Systems and methods for acoustically isolated resonators

Abstract

The systems and methods disclosed herein include devices having a bulk acoustic wave resonator and one or more grooves configured to impede the flow of acoustic energy to the bulk acoustic wave resonator.

Description

[Technical Field]

[0001] TECHNICAL FIELD This disclosure relates to acoustically isolated resonators, and more particularly to systems and methods for acoustically isolated bulk wave resonator gyroscopes. [Background technology]

[0002] Coupling of acoustic energy into a resonator can increase the noise of the resonator. Fluctuations in the coupled acoustic energy can cause fluctuations in the output of the resonator, which can degrade the performance of the resonator. These and other deficiencies exist. Summary of the Invention

[0003] An embodiment of the present disclosure provides a device including a substrate. The device may include a bulk acoustic wave resonator disposed on at least a first surface of the substrate. The substrate may include one or more grooves configured to impede the flow of acoustic energy to the bulk acoustic wave resonator.

[0004] An embodiment of the present disclosure provides a device including a plurality of device components. A first device component selected from the plurality of device components may include a plurality of grooves and / or cavities. A second device component selected from the plurality of device components may be sensitive to acoustic energy. The plurality of grooves are configured to impede the flow of acoustic energy to the second device component.

[0005] An embodiment of the present disclosure provides a device including a substrate. The device may include a resonator coupled to a first surface of the substrate. The resonator may include a bulk acoustic wave resonator gyroscope capacitively transduced via one or more electrodes. The device may include a cap structure. The cap structure may include one or more grooves configured to impede the flow of acoustic energy to the resonator. The cap structure may include one or more cavities configured to impede the flow of acoustic energy to the resonator. [Brief explanation of the drawings]

[0006] [Figure 1A] FIG. 1 is a cross-sectional view of a device according to one exemplary embodiment. [Figure 1B] 10 is a cross-sectional view of a device according to another exemplary embodiment. [Figure 2] 10 is a cross-sectional view of a device according to another exemplary embodiment. [Figure 3A] 10 is a cross-sectional view of a device according to another exemplary embodiment. [Figure 3B] 10 is a cross-sectional view of a device according to another exemplary embodiment. [Figure 4] 10 is a cross-sectional view of a device according to another exemplary embodiment. [Figure 5A] 1A-1C are plan views of various patterns according to one exemplary embodiment. [Figure 5B] 1A-1C are plan views of various patterns according to one exemplary embodiment. [Figure 5C] 1A-1C are plan views of various patterns according to one exemplary embodiment. [Figure 5D] 1A-1C are plan views of various patterns according to one exemplary embodiment. [Figure 5E] 1A-1C are plan views of various patterns according to an exemplary embodiment. [Figure 5F] 1A-1C are plan views of various patterns according to an exemplary embodiment. [Figure 5G] 1A-1C are plan views of various patterns according to one exemplary embodiment. [Figure 5H] 1A-1C are plan views of various patterns according to one exemplary embodiment. [Figure 6] 10 is a cross-sectional view of a device according to another exemplary embodiment. [Figure 7] 10 is a cross-sectional view of a device according to another exemplary embodiment. [Figure 8] 1 is a graph of figure of merit and groove dimensions according to an exemplary embodiment. [Figure 9A] 1 is a die attach pattern according to an exemplary embodiment. [Figure 9B] 1 is a die attach pattern according to an exemplary embodiment. [Figure 9C] 1 is a die attach pattern according to an exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] The following description of the embodiments provides non-limiting representative examples that specifically describe the features and teachings of various aspects of the present invention by reference to numerals. It should be recognized from the description of the embodiments that the described embodiments can be implemented separately or in combination with other embodiments. Those skilled in the art who review the description of the embodiments should be able to know and understand the described various aspects of the present invention. The description of the embodiments should facilitate understanding of the present invention to the extent that other implementations that are not expressly exhaustive but are within the knowledge of those skilled in the art who read the description of the embodiments will be understood to be consistent with the application of the present invention.

[0008] When acoustic energy is coupled into a resonator, its performance can be degraded. For example, acoustic energy can increase the noise of the resonator or affect the zero-rate offset of a resonator-based gyroscope. Furthermore, temperature-dependent acoustic energy coupling into the resonator can result in temperature-dependent effects such as higher-order zero-rate offset versus temperature behavior. Besides temperature, unwanted acoustic energy coupling can vary with other operating conditions, such as stress or external fields, which can degrade device performance. The source of unwanted acoustic energy can be internal or external to the device. Acoustic energy can be generated due to electrostatic transduction in the resonator and electrodes. Thus, in some examples, the resonator and electrodes can be a strong source of acoustic energy.

[0009] As used herein, unwanted acoustic energy may refer to acoustic energy that is coupled to anchor 106 even when generated within resonator 101, which may or may not be external to resonator 101. As such, unwanted acoustic energy is not limited to energy only external to resonator 101, as it may be generated from within resonator 101 and / or from the environment external to resonator 101, and as further described herein, grooves such as groove 901 are configured to impede the flow of unwanted acoustic energy upon bouncing, such as, but not limited to, one or more flow paths. In some examples, unwanted acoustic energy may couple to resonator 101 through structures other than anchor 106, such as, but not limited to, connector 1501 (shown in FIG. 7 , etc.). In some examples, there may be unwanted acoustic energy coupling to resonator 101 through a medium surrounding the resonator. By way of example, medium may refer to a gas, a liquid, and / or any combination thereof located around resonator 101. Without limitation, the medium may be external to resonator 101.

[0010] To alleviate these problems, the grooves and / or cavities of the systems and methods disclosed herein can be arranged to disrupt one or more flow channels, reducing unwanted acoustic energy between the drive and sense modes of a gyroscope, such as a bulk acoustic wave resonator gyroscope. Such arrangements also reduce zero-rate offset and higher-order zero-rate offset versus temperature behavior in the resonator gyroscope, resulting in improved device performance.

[0011] 1A shows a cross-sectional view of a device 100 according to one exemplary embodiment. Device 100 may include a resonator 101, a substrate 102, an electrode 103, a transducing gap 104, a cap structure 105, an anchor 106, a bond pad 107, a wire bond 108, and one or more grooves 901. While FIG. 1A shows a single instance of the components of device 100, it will be understood that any number of the components of device 100 may be included.

[0012] 1A , acoustic energy can be provided from several sources, including, for example, sources 110, 115, 120, and 125 external to device 100, source 130 due to movement of wirebond 108, source 135 due to movement of bond pad 107, source 140 due to movement of substrate 102, source 145 due to movement of cap structure 105, source 150 due to movement of resonator 101, source 155 due to movement of anchor 106, and source 160 due to movement of electrode 103. While arrows represent movement of sources 145, 150, 155, and 160, they do not necessarily represent the direction of movement, as the movement or vibration can occur in any direction, e.g., longitudinal, transverse, lateral, diagonal, serpentine, etc. As described further below, device 100 can be configured to isolate resonator 101 from unwanted acoustic energy to improve its performance.

[0013] The resonator 101 may include a bulk acoustic wave resonator gyroscope. The bulk acoustic wave resonator may be disposed on at least a first surface of a substrate 102. For example, the resonator 101 may be connected to the first surface of the substrate 102 via anchors 106. The resonator 101 may be capacitively transduced through one or more electrodes 103. In some examples, the one or more electrodes 103 may include one or more peripheral electrodes. In other examples, the one or more electrodes 103 may include one or more non-peripheral electrodes. In still other examples, the one or more electrodes 103 may include peripheral electrodes, non-peripheral electrodes, and / or any combination thereof. For example, FIG. 1B illustrates a device 100 further including a non-peripheral electrode 109. In some examples, the non-peripheral electrode 109 may include a planar electrode. Capacitive transduction may occur between the non-peripheral electrode 109 and the resonator 101 through a gap 111. While FIG. 1B illustrates a single instance of a component of the device 100, it will be understood that any number of components of the device 100 may be included. 1B may refer to the same components of device 100 as described above with respect to FIG. 1A. A transduction gap 104 may separate resonator 101 from one or more electrodes 103. The transduction gap 104 may be disposed above a substrate 102. For example, the transduction gap 104 may be disposed above a first surface of the substrate 102.

[0014] Wirebond 108 is the bond pad 107 The bond pad 107 may be disposed on the first surface of the cap structure 105. In some examples, the bond pad 107 may be disposed on both ends of the first surface of the cap structure 105.

[0015] The substrate 102 may include one or more grooves 901 configured to impede the flow of unwanted acoustic energy to the bulk acoustic wave resonator. For example, the one or more grooves 901 may be symmetrically disposed within the substrate 102. In other examples, the one or more grooves 901 may be asymmetrically disposed within the substrate 102. Also, one or more grooves 901 may have the same or different shape as the other grooves 901. Furthermore, one or more grooves 901 may have the same or different size as the other grooves 901. For example, at least one groove 901 may extend more than halfway through the substrate 102, such as, but not limited to, in a direction perpendicular to the substrate 102. The length of the groove 901 may exceed the width of the groove 901. In other examples, the length of the groove 901 may be the same as or shorter than the width of the groove 901.

[0016] The one or more grooves 901 may be configured to impede the flow of unwanted acoustic energy into the resonator 101. In some examples, the presence of the one or more grooves 901 may be configured to impede the flow of unwanted acoustic energy into the resonator 101 via the anchor 106, such as one or more of the channels 302, 303, 304, and / or 305. As shown in FIGS. 1A-1B , acoustic energy generated at one or more of the electrodes 103 or cap structure 105 may reach the resonator 101 through the respective direct channels 303, 305. Acoustic energy generated at one or more of the electrodes 103 or cap structure 105 may reach the resonator 101 through the respective channels 302, 304 after one or more reflections, such as reflections off a second surface, such as the bottom surface of the substrate 102. It is understood that the reflection is not limited to a single reflection or reflection off the second surface of the substrate 102, but may additionally or alternatively include any number of reflections and / or reflections off any number of surfaces of the substrate 102 to form a flow path for the acoustic energy to pass to the resonator 101.

[0017] The one or more grooves 901 may be formed by one or more processes including, but not limited to, dry etching, wet etching, dicing, laser ablation, milling, and / or any combination thereof, and any number of the walls of the grooves 901 may be straight, tapered, rounded, corrugated, undulating, and / or any combination thereof.

[0018] The resonator 101 may be configured to resonate in multiple modes, such as a first mode and a second mode. A first mode, e.g., a drive mode, may correspond to vibration along a first axis, and a second mode, e.g., a sense mode, may correspond to vibration along a second axis, and thus these modes are orthogonal to one another. It is generally desirable for the frequencies of the drive mode and the sense mode to match, as this may tend to improve the signal-to-noise ratio of the resonator 101. For example, an angular rate gyroscope may be configured to operate in a mode-matched condition, such that the drive mode is configured to have the same resonant frequency as the sense mode. In some examples, unwanted acoustic coupling between the drive mode and the sense mode may occur through the flow channel 301. In this manner, acoustic energy generated in the resonator 101 by excitation of the drive mode may pass through the flow channel 301 and couple back into the sense mode of the resonator 101. Such coupling effects are particularly detrimental in a mode-matched configuration, since both modes are nominally at approximately the same frequency, making unwanted acoustic energy more likely to couple.

[0019] The cap structure 105 may be configured to at least partially encompass the resonator 101. The transduction gap 104 may include a spacing or gap between the resonator 101 and one or more electrodes 103. In some examples, the device 100 may include two or more transduction gaps 104. For example, two transduction gaps 104 may be located diametrically opposite each other, each in a relative position relative to the resonator 101 and a different electrode 103. The resonator 101 and one or more electrodes 103 may be formed, for example, in a base portion of the device 100, and the base portion may be bonded to the cap structure 105. The cap structure 105 may be disposed above the substrate 102. For example, the cap structure 105 may be disposed above a first surface of the substrate 102.

[0020] FIG. 2 illustrates a cross-sectional view of a device 100 according to another exemplary embodiment. FIG. 2 may reference the same components of the device 100 described above with reference to FIGS. 1A-1B. For brevity, the description of the components of the device 100 described above with reference to FIGS. 1A-1B that apply to FIG. 2 is omitted. While FIG. 2 illustrates a single instance of a component of the device 100, it will be understood that any number of components of the device 100 may be included. The device 100 may include one or more mounting structures 401. For example, at least one of the mounting structures 401 may be disposed below a second surface, such as the bottom surface of the substrate 102. The one or more mounting structures 401 may include one or more selected from the group consisting of soft die attach, hard die attach, adhesive, stud bumps, interposers, and / or any combination thereof. In particular, soft materials, including but not limited to soft die, may be used to avoid stress buildup during temperature changes. For example, using a soft die attach material may minimize thermal and packaging stresses acting on the MEMS die. A softer die attach may be less reliable, so a trade-off between stress effects and reliability is considered when selecting the type of die attach. While issues with unwanted acoustic energy exist when not utilizing grooves in the resonator 101 (as described herein), factors to consider when selecting a soft die attach include low stress during packaging and operation at various temperatures. In some examples, the die attach thickness value may range from a few microns to hundreds of microns. For example, the die attach thickness value may be configured as 50 microns.

[0021] In some examples, one or more mounting structures 401 may be disposed on both ends of the substrate 102. For example, one or more mounting structures 401 may be disposed symmetrically on both ends of the substrate 102. One or more mounting structures 401 may include a width that is shorter than the edge of the substrate 102 to which it is coupled. In other examples, one or more mounting structures 401 may include a width that is longer than the edge of the substrate 102 to which it is coupled. In some examples, one or more mounting structures 401 may be disposed adjacent to or toward the outer edge of one or more grooves 901 rather than the inner edge.

[0022] The device 100 may include one or more lower support structures 402. In some examples, the device 100 may include a single lower support structure 402. For example, the lower support structure 402 may be disposed between one or more mounting structures 401. In some examples, the lower support structure may extend longer than the length of each of the substrate 102 and the cap structure 105. The one or more lower support structures 402 may include at least one selected from the group of an integrated circuit, a printed circuit board, a package, an interposer, and the like.

[0023] As further shown in FIG. 2 , the first dimension 1201 can be smaller than the second dimension 1202 in a direction parallel to the one or more lower support structures 402. For example, the first dimension 1201 can be defined by a first distance from a first end, such as the outer edge of the first groove 901, to a second end, such as the outer edge of the second groove 901. In some examples, the outer edge of the groove 901 can include the edge farthest from the resonator 101. The second dimension 1202 can be defined by a second distance from a third end, such as the inner edge of the first electrode 103, to a fourth end, such as the inner edge of the second electrode 103. In some examples, the inner end of the electrode 103 can include the end closer to the resonator 101. In some examples, the device 100 can include two or more transduction gaps 104, which can be diametrically opposed to each other and each can be located relative to the resonator 101 and a different electrode 103. In some examples, selecting first dimension 1201 to be smaller than second dimension 1202 may prevent the flow of unwanted acoustic energy through channels 302 , 303 , and 305 .

[0024] 3A-3B each show a cross-sectional view of device 200 according to one exemplary embodiment. 3A-3B may reference the same components as device 100 described above with respect to FIGS. 1 and 2. For brevity, descriptions of the components of device 100 described above with respect to FIGS. 1 and 2 that apply to FIG. 3 are omitted. 3A-3B show a single instance of a component of device 200, but it will be understood that any number of components of device 200 may be included.

[0025] 3A , device 200 may include multiple device components 801, 802, and 803. For example, device component 801 and device component 803 may be disposed on the same surface of device component 802. In some examples, device component 801 and device component 803 may be disposed on opposite ends of a first surface of device component 802.

[0026] At least one of the device components selected from device components 801, 802, and 803, such as device component 802, may include a plurality of grooves 901, 902, 903, and 904. At least one of the device components, such as device component 801, may be sensitive to unwanted acoustic energy. The plurality of grooves 901, 902, 903, and 904 may be configured to impede the flow of unwanted acoustic energy to device component 801. Device component 801 may be separated from device component 803 by at least one groove, such as groove 902. In some examples, groove 901 may be a different size and / or shape than grooves 902, 903, and 904. As previously mentioned, unwanted acoustic energy may come from any of several sources external and / or internal to device 200.

[0027] The plurality of grooves 901, 902, 903, and 904 may be formed by one or more processes, including, but not limited to, dry etching, wet etching, dicing, laser ablation, milling, and / or any combination thereof. Also, the walls of any number of the grooves 901, 902, 903, and 904 may be straight, tapered, rounded, wavy, undulating, and / or any combination thereof.

[0028] As shown in FIG. 3B , device 200 may include multiple device components 801, 802, and 803, similar to that shown in FIG. 3A . Furthermore, at least one of device components 801 may include a bulk acoustic wave resonator 905 capacitively transduced by one or more electrodes. In this manner, device 200 may include bulk acoustic wave resonator 905 capacitively transduced by one or more electrodes, such as one or more surrounding electrodes. Furthermore, device 200 may include a cavity 904. For example, device component 802 may be configured to include a cavity 904 disposed below bulk acoustic wave resonator 905. Cavity 904 may be configured to impede the flow of acoustic energy to bulk acoustic wave resonator 905. Cavity 904 may be adjacent to at least one of the grooves, such as groove 902. Cavity 904 may be of any size and / or shape. Indeed, the plurality of grooves 901 , 902 , 903 , and 904 and the one or more cavities 904 may be configured to mitigate the flow of unwanted acoustic energy into the bulk acoustic wave resonator 905 .

[0029] FIG. 4 illustrates a cross-sectional view of device 200 according to one exemplary embodiment. FIG. 4 may reference the same components as device 100 described above with respect to FIGS. 1 and 2 and device 200 described above with respect to FIGS. 3A-3B. For brevity, the description of the components of device 100 described above with respect to FIGS. 1 and 2 and the components of device 200 described above with respect to FIGS. 3A-3B that apply to FIG. 4 will be omitted. While FIG. 4 illustrates a single instance of a component of device 200, it will be understood that any number of the components of device 200 may be included.

[0030] Device 200 may include multiple device components 801, 802, and 803, one or more mounting structures 401, and one or more lower support structures 402. For example, device component 801 and device component 803 may be disposed on the same surface of device component 802. In some examples, device component 801 and device component 803 may be disposed on the same surface of device component 802. 802 can be disposed on both ends of the first surface.

[0031] The device component 802 may include one or more grooves, such as groove 901. For example, at least one groove 901 may extend more than halfway through the device component 802, such as, but not limited to, in a direction perpendicular to the lower support structure 402. The length of the groove 901 may exceed the width of the groove 901. In other examples, the length of the groove 901 may be the same as or less than the width of the groove 901.

[0032] Groove 901 may be configured to impede the flow of unwanted acoustic energy from device component 803 and reflected energy from one or more mounting structures 401. For example, as shown in flow channel 808, unwanted acoustic energy may originate from device component 803, be reflected by one or more mounting structures 401, and then be prevented from reaching device component 801 by groove 901.

[0033] As shown in flow path 807, unwanted acoustic energy may originate from device component 803 and then reach device component 801, but may be blocked by groove 901.

[0034] As shown in flow path 805 , unwanted acoustic energy can originate from device component 802 , be reflected off a surface such as the bottom surface of device component 802 , and reach device component 801 .

[0035] If the reflectivity of acoustic energy at one or more mounting structures 401 is high or varies significantly with operating conditions such as temperature, stress, external magnetic fields, etc., then one or more mounting structures 401 may be configured with small, individual features. In this manner, this configuration may not only reduce unwanted acoustic energy coupling to device component 801, but may also reduce variations in acoustic energy coupling to device component 801 across various operating conditions.

[0036] The one or more mounting structures 401 may be disposed on a first surface, such as a bottom surface, of the second device component 802. In some examples, the one or more mounting structures 401 may be disposed adjacent to each other on the same side of the device component 802. In some examples, the one or more mounting structures 401 may be the same size and / or shape. The one or more mounting structures 401 may be disposed below the device component 803. At least one of the one or more mounting structures 401 may be disposed adjacent to, below, and / or near the outer edge of the groove 901. In some examples, there may be no mounting structure 401 with a direct line of sight from the device component 801. In this manner, this configuration may reduce the intensity of acoustic energy passing through the flow channel 805 and / or mitigate variations in unwanted acoustic energy coupled into the device component 801 over various operating conditions.

[0037] The lower support structure 402 may be coupled to a first surface, such as the bottom surface, of the second device component 802 via one or more mounting structures 401 .

[0038] 5A-5H show, in plan view, various groove designs according to one exemplary embodiment. The grooves may refer to the same grooves as those described above with respect to any of FIGS. 1-4. Any number and combination of these groove designs may be used for the grooves associated with any of the figures disclosed herein. As shown in these figures, Groove 901may be surrounded by one or more solid regions 1301 of device 100 or device 200.

[0039] FIG. 5A shows a square pattern arranged between solid regions 1301. Groove 901 FIG. 5B shows circular regions 1301 arranged between solid regions 1301. Groove 901 FIG. 5C shows a cross-shaped solid region 1301 disposed between the solid regions 1301. Groove 901 FIG. 5D shows a square array of solid regions 1301. Groove 901 FIG. 5E shows a partial circular shape disposed between solid regions 1301. Groove 901 For example, a convex groove pattern as shown in Figure 5E can be configured to reduce the magnitude of unwanted acoustic energy in the device component 801, resonator 101, or capacitively transduced bulk acoustic wave resonator 905. Figure 5F illustrates a hexagonal groove pattern disposed between solid regions 1301. Groove 901 FIG. 5G shows a polygonal region 1301 disposed between solid regions 1301. Groove 901 FIG. 5H shows a square pattern disposed between solid regions 1301. Groove 901 1 shows an example of dimensions. Groove 901 and solid region 1301 may be the same as or different from the respective regions shown in FIG. 5A. In some examples, a square Groove 901 may have a first x-axis dimension of about 775 microns and a second x-axis dimension of about 175 microns. Solid region 1301 may have a third x-axis dimension of about 2300 microns. In some examples, the depth of groove 901 region may be about 10-500 microns. As an example, Groove 901 The area inside is Groove 901 The range of the ratio of the area of ​​the outer surface of the Groove 901 It is understood that other values ​​for the ratio of the inner and outer areas are possible.

[0040] 5A to 5H Groove 901It will be understood that the groove patterns and / or shapes and / or sizes of the solid region 1301 are not limited to these groove patterns and / or shapes and / or sizes, and that any other groove patterns and / or shapes and / or sizes may be used to at least partially cancel acoustic waves that may or may not be reflected. In some examples, the groove patterns of Figures 5A-5H may be symmetrical with respect to the device component 801, the resonator 101, or the capacitively transduced bulk acoustic wave resonator 905. For example, one or more mounting structures 401 (including, but not limited to, soft die attach) may be attached to the device component 801, the resonator 101, or the capacitively transduced bulk acoustic wave resonator 905. Groove 901 5G , the asymmetric groove pattern may be configured to partially cancel reflected acoustic waves in the device component 801, the resonator 101, or the capacitively transduced bulk acoustic wave resonator 905 through destructive interference. In some examples, the asymmetric groove pattern as shown in FIG. 5G may achieve destructive interference of acoustic waves entering the resonator 101 through the anchor 106, which may further mitigate unwanted acoustic energy coupling into the resonator 101.

[0041] FIG. 6 shows a cross-sectional view of a device 300 according to one exemplary embodiment.

[0042] Figure 6 may reference the same components as device 100 described above with respect to Figures 1 and 2, device 200 described above with respect to Figures 3A-3B and 4, and the groove pattern described above with respect to Figure 5. For the sake of brevity, the description of the components of device 100 described above with respect to Figures 1 and 2, the components of device 200 described above with respect to Figures 3A-3B, and the groove pattern of Figure 5 that apply to Figure 6 will be omitted. While Figure 6 shows a single instance of a component of device 300, it will be understood that any number of the components of device 300 may be included.

[0043] Device 300 may include many of the same components as device 100 and / or device 200, but may differ in some aspects. Specifically, substrate 102 may be disposed above resonator 101. Cap structure 105 may be disposed below resonator 101. Cap structure 105 may include one or more grooves 901 and one or more cavities 904, each of which may be configured to impede one or more flow paths, which may or may not include reflections, of unwanted acoustic energy into resonator 101. For example, groove 901 and cavity 904 may be configured to mitigate the flow of unwanted acoustic energy into resonator 101 via flow paths 603 and 602, respectively. Cavity 904 may reside at least partially within the cap structure below the resonator.

[0044] In some examples, unwanted acoustic energy may originate from one or more bond pads 107 and be reflected off a surface, such as a side of the cap structure 105. The groove 901 may be located at a corner portion of the cap structure 105. The groove 901 may be located at an opposite end of the cavity 904. In some examples, acoustic energy coupling from the electrode 103 may pass through the channel 601, reflect off a surface, such as the top surface of the substrate 102, and enter the resonator 101.

[0045] Additionally, the cap structure 105 may be coupled to the lower support structure 402 via the bond pad 107 and one or more mounting structures 401. The one or more mounting structures 401 may be disposed on a first surface, such as a top surface, of the lower support structure 402. The one or more mounting structures 401 may be disposed on a second surface, such as a bottom surface of the bond pad 107. The bond pad 107 may be disposed on a surface, such as a bottom surface, of the cap structure 105. At least one of the one or more mounting structures 401 and / or bond pad 107 may be disposed adjacent to, below, and / or closer to an outer edge of the groove 901.

[0046] FIG. 7 shows a cross-sectional view of a device 300 according to one exemplary embodiment.

[0047] Figure 7 may reference the same components of device 100 described above with respect to Figures 1 and 2, device 200 described above with respect to Figures 3A-3B and 4, the groove pattern described above with respect to Figure 5, and device 300 described above with respect to Figure 6. For brevity, the description of the components of device 100 described above with respect to Figures 1 and 2, the components of device 200 described above with respect to Figures 3A-3B and 4, the groove pattern of Figure 5, and device 300 that apply to Figure 7 will be omitted. While Figure 7 shows a single instance of the components of device 300, it will be understood that any number of the components of device 300 may be included.

[0048] The device 300 may include many of the same components as the device 300 of FIG. 6, but may differ in some aspects. The resonator 101 may be dually connected to the substrate 102 and the cap structure 105. For example, the resonator 101 may be coupled to the substrate 102 via anchors 106, e.g., coupled to the bottom surface of the substrate 102 via anchors 106. Additionally, the resonator 101 may be coupled to the cap structure 105 via connections 1501, e.g., coupled to the top surface of the cap structure 105 via connections 1501. For example, the connections 1501 may refer to electrical connections. In some examples, the connections 1501 may include pillar structures that may be configured to provide anchor points and electrical connections. In some examples, the connections 1501 may be integrated with the cap structure 105.

[0049] Additionally, this disclosure further considers the design and configuration of optimal groove dimensions to minimize unwanted acoustic energy into the resonator 101. For certain device parameters, simulated optimum groove 901 width was approximately 50 microns. As shown in FIG. 8, graph 800 shows the figure of merit and Groove 901 401. For example, simulations have been performed that indicate optimal groove widths that minimize unwanted acoustic coupling. In some instances, the actual groove widths used may differ from the simulated optimal groove widths. More specifically, during simulation operation, drive modes are excited and sense modes are measured as a function of material properties of one or more mounting structures 401. Changing the material properties of one or more mounting structures 401 changes the acoustic reflectivity, which in turn changes the amplitude of the sense modes.

[0050] Because soft die attach materials have a low Young's modulus, the wavelength of acoustic waves within the die attach can be comparable to the thickness of the die attach. Therefore, under certain conditions, acoustic thin-film interference effects can be significant, resulting in high acoustic reflections and unwanted acoustic coupling. In some examples, the die attach can be distributed as a continuous pattern. In other examples, the die attach can be distributed as a set of individual lines or dots. Exemplary die attach patterns are shown in Figures 9A-9C. Note that the area coverage of the die attach is a trade-off between the mechanical reliability of the attachment and unwanted acoustic coupling. Figure 9A shows a die attach pattern with a 1301 solid region 1302 disposed between the solid regions 1301. Groove 901 9 shows a plan view of the die attach pattern 905. Groove 901 9B shows the solid regions 1301 arranged between the solid regions 1301. Groove 901 9C shows a plan view of a die attach pattern 915 disposed between solid regions 1301. Groove 901 9 shows a plan view of the die attach pattern 910. Groove 901 are positioned one or more sides of the

[0051] Throughout this specification and claims, the following terms have at least the meaning expressly associated therewith herein, unless the context clearly dictates otherwise: The term "or" shall mean an inclusive "or." Furthermore, the terms "a," "an," and "the" mean one or more unless specifically stated otherwise or unless it is clear from the context that a singular form is intended.

[0052] In this description, numerous specific details are set forth. However, it should be understood that implementations of the disclosed technology may be practiced without these specific details. In other instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure an understanding of this description. References to "some examples," "other examples," "one example," "one example," "various examples," "one embodiment," "one embodiment," "some embodiments," "exemplary embodiments," "various embodiments," "one implementation," "one implementation," "exemplary implementation," "various implementations," "some implementations," and the like indicate that implementations of the disclosed technology so described may include particular features, structures, or characteristics, but not all implementations necessarily include the particular features, structures, or characteristics. Furthermore, repeated use of the phrases "in one example," "in one embodiment," or "in one implementation" do not necessarily refer to the same example, embodiment, or implementation, but may.

[0053] As used herein, unless otherwise specified, the use of ordinal adjectives such as "first," "second," "third," etc. to describe a common object merely indicates that different instances of a similar object are being referred to and does not imply that the objects so described must be in a particular order in time, space, precedence, or in any other way.

[0054] While particular implementations of the disclosed technology have been described in connection with what are presently considered to be the most practical and diverse implementations, it is to be understood that the disclosed technology is not limited to the disclosed implementations, but rather is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0055] This specification uses examples to disclose particular implementations of the disclosed technology, including the best mode, and also to enable those skilled in the art to practice the disclosed technology, such as making and using a device or system, or performing any incorporated methods. The patentable scope of particular implementations of the disclosed technology is defined in the claims, and may include other examples that occur to those skilled in the art. Such other examples are within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims.

Claims

1. A substrate; a bulk acoustic wave resonator disposed on at least a first surface of the substrate; wherein the substrate includes one or more grooves configured to impede the flow of acoustic energy to the bulk acoustic wave resonator.

2. The device of claim 1 , wherein the bulk acoustic wave resonator comprises a bulk acoustic wave resonator gyroscope.

3. The device of claim 2 , further comprising one or more electrodes, wherein the bulk acoustic wave resonator gyroscope is capacitively transduced via the one or more electrodes.

4. The device of claim 3 , wherein the one or more electrodes include one or more peripheral electrodes.

5. The device of claim 1 , further comprising one or more attachment structures including one or more selected from the group of soft die attach, hard die attach, adhesive, stud bumps, or interposers.

6. The device of claim 1 , wherein the one or more mounting structures are disposed below the substrate.

7. 2. The device of claim 1, wherein the first dimension is smaller than the second dimension, the first dimension being defined by a first distance from a first end of the first groove to a second end of the second groove, and the second dimension being defined by a second distance from a third end of the first electrode to a fourth end of the second electrode.

8. The device of claim 2 further comprising an attachment structure comprising one or more selected from the group of soft die attach, hard die attach, adhesive, stud bumps, or an interposer.

9. The device of claim 2 , wherein the one or more mounting structures are disposed below the substrate.

10. 3. The device of claim 2, wherein the first dimension is smaller than the second dimension, the first dimension being defined by a first distance from a first end of the first groove to a second end of the second groove, and the second dimension being defined by a second distance from a third end of the first electrode to a fourth end of the second electrode.

11. comprising a plurality of device components; a first device component selected from the plurality of device components includes a plurality of grooves; A device, wherein a second device component selected from the plurality of device components is sensitive to acoustic energy, and the plurality of grooves are configured to impede the flow of the acoustic energy to the second device component.

12. The device of claim 11 , wherein the second device component is attached to a first surface of the first device component.

13. a mounting structure that is not directly visible to the second device component; a lower support structure coupled to the first device component via the mounting structure; The device of claim 11 further comprising:

14. The device of claim 11 , wherein the first device component includes a cavity disposed below the second device component, the second device component comprising a bulk acoustic wave resonator.

15. The device of claim 14 , wherein the bulk acoustic wave resonator is capacitively transduced by one or more electrodes.

16. A substrate; a resonator coupled to a first surface of the substrate, the resonator comprising a bulk acoustic wave resonator gyroscope capacitively transduced via one or more electrodes; a cap structure including one or more grooves configured to impede the flow of acoustic energy to the resonator and one or more cavities configured to impede the flow of acoustic energy to the resonator; A device comprising:

17. 17. The device of claim 16, wherein at least one groove selected from the one or more grooves is located near a corner portion of the cap structure.

18. 17. The device of claim 16, wherein at least one cavity selected from the one or more cavities is disposed within the cap structure at least partially below the resonator.

19. The device of claim 16 , wherein the cap structure is disposed below the substrate.

20. The device of claim 16 , wherein the resonator is coupled to a first surface of the cap structure.

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