JP2015186240A - Piezoelectric vibration piece, piezoelectric vibrator, and method of manufacturing piezoelectric vibration piece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric vibration piece which has excellent vibration characteristics.SOLUTION: A piezoelectric vibration piece 10 formed by AT cut and comprising a piezoelectric plate 20 provided with a first principal surface 21, a second principal surface 23, and side surfaces 25 comprises: a first mesa part 41 formed on the first principal surface 21; and a second mesa part 46 formed on the second principal surface 23. On the side surface of the first mesa part 41, a curved surface connected to the apex surface 41a of the first mesa part 41 is formed, and on the side surface of the second mesa part 46, a curved surface connected to the apex surface 46a of the second mesa part 46 is formed.

Description

  The present invention relates to a piezoelectric vibrating piece, a piezoelectric vibrator, and a method for manufacturing a piezoelectric vibrating piece.

  In the piezoelectric vibrating piece formed by AT cut, when the piezoelectric vibrating piece is reduced in size and frequency is reduced, vibration oscillated by the excitation unit formed in the center easily propagates to the end of the piezoelectric vibrating piece. Therefore, a structure that efficiently confines vibration energy in the center is required. In order to confine the vibration energy of the main vibration due to the thickness shear vibration in the central portion of the piezoelectric vibrating piece, a so-called mesa-type piezoelectric vibrating piece having a thick and flat central portion is known. For example, in the piezoelectric vibrating piece described in Patent Document 1, the mesa portion is formed by wet etching. At this time, since the piezoelectric vibrating piece formed by the AT cut has crystal anisotropy, the side surface of the mesa portion formed by wet etching becomes a natural crystal plane having a specific inclination angle.

JP 2008-67345 A

However, in the piezoelectric vibrating piece described above, among the side surfaces of the mesa portion which is a natural crystal plane, the side surface formed by a crystal plane (R plane) other than the m plane is connected at an angle close to a right angle with respect to the top surface. Therefore, a sharp ridge line is formed at the connection portion between the top surface and the side surface of the mesa portion. As a result, the main vibration is reflected at the ridge line portion, so that spurious oscillation is generated and the vibration characteristics are deteriorated.
Furthermore, in the mesa-type piezoelectric vibrating piece, an energy confinement effect can be obtained by increasing the step height of the mesa portion, but if the step height of the mesa portion is increased while the side surface of the mesa portion is close to a right angle, the mesa portion itself is deformed. Increases and spurious oscillation occurs. For this reason, the step of the mesa portion cannot be increased, and the energy confinement effect is limited. As a result, since the crystal impedance (CI value) cannot be lowered, good vibration characteristics cannot be obtained.

  Accordingly, the present invention provides a piezoelectric vibrating piece having excellent vibration characteristics, a piezoelectric vibrator, and a method for manufacturing the piezoelectric vibrating piece.

In order to solve the above-described problem, a piezoelectric vibrating piece according to the present invention is a piezoelectric vibrating piece formed by AT cut and having a piezoelectric plate having a first main surface, a second main surface, and side surfaces, It has a mesa portion formed on at least one of the first main surface and the second main surface, and a curved surface connected to the top surface of the mesa portion is formed on a side surface of the mesa portion. And
According to the present invention, since the curved surface connected to the top surface of the mesa portion is formed on the side surface of the mesa portion, the top surface and the side surface are connected smoothly compared to the case where the side surface is formed of a slope. As a result, the ridge lines at the connecting portions on both sides become dull. Thereby, the reflection of the vibration in the connection part becomes small, and spurious oscillation is suppressed. Further, by forming a curved surface on the side surface of the mesa portion, deformation of the mesa portion itself is suppressed, and spurious oscillation is suppressed. Therefore, it becomes possible to increase the step of the mesa portion, and the energy confinement efficiency of the piezoelectric vibrating piece is improved. As a result, the CI value of the piezoelectric vibrating piece can be reduced. Therefore, a piezoelectric vibrating piece having excellent vibration characteristics can be obtained.

In the above piezoelectric vibrating piece, it is preferable that the curved surface is formed on all the side surfaces of the mesa portion.
According to this configuration, since the ridge lines of all the connecting portions between the top surface of the mesa portion and the side surface of the mesa portion become dull, spurious oscillation can be more reliably suppressed. Therefore, a piezoelectric vibrating piece with more excellent vibration characteristics can be obtained.

In the piezoelectric vibrating piece, the mesa portion includes a plurality of mesa step portions stacked in a staircase pattern, and at least one of the plurality of mesa step portions has a side surface of the mesa step portion. It is desirable that a curved surface connected to the top surface of the step portion is formed.
According to this configuration, since the side surface of the mesa portion gradually approaches the side surface of the piezoelectric plate, deformation of the mesa portion itself is reduced, and spurious oscillation is suppressed. For this reason, the step of the mesa portion can be increased, and the energy confinement efficiency can be further improved. Therefore, a piezoelectric vibrating piece with more excellent vibration characteristics can be obtained.

In the above-described piezoelectric vibrating piece, it is preferable that a curved surface connected to at least one of the first main surface and the second main surface is formed on a side surface of the piezoelectric plate.
According to this configuration, the side surface of the piezoelectric plate is smoothly connected to at least one of the first main surface and the second main surface, and the ridge lines at the connection portions on both surfaces are blunt. As a result, the reflection of vibration transmitted to the connecting portion without being sufficiently attenuated is reduced, and spurious oscillation is suppressed. Therefore, a piezoelectric vibrating piece with more excellent vibration characteristics can be obtained.

The piezoelectric vibrating piece includes a pair of mount electrodes formed on the second main surface and a second mesa portion formed on the second main surface, and the second mesa portion includes the first mesa portion. 2 The top surface of the second mesa portion has a plurality of side surfaces with different projection widths on the main surface, and sandwiches the first side surface with the smallest projection width among the plurality of side surfaces of the second mesa portion. It is desirable that at least one of the pair of mount electrodes is disposed on the opposite side of the first electrode.
According to this configuration, the area of the second main surface is increased in the region adjacent to the first side surface of the second mesa portion. By providing the mount electrode in that region, the distance from the mount electrode to the second mesa portion becomes longer. As a result, when mounting the piezoelectric vibrating piece, a margin can be ensured in the amount of wet spread of the mounting member used for fixing the piezoelectric vibrating piece and the package and the mounting position accuracy. Therefore, it is possible to prevent deterioration of the vibration characteristics due to the mounting member spreading from the mount electrode and adhering to the second mesa portion. Therefore, a piezoelectric vibrating piece with stable vibration characteristics can be obtained.

The piezoelectric vibrator of the present invention includes the above-described piezoelectric vibrating piece.
According to this configuration, since the piezoelectric vibrator includes the above-described piezoelectric vibrating piece having excellent vibration characteristics, a piezoelectric vibrator having excellent vibration characteristics can be obtained.

In the piezoelectric vibrator of the present invention, the above-described piezoelectric vibrating piece is enclosed in a package, and one of the pair of mount electrodes has the first side surface sandwiched between the top surfaces of the second mesa portions. The second mount electrode is disposed on the opposite side, and the other mount electrode of the pair of mount electrodes sandwiches a second side surface different from the first side surface among the plurality of side surfaces of the second mesa portion, and A mounting member that is disposed on the opposite side of the top surface of the unit, is disposed between the pair of mount electrodes of the piezoelectric vibrating piece and the package, and mounts the piezoelectric vibrating piece on the package. A contact area of the mounting member on the mount electrode is wider than a contact area of the mounting member on the other mount electrode.
According to this configuration, the area of the second main surface is widened in a region adjacent to the first side surface of the second mesa portion of the piezoelectric vibrating piece. Providing one of the pair of mount electrodes in the region increases the distance from the one mount electrode to the second mesa portion. Accordingly, when mounting the piezoelectric vibrating piece, when the mounting member is brought into contact with the mount electrode, the mounting member can be brought into wide contact with one of the mount electrodes to ensure the fixing strength of the piezoelectric vibrating piece. Since the mounting member of the minimum amount that can ensure the electrical connection with the package is brought into contact with the other mount electrode, the vibration characteristics are deteriorated due to the wetting spread of the mounting member on the other mount electrode. Can be prevented. Therefore, it is possible to obtain a piezoelectric vibrator including a piezoelectric vibrating piece with stable vibration characteristics.

A method for manufacturing a piezoelectric vibrating piece according to the present invention is a method for manufacturing a piezoelectric vibrating piece having a piezoelectric plate formed by AT cutting and having a first main surface, a second main surface, and a side surface. A step of forming a mesa mask having a mesa portion on at least one of the first main surface and the second main surface and forming a mesa mask having an outer shape pattern of the mesa portion on the surface of the wafer; and the wafer via the mesa mask. Etching to form an external pattern of the mesa unit, and wet etching the wafer to form a curved surface continuous with the top surface of the mesa unit on the side surface of the mesa unit. Features.
According to the present invention, by performing wet etching on the wafer on which the outer pattern of the mesa portion is formed, the ridge line between the top surface of the mesa portion and the side surface of the mesa portion is rounded, and the side surface of the mesa portion is curved. To change. Therefore, a piezoelectric vibrating piece having a curved mesa portion side surface continuous with the top surface of the mesa portion can be easily manufactured.

In the method for manufacturing the piezoelectric vibrating piece, a step of forming a curved surface connected to at least one of the first main surface and the second main surface on a side surface of the piezoelectric plate and forming an outer pattern of the mesa portion And in at least one of the steps of forming a curved surface on the side surface of the mesa portion, the wafer is wet-etched to form at least one of the first main surface and the second main surface on the side surface of the piezoelectric plate. A curved surface connected to one side is formed.
According to this method, the curved surface can be formed on the side surface of the piezoelectric plate simultaneously with at least one of the outer shape formation of the mesa portion and the curved surface formation on the side surface of the mesa portion. Therefore, a curved surface connected to at least one of the first main surface and the second main surface can be easily formed on the side surface of the piezoelectric plate without adding a special process.

In the above-described method for manufacturing a piezoelectric vibrating piece, the mesa portion has a plurality of mesa step portions stacked in a staircase pattern, and the plurality of mesa step portions are arranged inside the thickness direction of the piezoelectric plate. A first mesa step portion formed and a second mesa step portion disposed outside the piezoelectric plate in the thickness direction, forming the mesa mask, and forming an outer pattern of the mesa portion In the step of forming the first mesa step portion and the second mesa step portion and forming the curved surface on the side surface of the mesa portion, the first mesa step portion is formed on the side surface of the first mesa step portion. The step of forming a curved surface continuous with the top surface of the mesa step portion and forming the curved surface on the side surface of the first mesa step portion includes wet etching the wafer in the step of forming the outer shape pattern of the second mesa step portion. It is characterized by that.
According to this method, simultaneously with the formation of the second mesa step portion of the mesa portion, a curved surface continuous with the top surface of the first mesa step portion can be formed on the side surface of the first mesa step portion. Therefore, a curved surface connected to the top surface of the mesa step portion can be formed on the side surface of the mesa step portion without adding a special process to the piezoelectric vibrating piece having the mesa portion including a plurality of step portions.

  According to the piezoelectric vibrating piece of the present invention, the side surface of the mesa portion is formed with a curved surface that is continuous with the top surface of the mesa portion. Are smoothly connected, and the ridge lines at the connecting portions on both sides become dull. Thereby, the reflection of the vibration in the connection part becomes small, and spurious oscillation is suppressed. Further, by forming a curved surface on the side surface of the mesa portion, deformation of the mesa portion itself is suppressed, and spurious oscillation is suppressed. Therefore, it becomes possible to increase the step of the mesa portion, and the energy confinement efficiency of the piezoelectric vibrating piece is improved. As a result, the CI value of the piezoelectric vibrating piece can be reduced. Therefore, a piezoelectric vibrating piece having excellent vibration characteristics can be obtained.

  According to the method of manufacturing a piezoelectric vibrating piece of the present invention, by performing wet etching on the wafer on which the outer pattern of the mesa portion is formed, the ridge line between the top surface of the mesa portion and the side surface of the mesa portion is rounded, The side surface of the mesa portion changes to a curved surface. Therefore, a piezoelectric vibrating piece having a curved mesa portion side surface continuous with the top surface of the mesa portion can be easily manufactured.

FIG. 3 is a plan view of the piezoelectric vibrating piece according to the first embodiment. It is a side view of the piezoelectric vibrating piece according to the first embodiment. It is an exploded perspective view showing the piezoelectric vibrator of the first embodiment. It is explanatory drawing of the piezoelectric vibrator which concerns on 1st Embodiment, and is sectional drawing in the IV-IV line of FIG. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 1st Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 1st Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 1st Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 1st Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 1st Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 1st Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 1st Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 1st Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 1st Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 1st Embodiment. It is a bottom view of a piezoelectric vibrating piece according to a first modification of the first embodiment. FIG. 16 is an explanatory diagram of a piezoelectric vibrator according to a first modification of the first embodiment, and is a cross-sectional view showing a cross section along a cut surface passing through the XVI-XVI line of FIG. 15. It is a top view of the piezoelectric vibrating piece according to the second embodiment. FIG. 18 is an explanatory diagram of a piezoelectric vibrating piece according to a second embodiment, and is a cross-sectional view taken along line XVIII-XVIII in FIG. 17. FIG. 18 is an explanatory diagram of a piezoelectric vibrating piece according to a second embodiment, and is a cross-sectional view taken along line XIX-XIX in FIG. 17. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 2nd Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 2nd Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 2nd Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 2nd Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 2nd Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 2nd Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 2nd Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 2nd Embodiment. FIG. 6 is a plan view of a piezoelectric vibrating piece according to a third embodiment. It is a side view of the piezoelectric vibrating piece according to the third embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 3rd Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 3rd Embodiment. It is process drawing explaining the manufacturing method of the piezoelectric vibrating piece which concerns on 3rd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In describing the configuration of each figure, an XY′Z ′ coordinate system is used. Each axis in the XY′Z ′ coordinate system has the following relationship with the crystal axis of crystal described later. That is, the X axis is an electrical axis, the Z ′ axis is an axis inclined by 35 degrees and 15 minutes around the X axis with respect to the Z axis, which is an optical axis, and the Y ′ axis is orthogonal to the X axis and the Z ′ axis. It is an axis to do. In the X direction, the Y ′ direction, and the Z ′ direction, the arrow direction in FIG.

(First Embodiment, Piezoelectric Vibrating Piece and Piezoelectric Vibrator)
First, the piezoelectric vibrating piece and the piezoelectric vibrator of the first embodiment will be described.
FIG. 3 is an exploded perspective view showing the piezoelectric vibrator of the first embodiment.

  As shown in FIG. 3, the piezoelectric vibrator 1 of this embodiment is formed in a box shape in which a base substrate 3 and a lid substrate 5 are laminated in two layers, and the piezoelectric vibrating piece 10 is placed in an internal cavity 7. Is mounted.

The piezoelectric vibrating piece 10 includes a piezoelectric plate 20 and an electrode film 50 formed on the piezoelectric plate 20. The electrode film 50 has a pair of mount electrodes 55 formed on the second main surface 23.
The piezoelectric vibrating piece 10 is mounted on the upper surface 3a on the base substrate 3 using a mounting member such as a conductive adhesive. More specifically, a pair of mount electrodes 55 formed on the piezoelectric vibrating piece 10 is mounted on the pair of inner electrodes 8 formed on the upper surface 3 a of the base substrate 3 via the mounting member 9.
Thereby, the piezoelectric vibrating piece 10 is mechanically held on the upper surface 3a of the base substrate 3, and the inner electrode 8 and the mount electrode 55 are electrically connected to each other.

FIG. 1 is a plan view of the piezoelectric vibrating piece according to the first embodiment, and FIG. 2 is a side view.
As shown in FIGS. 1 and 2, the piezoelectric vibrating piece 10 of the present embodiment is formed by AT cut, and has a piezoelectric plate 20 having a first main surface 21, a second main surface 23, and a side surface 25. The resonator element has a mesa portion 40 formed on at least one of the first main surface 21 and the second main surface 23, and a curved surface connected to the top surface of the mesa portion 40 is formed on a side surface of the mesa portion 40. Is formed. In this application, when expressing the connection state between a flat surface and a curved surface, when the contact point between the curved surface and its tangent is brought close to the connection portion between the curved surface and the flat surface, the state in which the inclination of the tangent coincides with the inclination of the plane is expressed as `` It is expressed as “continuous”, and a state where the inclination of the tangent approximates the inclination of the plane is expressed as “continuous”. That is, “continuous” includes “continuous”.

The piezoelectric vibrating piece 10 is formed by AT cut and includes a piezoelectric plate 20 having a first main surface 21, a second main surface 23, and a side surface 25.
The piezoelectric plate 20 is formed into a rectangular plate shape having a predetermined thickness by AT cut from artificial quartz crystal processed by lumbar processing. The AT cut is 35 degrees around the X axis with respect to the Z axis among the three crystal axes of the electric axis (X axis), the mechanical axis (Y axis), and the optical axis (Z axis), which are crystal axes of artificial quartz. This is a processing method of cutting in a direction inclined by 15 minutes (Z′-axis direction). The piezoelectric vibrating piece 10 having the piezoelectric plate 20 cut out by the AT cut has an advantage that the frequency temperature characteristic is stable, the structure and shape are simple and easy to process, and the CI value is low. The piezoelectric plate 20 of this embodiment is formed so that the length in the Z ′ direction is longer than the length in the X direction.

The piezoelectric plate 20 is formed on a first main surface 21 that is parallel to the XZ ′ plane and formed on the + Y ′ direction side, a second main surface 23 that is formed on the −Y ′ direction side, and four outer sides. And has side surfaces 25.
The side surface 25 includes a first side surface 26 formed on the side on the + Z ′ direction side, a second side surface 27 formed on the side on the −Z ′ direction side, and the + X direction side among the four outer peripheral sides of the piezoelectric plate 20. And a fourth side surface 29 formed on the side on the −X direction side.

The piezoelectric vibrating piece 10 includes a first excitation electrode 51 formed on the first main surface 21 and a second excitation electrode 53 formed on the second main surface 23.
The first excitation electrode 51 is rectangular when viewed in the Y ′ direction, and is formed at the center of the first main surface 21. The second excitation electrode 53 is rectangular when viewed in the Y ′ direction, and is formed at the center position of the second main surface 23. The second excitation electrode 53 is formed so as to overlap the first excitation electrode 51 when viewed in the Y ′ direction.

Further, the piezoelectric vibrating piece 10 includes a pair of mount electrodes 55 formed on the second main surface 23 and connected to the first excitation electrode 51 and the second excitation electrode 53.
The pair of mount electrodes 55 includes a first mount electrode 55a and a second mount electrode 55b. The first mount electrode 55 a is formed in a rectangular shape when viewed in the Y ′ direction, and is provided at a corner of the second main surface 23 on the + X side and the −Z ′ side so as not to overlap the second excitation electrode 53. ing. The first mount electrode 55a is formed on the first main surface 21 via the first connection portion 61 formed on at least one of the + X side end portion and the −Z ′ side end portion of the piezoelectric plate 20. The first mount back electrode 65 is connected. The first mount back electrode 65 is formed so as to overlap the first mount electrode 55 a when viewed in the Y ′ direction, and is connected to the first excitation electrode 51 via the first routing wiring 57.

  The second mount electrode 55 b is formed in a rectangular shape as viewed in the Y ′ direction, and is provided at a corner of the second main surface 23 on the −X side and the −Z ′ side so as not to overlap the second excitation electrode 53. It has been. The second mount electrode 55 b is connected to the second excitation electrode 53 via the second routing wiring 59. Further, the second mount electrode 55b is formed on the first main surface 21 via the second connection portion 63 formed on at least one of the −X side end and the −Z ′ side end of the piezoelectric plate 20. The second mount back electrode 67 is connected to the formed second mount back electrode 67. The second mount back electrode 67 is formed so as to overlap the second mount electrode 55b when viewed in the Y ′ direction.

  The excitation electrode, mount electrode, routing wiring, mount back electrode, and connecting portion described above are laminated with a single layer film of metal such as gold, or a metal such as chromium as an underlayer and a metal such as gold as an upper layer. It is formed of a film or the like.

The piezoelectric vibrating piece 10 has a mesa portion 40 formed on at least one of the first main surface 21 and the second main surface 23. In the present embodiment, the first mesa portion 41 is formed on the first main surface 21, and the second mesa portion 46 is formed on the second main surface 23.
The first mesa portion 41 is formed in a rectangular shape as viewed in the Y ′ direction. The first mesa portion 41 is a central portion of the first main surface 21 and is formed at a position that does not overlap the first mount back electrode 65 and the second mount back electrode 67. The top surface 41 a of the first mesa portion 41 is formed in a planar shape parallel to the first main surface 21. A first excitation electrode 51 is formed on the top surface 41 a of the first mesa portion 41.

  The second mesa portion 46 is formed in a rectangular shape as viewed in the Y ′ direction. The second mesa portion 46 is formed in a central portion of the second main surface 23 and at a position that does not overlap the first mount electrode 55a and the second mount electrode 55b. The top surface 46 a of the second mesa portion 46 is formed in a planar shape parallel to the second main surface 23. A second excitation electrode 53 is formed on the top surface 46 a of the second mesa portion 46.

(Mesa side)
A curved surface continuous with the top surface of the mesa unit 40 is formed on the side surface of the mesa unit 40. In the present embodiment, curved surfaces continuous to the top surface 41a are formed on all side surfaces 41b to 41e of the first mesa portion 41, and curved surfaces continuous to the top surface 46a are formed on all side surfaces 46b to 46e of the second mesa portion 46. Is formed.
The first mesa portion 41 includes a first side surface 41b formed on the + Z ′ direction side, a second side surface 41c formed on the −Z ′ direction side, a third side surface 41d formed on the + X direction side, And a fourth side surface 41e formed on the X direction side.

  The first side surface 41b of the first mesa portion 41 is formed with a curved surface based on the R plane of the quartz crystal having an elevation angle with respect to the main surface of about 87 degrees. Specifically, the connection portion between the first side surface 41b formed in a planar shape by the R surface and the top surface 41a of the first mesa portion 41 is processed to be rounded by wet etching described later. A curved surface is formed on the first side surface 41b. That is, the first side surface 41 b is inclined in the (+ Y ′, −Z ′) direction from the connection portion with the first main surface 21, and is connected to the end portion on the + Z ′ direction side of the top surface 41 a of the first mesa portion 41. ing. The first side surface 41b is formed of a curved surface that is convex in the (+ Y ′, + Z ′) direction. The first side surface 41b is formed uniformly in the X direction. Since the first side surface 41b is formed by a curved surface that continues to the top surface 41a, the ridge line at the connecting portion 42b between the first side surface 41b and the top surface 41a is blunt. In the present embodiment, since the first side surface 41b and the top surface 41a are continuous, there is no ridgeline.

  The second side surface 41c of the first mesa portion 41 is formed with a curved surface mainly based on the m-plane of quartz crystal having an elevation angle with respect to the main surface of about 30 degrees. Specifically, the connection portion between the second side surface 41c formed in a planar shape by the m-plane (and the r-plane) and the top surface 41a of the first mesa portion 41 is rounded by wet etching described later. By processing, a curved surface is formed on the second side surface 41c. That is, the second side surface 41c is inclined in the (+ Y ′, + Z ′) direction from the connection portion with the first main surface 21, and is connected to the −Z ′ direction side end portion of the top surface 41a of the first mesa portion 41. ing. The second side surface 41c is formed of a curved surface that is convex in the (+ Y ′, −Z ′) direction. The second side surface 41c is formed uniformly in the X direction. Since the second side surface 41c is formed by a curved surface that continues to the top surface 41a, the ridge line at the connection portion 42c between the second side surface 41c and the top surface 41a is blunt.

  The third side surface 41d of the first mesa portion 41 is formed with a curved surface based on a natural crystal plane other than the m-plane and the R-plane of the crystal crystal having an elevation angle with respect to the main surface of 30 degrees or more and less than 87 degrees. Specifically, the connection portion between the third side surface 41d formed in a planar shape by a natural crystal plane other than the m-plane and the R-plane and the top surface 41a of the first mesa portion 41 is rounded by wet etching described later. By processing so as to be tinged, a curved surface is formed on the third side surface 41d. That is, the third side surface 41d is inclined in the (−X, + Y ′) direction from the connection portion with the first main surface 21, and is connected to the + X direction side end portion of the top surface 41a of the first mesa portion 41. . The third side surface 41d is formed of a curved surface that is convex in the (+ X, + Y ′) direction. The third side surface 41d is uniformly formed in the Z ′ direction. Since the third side surface 41d is formed of a curved surface that continues to the top surface 41a, the ridge line at the connection portion 42d between the third side surface 41d and the top surface 41a is blunt.

  The fourth side surface 41e of the first mesa portion 41 is formed with a curved surface based on a natural crystal plane other than the m-plane and the R-plane of the quartz crystal having an elevation angle with respect to the main surface of 30 degrees or more and less than 87 degrees. Specifically, the connection portion between the fourth side surface 41e formed in a planar shape by a natural crystal plane other than the m-plane and the R-plane and the top surface 41a of the first mesa portion 41 is rounded by wet etching described later. By processing so as to be tinged, a curved surface is formed on the fourth side surface 41e. That is, the fourth side surface 41 e is inclined in the (+ X, + Y ′) direction from the connection portion with the first main surface 21 and is connected to the end portion on the −X direction side of the top surface 41 a of the first mesa portion 41. . The fourth side surface 41e is formed of a curved surface that is convex in the (−X, + Y ′) direction. The fourth side surface 41e is formed uniformly in the Z ′ direction. Since the fourth side surface 41e is formed by a curved surface that continues to the top surface 41a, the ridge line at the connection portion 42e between the fourth side surface 41e and the top surface 41a is blunt.

By the way, in the conventional piezoelectric vibrating piece, all the side surfaces of the mesa portion are formed in a planar shape by the natural crystal plane of the quartz crystal. For this reason, ridge lines are formed at all connecting portions between the top surface and the side surfaces of the mesa portion. In particular, since the ridge line of the connecting portion between the top surface of the mesa portion and the side surface formed by the R surface is sharp, reflection of vibration becomes large at the connecting portion, and spurious oscillation occurs.
On the other hand, the top surface of the first mesa portion 41 is formed by forming a curved surface continuous with the top surface 41a on all the side surfaces 41b to 41e of the first mesa portion 41 as in the present embodiment shown in FIGS. All the ridgelines in the connecting portions 42b to 42e between 41a and the side surfaces 41b to 41e become dull. In particular, since the ridge line of the connection portion 42b with the first side surface 41b formed on the R surface, which is a problem in the conventional structure, becomes dull, reflection of vibration at the connection portion 42b is reduced, and spurious oscillation is suppressed. In addition, since the ridge lines of the other connection portions 42c to 42e are also dull, spurious oscillation that occurs in the connection portions 42c to 42e is suppressed.

  Further, by forming a curved surface continuous with the top surface 41a on all the side surfaces 41b to 41e of the first mesa portion 41, the cross-sectional shape of the first mesa portion 41 becomes a shape that tapers in the + Y ′ direction. Therefore, compared to the conventional piezoelectric vibrating piece in which the side surface of the mesa portion is formed at an angle close to a right angle with respect to the main surface, the deformation amount of the mesa portion itself is reduced, and spurious oscillation is suppressed. Therefore, the step of the first mesa portion 41 can be increased, and the energy confinement efficiency is improved. Therefore, the CI value can be reduced.

  The second mesa unit 46 includes a first side surface 46b formed on the −Z ′ direction side, a second side surface 46c formed on the + Z ′ direction side, a third side surface 46d formed on the −X direction side, And a fourth side surface 46e formed on the + X direction side.

  The first side surface 46 b of the second mesa portion 46 is inclined in the (−Y ′, + Z ′) direction from the connection portion with the second main surface 23, and is on the −Z ′ direction side of the top surface 46 a of the second mesa portion 46. It is connected to the end. The first side surface 46 b is formed in the same manner as the first side surface 41 b of the first mesa portion 41.

  The second side surface 46 c of the second mesa portion 46 is inclined in the (−Y ′, −Z ′) direction from the connection portion with the second main surface 23, and the + Z ′ direction side of the top surface 46 a of the second mesa portion 46. It is connected to the end. The second side surface 46 c is formed in the same manner as the second side surface 41 c of the first mesa portion 41.

  The third side surface 46 d of the second mesa portion 46 is inclined in the (+ X, −Y ′) direction from the connection portion with the second main surface 23, and is the end on the −X direction side of the top surface 46 a of the second mesa portion 46. Connected to the department. The third side surface 46d is formed in the same manner as the third side surface 41d of the first mesa portion 41.

  The fourth side surface 46e of the second mesa portion 46 is inclined in the (−X, −Y ′) direction from the connection portion with the second main surface 23, and is the end on the + X direction side of the top surface 46a of the second mesa portion 46. Connected to the department. The fourth side surface 46 e is formed in the same manner as the fourth side surface 41 e of the first mesa portion 41.

  In this way, by forming curved surfaces connected to the top surface 46a on all the side surfaces 46b to 46e of the second mesa portion 46, spurious oscillation is suppressed for the same reason as the first mesa portion 41, and the CI value is reduced. Can be reduced.

  Furthermore, in the present embodiment, the first routing wiring 57 and the second routing wiring 59 pass through the side surface on which the curved surface connected to the top surface of the mesa portion 40 is formed. Thereby, it is possible to prevent disconnection of the routing wiring due to passing over a sharp ridge line, which is likely to occur at the connecting portion between the side surface formed on the R surface and the top surface, in the conventional piezoelectric vibrating piece.

FIG. 4 is an explanatory diagram of the piezoelectric vibrator according to the first embodiment, and is a cross-sectional view taken along the line IV-IV in FIG. 3.
In the present embodiment, the mount electrode 55 is formed in a region adjacent to the first side surface 46 b where the projection width onto the second main surface 23 is the smallest among the side surfaces 46 b to 46 e of the second mesa unit 46. Specifically, the mount electrode 55 is disposed in a region opposite to the top surface 46a of the second mesa portion with the first side surface 46b interposed therebetween. Since the first side surface 46b has a larger elevation angle with respect to the second main surface 23 than the other side surface, the projection width onto the second main surface 23 is smaller than the other side surface and is adjacent to the first side surface 46b in the second main surface 23. The area of the region is increased. Thereby, a wide distance from the mount electrode 55 to the second mesa unit 46 can be secured. Therefore, as shown in FIG. 4, when the mounting member 9 disposed on the inner electrode 8 is brought into contact with the mount electrode 55, the mounting member 9 is caused to be wet or spread by the mounting position or the mounting position is shifted. Adhering to the second mesa unit 46 can be prevented.

As described above, the piezoelectric vibrating piece 10 of the present embodiment is a piezoelectric vibrating piece including the piezoelectric plate 20 that is formed by AT cut and includes the first main surface 21, the second main surface 23, and the side surface 25. The mesa portion 40 is formed on at least one of the first main surface 21 and the second main surface 23, and a curved surface connected to the top surface of the mesa portion 40 is formed on the side surface of the mesa portion 40. It is characterized by.
According to this embodiment, since the curved surface connected to the top surface of the mesa unit 40 is formed on the side surface of the mesa unit 40, the top surface and the side surface are compared with the case where the side surface is formed of a slope. It is connected smoothly, and the ridgeline in the connection part of both surfaces becomes dull. Thereby, the reflection of the vibration in the connection part becomes small, and spurious oscillation is suppressed. Further, by forming a curved surface on the side surface of the mesa unit 40, deformation of the mesa unit 40 itself is suppressed, and spurious oscillation is suppressed. Therefore, it is possible to increase the level difference of the mesa unit 40, and the energy confinement efficiency of the piezoelectric vibrating piece 10 is improved. As a result, the CI value of the piezoelectric vibrating piece 10 can be reduced. Therefore, a piezoelectric vibrating piece having excellent vibration characteristics can be obtained.

Further, the piezoelectric vibrating piece 10 of the present embodiment is characterized in that curved surfaces are formed on all side surfaces of the mesa unit 40.
According to the present embodiment, since the ridge lines of all the connecting portions between the top surface of the mesa portion 40 and the side surface of the mesa portion 40 become dull, spurious oscillation can be more reliably suppressed. Therefore, a piezoelectric vibrating piece with more excellent vibration characteristics can be obtained.

Further, the piezoelectric vibrating piece 10 of the present embodiment has a pair of mount electrodes 55 formed on the second main surface 23 and a second mesa portion 46 formed on the second main surface 23, and the second The mesa unit 46 includes a plurality of side surfaces 46 b to 46 e having different projection widths on the second main surface 23. Of the pair of mount electrodes 55, on the opposite side of the top surface 46 a of the second mesa 46 across the first side 46 b having the smallest projection width among the plurality of side surfaces 46 b to 46 e of the second mesa 46. At least one of them is arranged.
According to the present embodiment, the area of the second main surface 23 is widened in the region adjacent to the first side surface 46 b of the second mesa unit 46. By providing the mount electrode 55 in that region, the distance from the mount electrode 55 to the second mesa portion 46 becomes longer. Thereby, when the piezoelectric vibrating piece 10 is mounted, a margin can be ensured in the wet spread amount and mounting position accuracy of the mounting member 9 used for fixing the piezoelectric vibrating piece 10 and the package. Therefore, it is possible to prevent the vibration characteristics from deteriorating due to the mounting member 9 spreading from the mount electrode 55 and adhering to the second mesa portion 46. Therefore, a piezoelectric vibrating piece with stable vibration characteristics can be obtained.

The piezoelectric vibrator 1 according to this embodiment includes a piezoelectric vibrating piece 10.
According to this embodiment, since the piezoelectric vibrator 1 includes the piezoelectric vibrating piece 10 having excellent vibration characteristics described above, a piezoelectric vibrator having excellent vibration characteristics can be obtained.

(First Embodiment, Manufacturing Method of Piezoelectric Vibrating Piece)
Next, a manufacturing method of the piezoelectric vibrating piece according to the first embodiment will be described.
5 to 14 are process diagrams illustrating the method for manufacturing the piezoelectric vibrating piece according to the first embodiment, and are cross-sectional views taken along a line VV in FIG. 1.

  In the method for manufacturing the piezoelectric vibrating piece 10 of this embodiment, the mesa portion 40 is first formed, and then the outer shape of the piezoelectric plate 20 is formed. Among them, the mesa unit 40 is formed by forming a mesa mask 81a having an outer pattern of the mesa unit 40 on the surface of the wafer S, and etching the wafer S through the mesa mask 81a to form an outer pattern of the mesa unit 40. And a curved surface forming step of forming a curved surface continuous with the top surface of the mesa unit 40 on the side surface of the mesa unit 40 by wet etching the wafer S.

  First, a rough Lambert stone crystal is AT-cut and lapped to a constant thickness and then roughly processed, and then the work-affected layer is removed by etching, followed by mirror polishing such as polishing. A wafer S is prepared.

(Mesa mask forming process)
Next, the mesa mask forming process will be described. As shown in FIG. 5, an etching protection film 81 and a photoresist film 83 are formed on both surfaces of the wafer S, respectively.
The etching protective film 81 has resistance to etching of the wafer S made of quartz described later. For example, a chromium (Cr) metal layer having a thickness of several tens of nm and a gold (Au) metal layer having a thickness of several tens of nm are sequentially laminated.
In this step, first, an etching protective film 81 is formed on the front and back main surfaces of the wafer S by a sputtering method, a vapor deposition method, or the like.

Next, a resist material is applied on the etching protection film 81 by a spin coating method or the like to form a photoresist film 83.
As the resist material used in the present embodiment, a rubber negative resist mainly composed of cyclized rubber (for example, cyclized isoprene) is preferably used. The rubber negative resist is refined by dissolving cyclized rubber in an organic solvent, adding a bisazide photosensitizer, filtering, and removing impurities.

Next, as shown in FIGS. 6 and 7, a mesa mask 81 a having an outer pattern of the mesa portion is formed on the surface of the wafer S.
Specifically, first, one surface of the wafer S on which the etching protective film 81 and the photoresist film 83 are formed is exposed using a photomask on which an outer pattern of the mesa portion is formed. Similarly, the other surface of the wafer S is exposed using a photomask on which an outline pattern of the mesa portion is formed. Then, the photoresist film 83 formed on both surfaces of the wafer S is collectively developed. As a result, as shown in FIG. 6, a mesa portion outer shape pattern 83 a is formed on the photoresist film 83 formed on both surfaces of the wafer S.

Next, the etching protection film 81 formed on both surfaces of the wafer S is etched using the photoresist film 83 on which the outer shape pattern 83a of the mesa portion is formed as a mask, and the unmasked etching protection film 81 is selectively used. To remove. As a result, as shown in FIG. 7, mesa masks 81a having an outer shape pattern of the mesa portion are formed on both surfaces of the wafer S.
For the etching process of the etching protection film 81, a wet etching method in which the wafer S on which the etching protection film 81 and the photoresist film 83 are formed is immersed in a chemical solution can be used. For example, when the etching protection film 81 is made of gold (Au), etching can be performed using iodine as a chemical solution.

(Mesa formation process)
Next, the mesa forming process will be described. As shown in FIG. 8, the wafer S is etched through the mesa mask 81a to form an external pattern of the mesa unit 40.
The etching process of the wafer S can use a wet etching method in which the wafer S on which the mesa mask 81a is formed is immersed in a chemical solution. For example, etching can be performed using hydrofluoric acid as a chemical solution, and the etching time is about 30 minutes. Thereby, the external pattern of the mesa part 40 is formed. At this time, the natural crystal plane of the quartz crystal appears on the side surface of the mesa unit 40.

  Next, as shown in FIG. 9, the etching protection film 81 and the photoresist film 83 are removed. Thereby, the mesa part 40 will be in the state which the top surface and the side surface were exposed. The removal of the photoresist film 83 may be performed after the etching processing of the etching protective film 81 described above (before the mesa formation step).

(Curved surface forming process)
Next, the curved surface forming process will be described. As shown in FIG. 10, the wafer S is wet-etched to form a curved surface continuous with the top surface of the mesa unit 40 on the side surface of the mesa unit 40.
This wet etching process can be performed in the same manner as the wet etching process for forming the outline pattern of the mesa 40 described above. At this time, the etching time is about 30 minutes, for example.

  As described above, when wet etching is performed in a state where the mask in the vicinity of the connection portion between the top surface and the side surface of the mesa unit 40 is removed, the ridge line between the top surface and the side surface is etched so that the side surface has a convex curved surface shape. To change. Note that due to the etching anisotropy of the quartz crystal, the progress of the etching of the connecting portions between the side surfaces 41c, 46c formed on the m-plane and the top surface is slower than that of the other connecting portions. Therefore, the curved surface formed at the connection portion between the side surfaces 41c, 46c formed on the m-plane and the top surface is formed so that the area ratio with respect to the side surface on which the curved surface is formed is smaller than the other connection portions. Is done.

(Outline mask formation process)
Next, the outer shape mask forming process will be described. As shown in FIG. 11, an etching protection film 91 and a photoresist film 93 are formed on both surfaces of the wafer S on which the mesa portion 40 is formed. The material and forming method of the etching protective film 91 and the photoresist film 93 are the same as those of the etching protective film 81 and the photoresist film 83 in the mesa mask forming process.

Next, as shown in FIG. 12, an outer shape mask 91 a having an outer shape pattern of the piezoelectric plate 20 is formed on the surface of the wafer S.
Specifically, first, one surface of the wafer S on which the etching protection film 91 and the photoresist film 93 are formed is exposed using a photomask on which the outer shape pattern of the piezoelectric plate 20 is formed. Similarly, the other surface of the wafer S is exposed using a photomask on which the outer shape pattern of the piezoelectric plate 20 is formed. Then, the photoresist films 93 formed on both surfaces of the wafer S are collectively developed. Thus, the outer shape pattern 93a of the piezoelectric plate 20 is formed on the photoresist film 93 formed on both surfaces of the wafer S.
Next, the etching protection film 91 formed on both surfaces of the wafer S is etched using the photoresist film 93 on which the outer shape pattern 93a of the piezoelectric plate 20 is formed as a mask, and the unmasked etching protection film 91 is selected. To remove. As a result, as shown in FIG. 12, the outer shape mask 91a having the outer shape pattern of the piezoelectric plate 20 is formed on both surfaces of the wafer S. Etching of the etching protective film 91 is performed in the same manner as the etching protective film 81 in the mesa mask forming process.

(Outline forming process)
Next, the outer shape forming process will be described. As shown in FIG. 13, the wafer S is wet-etched through the outer shape mask 91a, and the outer shape pattern of the piezoelectric plate 20 is formed.
For the etching process of the wafer S, a wet etching method in which the wafer S on which the outer shape mask 91a is formed is immersed in a chemical solution can be used. Similar to the mesa formation step, for example, etching can be performed using hydrofluoric acid as a chemical solution. The etching time is about 3 hours. Thereby, the piezoelectric plate 20 is formed.

  Next, as shown in FIG. 14, the etching protection film 91 and the photoresist film 93 are removed. Thereby, the piezoelectric plate 20 having the mesa portion 40 with the curved surface formed on the side surface is obtained. The removal of the photoresist film 93 may be performed after the etching processing of the etching protective film 91 described above (before the outer shape forming step).

  Finally, the piezoelectric vibrating piece 10 is obtained by forming the excitation electrode, the mount electrode, the routing wiring, the mount back electrode, and the connection portion on the surface of the piezoelectric plate 20.

As described above, in the method of manufacturing the piezoelectric vibrating piece 10 according to the present embodiment, the mesa mask forming step of forming the mesa mask 81a having the outer pattern of the mesa unit 40 on the surface of the wafer S, and the wafer S are etched through the mesa mask 81a. A mesa forming step of forming an outer shape pattern of the mesa unit 40, and a curved surface forming step of forming a curved surface connected to the top surface of the mesa unit 40 on the side surface of the mesa unit 40 by wet etching the wafer S. It is characterized by that.
According to the present embodiment, by performing wet etching on the wafer S on which the outer shape pattern of the mesa unit 40 is formed, the ridge line between the top surface of the mesa unit 40 and the side surface of the mesa unit 40 is rounded. The side surface of 40 changes into a curved surface shape. Therefore, a piezoelectric vibrating piece having a curved mesa portion side surface continuous with the top surface of the mesa portion can be easily manufactured.

(First Embodiment, First Modification, Piezoelectric Vibrating Piece and Piezoelectric Vibrator)
Next, a piezoelectric vibrating piece according to a first modification of the first embodiment will be described.
15 is a bottom view of the piezoelectric vibrating piece according to the first modification of the first embodiment, and FIG. 16 is an explanatory diagram of the piezoelectric vibrator according to the first modification of the first embodiment. It is sectional drawing which shows the cross section along the cut surface which passes through the XVI-XVI line.

  In the first embodiment shown in FIG. 1, both the pair of mount electrodes 55 are formed in the vicinity of the first side surface 46 b of the second mesa unit 46. On the other hand, the first modification shown in FIG. 15 differs in that only the second mount electrode 55b of the pair of mount electrodes 55 is formed in the vicinity of the first side surface 46b of the second mesa portion 46. ing. Detailed descriptions of portions having the same configurations as those of the first embodiment shown in FIGS. 1 and 2 are omitted.

As shown in FIG. 15, the second mount electrode 55 b includes the second side surface 46 b to 46 e of the second mesa portion 46 with the first side surface 46 b having the smallest projection width on the second main surface 23 interposed therebetween. The mesa portion 46 is disposed on the opposite side of the top surface 46a.
The second mount electrode 55 b is formed in a rectangular shape as viewed in the Y ′ direction, and is disposed along the outer periphery of the second main surface 23 on the −Z ′ direction side.

Further, the first mount electrode 55a is disposed on the opposite side of the top surface 46a of the second mesa portion 46 with the second side surface 46c different from the first side surface 46b among the side surfaces 46b to 46e of the second mesa portion 46 interposed therebetween. Has been.
The first mount electrode 55a is formed in a rectangular shape when viewed in the Y ′ direction, and is disposed along the outer periphery of the second main surface 23 on the + Z ′ direction side. The first mount electrode 55 a is connected to the first mount back electrode 65 formed on the first main surface 21 via the first connection portion 61 formed on the + Z ′ side end of the piezoelectric plate 20. ing. The first mount back electrode 65 is formed to overlap the first mount electrode 55a when viewed in the Y ′ direction.

As shown in FIG. 16, a piezoelectric vibrator 1a in which a piezoelectric vibrating piece 10a is sealed in a base substrate 3 (package) is disposed between a pair of mount electrodes 55 and the base substrate 3, and the piezoelectric vibrating piece 10a is attached to the base substrate. 3 has a pair of mounting members 9 to be fixed.
The pair of mounting members 9 includes a first mounting member 9a and a second mounting member 9b. The first mounting member 9a connects the inner electrode 8a and the first mount electrode 55a. The second mounting member 9b connects the inner electrode 8b and the second mount electrode 55b.

The contact area of the second mounting member 9b on the second mount electrode 55b is larger than the contact area of the first mounting member 9a on the first mount electrode 55a.
The second mounting member 9b is disposed on the inner electrode 8 so as to have a larger volume than the first mounting member 9a. The amount of the second mounting member 9b is an amount capable of ensuring the fixing strength of the piezoelectric vibrating piece 10a alone. The amount of the first mounting member 9a is an amount that can secure at least electrical connection between the inner electrode 8a and the first mount electrode 55a.

  The second mount electrode 55b is disposed in a region adjacent to the first side surface 46b of the second mesa portion 46 having a narrow projection width on the second main surface 23, and a wide distance to the second mesa portion 46 is secured. ing. Therefore, when the second mounting member 9b is brought into contact with the second mount electrode 55b, it is possible to ensure the fixing strength of the piezoelectric vibrating piece 10a by making contact with a sufficiently large area. And since the 1st mounting member 9a should just contact the 1st mount electrode 55a with the minimum quantity which can ensure the electrical connection of the inner electrode 8a and the 1st mount electrode 55a, the 1st mounting member 9a It is possible to prevent deterioration of vibration characteristics of the piezoelectric vibrating piece 10a due to wetting and spreading.

As described above, in the piezoelectric vibrator 1a of this modification, the piezoelectric vibrating piece 10a is sealed in the package, and the second mount electrode 55b is opposite to the top surface 46a of the second mesa portion 46 with the first side surface 46b interposed therebetween. Placed on the side. The first mount electrode 55 a is disposed on the opposite side of the top surface 46 a of the second mesa 46 across the second side 46 c different from the first side 46 b among the plurality of side surfaces of the second mesa 46. The piezoelectric vibrator 1 a includes a pair of mounting members 9 that are disposed between the pair of mount electrodes 55 of the piezoelectric vibrating piece 10 a and the base substrate 3 and mount the piezoelectric vibrating piece 10 a on the base substrate 3. The contact area of the second mounting member 9b on the second mount electrode 55b is wider than the contact area of the first mounting member 9a on the first mount electrode 55a.
According to this modification, the area of the second main surface 23 is widened in the region adjacent to the first side surface 46b of the second mesa portion 46 of the piezoelectric vibrating piece 10a. By providing the second mount electrode 55b in that region, the distance from the second mount electrode 55b to the second mesa portion 46 becomes longer. Accordingly, when the piezoelectric vibrating piece 10a is mounted, when the second mounting member 9b is brought into contact with the second mount electrode 55b, the second mounting member 9b is brought into wide contact with the second mount electrode 55b to thereby make the piezoelectric vibrating piece 10a. Can be secured. Since a minimum amount of the mounting member 9 that can ensure electrical connection with the inner electrode 8a is brought into contact with the first mount electrode 55a, the first mounting member 9a on the first mount electrode 55a is contacted. It is possible to prevent the vibration characteristics from being deteriorated due to the spread of wetting. Therefore, it is possible to obtain a piezoelectric vibrator including a piezoelectric vibrating piece with stable vibration characteristics.

  In the present modification, the first mount electrode 55a is disposed in the vicinity of the second side face 46c of the second mesa portion 46, but may be disposed in the vicinity of the third side face 46d or the fourth side face 46e. However, if the first mount electrode 55a is disposed in the vicinity of the second side face 46c as in the present modification, the piezoelectric vibrating piece 10a is mounted at both ends in one direction, so that the piezoelectric vibrating piece 10a can be stably supported.

(Second Embodiment, Piezoelectric Vibrating Piece)
Next, the piezoelectric vibrating piece according to the second embodiment will be described.
FIG. 17 is a plan view of the piezoelectric vibrating piece according to the second embodiment. 18 is an explanatory diagram of the piezoelectric vibrating piece according to the second embodiment, and is a cross-sectional view taken along line XVIII-XVIII in FIG. FIG. 19 is an explanatory diagram of the piezoelectric vibrating piece according to the second embodiment, and is a cross-sectional view taken along line XIX-XIX in FIG.

  In the first embodiment shown in FIGS. 1 and 2, the side surface of the piezoelectric plate 20 is formed as a flat surface, but in the second embodiment shown in FIGS. 17 to 19, a curved surface is formed on the side surface of the piezoelectric plate 20. Is different. Detailed descriptions of portions having the same configurations as those of the first embodiment shown in FIGS. 1 and 2 are omitted.

  As shown in FIGS. 17 and 18, the first side surface 26 of the piezoelectric plate 20 is formed by a curved surface that is continuous with the first main surface 21. That is, the first side surface 26 is inclined in the (−Y ′, + Z ′) direction from the end portion on the + Z ′ direction side of the first main surface 21, and is connected to the end portion on the + Z ′ direction side of the second main surface 23. ing. The first side surface 26 is formed of a curved surface that is convex in the (+ Y ′, + Z ′) direction. The first side surface 26 is formed uniformly in the X direction. Since the first side surface 26 is formed by a curved surface continuous with the first main surface 21, the ridge line at the connection portion 21 a between the first side surface 26 and the first main surface 21 is dull. In the present embodiment, since the first side surface 26 and the first main surface 21 are continuous, there is no ridgeline.

By the way, the conventional piezoelectric vibrating piece is connected at an angle close to 90 degrees with respect to the main surface. That is, a sharp ridge line is formed at the connection portion between the side surface and both main surfaces. Therefore, when vibration is transmitted without being sufficiently attenuated to the end of the piezoelectric vibrating piece, the vibration is reflected at the connection portion between the side surface and both main surfaces, and spurious oscillation occurs.
On the other hand, by forming the first side surface 26 with a curved surface as in the present embodiment shown in FIGS. 17 and 18, the ridgeline of the connecting portion 21a becomes dull, and the first side surface 26 and the first main surface 21 or the second side surface are formed. Of the connecting portions with the main surface 23, the connecting portion having a sharp ridge line is only one portion of the connecting portion 23b. Thereby, spurious oscillation generated at the end portion of the piezoelectric vibrating piece 110 on the + Z ′ direction side is suppressed.

  The second side surface 27 is formed by a curved surface that continues to the second main surface 23. That is, the second side surface 27 is inclined in the (+ Y ′, −Z ′) direction from the end portion on the −Z ′ direction side of the second main surface 23, and is on the end portion on the −Z ′ direction side of the first main surface 21. Connected. The second side surface 27 is formed of a curved surface that is convex in the (−Y ′, −Z ′) direction. The second side surface 27 is formed uniformly in the X direction. Since the second side surface 27 is formed by a curved surface that continues to the second main surface 23, the ridge line at the connection portion 23 a between the second side surface 27 and the second main surface 23 is dull. In the present embodiment, since the second side surface 27 and the second main surface 23 are continuous, there is no ridgeline. As a result, among the connecting portions between the second side surface 27 and the first main surface 21 or the second main surface 23, the connecting portion having a sharp ridge line is only one portion of the connecting portion 21b, and for the same reason as the first side surface 26. The spurious oscillation generated at the end of the piezoelectric vibrating piece 110 on the −Z ′ direction side is suppressed.

  As shown in FIGS. 17 and 19, the third side surface 28 includes a first partial side surface 28 a continuous with the first main surface 21, a second partial side surface 28 b continuous with the second main surface 23, and a first partial side surface 28 a. And a third partial side surface 28c connecting the second partial side surface 28b.

  The first partial side surface 28a of the third side surface 28 is curved to be convex in the (+ X, + Y ′) direction while being inclined in the (+ X, −Y ′) direction from the end portion on the + X direction side of the first main surface 21. It is formed with a surface. The first partial side surface 28a is formed uniformly in the Z ′ direction. Since the first partial side surface 28 a is formed by a curved surface that continues to the first main surface 21, the ridge line at the connection portion 21 c between the first partial side surface 28 a and the first main surface 21 is blunt. In the present embodiment, since the first partial side surface 28a and the first main surface 21 are continuous, there is no ridgeline.

  The second partial side surface 28b of the third side surface 28 is curved to be convex in the (+ X, −Y ′) direction while being inclined in the (+ X, + Y ′) direction from the end portion on the + X direction side of the second main surface 23. It is formed with a surface. The second partial side surface 28b is uniformly formed in the Z ′ direction. Since the second partial side surface 28 b is formed by a curved surface continuous with the second main surface 23, the ridge line at the connection portion 23 c between the second partial side surface 28 b and the second main surface 23 is dull. In the present embodiment, since the second partial side surface 28b and the second main surface 23 are continuous, there is no ridgeline.

  The third partial side surface 28c of the third side surface 28 is a curved surface that is connected to the + X direction side end of the first partial side surface 28a and the + X direction side end of the second partial side surface 28b and is convex in the + X direction. Is formed. The third partial side surface 28c is formed uniformly in the Z ′ direction.

  By forming the third side surface 28 in this way, all the ridge lines of the third side surface 28 become dull, so that spurious oscillation that occurs at the end portion on the + X direction side of the piezoelectric vibrating piece 110 is suppressed.

  The fourth side surface 29 connects the first partial side surface 29a continuous with the first main surface 21, the second partial side surface 29b continuous with the second main surface 23, and the first partial side surface 29a and the second partial side surface 29b. And a three-part side surface 29c.

  The first partial side surface 29a of the fourth side surface 29 protrudes in the (−X, + Y ′) direction while inclining in the (−X, −Y ′) direction from the end portion on the −X direction side of the first main surface 21. It is formed with a curved surface. The first partial side surface 29a is uniformly formed in the Z ′ direction. Since the first partial side surface 29 a is formed by a curved surface that is continuous with the first main surface 21, the ridge line at the connection portion 21 d between the first partial side surface 29 a and the first main surface 21 is dull. In the present embodiment, since the first partial side surface 29a and the first main surface 21 are continuous, there is no ridgeline.

  The second partial side surface 29b of the fourth side surface 29 protrudes in the (−X, −Y ′) direction while inclining in the (−X, + Y ′) direction from the end portion of the second main surface 23 on the −X direction side. It is formed with a curved surface. The second partial side surface 29b is formed uniformly in the Z ′ direction. Since the second partial side surface 29b is formed by a curved surface continuous with the second main surface 23, the ridge line at the connection portion 23d between the second partial side surface 29b and the second main surface 23 is blunt. In the present embodiment, since the second partial side surface 29b and the second main surface 23 are continuous, there is no ridgeline.

  The third partial side surface 29c of the fourth side surface 29 is connected to the end portion on the −X direction side of the first partial side surface 29a and the end portion on the −X direction side of the second partial side surface 29b, and is convex in the −X direction. It is formed with a curved surface. The third partial side surface 29c is uniformly formed in the Z ′ direction.

  By forming the fourth side surface 29 in this manner, all the ridge lines of the fourth side surface 29 become dull, and thus spurious oscillation that occurs at the −X direction end of the piezoelectric vibrating piece 110 is suppressed.

The piezoelectric vibrating piece 110 according to this embodiment is characterized in that a curved surface connected to at least one of the first main surface 21 and the second main surface 23 is formed on the side surface of the piezoelectric plate 20.
According to the present embodiment, the side surface of the piezoelectric plate 20 is smoothly connected to at least one of the first main surface 21 and the second main surface 23, and the ridge lines at the connection portions on both surfaces become dull. As a result, the reflection of vibration transmitted to the connecting portion without being sufficiently attenuated is reduced, and spurious oscillation is suppressed. Therefore, a piezoelectric vibrating piece with more excellent vibration characteristics can be obtained.

(Second Embodiment, Manufacturing Method of Piezoelectric Vibrating Piece)
Next, a method for manufacturing the piezoelectric vibrating piece according to the second embodiment will be described.
20 to 27 are process diagrams illustrating the method for manufacturing the piezoelectric vibrating piece according to the second embodiment, and are cross-sectional views corresponding to FIG.

  In the method of manufacturing the piezoelectric vibrating piece 110 according to this embodiment, contrary to the first embodiment, the outer shape of the piezoelectric plate 20 is first formed, and then the mesa portion 40 is formed. In the formation of the mesa unit 40, in the mesa forming step for forming the outer shape pattern of the mesa unit 40 and the curved surface forming step for forming a curved surface on the side surface of the mesa unit 40, the side surface of the piezoelectric plate 20 is obtained by wet etching the wafer S. 25, a curved surface connected to at least one of the first main surface 21 and the second main surface 23 is formed.

  First, as in the first embodiment shown in FIG. 5, an etching protection film 191 and a photoresist film 193 are formed on both surfaces of the wafer S, respectively.

  Next, as shown in FIG. 20, an outer shape mask 191 a of the outer shape pattern of the piezoelectric plate 20 is formed on the surface of the wafer S. The etching protective film 191 and the photoresist film 193 are processed in the same manner as the outer shape mask forming process in the first embodiment.

  Next, as shown in FIG. 21, the wafer S is wet-etched through the outer shape mask 191a to form the outer shape pattern of the piezoelectric plate 20. Etching of the wafer S is performed in the same manner as the outer shape forming process in the first embodiment.

  Next, as shown in FIG. 22, the etching protection film 191 and the photoresist film 193 are removed. Thereby, the wafer S on which the outer shape pattern of the piezoelectric plate 20 is formed is obtained.

  Next, a mesa mask forming process is performed. As shown in FIG. 23, an etching protection film 181 and a photoresist film 183 are formed on both surfaces of the wafer S on which the outer shape pattern of the piezoelectric plate 20 is formed. The material and forming method of the etching protective film 181 and the photoresist film 183 are the same as those of the etching protective film 191 and the photoresist film 193 described above.

  Next, as shown in FIG. 24, a mesa mask 181 a having an outer shape pattern of the mesa portion is formed on the surface of the wafer S. The etching protective film 181 and the photoresist film 183 are processed in the same manner as the mesa mask forming process in the first embodiment. Note that the mesa mask 181a may be formed from the etching protection film 191 without removing the etching protection film 191 after the outer shape pattern of the piezoelectric plate 20 is formed.

  Next, a mesa forming process is performed. As shown in FIG. 25, the wafer S is wet-etched through the mesa mask 181a to form an external pattern of the mesa unit 40. Etching of the wafer S is performed in the same manner as the mesa forming process in the first embodiment. Thereby, the external shape of the mesa part 40 is formed. At this time, since the vicinity of the connection portion between the first main surface 21 and the second main surface 23 of the piezoelectric plate 20 and the side surface 25 is exposed, wet etching at the time of forming the outer shape of the mesa portion 40 causes the piezoelectric plate 20 to A curved surface is simultaneously formed on the side surface 25.

  Next, as shown in FIG. 26, the etching protection film 181 and the photoresist film 183 are removed. Thereby, the mesa part 40 will be in the state which the top surface and the side surface were exposed.

  Next, a curved surface forming step is performed. As shown in FIG. 27, the wafer S is wet-etched to form a curved surface continuous with the top surface of the mesa unit 40 on the side surface of the mesa unit 40. This wet etching process is performed in the same manner as the curved surface forming step in the first embodiment. At this time, since the vicinity of the connection portion between the first main surface 21 and the second main surface 23 of the piezoelectric plate 20 and the side surface 25 is exposed, the curved surface formed on the side surface 25 of the piezoelectric plate 20 is further etched. And the ridgeline in a connection part with a main surface becomes blunt.

  Finally, the excitation electrode, the mount electrode, the routing wiring, the mount back electrode, and the connection portion are formed on the surface of the piezoelectric plate 20, thereby forming a curved surface continuous with at least one of the first main surface 21 and the second main surface 23. The piezoelectric vibrating piece 110 having the formed side surface 25 is obtained.

  In this embodiment, the mesa mask forming step, the mesa forming step, and the curved surface forming step are performed after the outer shape pattern of the piezoelectric plate 20 is formed. However, after the mesa forming step (before the curved surface forming step), An external pattern may be formed. In this case, a curved surface is also formed on the side surface of the piezoelectric plate 20 in the curved surface forming step performed after forming the external pattern of the piezoelectric plate 20. However, as in the manufacturing method of this embodiment, by forming the outer shape pattern of the piezoelectric plate 20 before the mesa forming step, the curved surface formation of the side surface 25 of the piezoelectric plate 20 can be performed in two ways: a mesa forming step and a curved surface forming step. It can be performed in a process. Therefore, a curved surface can be more reliably formed on the side surface 25 of the piezoelectric plate 20.

As described above, in the method of manufacturing the piezoelectric vibrating piece 110 according to the present embodiment, the wafer S is wet-etched in the mesa forming process for forming the outer shape pattern of the mesa unit 40 and the curved surface forming process for forming a curved surface on the side surface of the mesa unit 40. As a result, a curved surface connected to at least one of the first main surface 21 and the second main surface 23 is formed on the side surface 25 of the piezoelectric plate 20.
According to this method, the curved surface can be formed on the side surface 25 of the piezoelectric plate 20 simultaneously with the formation of the outer shape of the mesa unit 40 and the curved surface formation on the side surface of the mesa unit. Therefore, a curved surface connected to at least one of the first main surface 21 and the second main surface 23 can be easily formed on the side surface 25 of the piezoelectric plate 20 without adding a special process.

(Third embodiment, piezoelectric vibrating piece)
Next, a piezoelectric vibrating piece according to a third embodiment will be described.
FIG. 28 is a plan view of the piezoelectric vibrating piece according to the third embodiment, and FIG. 29 is a side view.

  In the first embodiment shown in FIG. 1 and FIG. 2, the first mesa portion 41 and the second mesa portion 46 are each formed in one stage, but in the third embodiment shown in FIG. 28 and FIG. The mesa portion 241 and the second mesa portion 246 are different in that they are formed in a plurality of stages. Detailed descriptions of portions having the same configurations as those of the first embodiment shown in FIGS. 1 and 2 are omitted.

As shown in FIG. 28 and FIG. 29, the first mesa portion 241 is laminated in a staircase shape, and the first mesa step portion 243 arranged inside the thickness direction of the piezoelectric plate 20 and the thickness of the piezoelectric plate 20 are arranged. It has the 2nd mesa step part 244 arrange | positioned on the outer side of the vertical direction.
The first mesa step portion 243 of the first mesa portion 241 is formed on the first main surface 21. On all side surfaces of the first mesa step portion 243, a curved surface continuous with the top surface 243a of the first mesa step portion 243 is formed. The first mesa step portion 243 is formed in a shape that substantially matches the first mesa portion 41 in the piezoelectric vibrating piece 10 of the first embodiment.
The second mesa step portion 244 of the first mesa portion 241 is formed on the top surface 243 a of the first mesa step portion 243. All the side surfaces of the second mesa step portion 244 are formed by a plane that is a natural crystal plane of the crystal crystal. A first excitation electrode 51 is disposed on the top surface 244 a of the second mesa step 244.
By forming a curved surface on the side surface of the first mesa step portion 243, an effect similar to the suppression of spurious oscillation occurring at the connection portion between the side surface and the top surface of the mesa portion 40 in the first embodiment can be obtained. Note that by forming a curved surface also on the side surface of the second mesa step portion 244, spurious oscillation can be further suppressed.

  By forming the first mesa portion 241 in a stepped manner in this way, the side surface of the first mesa portion 241 approaches the side surface 25 of the piezoelectric plate 20 stepwise. Thereby, the deformation of the first mesa portion 241 itself is reduced, and spurious oscillation is suppressed. Therefore, the step of the first mesa unit 241 can be increased, and the energy confinement efficiency can be further improved.

  The second mesa portion 246 is formed in the same manner as the first mesa portion 241. By forming the second mesa portion 246 in a stepped manner in this manner, the energy confinement efficiency in the second mesa portion 246 can be further improved for the same reason as the first mesa portion 241.

The piezoelectric vibrating piece 210 of the present embodiment has a plurality of mesa step portions in which a first mesa portion 241 and a second mesa portion 246 are stacked in a step shape, and at least one mesa step portion among the plurality of mesa step portions. A curved surface connected to the top surface of the mesa step portion is formed on the side surface of the portion.
According to the present embodiment, since the side surfaces of the first mesa unit 241 and the second mesa unit 246 approach the side surface 25 of the piezoelectric plate 20 stepwise, the deformation of the mesa unit itself is reduced and spurious oscillation occurs. It is suppressed. For this reason, the step between the first mesa portion 241 and the second mesa portion 246 can be increased, and the energy confinement efficiency can be further improved. Therefore, a piezoelectric vibrating piece with more excellent vibration characteristics can be obtained.

  In the present embodiment, two mesa step portions are formed in the first mesa portion 241 and the second mesa portion 246, but three or more mesa step portions may be formed. Thereby, the deformation of the mesa step portion itself is further reduced, and spurious oscillation is further suppressed.

(Third Embodiment, Method for Manufacturing Piezoelectric Vibrating Piece)
Next, a method for manufacturing the piezoelectric vibrating piece according to the third embodiment will be described.
30 to 32 are process diagrams illustrating the method for manufacturing the piezoelectric vibrating piece according to the third embodiment, and are cross-sectional views taken along a line XXX-XXX in FIG. 28.

  In the method for manufacturing the piezoelectric vibrating piece 210 according to the present embodiment, the mesa mask forming step for forming the mesa mask and the mesa forming step for forming the outer shape pattern of the mesa portion are repeatedly performed, and the first mesa step portions 243 and 248 and the second mesa step portions 243 and 248 Mesa step portions 244 and 249 are formed. In the curved surface forming step of forming a curved surface on the side surface of the mesa portion, curved surfaces connected to the top surfaces 243a and 248a of the first mesa step portions 243 and 248 are formed on the side surfaces of the first mesa step portions 243 and 248. The step of forming curved surfaces on the side surfaces of the first mesa step portions 243 and 248 is performed by wet etching the wafer S in the step of forming the outer shape pattern of the second mesa step portions 244 and 249.

  First, in order to form the first mesa step portions 243 and 248, a first mesa mask forming step and a first mesa forming step are performed. The first mesa mask forming step and the first mesa forming step are the same as the mesa mask forming step and the mesa forming step of the first embodiment. Detailed description up to the first mesa forming step corresponding to FIG. 9 is omitted.

Next, in order to form the second mesa step portions 244 and 249, a second mesa mask forming step and a second mesa forming step are performed. The second mesa mask forming step and the second mesa forming step are the same as the mesa mask forming step and the mesa forming step of the first embodiment.
Specifically, as shown in FIG. 30, a second mesa mask forming step is performed, on the top surface 243 a of the first mesa step portion 243 of the first mesa portion 241 and the first mesa step portion of the second mesa portion 246. A mask 281a of the second mesa step portion is formed on the top surface 248a of 248.

  Next, as shown in FIG. 31, a second mesa formation step is performed, and the wafer S is wet-etched through the mask 281a of the second mesa step portions 244 and 249, whereby the second mesa step portions 244 and 249 are formed. Form an outer pattern. At this time, the mask 281a of the second mesa step portions 244 and 249 is not disposed in the vicinity of the connection portion between the top surface and the side surface of the first mesa step portions 243 and 248. That is, the vicinity of the connecting portion between the top surface and the side surface of the first mesa step portions 243 and 248 is exposed. Therefore, a curved surface continuous with the top surface 243a of the first mesa step portion 243 is formed on all side surfaces of the first mesa step portion 243 of the first mesa portion 241, and the first mesa step portion 248 of the second mesa portion 246 is formed. A curved surface continuous with the top surface 248a of the first mesa step 248 is formed on all the side surfaces.

  Next, as shown in FIG. 32, the etching protection film 281 and the photoresist film 283 are removed. It is possible to form three or more mesa step portions with respect to the mesa portion by repeatedly performing the above-described mesa mask forming step and mesa forming step. Even in this case, a curved surface can be formed on the side surface of the lower mesa step portion at the same time as the outer shape of the upper mesa step portion. If wet etching of the wafer S is added last, a curved surface can be formed on the side surface of the uppermost mesa step.

  Next, as in the first embodiment, the outer shape mask forming step and the outer shape forming step shown in FIGS. Finally, an excitation electrode, a mount electrode, a routing wiring, a mount back electrode, and a connection portion are formed on the surface of the piezoelectric plate 20, so that a piezoelectric element having a plurality of mesa step portions in which mesa portions are stacked in a staircase pattern. A vibrating piece 210 is obtained.

As described above, in the method of manufacturing the piezoelectric vibrating piece according to the present embodiment, the mesa mask forming process for forming the mesa mask and the mesa forming process for forming the external pattern of the mesa part are repeatedly performed, so that the first mesa step parts 243 and 248 are performed. And the 2nd mesa step part 244,249 is formed. In the curved surface forming step of forming a curved surface on the side surface of the mesa portion, a curved surface continuous with the top surfaces of the first mesa step portions 243 and 248 is formed on the side surfaces of the first mesa step portions 243 and 248. The step of forming curved surfaces on the side surfaces of the first mesa step portions 243 and 248 is performed by wet etching the wafer S in the step of forming the outer shape pattern of the second mesa step portions 244 and 249. To do.
According to this method, the first mesa step portions 243 and 248 are formed on the side surfaces of the first mesa step portions 243 and 248 simultaneously with the formation of the second mesa step portions 244 and 249 of the first mesa portion 241 and the second mesa portion 246. It is possible to form a curved surface that continues to the top surface of the. Therefore, a curved surface connected to the top surface of the mesa step portion can be formed on the side surface of the mesa step portion without adding a special process to the piezoelectric vibrating piece having the mesa portion including a plurality of step portions.

The present invention is not limited to the embodiment described above.
For example, in the piezoelectric vibrating piece of the above embodiment, the length in the Z ′ direction is longer than the length in the X direction, but the length in the X direction is longer than the length in the Z ′ direction. It may be formed.

  DESCRIPTION OF SYMBOLS 1, 1a ... Piezoelectric vibrator 9 ... Mounting member 10, 10a, 110, 210 ... Piezoelectric vibrating piece 20 ... Piezoelectric plate 21 ... First main surface 23 ... Second main surface 25 ... Side surface of piezoelectric plate 41, 241 ... First Mesa part (mesa part) 41a ... Top face of the first mesa part 41b ... First side face of the first mesa part (side face of the mesa part) 41c ... Second side face of the first mesa part (side face of the mesa part) 41d ... 3rd side surface of 1 mesa part (side surface of mesa part) 41e ... 4th side surface of 1st mesa part (side surface of mesa part) 46, 246 ... 2nd mesa part (mesa part) 46a ... Top surface of 2nd mesa part 46b ... 1st side surface of 2nd mesa part (side surface of mesa part) 46c ... 2nd side surface of 2nd mesa part (side surface of mesa part) 46d ... 3rd side surface of 2nd mesa part (side surface of mesa part) 46e ... Fourth side surface of second mesa portion (side surface of mesa portion) 55 ... Mount electrode 81 ... Mesa mask 243 248 ... first mesa step (mesa step) 243a, 248a ... top surface of the first mesa step (the top surface of the mesa step) 244,249 ... second mesa step (mesa step) S ... wafer

Claims (10)

A piezoelectric vibrating piece having a piezoelectric plate formed by AT cut and having a first main surface, a second main surface, and side surfaces,
A mesa portion formed on at least one of the first main surface and the second main surface;
A curved surface connected to the top surface of the mesa portion is formed on the side surface of the mesa portion.
A piezoelectric vibrating piece characterized by that. The piezoelectric vibrating piece according to claim 1,
The curved surface is formed on all the side surfaces of the mesa portion.
A piezoelectric vibrating piece characterized by that. The piezoelectric vibrating piece according to claim 1 or 2,
The mesa portion has a plurality of mesa step portions stacked in a staircase pattern,
A curved surface connected to a top surface of the mesa step portion is formed on a side surface of at least one of the plurality of mesa step portions.
A piezoelectric vibrating piece characterized by that. The piezoelectric vibrating piece according to any one of claims 1 to 3,
A curved surface connected to at least one of the first main surface and the second main surface is formed on a side surface of the piezoelectric plate.
A piezoelectric vibrating piece characterized by that. The piezoelectric vibrating piece according to any one of claims 1 to 4,
A pair of mount electrodes formed on the second main surface; and a second mesa portion formed on the second main surface;
The second mesa portion has a plurality of side surfaces with different projection widths on the second main surface,
At least one of the pair of mount electrodes is disposed on the opposite side of the top surface of the second mesa portion with the first side surface having the smallest projection width among the plurality of side surfaces of the second mesa portion interposed therebetween. Being
A piezoelectric vibrating piece characterized by that.   A piezoelectric vibrator comprising the piezoelectric vibrating piece according to claim 1. A piezoelectric vibrator in which the piezoelectric vibrating piece according to claim 5 is enclosed in a package.
The one mount electrode of the pair of mount electrodes is disposed on the opposite side of the top surface of the second mesa portion with the first side surface interposed therebetween,
The other mount electrode of the pair of mount electrodes is opposite to the top surface of the second mesa portion across a second side surface different from the first side surface among the plurality of side surfaces of the second mesa portion. Placed on the side
A mounting member disposed between the pair of mount electrodes of the piezoelectric vibrating piece and the package, and mounting the piezoelectric vibrating piece on the package;
The contact area of the mounting member on the one mount electrode is wider than the contact area of the mounting member on the other mount electrode,
A piezoelectric vibrator characterized by that. A method of manufacturing a piezoelectric vibrating piece having a piezoelectric plate formed by AT cut and having a first main surface, a second main surface and a side surface,
The piezoelectric vibrating piece has a mesa portion on at least one of the first main surface and the second main surface,
Forming a mesa mask of the outer shape pattern of the mesa portion on the surface of the wafer;
Etching the wafer through the mesa mask to form an external pattern of the mesa portion;
Forming a curved surface connected to the top surface of the mesa portion on the side surface of the mesa portion by wet etching the wafer;
A method of manufacturing a piezoelectric vibrating piece, comprising: The method of manufacturing a piezoelectric vibrating piece according to claim 8,
A curved surface connected to at least one of the first main surface and the second main surface is formed on a side surface of the piezoelectric plate,
In at least one of the step of forming the outer shape pattern of the mesa portion and the step of forming a curved surface on the side surface of the mesa portion, the first main main surface is formed on the side surface of the piezoelectric plate by wet etching the wafer. Forming a curved surface connected to at least one of the surface and the second main surface;
A method of manufacturing a piezoelectric vibrating piece. In the manufacturing method of the piezoelectric vibrating piece according to claim 8 or 9,
The mesa portion has a plurality of mesa step portions stacked in a staircase pattern,
The plurality of mesa step portions include a first mesa step portion arranged on the inner side in the thickness direction of the piezoelectric plate and a second mesa step portion arranged on the outer side in the thickness direction of the piezoelectric plate. And
Repeating the step of forming the mesa mask and the step of forming the outer shape pattern of the mesa portion to form the first mesa step portion and the second mesa step portion;
In the step of forming a curved surface on the side surface of the mesa portion, a curved surface connected to the top surface of the first mesa step portion is formed on the side surface of the first mesa step portion,
The step of forming a curved surface on the side surface of the first mesa step portion is performed by wet etching the wafer in the step of forming the outer shape pattern of the second mesa step portion.
A method of manufacturing a piezoelectric vibrating piece.

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