JP2006020277A - Thin film bulk acoustic resonator and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the spurious caused by a lateral vibration mode. <P>SOLUTION: The thin film bulk acoustic resonator includes a laminated body having a first electrode comprised of at least one conductive layer formed on a supporting substrate, at least one piezoelectric layer adjacently formed on an upper surface of the first electrode, and a second electrode comprised of at least one conductive layer adjacently formed on an upper surface of the piezoelectric layer, and has a structure where an end face of the piezoelectric layer appears by removing the piezoelectric layer positioned near an outer peripheral edge of the second electrode and at least a part of the end face is positioned inside the second electrode. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thin-film bulk acoustic resonator suitable for application to a small high-frequency filter used in communication equipment and a method for manufacturing the same.

  In recent years, with the increase in functionality and speed of communication devices such as mobile phones and PDAs (personal digital assistants), the number of built-in high frequency filters operating from several hundred MHz to several GHz has increased. Therefore, there is a demand for downsizing and cost reduction. A promising candidate for a high-frequency filter that satisfies this requirement is a filter composed of a thin-film bulk acoustic resonator that utilizes the electroacoustic effect exhibited by a piezoelectric layer that can be formed using semiconductor manufacturing technology.

  As a typical conventional example of this thin film bulk acoustic resonator, there is one shown in FIG. 15 and FIG. 16 called an air bridge type described in Non-Patent Document 1. FIG. 15 is a plan view of an example of this air bridge type thin film bulk acoustic resonator, and FIG. 16 is a cross-sectional view taken along line AA of FIG.

  As shown in FIGS. 15 and 16, this conventional air-bridge type thin film bulk acoustic resonator has a rectangular lower part having a thickness of 0.1 to 0.5 μm on a support substrate 1 made of high resistance silicon or high resistance gallium arsenide. An electrode 3 is provided.

  A piezoelectric layer 4 having a thickness of about 1 to 2 μm is provided on the lower electrode 3, and a rectangular upper electrode 5 having a thickness of about 0.1 to 0.5 μm is provided on the piezoelectric layer 4.

  The lower electrode 3, the piezoelectric layer 4 and the upper electrode 5 are sequentially formed using a sputter deposition technique well known in the semiconductor manufacturing technique and various etching techniques using a resist as a mask.

  For example, molybdenum, tungsten, titanium, platinum, ruthenium, aluminum or the like is used as the lower electrode 3 and the upper electrode 5, and aluminum nitride or zinc oxide is used as the piezoelectric layer 4, for example.

  An air layer 2 having a thickness of about 0.5 to 3 μm is formed immediately below a region where the upper electrode 5 and the lower electrode 3 overlap with each other via the piezoelectric layer 4 (that is, a region operating as a thin film bulk acoustic resonator). The lower electrode 3 also has a boundary surface in contact with air, like the upper electrode 5.

  The air layer 2 includes a silicon oxide film, a PSG film (a silica glass film added with phosphorous silicate glass phosphorus), a BPSG film (a silica glass film added with boron and phosphorus), an SOG film, etc. FIG. It is formed by etching away with an HF aqueous solution through a via hole 6 as shown in FIG.

  Next, the operation of the thin film bulk acoustic resonator shown in FIGS. 15 and 16 will be described.

  When an alternating voltage is applied between the upper electrode 5 and the lower electrode 3 to generate a time-varying electric field in the piezoelectric layer 4, the piezoelectric layer 4 generates a part of electric energy as an elastic wave. It is converted to mechanical energy in the form of (hereinafter referred to as sound waves).

  This mechanical energy is propagated in the film thickness direction of the piezoelectric layer 4, which is the direction perpendicular to the electrode surfaces of the upper electrode 5 and the lower electrode 3, and is converted back into electrical energy. There is a specific frequency that is highly efficient in the electrical / mechanical energy conversion process, and when an AC voltage having this frequency is applied, the thin film bulk acoustic resonator exhibits a very low impedance.

This specific frequency is generally called the resonance frequency γ, and its value γ is a first order approximation, and when the presence of the upper electrode 5 and the lower electrode 3 is ignored,
γ = V / (2t)
Given in. Here, V is the velocity of the sound wave in the piezoelectric layer 4, and t is the thickness of the piezoelectric layer 4.

If the wavelength of the sound wave is λ,
V = γλ
Since the relationship of
t = λ / 2
It becomes.

  This is because the sound wave induced in the piezoelectric layer 4 repeatedly reflects up and down at the boundary surface between the piezoelectric layer 4 and the upper electrode 5 and the lower electrode 3, and a standing wave corresponding to the half wavelength is formed. Means that

  In other words, the resonance frequency γ is when the frequency of the sound wave where the standing wave of half wavelength is standing matches the frequency of the externally applied AC voltage.

  By utilizing the fact that the impedance of this thin film bulk acoustic resonator becomes extremely small at this resonance frequency, a plurality of thin film bulk acoustic resonators are assembled in a ladder shape, and only electrical signals in a desired frequency band are passed with low loss. A band-pass filter is introduced in Non-Patent Document 1.

  For example, as shown in FIG. 17 (region operating as the thin film bulk acoustic resonator of FIGS. 15 and 16), this thin film bulk acoustic resonator has a vibration mode (hereinafter referred to as main vibration) that stands in the direction perpendicular to the electrode surface as described above. A sound wave 7 of a vibration mode (hereinafter referred to as a transverse vibration mode) propagating in a direction parallel to the electrode surface is also induced.

  The sound wave 8 in the transverse vibration mode is repeatedly reflected on the boundary surface where the acoustic impedance greatly changes, such as the virtual vertical surface 9 in the piezoelectric layer 4 at the end of the upper electrode 5 and the end surface of the piezoelectric layer 4. When the standing wave of 8 is formed, the resonance characteristics and quality factor of this thin film bulk acoustic resonator or a bandpass filter using this thin film bulk acoustic resonator are greatly deteriorated.

  Specifically, since the transverse vibration mode sound wave 8 propagates a longer distance than the main vibration mode sound wave 7, the frequency of the transverse vibration mode sound wave 8 is the frequency of the main vibration mode sound wave 7, that is, the resonance frequency. Although it is considerably lower than γ, the harmonic component of the sound wave 8 in the transverse vibration mode may have a frequency in the vicinity of the resonance frequency γ, and noise called spurious is generated in the resonance characteristics of the thin film bulk acoustic resonator. . If a bandpass filter is configured, ripples are generated in the pass frequency band, causing an unnecessary large insertion loss.

Conventionally, for the purpose of improving the spurious attributed to the transverse vibration mode, an improvement plan has been proposed in which the end face of the piezoelectric layer 4 is formed in a non-vertical shape outside the upper electrode 5 (Patent Document 1). FIG. 17). When the end face of the piezoelectric layer 4 has a non-vertical shape, it is difficult to generate a standing wave in the transverse vibration mode by dispersing the sound wave 8 in the transverse vibration mode that has reached the end face.
Special table 2003-505906 gazette KMLakin “Thin film resonator and filters” Proceedings of the 1999 IEEE Ultrasonics Symposium, Vol.2, pp895-906, 17-20 Oct.1999.

  However, in the description of Patent Document 1, the transverse vibration mode sound wave 8 reaching the end face of the piezoelectric layer 4 is dispersed, but most of the reflection of the transverse vibration mode sound wave 8 is as shown in FIG. Since the noise occurs not on the end face of the layer 4 but on the virtual reflecting surface 9 perpendicular to the end of the upper electrode 5, even if the outer side of the upper electrode 5 of the piezoelectric layer 4 has a non-vertical shape, spurious due to the transverse vibration mode. There were few inconveniences to the suppression effect.

  In view of this point, an object of the present invention is to reduce spurious due to the transverse vibration mode.

  A thin film bulk acoustic resonator according to the present invention includes a first electrode made of at least one conductive layer formed on a support substrate, and at least one layer formed adjacent to the upper surface of the first electrode. A thin film bulk acoustic resonator comprising a laminate of a piezoelectric layer comprising a piezoelectric material layer and a second electrode comprising at least one conductive layer formed adjacent to the upper surface of the piezoelectric layer; By removing the piezoelectric layer located at least near the outer peripheral edge of the electrode, the piezoelectric layer has a structure in which the end face appears, and at least a part of the end face is located inside the second electrode. It is a structure to do.

  In the above-described thin film bulk acoustic resonator according to the present invention, the end face of the piezoelectric layer is not perpendicular to the second electrode, but has an uneven shape having an inclination and no periodicity.

  According to the present invention, by removing the piezoelectric layer located at least in the vicinity of the outer peripheral end of the second electrode, the piezoelectric layer has a structure in which the end face appears, and at least a part of the end face has this structure. Since the structure is located inside the second electrode and the piezoelectric layer corresponding to the end of the second electrode is eliminated, a virtual reflecting surface perpendicular to the end of the second electrode of the piezoelectric layer is formed. Since there is no reflection of the sound wave in the transverse vibration mode by this portion, spurious due to the transverse vibration mode can be reduced.

  Further, according to the present invention, when the end face of the piezoelectric layer is not uneven with respect to the second electrode but is inclined and has an irregular shape having no periodicity, the reflection of the sound wave in the transverse vibration mode on the end face is as follows. It becomes irregular reflection and the standing wave of this sound wave does not stand up, and as a result, spurious can be reduced.

  Hereinafter, an example of the best mode for carrying out the thin film bulk acoustic resonator of the present invention and the manufacturing method thereof will be described with reference to FIGS.

  The thin film bulk acoustic resonator according to this example has the structure shown in FIG. 1 to FIG. 3, FIG. 2 is a plan view, and FIG. 1 is a cross-sectional view taken along the line II in FIG. The thin film bulk acoustic resonator according to this example shown in FIGS. 1 to 3 includes a lower electrode 22 made of a conductive layer formed on a support substrate 20 and a piezoelectric body formed adjacent to the upper surface of the lower electrode 22. This piezoelectric body is composed of a laminate of a layer 23 and an upper electrode 24 made of a conductive layer formed adjacent to the upper surface of the piezoelectric layer 23, and is located at least near the outer peripheral end of the upper electrode 24. By removing the layer 23, the end face 51 of the piezoelectric layer 23 appears and at least a part of the end face 51 is located inside the upper electrode 24.

  In this example, the thickness of 0.5 to 0.5 is directly below the region where the upper electrode 24 and the lower electrode 22 overlap with each other via the piezoelectric layer 23 (that is, the region operating as a thin film bulk acoustic resonator). An air layer 21 of about 3 μm is formed, and the lower electrode 22 has a boundary surface in contact with air, like the upper electrode 24.

  Next, an example of a method for manufacturing the thin film bulk acoustic resonator shown in FIGS. 1 to 3 will be described with reference to FIGS.

  First, as shown in FIG. 4, a rectangular hole (concave portion) 31 having a predetermined size to be an air layer 21 is formed in a support substrate 20 made of high resistance silicon or high resistance gallium arsenide having a specific resistance exceeding 1000 Ωcm. To do. The depth of the hole (concave portion) 31 is set to about 0.5 to 3 μm.

  Next, a sacrificial layer 32 having a thickness equal to or greater than the depth of the hole (recess) 31 is deposited and formed in the hole (recess) 31. The sacrificial layer 32 is a silicon oxide film, a PSG film, a BPSG film, an SOG film, or the like. After the sacrificial layer 32 is formed, the sacrificial layer 32 is etched back by CMP (chemical mechanical polishing) or the like as shown in FIG. 5, and the remaining sacrificial layer 32 and the surface of the support substrate 20 coincide with each other. To form.

  Thereafter, the lower electrode 22 is deposited and formed on the sacrificial layer 32 and the support substrate 20 across the sacrificial layer 32 as shown in FIG. As this lower electrode 22, molybdenum, tungsten, platinum, ruthenium or the like is used. When molybdenum is used, the thickness of the lower electrode 22 is desirably about 0.1 to 0.5 μm, and is 0.23 μm in this example. After this lower electrode 22 was deposited, it was formed into a pattern having a desired planar shape using various etching techniques using a resist as a mask.

  Next, as shown in FIG. 7, a piezoelectric layer 23 having a thickness of about 1 to 2 μm is deposited using a sputter deposition technique. As the piezoelectric layer 23, for example, aluminum nitride or zinc oxide is used.

  Thereafter, as shown in FIG. 8, an upper electrode 24 is deposited on the piezoelectric layer 23 by using a sputter deposition technique. As the upper electrode 24, molybdenum was used in the same manner as the lower electrode 22, and the film thickness was set to 0.23 μm. As the upper electrode 24, molybdenum, tungsten, platinum, ruthenium or the like can be used, and the film thickness is preferably 0.1 to 0.5 μm. After depositing the upper electrode 24, various etching techniques using a resist as a mask were used to form a desired planar shape, for example, a square pattern of 100 μm × 100 μm.

  Next, as shown in FIG. 9, a part of the piezoelectric layer 23 is etched from the surface side using the upper electrode 24 as a mask so that the end face 51 of the piezoelectric layer 23 appears. For example, when an aluminum nitride layer having a film thickness of 1.2 μm is used as the piezoelectric layer 23, it is immersed in a developer heated to about 38 to 40 ° C. (for example, product name NMD-3, manufactured by Tokyo Ohka Kogyo Co., Ltd.) for 7 to 9 minutes. An aluminum nitride layer having a thickness of about 0.8 μm can be etched.

  In this case, since the developing solution exhibits anisotropic etching characteristics with respect to the aluminum nitride layer, the end face 51 of the aluminum nitride layer which is the piezoelectric layer 23 basically has a taper angle of about 57 degrees, but actually In many cases, the etching proceeds frequently using the non-uniformity scattered on the surface or inside of the aluminum nitride layer as a mask, and as a result, a cross-sectional shape in which a large number of minute conical structures are scattered as shown in FIG. Is formed.

  In this case, as shown in FIG. 9, a minute cone appears on the end face 51 of the piezoelectric layer 23, and as a result, irregular irregularities are formed. When the occurrence frequency of the microcone appearing on the end face 51 is high, the intersection line where the end face 51 and the upper electrode 24 intersect has an irregular curve section, but when the frequency is low, the formation of the microcone is an intersection line. The intersecting line reflects almost the shape of the outer peripheral end of the upper electrode 24.

  In any case, irregular irregularities on the end face 51 due to the generation of micro cones at the time of etching occur to some extent, and reflection of sound waves in the transverse vibration mode is irregularly reflected and standing waves are generated. Therefore, spurious generated near the anti-resonance frequency is suppressed as will be described later.

  In this case, the line of intersection with the upper electrode 24 at the upper end of the end surface 51 of the piezoelectric layer 23 is located inside the upper electrode 24. The distance L at which the line of intersection between the end face 51 and the upper electrode 24 penetrates into the upper electrode 24 is defined as α when the thickness of the aluminum nitride layer, which is the piezoelectric layer 23 removed by etching, is α. The maximum was 2α with the etching along the interface with molybdenum, which is the upper electrode 24, starting from the outer peripheral edge.

  In this case, as shown in FIG. 9, the piezoelectric layer 23 located near and outside the outer peripheral edge of the upper electrode 24 is removed so as to leave a part instead of all in the thickness direction view. An end face 51 is made to appear.

  Next, as shown in FIG. 10, a via hole 26 penetrating the piezoelectric layer 23 and the lower electrode 22 and reaching the sacrificial layer 32 is formed, and the sacrificial layer 32 is completely removed with an HF aqueous solution through the via hole 26. Thus, an air layer 21 is formed, and a thin film bulk acoustic resonator as shown in FIGS. 1 and 3 is obtained.

  Next, the operation of the thin film bulk acoustic resonator shown in FIGS. 1 to 3 will be described.

  When an alternating voltage is applied between the upper electrode 24 and the lower electrode 22 to generate a time-varying electric field inside the piezoelectric layer 23, the piezoelectric layer 23 generates a part of electric energy as an elastic wave. It is converted to mechanical energy in the form of (hereinafter referred to as sound waves).

  This mechanical energy (sound wave 41 in the main vibration mode) is propagated in the film thickness direction of the piezoelectric layer 23, which is perpendicular to the electrode surfaces of the upper electrode 24 and the lower electrode 22, as shown in FIG. Is converted. There is a specific frequency that is highly efficient in the electrical / mechanical energy conversion process, and when an AC voltage having this frequency is applied, the thin film bulk acoustic resonator exhibits a very low impedance.

This specific frequency is generally called the resonance frequency γ, and its value γ is a first order approximation, and when the presence of the upper electrode 24 and the lower electrode 22 is ignored,
γ = V / (2t)
Given in. Here, V is the speed of sound waves in the piezoelectric layer 23, and t is the thickness of the piezoelectric layer 23.

If the wavelength of the sound wave is λ,
V = γλ
Since the relationship of
t = λ / 2
It becomes.

  This is because the sound wave induced in the piezoelectric layer 23 repeatedly reflects up and down at the boundary surface between the piezoelectric layer 23 and the upper electrode 24 and the lower electrode 22, and a standing wave corresponding to the half wavelength is formed. Means that

  In other words, the resonance frequency γ is when the frequency of the sound wave where the standing wave of half wavelength is standing matches the frequency of the externally applied AC voltage.

  According to this example, since the upper end of the end surface 51 that appears by etching the piezoelectric layer 23 using the upper electrode 24 as a mask is located inside the outer peripheral end of the upper electrode 24, the outer peripheral end of the upper electrode 24 There is no piezoelectric layer 23 adjacent to. Therefore, as shown in FIG. 3, there is no virtual reflection surface perpendicular to the upper electrode 24 at the outer peripheral edge of the upper electrode 24, and there is no reflection of the sound wave 42 in the transverse vibration mode by this portion, which is caused by the transverse vibration mode. Spurious to be reduced can be reduced.

  Further, according to this example, since the end face 51 appears by etching the piezoelectric layer 23 using the upper electrode 24 as a mask, the end face 51 is not perpendicular to the upper electrode 24 but has an inclination and has periodicity. Since there is no uneven shape, as shown in FIG. 3, the reflection of the sound wave 42 in the transverse vibration mode on the end face 51 is irregular reflection. For this reason, the standing wave of the sound wave 42 does not stand, and as a result, spurious can be reduced.

  Incidentally, a thin film bulk acoustic resonator having a configuration as shown in FIG. 1 is prototyped, and the result of actually measuring the impedance by changing the frequency of the AC voltage is shown in FIG. For comparison, FIG. 14 shows the results of trial manufacture and measurement of a configuration in which the piezoelectric layer 4 is not etched as shown in FIG. The impedance value shown here is normalized by a capacitance value when the thin film bulk acoustic resonator is regarded as a simple parallel plate capacitance.

  As the configuration of this thin film bulk acoustic resonator, molybdenum is used as the upper electrodes 24 and 5 and the lower electrodes 22 and 3, the thickness is 0.23 μm, respectively, and aluminum nitride is used as the piezoelectric layers 23 and 4. The thickness was 1.2 μm, and the upper electrodes 24 and 5 were squares of 100 μm × 100 μm. Further, the piezoelectric layer 23, that is, the aluminum nitride layer was etched by 0.7 μm to form a disordered uneven shape on the end face 51.

  As shown in FIG. 17, the conventional thin film bulk acoustic resonator in which the thickness of the aluminum nitride layer as the piezoelectric layer 4 is the same inside and outside the outer peripheral edge of the upper electrode 5 is shown in FIG. At 92 GHz and in the vicinity thereof, the impedance changes greatly like noise, and spurious due to the transverse vibration mode is remarkably confirmed.

  On the other hand, the thin film bulk acoustic resonator according to the present example shown in FIG. 1 has a relatively smooth characteristic with spurious reductions near the antiresonance frequency of 1.963 GHz as shown in FIG. This means that, according to this example, spurious due to the transverse vibration mode is suppressed.

  In the manufacturing example described above, the sacrificial layer 32 is removed after the piezoelectric layer 23 is etched with the developer. However, the sacrificial layer 32 may be removed before the piezoelectric layer 23 is etched. Of course.

  In the above-described example, the piezoelectric layer 23 is etched with a developing solution using the upper electrode 24 as a mask, but this piezoelectric film is added with a protective film such as a resist, a silicon oxide film, or a silicon nitride film. The body layer 23 may be etched. In the above example, molybdenum is used for the upper electrode 24 and the piezoelectric layer 23 is etched with a developing solution using this as a mask. However, when a metal that is not insoluble (insoluble) in the developing solution is used for the upper electrode 24, this protective film is formed. is necessary.

  In the above-described example, the developer is used to etch the piezoelectric layer 23, but other chemicals may be used instead.

  In the example shown in FIG. 1 described above, by removing the piezoelectric layer 23 located in the vicinity of the outer peripheral edge of the upper electrode 24 and on the outer side so as to leave a part instead of all in the thickness direction view, In this structure, the end face 51 appears. Instead, as shown in FIG. 11, the piezoelectric layer 23 only in the vicinity of the outer periphery of the upper electrode 24 is etched using the resist as a mask, It is also possible to form at least a part of the end face 51 directly below and to form irregular irregularities having no periodicity on the end face 51.

  It can be easily understood that the same operational effects as in FIG. 1 can be obtained in the example of FIG.

  FIG. 12 also shows another example of the best mode for carrying out the present invention. This example of FIG. 12 is the same as that of FIG. 1 so that the end face 51 of the piezoelectric layer 23 appears by completely removing the piezoelectric layer 23 located near and on the outer periphery of the upper electrode 24 in the thickness direction. It is a thing.

  In the example of FIG. 12 as well, at least a part of the end surface 51 is formed immediately below the inner periphery in the vicinity of the outer peripheral end of the upper electrode 24, and irregular irregularities having no periodicity are formed on the end surface 51, and the same action as in FIG. It can be easily understood that the effect can be obtained.

  In the above-described example, the example in which the upper electrode 24 and the lower electrode 22 are formed of a single conductive layer has been described. However, the upper electrode 24 and the lower electrode 22 may be configured by a plurality of conductive layers. Of course.

  In the above-described example, the example in which the piezoelectric layer 23 is formed of a single piezoelectric layer has been described, but it is needless to say that the piezoelectric layer 23 may be configured by a plurality of piezoelectric layers.

  In the above example, the upper electrode 24 has a square shape, but this shape is a rectangle having parallel opposite sides, a trapezoid, a parallelogram, other polygons, a triangle having no parallel opposite sides, and other shapes. It may be an arbitrary shape such as a polygonal shape, a circular shape, a semi-circular shape, an elliptical shape or the like in which a part is a curved line.

  In the above example, the air layer 21 is provided on the support substrate 20 below the lower electrode 22. However, instead of air, a gas such as nitrogen or an inert gas is put into the air layer 21. Of course, it is also good.

  Further, instead of the air layer 21, as described in Non-Patent Document 1, an acoustic reflection mirror capable of effectively reflecting the sound wave 41 in the main vibration mode similarly to the air layer 21 is formed with the lower electrode 22 and the support substrate 20. Of course, it may be inserted in between.

  Further, it is needless to say that the present invention can be similarly applied to a stacked thin film bulk acoustic resonator which is a modification of the thin film bulk acoustic resonator.

  Further, the present invention is not limited to the above-described example, and various other configurations can be adopted without departing from the gist of the present invention.

It is the II sectional view taken on the line of FIG. 2 which shows the example of the best form for implementing this invention thin film bulk acoustic resonator. It is a top view of FIG. It is the II sectional view taken on the line of FIG. 2 with which it uses for description of operation | movement of this example. It is sectional drawing with which it uses for description of the example of the manufacturing method by this invention. It is sectional drawing with which it uses for description of the example of the manufacturing method by this invention. It is sectional drawing with which it uses for description of the example of the manufacturing method by this invention. It is sectional drawing with which it uses for description of the example of the manufacturing method by this invention. It is sectional drawing with which it uses for description of the example of the manufacturing method by this invention. It is sectional drawing with which it uses for description of the example of the manufacturing method by this invention. It is sectional drawing with which it uses for description of the example of the manufacturing method by this invention. It is sectional drawing which shows the other example of the best form for implementing this invention. It is sectional drawing which shows the other example of the best form for implementing this invention. It is an electrical property figure with which it uses for description of this invention. It is an electrical characteristic figure with which it uses for description of a prior art example. It is a top view of the example of the conventional thin film bulk acoustic resonator. It is the sectional view on the AA line of FIG. It is sectional drawing of the principal part of FIG.

Explanation of symbols

  20 ... Support substrate, 21 ... Air layer, 22 ... Lower electrode, 23 ... Piezoelectric layer, 24 ... Upper electrode, 51 ... End face

Claims (14)

A first electrode comprising at least one conductive layer formed on a support substrate;
A piezoelectric layer comprising at least one layer formed adjacent to the upper surface of the first electrode; and a second electrode comprising at least one conductive layer formed adjacent to the upper surface of the piezoelectric layer; In a thin film bulk acoustic resonator composed of a laminate of
An end face of the piezoelectric layer appears by removing the piezoelectric layer located at least near the outer peripheral edge of the second electrode, and at least a part of the end face of the second electrode A thin film bulk acoustic resonator, characterized in that it has a structure located inside. The thin film bulk acoustic resonator of claim 1,
The piezoelectric layer positioned only in the vicinity of the outer peripheral end of the second electrode is removed so as to leave a part in the thickness direction view, and the end surface of the piezoelectric layer is made to appear. Thin film bulk acoustic resonator. The thin film bulk acoustic resonator of claim 1,
A structure in which the end face of the piezoelectric layer is made to appear by removing the piezoelectric layer located near and outside the outer peripheral end of the second electrode so as to leave a part in the thickness direction view. Thin film bulk acoustic resonator. The thin film bulk acoustic resonator of claim 1,
A thin film bulk having a structure in which an end face of the piezoelectric layer appears by completely removing the piezoelectric layer located near and outside the outer peripheral end of the second electrode in the thickness direction. Acoustic resonator. The thin film bulk acoustic resonator according to claim 1, 2, 3 or 4,
The thin film bulk acoustic resonator according to claim 1, wherein an end face of the piezoelectric layer has an inclination that is not perpendicular to the second electrode. The thin film bulk acoustic resonator according to claim 1, 2, 3 or 4,
The thin film bulk acoustic resonator is characterized in that an end face of the piezoelectric layer is not perpendicular to the second electrode but has an inclination and has an irregular shape having no periodicity. The thin film bulk acoustic resonator according to claim 5 or 6,
When the piezoelectric layer is removed by etching and the thickness of the piezoelectric layer removed by the etching is α, the end of the end face is the second end from the outer peripheral end of the second electrode. A thin film bulk acoustic resonator, characterized in that a distance penetrating inside the electrode is 2α or less. The thin film bulk acoustic resonator according to claim 1, 2, 3, 4, 5, 6 or 7,
A thin film bulk acoustic resonator, wherein a gas layer or an acoustic reflection mirror is inserted between the first electrode and the support substrate. A first electrode comprising at least one conductive layer formed on a support substrate; at least one piezoelectric layer formed adjacent to the upper surface of the first electrode; and the piezoelectric layer A layered body with a second electrode made of at least one conductive layer formed adjacent to the upper surface of
An end face of the piezoelectric layer appears by removing the piezoelectric layer located in the vicinity of the outer peripheral end of the second electrode, and at least a part of the end face has a structure of the second electrode. In the method of manufacturing a thin film bulk acoustic resonator having a structure located inside,
A method of manufacturing a thin-film bulk acoustic resonator, comprising: removing a portion of the exposed piezoelectric layer so as to leave a part in a thickness direction view, using a resist having an opening only in the vicinity of the second outer peripheral edge as a mask. A first electrode comprising at least one conductive layer formed on a support substrate; at least one piezoelectric layer formed adjacent to the upper surface of the first electrode; and the piezoelectric layer A layered body with a second electrode made of at least one conductive layer formed adjacent to the upper surface of
An end face of the piezoelectric layer appears by removing the piezoelectric layer located in the vicinity of the outer peripheral end of the second electrode, and at least a part of the end face has a structure of the second electrode. In the method of manufacturing a thin film bulk acoustic resonator having a structure located inside,
A thin-film bulk characterized by etching away the exposed piezoelectric layer so as to leave a part in the thickness direction view, using an insulating film having a pattern in which only the vicinity of the outer peripheral edge of the second electrode is opened as a mask. A method for manufacturing an acoustic resonator. A first electrode comprising at least one conductive layer formed on a support substrate; at least one piezoelectric layer formed adjacent to the upper surface of the first electrode; and the piezoelectric layer A layered body with a second electrode made of at least one conductive layer formed adjacent to the upper surface of
An end face of the piezoelectric layer appears by removing the piezoelectric layer located in the vicinity of the outer peripheral end of the second electrode, and at least a part of the end face of the second electrode In the method of manufacturing a thin film bulk acoustic resonator having a structure located inside,
A method of manufacturing a thin-film bulk acoustic resonator, comprising: removing a part of the exposed piezoelectric layer so as to leave a part thereof, using a resist having an opening near and at an outer peripheral end of the second electrode as a mask. A first electrode comprising at least one conductive layer formed on a support substrate; at least one piezoelectric layer formed adjacent to the upper surface of the first electrode; and the piezoelectric layer A layered body with a second electrode made of at least one conductive layer formed adjacent to the upper surface of
An end face of the piezoelectric layer appears by removing the piezoelectric layer located in the vicinity of the outer peripheral end of the second electrode, and at least a part of the end face of the second electrode In the method of manufacturing a thin film bulk acoustic resonator having a structure located inside,
Using the insulating film having a pattern in which the vicinity of the outer peripheral edge of the second electrode and the inside of the second electrode are opened as a mask, the exposed piezoelectric layer is etched away so as to leave a part in the thickness direction view. A method for manufacturing a thin film bulk acoustic resonator. A first electrode comprising at least one conductive layer formed on a support substrate; at least one piezoelectric layer formed adjacent to the upper surface of the first electrode; and the piezoelectric layer A layered body with a second electrode made of at least one conductive layer formed adjacent to the upper surface of
The piezoelectric layer has a structure in which the end face of the piezoelectric layer appears by removing the piezoelectric layer located near and on the outer peripheral end of the second electrode so as to leave a part in the thickness direction view, and the end face In the method of manufacturing a thin film bulk acoustic resonator, at least a part of the structure is located inside the second electrode.
Using the second electrode as a mask, the exposed piezoelectric layer is removed by etching so as to leave a part in a thickness direction view. A first electrode comprising at least one conductive layer formed on a support substrate; at least one piezoelectric layer formed adjacent to the upper surface of the first electrode; and the piezoelectric layer A layered body with a second electrode made of at least one conductive layer formed adjacent to the upper surface of
The piezoelectric layer has a structure in which the end face of the piezoelectric layer appears by removing the piezoelectric layer located near and on the outer peripheral end of the second electrode so as to leave a part in the thickness direction view, and the end face In the method of manufacturing a thin film bulk acoustic resonator, at least a part of the structure is located inside the second electrode.
A method of manufacturing a thin-film bulk acoustic resonator, comprising: removing a part of the exposed piezoelectric layer in a thickness direction view, using a resist or insulating film protecting the second electrode as a mask.

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