KR102703814B1 - Acoustic resonator and method of manufacturing thereof - Google Patents

Abstract

An acoustic resonator according to an embodiment of the present invention may include a substrate, a vibration-active region formed by sequentially stacking a lower electrode, a piezoelectric layer, and an upper electrode on the substrate, and a horizontal resonance suppressor disposed within the piezoelectric layer but having different properties from the piezoelectric layer.

Description

{ACOUSTIC RESONATOR AND METHOD OF MANUFACTURING THEREOF}

The present invention relates to an acoustic resonator and a method for manufacturing the same.

In line with the trend toward miniaturization of wireless communication devices, miniaturization of high-frequency component technology is actively demanded. One example is a filter in the form of a bulk acoustic wave (BAW) that utilizes semiconductor thin-film wafer manufacturing technology.

A bulk acoustic resonator (BAW) is a thin-film element implemented as a filter that induces resonance by depositing a piezoelectric dielectric material on a semiconductor substrate, a silicon wafer, and utilizing its piezoelectric properties.

Applications of bulk acoustic resonators include small and lightweight filters, oscillators, resonant elements, and acoustic resonant mass sensors for mobile communication devices, chemical and bio-devices, etc.

Meanwhile, research is being conducted on various structural shapes and functions to improve the characteristics and performance of bulk acoustic resonators, and various studies are also being conducted on manufacturing methods accordingly.

Korean Patent No. 0906679

An object of the present invention is to provide an acoustic resonator capable of improving performance and a method for manufacturing the same.

An acoustic resonator according to an embodiment of the present invention may include a substrate, a vibration-active region formed by sequentially stacking a lower electrode, a piezoelectric layer, and an upper electrode on the substrate, and a horizontal resonance suppressor disposed within the piezoelectric layer but having different properties from the piezoelectric layer.

An acoustic resonator according to an embodiment of the present invention may include a substrate, a lower electrode disposed on the substrate, a piezoelectric layer laminated on the lower electrode, an upper electrode laminated on the piezoelectric layer, and a horizontal resonance suppressor disposed within the piezoelectric layer but having different properties from the piezoelectric layer.

In addition, a method for manufacturing an acoustic resonator according to an embodiment of the present invention may include a step of sequentially stacking a lower electrode and a piezoelectric layer on a substrate, a step of partially injecting ions into the piezoelectric layer to form a horizontal resonance suppression portion within the piezoelectric layer, and a step of stacking an upper electrode on the piezoelectric layer to complete a vibration active region.

The acoustic resonator according to the present invention and its manufacturing method can minimize noise and deterioration of resonator performance caused by horizontal wave resonance by suppressing spurious resonance caused by horizontal waves through a horizontal resonance suppression unit.

FIG. 1 is a cross-sectional view schematically illustrating an acoustic resonator according to an embodiment of the present invention.
Fig. 2 is an enlarged cross-sectional view of the resonance section of Fig. 1.
Figure 3 is a graph comparing the insertion loss of the acoustic resonator illustrated in Figure 2 and a conventional acoustic resonator.
FIG. 4 is a cross-sectional view illustrating a resonating portion of an acoustic resonator according to another embodiment of the present invention.
Figure 5 is a graph comparing the insertion loss of the acoustic resonator illustrated in Figure 4 and a conventional acoustic resonator.
FIG. 6 is a cross-sectional view illustrating a resonating portion of an acoustic resonator according to another embodiment of the present invention.
Figure 7 is a graph comparing the insertion loss of the acoustic resonator illustrated in Figure 6 and a conventional acoustic resonator.
FIG. 8 is a cross-sectional view illustrating a resonating portion of an acoustic resonator according to another embodiment of the present invention.
FIGS. 9 to 11 are drawings for explaining a method for manufacturing the acoustic resonator illustrated in FIGS. 1 and 2.
Figures 12 and 13 are drawings for explaining a method for manufacturing the acoustic resonator illustrated in Figure 8.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. However, the spirit of the present invention is not limited to the presented embodiments, and those skilled in the art who understand the spirit of the present invention will be able to easily propose other regressive inventions or other embodiments included within the scope of the spirit of the present invention by adding, changing, or deleting other components within the scope of the same spirit, but this will also be considered to be included within the scope of the spirit of the present invention.

In addition, throughout the specification, when a component is said to be 'connected' to another component, it means not only that these components are 'directly connected', but also that they are 'indirectly connected' with other components in between. Also, when a component is said to 'include', it means that other components may be included, rather than excluding other components, unless otherwise specifically stated.

FIG. 1 is a cross-sectional view schematically illustrating an acoustic resonator according to an embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view illustrating an enlarged portion of the resonating portion of FIG. 1.

Referring to FIGS. 1 and 2, an acoustic resonator according to the present embodiment may include a substrate (110) and a resonant portion (120).

An air gap (130) is formed between the substrate (110) and the resonant portion (120), and the resonant portion (120) is formed on the membrane layer (150) and is separated from the substrate (110) through the air gap (130).

The substrate (110) may be formed of a silicon substrate or a SOI (Silicon On Insulator) type substrate. However, it is not limited thereto, and various substrates such as a glass substrate may be used.

The resonating portion (120) includes a lower electrode (121), a piezoelectric layer (123), and an upper electrode (125). The resonating portion (120) can be formed by sequentially stacking the lower electrode (121), the piezoelectric layer (123), and the upper electrode (125) from below. Accordingly, the piezoelectric layer (123) is arranged between the lower electrode (121) and the upper electrode (125).

Since the resonant portion (120) is formed on the membrane layer (150), ultimately, the membrane layer (150), lower electrode (121), piezoelectric layer (123), and upper electrode (125) are sequentially laminated on the upper portion of the substrate (110).

The resonant portion (120) can generate a resonant frequency and an anti-resonant frequency by resonating the piezoelectric layer (123) according to signals applied to the lower electrode (121) and the upper electrode (125).

The lower electrode (121) and the upper electrode (125) can be formed using a metal such as gold, molybdenum, ruthenium, aluminum, platinum, titanium, tungsten, palladium, chromium, nickel, etc. as the main material, and in the present embodiment, both the lower electrode (121) and the upper electrode (125) are formed using molybdenum (Mo).

The resonating part (120) uses the acoustic wave of the piezoelectric layer (123). For example, when a signal is applied to the lower electrode (121) and the upper electrode (125), mechanical vibration occurs in the thickness direction of the piezoelectric layer (123), thereby generating an acoustic wave.

Here, zinc oxide (ZnO), aluminum nitride (AlN), quartz, etc. can be used as the material of the piezoelectric layer (123).

The resonance phenomenon of the piezoelectric layer (123) occurs when half of the applied signal wavelength matches the thickness of the piezoelectric layer (123). When the resonance phenomenon occurs, the electrical impedance changes rapidly, so the acoustic resonator according to the present embodiment can be used as a filter capable of selecting a frequency.

The resonance unit (120) may be spaced apart from the substrate (110) through an air gap (130) to improve the quality factor.

The reflection characteristics of acoustic waves generated in the resonating portion (120) can be improved through the air gap (130). Since the air gap (130) is an empty space and has an impedance close to infinity, the acoustic waves are not lost to the air gap (130) and can remain within the resonating portion (120).

A frame (170) may be placed on top of the upper electrode (125).

The frame (170) is formed on the upper electrode (125) in a ring shape along the outline of the resonant portion (120).

The resonating portion (120) generates actual vibrations in a vibration-active area (A in FIG. 2) whose overall shape is defined by the inner wall of the frame (170). Here, the vibration-active area (A) is defined as an area located within the frame (170) when the resonating portion (120) is viewed from the direction A in FIG. 2.

The frame (170) reflects horizontal elastic waves generated in the vibration active region (A) and directed outside the resonating portion (120) toward the center of the resonating portion (120) to prevent energy loss of the elastic waves. Accordingly, the acoustic resonator according to the present embodiment can secure a high Q-factor, kt2.

A high Q-factor can improve the blocking characteristics of other frequency bands when implementing a filter or duplexer, and a high kt2 can secure bandwidth, thereby increasing the amount of data transmitted and received and the speed.

The vibration active area (A) can be formed in a plane of a polygonal or elliptical shape, and correspondingly, the frame (170) can also be formed in a ring shape of a polygonal or elliptical shape.

The frame (170) is composed of a piezoelectric material, a dielectric, or a metal. For example, the frame (170) may be formed of a composite material having one or more of aluminum nitride (AlN), lead zirconate titanate (PZT), silicon oxide (SiO ₂ ), titanium oxide (TiO ₂ ), ruthenium (Ru), molybdenum (Mo), gold (Au), titanium (Ti), copper (Cu), tungsten (W), and aluminum (Al) as a main component.

The frame (170) according to the present embodiment can be formed by forming a frame layer on the upper electrode (125) through sputtering or deposition, and then removing unnecessary portions from the frame layer through an etching or lift-off process.

The frame (170) may be formed of the same material as the upper electrode (125), and may be additionally formed during the process of forming the upper electrode (125).

In addition, the acoustic resonator according to the present embodiment has a horizontal resonance suppression unit (140) placed within the piezoelectric layer (123) to suppress spurious vibrations, which are unnecessary vibrations.

The horizontal resonance suppression unit (140) can be formed by injecting impurities into the piezoelectric layer (123). The horizontal resonance suppression unit (140) changes the material properties (stiffness, piezoelectric constant, etc.) of a desired region within the piezoelectric layer (123). Accordingly, the horizontal wave generated from the resonance unit (100) can be effectively restricted, thereby minimizing the occurrence of noise (e.g., horizontal wave noise) due to horizontal wave resonance.

The horizontal resonance suppression unit (140) can be formed in various depths and shapes by varying the type of ion injected, the energy applied during ion injection, the dose, the heat treatment temperature, and the time.

When the piezoelectric layer (123) is formed of AlN, the horizontal resonance suppression part (140) can be formed by injecting ions such as Sc, Mg, Nb, Zr, and Hf to replace a portion of the piezoelectric layer (123). In this case, the injected ions replace Al of the piezoelectric layer (123) and change the physical properties of the corresponding portion. Accordingly, the piezoelectric performance of the horizontal resonance suppression part (140) can be increased compared to other portions where ions are not injected.

In addition, the horizontal resonance suppression portion (140) may be formed by intentionally destroying the lattice structure of the piezoelectric layer (123) with ions such as Ar, Oxygen, B, P, and N. In this case, the injected ions destroy the connection structure between Al and N, thereby changing the physical properties of the corresponding region, and thus the piezoelectric performance of the horizontal resonance suppression portion (140) may be degraded compared to other parts where the ions are not injected.

The horizontal resonance suppression unit (140) is formed within the piezoelectric layer (123) and is partially or entirely positioned within the vibration active area (A). The horizontal resonance suppression unit (140) of the present embodiment is divided into a first area (141) positioned within the vibration active area (A), and a second area (142) positioned at the lower portion of the frame (170) and on the outer side of the frame (170) outside the vibration active area (A).

The first region (141) is arranged within the vibration active region (A) along the boundary of the vibration active region (A) with a constant width (e.g., 5 μm). Here, the boundary of the vibration active region (A) can be defined by the boundary between the upper electrode (125) and the frame (170).

Meanwhile, in the present embodiment, the first region (141) is formed continuously along the border of the vibration active region (A). However, this is not limited to this, and it is also possible to form the first region (141) partially or discontinuously as needed.

The upper surface area of the first region (141) disposed within the vibration active region (A) can be formed to be 50% or less of the total upper surface area of the vibration active region (A).

In order to change the properties of the piezoelectric layer (123) through ion injection, the horizontal resonance suppression member (140) must be formed with a thickness of 0.05 um or more. Therefore, the minimum thickness of the horizontal resonance suppression member (140) according to the present embodiment can be set to 0.05 um. In addition, the maximum thickness of the horizontal resonance suppression member (140) can be formed to be the same as the thickness of the piezoelectric layer (123).

For example, in this embodiment, the thickness of the horizontal resonance suppression member (140) is greater than 0.05 um and formed to be less than half the thickness of the piezoelectric layer (123). The configuration of the present invention is not limited thereto and various modifications are possible.

The resonant portion (120) may further include a protective layer (127). The protective layer (127) is formed on the second electrode (125), the frame (170), the lower electrode (121), the upper electrode (125), and the piezoelectric layer (123) to prevent the components from being exposed to the external environment.

Meanwhile, the lower electrode (121) and the upper electrode (125) are partially exposed to the outside of the protective layer (127), and a first connection electrode (160a) and a second connection electrode (160b) are formed in the exposed portions, respectively.

The first connection electrode (160a) and the second connection electrode (160b) may be provided to check the acoustic resonator and filter characteristics and perform necessary frequency trimming, but are not limited thereto.

The acoustic resonator according to the present embodiment, configured as described above, suppresses spurious resonance caused by horizontal waves through a horizontal resonance suppression unit (140), thereby minimizing noise caused by horizontal wave resonance and deterioration of resonator performance.

Unwanted resonance is caused by horizontal waves (or transverse mode standing waves) generated in the resonant section (120), which distort or deteriorate the resonance performance.

Therefore, in order to minimize unwanted resonance, the horizontal resonance suppression unit (140) according to the present embodiment is formed along the inner wall of the frame (170) to change the material properties of the boundary portion where the vibration active area (A) and the frame (170) meet. Accordingly, the resonance unit (120) according to the present embodiment is formed with different vertical amplitudes in the central portion where the horizontal resonance suppression unit (140) is not formed and in the edge portion of the vibration active area (A) where the horizontal resonance suppression unit (140) is formed.

Due to this, the above-mentioned center and horizontal resonance suppression member (140) have different wave numbers in the transverse direction at the resonance frequency, so that the overall vibration form changes. For example, as the material properties of the horizontal resonance suppression member (140) change, the vertical amplitude changes more rapidly in the horizontal resonance suppression member (140). Accordingly, the vertical amplitude change amount according to the horizontal distance between the vibration active region (A) and the horizontal resonance suppression member (140) changes, so that the occurrence of horizontal resonance is suppressed at a frequency lower than the resonance frequency.

In addition, the acoustic resonator according to the present embodiment increases the Q factor of the resonator (100) by suppressing vibrations generated in the vibration-active area (A) from escaping to the outside of the vibrating section by using the frame (170), and suppresses resonance of horizontal vibration by using the horizontal resonance suppression section (140) formed along the edge of the vibration-active area (A). Therefore, the Q, kt ² of the resonator (100) can be increased, and at the same time, horizontal wave noise can be minimized.

In addition, in the conventional case, in order to minimize noise due to horizontal wave resonance, the resonating portion is formed in an elliptical shape or an irregular shape. However, in the acoustic resonator according to the present embodiment, noise due to horizontal wave resonance can be effectively suppressed through the horizontal resonance suppression portion (140), so that the resonating portion (120) can be formed into a square shape. Accordingly, when a plurality of resonating portions (120) are arranged on a substrate, the resonating portions (120) can be arranged efficiently, and the spacing between the resonating portions can also be minimized. Accordingly, the size of the module including the resonating portion (120) can be minimized, and the mounting area can be reduced.

Fig. 3 is a graph comparing the insertion loss of the acoustic resonator illustrated in Fig. 2 with that of a conventional acoustic resonator. Here, the acoustic resonator illustrated in Fig. 2 forms a piezoelectric layer (123) with AlN, and N ions are injected into the piezoelectric layer (123) to form a horizontal resonance suppression portion (140).

Referring to Fig. 3, the conventional acoustic resonator exhibits significant noise due to horizontal wave resonance in a frequency band of 2.04 GHz or less. On the other hand, it can be seen that the acoustic resonator according to the present embodiment exhibits significantly reduced noise due to horizontal wave resonance compared to the conventional acoustic resonator in the same frequency band.

Since the acoustic resonator according to the present embodiment configured as described above uses an ion injection method, the horizontal resonance suppression member (140) can be placed in a desired region, with a desired shape, and with desired physical properties within the piezoelectric body. Accordingly, regardless of the shape, material, size, etc. of the resonator, the horizontal resonance suppression member (140) can be formed in an optimal shape at an optimal location, and thus spurious resonance caused by horizontal waves can be effectively limited, thereby enhancing resonance performance.

Meanwhile, the acoustic resonator according to the present invention is not limited to the configuration of the above-described embodiment and various modifications are possible.

FIG. 4 is a cross-sectional view illustrating a resonating portion of an acoustic resonator according to another embodiment of the present invention, and FIG. 5 is a graph comparing the insertion loss of the acoustic resonator illustrated in FIG. 4 and a conventional acoustic resonator.

Referring to FIGS. 4 and 5, the acoustic resonator according to the present embodiment has a horizontal resonance suppression member (140) formed thicker than in the previously described embodiment. In the previously described embodiment, the horizontal resonance suppression member (140) was formed with a thickness less than half the thickness of the piezoelectric layer (123), but the horizontal resonance suppression member (140) according to the present embodiment is formed with a thickness greater than half the thickness of the piezoelectric layer (123). More specifically, the horizontal resonance suppression member (140) is formed with the same thickness as the thickness of the piezoelectric layer (123).

When the horizontal resonance suppression unit (140) is configured in this manner, as shown in Fig. 5, it can be confirmed that the insertion loss is reduced compared to the conventional acoustic resonator. However, compared to Fig. 3, the noise reduction effect was measured to be somewhat lower than that of the above-described embodiment.

Fig. 6 is a cross-sectional view illustrating a resonating portion of an acoustic resonator according to another embodiment of the present invention. Also, Fig. 7 is a graph comparing the insertion loss of the acoustic resonator illustrated in Fig. 6 with that of a conventional acoustic resonator.

Referring to FIGS. 6 and 7, the acoustic resonator according to the present embodiment includes a second horizontal resonance suppression unit (140b) positioned at the center of a vibration active area (A) and a first horizontal resonance suppression unit (140a) positioned on the outer side of the second horizontal resonance suppression unit (140b).

The second horizontal resonance suppression member (140b) has a thickness thinner than that of the first horizontal resonance suppression member (140a). For example, the thickness of the second horizontal resonance suppression member (140b) may be formed to be less than half the thickness of the first horizontal resonance suppression member (140a).

The horizontal resonance suppression unit (140) illustrated in Fig. 6 is formed with a width ratio of 3:2 between the first horizontal resonance suppression unit (140a) and the second horizontal resonance suppression unit (140b), so that the width of the first horizontal resonance suppression unit (140a) is larger than the width of the second horizontal resonance suppression unit (140b).

In this way, the first horizontal resonance suppression unit (140a) and the second horizontal resonance suppression unit (140b) arranged within the vibration active area (A) can be configured to have different widths. However, this is not limited thereto, and, if necessary, the first horizontal resonance suppression unit (140a) and the second horizontal resonance suppression unit (140b) arranged within the vibration active area (A) can also be formed to have the same width.

Meanwhile, due to the difference in thickness between the second horizontal resonance suppression unit (140b) and the first horizontal resonance suppression unit (140a), a step-shaped difference is formed between the second horizontal resonance suppression unit (140b) and the first horizontal resonance suppression unit (140a), and thus, the horizontal resonance suppression unit (140) is configured to become thicker from the center of the vibration active area (A) toward the edge of the vibration active area (A).

The first horizontal resonance suppression unit (140a) and the second horizontal resonance suppression unit (140b) can be formed through separate ion injection processes, respectively. For example, the first horizontal resonance suppression unit (140a) can be first formed in the piezoelectric layer (123) through the first ion injection process, and then the second horizontal resonance suppression unit (140b) can be formed through the second ion injection process.

The first horizontal resonance suppression unit (140a) and the second horizontal resonance suppression unit (140b) may be configured to have the same physical properties or different physical properties.

In the present embodiment, both the first horizontal resonance suppression unit (140a) and the second horizontal resonance suppression unit (140b) are formed by injecting N ions into the piezoelectric layer (123) of AlN. Therefore, the first horizontal resonance suppression unit (140a) and the second horizontal resonance suppression unit (140b) have the same physical properties.

However, the configuration of the present invention is not limited to this. For example, the first horizontal resonance suppression unit (140a) may be configured to increase the piezoelectric performance through ion substitution, and the second horizontal resonance suppression unit (140b) may be configured to decrease the piezoelectric performance by destroying the lattice structure, or vice versa.

In addition, in this embodiment, the first horizontal resonance suppression part (140a) and the second horizontal resonance suppression part (140b) are formed with different thicknesses, but this is not limited to this, and it is also possible to configure the physical properties of the first horizontal resonance suppression part (140a) and the second horizontal resonance suppression part (140b) differently and form them with the same thickness.

Referring to Fig. 7, it can be confirmed that the acoustic resonator according to the present embodiment has a smaller insertion loss than the conventional acoustic resonator. In addition, referring to Figs. 3 and 6 together, it was measured that the noise reduction effect of the acoustic resonator according to the present embodiment is higher than that of the embodiments described above.

FIG. 8 is a cross-sectional view illustrating a resonating portion of an acoustic resonator according to another embodiment of the present invention.

Referring to FIG. 8, in the acoustic resonator according to the present embodiment, a horizontal resonance suppression member (140) is formed only within the vibration active area (A), and no horizontal resonance suppression member (140) is formed at the bottom or outside of the frame (170).

Suppression of horizontal wave resonance is mostly achieved by the horizontal resonance suppression unit (140) placed within the vibration active area (A). Therefore, the horizontal resonance suppression unit (140) can be omitted outside the vibration active area (A) as needed.

Next, a method for manufacturing the acoustic resonator module illustrated in FIGS. 1 and 2 is described.

FIGS. 9 to 11 are drawings for explaining a method for manufacturing the acoustic resonator illustrated in FIGS. 1 and 2.

Referring to Fig. 9, first, a sacrificial layer (131) is formed on top of the substrate (110).

The substrate (110) may be a silicon substrate or a SOI (Silicon On Insulator) substrate. In addition, the sacrificial layer (131) is removed later to form an air gap (130 in FIG. 1). The sacrificial layer (131) may be made of a material such as polysilicon or polymer.

Next, a membrane layer (150) is formed on the upper part of the substrate (110) and the upper part of the sacrificial layer (131). The membrane layer (150) maintains the shape of the air gap (130 in FIG. 1) and supports the structure of the resonant portion (120 in FIG. 1).

Next, the lower electrode (121) is formed.

The lower electrode (121) can be formed by depositing a conductive layer (not shown) over the entire upper portion of the substrate (110) and the sacrificial layer (131) and then removing unnecessary portions (e.g., patterning). The steps may be performed via a photolithography process, but are not limited thereto.

The above-mentioned challenge layer can be formed of a molybdenum (Mo) material. However, it is not limited thereto, and various metals such as gold, ruthenium, aluminum, platinum, titanium, tungsten, palladium, chromium, and nickel can be used.

Next, a piezoelectric layer (123) is formed.

The piezoelectric layer (123) can be formed by depositing a piezoelectric material on the lower electrode (121).

The piezoelectric layer (123) may be formed of aluminum nitride (AlN). However, it is not limited thereto, and various piezoelectric materials such as zinc oxide (ZnO) or quartz may be used.

Next, as shown in Fig. 10, a horizontal resonance suppression member (140) is formed within the piezoelectric layer (123). The horizontal resonance suppression member (140) can be formed by partially injecting ions into the piezoelectric layer (123).

As described above, the horizontal resonance suppression unit (140) can be implemented in various depths and shapes depending on the ion source, energy, dose, heat treatment temperature, and time.

For example, the horizontal resonance suppression member (140) can be formed by forming the piezoelectric layer (123) with AlN and injecting any one of Sc, Mg, Nb, Zr, and Hf ions into the piezoelectric layer (123) to replace a portion of the piezoelectric layer (123). In this case, the horizontal resonance suppression member (140) can have properties with higher piezoelectric performance than other portions where ions are not injected.

In addition, the horizontal resonance suppression portion (140) may be formed by intentionally destroying the lattice structure of the AlN piezoelectric layer (123) with ions such as Ar, Oxygen, B, P, and N. In this case, the horizontal resonance suppression portion (140) may have properties with lower piezoelectric performance than other portions where ions are not injected.

In this embodiment, the horizontal resonance suppression part (140) is formed on both the edge of the vibration-active region (A of FIG. 2) among the piezoelectric layer (123) and the outer part of the vibration-active region (A). In this case, since the horizontal resonance suppression part (140) is formed over a large area, there is an advantage in that it is easy to manufacture. However, the configuration of the present invention is not limited thereto, and various modifications are possible, such as forming the horizontal resonance suppression part (140) with a minimum area as in other embodiments described below.

Meanwhile, in the process of forming the horizontal resonance suppression unit (140), if the first horizontal resonance suppression unit (140a) and the second horizontal resonance suppression unit (140b) having different thicknesses are formed respectively, the acoustic resonator illustrated in FIG. 6 can be manufactured.

In this case, a first horizontal resonance suppression portion (140a) can be first formed within the piezoelectric layer (123) through a first ion injection process, and then a second horizontal resonance suppression portion (140b) can be formed through a second ion injection process.

In addition, the thickness of the first horizontal resonance suppression unit (140a) can be formed to be more than half the thickness of the piezoelectric layer (123), and the thickness of the second horizontal resonance suppression unit (140b) can be formed to be thinner than the first horizontal resonance suppression unit (140a).

Accordingly, as illustrated in FIG. 6, a horizontal resonance suppression member (140) can be formed whose thickness becomes thicker from the center of the vibration active region (A) toward the edge of the vibration active region (A).

Referring again to FIG. 10, a method for manufacturing the acoustic resonator illustrated in FIG. 2 will be described. After the horizontal resonance suppression portion (140) is formed, an upper electrode (125) and a frame (170) are formed on top of the piezoelectric layer (123), and then the upper electrode (125) is patterned.

Thereafter, as shown in Fig. 11, the piezoelectric layer (123) is patterned. As a result, the vibration active area (A) shown in Fig. 2 is completed.

When the vibration active region (A) is completed, a protective layer (127) and first and second connection electrodes (160a, 160b) are sequentially formed. Then, the sacrificial layer (131) is removed to complete the acoustic resonator illustrated in Fig. 1. Here, the sacrificial layer (131) can be removed through an etching method.

Meanwhile, the method for manufacturing an acoustic resonator according to the present invention is not limited to the above-described embodiment, and various modifications are possible.

Figures 12 and 13 are drawings for explaining a method for manufacturing the acoustic resonator illustrated in Figure 8.

The method for manufacturing an acoustic resonator according to the present embodiment is performed in the same manner as the previously described embodiment up to the process illustrated in Fig. 9. Therefore, the description will be given from the step illustrated in Fig. 9 onwards.

Referring to Fig. 12, a horizontal resonance suppression member (140) is formed within the piezoelectric layer (123). The horizontal resonance suppression member (140) can be formed by partially injecting ions into the piezoelectric layer (123).

In the present embodiment, the horizontal resonance suppression part (140) is formed only within the vibration active region (A of FIG. 8) of the piezoelectric layer (123). In this case, since the change in the physical properties of the piezoelectric layer (123) can be minimized, the change in the piezoelectric performance of the piezoelectric layer (123) due to the horizontal resonance suppression part (140) that is unnecessarily formed can be minimized.

Next, an upper electrode (125) and a frame (170) are formed on top of the piezoelectric layer (123), and then the upper electrode (125) is patterned.

Thereafter, as shown in Fig. 13, after patterning the piezoelectric layer (123), a protective layer (127) and first and second connection electrodes (160a, 160b) are sequentially formed. Then, the sacrificial layer (131) is removed to complete the acoustic resonator shown in Fig. 8.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it will be apparent to those skilled in the art that various modifications and variations are possible within a scope that does not depart from the technical spirit of the present invention described in the claims.

110: Substrate
120: Resonance section
121: Lower electrode 123: Piezoelectric layer
125: Upper electrode
130: Air gap 131: Sacrificial layer
140: Horizontal resonance suppression section 150: Membrane layer
170: Frame

Claims (16)

substrate;
A vibration active region formed by sequentially stacking a lower electrode, a piezoelectric layer, and an upper electrode on the substrate; and
A horizontal resonance suppressor disposed within the piezoelectric layer but having different properties from the piezoelectric layer;
The above horizontal resonance suppression unit is an acoustic resonator including a first horizontal resonance suppression unit and a second horizontal resonance suppression unit having different thicknesses.
substrate;
A vibration active region formed by sequentially stacking a lower electrode, a piezoelectric layer, and an upper electrode on the substrate; and
A horizontal resonance suppressor disposed within the piezoelectric layer but having different properties from the piezoelectric layer;
The above horizontal resonance suppression member is an acoustic resonator formed with a thickness that becomes thicker as it goes from the center of the vibration active region to the edge of the vibration active region.
substrate;
A vibration active region formed by sequentially stacking a lower electrode, a piezoelectric layer, and an upper electrode on the substrate; and
A horizontal resonance suppressor disposed within the piezoelectric layer but having different properties from the piezoelectric layer;
The above horizontal resonance suppression member is an acoustic resonator formed with a thickness less than half of the thickness of the piezoelectric layer.
In any one of claims 1 to 3, the horizontal resonance suppression unit,
An acoustic resonator, partly or entirely disposed within said vibrating active region.
In the fourth paragraph, the horizontal resonance suppression unit,
Acoustic resonators arranged along the border of the above vibration active region.
In the first paragraph, the first horizontal resonance suppression unit and the second horizontal resonance suppression unit,
Acoustic resonators formed with identical physical properties.
In the first paragraph, the second horizontal resonance suppression unit,
An acoustic resonator formed with the same thickness as the above piezoelectric layer.
delete In any one of claims 1 to 3, the horizontal resonance suppression unit,
An acoustic resonator having properties that have higher piezoelectric performance than the above piezoelectric layer.
In any one of claims 1 to 3, the horizontal resonance suppression unit,
An acoustic resonator having properties lower than the piezoelectric layer.
In paragraph 4,
An acoustic resonator in which the upper surface area of the horizontal resonance suppression member disposed within the vibration active region is formed to be 50% or less of the total upper surface area of the vibration active region.
A step of sequentially laminating a lower electrode and a piezoelectric layer on a substrate;
A step of partially injecting ions into the piezoelectric layer to form a horizontal resonance suppression portion within the piezoelectric layer; and
A step of laminating an upper electrode on the piezoelectric layer to complete a vibration active region; including;
A method for manufacturing an acoustic resonator, wherein the step of forming the horizontal resonance suppression unit includes the step of forming a first horizontal resonance suppression unit and a second horizontal resonance suppression unit having different thicknesses.
In the 12th paragraph, the horizontal resonance suppression unit,
A method for manufacturing an acoustic resonator, wherein part or all of the resonator is formed within the vibrationally active region.
delete In the 12th paragraph, the step of forming the horizontal resonance suppression unit is:
A method for manufacturing an acoustic resonator, comprising the step of replacing a portion of a piezoelectric layer formed of AIN by injecting any one of Sc, Mg, Nb, Zr, and Hf ions into the piezoelectric layer.
In the 12th paragraph, the step of forming the horizontal resonance suppression unit is:
A method for manufacturing an acoustic resonator, comprising the step of destroying the lattice structure of the piezoelectric layer formed of AIN by injecting any one of Ar, Oxygen, B, P, and N ions into the piezoelectric layer.

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