circuit 202 and the second AW resonator circuit 206 are coupled to the same antenna. As described below with respect to Figure 5 Further describing, in some aspects, a design can be formed with certain AW resonators or resonator circuits positioned to have an expected amount of noise from reflected body waves. The attenuation structures described herein can be used as needed to meet performance goals, and if the amount of noise does not cause the design to fail to meet performance goals, the attenuation structures described herein can be not used even when reflected body waves are present.

[0066] As described herein, portions of the frame 218, additional support walls 224, or other such support structures may be used not only for mechanical stability and support, but also for attenuating reflected body waves. Furthermore, in some elements, such support elements may be combined with additional attenuation layers, such as polymer or metal attenuation layers, that may attenuate reflected body waves. In other aspects further described below, uniform or structured polymer or metal layers may be used in addition to attenuation from supporting frame structures (such as the frame 218 or walls 224). In some aspects, a metal layer is included to operate as an electromagnetic shield (e.g., a Faraday shield) and block propagation of reflected body waves (e.g., interference signals that generate noise) between adjacent circuits.

[0067] Figure 2B yes Figure 2A A perspective view of the AW filter package 200 is shown in FIG. Figure 2B To more clearly illustrate certain aspects of the AW filter package 200, particularly the conductive (eg, metal) interconnects 230A, 230B on the side surface 240 of the first substrate 204. Figure 3 4 illustrates a side perspective view of an AW filter package, but FIG. 2A to FIG. 2B Details available for Figure 3 and the configuration of FIG. 4 , wherein the adjustments to the positioning of the electroacoustic resonator and the attenuation structure discussed below are consistent with FIG. 2A to FIG. 2B206. The metal interconnect 230A is integrated with the additional details described in . As shown in this non-limiting example, the metal interconnect 230A extends from the contact 228A and is disposed on the side surface 238 of the cover substrate 222, on the frame 218, on the first surface 212 of the first substrate 204, and can be coupled to a portion 244 of the signal path, which is used to form a filter with the AW resonator (e.g., resonator circuits 202, 206). The metal interconnect 230A couples a portion of the signal path or the ground path to a corresponding element of the circuit (e.g., coupling the second AW resonator circuit 206 to the contact 228A). For example, the contact 228A can receive a ground voltage source V from an external circuit in the mobile device. SS The metal interconnect 230B extends from the contact 228B and is disposed on the side surface 238 of the cover substrate 222, the insulating layer 248, the frame 218, and the signal pad 246. The metal interconnect 230B couples the signal pad 246 of the AW resonator circuit 206 to the contact 228B, which may be coupled to at least one of the first AW resonator circuit 202 and an external circuit.

[0068] Figure 3 is a cross-sectional side view of some elements of the stacked AW filter package 300 illustrating reflected bulk waves (eg, bulk waves 362 and 364 ) that may occur within the stacked AW filter package 300 according to various aspects described herein. Figure 3 The cross section of FIG. 3 illustrates an edge portion of the stacked AW filter package 300 on the left and a center portion on the right, which may be continuous with an additional AW resonator circuit and a wall, as shown below in FIG. Figure 5 . Although the upper cavity 370 is shown as having only a single AW resonator circuit 350 and the lower cavity 380 is shown as having two AW resonator circuits 352 and 354, the complete stack of layers not shown may have additional AW resonator circuits at different locations not shown (e.g., at different depths of the slice, or further along the slice to the right in an unshown section of the stacked AW filter package 300). As noted above, the AW resonator circuits 350, 352, and 354 include the same Figure 1A , Figure 1B and Figure 1CIn various implementations, the AW resonator circuits 350, 352, and 354 may include a piezoelectric surface on which the corresponding electrode structure is positioned, or the electrode structure may be positioned on a piezoelectric layer that is part of a corresponding substrate (e.g., substrates 320 and 330) of each AW resonator circuit 350, 352, 354. In addition, in some implementations, each AW resonator circuit 350, 352, 354 may include electrode structures for multiple SAW resonators, as well as internal and external signal connections associated with a specific configuration of the SAW resonators of the associated AW filter.

[0069] and Figure 2A and Figure 2B Compared with the details, Figure 3 The portions of the stacked AW filter package 300 shown in FIG. 3 are simplified, but may include additional elements as described above, or other elements as part of integration with other elements of the device. Figure 3 The example includes two stacked substrates (e.g., first substrate 320 and second substrate 330) with a third cover substrate (e.g., cover substrate 310) on top. Cover substrate 310 has a connector 302 positioned on the top surface, with electrical connections extending down the sides of stacked AW filter package 300 to allow electrical connections to AW resonator circuit 352. Figure 2B As shown, other parts of the stacked AW filter package 300 may include additional connections with electrical paths connecting them to different AW resonator circuits. The first substrate 320 has a first AW resonator circuit 350 mounted to a first (e.g., top) surface and a plurality of polymer elements 340, 342, and 344. As described in further detail below, the polymer element can be part of a frame structure (e.g., element 340) that supports the connection of the stacked layers at the edge of the substrate. Other such polymer elements can be walls extending from the edge frame structure into the central region. Still other polymer elements can be "islands" that float between the two substrates without connections to other polymer walls or frame elements. The support elements are referred to as polymer elements, polymer walls, and / or polymer frames, but can be any suitable substance or structure in other designs that provide the benefits described herein. These polymer elements provide mechanical support for the cavity 370 between the cover substrate 310 and the first substrate 320 in which the first AW resonator circuit 350 is located. The first AW resonator circuit 350 is disposed on the first surface of the first substrate 320 and does not contact the cover substrate 310. The cover substrate is held over the first AW resonator circuit by polymer elements (eg, frame element 340 and wall elements 342 and 344).

[0070] In addition to the first substrate 320, there is a second substrate 330. The AW resonator circuits 352 and 354 are on a first (e.g., top) surface of the second substrate 330, within a second cavity 380 supported by polymer elements 340, 346, and 348 that are also on the top surface of the second substrate 330. The first substrate 320 is part of an inner stacked layer, wherein the top and bottom surfaces of the first substrate 320 are not significantly exposed to the exterior of the stacked AW filter package 300. As described above, this limits exposure to possible acoustic attenuation structures (e.g., molded structures not shown) that may, for example, surround the illustrated portion of the stacked AW filter package 300 or provide a cover for at least a portion of the outer stacked substrate to provide attenuation of reflected body waves such as the reflected body waves 364 in the second substrate 330.

[0071] The illustrated structure implementing a surface acoustic wave (SAW) filter includes wave modes concentrated at the surface of a piezoelectric substrate, as described above with respect to Figures 1A to 1C Such resonators also include unintended bulk wave propagation beyond the surface of the piezoelectric substrate. Such waves can propagate into the bulk of the piezoelectric material and the substrate supporting the resonator element shown (e.g., acoustic signals entering the substrate from a resonator element such as IDT 105, etc.). Propagation into the substrate is a parasitic effect that degrades the overall filter performance (e.g., through increased losses in the carrier aggregation anti-band, higher signal leakage, etc., as shown in FIG. Figure 6 ). Such body waves may further reflect from the back side of the substrate and propagate to other parts of the circuit where other electroacoustic transducers are located by repeated reflections. Although each reflection may reduce the intensity of the body waves, some designs may be sensitive to such body waves sensed by other transducers, and when the body waves are sensed by such transducers and converted back from mechanical (e.g., acoustic) vibrations to electrical signals, the body waves cause crosstalk and noise. These electrical signals are superimposed on the desired filter characteristics of the filter including the receiving transducer and appear as unwanted features in the transmission characteristics of a given filter (e.g., as a spike above the passband frequency, or additional signal leakage). For larger (e.g., longer) AW resonators, the effect becomes more significant due to the possibility of volume waves being reflected back into the acoustically active area within a single transducer (e.g., as opposed to shorter transducers). Some SAW transducers are composed of many sub-transducers, which results in a large effective area that is susceptible to unwanted body reflection signals.

[0072] Figure 3 Also shown are reflected body waves 362 and 364. Figure 1AAs described in FIG. C, AW resonator circuits 350, 352, and 354 include transducers that resonate as an electroacoustic device. Such resonances do not strictly stay within the stack plane (e.g., at the surface of a substrate with a defined electrical path), but rather include some resonances that transmit acoustic (e.g., mechanical) energy into a bulk transmission path as shown. Although body waves 362 and 364 are shown as being close to the AW resonator circuits that generate them (e.g., AW resonator circuit 350 that generates reflected body wave 362 and AW resonator circuit 354 that generates reflected body wave 364), such waves continue throughout the substrate even when they dissipate. As described in detail above, each of the AW resonator circuits 350, 352, 354 may include multiple transducers, and body reflections that bounce back to the AW resonator circuit from the back side of the substrate on which the AW resonator circuit is mounted may degrade performance. Whether the amount of energy from the reflected body wave 364 affects device performance depends on how the signal dissipates and how strong it is. As mentioned above, the reflected body wave 364 at the outer stacked layers can be dissipated by mechanical attenuation from the molded structure or other attenuating material at the second (e.g., bottom) surface of the second substrate 330. Such attenuating material can be SiO2, other such polymer materials, or other materials selected for attenuation properties. However, the reflected body wave 362 does not have any exposure to such surrounding molded structures or any other such attenuating structures, but can be reflected from the surface (e.g., the bottom surface of the substrate 320) that forms or encloses the first cavity 370 and the second cavity 380. Such cavities are unlikely to provide much attenuation, so the reflected body wave 362 in the middle layer of the stack will propagate further and have greater energy when it is received in an undesirable active position of any resonator circuit. Even so, in some structures, the unattenuated reflected body wave 362 may not affect performance, either because the distance to the susceptible AW resonator circuit is far enough that the energy is fully dissipated without added attenuation, or because the circuit design is resilient to such crosstalk. However, other designs may have greater performance constraints (e.g., greater sensitivity targets), or other relevant criteria that require less crosstalk from such mid-level reflector waves in the stack.

[0073] If the electroacoustic filter is part of a multiplexer and these parasitic modes appear in the frequency range of any carrier aggregation anti-band, the performance of the anti-band is degraded and the isolation, attenuation, or leakage performance targets may be affected. If a molding material or any other such attenuation material is applied to the back side of the substrate material used for packaging, the excitation of the reflected bulk wave can be reduced by a mechanical attenuation effect. For example, this can be observed in an electroacoustic SAW filter combined with a thin film acoustic package (TFAP), where the molding material is in direct contact with the back side of the substrate material. The various aspects described herein may include a back-end technology in which there are two or more substrates, each substrate containing one or more electroacoustic filters, which are vertically stacked on top of each other, and reflection of the bulk wave will occur for all filters on all stacked substrates. However, in a molding environment, only the back side of the bottom substrate (e.g., the second substrate 330) will be in direct mechanical contact with the molding material, and the back sides of the other substrates (e.g., the first substrate 320) will not have any contact with the molding material. Therefore, the spurious wave mode excited due to the reflected bulk wave is reduced only for the bottom substrate in contact with the molding material. In some implementations, structural elements such as molding materials may be initially designed without consideration of attenuation effects. Subsequent design modifications to the effects of reflected body waves on device performance may result in adjustments to molding material placement, adjustment of material type to a different attenuating material based on attenuation characteristics, or addition of additional attenuating structures. In some aspects, the design may not include molding material for encapsulation, and attenuating material may be added to improve device performance by reducing degradation from reflected body waves as described herein.

[0074] Figure 4A is a cross-sectional side view of some elements of a stacked AW filter package 400 modified to reduce excitation of reflected bulk waves that may occur within the stacked AW filter package 400 according to various aspects described herein. Figure 4A Included with Figure 34. The illustrated elements include a cover substrate 410, a first substrate 420, and a second substrate 430. The cover substrate 410 supports the connector 402. The first substrate 420 and the cover substrate 410 are separated by a first cavity 411 formed by a polymer element (including a frame element 440 and wall elements 442 and 444). The first AW resonator circuit 450 is positioned on the top surface of the first substrate 420 and is positioned in the first cavity 411. The first substrate 420 and the second substrate 430 are separated by polymer elements 440, 446 and 448 (e.g., having a thickness 447 forming the cavity 421, the thickness 447 being determined by the corresponding thickness of the polymer element that provides mechanical stability to the cavity as part of the structural support of the substrate position) forming the second cavity 430, wherein two AW resonator circuits 452 and 454 are in the second cavity 421 and on the top surface of the second substrate 421. Although the cavities are shown as having a relatively constant thickness, various implementations may involve substrates having different geometries and different cavity thicknesses associated with different polymer elements at different locations within the same cavity.

[0075] However, with Figure 3 Compared to the stacked AW filter package 300 of FIG. 4 , the polymer element 442 and the first AW resonator circuit 450 are shifted to the left, and the polymer element 446 is aligned oppositely to the first AW resonator circuit 450. The opposite alignment refers to the positioning 470 of the first AW resonator circuit 450 directly through the structure of the first substrate 420 to the position of the polymer element 446 on the opposite surface of the first substrate 420. The positioning 470 of the first AW resonator circuit 450 opposite to the polymer element 446 results in the reflected bulk wave 462 having maximum energy at locations in the first substrate 420 where the bulk wave is reflected off at the interface at the second (e.g., bottom) surface of the first substrate 420 where the interface is with the polymer element 446 rather than with the air or gas filled portion of the cavity 421. Such a position 470 of the polymer element 446 results in the energy of the bulk wave being fully or partially absorbed by the polymer element 446 acting as a mechanical attenuation layer. Therefore, the energy of the reflected bulk wave 462 propagating to other portions of the first substrate 420 (in the same or other AW resonators), where the reflected bulk wave may generate crosstalk and interference, is reduced.

[0076] In some implementations, the structure of the stacked AW filter package 400 can be described as including electrode structures in the AW resonator circuits 450, 452, 454, where these electrode structures are located in the xy plane (e.g., approximately parallel to the planar surfaces of the substrates 420 and 430). The resonator is configured to generate an acoustic wave as part of a signal path having a direction in the xy plane via the electrode structure. The AW resonator circuit can generate an undesired bulk acoustic wave having a z-direction component (e.g., outside the xy plane including the electrode structure and into the substrate supporting the electrode structure). The undesired bulk acoustic wave having a z-direction component (e.g., in addition to any x- or y-direction components) can be reflected from the back side of the substrate and interfere with the AW component (e.g., the AW resonator generating the bulk wave, or another AW resonator within the stacked AW filter package 400). In order to suppress such bulk waves, the back side of the substrate where the bulk wave acoustic reflection occurs can be configured with a polymer, metal, or other material interface to suppress the acoustic reflection of the bulk wave (e.g., the acoustic wave having the z-direction component). Such attenuating material may be positioned in the xy plane, offset in the z direction from the AW resonator generating the bulk acoustic wave, at the portion of the backside surface of the substrate where reflection occurs. In other implementations, any interface shape between the backside of the substrate and the attenuating material (e.g., polymer, metal, etc.) that attenuates reflection of the bulk acoustic wave may be used. Such attenuating material may additionally provide structural (e.g., mechanical) stability or other support to the substrate, or may be positioned for acoustic reflection attenuation without providing structural support.

[0077] Figure 4B is a cross-sectional side view of some elements of another stacked AW filter package 401 modified to reduce excitation of reflected bulk waves that may occur within the stacked AW filter package 401 according to various aspects described herein. Figure 4B The structure and Figure 4A The only difference between the AW filter package 400 with the AW filter package 401 is the uniform polymer layer 458. This uniform polymer layer 458 can be manufactured using the same process as the structural polymer elements 440, 446 and 448 as part of the stacked AW filter package 401. Figure 4A and Figure 4B 458. In other embodiments, such an element may be metallic or part of a metallic layer. Adding a uniform polymer layer 458 at the bottom surface of the first substrate may provide increased attenuation to weaken reflected body waves 462 compared to reflections off the interface with the air or gas of the cavity 421. Aspects having such an element may utilize an in-situ manufacturing process to add a small amount of additional material at the bottom surface of the first substrate, thereby reducing crosstalk at a small cost in size (e.g., increased thickness) and material cost (e.g., increased mass). Additionally, although Figure 4B The use of shared polymer materials and processes is illustrated, but some implementations may use different materials for increased attenuation, or for different electrical characteristics.

[0078] Figure 4B A uniform polymer layer and realigned polymer walls are shown. In some implementations, if a uniform polymer layer is applied, realignment of the polymer elements with the resonator structure may not be used, resulting in a uniform polymer layer without realignment of the polymer elements to suppress the bulk acoustic waves, such as Figure 3 as shown in .

[0079] The design of the polymer frame structure including considerations for attenuation of reflected body waves can therefore be further used for additional mechanical stability and attenuation from alignment of the AW resonator circuit with the polymer element. This attenuation can be used for the internal stacked substrate, similar to the attenuation received by the external substrate from the molded material or other attenuation materials as described above. Although the alignment of the polymer walls provides excellent mechanical stability, the various aspects described herein can provide sufficient stability while providing attenuation for the internal stacked layer AW resonator circuit. A small positioning shift of a given design to readjust the position of a dedicated polymer wall can provide a low-cost design adjustment that provides performance improvements to reduce the excitation of reflected body waves. In addition, by directing the movement of the polymer wall to the device element that has a key impact on the performance of the device, and positioning other polymer walls for stability (e.g., aligned with other polymer walls instead of aligned with the AW resonator circuit for attenuation), the mechanical stability target can be maintained while improving electrical performance. In addition, in some aspects, if the displacement of other polymer walls to a position below the AW resonator (e.g., or to any position for suppressing acoustic body wave reflections) degrades the mechanical stability, additional walls (e.g., polymer, uniform metal layer, etc.) can be newly added.

[0080] Thus, the various aspects described herein can improve the electrical performance of stacked AW filter package characteristics such as attenuation, isolation, and transmit leakage in the inverted band while maintaining mechanical stability. Such electrical performance parameters are benefited without corresponding electrical performance tradeoffs, so that such polymer wall adjustments can be made without worrying about corresponding degradation in another part of the electrical design. In addition, because this approach is size neutral with respect to the external package, and an in-situ manufacturing process (e.g., such as Figure 4A The change in wall position shown uses existing technology, while Figure 4B The additional layers shown use new manufacturing steps), so electrical performance can be improved with minimal impact on manufacturing resource usage (eg, cost).

[0081] Figure 5is a top view showing multiple layers of a stacked AW filter package 500 configured to reduce excitation of reflected bulk waves according to various aspects described herein. As mentioned above, the previous illustrations are side cross-sectional views. FIG. 2A to FIG. 2B , Figure 3 , Figure 4 and Figure 5 Each of has a shared directional indication, wherein the plane of the substrate stack is in a constant YX plane, and Figure 2A , Figure 3 and the cross-sectional view of FIG4 is in the XZ plane. Figure 5 A top view in the XY plane is shown, where AW resonator circuits 550, 552, and 554 are mounted on the top surface of a first substrate (not shown, similar to first substrates 320 and 420), multiple different types of polymer elements are mounted on the top surface of a second substrate (e.g., similar to substrates 330 and 430 shown in black), and a cavity 526 constitutes the space around the polymer elements and the AW resonator circuit 550. As shown, the polymer element includes a frame element 510 that constitutes the boundary edge of the cavity 526. Polymer walls 512 and 514 extend from the frame element 510, providing additional mechanical stability. In various implementations, the polymer walls 512 and 514 may be implemented as elements that may not be considered "walls" and may not be polymers. In some implementations, elements of uniform or structured metal layers may be used instead of polymer walls 512 and 514. In some implementations, the polymer walls 512 and 514 may be implemented as non-structural polymer or metal elements within the AW resonator.

[0082] In addition to providing mechanical support in the gap of the cavity 526, the polymer wall 514 is positioned opposite the AW resonator circuit 552, which overlaps the polymer wall 514 from a top-down perspective (e.g., the projection of the AW resonator circuit 552 or the IDT of the AW resonator circuit on the back surface of the substrate overlaps the interface / coupling region of the polymer wall 514 and the substrate). The overlap represents the positioning of the polymer wall 514 on the bottom surface of the first substrate, opposite the AW resonator circuit 552 on the top surface of the first substrate. The position of the polymer wall 514 provides attenuation for reflected body waves launched into the first substrate by the AW resonator circuit 552. The polymer island 516 provides similar attenuation for reflected body waves from the AW resonator circuit 554.

[0083] As shown, only the AW resonator circuits 552 and 554 are aligned relative to the polymer elements (e.g., polymer wall 514 and polymer island 516, respectively). This configuration may be the result of a particular device performance criterion, where signals from the AW resonator circuits 552 and 554 cause interference to themselves or other AW resonator circuits 550, 552, 554. The AW resonator circuit 550 may generate similar reflected body waves without any impact on the performance criterion. Thus, the device may achieve performance goals without polymer elements such as polymer wall 514 and polymer island 516 (e.g., these elements may be metal layers in other specific implementations). In some designs where each AW resonator circuit 550, 552, and 554 has an associated reflected body wave that causes performance issues, or in an initial conservative design where an additional polymer structure provides desired structural support, each of the AW resonator circuits 550 may have an associated polymer island or polymer wall to provide attenuation. Similarly, including or excluding a thin uniform attenuating layer or a partially thin attenuating layer on some or all of the bottom portion of the first substrate (e.g., similar to Figure 4B Although such a layer is not included in the stacked AW filter package 500, other implementations may use such a layer made of any suitable material.

[0084] Additionally, while aspects described herein discuss a single center layer (e.g., a first substrate) in a three-substrate stack, other implementations may use additional stacks, with each stacked layer having an attenuation structure aligned with an AW resonator circuit, depending on the specific performance criteria of a given design and the specific manufacturing process for that design. Such stacking adjustments may be additionally applied to layer 458 (e.g., which may be a polymer or a metal).

[0085] Figure 6600 is a diagram showing the transmit signal leakage associated with the reflector wave in the stacked AW filter package. The diagram 600 illustrates the effect of the reflector wave in the communication anti-band in terms of how much unwanted signal leaks into the anti-band. The signal data 610 corresponds to the stacked AW filter package without backside attenuation. The signal data 620 corresponds to the stacked AW filter package with backside attenuation. The TX leakage in decibel-milliwatt (dBm) is plotted across the communication band 640, where the difference 630 illustrates the reduction of the leakage signal of the design with backside attenuation compared to the design without backside attenuation. As shown in the figure, the use of polymer elements or any other materials that are positioned not only for support but also for attenuation of the reflector wave or cause the excitation of the reflector wave to be reduced can provide a reduction in Tx leakage and associated noise. During the device design, different performance effects at different frequencies can be tested to balance the performance metrics for additional material quality, manufacturing steps and mechanical support standards.

[0086] Figure 7 is an example of a disclosed stacked AW filter (e.g., Figure 4A and Figure 4B Stacked AW filter package 400, Figure 5 The stacked AW filter package 500 has Figure 6 620 in the diagram of the transmit (TX) leakage data 620 exemplified by the stacked AW filter (or the like) of the operation of the method 700 (or process). The method 700 is described in the form of a set of boxes that specify the operations that can be performed. However, the operations are not necessarily limited to Figure 7 , or described herein, as these operations may be performed in an alternative order or in a fully or partially overlapping manner. In addition, more, fewer, and / or different operations may be implemented to perform method 700 or an alternative method. In some implementations, method 700 may be implemented by a control or processing circuit of a wireless device (e.g., electronic device 1102) that configures the operation of the stacked AW filter. In some implementations, method 700 may be implemented as instructions stored in a non-transitory computer-readable storage medium that, when executed by one or more processors of the device, causes the device to perform the operations of method 700.

[0087] At block 702, method 700 includes an operation for providing a signal at an interconnect of a stacked acoustic wave (AW) filter package, wherein the interconnect is positioned on a cover substrate. The signal may be provided according to any aspect described herein and may be provided as a wireless link (e.g., as described below in Fig.11 A wireless communication signal that is part of the wireless link 1106) described in .

[0088] At block 704, method 700 includes an operation for exciting an acoustic wave at a first AW resonator circuit on a first substrate positioned at a stacked layer separated from a cover substrate, wherein the first AW resonator circuit is electrically coupled to the interconnect, and wherein the first AW resonator circuit is positioned within a first cavity supported by an element between the cover substrate and the first substrate. Such an AW resonator circuit may be a circuit comprising a first AW resonator circuit according to the above aspects (e.g., Figure 1A , Figure 1B , Figure 1C etc.) described in detail.

[0089] At block 706, the method 700 includes operations for attenuating bulk waves from the first AW resonator circuit in the first substrate using a reflection suppression element positioned at a side of the first substrate opposite the first AW resonator circuit, wherein the reflection suppression element is also positioned to support a second cavity between the first substrate and a second substrate, and wherein the second substrate is at an additional stacked layer separated from both the cover substrate and the first substrate.

[0090] Figure 8 8 is a functional block diagram of an apparatus 800 including a stacked AW filter as described herein. The apparatus 800 includes a first substrate 802 having a first surface and a second surface, wherein the second surface is opposite to the first surface.

[0091] The device 800 further comprises an electro-acoustic component 804 for filtering radio frequency signals, wherein the electro-acoustic component for filtering radio frequency signals is positioned on the first surface of the first substrate. Such an electro-acoustic component 804 can be configured according to any aspect described herein.

[0092] The device 800 also includes a component 806 for suppressing bulk acoustic waves at the second surface of the first substrate. Such a device 806 can be configured according to any aspect described herein.

[0093] In some aspects, component 806 can also be configured as a component for providing mechanical stability or additional structural support to first substrate 802 .

[0094] Some aspects may also include means for transmitting and / or receiving a radio frequency signal, means for transmitting and / or receiving additional radio frequency signals, and means for processing radio frequency signals (including the radio frequency signal and the additional radio frequency signals).

[0095] Fig. 9A wireless communication device 900 is illustrated that includes an RF component formed by one or more ICs 902 and may include a stacked AW filter package 903. The stacked AW filter package 903 includes a first AW filter circuit disposed on a first substrate, a second AW filter circuit disposed on a second substrate, and an element (e.g., a polymer or uniform metal) that may be structural or non-structural for suppressing bulk acoustic wave reflections that may degrade performance as described herein. As an example, the wireless communication device 900 may include or be disposed in any of the above-described devices. Fig. 9 As shown, the wireless communication device 900 includes a transceiver 904 and a data processor 906 (e.g., a processing circuit). The data processor 906 may include a memory for storing data and program codes. The transceiver 904 includes a transmitter 908 and a receiver 910 that support two-way communication. In general, the wireless communication device 900 may include any number of transmitters 908 and / or receivers 910 for any number of communication systems and frequency bands. All or part of the transceiver 904 may be implemented on one or more analog ICs, RFICs, mixed signal ICs, etc.

[0096] The transmitter 908 or the receiver 910 may be implemented using a superheterodyne architecture or a direct conversion architecture. In a superheterodyne architecture, the signal is converted between RF and baseband in multiple stages, such as from RF to an intermediate frequency (IF) in one stage and then from IF to baseband in another stage. In a direct conversion architecture, the signal is converted between RF and baseband in one stage. Superheterodyne and direct conversion architectures may use different circuit blocks and / or have different requirements. Fig. 9 In the wireless communication device 900 in FIG. 1 , the transmitter 908 and the receiver 910 are implemented using a direct conversion architecture.

[0097] In the transmit path, the data processor 906 processes the data to be transmitted and provides I and Q analog output signals to the transmitter 908. In the wireless communication device 900, the data processor 906 includes digital-to-analog converters (DACs) 912(1), 912(2) to convert the digital signals generated by the data processor 906 into I and Q analog output signals (e.g., I and Q output currents) for further processing.

[0098] Within the transmitter 908, low pass filters 914(1), 914(2) filter the I and Q analog output signals, respectively, to remove undesired signals caused by the preceding digital-to-analog conversion. Amplifiers (AMPs) 916(1), 916(2) amplify the signals from the low pass filters 914(1), 914(2), respectively, and provide I and Q baseband signals. An up converter 918 upconverts the I and Q baseband signals with I and Q TX LO signals from a transmit (TX) local oscillator (LO) signal generator 922 via mixers 920(1), 920(2) to provide upconverted signals 924. A filter 926 filters the upconverted signals 924 to remove undesired signals caused by the upconversion of the signals and noise in the receive frequency band. A power amplifier (PA) 928 amplifies the upconverted signals 924 from the filter 926 to obtain a desired output power level and provide a transmit RF signal. The transmit RF signal is routed through a multiplexer or switch 930 and transmitted via an antenna 932 (eg, where the multiplexer may be a duplexer or any other such multiplexing circuit).

[0099] In the receive path, antenna 932 receives the signal transmitted by the base station and provides a received RF signal, which is routed through a multiplexer or switch 930 and provided to a low noise amplifier (LNA) 934. Multiplexer or switch 930 is designed to operate with a specific receive (RX) and TX multiplexer frequency separation so that the RX signal is isolated from the TX signal. The received RF signal is amplified by LNA 934 and filtered by filter 936 to obtain the desired RF input signal. Down-conversion mixers 938 (1), 938 (2) mix the output of filter 936 with the I and Q RX LO signals (i.e., LO_I and LO_Q) from RX LO signal generator 940 to generate I and Q baseband signals. The I and Q baseband signals are amplified by AMPs 942(1), 942(2) and further filtered by low pass filters 944(1), 944(2) to obtain I and Q analog input signals, which are provided to the data processor 906. In this example, the data processor 906 includes analog-to-digital converters (ADCs) 946(1), 946(2) to convert the analog input signals into digital signals to be further processed by the data processor 906.

[0100] exist Fig. 9In the wireless communication device 900 of FIG. 1 , the TX LO signal generator 922 generates I and Q TX LO signals for up-conversion, and the RX LO signal generator 940 generates I and Q RX LO signals for down-conversion. Each LO signal is a periodic signal with a specific base frequency. The TX phase-locked loop (PLL) circuit 948 receives timing information from the data processor 906 and generates a control signal for adjusting the frequency and / or phase of the TX LO signal from the TX LO signal generator 922. Similarly, the RX PLL circuit 950 receives timing information from the data processor 906 and generates a control signal for adjusting the frequency and / or phase of the RX LO signal from the RX LO signal generator 940.

[0101] The wireless communication devices 900 may each include a stacked AW filter package 903. The stacked AW filter package 903 includes a first AW filter circuit disposed on a first substrate, a second AW filter circuit disposed on a second substrate, and a metal layer for isolating the first AW filter circuit from the second AW filter circuit to reduce crosstalk, such as Figure 2A To Figure 2C, Figure 3 4, and can be provided in or integrated into any processor-based device according to any of the aspects disclosed herein. As shown, the multiplexer or switch 930 can include a stacked AW assembly as described herein. In some specific implementations, the filters 926 and 936 can also include a stacked AW assembly as described herein. In some such specific implementations, the filters 926 and 936 can be positioned between the PA or LNA and the Fig. 9 Examples, not limiting, include: a set-top box, an entertainment unit, a navigation device, a communication device, a fixed location data unit, a mobile location data unit, a global positioning system (GPS) device, a mobile phone, a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a tablet, a phablet, a server, a computer, a portable computer, a mobile computing device, a wearable computing device (e.g., a smart watch, a health or fitness tracker, glasses, etc.), a desktop computer, a personal digital assistant (PDA), a monitor, a computer monitor, a television, a tuner, a radio, a satellite broadcast, a music player, a digital music player, a portable music player, a digital video player, a video player, a digital video disc (DVD) player, a portable digital video player, an automobile, a vehicle assembly, an avionics system, a drone, and a multirotor aircraft.

[0102] Fig.10 According to the examples described herein, the disclosed stacked AW filter (e.g., Figure 4AStacked AW filter package 400, Figure 5 The stacked AW filter package 500 has Figure 6 Schematic diagram of filter 1000 of the embodiment of the present invention (such as the stacked AW filter with improved performance illustrated by transmit (TX) leakage data 620 in the chart of FIG. 1000). Specifically, filter 1000 includes a ladder arrangement of acoustic SAW resonators Rs, Rp (where Rs is a series resonator and Rp is a parallel resonator). The disclosed stacked AW filter can couple SAW resonators (e.g., 450, 452, 454, etc.) to implement filter 1000, while including the described elements for reducing the excitation of body waves in the stacked AW filter used to implement filter 1000.

[0103] The ladder structure of the filter 1000 includes a plurality of basic sections BS. Each basic section BS includes at least one series resonator Rs and at least one parallel resonator Rp. The basic sections BS can be connected in series with the number of basic sections BS required to achieve the desired selectivity. The series resonators Rs belonging to adjacent basic sections BS can be combined into a common series resonator Rs, and if the parallel resonators Rp are directly adjacent and belong to different basic sections BS, these parallel resonators can also be combined. One basic section BS provides a basic filter. More basic sections BS are added to provide sufficient selectivity.

[0104] Fig.11 is a diagram of an environment 1100 including an electronic device 1102 that includes a wireless transceiver 1196, such as Fig. 9 In addition, as shown, the wireless transceiver 1196 may include a filter 1197. The filter 1197 may be implemented as a stacked AW filter as described herein (e.g., Figure 4A Stacked AW filter package 400, Figure 5 The stacked AW filter package 500 has Figure 6 119). Additionally, while the electronic device 1102 is illustrated as having a wireless transceiver 1196 including a filter 1197, the base station 1104 may include similar wireless transceiver circuitry implemented with stacked AW filters as described herein.

[0105] In some aspects, the electronic device 1102 includes a display screen 1199, which can be used to display information associated with data sent via a wireless link 1106 and processed using components of the electronic device 1102 described below. Other aspects of the electronic device using a low phase delay filter for multi-band communication according to various aspects described herein may not be configured with a display screen. In the environment 1100, the electronic device 1102 communicates with the base station 1104 via a wireless link 1106. As shown, the electronic device 1102 is depicted as a smart phone. However, the electronic device 1102 can be implemented as any suitable computing electronic device or other electronic device, such as a cellular base station, a broadband router, an access point, a cellular or mobile phone, a gaming device, a navigation device, a media device, a laptop computer, a desktop computer, a tablet computer, a server computer, a network attached storage (NAS) device, a smart appliance, a car including a vehicle-based communication system, an Internet of Things (IoT) device, a sensor or security device, an asset tracker, etc.

[0106] Base station 1104 communicates with electronic device 1102 via wireless link 1106, which may be implemented as any suitable type of wireless link. Although depicted as a base station tower of a cellular radio network, base station 1104 may represent or be implemented as another device, such as a satellite, a terrestrial broadcast tower, an access point, a peer device, a mesh network node, a fiber optic line, another electronic device substantially as described above, etc. Thus, electronic device 1102 may communicate with base station 1104 or another device via a wired connection, a wireless connection, or a combination thereof. Wireless link 1106 may include a downlink of data or control information communicated from base station 1104 to electronic device 1102, and an uplink of other data or control information communicated from electronic device 1102 to base station 1104. Wireless link 1106 may use any suitable communication protocol or standard (such as, Third Generation Partnership Project Long Term Evolution (3GPP LTE, 3GPP NR 5G), IEEE 802.11, IEEE 802.16, Bluetooth TM etc.) to achieve this.

[0107] The electronic device 1102 includes a processor 1180 and a memory 1182. The memory 1182 may be part of or form part of a computer-readable storage medium. The processor 1180 may include any type of processor configured to execute processor-executable instructions (e.g., code) stored by the memory 1182, such as an application processor or a multi-core processor. The memory 1182 may include any suitable type of data storage medium, such as a volatile memory (e.g., random access memory (RAM)), a non-volatile memory (e.g., flash memory), an optical medium, a magnetic medium (e.g., a disk or tape), etc. In the context of the present disclosure, the memory 1182 is implemented to store instructions 1184, data 1186, and other information of the electronic device 1102, and therefore when configured as a computer-readable storage medium or a part thereof, the memory 1182 does not include a transient propagation signal or carrier wave.

[0108] The electronic device 1102 may also include an input / output (I / O) port 1190. The I / O port 1190 enables data exchange or interaction with other devices, networks, or users or components of the device.

[0109] The electronic device 1102 may also include a signal processor (SP) 1192 , such as, for example, a digital signal processor (DSP). The signal processor 1192 may function similarly to a processor and may be capable of executing instructions and / or processing information in conjunction with the memory 1182 .

[0110] For communication purposes, the electronic device 1102 also includes a modem 1194, a wireless transceiver 1196, and an antenna (not shown). The wireless transceiver 1196 uses radio frequency (RF) wireless signals to provide connectivity to corresponding networks and other electronic devices connected to these corresponding networks, and may include Fig. 9 The wireless transceiver 1196 may facilitate communications over any suitable type of wireless network, such as a wireless local area network (LAN) (WLAN), a peer-to-peer (P2P) network, a mesh network, a cellular network, a wireless wide area network (WWAN), a navigation network (e.g., the Global Positioning System (GPS) or another Global Navigation Satellite System (GNSS) for North America), and / or a wireless personal area network (WPAN).

[0111] The various operations of the above methods may be performed by any suitable component capable of performing the corresponding functions. The component may include various hardware and / or software components and / or modules, including but not limited to circuits, application specific integrated circuits (ASICs) or processors.

[0112] In an aspect, the elements described herein, or any part of the elements, or any combination of the elements, can be implemented as a "processing system" including one or more processors. Aspects of the processor include a microprocessor, a microcontroller, a graphics processing unit (GPU), a central processing unit (CPU), an application processor, a digital signal processor (DSP), a reduced instruction set computing (RISC) processor, a system on a chip (SoC), a baseband processor, a field programmable gate array (FPGA), a programmable logic device (PLD), a state machine, a gated logic unit, a discrete hardware circuit, and other suitable hardware configured to perform various functionalities described throughout the present disclosure. One or more processors in the processing system can execute software. Whether it is referred to as software, firmware, middleware, microcode, hardware description language or other names, software should be widely interpreted as meaning instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, processes, functions, etc.

[0113] Therefore, in one or more aspects of the embodiment, function or circuit block can be implemented by hardware, software or any combination thereof. If implemented by software, the function can be stored or encoded on a computer-readable medium as one or more instructions or codes. Computer-readable media include computer storage media. Storage media can be any available medium that can be accessed by a computer. In an aspect and not a limiting manner, such computer-readable media may include a random access memory (RAM), a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), an optical disk storage device, a magnetic disk storage device, other magnetic storage devices, a combination of computer-readable media of the aforementioned types, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer. In some aspects, the components described in circuits can be implemented by hardware, software or any combination thereof.

[0114] Illustrative aspects of the present disclosure include:

[0115] Aspect 1. A stacked acoustic wave (AW) filter circuit, comprising: a first substrate, the first substrate comprising a first surface and a second surface, wherein the second surface is opposite to the first surface; a first AW resonator circuit, the first AW resonator circuit being positioned on the first surface of the first substrate; a plurality of elements, the plurality of elements comprising a first element, wherein the plurality of elements are positioned on the second surface of the first substrate, and wherein the first element is aligned with the first AW resonator circuit; and a second substrate, the second substrate comprising a first surface and a second surface, wherein the plurality of elements are positioned on the first surface of the second substrate, and wherein the plurality of elements create a cavity between the first substrate and the second substrate.

[0116] Aspect 2. The stacked AW filter circuit according to aspect 1 further comprises: a second AW resonator circuit, the second AW resonator circuit being positioned on the first surface of the second substrate in the cavity between the first substrate and the second substrate.

[0117] Aspect 3. A stacked AW filter circuit according to any one of Aspects 1 to 2, wherein the second AW resonator circuit is positioned between the first element and the second element so that the first element and the second element provide mechanical support for the cavity to prevent the second AW resonator circuit from contacting the first substrate.

[0118] Aspect 4. The stacked AW filter circuit according to any one of Aspects 1 to 3 further includes: a first plurality of AW resonator circuits arranged on the first surface of the first substrate, the first plurality of AW resonator circuits including the first AW resonator circuit; and a second plurality of AW resonator circuits arranged on the first surface of the second substrate, the second plurality of AW resonator circuits including the second AW resonator circuit; wherein the first plurality of AW resonator circuits and the second plurality of AW resonator circuits are each electrically coupled to a corresponding signal path as part of a radio frequency (RF) filter.

[0119] Aspect 5. The stacked AW filter circuit according to any one of Aspects 1 to 4 further includes: a molding material covering at least a portion of the second surface of the second substrate, wherein the molding material is aligned with the position of the second AW resonator circuit to attenuate reflection of body waves entering the second substrate from the second AW resonator circuit.

[0120] Aspect 6. The stacked AW filter circuit according to any one of Aspects 1 to 5 further includes: a cover substrate having a first surface and a second surface; and a second plurality of elements, the second plurality of elements being positioned on the first surface of the first substrate and the second surface of the cover substrate to produce a second cavity, wherein the second cavity is positioned between the first substrate and the cover substrate.

[0121] Aspect 7. The stacked AW filter circuit according to any one of Aspects 1 to 6 further includes: at least one conductive interconnect, which is mounted on the first surface of the cover substrate and electrically coupled to the first AW resonator circuit as part of a radio frequency (RF) filter.

[0122] Aspect 8. The stacked AW filter circuit according to any one of aspects 1 to 7, wherein the plurality of elements comprises polymer elements, and wherein the second plurality of elements comprises polymer elements.

[0123] Aspect 9. The stacked AW filter circuit according to any one of aspects 1 to 8, wherein the plurality of elements comprises uniform or structured metal elements, and wherein the second plurality of elements comprises uniform or structured metal elements.

[0124] Aspect 10. The stacked AW filter circuit according to any one of Aspects 1 to 9 further includes: a uniform polymer layer covering at least a portion of the second surface of the first substrate within a reflected body wave path from the first AW resonator circuit through the first substrate.

[0125] Aspect 11. The stacked AW filter circuit according to any one of aspects 1 to 10, wherein the plurality of elements provide structural support to maintain the physical position of the first substrate and the second substrate within the stacked AW filter circuit.

[0126] Aspect 12. The stacked AW filter circuit according to any one of Aspects 1 to 11 further includes a polymer frame arranged on the second surface of the first substrate and on the first surface of the second substrate, wherein the polymer frame is positioned at an edge portion of the first surface of the second substrate and an edge portion of the second surface of the first substrate to encapsulate the cavity.

[0127] Aspect 13. The stacked AW filter circuit according to any one of aspects 1 to 12, wherein the first element extends from the polymer frame at an edge portion of the first surface of the second substrate into the cavity.

[0128] Aspect 14. A stacked AW filter circuit according to any one of Aspects 1 to 13, wherein the first element is positioned within the cavity without being connected to the polymer frame at the edge portion of the first surface of the second substrate or the edge portion of the second surface of the first substrate.

[0129] Aspect 15. The stacked AW filter circuit according to any one of aspects 1 to 14, wherein the first AW resonator circuit comprises a plurality of surface acoustic wave (SAW) resonators.

[0130] Aspect 16. A stacked AW filter circuit according to any one of Aspects 1 to 15, wherein the first element is aligned with the first AW resonator circuit so that one or more body waves enter the first substrate from the first AW resonator circuit at a position between the first AW resonator circuit and the first element.

[0131] Aspect 17. A stacked AW filter circuit according to any one of Aspects 1 to 16, wherein the first element is a polymer structural support wall for the first substrate, and wherein the first element is positioned so that one or more body waves enter the first substrate from the first AW resonator and are reflected at a position where the second surface of the first substrate contacts the first element.

[0132] Aspect 18. A stacked AW filter circuit according to any one of Aspects 1 to 17, wherein the first AW resonator includes an interdigital transducer (IDT) electrode structure positioned on a piezoelectric surface in a first plane parallel to the first surface of the first substrate; wherein the first element contacts the second surface of the first substrate in an acoustic reflection attenuation region of a second plane parallel to the first plane.

[0133] Aspect 19. A stacked AW filter circuit according to any one of Aspects 1 to 18, wherein the first element is positioned so that a projection of an area of ​​the IDT electrode structure onto the second plane in a direction perpendicular to the first plane causes the projection at the second plane to overlap with the acoustic reflection attenuation area in the second plane.

[0134] Aspect 20. A stacked AW filter circuit according to any one of Aspects 1 to 19, wherein the stacked AW filter circuit is integrated into a device selected from the group consisting of: a set-top box; an entertainment unit; a navigation device; a communication device; a fixed location data unit; a mobile location data unit; a global positioning system (GPS) device; a mobile phone; a cellular phone; a smart phone; a session initiation protocol (SIP) phone; a tablet computer; a tablet phone; a server; a computer; a portable computer; a mobile computing device; a wearable computing device; a desktop computer; a personal digital assistant (PDA); a monitor; a computer monitor; a television; a tuner; a radio; a satellite radio; a music player; a digital music player; a portable music player; a digital video player; a video player; a digital video disc (DVD) player; a portable digital video player; an automobile; a vehicle component; an avionics system; a drone; and a multirotor aircraft.

[0135] Aspect 21. The stacked AW filter circuit according to any one of aspects 1 to 20, wherein the stacked AW filter circuit is integrated into a radio frequency (RF) front-end circuit of a transceiver.

[0136] Aspect 22. The stacked AW filter circuit according to any one of aspects 1 to 21, wherein the front-end circuit of the transceiver comprises a multiplexer coupled to an antenna, wherein the multiplexer comprises the stacked AW filter circuit.

[0137] Aspect 23. A method for filtering a radio frequency (RF) signal, the method comprising: providing a signal at an interconnect of a stacked acoustic wave (AW) filter package, wherein the interconnect is positioned on a cover substrate; exciting an acoustic wave at a first AW resonator circuit on a first substrate positioned at a stacking layer separated from the cover substrate, wherein the first AW resonator circuit is electrically coupled to the interconnect, and wherein the first AW resonator circuit is positioned within a first cavity supported by an element between the cover substrate and the first substrate; and attenuating a body wave from the first AW resonator circuit in the first substrate using a reflection suppression element positioned at a side of the first substrate opposite to the first AW resonator circuit, wherein the reflection suppression element is also positioned to support a second cavity between the first substrate and a second substrate, and wherein the second substrate is at an additional stacking layer separated from both the cover substrate and the first substrate.

[0138] Aspect 24. The method according to aspect 23, wherein the reflection suppression element comprises a metal element in a uniform metal layer.

[0139] Aspect 25. A wireless communication device, comprising: a stacked acoustic wave (AW) filter package, the stacked acoustic wave (AW) filter package comprising: a first substrate, the first substrate having a first plurality of AW resonator circuits positioned on a top side; a second substrate, the second substrate having a second plurality of AW resonator circuits positioned on a top side; a frame, the frame positioned between the first substrate and the second substrate to create a cavity between the bottom side of the first substrate and the top side of the second substrate; and one or more acoustic reflection suppression structural walls, the one or more acoustic reflection suppression structural walls supporting the cavity between the bottom side of the first substrate and the top side of the second substrate, the one or more acoustic reflection suppression structural walls positioned at selected positions on the back side of the first substrate to attenuate selected acoustic body wave paths from the first plurality of AW resonator circuits that interfere in the signal path of the stacked AW filter package.

[0140] Aspect 26. The wireless communication device according to Aspect 25 further includes: one or more non-structural elements, wherein the one or more non-structural elements are positioned at a portion of the back side of the first substrate to attenuate a second selected acoustic bulk wave path from the first plurality of AW resonator circuits that interferes in the signal path of the stacked AW filter package.

[0141] Aspect 27. A wireless communication device according to any one of aspects 25 to 26, wherein the one or more acoustic reflection suppression structural walls and the one or more non-structural elements comprise a polymer material in a shared manufacturing layer.

[0142] Aspect 28. The wireless communication device according to any one of Aspects 25 to 27 further includes: one or more antennas; and a processing circuit, wherein the one or more antennas and the processing circuit are communicatively coupled via the signal path of the stacked AW filter package, and wherein the first plurality of AW resonator circuits and the second plurality of AW resonator circuits are electrically coupled to form one or more radio frequency (RF) filters for signals traveling between the one or more antennas and the processing circuit.

[0143] Aspect 29. A wireless communication device, comprising: a first substrate, the first substrate comprising a first surface and a second surface, wherein the second surface is opposite to the first surface; a first electroacoustic component, the first electroacoustic component being used to filter a radio frequency signal, wherein the first electroacoustic component is positioned on the first surface of the first substrate; and a component for suppressing acoustic body waves, the component for suppressing acoustic body waves being at the second surface of the first substrate.

[0144] Aspect 30. The wireless communication device according to aspect 29, wherein the means for suppressing bulk acoustic waves further comprises means for providing structural support for the first substrate.

[0145] Aspect 31. A storage medium comprising instructions, which when executed by a processing circuit of a device causes the device to perform operations according to any of the above aspects.

[0146] Aspect 32. A method for filtering a signal according to any of the above aspects.

[0147] Aspect 33. An apparatus comprising means for filtering a signal according to any of the above aspects.

[0148] The phrase "coupled to" and the term "coupled" refer to any component being physically connected directly or indirectly to another component and / or any component being in communication directly or indirectly with another component (e.g., connected to another component via a wired or wireless connection and / or other suitable communication interface). Generally, where there are operations illustrated in the figures, those operations may have corresponding corresponding means-plus-function components with similar numbering.

[0149] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include computing, calculating, processing, deriving, investigating, searching (e.g., searching in a table, a database, or another data structure), ascertaining, etc. In addition, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), etc. In addition, "determining" may include resolving, selecting, choosing, establishing, etc.

[0150] It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims.

Claims

1. A stacked acoustic wave (AW) filter circuit comprising: a first substrate, the first substrate comprising a first surface and a second surface, wherein the second surface is opposite to the first surface; a first AW resonator circuit positioned on the first surface of the first substrate; a plurality of elements, the plurality of elements including a first element, wherein the plurality of elements are positioned on the second surface of the first substrate, and wherein the first element is aligned with the first AW resonator circuit; and A second substrate includes a first surface and a second surface, wherein the plurality of elements are positioned on the first surface of the second substrate, and wherein the plurality of elements create a cavity between the first substrate and the second substrate.

2. The stacked AW filter circuit according to claim 1, further comprising: A second AW resonator circuit is positioned on the first surface of the second substrate in the cavity between the first substrate and the second substrate.

3. The stacked AW filter circuit of claim 2 , wherein the second AW resonator circuit is positioned between the first element and the second element such that the first element and the second element provide mechanical support for the cavity to prevent the second AW resonator circuit from contacting the first substrate.

4. The stacked AW filter circuit according to claim 2, further comprising: a first plurality of AW resonator circuits disposed on the first surface of the first substrate, the first plurality of AW resonator circuits including the first AW resonator circuit; as well as a second plurality of AW resonator circuits disposed on the first surface of the second substrate, the second plurality of AW resonator circuits including the second AW resonator circuit; Wherein the first plurality of AW resonator circuits and the second plurality of AW resonator circuits are each electrically coupled to a corresponding signal path as part of a radio frequency (RF) filter.

5. The stacked AW filter circuit according to claim 2, further comprising: An attenuating material covers at least a portion of the second surface of the second substrate, wherein the attenuating material is aligned with a location of the second AW resonator circuit to attenuate reflections of bulk waves entering the second substrate from the second AW resonator circuit.

6. The stacked AW filter circuit according to claim 5, further comprising: a cover substrate having a first surface and a second surface; and A second plurality of elements are positioned on the first surface of the first substrate and the second surface of the cover substrate to create a second cavity, wherein the second cavity is positioned between the first substrate and the cover substrate.

7. The stacked AW filter circuit according to claim 6, further comprising: At least one conductive interconnect is mounted on the first surface of the cover substrate and is electrically coupled to the first AW resonator circuit as part of a radio frequency (RF) filter.

8. The stacked AW filter circuit of claim 6, wherein the plurality of elements comprise polymer elements, and wherein the second plurality of elements comprise polymer elements.

9. The stacked AW filter circuit of claim 6, wherein the plurality of elements comprise uniform or structured metal elements, and wherein the second plurality of elements comprise uniform or structured metal elements.

10. The stacked AW filter circuit according to claim 1, further comprising: A uniform or structured polymer layer covers at least a portion of the second surface of the first substrate within a reflected bulk wave path from the first AW resonator circuit through the first substrate.

11. The stacked AW filter circuit of claim 1 , wherein the plurality of elements provide structural support to maintain the physical position of the first substrate and the second substrate within the stacked AW filter circuit.

12. The stacked AW filter circuit according to claim 1 further includes a polymer frame arranged on the second surface of the first substrate and on the first surface of the second substrate, wherein the polymer frame is positioned at an edge portion of the first surface of the second substrate and an edge portion of the second surface of the first substrate to encapsulate the cavity. 13 . The stacked AW filter circuit of claim 12 , wherein the first element extends from the polymer frame at an edge portion of the first surface of the second substrate into the cavity.

14. The stacked AW filter circuit of claim 12, wherein the first element is positioned within the cavity without being connected to the polymer frame at the edge portion of the first surface of the second substrate or the edge portion of the second surface of the first substrate.

15. The stacked AW filter circuit of claim 1, wherein the first AW resonator circuit comprises a plurality of surface acoustic wave (SAW) resonators.

16. The stacked AW filter circuit of claim 1, wherein the first element is aligned with the first AW resonator circuit such that one or more bulk waves enter the first substrate from the first AW resonator circuit at a location between the first AW resonator circuit and the first element.

17. The stacked AW filter circuit of claim 1 , wherein the first element is a polymer structural support wall for the first substrate, and wherein the first element is positioned such that one or more bulk waves enter the first substrate from the first AW resonator and are reflected at a location where the second surface of the first substrate contacts the first element.

18. The stacked AW filter circuit of claim 1 , wherein the first AW resonator comprises an interdigital transducer (IDT) electrode structure positioned on a piezoelectric surface in a first plane parallel to the first surface of the first substrate; The first element contacts the second surface of the first substrate in an acoustic reflection attenuation region of a second plane parallel to the first plane.

19. The stacked AW filter circuit according to claim 18, wherein the first element is positioned so that a projection of an area of ​​the IDT electrode structure onto the second plane in a direction perpendicular to the first plane causes the projection at the second plane to overlap with the acoustic reflection attenuation area in the second plane.

20. The stacked AW filter circuit of claim 1, wherein the stacked AW filter circuit is integrated into a device selected from the group consisting of: a set-top box; an entertainment unit; a navigation device; a communication device; a fixed location data unit; a mobile location data unit; a global positioning system (GPS) device; a mobile phone; a cellular phone; a smart phone; Session Initiation Protocol (SIP) phones; tablet computers; phablets; servers; computers; portable computers; mobile computing devices; wearable computing devices; desktop computers; personal digital assistants (PDAs); monitors; computer monitors; televisions; tuners; radios; satellite radios; music players; digital music players; portable music players; digital video players; video players; digital video disc (DVD) players; portable digital video players; automobiles; vehicle components; avionics systems; drones; and multirotors.

21. The stacked AW filter circuit of claim 1, wherein the stacked AW filter circuit is integrated into a radio frequency (RF) front-end circuit of a transceiver.

22. The stacked AW filter circuit of claim 21, wherein the front-end circuit of the transceiver comprises a multiplexer coupled to an antenna, wherein the multiplexer comprises the stacked AW filter circuit.

23. A method for filtering a radio frequency (RF) signal, the method comprising: providing a signal at an interconnect of a stacked acoustic wave (AW) filter package, wherein the interconnect is positioned on a cover substrate; exciting an acoustic wave at a first AW resonator circuit on a first substrate positioned at a stacked layer separate from the cover substrate, wherein the first AW resonator circuit is electrically coupled to the interconnect, and wherein the first AW resonator circuit is positioned within a first cavity supported by an element between the cover substrate and the first substrate; as well as Bulk waves in the first substrate from the first AW resonator circuit are attenuated using a reflection suppression element positioned at a side of the first substrate opposite to the first AW resonator circuit, wherein the reflection suppression element is also positioned to support a second cavity between the first and second substrates, and wherein the second substrate is at an additional stacked layer separated from both the cover substrate and the first substrate.

24. The method of claim 23, wherein the reflection-inhibiting element comprises a metal element in a uniform or structured metal layer.

25. A wireless communication device, comprising: A stacked acoustic wave (AW) filter package, the stacked acoustic wave (AW) filter package comprising: a first substrate having a first plurality of AW resonator circuits positioned on a top side; a second substrate having a second plurality of AW resonator circuits positioned on a top side; a frame positioned between the first substrate and the second substrate to create a cavity between a bottom side of the first substrate and the top side of the second substrate; and One or more acoustic reflection suppression structural walls, the one or more acoustic reflection suppression structural walls supporting the cavity between the bottom side of the first substrate and the top side of the second substrate, the one or more acoustic reflection suppression structural walls positioned at selected positions on the back side of the first substrate to attenuate selected acoustic body wave paths from the first plurality of AW resonator circuits that interfere in the signal path of the stacked AW filter package.

26. The wireless communication device of claim 25, further comprising: One or more non-structural elements are positioned at a portion of the back side of the first substrate to attenuate a second selected BAW path from the first plurality of AW resonator circuits that interferes in the signal path of the stacked AW filter package.

27. The wireless communication device of claim 26, wherein the one or more acoustic reflection suppressing structural walls and the one or more non-structural elements comprise a polymer material in a shared manufacturing layer.

28. The wireless communication device of claim 27, further comprising: one or more antennas; and processing circuitry, wherein the one or more antennas and the processing circuitry are communicatively coupled via the signal path of the stacked AW filter package, and wherein the first plurality of AW resonator circuits and the second plurality of AW resonator circuits are electrically coupled to form one or more radio frequency (RF) filters for signals traveling between the one or more antennas and the processing circuitry.

29. A wireless communication device, comprising: a first substrate, the first substrate comprising a first surface and a second surface, wherein the second surface is opposite to the first surface; an electroacoustic component for filtering radio frequency signals, wherein the electroacoustic component for filtering the radio frequency signals is positioned on the first surface of the first substrate; and A member for suppressing bulk acoustic waves, the member for suppressing bulk acoustic waves is at the second surface of the first substrate.

30. The wireless communication device of claim 29, wherein the means for suppressing bulk acoustic waves further comprises means for providing structural support for the first substrate.

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