TW202107845A - Bulk-acoustic wave resonator - Google Patents

Abstract

A bulk-acoustic wave resonator includes: a substrate; a lower electrode disposed on the substrate; a piezoelectric layer at least partially covering the lower electrode; and an upper electrode at least partially covering the piezoelectric layer. On a surface of the bulk-acoustic wave resonator, a centroid of an active area in which the lower electrode, the piezoelectric layer, and the upper electrode all overlap each other is aligned with a center of a rectangle defining an aspect ratio of the active area. The active area has a shape of a polygon symmetrical with respect to at least one axis passing through the center of the rectangle defining the aspect ratio. The aspect ratio is greater than or equal to 2 and less than or equal to 10.

Description

Bulk acoustic resonator

The following description is about a bulk acoustic resonator. [Cross reference of related applications]

This application claims the priority of Korean patent application No. 10-2019-0093323 and No. 10-2020-0031588 filed in the Korea Intellectual Property Office on July 31, 2019 and March 13, 2020, respectively Rights, all disclosures of the Korean patent application are incorporated into this case for reference for all purposes.

A bulk acoustic wave (BAW) filter is, for example, a core component in a front-end module (such as a smart phone, a desktop personal computer (PC), or the like). The BAW filter allows radio frequency (RF) signals in the desired frequency band to pass through it, while blocking signals in the undesired frequency band. With the recent growth of the mobile device market, and especially the recent development of the 5th generation (5G) communication frequency band, the demand for BAW filters is increasing.

In order to keep up with the future development of the 5G communication frequency band market, the frequency used in the BAW filter should be higher. In this case, since the total thickness of the resonator should be equal to half of the vertical wave, when the frequency increases, the total thickness of the resonator should decrease. Therefore, since the thickness of the lower electrode and the upper electrode provided in the resonator becomes thinner in high-frequency applications, when relatively high power is applied, the heat dissipation properties may be problematic, or the quality factor at the resonance point (Q) The performance may be reduced, thereby deteriorating the insertion loss (IL) performance of the resonator.

To solve these problems, the aspect ratio (AR) of the resonator can be increased, and current can be allowed to flow in the uniaxial direction of the resonator. For example, the aspect ratio of the shape of the resonator can be increased, and current can be allowed to flow in the uniaxial direction of the resonator to reduce the resistance loss at the resonance point.

However, when the aspect ratio of the resonator increases, there may be a problem of deterioration in Q performance.

The content of the present invention is provided to introduce a series of concepts further elaborated in the following embodiments in a simplified form. The content of the present invention is not intended to identify the key features or essential features of the claimed subject matter, nor is it intended to be used to help determine the scope of the claimed subject matter.

In a general aspect, a bulk acoustic wave resonator includes: a substrate; a lower electrode provided on the substrate; a piezoelectric layer at least partially covering the lower electrode; and an upper electrode at least partially covering the pressure Electric layer. On the surface of the bulk acoustic wave resonator, the centroid of the active area where the lower electrode, the piezoelectric layer, and the upper electrode all overlap each other is aligned with the center of the rectangle defining the aspect ratio of the active area . The active area has a polygonal shape that is symmetrical with respect to at least one axis passing through the center of the rectangle defining the aspect ratio. The aspect ratio is greater than or equal to 2 and less than or equal to 10.

The rectangle defining the aspect ratio may be a rectangle having the largest aspect ratio among rectangles contacting three or more vertices of the polygon.

The polygon may be a polygon with N angles, where N is an even number greater than or equal to 4.

The bulk acoustic resonator may further include a film layer forming a cavity together with the substrate.

The bulk acoustic wave resonator may further include an etching prevention part provided to surround the cavity.

The bulk acoustic wave resonator may further include a sacrificial layer provided outside the etching prevention portion.

The bulk acoustic resonator may further include an insertion layer at least partially disposed between the lower electrode and the piezoelectric layer.

The bulk acoustic wave resonator may further include a passivation layer provided to expose a portion of the lower electrode and a portion of the upper electrode.

The bulk acoustic wave resonator may further include a metal pad contacting the exposed part of the lower electrode and the exposed part of the upper electrode.

In another general aspect, a bulk acoustic resonator includes: a substrate; a lower electrode provided on the substrate; a piezoelectric layer at least partially covering the lower electrode; and an upper electrode at least partially covering the Piezoelectric layer. The centroid of the active area where the lower electrode, the piezoelectric layer, and the upper electrode all overlap each other matches the first axis coordinate value of the center of the rectangle defining the aspect ratio of the active area, and the active area The centroid of does not match the second axis coordinate value of the center of the rectangle defining the aspect ratio of the active area. The first axis coordinate value is relative to the coordinate value of the first axis of the rectangle that defines the aspect ratio, and the second axis coordinate value is relative to the second axis of the rectangle that defines the aspect ratio. The coordinate value of the axis. The bulk acoustic wave resonator satisfies h/y'<0.067, y'is the separation distance between the centroid of the active region and the center of the rectangle in the direction of the second axis, and h is the length of the active area in the direction of the second axis.

The active area may be symmetrical with respect to the first axis.

The rectangle defining the aspect ratio may be a rectangle having the largest aspect ratio among rectangles contacting three or more vertices of the peripheral shape of the active region.

The bulk acoustic wave resonator may further include an insertion layer partially disposed between the lower electrode and the piezoelectric layer.

The insertion layer may have a ring shape.

In another general aspect, a bulk acoustic resonator includes: a lower electrode provided on a substrate; a piezoelectric layer provided on the lower electrode; and an upper electrode provided on the piezoelectric layer. The perimeter of the active area where the lower electrode, the piezoelectric layer, and the upper electrode all overlap each other has a polygonal shape with respect to at least one passing through the center of the rectangle defining the aspect ratio of the polygon Axisymmetric. The centroid of the polygon is aligned with the center of the rectangle defining the aspect ratio. The aspect ratio is greater than or equal to 2 and less than or equal to 10.

The at least one shaft may include only one shaft.

The polygon may be any one of a rhombus, a hexagon and an octagon.

The aspect ratio may be greater than or equal to 2.4 and less than or equal to 5.6.

The rectangle defining the aspect ratio may be a rectangle having the largest aspect ratio among rectangles contacting three or more vertices of the polygon.

In another general aspect, a bulk acoustic resonator includes: a lower electrode provided on a substrate; a piezoelectric layer provided on the lower electrode; and an upper electrode provided on the piezoelectric layer. The active area where the lower electrode, the piezoelectric layer, and the upper electrode all overlap each other has a polygonal shape. The centroid of the polygon matches the first axis coordinate value of the center of the rectangle defining the aspect ratio of the polygon, and the centroid of the active area matches the rectangle defining the aspect ratio of the polygon The second axis coordinate value of the center does not match. The first axis coordinate value is relative to the coordinate value of the first axis of the rectangle that defines the aspect ratio, and the second axis coordinate value is relative to the second axis of the rectangle that defines the aspect ratio. The coordinate value of the axis. The bulk acoustic wave resonator satisfies y'/h<0.067, y'is the separation distance between the centroid of the active region and the center of the rectangle in the direction of the second axis, and h is the length of the active area in the direction of the second axis.

The active area may be symmetrical with respect to the first axis.

The polygon may be a hexagon.

By reading the following detailed description, drawings and the scope of patent application, other features and aspects will be obvious.

The following detailed description is provided to help readers fully understand the methods, equipment and/or systems described in this article. However, after understanding the disclosed content of this application, various changes, modifications, and equivalent forms of the methods, devices, and/or systems described herein will be obvious. For example, the order of operations described herein is only an example, and is not limited to the order of operations described herein, but as will be obvious after understanding the disclosure of this application, except for operations that must occur in a certain order, Can be changed. In addition, in order to increase clarity and conciseness, descriptions of known features in the art may be omitted.

The features set forth herein can be implemented in different forms and should not be construed as being limited to the examples described herein. To be precise, the examples described herein are only provided to illustrate some of the many possible ways of implementing the methods, devices, and/or systems described herein, which will be apparent after understanding the disclosure of this application. .

Note that the use of the term "may" with respect to an example or embodiment herein (for example, regarding what the example or embodiment may include or implement) means that there is at least one example or embodiment in which such a feature is included or implemented, and all Examples and embodiments are not limited to this.

In the specification, when an element such as a layer, region, or substrate is described as being "on", "connected to", or "coupled to" another element, the element can be directly "located" on the other element. An element is "on", directly "connected to" or directly "coupled to" the other element, or there may be one or more other elements in between. Conversely, when an element is described as being "directly on", "directly connected to" or "directly coupled to" another element, there may be no intervening elements.

The term "and/or" as used herein includes any one of the associated listed items or any combination of any two or more.

Although terms such as "first", "second" and "third" may be used in this article to describe various components, components, areas, layers or sections, these components, components , Zone, layer or section are not restricted by these terms. To be precise, these terms are only used to distinguish individual components, components, regions, layers or sections. Therefore, without departing from the teachings of the examples, the first member, component, region, layer, or section mentioned in the examples described herein can also be referred to as a second member, component, region, layer, or Section.

For ease of explanation, this article may use spatially relative terms such as "above", "upper", "below", "lower", "front", "back", and "side" to describe the one shown in the figure. The relationship between a component and another component. Such spatially relative terms are intended to cover the different orientations of the device in use or operation in addition to the orientations shown in the figure. For example, if the device in the figure is turned over, the element described as being "above" or "upper" with respect to another element will now be "below" or "lower" with respect to the other element. Therefore, the term "above" depends on the spatial orientation of the device and encompasses both the top and bottom orientations. As another example, if the device in the figure is turned over, it is stated that the element located "in front" relative to another element will now be located "rearward" relative to the other element. Therefore, the term "front" is based on the spatial orientation of the device and encompasses both front and rear orientations. The device can also be oriented in other ways (for example, rotated by 90 degrees or in other orientations), and the terms of spatial relativity used herein shall be explained accordingly.

The terminology used herein is only to illustrate various examples, and is not used to limit the content of this disclosure. Unless the context clearly dictates otherwise, the articles "一 (a, an)" and "the" are intended to also include plural forms. The terms "comprises", "includes" and "has" specify the existence of stated features, numbers, operations, components, elements, and/or combinations thereof, but do not exclude one or more other The existence or addition of features, numbers, operations, components, elements, and/or combinations thereof.

Due to manufacturing technology and/or tolerances, the shapes shown in the drawings may be deformed. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings, but include shape changes that occur during manufacturing.

As will be apparent after understanding the disclosure of this application, the features of the examples described herein can be combined in various ways. In addition, although the examples described herein have various configurations, as will be apparent after understanding the disclosure of this application, other configurations may exist.

FIG. 1 is a schematic plan view showing a bulk acoustic wave resonator 100 according to the embodiment. Fig. 2 is a cross-sectional view taken along the line I-I' shown in Fig. 1. Fig. 3 is a cross-sectional view taken along the line II-II' shown in Fig. 1.

1 to 3, the bulk acoustic wave resonator 100 may include, for example, a substrate 110, a sacrificial layer 120, an etching prevention portion 130, a lower electrode 150, a piezoelectric layer 160, an upper electrode 170, an insertion layer 180, a passivation layer 190, and a metal connection. Pad 195.

The substrate 110 may be a silicon substrate. For example, the substrate 110 may be a silicon wafer or a silicon-on-insulator (SOI) type substrate.

The insulating layer 112 may be formed on the upper surface of the substrate 110 and may electrically isolate the substrate 110 from the structure disposed thereon. In addition, when the cavity C is formed during the manufacturing process, the insulating layer 112 can prevent the substrate 110 from being etched by the etching gas.

In this example, the insulating layer 112 may be _{any one or two of silicon dioxide (SiO 2} ), silicon nitride (Si ₃ N ₄ ), aluminum oxide (Al ₂ O ₃ ), and aluminum nitride (AlN). Any combination of one or more. The insulating layer 112 may be formed on the substrate 110 by any one of a chemical vapor deposition process (chemical vapor deposition process), an RF magnetron sputtering process (RF magnetron sputtering process), and an evaporation process (evaporation process).

The sacrificial layer 120 may be formed on the insulating layer 112, and the cavity C and the etching prevention part 130 may be disposed in the sacrificial layer 120. For example, the cavity C can be formed by removing part of the sacrificial layer 120 during the manufacturing process. Therefore, since the cavity C is formed in the sacrificial layer 120, the lower electrode 150 and other layers disposed on the sacrificial layer 120 may be formed to be planar or substantially planar.

The etching prevention part 130 may be provided along the boundary of the cavity C. The etching prevention part 130 may prevent the etching from proceeding beyond the region of the cavity in the operation of forming the cavity C.

The portion of the lower electrode 150 may be disposed on the upper portion of the cavity C. In addition, the lower electrode 150 can be configured as an input electrode or an output electrode for respectively inputting or outputting electrical signals such as radio frequency (RF) signals or the like.

For example, the lower electrode 150 may be formed of a conductive material such as molybdenum (Mo) or an alloy of Mo. However, the lower electrode is not limited to being formed of Mo, and may be, for example, ruthenium (Ru), tungsten (W), iridium (Ir), platinum (Pt), copper (Cu), titanium (Ti), tantalum (Ta), nickel ( It is formed of conductive materials such as Ni), chromium (Cr) and the like, or alloys of Ru, W, Ir, Pt, Cu, Ti, Ta, Ni, or Cr.

The piezoelectric layer 160 may be formed to at least partially cover the portion of the lower electrode 150 provided on the upper portion of the cavity C. The piezoelectric layer 160 may be a layer that generates a piezoelectric effect that converts electrical energy into mechanical energy in the form of elastic waves, and may be aluminum nitride (AlN), zinc oxide (ZnO), or lead zirconate titanate oxide ( Any one of PbZrTiO, PZT) is formed. For example, when the piezoelectric layer 160 is formed of aluminum nitride (AlN), the piezoelectric layer 160 may further include rare earth metals. For example, the rare earth metal may include any one of scandium (Sc), erbium (Er), yttrium (Y), and lanthanum (La), or any combination of any two or more. In addition, as an example, the transition metal may include any one of titanium (Ti), zirconium (Zr), hafnium (Hf), tantalum (Ta), and niobium (Nb), or any combination of any two or more. In addition, the divalent metal magnesium (Mg) may also be included.

The piezoelectric layer 160 may include a piezoelectric portion 162 and a curved portion 164. The piezoelectric portion 162 is disposed in a plane section S generally located in the central area of the piezoelectric layer 160, and the curved portion 164 is disposed outside the plane section S. Extend section E.

The piezoelectric part 162 may be a part directly stacked on the upper surface of the lower electrode 150. Therefore, the piezoelectric part 162 may be sandwiched between the lower electrode 150 and the upper electrode 170 to form a planar shape together with the lower electrode 150 and the upper electrode 170.

The bent portion 164 may be a portion extending outward from the piezoelectric portion 162 and located in the extension section E.

The bent portion 164 may be provided on the insertion layer 180 which will be explained later, and may be formed to have a shape that rises with the shape of the insertion layer 180. Therefore, the piezoelectric layer 160 may be bent at the boundary between the piezoelectric portion 162 and the bent portion 164, and the bent portion 164 may be raised corresponding to the thickness and shape of the insertion layer 180.

The curved portion 164 may include an inclined portion 164a and an extended portion 164b.

The inclined portion 164a is, for example, a portion formed to be inclined along an inclined surface L of the insertion layer 180 to be explained later. In addition, the extending portion 164b is, for example, a portion extending outward from the inclined portion 164a.

The inclined portion 164a may be formed to be parallel to the inclined surface L of the insertion layer 180, and the inclined angle of the inclined portion 164a may be formed to be the same as the inclined angle θ of the inclined surface L of the insertion layer 180.

The upper electrode 170 may be formed to at least partially cover the portion of the piezoelectric layer 160 disposed on the upper portion of the cavity C. The upper electrode 170 can be configured as an input electrode or an output electrode for respectively inputting or outputting electrical signals such as radio frequency (RF) signals or the like. For example, when the lower electrode 150 is configured as an input electrode, the upper electrode 170 may be configured as an output electrode, and when the lower electrode 150 is configured as an output electrode, the upper electrode 170 may be configured as an input electrode.

As an example, the upper electrode 170 may be formed of a conductive material such as molybdenum (Mo) or an alloy of Mo. However, the upper electrode is not limited to being formed of Mo, and the upper electrode 170 may be, for example, ruthenium (Ru), tungsten (W), iridium (Ir), platinum (Pt), copper (Cu), titanium (Ti), tantalum (Ta) , Nickel (Ni), chromium (Cr) and the like, or Ru, W, Ir, Pt, Cu, Ti, Ta, Ni, or Cr alloys and other conductive materials.

The active area is, for example, an area where the lower electrode 150, the piezoelectric layer 160, and the upper electrode 170 all overlap.

As shown in FIG. 1, on the upper surface of the bulk acoustic wave resonator 100 (for example, in a top plan view), the centroid of the active area may match the center of the rectangle defining the aspect ratio of the active area, and the active area may have The shape of a polygon that is symmetric with respect to at least one axis passing through the center of the rectangle defining the aspect ratio. In this article, the description of the shape of the active region explains the overall planar shape of the active region or the planar shape of the periphery of the active region on the upper surface of the resonator.

In this example, the definition of the aspect ratio and the definition of the rectangle defining the aspect ratio will be explained in more detail.

FIG. 4 is an exemplary explanatory diagram showing the aspect ratio and centroid of an asymmetric polygon.

Referring to FIG. 4, the aspect ratio in a polygon may be defined as the ratio of the short axis to the long axis of a rectangle contacting three or more vertices of the polygon. For example, aspect ratio (AR) = h/b.

For example, in the case of an asymmetric polygon, as shown in FIG. 4, a rectangle that touches three vertices can be drawn. As shown in Figure 4, when the aspect ratio is close to 1, the center (x, y) of the rectangle contacting the polygon may almost match the centroid (x', y') of the polygon, but as the aspect ratio increases, the rectangle The center (x, y) of may increasingly not match the centroid (x', y') of the polygon.

FIG. 5 is an exemplary explanatory diagram showing a rectangle defining the aspect ratio of an asymmetric polygon.

As shown in FIG. 5, rectangles contacting three or more vertices of an asymmetric polygon may be shown as various types of rectangles depending on the rotation angle of the same polygon. Among the various types of rectangles shown in FIG. 5, the rectangle defining the aspect ratio will be defined as the rectangle having the largest aspect ratio. For example, a rectangle that contacts a polygon with a rotation angle of 0° can be defined as a rectangle that defines an aspect ratio.

According to an example, the aspect ratio may be greater than or equal to 2 and less than or equal to 10, for example. For example, as shown in FIG. 6, it can be understood that the peak insertion loss (Peak_IL) increases as the aspect ratio (AR) increases, and the parasitic noise also increases as the aspect ratio (AR) increases.

For example, as the aspect ratio (AR) increases, the resistance loss at the resonance point can be reduced. For example, it can be understood that when the aspect ratio is greater than 2, the peak insertion loss (Peak_IL) is increased to about -0.06 decibels (dB), and when the aspect ratio is greater than 3, the peak insertion loss (Peak_IL) is increased to about -0.05 decibels .

In addition, as the aspect ratio (AR) increases, the overlap of the resonant mode and the harmonic mode reflected from each side can be reduced to improve spurious noise. For example, it can be understood that when the aspect ratio is greater than 2, the parasitic noise can be less than 0.08 decibels, and when the aspect ratio is greater than 3, the parasitic noise can be less than 0.07 decibels.

As an example, when the active area has a rhombus shape and the aspect ratio (AR) of the active area is 10 or greater, the angle in the rhombus may become very narrow. That is, at least one angle between the sides having a common vertex in the rhombus may be very narrow. In this case, the overlap of harmonic modes may increase, or the resonance itself may not be driven smoothly.

2 and 3 again, the insertion layer 180 may be disposed between the lower electrode 150 and the piezoelectric layer 160. The insertion layer 180 can be made of, for example, silicon _{oxide (SiO 2} ), aluminum nitride (AlN), aluminum oxide (Al ₂ O ₃ ), silicon nitride (Si ₃ N ₄ ), manganese oxide (MgO), zirconium oxide (ZrO ₂ ) , Lead zirconate titanate (PZT), gallium arsenic (GaAs), hafnium oxide (HfO ₂ ), titanium oxide (TiO ₂ ), zinc oxide (ZnO) or the like and other dielectric materials, but it can be combined with the piezoelectric layer 160 The material is formed of different materials.

In addition, at least part of the insertion layer 180 may be disposed between the piezoelectric layer 160 and the lower electrode 150. As an example, the insertion layer 180 may have a ring shape.

The passivation layer 190 may be formed in a region except for parts of the lower electrode 150 and the upper electrode 170. The passivation layer 190 may prevent damage to the upper electrode 170 and the lower electrode 150 during the operation of the bulk acoustic wave resonator 100.

As an example, the passivation layer 190 may include silicon nitride (Si ₃ N ₄ ), silicon _{oxide (SiO 2} ), manganese oxide (MgO), zirconium oxide (ZrO ₂ ), aluminum nitride (AlN), lead zirconate titanate ( A dielectric layer of any one of PZT), gallium arsenic (GaAs), hafnium oxide (HfO ₂ ), aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), and zinc oxide (ZnO) is formed.

The metal pad 195 may be formed on the lower electrode 150 and on a portion of the upper electrode 170 where the passivation layer 190 is not formed. As an example, the metal pad 195 may be, for example, gold (Au), gold-tin (Au-Sn) alloy, copper (Cu), copper-tin (Cu-Sn) alloy, aluminum (Al), aluminum alloy, or the like. Made of materials. For example, the aluminum alloy may be an aluminum germanium (Al-Ge) alloy.

As described above, since the active region has an axisymmetric rhombus shape, the Q performance can be improved during resonance driving. In addition, since the active area has an axisymmetric shape, parasitic noise can be reduced.

FIG. 7 is a schematic plan view showing an example in which the active region of a bulk acoustic wave resonator (hereinafter referred to as a “resonator”) has an axisymmetric rhombus shape and an aspect ratio of 1. FIG. 8 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric rhombus shape and an aspect ratio of 1.5. FIG. 9 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric rhombus shape and an aspect ratio of 2.0. 10 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric rhombus shape and an aspect ratio of 2.5. FIG. 11 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric rhombus shape and an aspect ratio of 3.0. FIG. 12 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric rhombus shape and an aspect ratio of 3.5.

As shown in Figures 7 to 12, it can be seen that when the active area of the resonator has a rhombus shape on the upper surface of the resonator (for example, in a top plan view), the centroid of the rhombus and the defining rhombus/ The aspect ratio of the active area matches the center of the rectangle.

13 to 15 are schematic plan views showing a resonator according to an example, in which the active area of the resonator has a shape that is an axisymmetric rhombus.

In the following description, referring to the included angle of the rhombus is to explain the smallest included angle among the included angles of the rhombus.

The resonator (AR 1.0) shown in FIG. 13 is an example in which the angle θ of the rhombus is 90° and the aspect ratio of the rhombus is 1. In this case, the overlap area of the normal vectors on each side (OA, where O is the center of the rhombus, and A is the vertex of the rhombus) can be equal to (100% of) the total area of the rhombus.

In addition, the resonator (AR 1.7) shown in FIG. 14 is an example in which the angle θ of the rhombus is 60° and the aspect ratio of the rhombus is 1.7. In this case, the overlap area (OA) of the normal vectors on each side can be 50% of the total area of the rhombus.

In addition, the resonator (AR 3.8) shown in FIG. 15 is an example in which the angle θ of the rhombus is 26° and the aspect ratio of the rhombus is 3.8. In this case, the overlapping area of the normal vectors on each side can be 12% of the total area of the rhombus.

As shown in FIG. 16, the parasitic noise of the resonator may be the largest in the case of AR 1.0, may be smaller than that of AR 1.0 in the case of AR 1.7, and may be smallest in the case of AR 3.8.

The spurious noise changes depending on the aspect ratio in the active region having a diamond shape, because the aspect ratio affects the overlap amount of the resonance mode and the harmonic mode. For example, in a case where two opposite sides of a rhombus with an aspect ratio close to 1.0 are arranged in parallel, the resonance mode and harmonic mode reflected from each side may overlap 100%, and the parasitic noise may increase.

As the aspect ratio increases, the two opposite sides of the rhombus can be arranged in parallel, but the size of the overlap area of the normal vector on each side can be relatively reduced. In this case, the overlap of the resonance mode and the harmonic mode reflected from each side can be reduced. Therefore, in the case of an axisymmetric polygonal structure with a relatively large aspect ratio, the parasitic noise can be reduced by this principle.

For example, since the length of each side in an axisymmetric rhombus can be the same, as shown in FIG. 17, it can be seen that the overlap area ratio of the normal vector of each side can depend on the value of the angle θ of the rhombus. Variety. In addition, in order to reduce the parasitic noise, the angle θ of the rhombus can be 30° or less than 30°.

When the angle θ of the rhombus is 30°, the overlap area ratio of the normal vectors of each side can be 13.4%, and in this case, the aspect ratio of the axisymmetric rhombus can be 3.7.

Table 1 below shows exemplary performance characteristics of the resonators of FIGS. 13 to 15.

Table 1 AR Angle (°) fs (Gigahertz) fp (Gigahertz) kt ² [%] IL[dB] Attenuation [dB] 1.0 90 4.8630 5.1320 12.28 -0.073 -31.9 1.7 60 4.8630 5.1320 12.28 -0.062 -31.9 3.8 26 4.8620 5.1270 12.12 -0.049 -29.7

In the case where the resonator shown in FIG. 13 has an aspect ratio of 3.8, in the resonator shown in FIGS. 13 to 15, it can be understood that the insertion loss performance at the resonance point can be significantly improved as shown in Table 1 above. improve. This indicates that the resistance loss at the resonance point is relatively small. In this example, “IL” refers to the maximum value of the magnitude S21 at the resonance point, and “attenuation (Attn.)” refers to the minimum value of the magnitude S21 at the anti-resonance point.

FIG. 18 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric hexagonal shape and an aspect ratio of 1. FIG. 19 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric hexagonal shape and an aspect ratio of 1.5. 20 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric hexagonal shape and an aspect ratio of 2.0. 21 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric hexagonal shape and an aspect ratio of 2.5. 22 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric hexagonal shape and an aspect ratio of 3.0. FIG. 23 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric hexagonal shape and an aspect ratio of 3.5.

As shown in FIGS. 18 to 23, it can be seen that when the active region of the resonator has a hexagonal shape on the upper surface of the resonator (for example, in a top plan view), the centroid of the hexagon Matches the center of the rectangle defining the aspect ratio of the hexagon/active area.

As described above, even when the axisymmetric hexagon has a relatively high aspect ratio, symmetry can be maintained to improve Q performance during resonance driving. In addition, in a hexagon with a relatively high aspect ratio, since design variables may increase due to the increase of the upper and lower sides of the hexagon, the degree of design freedom may increase to further reduce the resonance point resistance. In this case, the upper and lower sides of the hexagon can be parallel to each other, but when a hexagon with a relatively high aspect ratio is formed, the distance between the upper and lower sides of the hexagon can be longer , In order to reduce the influence between the upper side and the lower side, thereby suppressing the deterioration of the parasitic noise performance.

FIG. 24 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric octagonal shape and an aspect ratio of 1. FIG. 25 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric octagonal shape and an aspect ratio of 1.5. FIG. 26 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric octagonal shape and an aspect ratio of 2.0. FIG. 27 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric octagonal shape and an aspect ratio of 2.5. FIG. 28 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric octagonal shape and an aspect ratio of 3. FIG. FIG. 29 is a schematic plan view showing an example in which the active region of the resonator has an axisymmetric octagonal shape and an aspect ratio of 3.5.

As shown in FIGS. 24 to 29, it can be seen that when the active area of the resonator has an octagonal shape on the upper surface of the resonator (for example, in a top plan view), the centroid of the octagon Matches the center of the rectangle defining the aspect ratio of the octagon/active area.

As described above, even when the axisymmetric octagon has a relatively high aspect ratio, symmetry can be maintained to improve Q performance during resonance driving. In addition, in the high aspect ratio octagon, it is helpful to improve the spurious noise performance, because the overlap area of the normal vector on each side (for example, the upper side and the lower side of the octagon) can be further reduced.

FIG. 30 is a schematic plan view showing an example in which the active region of the resonator has a shape of an asymmetric polygon and an aspect ratio of 2.4. FIG. 31 is a schematic plan view showing an example in which the active region of the resonator has an asymmetric polygonal shape and an aspect ratio of 3.8. FIG. 32 is a schematic plan view showing an example in which the active region of the resonator has an asymmetric polygonal shape and an aspect ratio of 5.1. FIG. 33 is a schematic plan view showing an example in which the active region of the resonator has a shape of an asymmetric polygon and an aspect ratio of 12.4.

An example of the impedance value that changes depending on the frequency of the resonator shown in FIGS. 30 to 33 can be seen in the graph shown in FIG. 34. Examples of the spurious noise of the resonator shown in FIGS. 30 to 33 can be seen in the graph shown in FIG. 35. As shown in FIG. 35, it can be understood that in the resonator having an aspect ratio of 10 or less as shown in FIG. 33, the spurious noise is greatly deteriorated.

As shown in Table 2 below, it can be understood that as the aspect ratio increases, the resistance loss at the resonance point can be reduced to improve the insertion loss, but the kt ² performance and attenuation performance may be degraded.

Table 2 AR Angle (°) fs (Gigahertz) fp (Gigahertz) kt ² [%] IL[dB] Attenuation [dB] 2.4 13 4.8630 5.1310 12.24 -0.057 -30.6 3.8 13 4.8620 5.1250 12.04 -0.052 -28.8 5.1 9.5 4.8620 5.1210 11.87 -0.045 -27.2 12.4 2.7 4.8590 5.1100 11.55 -0.037 -24.4

36 is a schematic plan view showing an example in which the active region of the resonator has a shape of an axisymmetric polygon and an aspect ratio of 2.4. FIG. 37 is a schematic plan view showing an example in which the active region of the resonator has a shape of an axisymmetric polygon and an aspect ratio of 3.8. FIG. 38 is a schematic plan view showing an example in which the active region of the resonator has a shape of an axisymmetric polygon and an aspect ratio of 5.1. FIG. 39 is a schematic plan view showing an example in which the active region of the resonator has a shape of an axisymmetric polygon and an aspect ratio of 12.4.

Exemplary impedance values that vary depending on the frequency of the resonator shown in FIGS. 36 to 39 can be seen in the graph shown in FIG. 40. The exemplary spurious noise of the resonator shown in FIGS. 36 to 39 can be seen in the graph shown in FIG. 41. As shown in FIG. 41, it can be understood that in the resonator having an aspect ratio of 10 or less as shown in FIG. 39, the spurious noise is greatly deteriorated.

table 3 AR Angle (°) fs (Gigahertz) fp (Gigahertz) kt ² [%] IL[dB] Attenuation [dB] 2.4 26 4.8630 5.1320 12.28 -0.057 -33.8 3.8 26 4.8620 5.1270 12.12 -0.049 -29.7 5.1 19 4.8620 5.1230 11.96 -0.045 -28.5 12.4 5.5 4.8590 5.1110 11.59 -0.036 -24.7

As shown in Table 3, it can be understood that the insertion loss (IL), kt ² performance, and parasitic noise performance of the axisymmetric polygon resonator are equal to or higher than the insertion loss (IL), kt of the asymmetric polygon resonator in Table 2. ² Performance and parasitic noise performance. For example, as shown in Table 3, it can be understood that compared to the asymmetric polygonal resonator in Table 2, the attenuation performance of the axisymmetric polygonal resonator is improved.

The improved performance can be attributed to the improvement in Q performance caused by the smoother resonance drive of the axisymmetric polygonal resonator compared to the asymmetric polygonal resonator with a relatively high aspect ratio structure. In addition, as shown in Table 3, compared to the spurious noise performance of the asymmetric polygonal resonator, when the aspect ratio of the axisymmetric polygonal resonator is 12.4, the spurious noise performance can be improved.

42 is a schematic plan view showing an example in which the active region of the resonator has a shape of an axisymmetric polygon and an aspect ratio of 3.8. FIG. 43 is a schematic plan view showing an example in which the active region of the resonator has a shape of an axisymmetric polygon and an aspect ratio of 4.8. 44 is a schematic plan view showing an example in which the active region of the resonator has a shape of an axisymmetric polygon and an aspect ratio of 5.1. FIG. 45 is a schematic plan view showing an example in which the active region of the resonator has a shape of an axisymmetric polygon and an aspect ratio of 5.6.

The resonator shown in FIG. 42 is an example in which the included angle θ is 26° and the length of one side is 130 micrometers (μm), and the resonator shown in FIG. 43 is an example in which the included angle θ is 13° and the length of one side is 130 Examples of micrometers.

In addition, the resonator shown in FIG. 44 is an example in which the included angle θ is 19° and the length of one side is 150 microns, and the resonator shown in FIG. 45 is an example in which the included angle θ is 15° and the length of one side is 150 microns. Instance.

Exemplary impedance values that vary depending on the frequency of the resonator shown in FIGS. 42 to 45 can be seen in the graph shown in FIG. 46. The exemplary spurious noise of the resonator shown in FIGS. 42 to 45 can be seen in the graph shown in FIG. 47.

Table 4 below shows exemplary performance characteristics of the resonators of FIGS. 42 to 45.

Table 4 AR Angle (°) fs (Gigahertz) fp (Gigahertz) kt ² [%] IL[dB] Attenuation [dB] 3.8 26 4.8620 5.1270 12.12 -0.049 -29.7 4.8 13 4.8620 5.1260 12.08 -0.042 -30.5 5.1 19 4.8620 5.1230 11.96 -0.045 -28.5 5.6 15 4.8610 5.1230 12.00 -0.043 -30.5

Referring to Table 4, when comparing the performance of the resonator shown in FIG. 42 with the performance of the resonator shown in FIG. 43, it can be understood that the resonator shown in FIG. 43 has improved insertion loss (IL) performance and attenuation efficacy. In addition, when comparing the performance of the resonator shown in FIG. 44 with the performance of the resonator shown in FIG. 45, it can be understood that the resonator shown in FIG. 45 has improved insertion loss (IL) performance and attenuation performance.

FIG. 48 is an exemplary explanatory diagram showing a resonator in which the active region of the resonator has a shape that is an X-axis symmetric polygon, and the centroid of the active region and the center of the rectangle defining the aspect ratio are spaced apart from each other in the Y-axis direction . FIG. 49 is a graph showing that the attenuation efficiency according to an example varies depending on the separation ratio of the centroid of the active region.

As shown in FIG. 48, the centroid of the active area on the upper surface of the resonator (for example, in a top plan view) does not match the center of the rectangle defining the aspect ratio of the active area. It can be seen that the X-axis coordinate value of the centroid of the active area can match the X-axis coordinate value of the center of the rectangle that defines the aspect ratio of the active area, and the Y-axis coordinate value of the centroid of the active area can be the same as that of the active area. The Y-axis coordinate value of the center of the rectangle of the aspect ratio does not match.

In addition, according to the embodiment, the bulk acoustic wave resonator may satisfy y'/h<0.067, where y'is the separation distance between the centroid of the active region and the center of the rectangle in the Y-axis direction, and h is in the Y-axis direction The length of the upper active area. For example, as shown in FIG. 49, it can be understood that when the value of y'/h is greater than 0.067, the attenuation performance may be rapidly degraded. In addition, it can be understood that when the value of y'/h is less than 0.067, even in the case where the symmetry of the active region is slightly wrong, the attenuation performance may not be significantly degraded.

Even when the active area has a relatively high aspect ratio, the resistance loss and parasitic noise performance at the resonance point can be improved, and the Q performance can also be improved.

Although the content of this disclosure includes specific examples, it will be obvious after understanding the disclosure content of this application that without departing from the spirit and scope of the scope of the patent application and its equivalent scope, the forms and details of these examples can be made. Various changes. The examples described herein are only to be regarded as illustrative and not for limiting purposes. The description of the feature or aspect in each example should be regarded as applicable to similar features or aspects in other examples. If the technology is executed in a different order, and/or if the components in the system, architecture, device, or circuit are combined in different ways and/or replaced or supplemented by other components or their equivalents, it can be achieved Appropriate results. In addition, the corresponding embodiments may be combined with each other. For example, the pressing members disclosed in the above embodiments can be used in combination with each other in a force sensing device. Therefore, the scope of the disclosure is not defined by the detailed description, but by the scope of the patent application and its equivalent scope, and all changes within the scope of the patent application and its equivalent scope shall be interpreted as being included in In the content of this disclosure.

100: Bulk Acoustic Wave Resonator 110: substrate 112: Insulation layer 120: Sacrifice Layer 130: Etching prevention part 150: lower electrode 160: Piezo layer 162: Piezoelectric part 164: Curved part 164a: Inclined part 164b: Extension 170: Upper electrode 180: Insert layer 190: passivation layer 195: Metal pad C: cavity E: Extended section h: length I-I’, II-II’: Line L: Inclined surface S: Plane section S21: Value (x, y): center (x’, y’): Xingxin θ: Tilt angle/Included angle

FIG. 1 is a schematic plan view showing a bulk acoustic wave resonator according to the embodiment. Fig. 2 is a cross-sectional view taken along the line I-I' shown in Fig. 1. Fig. 3 is a cross-sectional view taken along the line II-II' shown in Fig. 1. FIG. 4 is an exemplary explanatory diagram showing the aspect ratio and centroid of an asymmetric polygon. FIG. 5 is an exemplary explanatory diagram showing a rectangle defining the aspect ratio of an asymmetric polygon. FIG. 6 is a graph showing how the performance of a bulk acoustic wave resonator according to an example varies depending on the aspect ratio. FIG. 7 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric rhombus shape and an aspect ratio of 1. FIG. FIG. 8 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric rhombus shape and an aspect ratio of 1.5. 9 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric rhombus shape and an aspect ratio of 2.0. 10 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric rhombus shape and an aspect ratio of 2.5. FIG. 11 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric rhombus shape and an aspect ratio of 3.0. FIG. 12 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric rhombus shape and an aspect ratio of 3.5. 13 to 15 are schematic plan views showing a bulk acoustic wave resonator according to an example, in which the active area of the resonator has a shape that is an axisymmetric rhombus. FIG. 16 is a graph of frequency-dependent variation of S21 according to an example, which shows spurious noise of the bulk acoustic wave resonator of FIGS. 13 to 15. FIG. 17 is a graph showing the variation of the overlap area ratio of the normal vector of each side according to an example depending on the included angle between the axisymmetric rhombuses. FIG. 18 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric hexagonal shape and an aspect ratio of 1. FIG. 19 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric hexagonal shape and an aspect ratio of 1.5. 20 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric hexagonal shape and an aspect ratio of 2.0. 21 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric hexagonal shape and an aspect ratio of 2.5. 22 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric hexagonal shape and an aspect ratio of 3.0. FIG. 23 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric hexagonal shape and an aspect ratio of 3.5. FIG. 24 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric octagonal shape and an aspect ratio of 1. FIG. 25 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric octagonal shape and an aspect ratio of 1.5. FIG. 26 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric octagonal shape and an aspect ratio of 2.0. 27 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric octagonal shape and an aspect ratio of 2.5. FIG. 28 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric octagonal shape and an aspect ratio of 3. FIG. FIG. 29 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an axisymmetric octagonal shape and an aspect ratio of 3.5. FIG. 30 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an asymmetric polygonal shape and an aspect ratio of 2.4. FIG. 31 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an asymmetric polygonal shape and an aspect ratio of 3.8. 32 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an asymmetric polygonal shape and an aspect ratio of 5.1. FIG. 33 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has an asymmetric polygonal shape and an aspect ratio of 12.4. FIG. 34 is a graph showing that the impedance value according to an example changes depending on the frequency of the bulk acoustic wave resonator shown in FIG. 30 to FIG. 33. FIG. 35 is a graph of the frequency-dependent variation of S21 according to an example, which shows the spurious noise of the bulk acoustic wave resonator shown in FIG. 30 to FIG. 33. 36 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has a shape of an axisymmetric polygon and an aspect ratio of 2.4. FIG. 37 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has a shape of an axisymmetric polygon and an aspect ratio of 3.8. FIG. 38 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has a shape of an axisymmetric polygon and an aspect ratio of 5.1. FIG. 39 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has a shape of an axisymmetric polygon and an aspect ratio of 12.4. FIG. 40 is a graph showing that the impedance value according to an example changes depending on the frequency of the bulk acoustic wave resonator shown in FIG. 36 to FIG. 39. FIG. 41 is a graph of frequency-dependent variation of S21 according to an example, which shows the spurious noise of the bulk acoustic wave resonator shown in FIG. 36 to FIG. 39. 42 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has a shape of an axisymmetric polygon and an aspect ratio of 3.8. FIG. 43 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has a shape of an axisymmetric polygon and an aspect ratio of 4.8. 44 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has a shape of an axisymmetric polygon and an aspect ratio of 5.1. FIG. 45 is a schematic plan view showing an example in which the active region of the bulk acoustic wave resonator has a shape of an axisymmetric polygon and an aspect ratio of 5.6. FIG. 46 is a graph showing that the impedance value according to an example changes depending on the frequency of the bulk acoustic wave resonator shown in FIGS. 42 to 45. FIG. 47 is a graph of S21 varying with frequency according to an example, which shows the spurious noise of the bulk acoustic wave resonator shown in FIG. 42 to FIG. 45. 48 is an exemplary explanatory diagram showing a bulk acoustic wave resonator, in which the active area of the bulk acoustic wave resonator has an X-axis symmetrical polygon, and the centroid of the active area and the center of the rectangle defining the aspect ratio are spaced apart from each other in the Y-axis direction open. FIG. 49 is a graph showing that the attenuation efficiency according to an example changes depending on the separation ratio of the centroid of the active region. Throughout the drawings and detailed description, the same reference numbers refer to the same elements. The drawings may not be drawn to scale, and for clarity, illustration, and convenience, the relative sizes, proportions, and drawings of the elements in the drawings may be exaggerated.

100: Bulk Acoustic Wave Resonator

190: passivation layer

195: Metal pad

I-I’, II-II’: Line

Claims (22)

A bulk acoustic wave resonator, including: Substrate The lower electrode is arranged on the substrate; A piezoelectric layer at least partially covering the lower electrode; and The upper electrode at least partially covers the piezoelectric layer, Wherein, on the surface of the bulk acoustic wave resonator, the centroid of the active area where the lower electrode, the piezoelectric layer, and the upper electrode all overlap each other and the aspect ratio ( The aspect ratio) is aligned with the center of the rectangle, Wherein the active area has a polygonal shape, the polygon is symmetrical with respect to at least one axis passing through the center of the rectangle defining the aspect ratio, and The aspect ratio is greater than or equal to 2 and less than or equal to 10. The bulk acoustic wave resonator according to claim 1, wherein the rectangle defining the aspect ratio is a rectangle having the largest aspect ratio among rectangles contacting three or more vertices of the polygon. The bulk acoustic wave resonator according to claim 1, wherein the polygon is a polygon having N angles, where N is an even number greater than or equal to 4. The bulk acoustic resonator according to claim 1, further comprising a film layer forming a cavity together with the substrate. The bulk acoustic wave resonator according to claim 4, further comprising an etching prevention part arranged to surround the cavity. The bulk acoustic wave resonator according to claim 5, further including a sacrificial layer provided outside the etching prevention portion. The bulk acoustic resonator according to claim 1, further comprising an insertion layer at least partially provided between the lower electrode and the piezoelectric layer. The bulk acoustic resonator according to claim 1, further including a passivation layer provided to expose a portion of the lower electrode and a portion of the upper electrode. The bulk acoustic resonator according to claim 8, further comprising a metal pad contacting the exposed part of the lower electrode and the exposed part of the upper electrode. A bulk acoustic wave resonator, including: Substrate The lower electrode is arranged on the substrate; A piezoelectric layer at least partially covering the lower electrode; and The upper electrode at least partially covers the piezoelectric layer, The centroid of the active area where the lower electrode, the piezoelectric layer, and the upper electrode all overlap each other matches the first axis coordinate value of the center of the rectangle defining the aspect ratio of the active area, and the active area The centroid of the area does not match the second axis coordinate value of the center of the rectangle that defines the aspect ratio of the active area, and the first axis coordinate value is relative to the second axis coordinate value that defines the aspect ratio The coordinate value of the first axis of the rectangle, and the second axis coordinate value is relative to the coordinate value of the second axis of the rectangle defining the aspect ratio, and Wherein the bulk acoustic wave resonator satisfies y'/h<0.067, and y'is the separation distance between the centroid of the active region and the center of the rectangle in the direction of the second axis, And h is the length of the active area in the direction of the second axis. The bulk acoustic resonator according to claim 10, wherein the active area is symmetrical with respect to the first axis. The bulk acoustic wave resonator according to claim 10, wherein the rectangle defining the aspect ratio is a rectangle having the largest aspect ratio among rectangles contacting three or more vertices of the peripheral shape of the active region. The bulk acoustic resonator according to claim 10, further comprising an insertion layer partially provided between the lower electrode and the piezoelectric layer. The bulk acoustic wave resonator according to claim 13, wherein the insertion layer has a ring shape. A bulk acoustic wave resonator, including: The lower electrode is arranged on the substrate; A piezoelectric layer disposed on the lower electrode; and The upper electrode is arranged on the piezoelectric layer, Wherein the perimeter of the active region where the lower electrode, the piezoelectric layer, and the upper electrode all overlap each other has a polygonal shape relative to at least the center of the rectangle passing through the aspect ratio of the polygon An axis symmetry, Wherein the centroid of the polygon is aligned with the center of the rectangle defining the aspect ratio, and The aspect ratio is greater than or equal to 2 and less than or equal to 10. The bulk acoustic resonator according to claim 15, wherein the at least one shaft includes only one shaft. The bulk acoustic wave resonator according to claim 15, wherein the polygon is any one of a rhombus, a hexagon, and an octagon. The bulk acoustic wave resonator according to claim 15, wherein the aspect ratio is greater than or equal to 2.4 and less than or equal to 5.6. The bulk acoustic wave resonator according to claim 15, wherein the rectangle defining the aspect ratio is a rectangle having the largest aspect ratio among rectangles contacting three or more vertices of the polygon. A bulk acoustic wave resonator, including: The lower electrode is arranged on the substrate; A piezoelectric layer disposed on the lower electrode; and The upper electrode is arranged on the piezoelectric layer, Wherein the active area where the lower electrode, the piezoelectric layer, and the upper electrode all overlap each other has a polygonal shape, Wherein the centroid of the polygon matches the first axis coordinate value of the center of the rectangle defining the aspect ratio of the polygon, and the centroid of the active area matches the aspect ratio of the polygon. The second axis coordinate value of the center of the rectangle does not match, the first axis coordinate value is relative to the coordinate value of the first axis of the rectangle that defines the aspect ratio, and the second axis coordinate value is Relative to the coordinate value of the second axis of the rectangle that defines the aspect ratio, and Wherein the bulk acoustic wave resonator satisfies y'/h<0.067, and y'is the separation distance between the centroid of the active region and the center of the rectangle in the direction of the second axis, And h is the length of the active area in the direction of the second axis. The bulk acoustic wave resonator according to claim 20, wherein the active area is symmetrical with respect to the first axis. The bulk acoustic wave resonator according to claim 20, wherein the polygon is a hexagon.

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