SYSTEMS AND METHODS FOR ACOUSTICALLY ISOLATED RESONATORS

Systems and methods disclosed herein include a device with a bulk acoustic wave resonator and one or more trenches that are configured to impede the flow of acoustic energy to the bulk acoustic wave resonator.

TECHNICAL FIELD

The present disclosure relates to acoustically isolated resonators, and more particularly, to systems and methods for acoustically isolated bulk wave resonator gyroscopes.

BACKGROUND

The coupling of acoustic energy to a resonator can increase the noise of the resonator. Variation of coupled acoustic energy can cause variation in resonator output. This causes degradation of the resonator performance. These and other deficiencies exist.

BRIEF SUMMARY

Embodiments of the present disclosure provide a device that includes a substrate. The device may include a bulk acoustic wave resonator that is arranged on at least a first surface of the substrate. The substrate may include one or more trenches that are configured to impede the flow of acoustic energy to the bulk acoustic wave resonator.

Embodiments of the present disclosure provide a device that includes a plurality of device components. A first device component selected from the plurality of device components may comprise a plurality of trenches and/or cavities. A second device component selected from the plurality of device components may be sensitive to acoustic energy. The plurality of trenches are configured to impede the flow of the acoustic energy to the second device component.

Embodiments of the present disclosure provide a device that includes a substrate. The device may include a resonator that is coupled to a first surface of the substrate. The resonator may include a bulk acoustic wave resonator gyroscope that is capacitively transduced via one or more electrodes. The device may include a cap structure. The cap structure may include one or more trenches that are configured to impede the flow of the acoustic energy to the resonator. The cap structure may include one or more cavities that are configured to impede the flow of the acoustic energy to the resonator.

DETAILED DESCRIPTION

Acoustic energy may get coupled to a resonator and thereby degrade its performance. For example, the acoustic energy may increase the noise of the resonator, or impact the zero-rate-offset of a resonator-based gyroscope. Further, temperature-dependent acoustic energy coupling to the resonator may produce temperature dependent effects, for example, high-order zero-rate-offset versus temperature behavior. Besides temperature, the unwanted acoustic energy coupling may vary with other operating conditions, such as stress or external fields, which may degrade device performance. The sources of the unwanted acoustic energy may be internal or external to the device. The acoustic energy may be generated in the resonator and electrodes due to electrostatic transduction. Thus, in some examples, the resonator and the electrode may serve as severe sources of acoustic energy.

As used herein, unwanted acoustic energy may refer to acoustic energy, which may or may not be external to the resonator101, coupled to the anchor106, even if generated internal to the resonator101. Thus, unwanted acoustic energy may be generated from within the resonator101and/or the environment outside the resonator101, and thus is not limited to energy that is only external to the resonator101, and the trench(es), such as trench901, is configured to impede a flow, including but not limited to one or more flow paths, of the unwanted acoustic energy when bounced back, as further discussed herein. In some examples, unwanted acoustic energy may couple into the resonator101via structures, such as other than an anchor106, including but not limited to a connection1501(as depicted in, for example,FIG.7). In some examples, there may be unwanted acoustic energy coupling to the resonator101via a medium that surrounds the resonator. By way of example, the medium may refer to a gas, a liquid, and/or any combination thereof that is located around the resonator101. Without limitation, the medium may be external to the resonator101.

To mitigate these problems, the trenches and/or the cavities of the systems and method disclosed herein may be arranged to impede a flow, such as one or more flow paths, and reduce unwanted acoustic energy between drive and sense modes of a gyroscope, such as a bulk acoustic wave resonator gyroscope. Moreover, such an arrangement reduces zero-rate-offset and high-order zero-rate-offset vs. temperature behavior in resonant gyroscopes. Consequently, this yields enhancement in device performance.

FIG.1Adepicts a cross-sectional view of a device100according to an example embodiment. The device100may include a resonator101, a substrate102, an electrode103, a transduction gap104, a cap structure105, an anchor106, a bond pad107, a wire bond108, and one or more trenches901. AlthoughFIG.1Aillustrates single instances of the components of the device100, it is understood that any number of components of the device100may be included.

As further depicted inFIG.1A, acoustic energy may be supplied from several sources, such as sources110,115,120, and125that are external to the device100, source130due to motion of the wire bond108, source135due to motion of the bond pad107, source140due to motion of the substrate102, source145due to motion of the cap structure105, source150due to motion of the resonator, source155due to motion of the anchor106, and source160due to motion of the electrode103. The arrows depict motion of the sources145,150,155, and160but do not necessarily depict the direction of the motion, as the motion or vibration can occur in any direction, such as longitudinally, laterally, sideways, obliquely, tortuously, etc. As further described below, the device100may be configured to isolate the resonator101from unwanted acoustic energy and enhance its performance.

The resonator101may comprise a bulk acoustic wave resonator gyroscope. The bulk acoustic wave resonator may be arranged on at least a first surface of the substrate102. For example, the resonator101may be connected to the first surface of the substrate102via an anchor106. The resonator101may be capacitively transduced via the one or more electrodes103. In some examples, the one or more electrodes103may comprise one or more peripheral electrodes. In other examples, the one or more electrodes103may comprise one or more non-peripheral electrodes. In still other examples, the one or more electrodes103may comprise a peripheral electrode, a non-peripheral electrode, and/or any combination thereof. For example,FIG.1Billustrates a device100, which further includes a non-peripheral electrode109. In some examples, the non-peripheral electrode109may include a planar electrode. Capacitive transduction may occur between the non-peripheral electrode109and resonator101across gap111. Although FIG.1B illustrates single instances of the components of the device100, it is understood that any number of components of the device100may be included.FIG.1Bmay reference the same components of device100as discussed above with respect toFIG.1A. The transduction gap104may separate the resonator101from the one or more electrodes103. The transduction gap104may be disposed above the substrate102. For example, the transduction gap104may be disposed above the first surface of the substrate102.

The wire bond108may be coupled to the bond pad108. The bond pad108may be disposed on a first surface of the cap structure105. In some examples, the bond pad108may be disposed on opposite ends of the first surface of the cap structure105.

The substrate102may include one or more trenches901that are configured to impede a flow of unwanted acoustic energy to the bulk acoustic wave resonator. For example, the one or more trenches901may be symmetrically disposed within the substrate102. In another example, the one or more trenches901may be asymmetrically disposed within the substrate102. Moreover, the one or more trenches901may be of same shape or different shape than another trench901. Further, the one or more trenches901may be of same or different size than another trench901. For example, at least one trench901may extend more than halfway into the substrate102, including but not limited to in a direction perpendicular to the substrate102. The length of the trench901may exceed the width of the trench901. In other examples, the length of the trench901may be the same or smaller than the width of the trench901.

The one or more trenches901may be configured to impede the flow of unwanted acoustic energy to the resonator101. In some examples, the presence of the one or more trenches901may be configured to impede a flow of unwanted acoustic energy, such as one or more flow paths302,303,304, and/or305, to the resonator101via anchor106. As depicted inFIGS.1A-1B, acoustic energy originating at one or more of the electrodes103or cap structure105may traverse respective direct flow paths303,305to the resonator101. The acoustic energy originating at one or more of the electrodes103or cap structure105may traverse respective flow paths302,304to the resonator101after one or more reflections, such as a reflection against a second surface, such as the bottom surface, of the substrate102. It is understood that the reflection not be limited to only a single reflection or with respect to the second surface of the substrate102, and that additionally or alternatively, any number of reflections and/or any number of surfaces of the substrate102may be reflected against to constitute a flow path for the acoustic energy to traverse to the resonator101.

The one or more trenches901may 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. Moreover, any number of the walls of trenches901may be straight, tapered, rounded, corrugated, undulating, and/or any combination thereof.

The resonator101may be configured to resonate in a plurality of modes, such as a first mode and a second mode. Under the first mode, such as a drive mode, this may correspond to vibration along a first axis, whereas under the second mode, such as a sense mode, that may correspond to vibration along a second axis and thus these modes are orthogonal to each other. It is generally desirable for the frequencies of the drive and sense modes to match, as this may tend to increase signal-to-noise ratio of the resonator101. For example, an angular rate gyroscope may be configured to operate in a mode-matching 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 drive and sense modes may occur via flow path301. In this manner, acoustic energy originating at the resonator101due to drive mode excitation may traverse flow path301and get coupled back to the sense mode of the resonator101. In mode-matched configuration, the impact of such coupling is especially deleterious as both modes are nominally at about the same frequency thereby resulting in efficient coupling of unwanted acoustic energy.

The cap structure105may be configured to at least partially encompass the resonator101. The transduction gap104may include a separation or gap between the resonator101and one or more electrodes103. In some examples, the device100may include two or more transduction gaps104. For example, two transduction gaps104may be diametrically opposite to each other, and may be each relative to the resonator101and different electrodes103. The resonator101and the one or more electrodes103may be formed in, for example, a base portion of the device100, and the base portion may be bonded to the cap structure105. The cap structure105may be disposed above the substrate102. For example, the cap structure105may be disposed above the first surface of the substrate102.

FIG.2depicts a cross-sectional view of a device100according to another example embodiment.FIG.2may reference the same components of device100as discussed above with respect toFIGS.1A-1B. For purposes of brevity, the description of the components of device100discussed above with respect toFIGS.1A-1Bas applied toFIG.2is omitted. AlthoughFIG.2illustrates single instances of the components of the device100, it is understood that any number of components of the device100may be included. The device100may include one or more attachment structures401. For example, at least one of the attachment structures401may be disposed below a second surface, such as the bottom surface, of the substrate102. The one or more attachment structures401may include one or more selected from the group of: a soft die attach, a hard die attach, an adhesive, a stud bump, an interposer, and/or any combination thereof. In particular, soft materials, including but not limited to a soft-die, may be used to avoid buildup of stress when temperature changes. For example, soft-die attach material may be utilized to minimize thermal and packaging stresses acting on the MEMS die. When selecting a type of die attach, there is consideration for a tradeoff between stress effect and reliability, as the softer the die attach, the less reliable it is likely to be. Absent the utilization of trenches in the resonator101, the problem regarding unwanted acoustic energy exists (as discussed herein), but the factors for consideration in selecting the soft die attach include lower stress during packaging and operation across a range of temperatures. In some examples, die attach thickness values may range from a few microns to a few hundred microns. For example, the die attach thickness value may comprise 50 microns.

In some examples, the one or more attachment structures401may be disposed at opposite ends of the substrate102. For example, the one or more attachment structures401may be disposed symmetrically with respect to the opposite ends of the substrate102. The one or more attachment structures401may include a width that is shorter than an end of the substrate102that it is coupled to. In other example, the one or more attachment structures401may include a width that is longer than an end of the substrate102that it is coupled to. In some examples, the one or more attachment structures401may be disposed adjacent or closer to an outer edge, as opposed to an inner edge, of the one or more trenches901.

The device100may include one or more underlying support structures402. In some examples, the device100may include a single underlying support structure402. For example, the underlying support structure402may be disposed between the one or more attachment structures401. In some examples, the underlying support structure may extend longer than the length of each of the substrate102and cap structure105. The one or more underlying support structures402may include at least one selected from the group of an integrated circuit, a printed circuit board, a package, an interposer, or the like.

As further depicted inFIG.2, a first dimension1201may be smaller than a second dimension1202, and relative to a direction parallel to the one or more underlying support structures402. For example, the first dimension1201may be defined by a first distance from a first end, such as an outer edge, of a first trench901to a second end, such as an outer edge, of a second trench901. In some examples, the outer edges of the trench901may include edges that are furthest away relative to the resonator101. The second dimension1202may be defined by a second distance from a third end, such as an inner end of a first electrode103to a fourth end, such as an inner end of a second electrode103. In some examples, the inner ends of the electrodes103may include ends that are closed to the resonator101. In some examples, the device100may include two or more transduction gaps104that may be diametrically opposite to each other, and may be each relative to the resonator101and different electrodes103. In some examples, selecting the first dimension1201as being smaller than the second dimension1202may impede unwanted acoustic energy flow via flow paths302,303, and305.

FIGS.3A-3Beach depict a cross-sectional view of a device200according to an example embodiment.FIGS.3A-3Bmay reference the same components of device100as discussed above with respect toFIGS.1and2. For purposes of brevity, the description of the components of devices100discussed above with respect toFIGS.1and2as applied toFIG.3is omitted. AlthoughFIGS.3A-3Billustrates single instances of the components of the device200, it is understood that any number of components of the device200may be included.

As illustrated inFIG.3A, the device200may include a plurality of device components801,802, and803. For example, the device component801and the device component803may be disposed on the same surface of the device component802. In some examples, the device component801and the device component803may be disposed on opposite ends of a first surface of the device component802.

At least one of the device components, such as the device component802, selected from the plurality of device components801,802, and803may comprise a plurality of trenches901,902,903, and904. At least one of the device components, such as the device component801, may be sensitive to unwanted acoustic energy. The plurality of trenches901,902,903, and904may be configured to impede a flow of the unwanted acoustic energy to the device component801. The device component801may be separated from the device component803by at least one trench, such as trench902. In some examples, the trench901may be of a different size and/or shape as the trenches902,903, and904. As previously explained, the unwanted acoustic energy may be supplied from any of several sources that are external and/or internal to the device200.

The plurality of trenches901,902,903, and904may 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. Moreover, any number of the walls of trenches901,902,903, and904may be straight, tapered, rounded, corrugated, undulating, and/or any combination thereof.

As illustrated inFIG.3B, the device200may include a plurality of device components801,802, and803, just as depicted inFIG.3A. In addition, at least one of the device components801may comprise a bulk acoustic wave resonator905that is capacitively transduced by one or more electrodes. Thus, the device200may include a bulk acoustic wave resonator905that is capacitively transduced by one or more electrodes, such as one or more peripheral electrodes. In addition, the device200may include a cavity904. For example, the device component802may be configured to include a cavity904that is disposed below the bulk acoustic wave resonator905. The cavity904may be configured to impede the flow of the acoustic energy into the bulk acoustic wave resonator905. The cavity904may be adjacent to at least one of the trenches, such as trench902. The cavity904may be of any size and/or shape. In effect, the plurality of trenches901,902,903, and904and one or more cavities904may be configured to mitigate the unwanted acoustic energy flow into the bulk acoustic wave resonator905.

FIG.4depicts a cross-sectional view of a device200according to an example embodiment.FIG.4may reference the same components of device100as discussed above with respect toFIGS.1and2, and device200as discussed above with respect toFIGS.3A-3B. For purposes of brevity, the description of the components of devices100discussed above with respect toFIGS.1and2, and the components of devices200as discussed above with respect toFIGS.3A-3Bas applied toFIG.4is omitted. AlthoughFIG.4illustrates single instances of the components of the device200, it is understood that any number of components of the device200may be included.

The device200may include a plurality of device components801,802, and803, one or more attachment structures401, and one or more underlying support structures402. For example, the device component801and the device component803may be disposed on the same surface of the device component802. In some examples, the device component801and the device component803may be disposed on opposite ends of a first surface of the device component803.

The device component802may comprise one or more trenches, such as trench901. For example, at least one trench901may extend more than halfway into the device component802, including but not limited to in a direction perpendicular to the underlying support structure402. The length of the trench901may exceed the width of the trench901. In other examples, the length of the trench901may be the same or smaller than the width of the trench901.

The trench901may be configured to impede the flow of unwanted acoustic energy from device component803and reflected energy from the one or more attachment structures401. For example, as indicated in flow path808, the unwanted acoustic energy may originate from device component803which is reflected by the one or more attachment structures401before it is impeded by the trench901that is destined to reach the device component801.

As indicated in flow path807, the unwanted acoustic energy may originate from device component803before it is impeded by the trench901that is destined to reach the device component801.

As indicated in flow path805, the unwanted acoustic energy may originate from the device component802which is reflected by a surface, such as the bottom surface, of the device component802that is destined to reach the device component801.

If the acoustic energy reflectivity at the one or more attachment structures401is high or varies significantly with operating conditions, such as temperature, stress, an external magnetic field, or the like, the one or more attachment structures401may be configured with small discrete geometries. In this manner, this configuration may mitigate unwanted acoustic energy coupling to device component801, as well as variation of the acoustic energy coupling to device component801across the range of operating conditions.

The one or more attachment structures401may be disposed on a first surface, such as a bottom surface, of the second device component802. In some examples, the one or more attachment structures401may be disposed adjacent to each other on the same side of the device component802. In some examples, the one or more attachment structures401may be of the same size and/or shape. The one or more attachment structures401may be disposed below the device component803. At least one of the one or more attachment structures401may be disposed adjacent, below, and/or close to an outer edge of the trench901. In some examples, there may be no attachment structure401that is in a direct line-of-sight from the device component801. In this manner, this configuration may reduce the intensity of acoustic energy traversing the flow path805and/or mitigate variation of unwanted acoustic energy coupled to the device component801across the range of operating conditions.

The underlying support structure402may be coupled to the first surface, such as the bottom surface, of the second device component802via the one or more attachment structures401.

FIGS.5A-5Hillustrate various designs of a trench in a plan view according to an example embodiment. The trench may refer to the same trench as previously described above with respect to any ofFIGS.1-4. Any number and any combination of these trench designs may be used for the trenches in connection with any figures disclosed herein. As depicted in these figures, a trench region901may be surrounded by one or more solid regions1301of the device100or device200.

FIG.5Aillustrates a square trench region901that is disposed between solid regions1301.FIG.5Billustrates a circular trench region901that is disposed between solid regions1301.FIG.5Cillustrates a cross trench region901that is disposed between solid regions1301.FIG.5Dillustrates a square trench region901that is disposed inside a solid region1301.FIG.5Eillustrates partially circular trench regions901that are disposed between solid regions1301. For example, a convex trench pattern, as depicted inFIG.5E, may be configured to reduce a magnitude of unwanted acoustic energy at the device component801, resonator101, or the capacitively transduced bulk acoustic wave resonator905.FIG.5Fillustrates a hexagonal trench region901that is disposed between solid regions1301.FIG.5Gillustrates a polygonal trench region901that is disposed between solid regions1301.FIG.5Hillustrates an example dimensions of a square trench region901that is disposed between solid regions1301. The trench region901and solid regions1301may be the same or different as the respective regions illustrated inFIG.5A. In some examples, the square trench region901may include about 775 microns in a first x dimension, and 175 microns in a second x dimension. The solid region1301may include about 2300 microns in a third x dimension. In some examples, the trench901region may be about 10-500 microns deep. By way of example, a range of a ratio relative to the area inside the region901and the area outside the region901may comprise approximately 0.03-0.09. However, it is understood that other values for the ratio relative to the respective areas inside and outside the region901are contemplated.

It is understood that the trench regions901and the solid regions1301ofFIGS.5A-5Hare not limited to only these trench patterns and/or shapes and/or sizes, and that any other trench patterns and/or shapes and/or sizes may be used in order to at least partially cancel acoustic waves that may or may not be reflected. In some examples, the trench patterns ofFIGS.5A-5Hmay be symmetric with respect to the device component801, resonator101, or the capacitively transduced bulk acoustic wave resonator905. For example, by having the one or more attachment structures401(including but not limited to a soft-die attach) in contact with region1301outside the trench region901, unwanted acoustic energy flow, from the one or more attachment structures401to the resonator101, may be impeded. In other examples, the trench patterns ofFIGS.5A-5Hmay be asymmetric with respect to the device component801, resonator101, or the capacitively transduced bulk acoustic wave resonator905. For example, an asymmetric trench pattern may be configured to partially cancel reflected acoustic waves at the device component801, resonator101, or the capacitively transduced bulk acoustic wave resonator905by destructive interference, as shown inFIG.5G. In some examples, the asymmetric arrangement of the trench patterns, as shown inFIG.5G, may achieve destructing interference of acoustic waves entering the resonator101via an achor106, and this destructive interference may result in further mitigation of unwanted acoustic energy coupling to the resonator101.

FIG.6illustrates a cross-sectional view of a device300according to an example embodiment.

FIG.6may reference the same components of device100as discussed above with respect toFIGS.1and2, device200as discussed above with respect toFIGS.3A-3BandFIG.4, and the trench patterns as discussed above with respect toFIG.5. For purposes of brevity, the description of the components of devices100discussed above with respect toFIGS.1and2, and the components of devices200as discussed above with respect toFIGS.3A-3B, and trench patterns ofFIG.5as applied toFIG.6is omitted. AlthoughFIG.6illustrates single instances of the components of the device300, it is understood that any number of components of the device300may be included.

While the device300may include many of the same components as device100and/or device200, it may differ in a few aspects. In particular, the substrate102may be disposed above the resonator101. The cap structure105may be disposed below the resonator101. The cap structure105may include one or more trenches901and one or more cavities904that may be configured to each impede one or more flow paths of unwanted acoustic energy that may or may not include reflections to the resonator101. For example, the trench901and cavity904may be configured to mitigate the flow of unwanted acoustic energy to the resonator101via flow paths603and602, respectively. The cavity904may be at least in the cap structure at least partially below the resonator.

In some examples, the unwanted acoustic energy may originate from the one or more bond pads107that may be reflected against a surface, such as a side surface, of the cap structure105. The trench901may be arranged at a corner portion of the cap structure105. The trench901may be disposed at an opposite end of the cavity904. In some examples, the acoustic energy coupling may traverse flow path601from the electrode103, reflect from a surface, such as a top surface, of the substrate102and into resonator101.

In addition, the cap structure105may be coupled to the underlying support structure402via the bond pad107and one or more attachment structures401. The one or more attachment structures401may be disposed on a first surface, such as the top surface, of the underlying support structure402. The one or more attachment structures401may be disposed on a second surface, such as the bottom surface of the bond pad107. The bond pad107may be disposed on a surface, such as on the bottom surface, of the cap structure105. At least one of the one or more attachment structures401and/or the bond pad107may be disposed adjacent, below, and/or closer to an outer edge of the trench901.

FIG.7illustrates a cross-sectional view of a device300according to an example embodiment.

FIG.7may reference the same components of device100as discussed above with respect toFIGS.1and2, device200as discussed above with respect toFIGS.3A-3BandFIG.4, the trench patterns as discussed above with respect toFIG.5, and the device300as discussed above with respect toFIG.6. For purposes of brevity, the description of the components of devices100discussed above with respect toFIGS.1and2, the components of devices200as discussed above with respect toFIGS.3A-3BandFIG.4, the trench patterns ofFIG.5, and device300as applied toFIG.7is omitted. AlthoughFIG.7illustrates single instances of the components of the device300, it is understood that any number of components of the device300may be included. While the device300may include many of the same components as device300ofFIG.6, it may differ in a few aspects. The resonator101may be dually connected to the substrate102and the cap structure105. For example, the resonator101may be coupled to the substrate102via the anchor106, such as to the bottom surface of the substrate102via the anchor106. In addition, the resonator101may be coupled to the cap structure105via a connection1501, such as to an upper surface of the cap structure105via the connection1501. For example, the connection1501may refer to an electrical connection. In some examples, connection1501may comprise a pillar structure that may be configured to provide an anchoring point and an electrical connection. In some examples, the connection1501may be integrated with cap structure105.

In addition, the present disclosure further considers the design and configuration of optimal trench dimensions that minimize unwanted acoustic energy to the resonator101. For certain device parameters, a simulated optimal value of trench901width was about 50 microns. As illustrated inFIG.8, a graph800illustrates a figure of merit and width of the trench region901. For example, simulations conducted show an optimal value of trench width that minimized unwanted acoustic coupling. In some examples, the actual trench width used may be different from the simulated optimal value of trench width. More particularly, under operation of the simulations, the drive mode is excited and the sense mode is measured as a function of material properties of the one or more attachment structures401. As the material property of the one or more attachment structures401is changed, the acoustic reflectivity is changed, and therefore the amplitude of the sense mode changes.

As the soft-die attach material have a low Young's modulus, the wavelength of acoustic waves in the die attach may be comparable to die attach thickness. Thus, acoustic thin-film interference effects may be prominent under certain conditions that result in high acoustic reflection and unwanted acoustic coupling. In some examples, the die attach may be distributed as a continuous pattern. In other examples, the die attach may be distributed as a set of discrete lines or dots. Exemplary die attach patterns are illustrated inFIGS.9A-9C. It is noted that the area coverage of the die attach is a tradeoff between mechanical reliability of the attachment and unwanted acoustic coupling.FIG.9Aillustrates a plan view of a trench region901that is disposed between solid regions1301, in which die attach pattern905is disposed continuously around relative to the trench region901.FIG.9Billustrates a plan view of a trench region901that is disposed between solid regions1301, in which die attach pattern915is disposed at one or more edges or corners of the solid regions1301.FIG.9Cillustrates a plan view of a trench region901that is disposed between solid regions1301, in which die attach pattern910is disposed at one or more sides relative to the trench region901.

In this description, numerous specific details have been set forth. It is to be understood, however, 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 in order not to obscure an understanding of this description. References to “some examples,” “other examples,” “one example,” “an example,” “various examples,” “one embodiment,” “an embodiment,” “some embodiments,” “example embodiment,” “various embodiments,” “one implementation,” “an implementation,” “example implementation,” “various implementations,” “some implementations,” etc., indicate that the implementation(s) of the disclosed technology so described may include a particular feature, structure, or characteristic, but not every implementation necessarily includes the particular feature, structure, or characteristic. Further, repeated use of the phrases “in one example,” “in one embodiment,” or “in one implementation” does not necessarily refer to the same example, embodiment, or implementation, although it may.