Piezoelectric vibration element and piezoelectric device

Abstract

A piezoelectric blank of a piezoelectric vibration element according to the present invention includes a vibrating portion and a fixed portion constituting mutually different regions in a plan view. A third surface on a first side of the fixed portion is higher toward the first side than a first surface on the first side of the vibrating portion. An excitation electrode overlaps the first surface. A lead-out electrode is led out from the excitation electrode and overlaps the third surface. A crystal blank has a recessed portion that is recessed from the third surface toward a second side on the opposite side to the first side. In the recessed portion, an edge portion of the third surface on the first surface side is cut away in a plan view. The lead-out electrode has a part leading from the first surface to the third surface via the recessed portion. A first edge portion has a first part edge portion and a second part edge portion. The first part edge portion and the second part edge portion form a corner portion in a plan view. In a first recessed portion, at least one of the first part edge portion and the second part edge portion of the corner portion is cut away.

Description

[Technical field]

[0001] The present disclosure relates to a piezoelectric vibration element and a piezoelectric device. [Background technology]

[0002] Known examples of piezoelectric devices include quartz crystal resonators and quartz crystal oscillators. These piezoelectric devices have a piezoelectric vibration element that vibrates when an AC voltage is applied to it. The piezoelectric vibration element has, for example, a plate-shaped piezoelectric plate (e.g., a quartz crystal plate), a pair of excitation electrodes located on a pair of main surfaces (the widest surfaces of the plate shape; the front and back of the plate shape; the same applies below) of the piezoelectric plate, and a pair of extraction electrodes drawn from the pair of excitation electrodes. The pair of extraction electrodes are bonded to pads of a package, for example, by a conductive bonding material. This allows the piezoelectric vibration element to be mounted in the package. Then, an AC voltage is applied to the pair of extraction electrodes, and the AC voltage is applied to the piezoelectric plate by the pair of excitation electrodes.

[0003] Patent Document 1 discloses a piezoelectric base plate having a vibrating portion and a fixed portion which constitute different regions in a plan view. The vibrating portion is, for example, a portion having a pair of excitation electrodes, and is flat. The fixed portion is, for example, a portion having a pair of extraction electrodes, and is thicker than the vibrating portion. In Patent Document 1, the piezoelectric base plate further has a recess on the edge of the fixed portion on the vibrating portion side. The extraction electrode extends from the vibrating portion to the fixed portion via the recess. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-191579 A Summary of the Invention

[0005] A piezoelectric vibration element according to an embodiment of the present disclosure includes a piezoelectric base plate, a first excitation electrode, and a first extraction electrode. The piezoelectric base plate includes a vibration section and a fixed section that form different regions from each other in a plan view. The vibration section includes a first surface facing a first side and a second surface facing a second side opposite to the first side. The fixed section includes a third surface facing the first side and a fourth surface facing the second side. The third surface is higher on the first side than the first surface. The first excitation electrode overlaps the first surface. The first extraction electrode is extracted from the first excitation electrode and overlaps the third surface. The piezoelectric base plate includes a first recess recessed from the third surface to the second side. The first recess cuts out a first edge portion of the third surface on the side of the first surface in a plan view. The first extraction electrode includes a portion extending from the first surface to the third surface via the first recess.

[0006] In one example, the first edge has a first partial edge and a second partial edge. The first partial edge is located on one side of the vibration part in a first direction in a plan view. The second partial edge is located on one side of the vibration part in a second direction perpendicular to the first direction in a plan view, and forms a corner with the first partial edge. The first recess cuts out at least one of the first partial edge and the second partial edge at the corner.

[0007] In one example, when the size of the first recess in a direction along the first edge portion is referred to as a width, a side surface of the first recess that intersects with the first edge portion in a plan view has an inclined surface that inclines from a bottom of the first recess to the third surface in a direction in which the width of the first recess becomes larger toward the first side. The extraction electrode has a portion that extends from the bottom of the first recess to the third surface via the inclined surface.

[0008] A piezoelectric device according to one aspect of the present disclosure includes the above-described piezoelectric vibration element and a package in which the piezoelectric vibration element is mounted. [Brief description of the drawings]

[0009] [Figure 1] 1 is a perspective view of a quartz crystal vibrating element according to a first embodiment. [Diagram 2] FIG. 2 is an enlarged plan view showing a region II in FIG. [Diagram 3] FIG. 3 is an enlarged plan view of region III in FIG. 2. [Figure 4] 4 is a cross-sectional view taken along line IV-IV in FIG. 3 . [Diagram 5] 4 is a cross-sectional view taken along line VV in FIG. 3 . [Figure 6] FIG. 2 is a perspective view showing an application example of the quartz crystal vibration element of FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 11 is a plan view showing another example of the extraction electrode and the recessed portion. [Figure 9A] FIG. 11 is a schematic plan view showing another example of the position of the fixing portion. [Figure 9B] FIG. 13 is a schematic plan view showing still another example of the position of the fixing portion. [Figure 10] 10A and 10B are cross-sectional views showing other examples of the thickness of the fixing portion. [Figure 11] FIG. 11 is a perspective view of a quartz crystal vibrating element according to a second embodiment. [Figure 12] 12. A cross-sectional view taken along line XII-XII in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a quartz crystal vibration element (hereinafter, simply referred to as a "quartz crystal element") according to an embodiment will be described with reference to the drawings. Note that the drawings used in the following description are schematic, and the dimensional ratios and the like in the drawings do not necessarily correspond to the actual ones. Similarly, the dimensional ratios and the like between the drawings do not necessarily correspond. Unless otherwise specified, a planar view refers to a view parallel to the Y' direction of the XY'Z' coordinate system shown in FIG. 1 etc.

[0011] (Overview of quartz crystal elements) Fig. 1 is a perspective view of a quartz crystal element 1 according to an embodiment (more specifically, the first embodiment). Fig. 2 is an enlarged plan view of region II in Fig. 1. Note that the quartz crystal element 1 is configured, for example, to be rotationally symmetrical by 180° with respect to a center line CL (Fig. 2) parallel to the X-axis. Therefore, the perspective view of the quartz crystal element 1 viewed from the -Y' side is the same as Fig. 1.

[0012] The crystal element 1 generates vibrations, for example, when an AC voltage is applied to it. This vibration is used, for example, to generate an oscillation signal whose signal strength (for example, voltage and / or current) oscillates at a certain frequency. In other words, the crystal element 1 is included, for example, in a crystal resonator or a crystal oscillator.

[0013] The quartz crystal element 1 has a quartz crystal plate 3, and a first conductor pattern 5A and a second conductor pattern 5B (hereinafter referred to as "conductor patterns 5", and there may be no distinction between the two) that overlap the quartz crystal plate 3. The two conductor patterns 5 are not short-circuited to each other. Each conductor pattern 5 has an excitation electrode 7 and an extraction electrode 9 that is extracted from the excitation electrode 7. In other words, the quartz crystal element 1 has a pair of excitation electrodes 7 and a pair of extraction electrodes 9 connected to the pair of excitation electrodes 7.

[0014] The pair of extraction electrodes 9 contribute to the mounting of the crystal element 1. Specifically, for example, as shown in FIG. 7 described later, the extraction electrodes 9 and pads 111 of the package 103 are bonded with bumps 105 made of a conductive bonding material, thereby mounting the crystal element 1 on the package 103. Note that the crystal element 1 may be mounted on a member (e.g., a circuit board) other than the package 103, but for convenience, in the description of the embodiment, it may be expressed on the assumption that it is mounted on the package 103. When an AC voltage is applied to the pair of extraction electrodes 9 via the package 103, an AC voltage (electric field) is applied to the crystal element plate 3 by the pair of excitation electrodes 7. This causes the crystal element plate to vibrate.

[0015] The quartz crystal plate 3 has a vibrating portion 11 that is excited by a pair of excitation electrodes 7, and a fixed portion 13 that is fixed to a package 103 by a pair of extraction electrodes 9. The fixed portion 13 is made thicker than the vibrating portion 11. This makes it possible, for example, to make the vibrating portion 11 thinner to enable high-frequency vibration, while ensuring the strength of the quartz crystal plate 3 by the fixed portion 13.

[0016] The quartz crystal plate 3 has one or more recesses 15 (multiple in the illustrated example) that recess the surface on the +Y' and -Y' sides of the fixed portion 13. The recesses 15 are formed by cutting out the edge 21a of the fixed portion 13 on the vibrating portion 11 side in a plan view. The extraction electrode 9 has a portion that extends from the surface of the vibrating portion 11 to the surface of the fixed portion 13 via the recesses 15. Note that the edge of the recess 15 is also a type of edge of the fixed portion 13, but in the following description, unless otherwise specified or unless there is any particular contradiction, the term edge of the fixed portion 13 (edge ​​21a) does not include the edge of the recess 15.

[0017] The recess 15 as described above can provide various effects as will be described later in detail. As one example, it can improve the reliability of the conduction of the extraction electrode 9 at the step between the fixed part 13 and the vibration part 11. The reason for this will be described later.

[0018] The specific configuration of the recess 15 may be any appropriate one. The recess 15 in this embodiment has, for example, the following new configuration. Located at the corner of the vibration part 11 (recess 615A in FIG. 11 described later) Of the side surfaces of the recess 15, a first side surface 15b (described below) that intersects with the edge portion 21a has a crystal plane. The first side surface 15b is inclined with respect to the thickness direction (Y' direction) of the quartz crystal plate 3. The width (length in the Z' direction) of the recess 15 is relatively large compared to the dimension of the predetermined portion. The depth (length in the X direction) of the recess 15 in a plan view is relatively large compared to the dimension of the predetermined portion. The bottom surface 15a (described later) of the recess 15 extends into the inside of the fixed part 13 in plan view. This seems natural in light of the explanation so far. An example of a mode that does not fall under this mode is a mode in which a third side surface 15d (described later) on the back side (+X side in the illustrated example) of the recess 15 in plan view spreads toward the vibrating part 11 side while inclining so as to become lower from the back side (+X side) toward the vibrating part 11 side (-X side), and reaches the edge part 21a of the fixed part 13 on the vibrating part 11 side (this mode may also be included in the technology according to the present disclosure).

[0019] The recess 15 according to the embodiment has the above-mentioned configuration, and thus can provide various effects as described in detail later. One example is the enhancement of the effect of improving the reliability of the conduction of the extraction electrode 9 described above. The reason for this will be described later.

[0020] The following will provide an outline of the process. Chapter 1 First embodiment 1. Quartz element 1 (Figs. 1 and 2) 1.1. Quartz crystal substrate 3 (structure other than recess 15) 1.1.1. Vibration part 11 1.1.2. Fixed part 13 1.1.3. Intermediate section 17 (section between vibration section 11 and fixed section 13) 1.2. Conductor pattern 5 1.2.1.Excitation electrode 7 1.2.2.Extraction electrode 9 1.3. Recess 15 (Figs. 3 to 5) 1.3.1. Recess 15 in General 1.3.2. Specific Examples of Shapes and Dimensions of the Recess 15 (Illustrated Examples) 1.4. Overlap Between Extraction Electrode 9 and Recess 15 1.5. Manufacturing method of the crystal element 1 1.6. Summary of Crystal Element 1 2. Example of use of crystal element 1 (Figs. 6 and 7) 3. Other Examples 3.1. Other examples of extraction electrodes and recesses (Fig. 8) 3.2. Other examples of the positions of the fixing parts (FIGS. 9A and 9B) 3.3.Other examples of thickness of fixing part (Fig. 10) Chapter 2 Second embodiment 1. Overview of quartz crystal elements 2.Crystal base plate 2.1. Entire quartz crystal substrate and vibrating part 2.2. Fixed part 2.3.Other 3. Conductive Pattern 4. Recess 5. Manufacturing method of quartz crystal elements 6. Summary of quartz crystal elements

[0021] (Chapter 1 First Embodiment) (1. Quartz crystal element) The crystal element 1 is, for example, a so-called AT-cut crystal vibration element. That is, the crystal blank 3 is an AT-cut crystal piece. A pair of excitation electrodes 7 overlap both sides of the crystal blank 3 (more specifically, the vibration part 11). When a voltage is applied in the thickness direction of the vibration part 11 by the pair of excitation electrodes 7, the vibration part 11 generates a so-called thickness-shear vibration. The resonance frequency of this vibration (in other words, the oscillation frequency) is basically determined by the thickness of the vibration part 11. The crystal element 1 may use a fundamental mode or an overtone mode. In the description of this embodiment, an aspect using the fundamental mode may be taken as an example.

[0022] Various dimensions of the quartz crystal element 1 (quartz crystal blank 3) may be set appropriately. Examples of dimensional ranges are given below. The length of the quartz crystal blank 3 in the X direction may be 500 μm or more and 1500 μm or less. The length of the quartz crystal blank 3 (vibration part 11, fixed part 13 and / or intermediate part 17) in the Z' direction may be 300 μm or more and 800 μm or less. The length of the vibration part 11 in the X direction may be 250 μm or more and 1150 μm or less (however, shorter than the length of the quartz crystal blank 3 in the X direction). The thickness of the vibration part 11 may be 16 μm or less. This corresponds to a frequency of approximately 100 MHz or more when using the fundamental vibration of thickness shear vibration in an AT-cut plate. The length of the fixed part 13 in the X direction may be 100 μm or more and 500 μm or less (however, shorter than the length of the quartz crystal blank 3 in the X direction). The thickness of the fixing portion 13 may be 50 μm or less.

[0023] (1.1. Crystal base plate) As described above, the quartz crystal blank 3 is, for example, an AT-cut quartz crystal piece. That is, when an orthogonal coordinate system XYZ consisting of an X axis (electrical axis), a Y axis (mechanical axis), and a Z axis (optical axis) in the quartz crystal is rotated about the X axis by 30° to 50° (for example, 35°15′) to define an orthogonal coordinate system XY'Z', the quartz crystal blank 3 is a plate having a pair of main surfaces that are basically parallel to the XZ' plane.

[0024] The relationship between the positive and negative X-axis and the configuration of the quartz crystal element 1 (from another perspective, the shape of the quartz crystal blank 3) may be the opposite of that shown in the figure. However, in the description of the embodiment, the description may be given on the premise of the relationship shown in the figure.

[0025] The planar shape of the quartz crystal blank 3 may be set as appropriate. In the illustrated example, the planar shape of the quartz crystal blank 3 is a rectangle having sides parallel to the Z'-axis and the X-axis. Other planar shapes of the quartz crystal blank 3 include, for example, a circle and an ellipse. Also included is a shape in which one or more of the four sides of the rectangle are curved (for example, arc) and bulge outward.

[0026] Note that the term "rectangle" includes squares and rectangles in the narrow sense. In addition, unless otherwise specified, when referring to a rectangle or rectangular shape, it does not have to be strictly a square or rectangular shape, and the corners may be chamfered, etc. The same applies to the description of shapes other than the planar shape of the quartz crystal plate 3.

[0027] In the planar shape of the quartz crystal blank 3, the X direction (the direction in which the principal surfaces slide relative to each other in thickness shear vibration) may be the longitudinal direction (in the illustrated example), or the Z' direction may be the longitudinal direction, or the length in the Z' direction may be equal to the length in the X direction. In the illustrated example, the quartz crystal blank 3 has the X direction as the longitudinal direction. In other words, the quartz crystal blank 3 has a long side parallel to the X axis and a short side parallel to the Z' axis.

[0028] The quartz crystal blank 3 may be fabricated, for example, by etching quartz crystal. In this case, due to the anisotropy of quartz crystal with respect to etching, the side surface of the quartz crystal blank 3 or each part thereof may have an inclined surface (a crystal surface in another perspective). However, in the description of this embodiment, illustration of such an inclined surface may be omitted, or the shape and dimensions may be described ignoring the existence of the inclined surface. In this case, the correspondence between the shape and dimensions of the quartz crystal blank 3 exemplified in the description of the embodiment and the actual shape and dimensions having the inclined surface may be reasonably determined in consideration of the characteristics of the quartz crystal element 1, etc. For example, if the side surface of the quartz crystal blank 3 (or each part) includes an inclined surface, and as a result, the positions of the main surface on the +Y' side and the main surface on the -Y' side in the XZ' plane are shifted from each other, depending on the direction of the shift, the description of the shape and dimensions of the quartz crystal blank 3 (or each part) may be interpreted as being based on the maximum shape and dimensions in planar perspective.

[0029] As described above, the quartz crystal plate 3 has a vibrating portion 11 and a fixed portion 13 which form different regions in a plan view and have different thicknesses. Furthermore, the quartz crystal plate 3 has an intermediate portion 17 which forms the region between the vibrating portion 11 and the fixed portion 13 in a plan view. The intermediate portion 17 is thicker on the fixed portion 13 side. These portions will be described below.

[0030] (1.1.1. Vibration part) The vibrating part 11 includes at least the inner region of the quartz crystal plate 3 in plan view. The inner region here refers to a region that is away from the outer edge of the quartz crystal plate 3. More specifically, for example, the vibrating part 11 may include a region that includes the centroid (center) of the quartz crystal plate 3 in plan view. To be clear, the centroid is a point at which the first moment of area with respect to any axis passing through that point is zero.

[0031] The planar shape and dimensions of the vibration section 11 may be set appropriately. In the illustrated example, the planar shape of the vibration section 11 is a rectangle having sides parallel to the Z' axis and the X axis. Other planar shapes of the vibration section 11 include, for example, a circle and an ellipse. Also, a shape in which at least one of the four sides of a rectangle is curved (for example, an arc) and bulges outward can be included. In the planar shape of the vibration section 11, the X direction (the direction in which the main surfaces slide relative to each other in thickness shear vibration) may be the longitudinal direction, the Z' direction may be the longitudinal direction, or the length in the Z' direction may be equal to the length in the X direction (illustrated example).

[0032] For example, the vibrating part 11 occupies a relatively large portion of the area (area in plan view) of the quartz crystal plate 3. For example, the vibrating part 11 occupies more than half the area of ​​the quartz crystal plate 3. However, the vibrating part 11 may occupy less than half the area of ​​the quartz crystal plate 3.

[0033] The vibration part 11 is flat and parallel to the XZ' plane, and has main surfaces (first surface 19A and second surface 19B) parallel to the XZ' plane. The first surface 19A faces the +Y' side (one side in the thickness direction of the quartz crystal plate 3) and is perpendicular to the Y' axis (thickness direction). The second surface 19B faces the -Y' side (the other side in the thickness direction of the quartz crystal plate 3) and is perpendicular to the Y' axis (thickness direction). From another perspective, the first surface 19A and the second surface 19B are parallel to each other.

[0034] (1.1.2. Fixed part) The fixed portion 13 includes at least a part of the region on the outer periphery of the quartz crystal plate 3 in a plan view. From another perspective, the fixed portion 13 is adjacent to at least a part of the outer edge of the vibration portion 11 across the intermediate portion 17. The length over which the fixed portion 13 and the outer edge of the vibration portion 11 are adjacent to each other (the length in the direction along the outer edge of the vibration portion 11) may be set appropriately, as will be understood from other examples described below (Figures 9A and 9B). In the illustrated example, the fixed portion 13 is adjacent to the vibration portion 11 along one side of the rectangular vibration portion 11.

[0035] The direction in which the fixed portion 13 and the vibrating portion 11 are adjacent to each other across the intermediate portion 17 may be the X direction (the direction in which the principal surfaces slide relative to each other in thickness shear vibration) (in the illustrated example) or the Z' direction. From another perspective, the adjacent direction may be the short side direction of the vibrating portion 11, or the long side direction of the vibrating portion 11, or such a distinction may not be possible (in the illustrated example). Furthermore, the relationship between the adjacent direction and the long side direction of the quartz crystal plate 3 is also arbitrary.

[0036] The planar shape (in this paragraph, recess 15 is ignored) and dimensions of fixed portion 13 may be set as appropriate. For example, fixed portion 13 may have a shape that follows the outer edge of vibrating portion 11 with a constant width (example shown), or may have a shape in which the shape of the edge on the vibrating portion 11 side is different from the shape of the edge on the opposite side to vibrating portion 11. In the example shown, fixed portion 13 is rectangular with a long side parallel to one side of vibrating portion 11.

[0037] In a direction (Z' direction in the illustrated example) perpendicular to the direction in which fixed portion 13 and vibration portion 11 are adjacent to each other with intermediate portion 17 in between, fixed portion 13 may be smaller, equal to (in the illustrated example), or larger than vibration portion 11. The length of fixed portion 13 in the adjacent direction (X direction in the illustrated example) is also arbitrary. In the illustrated example, the length of fixed portion 13 in the X direction is shorter than the length of vibration portion 11 in the X direction.

[0038] The fixed portion 13 is, for example, a flat plate parallel to the XZ' plane, similar to the vibrating portion 11. However, the fixed portion 13 may have a shape that does not have a width that can be considered as a plate. The fixed portion 13 has main surfaces (third surface 21A and fourth surface 21B) parallel to the XZ' plane, similar to the vibrating portion 11. The third surface 21A faces the +Y' side (one side in the thickness direction of the quartz crystal plate 3) and is perpendicular to the Y' axis (thickness direction). The fourth surface 21B faces the -Y' side (the other side in the thickness direction of the quartz crystal plate 3) and is perpendicular to the Y' axis (thickness direction). From another perspective, the third surface 21A and the fourth surface 21B are parallel to each other. From yet another perspective, the third surface 21A and the fourth surface 21B are parallel to the first surface 19A and the second surface 19B.

[0039] As described above, the fixed portion 13 is thicker than the vibrating portion 11. More specifically, the fixed portion 13 is higher on both sides in the thickness direction (Y' direction) than the vibrating portion 11. From another perspective, the third surface 21A facing one side (+Y' side) in the thickness direction is located closer to the one side than the first surface 19A facing the one side. Also, the fourth surface 21B facing the other side (-Y' side) in the thickness direction is located closer to the other side than the second surface 19B facing the other side.

[0040] The height h1 (reference symbol in FIG. 4) from the first surface 19A to the third surface 21A and the height from the second surface 19B to the fourth surface 21B may be greater than the other, or may be equal to each other. In this embodiment, the embodiment in which the two are equal is taken as an example. Furthermore, these heights h1 may be smaller, equal to, or greater than the thickness t1 (reference symbol in FIG. 4) of the vibrating section 11.

[0041] (1.1.3. Middle section) The intermediate portion 17 extends, for example, over approximately the entire edge of the vibration portion 11 on the fixed portion 13 side and / or the entire edge 21a of the fixed portion 13 on the vibration portion 11 side. The size of the intermediate portion 17 in a plan view may be set appropriately. For example, in a direction (Z' direction in the illustrated example) perpendicular to the direction in which the fixed portion 13 and the vibration portion 11 are adjacent to each other via the intermediate portion 17, the intermediate portion 17 may be smaller, equal (in the illustrated example), or larger than the vibration portion 11 and / or the fixed portion 13. The length of the intermediate portion 17 in the adjacent direction (X direction in the illustrated example) is also arbitrary. In the illustrated example, the length of the intermediate portion 17 in the X direction is shorter than the length of the fixed portion 13 in the X direction.

[0042] As described above, the intermediate portion 17 is thicker toward the fixed portion 13 side. Specifically, the intermediate portion 17 has a fifth surface 23A and a sixth surface 23B that are inclined so as to be thicker toward the fixed portion 13 side. The fifth surface 23A faces one side (+Y' side) in the thickness direction and is inclined with respect to the first surface 19A in a direction in which the fixed portion 13 side is located on the one side with respect to the vibration portion 11 side. The sixth surface 23B faces the other side (-Y' side) in the thickness direction and is inclined with respect to the second surface 19B in a direction in which the fixed portion 13 side is located on the other side with respect to the vibration portion 11 side. Each of the fifth surface 23A and the sixth surface 23B is, for example, generally constituted by one plane.

[0043] The inclination angle of the fifth surface 23A and the inclination angle of the sixth surface 23B may be the same or different from each other. When they are the same, the state in which the vibration leaking and propagating from the portion of the vibration part 11 sandwiched between the pair of excitation electrodes 7 is reflected by the inclined portion of the intermediate part 17 can be made the same on the upper surface side and the lower surface side. In the description of this embodiment, the embodiment in which both are the same is taken as an example. The specific magnitude of this inclination angle may be set appropriately. For example, as shown in FIG. 4 described later, the angle of the fifth surface 23A or the sixth surface 23B with respect to the normal line (Y' axis from another point of view) of the main surface of the fixed part 13 or the vibration part 11 is θ1. In this case, the angle θ1 may be smaller than 45° or may be 45° or more.

[0044] The fifth surface 23A and the sixth surface 23B may be crystal planes that appear due to the anisotropy of the etching of the quartz crystal when the quartz crystal plate 3 is formed by etching. The crystal planes that appear in this case (or from another perspective, the inclination angle θ1) may be appropriately selected depending on the etching conditions. An example of the inclination angle θ1 is about 55° (e.g., 53° or more and 57° or less). An example of the inclination angle θ1 in a case where the positive and negative signs of the X-axis are reversed from the illustrated example is about 27° (e.g., 25° or more and 29° or less).

[0045] The first surface 19A and the fifth surface 23A intersect with each other and form a corner in a side view or a cross-sectional view (when viewed in the Z' direction). Although not particularly shown, this corner may have a curve or a step when viewed extremely microscopically. In this case, the length of the curve or the height of the step is, for example, less than 0.1 μm. Furthermore, even if not viewed microscopically, the first surface 19A and the fifth surface 23A may have a curve or a step between them. Although the boundary between the first surface 19A and the fifth surface 23A has been described, the above description may be applied to the boundary between the second surface 19B and the sixth surface 23B.

[0046] The boundary between the first surface 19A and the fifth surface 23A and the boundary between the second surface 19B and the sixth surface 23B may be aligned or may be shifted from each other in the direction in which the intermediate portion 17 and the vibration portion 11 are adjacent to each other (the X direction in the illustrated example). When the positions are aligned, it goes without saying that a tolerance may exist.

[0047] The third surface 21A and the fifth surface 23A intersect with each other and form a corner in a side view or a cross-sectional view (when viewed in the Z' direction). Although not particularly shown, this corner may have a curve or a step when viewed microscopically. For example, a step may be formed that extends from the edge 21a of the third surface 21A to the -Y' side and includes a plane that is generally perpendicular to the X-axis. The height of this step (size in the Y' direction) is, for example, less than 1 μm. Although the boundary between the third surface 21A and the fifth surface 23A has been described, the above description may be applied to the boundary between the fourth surface 21B and the sixth surface 23B.

[0048] The boundary between the third surface 21A and the fifth surface 23A and the boundary between the fourth surface 21B and the sixth surface 23B may be aligned or may be shifted from each other in the direction in which the fixed portion 13 and the intermediate portion 17 are adjacent to each other (the X direction in the illustrated example). When the positions are aligned, it goes without saying that a tolerance may exist.

[0049] (1.2. Conductive Pattern) The material of the conductor pattern 5 may be, for example, a metal. The conductor pattern 5 may be composed of one metal layer made of a single material, or may be composed of a plurality of metal layers made of different materials stacked together. Examples of the material of the metal layer include nickel, chromium, nichrome, titanium, gold, silver, or alloys containing these. The conductor pattern 5 may be composed of, for example, the entire region (in other words, the area) of the conductor pattern 5 made of the same material, or some regions may be composed of different materials.

[0050] (1.2.1. Excitation electrode) The pair of excitation electrodes 7 are located on both main surfaces of the vibration section 11 to apply a voltage to the vibration section 11 as described above. The pair of excitation electrodes 7 have positions, shapes, and sizes that, for example, overlap each other almost exactly in a planar perspective. However, there may be portions that do not overlap each other. The position, shape, size, etc. of the excitation electrodes 7 in a planar view may be set appropriately.

[0051] For example, the excitation electrode 7 is located in a region on the central side of the vibration part 11. From another point of view, the excitation electrode 7 is located away from the outer edge of the vibration part 11. The center of the excitation electrode 7, for example, roughly coincides with the center of the vibration part 11 and / or its main surface in the Z' direction. In addition, the center of the excitation electrode 7 may be located on the +X side, may coincide with the center of the vibration part 11, or may be located on the -X side in the X direction. The excitation electrode 7 may occupy, for example, ⅓ or more of the area of ​​the vibration part 11.

[0052] Also, for example, the shape of the excitation electrode 7 may be similar to the shape of the vibration part 11 (example of FIG. 1), or may be different. An example of the former is, for example, as in the example of FIG. 1, a mode in which the shape of the vibration part 11 is rectangular, while the shape of the excitation electrode 7 is rectangular having a long side parallel to the long side of the vibration part 11 (at least one of which may be square). An example of the latter is a mode in which the shape of the vibration part 11 is rectangular, while the shape of the excitation electrode 7 is circular (example of FIG. 11 described later), elliptical, or polygonal (except for a square).

[0053] (1.2.2. Extraction electrode) The extraction electrode 9 has a pad portion 9a joined to a pad 111 of the package 103 and a wiring portion 9b connecting the pad portion 9a to the excitation electrode 7.

[0054] The pad portion 9a of each conductive pattern 5 overlaps at least the lower surface (the surface on the pad 111 side in FIG. 7; the same applies to the surfaces of other portions below) of the fixed portion 13. That is, a pair of pad portions 9a of a pair of conductive patterns 5 are arranged side by side on the lower surface of the fixed portion 13.

[0055] In the illustrated example, each conductor pattern 5 also has a pad portion 9a on the upper surface of the fixed portion 13 (the surface opposite to the pad 111; the same applies to the surfaces of other portions below). That is, each conductor pattern 5 has two pad portions 9a, and one pair of conductor patterns 5 has a total of two pairs of pad portions 9a. This makes it possible, for example, for the crystal element 1 to have either of the pair of main surfaces as the lower surface. Note that, unlike the illustrated example, one pair of conductor patterns 5 may have only one pair of pad portions 9a.

[0056] The pair of pads 9a on the lower surface (or upper surface) of the quartz crystal element 1 are aligned in the Z' direction. The pair of pads 9a on the lower surface (or upper surface) may have positions, shapes, and sizes that are, for example, approximately symmetrical with respect to a center line CL that is parallel to the X-axis of the quartz crystal plate 3. The pair of pads 9a on the lower surface and the pair of pads 9a on the upper surface may have the same configuration.

[0057] In each conductor pattern 5, the pad portion 9a on the upper surface and the pad portion 9a on the lower surface of the crystal element 1 are connected by a portion (reference numerals omitted) located on the side surface of each conductor pattern 5 facing the X direction and / or the side surface facing the Z' direction of the crystal blank 3. This connects the excitation electrode 7 on the upper surface (or the lower surface) and the pad portion 9a on the lower surface (or the upper surface). Unlike the illustrated example, in a mode that does not have the pad portion 9a on the upper surface, for example, the wiring portion 9b may be extended to the side surface facing the X direction and / or the side surface facing the Z' direction of the crystal blank 3 to connect the excitation electrode 7 on the upper surface and the pad portion 9a on the lower surface.

[0058] The specific position, shape, size, etc. of each pad portion 9a may be set appropriately. In the illustrated example, the pad portion 9a is rectangular. Unlike the illustrated example, the pad portion 9a may have a recess on the opposite side to the vibration portion 11 and on the center side of the fixed portion 13 in the Z' direction. In the illustrated example, the pad portion 9a overlaps not only the fixed portion 13 but also the intermediate portion 17 beyond the edge portion 21a, and further overlaps the vibration portion 11. In addition, the pad portion 9a reaches the end of the fixed portion 13 on the opposite side (+X side) to the vibration portion 11, and also reaches the end on the +Z' side or -Z side. The pad portion 9a may be longer in either the X direction or the Z' direction than the other. The length of the pad portion 9a in the Z' direction may be 1 / 3 or more of the length of the fixed portion 13 in the Z' direction (in the illustrated example), or may be less than 1 / 3.

[0059] In each conductor pattern 5, the wiring portion 9b extends from, for example, the excitation electrode 7 to reach the pad portion 9a on the surface (upper surface or lower surface) on which the excitation electrode 7 is located. In the illustrated example, as described above, the pad portion 9a overlaps not only the fixed portion 13 (more specifically, the third surface 21A or the fourth surface 21B) but also the vibration portion 11 (more specifically, the first surface 19A or the second surface 19B). Thus, the wiring portion 9b overlaps only the vibration portion 11 and does not overlap the fixed portion 13.

[0060] The specific position, shape, size, etc. of the wiring portion 9b may be set as appropriate. In the illustrated example, the wiring portion 9b extends parallel to the X direction with a constant width from the end of the edge portion of the excitation electrode 7 on the fixed portion 13 side. Unlike the illustrated example, the wiring portion 9b may extend from a corner of the excitation electrode 7, extend obliquely in the X direction, or have a variable width. To be clear, the width (length in the Z' direction) of the wiring portion 9b is narrower than the width (length in the Z' direction) of the pad portion 9a.

[0061] (1.3. Recess) In the following, first, the recess 15 will be generally described, and then a specific example (one example) of the shape and dimensions of the recess 15 will be described with reference to FIGS.

[0062] In the following description, for convenience, the recess 15 on the third surface 21A side and the recess 15 on the fourth surface 21B side may be described as an example. In this case, unless there is a particular contradiction, the description of the recess 15 on the third surface 21A side may be applied to the recess 15 on the fourth surface 21B side. However, the terms "third surface 21A" and "fourth surface 21B" are mutually substituted, the terms "first surface 19A" and "second surface 19B" are mutually substituted, the terms "fifth surface 23A" and "sixth surface 23B" are mutually substituted, the terms "+Y'" and "-Y'" are mutually substituted, and the terms "+Z'" and "-Z'" are mutually substituted.

[0063] (1.3.1. Recesses in general) As described above, the recess 15 recesses the third surface 21A of the fixed portion 13, and cuts out the edge portion 21a of the third surface 21A on the vibration portion 11 side in a plan view. In this embodiment, the intermediate portion 17 is located on the vibration portion 11 side of the fixed portion 13, and the recess 15 also recesses the fifth surface 23A of the intermediate portion 17. The recess 15 may reach the edge portion of the intermediate portion 17 on the vibration portion 11 side in a plan view (as shown in the example), or may not reach it.

[0064] The number of recesses 15 is arbitrary. For example, in the illustrated example, the number of recesses 15 is plural on the third surface 21A of the quartz crystal plate 3. The third surface 21A has at least one recess 15 (plural in the illustrated example, more specifically, three) overlapping with each extraction electrode 9 (more specifically, pad portion 9a). When the number of recesses 15 on each extraction electrode 9 is plural, this number may be, for example, 2 to 5 or less, or 2 to 4 or less. Unlike the illustrated example, the third surface 21A may have only one recess 15 for each extraction electrode 9 (two recesses 15 in total on the third surface 21A). Also, as will be understood from FIG. 8 described later, the third surface 21A may have recesses 15 only for the extraction electrodes 9 connected to the excitation electrodes 7 overlapping the first surface 19A connected to the third surface 21A. In other words, the third surface 21A does not need to have the recess 15 for the extraction electrode 9 connected to the excitation electrode 7 overlapping the second surface 19B.

[0065] On the +Y' or -Y' side surface of the crystal plate 3, the arrangement of the multiple recesses 15 may be line-symmetrical with respect to the center line CL parallel to the X direction of the crystal plate 3 (illustrated example), or may not be line-symmetrical. In the case of line symmetry, the state in which the vibration leaking and propagating from the part of the vibration part 11 sandwiched between a pair of excitation electrodes 7 is reflected in the area where the multiple recesses 15 are arranged can be the same on the +Z' side and the -Z' side with respect to the center line CL. In the Z' direction, the pitch (e.g., the distance between the centers of the recesses 15) or the interval (the length in the Z' direction of the area where the recesses 15 are not arranged) of the multiple recesses 15 may be constant (illustrated example) or may not be constant on one side (+Z' or -Z' side) of the center line CL. In addition, the interval between the recesses 15 may be smaller than, equal to (illustrated example) the width (length in the Z' direction of the recesses 15. For example, the maximum width) of the recesses 15, or may be longer.

[0066] The shapes and dimensions of the recesses 15 may be the same as each other or may be different from each other. In the illustrated example, the recesses 15 basically have the same shapes and dimensions as each other.

[0067] The shape and dimensions of each recess 15 are arbitrary. For example, the depth (size in the Y' direction) of the recess 15 may or may not be constant in the X direction and / or the Z' direction (illustrated example). From another perspective, the inner surface of the recess 15 may or may not have an inclined surface inclined with respect to the Y' direction (illustrated example). Such an inclined surface may or may not be a crystal plane that appears by etching.

[0068] Also, for example, the height (position in the Y' direction) of the end of the recess 15 that recesses the third surface 21A on the vibration section 11 side (-X side) in a plan view may be equal to (in the illustrated example), higher, or lower than the height of the first surface 19A. In other words, the depth of the recess 15 from the third surface 21A at the end may be equal to (in the illustrated example), lower, or higher than the height h1 from the first surface 19A to the third surface 21A. For example, the depth of the recess 15 from the third surface 21A at the end may be 50% or more and 100% or less of the height h1 from the first surface 19A to the third surface 21A.

[0069] In addition, the depth of recess 15 from edge 21a on the vibrating section 11 side of third surface 21A in plan view (length of recess 15 in the X direction; for example, the maximum length if it varies depending on the position in the Z' direction or Y' direction) may be longer, equal to (in the illustrated example) or shorter than the width of recess 15 (length in the Z' direction; for example, the maximum length if it varies depending on the position in the X direction or Y' direction). In addition, the depth of recess 15 (length of recess 15 in the Y' direction; for example, the maximum length if it varies depending on the position in the X direction or Z' direction) may be smaller, equal to, or larger than the depth of recess 15 and / or the width of recess 15.

[0070] Moreover, the overall shape of recess 15 in plan view (or, from another perspective, the shape of the opening on the +Y' side of recess 15) may be, for example, rectangular (as in the illustrated example), triangular with one side located on the vibrating section 11 side, semicircular with a string located on the vibrating section 11 side, elliptical, or oval (a rectangle with the short side curved outward). In the case of a rectangular shape, for example, the manufacturing reproducibility of recess 15 is improved. The same applies to the shape in plan view of the portion of recess 15 located on fixed section 13.

[0071] (1.3.2. Specific examples of shapes and dimensions of recesses) Fig. 3 is an enlarged plan view of region III in Fig. 2. Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 3. Fig. 5 is a cross-sectional view taken along line VV in Fig. 3. However, in Figs. 3 to 5, the conductor pattern 5 is omitted, and only the quartz crystal plate 3 is shown.

[0072] 1 and 2 show the shape of the recess 15 more typically than in Figs. 3 to 5. Specifically, a first side surface 15b and a second side surface 15c, which will be described later, are drawn parallel to the Y'-axis without being inclined relative to the Y'-axis. However, in reality, most of the first side surface 15b and the second side surface 15c may be parallel to the Y'-axis as shown in Figs. 1 and 2.

[0073] Here, it may be assumed that the recesses 15 are formed by etching. In addition, Figs. 3 to 5 show examples of shapes of the recesses 15 when the effect of the anisotropy of quartz crystal on etching is typically manifested. In the following description, some expressions may be made based on the shapes shown in the drawings. However, the actual shape may deviate from the shapes shown in the drawings (for example, a shape with relatively large rounding at the corners).

[0074] The recess 15 has, for example, a bottom surface 15a that is substantially perpendicular to the Y' axis, and a plurality of side surfaces (first side surface 15b, second side surface 15c, and third side surface 15d) that rise from the bottom surface 15a toward the +Y' side and surround the bottom surface 15a. The first side surface 15b and the second side surface 15c are side surfaces that intersect (for example, perpendicular to) the edge portion 21a of the fixed portion 13 on the vibration portion 11 side in a plan view. In other words, the first side surface 15b and the second side surface 15c are side surfaces that are located in a direction along the edge portion 21a with respect to the bottom surface 15a. The third side surface 15d is a side surface that is located on the opposite side of the vibration portion 11 with respect to the bottom surface 15a in a plan view.

[0075] Although not shown, for example, the recess 15 may be triangular with one side located on the vibrating section 11 side, or semicircular with a string located on the vibrating section 11 side, as described above. As in this embodiment, the first side 15b, the second side 15c, and the third side 15d do not have to be clearly distinguishable. From another point of view, it is not essential for the recess 15 to have three sides.

[0076] The bottom surface 15a is, for example, connected to the first surface 19A of the vibration section 11 and is flush with the first surface 19A. Flush means that both surfaces have the same height and are parallel to each other. However, as can be understood from the general description of the recess 15 described above, unlike the illustrated example, the bottom surface 15a may be at a different height from the first surface 19A, may be inclined with respect to the first surface 19A, or may not reach the first surface 19A in a plan view.

[0077] At least one of the first side surface 15b, the second side surface 15c, and the third side surface 15d (all the side surfaces in the illustrated example) is an inclined surface inclined with respect to the thickness direction (Y' direction) of the quartz crystal plate 3 (has an inclined surface). More specifically, each inclined surface is inclined in a direction in which the recess 15 (width or depth) becomes larger toward the upper side (here, the +Y' side, the third surface 21A side) of the recess 15. The inclination angle of each inclined surface with respect to the Y' direction (θ2 in FIG. 4, θ3 and θ4 in FIG. 5) may be set appropriately. For example, each inclination angle may be 1° or more, 10° or more, 20° or more, or 50° or more, and may be 70° or less, 60° or less, 40° or less, or 30° or less, and any combination of the above lower limit and upper limit may be used without causing any contradiction.

[0078] Unlike the illustrated example, each side may not be composed of one plane, but may include multiple planes at different positions in the Y' direction, or may include one or more curved surfaces that are concave and / or convex in cross-sectional view. From another perspective, each side may not be composed of one straight line, but may include two or more straight lines or one or more curved lines in a cross section parallel to the Y' direction. When the inclination angle of each side is mentioned without special notice, the description of the inclination angle may be taken as a description of the representative value of the inclination angle of each side, unless a contradiction occurs. The representative value may be, for example, the inclination angle of one plane that occupies 50% or more or 80% or more of the area of ​​each side, or the average value of the inclination angle at each position for the entire area of ​​each side. And / or the representative value may be the inclination angle of a straight line that occupies 50% or more or 80% or more of the height of each side in the Y' direction in a cross section parallel to the Y' direction at any position of each side, or the average value of the inclination angle at each position for the entire length of each side.

[0079] At least one of the first side surface 15b, the second side surface 15c, and the third side surface 15d (all the side surfaces in the illustrated example) is a crystal plane (has a crystal plane) that appears due to, for example, the anisotropy of quartz crystal with respect to etching. The inclined surface described above may be realized by a crystal plane. In this case, the crystal plane that appears (from another point of view, the inclination angles θ2 to θ5) may be appropriately selected depending on the etching conditions.

[0080] Examples of inclination angles when each side surface is a crystal plane are given below. The inclination angle θ2 of the third side surface 15d with respect to the Y' axis may be the same as the inclination angle θ1 (already described) of the fifth surface 23A of the intermediate portion 17, or may be different. In the example of FIG. 4, they are the same. For example, the inclination angle θ2 may be about 55° (e.g., 53° or more and 57° or less). When the positive and negative signs of the X axis are reversed from those in the illustrated example, the inclination angle θ2 may be about 27° (e.g., 25° or more and 29° or less). The inclination angle θ3 of the side surface facing the -Z' side (the first side surface 15b in the illustrated example) of the first side surface 15b and the second side surface 15c of the recess 15 on the +Y' side with respect to the Y' axis may be about 54° (e.g., 52° or more and 56° or less). Of the first side 15b and second side 15c of the recess 15 on the +Y' side, the inclination angle θ4 of the side facing the +Z' side (second side 15c in the illustrated example) with respect to the Y' axis may be approximately 3° (for example, greater than or equal to 1° and less than or equal to 5°).

[0081] Unlike the illustrated example, each side surface may be composed of only a part of a crystal plane. Also, each side surface may have two or more different crystal planes (inclined planes with different inclination angles) at different positions in the Y' direction. The inclination angle of one of the one or more crystal planes of each side surface may be within the above range. The crystal plane having an inclination angle in the above range may or may not be a crystal plane that occupies a large part of each side surface. The crystal plane that occupies a large part of each side surface may occupy 50% or more, 80% or more, or 100% (however, slight rounding of the corners is ignored) of the area of ​​each side surface. And / or, the crystal plane that occupies a large part of each side surface may occupy 50% or more, 80% or more, or 100% (however, slight rounding of the corners is ignored) of the height of each side surface parallel to the Y' direction in a cross section parallel to the thickness direction (Y' direction) of the quartz crystal blank 3.

[0082] The third side surface 15d is inclined at an inclination angle θ2. Therefore, when the height from the first surface 19A of the vibrating portion 11 to the third surface 21A of the fixed portion 13 is h1 (FIG. 4), the third side surface 15d extends from the edge portion (the edge portion on the +X side of the recess 15) connected to the third surface 21A toward the vibrating portion 11 side with a length of h1×tanθ2 (length in plan view). The depth of the recess 15 from the edge portion 21a of the fixed portion 13 in plan view, which is the depth at the height of the third surface 21A, is d1 (FIGS. 3 and 4). When the depth d1 is greater than h1×tanθ2, the bottom surface 15a has an area that is deeper into the fixed portion 13 than the edge portion 21a by the difference d2 (FIGS. 3 and 4) (illustrated example). This area can reduce the influence of vibration reflected by the first side surface 15b and the third side surface 15d, for example. The shape of the region is arbitrary, but is rectangular in the drawing. When the region is rectangular (the illustrated example), d2 is less than d1 when θ2 is greater than 0°. The specific length of d2 is arbitrary. For example, d2 may be 1 / 4×d1 or more and 3 / 4×d1 or less, and may be 1 / 3×d1 or more and 2 / 3×d1 or less. The width w2 of the region is usually shorter than the width w1 of the recess 15 (the width at the height of the third surface 21A). The specific size of w2 is arbitrary. For example, w2 may be 1 / 4×w1 or more and 3 / 4×w1 or less, and may be 1 / 3×w1 or more and 2 / 3×w1 or less. Unlike the illustrated example, the end of the third side surface 15d on the vibration unit 11 side may be located at the edge portion 21a, or may be located closer to the vibration unit 11 than the edge portion 21a.

[0083] The first side surface 15b is inclined at an inclination angle θ3. Therefore, the first side surface 15b extends from the edge portion connected to the third surface 21A (the edge portion on the +Z' side of the recess 15) toward the inside of the recess 15 with a length of h1×tanθ3 (length in plan view) in a plan view. Similarly, the second side surface 15c is inclined at an inclination angle θ4, and extends from the edge portion connected to the third surface 21A (the edge portion on the -Z' side of the recess 15) toward the inside of the recess 15 with a length of h1×tanθ4 (length in plan view) in a plan view. In a plan view, the width of the recess 15 at the height of the third surface 21A of the fixing part 13 is w1 (FIGS. 3 and 5). When the width w1 is greater than the sum of h1×tanθ3 and h1×tanθ4, the first side surface 15b and the second side surface 15c do not directly intersect, and a part of the bottom surface 15a is formed between them (example shown). Examples of the width w2 of the portion have been described above. Unlike the illustrated example, the first side surface 15b and the second side surface 15c may directly intersect with each other.

[0084] As can be understood from the above description, in the illustrated example, the width w1 and the depth d1 are set to be relatively large. For example, the width w1 and / or the depth d1 are larger than the thickness t1 (FIG. 4) of the vibration section 11, the height h1 from the first surface 19A to the third surface 21A, and the length s1 of the fifth surface 23A in a plan view (FIGS. 3 and 4).

[0085] These specific values ​​are arbitrary. Below is an example in which the quartz crystal plate 3 is relatively thin. The thickness t1 may be 16 μm or less. The height h1 may be 16 μm or less or 12 μm or less. The length s1 is, for example, h1×tan θ1, and may be, for example, 17 μm or less or 6 μm or less (however, for example, smaller than the depth d1). On the other hand, the width w1 and / or the depth d1 may be 17 μm or more or 19 μm or more.

[0086] (1.4. Overlap between Extraction Electrode and Recess) In the process from the vibration section 11 (first surface 19A) to the fixed section 13 (third surface 21A), an appropriate portion of the extraction electrode 9 may pass through an appropriate portion of the inner surface of the recess 15. In the illustrated example, the pad portion 9a of the extraction electrode 9 overlaps the entire inner surface of (at least one) of the recess 15. That is, the pad portion 9a overlaps the entire bottom surface 15a, the first side surface 15b, the second side surface 15c, and the third side surface 15d. In other words, the pad portion 9a extends from the bottom surface 15a, which is flush with the first surface 19A, to the three side surfaces via the lower edge portions of the three side surfaces, and further extends from the upper edge portions of the three side surfaces to the third surface 21A.

[0087] Unlike the illustrated example, the wiring portion 9b may overlap the recess 15 (see FIG. 8 described later). Furthermore, the extraction electrode 9 may overlap only a portion of the recess 15. For example, the extraction electrode 9 may overlap all or a portion of the bottom surface 15a, all or a portion of one of the three side surfaces (15c, 15b, and 15d), and not all or at least a portion of at least one of the remaining two side surfaces.

[0088] (1.5. Manufacturing method of crystal element) The crystal element 1 may be manufactured by applying various known manufacturing methods. Although not specifically shown in the drawings, an example of such a method will be described below.

[0089] First, a wafer made of quartz crystal is prepared. The wafer is used to obtain a large number of quartz crystal blanks 3. Such a wafer is cut, for example, at the cutting angle of the AT cut plate described above, and is processed to a thickness equal to that of the fixing portion 13.

[0090] Next, etching masks are formed on both main surfaces of the wafer. These etching masks overlap, for example, the area that will become the quartz crystal plate 3 (the vibration portion 11, the intermediate portion 17, and the fixed portion 13) and the area that will become the frame-shaped portion (waste space) around the multiple quartz crystal plates 3. The wafer is then etched from both main surfaces via the etching masks. The etching is, for example, wet etching in which the wafer is immersed in a chemical solution. This etches the area that will become the quartz crystal plate 3, and the outline of the quartz crystal plate 3 is formed.

[0091] Next, new etching masks are formed on both main surfaces of the wafer. The new etching masks overlap the areas that will become the third surface 21A or the fourth surface 21B (but do not overlap the areas that will become the vibration portion 11, the intermediate portion 17, and the recessed portion 15). The new etching masks may be formed by removing a portion of the previous etching mask.

[0092] Then, the wafer is etched from both main surfaces through a new etching mask. As a result, the region that will become the vibration section 11 becomes thinner than the region that will become the fixed section 13. Furthermore, due to the anisotropy of quartz with respect to etching, a crystal plane appears between the vibration section 11 and the fixed section 13, and an intermediate section 17 that becomes thicker toward the fixed section 13 side is formed between the vibration section 11 and the fixed section 13. Furthermore, a recess 15 is formed by etching. Due to the anisotropy of quartz with respect to etching, the side surface of the recess 15 becomes an inclined surface that inclines in a direction such that the recess 15 becomes larger toward the upper side of the recess 15.

[0093] The etching mask is then removed to form the conductor pattern 5. The conductor pattern 5 may be formed, for example, by depositing a metal film through a mask formed on the surface of the quartz crystal plate 3. Alternatively, the conductor pattern 5 may be formed by depositing a metal film over the entire surface or most of the quartz crystal plate 3, and then etching the metal film through a mask. The film may be formed by an appropriate method such as sputtering.

[0094] After the conductive pattern 5 is formed, the quartz crystal plate 3 is separated (divided) from the frame-shaped portion by, for example, bending or cutting the connection portion with the frame-shaped portion of the wafer. During and / or after singulation, the fixing portion 13 may be used to hold the quartz crystal element 1. For example, the fixing portion 13 may be held by suction, thereby holding the quartz crystal element 1 on a jig.

[0095] (1.6. Summary of quartz crystal elements) As described above, in this embodiment, the crystal element 1 has a piezoelectric plate (crystal plate 3), a first excitation electrode (for example, excitation electrode 7 of the first conductor pattern 5A), and a first extraction electrode (for example, extraction electrode 9 of the first conductor pattern 5A). The crystal plate 3 has a vibration part 11 and a fixed part 13 that constitute different regions from each other in a plan view. The vibration part 11 has a first surface 19A facing the first side (+Y' side) and a second surface 19B facing the second side (-Y' side) opposite to the first side. The fixed part 13 has a third surface 21A facing the +Y' side and a fourth surface 21B facing the -Y' side. The third surface 21A is higher on the +Y' side than the first surface 19A. The excitation electrode 7 overlaps the first surface 19A. The extraction electrode 9 is extracted from the excitation electrode 7 and overlaps the third surface 21A. The quartz crystal plate 3 has a first recess (recess 15 on the +Y' side) recessed from the third surface 21A toward the -Y' side. The recess 15 is formed by cutting out a first edge portion (edge ​​portion 21a) on the first surface 19A side of the third surface 21A in a plan view. The extraction electrode 9 has a portion that extends from the first surface 19A through the recess 15 to the third surface 21A.

[0096] Therefore, for example, the recess 15 can improve the reliability of conduction of the extraction electrode 9. More specifically, this is as follows.

[0097] For example, when forming the conductive pattern 5 by sputtering, a region in the shadow of the fixed portion 13 as seen by metal particles being scattered in a direction including a component of the -X direction may occur on the first surface 19A of the vibrating portion 11 (and the fifth surface 23A of the intermediate portion 17). In the shadowed region, there is a high probability that the extraction electrode 9 will become thin. As a result, the cross-sectional area contributing to the conduction from the vibrating portion 11 to the fixed portion 13 is reduced. When such a reduction in the cross-sectional area occurs, for example, the crystal impedance of the crystal element 1 increases, and the electrical characteristics of the crystal element 1 deteriorate.

[0098] However, when the quartz crystal plate 3 has a recess 15, part of the shaded region shifts toward the fixed portion 13 (+X side). As a result, for example, it becomes easier to attach metal particles to the region that is no longer shaded by the shift. And, for example, a cross-sectional area that contributes to conduction from the vibrating portion 11 to the fixed portion 13 can be secured by a portion of the extraction electrode 9 that extends from the no longer shaded region in a direction that includes a component of the Z' direction to the fifth surface 23A and / or the third surface 21A.

[0099] In addition, for example, the edge 21a of the third surface 21A is likely to have a corner and / or a step. In this case, the extraction electrode 9 is likely to become thin and / or the stress from the quartz crystal plate 3 is likely to be large. As a result, the cross-sectional area contributing to electrical conduction at the edge 21a is likely to be reduced.

[0100] However, by cutting out the edge 21a by the recess 15, for example, the length of the edge of the third surface 21A including the length of the portion recessed by the recess 15 becomes longer, and thus it becomes possible to lengthen the length of the conductor pattern 5 spanning the edge of the third surface 21A (including the edge of the recess 15 in this case). Also, for example, even if a step is formed at the edge 21a (an edge perpendicular to the X-axis in a plan view from another perspective), a step may not be formed at the edge (the upper edge of the first side surface 15b and / or the second side surface 15c) intersecting the edge 21a of the recess 15. In this case, the conductor pattern 5 can reach the third surface 21A from the bottom surface 15a of the recess 15 without passing through the step. For these reasons, it is easy to ensure a cross-sectional area that contributes to conduction.

[0101] Although the effect of improving the reliability of electrical continuity has been exemplified, the recesses 15 also provide other effects, such as the following.

[0102] By forming the recess 15, the fixing portion 13 can reduce the rigidity in a portion on the vibration portion 11 side while ensuring the strength of the fixing portion 13 as a whole. As a result, for example, when the bump 105 (FIG. 7) on which the crystal element 1 is mounted applies distortion to the fixing portion 13, the distortion is absorbed by the portion of the fixing portion 13 on the vibration portion 11 side, and the likelihood of the distortion being transmitted to the vibration portion 11 can be reduced. This reduces the likelihood of the characteristics being deteriorated. The distortion described above is caused, for example, by the cure shrinkage of the bump 105 and / or the warping of the substrate portion 107a (FIG. 7) on which the crystal element 1 is mounted, which will be described later.

[0103] Furthermore, for example, if the entire edge of the fixed part 13 on the vibrating part 11 side were straight, waves arriving at various positions on the edge of the fixed part 13 from the vibrating part 11 would be reflected in the same direction with the same phase, increasing the likelihood that the reflected waves would appear as noise. However, since the recess 15 forms a curved or bent part on the entire edge of the fixed part 13 on the vibrating part 11 side (including the edge of the recess 15 in this case), the direction and / or phase of the reflected waves would be more likely to be dispersed. As a result, noise is reduced.

[0104] The recess 15 may have a crystal plane on a first side surface 15b that intersects with the edge portion 21a in a plan view.

[0105] In this case, for example, the first side surface 15b is formed in a constant direction regardless of errors in the etching conditions. Therefore, it is easy to make the shape of the recess 15 constant in a plurality of crystal elements 1 and reduce the variation in characteristics. Also, the crystal plane tends to appear as an inclined surface that is inclined with respect to the depth direction (Y' direction) of the recess 15. In this case, the following effects can be obtained.

[0106] When the size of recess 15 on the +Y' side in the direction along edge 21a is referred to as the width, first side surface 15b may have an inclined surface that slopes from the bottom of recess 15 to third surface 21A in a direction in which the width of recess 15 increases toward the +Y' side. Extraction electrode 9 may have a portion that extends from the bottom of recess 15 to third surface 21A via the inclined surface.

[0107] In this case, for example, compared to a mode in which the first side surface 15b is perpendicular to the third surface 21A (this mode may also be included in the technology according to the present disclosure), the extraction electrode 9 is more easily formed on the first side surface 15b, and the effect of improving the reliability of the conduction described above is increased. The reason for this is that, in the case of sputtering, metal particles that are blown in the depth direction (Y' direction) of the recess 15 are more likely to adhere to a side surface that is inclined in the depth direction than to a side surface that is parallel to the depth direction. Also, for example, compared to a mode in which the first side surface 15b is perpendicular to the third surface 21A, the likelihood of stress concentration occurring is reduced, and the strength of the fixing part 13 is more likely to be ensured. As described above, the first side surface 15b may directly intersect with the second side surface 15c without the bottom surface 15a being interposed therebetween, and the bottom portion referred to here is not limited to the bottom surface 15a.

[0108] When the size of the recess 15 in the direction along the edge 21a (Z' direction) is referred to as the width, the width w1 of the recess 15 at the height of the third surface 21A (or, from another perspective, the edge 21a) may be greater than the thickness t1 of the vibration section 11.

[0109] In this case, it can be said that the width w1 is relatively large. As a result, for example, the above-mentioned various effects are improved. For example, it is easier to secure the area of ​​the region in the shadow of the fixed part 13 that is shifted toward the fixed part 13 in the Z' direction. As a result, for example, it is easier to secure the cross-sectional area that contributes to conduction. Also, for example, the effect of reducing the distortion of the vibrating part 11 is improved. Also, a crystal plane is more likely to appear on the first side surface 15b, and the bottom surface 15a is more likely to intrude into the fixed part 13 side (the first side surface 15b and the second side surface 15c are less likely to directly intersect). The effect of the bottom surface 15a intruding into the fixed part 13 side will be described later.

[0110] In the AT-cut crystal element 1, the thickness t1 is a parameter that determines the frequency. Therefore, the width w1, which is determined in comparison with the thickness t1, is expected to have the same effect in AT-cut crystal elements 1 of various sizes. The same is true for the depth d1.

[0111] The depth d1 of the recess 15 from the edge 21a in a plan view, which is the depth at the height of the third surface 21A (the edge 21a from another point of view), may be larger than the thickness t1 of the vibration section 11.

[0112] In this case, it can be said that the depth d1 is relatively large. As a result, for example, the above-mentioned various effects are improved. For example, the shift amount of the region that is shifted toward the fixed part 13 among the regions that are in the shadow of the fixed part 13 can be increased, or the length from the region that was not originally in the shadow to the shifted region can be increased. As a result, for example, it is easier to ensure a cross-sectional area that contributes to conduction. In addition, for example, a crystal plane is more likely to appear on the third side surface 15d, and the bottom surface 15a is more likely to intrude into the fixed part 13 side (the third side surface 15d is less likely to exceed the edge portion 21a toward the vibration part 11 side). The effect of the bottom surface 15a intruding into the fixed part 13 side will be described later.

[0113] When the size of the recess 15 in the direction along the edge 21a (Z' direction) is referred to as the width, the width w1 of the recess 15 at the height of the third surface 21A (or, from another perspective, the edge 21a) may be greater than the height h1 from the first surface 19A to the third surface 21A (edge ​​21a).

[0114] In this case, it can be said that the width w1 is relatively large. The effect of the width w1 being relatively large is as described above. Also, when the height h1 is large, for example, the probability of a shadow being generated inside the recess 15 increases. However, by making the width w1 relatively large with respect to the height h1, it is possible to reduce the probability of a shadow being generated when viewed in a direction including a component of the Z' direction. As a result, for example, it becomes easier to form a metal film inside the recess 15, and the effect of improving the reliability of conduction is increased.

[0115] The depth d1 from the edge 21a of the recess 15 in a plan view, which is the depth at the height of the third surface 21A (or from another perspective, the edge 21a), may be greater than the height h1 from the first surface 19A to the third surface 21A (edge ​​21a).

[0116] In this case, it can be said that the depth d1 is relatively large. The effect of making the depth d1 relatively large is as described above. Also, when the height h1 is large, for example, the probability of a shadow being generated inside the recess 15 increases. However, by making the depth d1 relatively large with respect to the height h1, it is possible to reduce the probability of a shadow being generated when viewed in a direction including a component of the X-direction. As a result, for example, it becomes easier to form a metal film inside the recess 15, and the effect of improving the reliability of conduction is increased.

[0117] The inner surface of the recess 15 may have a bottom surface 15a and an end surface (third side surface 15d). The bottom surface 15a may be connected to the first surface 19A and may be flush with the first surface 19A. The third side surface 15d may be located on the opposite side (+X side) of the first surface 19A with respect to the bottom surface 15a in a plan view, and may rise from the bottom surface 15a to the third surface 21A (edge ​​portion 21a) while being inclined in a direction approaching the height of the third surface 21A (edge ​​portion 21a from another point of view) as it moves away from the bottom surface 15a in a plan view. In a plan view, the bottom surface 15a may be recessed closer to the third surface 21A than the edge portion 21a.

[0118] In this case, for example, the extraction electrode 9 can have a portion that is flush from the first surface 19A to the bottom surface 15a, and a portion that extends from the bottom surface 15a to the third surface 21A via the first side surface 15b or the second side surface 15c. In other words, the extraction electrode 9 can have a portion that extends from the first surface 19A to the third surface 21A, avoiding the edge portion 21a and an edge portion (the boundary between the third side surface 15d and the third surface 21A) facing the same direction as the edge portion 21a. As a result, even if the extraction electrode 9 becomes thin at the edge portion 21a and an edge portion similar to the edge portion 21a, for example, the reliability of conduction can be ensured.

[0119] The quartz crystal plate 3 may have a fifth surface 23A that connects the first surface 19A and the third surface 21A (or from another perspective, the edge 21a) and is inclined so as to be located on the first side (+Y' side) closer to the third surface 21A (edge ​​21a). When the size of the recess 15 in the direction along the edge 21a (Z' direction) is referred to as the width, the width w1 of the recess 15 at the height of the third surface 21A (edge ​​21a) may be larger than the length s1 (length in the X direction) of the fifth surface 23A from the first surface 19A to the third surface 21A (edge ​​21a) in a plan view.

[0120] In this case, it can be said that the width w1 is relatively large. The effect of making the width w1 relatively large is as described above. Also, assuming that the overall length (X direction) of the quartz crystal plate 3 and the length in the X direction of the fixed portion 13 are constant, when the length s1 is long, the area of ​​the vibrating portion 11 is reduced by the intermediate portion 17. As a result, for example, the degree to which the vibration of the vibrating portion 11 is restricted by the intermediate portion 17 and the fixed portion 13 increases, and the characteristics may deteriorate. However, by increasing the width w1 of the recess 15, the volume of the intermediate portion 17 can be substantially reduced, thereby reducing the likelihood of such inconvenience occurring.

[0121] The depth d1 from the edge 21a of the recess 15 in plan view, which is the height of the third surface 21A (the edge 21a in another view), may be larger than the length s1 of the fifth surface 23A from the first surface 19A to the third surface 21A (the edge 21a) in plan view. In this case, it can be said that the depth d1 is relatively large. The effect of making the depth d1 relatively large is as described above. In addition, when the length s1 is long, the third side surface 15d having a length equivalent to the length s1 also becomes long. In addition, it becomes difficult to extend the bottom surface 15a to the third surface 21A side (+X side). However, by making the depth d1 relatively large with respect to the length s1, the likelihood of such inconvenience occurring can be reduced.

[0122] In plan view, the recess 15 may entirely overlap the extraction electrode 9.

[0123] In this case, for example, the reliability of conduction is further improved. For example, even if a shadow is cast on a part of the inner surface of the recess 15 as seen from a metal particle that is thrown in a predetermined direction, a film is formed on another part of the inner surface of the recess 15, so that the cross-sectional area of ​​conduction can be secured. Also, even if a step is generated at the boundary between any side surface of the recess 15 and the third surface 21A, making the lead electrode 9 prone to becoming thin, it is expected that such a problem will not occur at the boundary between the other side surface and the third surface 21A.

[0124] The crystal element 1 may have a second excitation electrode (excitation electrode 7 of the second conductor pattern 5B) overlapping the second surface 19B, and a second extraction electrode (extraction electrode 9 of the second conductor pattern 5B) drawn from the second excitation electrode and overlapping the fourth surface 21B. The fourth surface 21B may be higher on the -Y' side than the second surface 19B. The crystal blank 3 may have a second recess (recess 15 on the -Y' side) recessed from the fourth surface 21B to the +Y' side. The second recess may be a cutout of the edge 21a of the fourth surface 21B on the second surface 19B side in a plan view. The second extraction electrode may have a portion extending from the second surface 19B to the fourth surface 21B via the second recess.

[0125] That is, the fixed portion 13 is higher on both sides in the thickness direction than the vibrating portion 11, not just on one side, and has recesses 15 on both sides. In this case, for example, the various effects described above due to the recesses 15 can be obtained on both sides of the quartz crystal plate 3. Also, for example, the distribution of vibration in the vibrating portion 11 can be made equal on both sides, reducing the likelihood of unintended peculiar vibrations occurring.

[0126] In plan view, the vibrating section 11 may be rectangular. In plan view, the edge 21a of the third surface 21A may be along any one of the four sides (one side on the +X side in this embodiment) of the vibrating section 11. In plan view, assuming a virtual line (center line CL) of the vibrating section 11 perpendicular to the one side, the multiple recesses 15 may be positioned line-symmetrically with respect to the center line CL.

[0127] In this case, for example, the multiple recesses 15 improve the various effects described above (for example, the effect of improving the reliability of conduction). In addition, for example, the distribution of strain generated in the vibrating part 11 can be made symmetrical with respect to the center line CL. The reason for this is, for example, that the vibration leaking from the vibrating part 11 to the fixed part 13 and being reflected is made symmetrical, and / or that the strain applied to the vibrating part 11 from the two bumps 105 via the fixed part 13 is made symmetrical. By improving the symmetry of the strain distribution, for example, the probability of unintended peculiar vibration occurring is reduced, and the electrical characteristics of the crystal element 1 are improved.

[0128] The depth of the recess 15 from the third surface 21A at the end of the recess 15 on the vibration portion 11 side in a planar view may be 50% or more and 100% or less of the height h1 from the first surface 19A to the third surface 21A (100% in the illustrated example).

[0129] When the depth of the recess 15 is 50% or more of the height h1, for example, there is a high probability that the effect of shifting the above-mentioned shadow region toward the fixed part 13 is achieved. Also, when the depth of the recess 15 is 100% or less of the height h1, for example, it becomes easier to maintain the strength of the fixed part 13.

[0130] In the above embodiment, the crystal element 1 is an example of a piezoelectric vibration element. The crystal blank 3 is an example of a piezoelectric blank. The +Y' side is an example of a first side. The -Y' side is an example of a second side. The excitation electrode 7 of the first conductor pattern 5A is an example of a first excitation electrode. The extraction electrode 9 of the first conductor pattern 5A is an example of a first extraction electrode. The recess 15 on the +Y' side is an example of a first recess. The edge 21a on the +Y' side is an example of a first edge. The first side surface 15b is an example of a side surface. The third side surface 15d is an example of an end surface. The excitation electrode 7 of the second conductor pattern 5B is an example of a second excitation electrode. The extraction electrode 9 of the second conductor pattern 5B is an example of a second extraction electrode. The recess 15 on the -Y' side is an example of a second recess. The edge 21a on the -Y' side is an example of a second edge.

[0131] (2. Example of use of crystal element 1) Fig. 6 is a perspective view of a quartz crystal device 101 as an example of use of the quartz crystal element 1. Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 6. Note that the quartz crystal device 101 may be oriented in either a vertical or horizontal direction, but in the following description, for convenience, the upper side of the paper in Figs. 6 and 7 may be referred to as the upper side, and terms such as "top surface" may be used.

[0132] The crystal device 101 is, for example, an electronic component that has a generally rectangular parallelepiped shape. The dimensions of the crystal device may be any appropriate size. For example, the length of the long or short side is 0.6 mm or more and 2.0 mm or less, and the thickness in the vertical direction is 0.2 mm or more and 1.5 mm or less. The crystal device 101 is, for example, surface-mounted with its bottom surface facing the top surface of a mounting base (e.g., a circuit board) (not shown).

[0133] The crystal device 101 is configured as, for example, an oscillator that contributes to the generation of an oscillation signal in which the signal strength (for example, voltage and / or current) oscillates at a certain frequency. The crystal device 101 includes, for example, a crystal element 1 that generates the vibration used to generate the oscillation signal, and a package 103 that packages the crystal element 1.

[0134] The package 103 has, for example, a base 107 that supports the crystal element 1, and a lid 109 that is bonded to the base 107 and seals the crystal element 1. The crystal element 1 is supported by being bonded to the base 107 by, for example, conductive bumps 105. The internal space of the package 103 is, for example, a vacuum or filled with an appropriate gas (for example, nitrogen).

[0135] The base 107 is shaped to have, for example, a recess for accommodating the crystal element 1. From another perspective, the base 107 has a flat substrate portion 107a and a frame portion 107b that runs along the edge of the upper surface of the substrate portion 107a. The base 107 consisting of the substrate portion 107a and the frame portion 107b is made of an insulating material such as a ceramic material. The lid 109 is made of, for example, a metal, and is joined to the upper surface of the frame portion 107b by seam welding or the like.

[0136] The package 103 has conductors for electrically connecting the crystal element 1 and a mounting base (not shown) on which the crystal device 101 is mounted. For example, the package 103 has pads 111 for mounting the crystal element 1, external terminals 113 for mounting the crystal device 101 on a mounting base, and wiring conductors (not shown) for connecting the two.

[0137] The pads 111 are formed of a conductive layer located on the upper surface of the substrate portion 107a. The external terminals 113 are formed of a conductive layer located on the lower surface of the substrate portion 107a. The wiring conductors (not shown) are formed to include through conductors that vertically penetrate the substrate portion 107a. The material of these conductors is, for example, a metal.

[0138] The crystal element 1 is bonded to the pad 111 by the bump 105. As a result, the crystal element 1 is supported by the base 107 and electrically connected to the package 103. More specifically, the crystal element 1 is bonded to the pad 111 at, for example, one end thereof and supported in a cantilever shape. The bump 105 is made of, for example, a conductive adhesive. The conductive adhesive is made of a thermosetting resin mixed with a metal filler.

[0139] The external terminals 113 are joined to pads of a mounting substrate (not shown) by soldering, for example, so that the crystal device 101 is supported and electrically connected to the mounting substrate.

[0140] The quartz crystal element 1 may be used in various other ways in addition to the above-mentioned examples of use.

[0141] For example, a crystal device (piezoelectric device) including the crystal element 1 may be an oscillator having, in addition to the crystal element 1, an integrated circuit element (IC: Integrated Circuit) that applies a voltage to the crystal element 1 to generate an oscillation signal. Also, for example, the vibrator may have other electronic elements such as a thermistor in addition to the crystal element 1. Also, the piezoelectric device may be equipped with a thermostatic oven.

[0142] In the piezoelectric device, the structure of the package that packages the crystal element 1 may be appropriately configured. For example, the package may have an H-shaped cross section with recesses on the upper and lower surfaces. The package may also be configured with a substrate-like base body (a base body without a recess) and a cap-like lid body that covers the base body.

[0143] (3. Other Examples) Various examples will be described below with reference to Figures 8 to 10. In the following description, basically, only the differences from the embodiment will be described. Matters that are not specifically mentioned may be considered to be the same as the embodiment or may be inferred from the embodiment.

[0144] (3.1. Other Examples of Extraction Electrodes and Recesses) FIG. 8 is a plan view of a crystal element 201 according to another example, viewed from the +Y' side.

[0145] The extraction electrode 209 of the crystal element 201 has a pad portion 209a and a wiring portion 209b, similar to the extraction electrode 9 of the embodiment. However, the wiring portion 209b is formed longer than the wiring portion 9b of the embodiment, and overlaps not only the vibration portion 11 but also the intermediate portion 17 and the fixed portion 13. On the fixed portion 13, the relative relationship between the length of the wiring portion 209b in the X direction and the length of the pad portion 209a in the X direction is arbitrary. For example, the former may be longer than the latter (example shown in the figure), may be equal to the latter, or may be shorter.

[0146] The plan view of the crystal element 201 seen from the -Y' side may be the same as that shown in FIG. 8, for example, or may not be the same. In other words, the former means that the crystal element 201 may have a configuration that is 180° rotationally symmetrical with respect to a center line (not shown) parallel to the X direction. An example of the latter is a mode in which the pad portion 209a (not shown) on the -Y' side is larger in the X direction than the pad portion 209a on the +Y' side shown in FIG. 8. In this case, the crystal element 201 is mounted on the package 103, for example, so that the pad portion 209a on the -Y' side faces the pad 111 of the package 103. At this time, the pad portion 209a on the +Y' side is not necessarily bonded to the bump 105 (contributes to mounting). However, for convenience, even in the above mode, the portion that is wider than the wiring portion 209b on the +Y' side is referred to as the pad portion 209a.

[0147] The crystal element 201 has a recess 215 in the fixed portion 13, as in the embodiment. The extraction electrode 209 overlaps at least a portion (all of the recess in the illustrated example) of the recess 215. However, in this example, at least a portion (all of the recess in the illustrated example) of the recess 215 overlaps the wiring portion 209b. As described above, the pad portion 209a on the -Y' side may be larger in the X direction than the pad portion 209a on the +Y' side. In this case, unlike the +Y' side, the pad portion 209a on the -Y' side may overlap a part or all of the recess 215.

[0148] In the illustrated example, the third surface 21A has only one recess 215 for one conductor pattern 205 (first conductor pattern 205A in FIG. 8). However, the wiring portion 209b is not in the recess. 2 In a mode where the third surface 21A overlaps with the wiring portion 209b, similarly to the embodiment, the third surface 21A may have one or more recesses 215 in each of the first conductor pattern 205A and the second conductor pattern 205B. Also, the third surface 21A may have two or more recesses 215 in only one conductor pattern 205. In the illustrated example, the recesses 215 are formed to be elongated in a plan view. However, the shape and dimensions of the recesses 215 overlapping with the wiring portion 209b are arbitrary, similar to the shape and dimensions of the recesses 15 in the embodiment. Note that the recesses on the third surface 21A 2 15 is a recess on the fourth surface 21B 2 As already mentioned, the above may be incorporated into the explanation of 15.

[0149] As described above, the first extraction electrode (the extraction electrode of the first conductor pattern 205A) 20 9) may have a wiring portion 209b and a pad portion 209a. The wiring portion 209b may extend from the first excitation electrode (excitation electrode 7 of the first conductor pattern 205A). The pad portion 209a may be connected to the wiring portion 209b and may be wider than the wiring portion 209b in a direction along the edge portion 21a of the fixed portion 13 on the vibration portion 11 side. The first recess (recess 215 on the +Y' side) may have a portion overlapping the wiring portion 209b in a plan view.

[0150] In this case, for example, the wiring portion 209b is smaller in width than the pad portion 209a, and therefore it is relatively difficult to secure a cross-sectional area for conduction, so the effect of improving the reliability of conduction by the recess 215 is useful. Also, on the premise that the wiring portion 209b and the recess 215 overlap, the wiring portion 209b extends across from the vibrating portion 11 to the fixed portion 13, improving the degree of freedom of the fixing position of the crystal element 201 and the package 103. This reduces the effect of mounting the crystal element 201 on the package 103 on the vibration of the vibrating portion 11, for example.

[0151] (3.2. Other examples of fixing part positions) 9A and 9B are plan views of another example of a quartz crystal plate. In the embodiment, the fixing portion 13 is shaped to follow one side of the rectangular vibrating portion 11. However, the fixing portion may follow two or more sides of the vibrating portion. The quartz crystal plate in FIG. 9A and FIG. 9B has such a fixing portion that extends over two or more sides. Specifically, it is as follows.

[0152] As described above, the vibration section 11 does not have to be rectangular, and may be circular or the like. On the other hand, the term "side" is usually used for polygons. However, in the description of the embodiment, for convenience, the term "side" may be used when describing the position of the fixed section 13 relative to the vibration section 11. One side can be rephrased as an edge portion located on one side of a predetermined direction with respect to the vibration section 11. Two sides facing each other can be rephrased as, for example, two edges facing each other, or two edges located on both sides of a predetermined direction with respect to the vibration section 11. In addition, two sides intersecting each other can be rephrased as, for example, two edges intersecting each other, or a combination of an edge portion located on one side of a first direction with respect to the vibration section 11 and an edge portion located on one side of a second direction perpendicular to the first direction with respect to the vibration section 11.

[0153] The quartz crystal blank 303 shown in FIG. 9A has a fixed portion 313 (and an intermediate portion 317) along two sides of the vibrating portion 311. In other words, the fixed portion 313 is formed in an L shape. Instead of regarding the fixed portion 313 as being configured in an L shape, the quartz crystal blank 303 may be regarded as having a total of two linear fixed portions 313. In the following description, for convenience, the portion of the fixed portion 313 that is along one side of the vibrating portion 311 may be referred to as one side of the fixed portion 313, etc.

[0154] The recesses 315 corresponding to the recesses 15 of the embodiment are located, for example, on each of two sides of the fixed portion 313. However, the recesses 315 may be located on only one side. In the illustrated example, on each side, the multiple recesses 315 are arranged symmetrically with respect to the center line of the vibration portion 311 perpendicular to each side. Of course, the arrangement of the multiple recesses 315 may be asymmetric.

[0155] The quartz crystal plate 403 shown in FIG. 9B has fixed portions 413 (and intermediate portion 417) along three sides of the vibrating portion 411. In other words, the fixed portions 413 are formed in a U-shape. Instead of regarding the fixed portions 413 as being configured in a U-shape, the quartz crystal plate 403 may be regarded as having a total of three linear fixed portions 413. In the following description, for convenience, a portion of the fixed portion 413 that is aligned along one side of the vibrating portion 411 may be referred to as one side of the fixed portion 413, etc.

[0156] The recesses 415 corresponding to the recesses 15 in the embodiment are located, for example, on each of the three sides of the fixed portion 413. However, the recesses 415 may be located on only one side or only two sides. In the illustrated example, on each side, the multiple recesses 415 are arranged symmetrically with respect to the center line of the vibration portion 411 perpendicular to each side. Of course, the arrangement of the multiple recesses 415 may be asymmetric.

[0157] The fixing portion may be located along the four sides of the vibrating portion (FIG. 11, described later). A quartz crystal element having fixing portions along two or more sides of the vibrating portion may be supported in a cantilever shape with only one side fixed to the package 103, as in the embodiment, or may be supported by being fixed to the package 103 at two or more sides. The shape and / or size of the fixing portion (and / or intermediate portion) on the sides may be the same as each other, or may be different from each other. For example, the width of the fixing portion on the side having the pad portion 9a, not shown here, may be larger than the width of the fixing portion on the other sides. In these examples, the portion of the extraction electrode that overlaps with the recess may be a wiring portion or a pad portion, or such a distinction may not be possible. The side on which the wiring portion extends from the vibrating portion to the fixing portion may be different from the side on which the pad portion is located.

[0158] (3.3. Other examples of thickness of fixing part) FIG. 10 is a cross-sectional view showing the configuration of a crystal element 501 according to another example, and corresponds to a part of FIG.

[0159] In the quartz crystal plate 503 of the quartz crystal element 501, the fixed portion 513 (and the intermediate portion 517) is higher than the vibrating portion 511 on only one side in the thickness direction of the quartz crystal plate 503. Although not shown here, a recess corresponding to the recess 15 is formed on only the one side of the fixed portion 513.

[0160] (Chapter 2 Second Embodiment) (1. Overview of quartz crystal elements) The crystal element 601 according to the second embodiment will be described below with reference to FIGS. 11 and 12. In the following description, basically, only the differences from the first embodiment (and other examples according to the first embodiment; the same applies below) will be described. Matters that are not specifically mentioned may be considered to be the same as the first embodiment or may be inferred from the first embodiment. The description of the first embodiment may be used in the second embodiment as long as no contradiction or the like occurs. The description of the second embodiment may be used in the first embodiment as appropriate. The specific configuration of the crystal element 601 may be other than those exemplified in FIGS. 11 and 12, but for convenience, the description may be given on the premise of the specific configuration shown in the figures without any special mention.

[0161] Fig. 11 is a perspective view of the quartz crystal element 601. Fig. 12 is a cross-sectional view taken along line XII-XII in Fig. 11. The quartz crystal element 601 is configured, for example, to be rotationally symmetrical by 180° with respect to a center line (not shown; see center line CL in Fig. 2 according to the first embodiment) parallel to the X-axis. Therefore, the perspective view of the quartz crystal element 601 viewed from the -Y' side is the same as Fig. 11.

[0162] 11 and 12 show the shape of the quartz crystal element 601 more typically than FIG. 1 of the first embodiment. Specifically, in these figures, the inclined surfaces caused by the anisotropy of quartz crystal with respect to wet etching are omitted. Furthermore, the portion corresponding to the intermediate portion 17 of the first embodiment is omitted, and the inclined surfaces inside the recess and through hole (described later) are also omitted. These portions and inclined surfaces may exist as in the first embodiment. However, as shown in the figures, such portions and inclined surfaces may not exist.

[0163] The quartz crystal plate 603 of the quartz crystal element 601 has a vibrating portion 611 and a fixed portion 613, similar to the quartz crystal plate 3 of the first embodiment. However, unlike the first embodiment, the fixed portion 613 has an inner portion 613a and an outer portion 613b that have different thicknesses. The inner portion 613a is adjacent to the vibrating portion 611 (with or without an intermediate portion (not shown) in between). The outer portion 613b is located on the opposite side of the vibrating portion 611 with respect to the inner portion 613a, and is thicker than the inner portion 613a. In other words, the thickness of the fixed portion 613 changes in stages so that it becomes thicker the further away from the vibrating portion 611 it is.

[0164] In this case, for example, it is easy to ensure the thickness of the outer part 613b. As a result, the effect of making the fixed part 613 thicker than the vibrating part 611 is improved. For example, the effect is that the strength of the outer part 613b is improved. When the strength of the outer part 613b is improved, for example, the probability that the crystal plate 603 is deformed when the outer part 613b is sucked and held during the manufacturing process is reduced. From another perspective, the step between the vibrating part 611 and the inner part 613a and the step between the inner part 613a and the outer part 613b can be reduced. This reduces the probability that the lead electrode 609 is broken at the step. In addition, for example, compared to a mode in which the outer part 613b is connected to the vibrating part 611 without the inner part 613a, the action of the fixed part 613 restricting the vibration of the vibrating part 611 is reduced, and the vibration characteristics are improved.

[0165] As described in Chapter 1, Section 3.2, etc., the position of the fixed part 613 relative to the vibrating part 611 is arbitrary. In the example of Fig. 11, the fixed part 613 is located along the four sides of the vibrating part 611 (from another point of view, it surrounds the vibrating part 611). Therefore, an edge 621a (corresponding to the edge 21a in the first embodiment) of the fixed part 613 on the vibrating part 611 side is rectangular and forms four corners. Then, a recess 615A corresponding to the recess 15 in the first embodiment is located at at least one of the four corners (all in the illustrated example).

[0166] In this case, for example, since the extraction electrode 609 extends from the excitation electrode 607 toward the corner, the influence of the extraction electrode 609 on vibration is reduced, although it depends on the vibration mode used, etc. Also, by connecting the side surface of the recess 615A and the side surface of the inner portion 613a that are along the same direction (X direction in the illustrated example), the side surface of the recess 615A can be substantially extended. As a result, the conductive area of ​​the extraction electrode 609 passing through the side surface of the recess 615A can be secured, and the reliability of the conduction can be improved.

[0167] The quartz crystal plate 603 has a recess 615A located between the vibrating portion 611 and the fixed portion 613 (inner portion 613a), and also has a recess 615B located between the inner portion 613a and the outer portion 613b. The effects of this will be described later. Each of the conductor patterns 605 (605A and 605B) of the quartz crystal element 601 has two extraction electrodes 609 on both sides of the excitation electrode 607 in the X direction. The effects of this will be described later.

[0168] The above is an outline of the differences between the first and second embodiments. Each part will be described in detail below.

[0169] (2. Crystal base plate) (2.1. Entire quartz crystal substrate and vibrating part) The description of the entire quartz crystal plate 3 and the vibrating portion 11 according to the first embodiment may be applied to the entire quartz crystal plate 603 and the vibrating portion 611 according to the second embodiment. To be sure, the quartz crystal plate 603 may be, for example, an AT-cut quartz crystal piece, as in the first embodiment. The planar shape of the quartz crystal plate 603 and the planar shape of the vibrating portion 611 are arbitrary. In the above-mentioned description of the outline of the second embodiment, it was described that the recess 615A is formed at the corner of the edge portion 621a (the vibrating portion 611 from another point of view). However, other features may be extracted from the second embodiment. In this case, it is not necessary for the vibrating portion 611 to have a corner. Therefore, as described in the description of the first embodiment, the vibrating portion 611 may be, for example, circular or elliptical. As described in the description of the first embodiment, the length in the X direction and the length in the Z' direction of the entire quartz crystal plate 603 or the vibrating portion 611 may be the same or different. In the latter case, either length may be longer than the other length.

[0170] To be more specific, in the explanation of the first embodiment, with reference to Fig. 10, it has been stated that the main surface of the fixed portion 513 may be higher than the main surface of the vibrating portion 511 only on one side in the thickness direction of the quartz crystal plate 503. This is also the case in the second embodiment. However, as mentioned above, for convenience, the configuration of the quartz crystal plate 603 may be explained here using the configuration shown in the figure as an example without any particular notice.

[0171] (2.2. Fixed part) The description of the fixed portion 13 in the first embodiment may be applied to the fixed portion 613 in the second embodiment. In the description of the outline of the second embodiment, it was described that the recess 615A is formed at the corner of the edge portion 621a. However, other features may be extracted from the second embodiment. In this case, the fixed portion 613 does not need to be located on two sides (four sides in the example of FIG. 11) of the vibration portion 611. Therefore, as described in the description of the first embodiment, the fixed portion 613 may be located, for example, on only one side, only two sides, only three sides, or only four sides of the vibration portion 611. Also, in the description of the outline of the second embodiment, it was described that the fixed portion 613 has an inner portion 613a and an outer portion 613b. However, other features may be extracted from the second embodiment. In this case, the fixed portion 613 does not need to have portions having different thicknesses. Therefore, for example, the shape of the fixed portion 613 may be the same as that of the first embodiment.

[0172] Hereinafter, the shape of the fixed portion 613 having the inner portion 613a and the outer portion 613b will be described. To be sure, even in the case where the fixed portion 613 has the inner portion 613a and the outer portion 613b, the description of the fixed portion 13 according to the first embodiment may be applied to the fixed portion 613, unless a contradiction occurs. Furthermore, the description of the fixed portion 13 according to the first embodiment may be applied to the second embodiment by replacing the term fixed portion 13 with the term inner portion 613a or the term outer portion 613b, unless a contradiction occurs. When replacing the term fixed portion 13 with the term outer portion 613b, the term vibration portion 11 may simply be replaced with the vibration portion 611, or, unlike the description here, the vibration portion 611 and the inner portion 613a may be regarded as parts corresponding to the vibration portion 11 of the first embodiment.

[0173] In the following explanation, for convenience, the +Y' side surface (first surface 619A and third surface 621A) and the -Y' side surface (second surface 619B (FIG. 12) and fourth surface 621B) of the quartz crystal substrate 603 will be used as an example. The configuration of the -Y' side surface may be the same as that of the +Y' side surface, for example.

[0174] As described above, the outer portion 613b is thicker than the inner portion 613a. From another perspective, the third surface 621A of the fixing portion 613 has a first region 622A (the upper surface of the inner portion 613a) and a second region 622B (the upper surface of the outer portion 613b) that is higher on the +Y' side than the first region 622A. The first region 622A has an edge portion 621a that is cut out by the recess 615A described above. The second region 622B has an edge portion 621b that is cut out by the recess 615B described above.

[0175] The description of the third surface 21A in the first embodiment may be applied to each of the first region 622A and the second region 622B, unless a contradiction occurs. Therefore, for example, the first region 622A and the second region 622B are planar parallel to the XZ' plane and / or the first surface 619A of the vibration section 611. In other words, the first region 622A and the second region 622B have different heights in a stepwise (step-like) manner. From this viewpoint, the fifth surface 23A (the middle portion 17 from another viewpoint) and the first region 622A (the inner portion 613a from another viewpoint) shown in the description of the first embodiment may be distinguished.

[0176] The first embodiment can be understood as an embodiment in which the top surface of the quartz crystal plate 3 has a single-step change (more specifically, a change that becomes higher) from the vibrating portion 11 to the fixed portion 13. The second embodiment can be understood as an embodiment in which the top surface of the quartz crystal plate 603 has a two-step change (more specifically, a change that becomes higher on both sides) from the vibrating portion 611 to the fixed portion 613. Conceptualized further, the second embodiment can be understood as an embodiment in which the top surface of the quartz crystal plate 603 has a multiple-step change (for example, a change that becomes higher on both sides) from the vibrating portion 611 to the fixed portion 613. The multiple steps are not limited to two steps, and may be three or more steps.

[0177] As can be understood from the above description, the inner portion 613a may be located on only one side, only two sides, only three sides, or only four sides of the vibrating portion 11. In the illustrated example, the inner portion 613a is located on four sides (from another perspective, it surrounds the vibrating portion 611). Similarly, the outer portion 613b may be located on only one side, only two sides, only three sides, or only four sides of the vibrating portion 611. In the illustrated example, the outer portion 613b is located on two sides that face each other with the vibrating portion 611 (and the inner portion 613a) in between in a predetermined direction (in other words, it has two parts that face each other with the vibrating portion 611 in between). More specifically, the above-mentioned predetermined direction is, for example, the X direction (from another perspective, the direction of thickness-shear vibration). In the illustrated example, the outer portion 613b is entirely connected to the vibration portion 611 via the inner portion 613a, and does not have a portion that is connected to the vibration portion 611 without passing through the inner portion 613a.

[0178] The arrangement of the inner part 613a and the outer part 613b in the circumferential direction of the vibration part 611 is possible in various ways other than the illustrated example. Some examples are given below. For example, the arrangement positions of the inner part 613a and the outer part 613b may be the same as each other. That is, the inner part 613a and the outer part 613b may be located on only one side, only two sides, only three sides, or only four sides of the vibration part 611. Also, for example, contrary to the illustrated example, the arrangement range of the outer part 613b may be wider than the arrangement range of the inner part 613a. For example, the inner part 613a may be located on two sides on both sides in the X direction, while the outer part 613b may be located on four sides. In this case, both sides of the outer part 613b in the Z' direction may be connected to the vibration part 611 without the inner part 613a.

[0179] The relative sizes of the vibration part 611, the first region 622A, and the second region 622B in a plan view are arbitrary. For example, in the direction in which the first region 622A and the second region 622B are arranged (X direction in the illustrated example), the length of the first region 622A and the length of the second region 622B may be the same or different. When they are different, either of the former length and the latter length may be relatively larger. The length of each of the first region 622A and the second region 622B on one side (or both sides) of the vibration part 611 in the above-mentioned arrangement direction, or the total length, may be the same or different with respect to the length of the vibration part 611. When they are different, either of the former length and the latter length may be relatively larger. In the illustrated example, the length of the first region 622A is shorter than the length of the second region 622B in the X direction (the above-mentioned arrangement direction). In addition, in the X direction, the length of vibrating part 611 is longer than both a portion of first region 622A located on one side in the X direction and a portion of second region 622B located on one side in the X direction, and is longer than the sum of both of them. On the other hand, in the X direction, the length of vibrating part 611 is shorter than the total length of both sides in the X direction of fixed part 613.

[0180] The thickness of each part of the quartz crystal plate 603 is arbitrary. For example, the thickness of the vibration part 611 is set according to the intended resonance frequency, as in the first embodiment. As already described, the explanation of the thickness of the fixed part 13 described in the first embodiment may be applied to the thickness of the inner part 613a and / or the thickness of the outer part 613b, unless a contradiction occurs. The explanation of the height from the first surface 19A to the third surface 21A in the first embodiment may be applied to the height from the first surface 619A to the first region 622A and / or the height from the first region 622A to the second region 622B, unless a contradiction occurs. The relationship between the height from the first surface 619A to the first region 622A and the height from the first region 622A to the second region 622B (in other words, the relationship between a plurality of heights when the height changes stepwise) is arbitrary. For example, the two may be the same or different. When they are different, either the former or the latter may be relatively larger.

[0181] (2.3. Other) As described above, although not shown in Figs. 11 and 12, a portion corresponding to the intermediate portion 17 of the first embodiment may be present between the vibration portion 611 and the fixed portion 613. That is, an inclined surface (corresponding to the fifth surface 23A) may be present between the first surface 619A and the third surface 621A (from another point of view, the first region 622A or the edge portion 621a). In addition to (or instead of) between the vibration portion 611 and the fixed portion 613, a portion corresponding to the intermediate portion 17 may also be present between the inner portion 613a and the outer portion 613b (from another point of view, between adjacent portions in the case where the thickness changes stepwise). That is, an inclined surface (corresponding to the fifth surface 23A) may be present between the first region 622A and the second region 622B (from another point of view, the edge portion 621b).

[0182] To repeat, the description of the intermediate portion 17 according to the first embodiment may be applied to the intermediate portion between the vibrating portion 611 and the fixed portion 613, unless a contradiction occurs. The description of the intermediate portion 17 according to the first embodiment may be applied to the intermediate portion between the inner portion 613a and the outer portion 613b. In this case, the description of the intermediate portion 17 may be applied by regarding the combination of the vibrating portion 611 and the inner portion 613a as the vibrating portion 11 and the outer portion 613b as the fixed portion 13. Just to be clear, the inclination angle of each intermediate portion is arbitrary, and the intermediate portion may or may not be planar.

[0183] When the quartz crystal plate 603 is an AT-cut quartz crystal piece, the inclination angle θ1 of the intermediate portion 17 in the first embodiment may be used for the inclination angle of the intermediate portion located on the +X side or the -X side with respect to the vibrating portion 611 (or the inner portion 613a). For example, the inclination angle of the intermediate portion on the +X side is about 55° (e.g., 53° to 57°). The inclination angle of the intermediate portion on the -X side is about 27° (e.g., 25° to 29°). The above description applies to both the +Y' side and the -Y' side. The description of the inclination angle θ3 of the first side surface 15b or the inclination angle θ4 of the second side surface 15c may be used for the inclination angle of the intermediate portion located on the +Z' side or the -Z' side with respect to the vibrating portion 611 (or the inner portion 613a). For example, on the +Y' plane, the inclination angle of the intermediate portion on the +Z' side may be the same as the inclination angle θ3, and may be, for example, about 54° (e.g., 52° or more and 56° or less). Also, for example, on the +Y' plane, the inclination angle of the intermediate portion on the -Z' side may be the same as the inclination angle θ4, and may be, for example, about 3° (e.g., 1° or more and 5° or less). On the -Y' plane, conversely to the above, the inclination angle of the intermediate portion on the -Z' side is the same as the inclination angle θ3, and the inclination angle of the intermediate portion on the +Z' side is the same as the inclination angle θ4.

[0184] The quartz crystal plate 603 may have a through hole penetrating the quartz crystal plate 603 in the thickness direction. The through hole, for example, contributes to electrical continuity between the front and back (upper and lower surfaces) of the quartz crystal plate 603 and / or contributes to reducing the likelihood that leakage vibration from the arrangement area of ​​the excitation electrode 607 propagates to the fixed part 613. The position, shape, and dimensions of the through hole may be appropriately set depending on the purpose, etc.

[0185] 11 illustrates a through hole 621h located between the inner portion 613a and the outer portion 613b. The through hole 621h is located, for example, partially or entirely (in the illustrated example, entirely) between the extraction electrodes 609 (more specifically, the pad portions 609a) arranged in the Z' direction. The length of the through hole 621h in the Z' direction is longer than the length in the X direction. In a plan view (in the X direction from another perspective), the through hole 621h may be contained in an intermediate portion between the inner portion 613a and the outer portion 613b (not illustrated), or may protrude toward the inner portion 613a side and / or the outer portion 613b side. In addition, when the through hole 621h is located between the inner portion 613a and the outer portion 613b, the through hole 621h may be located in the part of the inner portion 613a on the outer portion 613b side, or in the part of the outer portion 613b on the inner portion 613a side, or may be located across both. 21 For example, h contributes to reducing back-to-back conduction and propagation of leakage vibration.

[0186] In the illustrated example, no through-hole is provided between the vibration part 611 and the fixed part 613 (the inner part 613a). From another point of view, no through-hole is provided in the part consisting of the vibration part 611 and the inner part 613a (excluding the outer edge of the inner part 613a). This, for example, improves the strength of the above-mentioned part. However, instead of or in addition to the through-hole 621h, the through-hole 621h may be located between the vibration part 611 and the fixed part 613 (the inner part 613a). For example, this through-hole may contribute to the conduction between the front and back and the reduction of the propagation of the leakage vibration, similar to the through-hole 621h. In addition, although not particularly illustrated, a circular through-hole may be provided in the arrangement area of ​​the pad part 609a of the outer part 613b, or a through-hole of an appropriate shape may be provided between the two pad parts 609a of the outer part 613b.

[0187] (3. Conductive Pattern) Each of the conductor patterns 605 (605A and 605B) is the same as that of the first embodiment. 5Similarly to the first embodiment, the crystal element 601 has an extraction electrode 609 extending toward a portion of the fixed portion 613 located on the +X side with respect to the vibration portion 611. As a result, similarly to the first embodiment and as described with reference to FIG. 7, the pad portion 609a of the extraction electrode 609 on the +X side is bonded to the pad 111 by the bump 105, and the crystal element 601 is mounted in the package 103 in a cantilevered state.

[0188] Each of the conductor patterns 605 (605A and 605B) differs from each of the conductor patterns 605 in the first embodiment in that it further has an extraction electrode 609 extending toward a portion of the fixed portion 613 located on the -X side with respect to the vibration portion 611. This allows, for example, the crystal element 601 to be supported in a cantilevered manner with either the +X side or the -X side being the fixed end. Also, for example, the crystal element 601 can be supported at both ends by two pad portions 609a at both ends, or at both ends by four pad portions 609a at both ends, instead of being supported in a cantilevered manner.

[0189] Of course, as is clear from the fact that the description of the first embodiment may be applied to the second embodiment, each conductor pattern 605 may have only one extraction electrode 609. In this case, for example, both of the two conductor patterns 605 may have the extraction electrode 609 on only one of the +X side and the -X side, similar to the first embodiment. Also, unlike the first embodiment, one conductor pattern 605 may have the extraction electrode 609 on the +X side, while the other conductor pattern 605 may have the extraction electrode 609 on the -X side.

[0190] At least one extraction electrode 609 (pad portion 609a) of each conductor pattern 605 may be provided in a manner not shown in the drawings. For example, two pad portions 609a of one conductor pattern 605 may be provided in a portion of the fixed portion 613 located on one side of the vibrating portion 611 in the X direction and in a portion of the fixed portion 613 located on one side of the vibrating portion 611 in the Z' direction.

[0191] As described in the first embodiment, the pad portion 609a of each extraction electrode 609 may be provided on both the +Y' side and the -Y' side, or may be provided on only one side. In FIG. 11, the former is illustrated.

[0192] In each conductor pattern 605, the two extraction electrodes 609 extending to opposite sides in the X direction may extend to the same side in the Z' direction (as shown in the example), or may extend to opposite sides. In the former case, when mounting the crystal element 601 on the package 103 using the two pads 609a at both ends among the four pads 609a at the four corners, mounting is performed using two pads 609a located at a pair of diagonal corners. In this case, for example, the center of gravity of the crystal element 601 is likely to be located on the line connecting the two pads 609a, so that the crystal element 601 is stably supported.

[0193] The relationship (related to position, shape, size, etc.) between each part of the extraction electrode 609 (pad part 609a and wiring part 609b) and each part of the quartz crystal plate 603 (vibration part 611, fixed part 613, inner part 613a, and outer part 613b) is arbitrary. In the illustrated example, the wiring part 609b extends from the excitation electrode 607, exceeds the edge part 621a, and reaches the middle of the inner part 613a. The pad part 609a spreads from the middle of the inner part 613a to the outer part 613b. In this case, for example, the pad part 609a, which is fixed to the package 103 and affects vibration, is separated from the vibration part 611, but the conductive area can be secured by the pad part 609a at the step between the inner part 613a and the outer part 613b.

[0194] To repeat, the explanations relating to the relationship between each part of the extraction electrode 9 and each part of the quartz crystal plate 3 in the first embodiment may be used in the second embodiment, as long as no contradictions or the like arise. In this case, with respect to the example of FIG. 11, the vibration part 611 and the inner part 613a may be considered to correspond to the vibration part 11, and the outer part 613b may be considered to correspond to the fixed part 13. In addition, the explanations relating to the positional relationship between each part of the extraction electrode 209 and each part of the quartz crystal plate (reference numerals omitted) illustrated in FIG. 8 may also be used in the second embodiment, as long as no contradictions or the like arise. In this case, with respect to the example of FIG. 11, the vibration part 611 may be considered to correspond to the vibration part 11, and the fixed part 613 may be considered to correspond to the fixed part 13.

[0195] As an example of an embodiment different from the illustrated example, there is an embodiment in which the pad portion 609a extends beyond the edge portion 621a of the fixed portion 613 on the side of the vibrating portion 611 to the outer periphery side portion of the vibrating portion 611, as in the first embodiment. From another point of view, this embodiment is an embodiment in which the explanation of the first embodiment is simply applied to the second embodiment. Another embodiment is an embodiment in which the wiring portion 609b extending from the excitation electrode 607 extends beyond the inner portion 613a and reaches the outer portion 613b.

[0196] In the illustrated example, in a mode in which the edge of the pad portion 609a on the vibration portion 611 side is located on the inner portion 613a, the specific position of the edge is arbitrary. For example, the edge may be located at an intermediate position between the edge 621a and the edge 621b (or an edge on the inner portion 613a side of the intermediate portion (not illustrated) adjacent to the edge 621b), or may be located on the vibration portion 611 side or the outer portion 613b side with respect to the intermediate position.

[0197] As described in the first embodiment, the specific position, shape, size, and the like of the wiring portion 609b are arbitrary. In the illustrated example, the wiring portion 609b extends linearly from the excitation electrode 607 toward any of the four corners formed by the edge portion 621a (the vibration portion 611 from another point of view). After that, the wiring portion 609b extends parallel to the X direction from the corner to the pad portion 609a. Examples of aspects different from the illustrated example include an aspect in which the entire wiring portion 609b extends parallel to the X direction, an aspect in which the entire wiring portion 609b extends linearly while inclining in the X direction, and an aspect in which the bending position is located closer to the vibration portion 611 side or the inner portion 613a side than the corner.

[0198] (4. Recess) Except for their specific positions, the recesses 615A and 615B are similar to the recess 15. Therefore, to repeat, unless a contradiction occurs, the description of the recess 15 may be applied to the recesses 615A and 615B. Therefore, for example, the number of recesses 615A and recesses 615B overlapping one extraction electrode 609 is arbitrary.

[0199] In the illustrated example, a plurality of recesses 615B are provided, arranged along edge 621b, and overlap pad portion 609a. This configuration is similar to the configuration of recess 15 in the first embodiment. Therefore, for example, the explanation of the number and positions of recesses 15 in the first embodiment, and the positional relationship between recess 15 and extraction electrode 9 may be applied to recess 615B, with vibrating portion 611 and inner portion 613a corresponding to vibrating portion 611 in the first embodiment, and outer portion 613b corresponding to fixed portion 13 in the first embodiment.

[0200] In the following description, for convenience, the recess 615A will be described taking the +Y' side surface as an example, although the -Y' side surface is similar.

[0201] In the illustrated example, as described above, the recess 615A is located at a corner portion defined by the edge portion 621a. More specifically, the edge portion 621a is located on the +X side, the -X side, the +Z' side, and the -Z side with respect to the vibration portion 611. ’The substrate 621 has four partial edges 621aa positioned on each side of the substrate 621, and has four corners. A recess 615A is provided at each of the four corners. In other words, the recess 615A is provided at a corner formed by two partial edges 621aa that intersect with each other.

[0202] When it is said that the recess 615A is located at a corner (or that the corner of the edge 621a is cut out), unless otherwise specified, the recess 615A may cut out only one of the two partial edges 621aa constituting the corner, or may cut out both. In the illustrated example, the recess 615A cuts out the partial edge 621aa located on the +X side or the -X side with respect to the vibrating part 611, and does not cut out the partial edge 621aa located on the +Z' side or the -Z' side with respect to the vibrating part 611. In a mode in which the recess 615A cuts out only one of the two partial edges 612aa, the partial edge 621aa on the +Z' side or the -Z' side may be cut out, unlike the illustrated example.

[0203] In addition, when the recess 615A is located at a corner (or the corner of the edge 621a is cut out), unless otherwise specified, the recess 615A may overlap the intersection of the two partial edges 621aa constituting the corner (a virtual point obtained by extending the two partial edges 621aa when the recess 615A cuts out), or may be separated from the intersection by a relatively short distance. It is natural that the recess 615A and the intersection may be separated by a distance of about the manufacturing error. The short distance may be, for example, 1 / 2 or less, 1 / 3 or less, or 1 / 5 or less of the width w1 (see FIG. 3) of the recess 615A, regardless of whether it is a manufacturing error or not, and may be, for example, 10 μm or less, 5 μm or less, or 1 μm or less.

[0204] It should be noted that when a corner (or angular portion) is cut out by the recess 615A, it can be thought of or expressed as not having a corner. However, for the sake of convenience, this disclosure does not use such a thought or expression. Even if a corner is cut out by the recess 615A, it can be easily understood that a angular portion (corner portion) would have been formed by extending the partial edge portion 621aa extending in mutually intersecting directions if the recess 615A had not been provided.

[0205] The shape and dimensions of the recess 615A are arbitrary, regardless of which of the two partial edges 621aa constituting the corner is cut out. For example, the planar shape of the recess 615A may be rectangular, triangular, or semicircular, as described in the first embodiment. For example, in an aspect in which the recess 615A cuts out only one partial edge 621aa, the description of the first embodiment may be directly applied to the shape and dimensions of the recess 615A in plan view. For example, in an aspect in which the recess 615A cuts out two partial edges 621aa, the shape of the recess 615A in plan view may be a shape that has a depth in a direction along a straight line (for example, a diagonal line) that bisects the angle formed by the two partial edges 621aa, or a shape that has a depth in a direction perpendicular to one partial edge 621aa and extends beyond the other edge 621a. The directions for measuring the width w1 and the depth d1 described in the first embodiment may be reasonably determined from the shape of the recess 615A. When the recess 615A has two partial edges 621aa cut out and the value of the depth d1 differs depending on which partial edge 621aa is used as the reference, the depth d1 may be determined to be maximum, as in the first embodiment.

[0206] As in the illustrated example, in the aspect in which the recess 615A cuts out only the partial edge 621aa located on the +X side or the -X side with respect to the vibration part 611, the direction of cutting out the edge is the same as that of the recess 15 in the first embodiment. Therefore, the description of the inclination angle in the case where the side surface of the recess 15 is formed by a crystal plane can be directly applied to the inclination angle in the case where the side surface of the recess 615A is formed by a crystal plane. Unlike the illustrated example, in the aspect in which the recess 615A cuts out only the partial edge 621aa located on the +Z' side or the -Z' side with respect to the vibration part 611, the description of the inclination angle in the first embodiment may be appropriately applied in consideration of the relationship between each side surface and the orthogonal coordinate system XY'Z'. For example, the description of the inclination angle θ2 of the third side surface 15d may be applied to the inclination angle of the side surface on the +X side or the -X side. The description of the inclination angle θ3 of the first side surface 15b may be applied to the inclination angle of the side surface on the +Z' side. Regarding the inclination angle of the side surface on the -Z' side, the description of the inclination angle θ4 of the second side surface 15c may be cited.

[0207] In the illustrated example, the recess 615A cuts out only one of the two partial edges 621aa (more specifically, the partial edge 621aa located on the +X side or the -X side with respect to the vibrating part 611). The upper surface edge of the recess 615A (the edge at the height of the first region 622A) is connected to the partial edge 621aa that is not cut out in a substantially straight line. From another perspective, the side surface of the recess 615A on the +Z' side or the -Z' side is connected to the side surface of the inner part 613a on the vibrating part 611 side of the part located on the +Z' side with respect to the vibrating part 611 (from another perspective, the inclined surface of the middle part not shown) or the side surface of the inner part 613a on the vibrating part 611 side of the part located on the -Z' side with respect to the vibrating part 611 (from another perspective, the inclined surface of the middle part not shown) so as to form a substantially same plane. This is a difference in shape from the recess 15 that is not located at a corner. Unlike the illustrated example, the upper edge of the recess 615A and the partial edge 621aa may not be connected in a straight line, but may be connected to each other by intersecting to form a corner, and / or at least one of them may be curved at the position where they connect to each other.

[0208] As described above, the recesses 615A are provided at the four corners of a rectangle. In other words, the four recesses 615A are provided line-symmetrically with respect to a center line (not shown) of the vibration part 611 (or the excitation electrode 607) parallel to the X direction. The four recesses 615A are also provided line-symmetrically with respect to a center line of the vibration part 611 (or the excitation electrode 607) parallel to the Z' direction. As described in the first embodiment, the shapes and dimensions of the multiple recesses 615A may be the same as each other or may be different from each other.

[0209] In the illustrated example, two of the four recesses 615A overlap the extraction electrode 609. As described in the first embodiment, the recesses 615A may be provided only at positions overlapping the extraction electrode 609. Therefore, for example, on the surface on the +Y' side, the two recesses 615A on the +Z' side may not be provided, and only the two recesses 615A on the -Z' side may be provided. Also, for example, unlike the illustrated example, in an aspect in which the first conductor pattern 605A has only one extraction electrode 609, only one recess 615A may be provided. As is clear from the description of the conductor pattern 605, the recess 615A overlaps the wiring portion 609b of the extraction electrode 609. To repeat, for example, the description of the wiring portion 209b and the recess 215 described with reference to FIG. 10 may be applied to the wiring portion 609b and the recess 615A as long as no contradiction or the like occurs.

[0210] When the description related to the depth of the recess 15 according to the first embodiment is applied to the recess 615A, the term "third surface 21A" may be replaced with the term "first region 622A" unless a contradiction occurs. When the description related to the depth of the recess 15 according to the first embodiment is applied to the recess 615B, the term "third surface 21A" may be replaced with the term "second region 622B" and the term "first surface 19A" may be replaced with the term "first surface 619A" and / or the term "first region 622A" unless a contradiction occurs. Furthermore, the term for the thickness of the vibration section 11 may not be replaced and / or may be replaced with the term "inner portion 613a" unless a contradiction occurs.

[0211] In the description of the first embodiment, 16 μm or less or 12 μm or less was exemplified as a specific example of the height h1 from the first surface 19A to the third surface 21A. As described above, this range may be applied to the height from the first surface 619A to the first region 622A, the height from the first region 622A to the second region 622B, and / or the height from the first surface 619A to the second region 622B in the second embodiment. However, as described above, in the second embodiment, it is easier to reduce the size of one step compared to the first embodiment. Therefore, in the second embodiment, the size (height h1) of one step exemplified in the description of the first embodiment can be further reduced. For example, the height from the first surface 619A to the first region 622A and / or the height from the first region 622A to the second region 622B may be half the above, 8 μm or less or 6 μm or less.

[0212] (5. Manufacturing method of quartz crystal element) The manufacturing method of the quartz crystal element 601 may be, for example, generally similar to the manufacturing method of the quartz crystal element 1 according to the first embodiment. The gradual change in thickness of the fixing portion 613 may be realized, for example, by adding a process of forming an etching mask on the quartz crystal plate 603 and etching it.

[0213] Specifically, for example, first, as in the first embodiment, etching is performed through an etching mask having a shape similar to the planar shape of quartz crystal plate 603. Next, etching is performed through an etching mask having a shape similar to the planar shape of fixed portion 613. Next, etching is performed through an etching mask having a shape similar to the planar shape of outer portion 613b. In this manner, vibrating portion 611, inner portion 613a thicker than vibrating portion 611, and outer portion 613b thicker than inner portion 613a are formed.

[0214] (6. Summary of quartz crystal elements) As described above, in the second embodiment, the crystal element 601 also has a piezoelectric plate (crystal plate 603), a first excitation electrode (for example, excitation electrode 607 of the first conductor pattern 605A), and a first extraction electrode (for example, extraction electrode 609 of the first conductor pattern 605A). The crystal plate 603 has a vibrating part 611 and a fixed part 613 which constitute different regions from each other in a plan view. The vibrating part 611 has a first surface 619A facing the first side (+Y' side) and a second surface 619B facing the second side (-Y' side) opposite to the first side. The fixed part 613 has a third surface 621A facing the +Y' side and a fourth surface 621B facing the -Y' side. The third surface 621A is higher on the +Y' side than the first surface 619A. The excitation electrode 607 overlaps the first surface 619A. The extraction electrode 609 is extracted from the excitation electrode 607 and overlaps the third surface 621A. The quartz crystal plate 603 has a first recess (a recess 615A on the +Y' side) recessed from the third surface 621A to the -Y' side. The recess 615A cuts out a first edge portion (edge ​​portion 621a) on the first surface 619A side of the third surface 621A in a plan view. The extraction electrode 609 has a portion that extends from the first surface 619A to the third surface 621A via the recess 615A.

[0215] Therefore, for example, the same effect as in the first embodiment is achieved. Specifically, for example, the recess 615A can improve the reliability of the conduction of the extraction electrode 609. In addition, for example, while ensuring the strength of the fixed portion 613 as a whole, the rigidity is reduced in a part on the vibrating portion 611 side, and the strain applied to the fixed portion 613 from the bump 105 (FIG. 7) is absorbed by the recess 615A, so that the probability of the vibration characteristics being deteriorated can be reduced. In addition, for example, the probability that waves arriving at various positions on the edge of the fixed portion 613 from the vibrating portion 611 are reflected in the same direction with the same phase can be reduced, so that the probability of the reflected waves appearing as noise can be reduced.

[0216] In the second embodiment, the first edge (edge ​​621a) has a first partial edge (e.g., partial edge 621aa on the +X side) and a second partial edge (e.g., partial edge 621aa on the -Z' side). The first partial edge is located on one side (+X side) of the first direction (e.g., X direction) with respect to the vibrating section 611 in a plan view. The second partial edge is located on one side (e.g., -Z' side) of the second direction (e.g., Z' direction) perpendicular to the first direction with respect to the vibrating section 611 in a plan view, and forms a corner with the first partial edge. The first recess (recess 615A) cuts out at least one of the first partial edge and the second partial edge at the corner.

[0217] In this case, as described in the description of the outline of the second embodiment (Chapter 2, Section 1), for example, since the extraction electrode 609 extends from the excitation electrode 607 toward the corner, the influence of the extraction electrode 609 on vibration is reduced, although it depends on the vibration mode used, etc. Also, by connecting the side surface of the recess 615A and the side surface of the inner portion 613a that are along the same direction (X direction in the illustrated example), the side surface of the recess 615A can be substantially extended. As a result, the conductive area of ​​the extraction electrode 609 passing through the side surface of the recess 615A can be secured, and the reliability of the conduction can be improved.

[0218] The third surface 621A may have a first region 622A and a second region 622B. The first region 622A has the first edge portion (edge ​​portion 621a). The second region 622B is located on the opposite side of the first surface 619A with respect to the first region 622A in a plan view, and is higher on the first side (+Y' side) than the first region 622A. The first extraction electrode (for example, the extraction electrode 609 on the +X side of the first conductor pattern 605A) may reach the second region 622B via the first region 622A.

[0219] In this case, for example, as described in the description of the outline of the second embodiment, the height from the first surface 619A to the first region 622A can be reduced while ensuring the thickness (in other words, strength) of the outer portion 613b, thereby reducing the likelihood of disconnection at the edge portion 621a. Also, for example, compared to a mode in which the outer portion 613b is connected to the vibrating portion 611 without the inner portion 613a, the effect of the fixed portion 613 restricting the vibration of the vibrating portion 611 is reduced, improving the vibration characteristics.

[0220] The piezoelectric blank (crystal blank 603) may have a second region recess (recess 615B) recessed from the second region 622B to the second side (e.g., the -Y' side). The recess 615B may be formed by cutting out the second region edge (edge ​​621b) on the first region 622A side of the second region 622B in a plan view. The first extraction electrode (e.g., extraction electrode 609 on the +X side of the first conductor pattern 605A) may extend from the first recess (recess 615A) to the second region 622B via the recess 615B.

[0221] In this case, for example, not only is the probability of disconnection at edge 621a reduced by recess 615A, but the probability of disconnection at edge 621b is reduced by recess 615B, resulting in improved reliability of conduction throughout extraction electrode 609.

[0222] The first extraction electrode (for example, the extraction electrode 609 on the +X side of the first conductor pattern 605A) may have a wiring portion 609b and a pad portion 609a. The wiring portion 609b may extend from the first excitation electrode (the excitation electrode 607 of the first conductor pattern 605A) and pass through the first recess (the recess 615A). The pad portion 609a may have a portion overlapping the second region 622B and may be wider than the wiring portion 609b in the direction along the first edge portion (the edge portion 621a).

[0223] In this case, for example, pad portion 609a, which is fixed to package 103 and affects vibration, is separated from vibration portion 611. When wiring portion 609b passes through recess 615A, the conduction area is smaller than when pad portion 609a overlaps recess 615A, but as described above, the height from first surface 619A to first region 622A is lowered, reducing the likelihood of disconnection. Therefore, overall, it is possible to improve the vibration characteristics while improving the reliability of conduction.

[0224] The first region 622A may surround the vibration part 611 in a plan view. The second region 622B may be located on one side or both sides in a first direction (e.g., X direction) with respect to the vibration part 611 and the first region 622A in a plan view, and may not be located on either side in a second direction (e.g., Z' direction).

[0225] In this case, for example, compared to a mode in which the vibrating part 611 is surrounded by the second region 622B (this mode is also included in the technology according to the present disclosure), the effect of the second region 622B, which has a relatively high strength, on the vibration of the vibrating part 611 is reduced. On the other hand, compared to a mode in which the vibrating part 611 is not surrounded by the first region 622A (this mode is also included in the technology according to the present disclosure), it is possible to reduce the probability that the vibrating part 611 will be deformed by impact or the like. Therefore, overall, it is possible to improve the vibration characteristics while improving the strength.

[0226] The piezoelectric plate (quartz crystal plate 603) may have a through-hole 621h that penetrates the quartz crystal plate 603 in the thickness direction between the first region 622A and the second region 622B.

[0227] In this case, for example, as described above, the conduction between the front and back is facilitated and / or the propagation of leakage vibration is reduced. Also, compared to the mode in which a through hole is formed between the vibrating part 611 and the first region 622A (the inner part 613a), it is easier to improve the strength of the portion (relatively thin portion) consisting of the vibrating part 611 and the inner part 613a.

[0228] The crystal element 601 may further include a second excitation electrode (for example, the excitation electrode 607 on the -Y' side), a second extraction electrode (for example, the extraction electrode 609 on the +X side of the second conductor pattern 605B), a third extraction electrode (for example, the extraction electrode 609 on the -X side of the first conductor pattern 605A), and a fourth extraction electrode (for example, the extraction electrode 609 on the -X side of the second conductor pattern 605B). The second excitation electrode may overlap the second surface 619B. The second extraction electrode may be extracted from the second excitation electrode and overlap the fourth surface 621B. The third extraction electrode may be extracted from the first excitation electrode (for example, the excitation electrode 607 on the +Y' side) in a direction different from the first extraction electrode (the extraction electrode 609 on the +X side of the first conductor pattern 605A) and overlap the third surface 621A. The fourth extraction electrode may be extracted from the second excitation electrode in a direction different from the second extraction electrode and overlap the fourth surface 621B. The fixed portion 613 may surround the vibration portion 611 in a plan view. The first extraction electrode may have a portion located on the side of the first partial edge (for example, the partial edge 621aa on the +X side) and the side of the second partial edge (for example, the partial edge 621aa on the -Z' side) with respect to the first excitation electrode. The second extraction electrode may have a portion located on the side of the first partial edge (+X side) and the opposite side (+Z' side) to the second partial edge with respect to the second excitation electrode. The third extraction electrode may have a portion located on the opposite side (-X side) to the side of the first partial edge and the side of the second partial edge (-Z' side) with respect to the first excitation electrode. The fourth extraction electrode may have a portion located on the opposite side (−X side) from the first portion edge portion and on the opposite side (+Z′ side) from the second portion edge portion with respect to the second excitation electrode.

[0229] In this case, for example, as described above, various mounting modes are possible. In addition, since the arrangement of the conductor pattern 605 is symmetrical with respect to the center line parallel to the X direction and the center line parallel to the Z' direction, the electrical and / or mass influence of the conductor pattern 605 on the vibration of the quartz crystal plate 603 tends to be symmetrical. As a result, the probability of unintended peculiar vibration occurring is reduced. In turn, the characteristics of the quartz crystal element 601 are improved.

[0230] The first edge (edge ​​621a) may have a third partial edge (e.g., partial edge 621aa on the -X side) and a fourth partial edge (e.g., partial edge 621aa on the +Z' side). The third partial edge may face the first partial edge (e.g., partial edge 621aa on the +X side) across the vibration part 611. The fourth partial edge may face the second partial edge (e.g., partial edge 621aa on the -Z' side) across the vibration part 611. The piezoelectric blank (crystal blank 603) may have a total of four recesses 615A including a first recess that is recessed from the third surface 621A to the second side (-Y' side) and cuts out the edge 621a at four corners formed by the first partial edge, the second partial edge, the third partial edge, and the fourth partial edge in a plan view.

[0231] In this case, the recess 615A is arranged line-symmetrically with respect to a center line parallel to the X direction and line-symmetrically with respect to a center line parallel to the Z' direction with respect to the vibrating part 611 as a reference. As a result, the effect of the recess 615A on the vibration of the vibrating part 611 tends to be symmetric. As a result, the probability of unintended peculiar vibration occurring is reduced. In turn, the characteristics of the crystal element 601 are improved.

[0232] In the above second embodiment, the crystal element 601 is an example of a piezoelectric vibration element. The crystal blank 603 is an example of a piezoelectric blank. The +Y' side is an example of a first side. The -Y' side is an example of a second side. The excitation electrode 7 of the first conductor pattern 605A is an example of a first excitation electrode. The excitation electrode 7 of the second conductor pattern 605B is an example of a second excitation electrode. The extraction electrode 9 on the +X side of the first conductor pattern 605A is an example of a first extraction electrode. The extraction electrode on the +X side of the second conductor pattern 605B is an example of a second extraction electrode. The extraction electrode 9 on the -X side of the first conductor pattern 605A is an example of a third extraction electrode. The extraction electrode on the -X side of the second conductor pattern 605B is an example of a fourth extraction electrode. The edge 621a on the +Y' side is an example of a first edge. The edge 621a on the -Y' side is an example of a second edge. The recess 615A on the +Y' side is an example of a first recess. The recess 615A on the -Y' side is an example of a second recess. The partial edge 621aa on the +X side is an example of a first partial edge. The partial edge 621aa on the -Z' side is an example of a second partial edge. The partial edge 621aa on the -X side is an example of a third partial edge. The partial edge 621aa on the +Z' side is an example of a fourth partial edge. The edge 621b is an example of a second region edge. The recess 615B is an example of a second region recess.

[0233] The technology according to the present disclosure is not limited to the above-described embodiments, and may be implemented in various forms.

[0234] The above-mentioned embodiments and various examples may be appropriately combined. For example, the configuration shown in FIG. 10 in which the fixing portion is higher only on one side in the thickness direction relative to the vibration portion may be applied to the configuration shown in FIG. 9A and FIG. 9B in which the fixing portion extends over two or more sides. The through-hole shown in the second embodiment may be applied to the first embodiment. The recessed portion shown in the second embodiment in which the extraction electrodes do not overlap may be applied to the first embodiment. Also, as described in the second embodiment, the piezoelectric base plate does not need to have an intermediate portion whose thickness changes between the fixing portion and the vibration portion, and this is also the case in the first embodiment.

[0235] The piezoelectric body is not limited to quartz. For example, the piezoelectric body may be other single crystals or may be made of polycrystals (e.g., ceramics). The piezoelectric body is not limited to one that uses the fundamental vibration of thickness shear vibration, but may use other vibration modes or may use overtone vibration. Furthermore, the piezoelectric body may use elastic waves excited by an excitation electrode formed only on the first surface (or second surface). The cut of the quartz blank that uses thickness shear vibration is not limited to the AT cut. For example, it may be the BT cut. The quartz blank is not limited to one made of quartz only, but may also be one made of a material in which a dopant made of metal or the like is injected into quartz.

[0236] The piezoelectric vibration element may be mounted by a means other than two conductive bumps. For example, a pad portion located on the lower surface of a fixed portion of one extraction electrode may be bonded to a pad of the package by one conductive bump, and a pad portion located on the upper surface of the fixed portion of one extraction electrode may be connected to a pad of the package by one bonding wire. Alternatively, a lower surface of the fixed portion may be bonded to the package by an insulating adhesive, and pad portions located on the upper surfaces of the fixed portions of two extraction electrodes may be connected to two pads of the package by two bonding wires.

[0237] From the present disclosure, it is possible to extract a piezoelectric vibration element that does not require the first recess (recess 615A) to be located at a corner of the vibration part. The piezoelectric vibration element may be characterized, for example, in that the thickness of the fixing part changes stepwise, or in that two extraction electrodes are provided for one excitation electrode.

[0238] Furthermore, from the present disclosure, it is possible to extract a piezoelectric vibration element that does not require that, when the size of the first recess (e.g., recess 15 on the +Y' side) in the direction along the first edge portion (21a) is referred to as the width, the side surface (e.g., first side surface 15b) has an inclined surface that inclines from the bottom of the first recess to the third surface (21A) in a direction in which the width of the first recess increases toward the first side (+Y' side), and the extraction electrode (9) has a portion that reaches from the bottom of the first recess to the third surface via the inclined surface. The piezoelectric vibration element may be characterized, for example, in that the width and / or depth of the recess is larger than a predetermined portion, that the bottom surface (15a) of the recess extends further into the third surface than the edge portion (21a) of the third surface, that the wiring portion (9b) of the extraction electrode overlaps at least a portion of the recess, or that the side surface of the recess has a crystal surface.

[0239] The following concepts can be extracted from this disclosure.

[0240] (Concept 1) A piezoelectric plate having a vibration portion and a fixed portion which define different regions in a plan view, the vibration portion having a first surface facing a first side and a second surface facing a second side opposite to the first side, the fixed portion having a third surface facing the first side and a fourth surface facing the second side, the third surface being higher on the first side than the first surface; a first excitation electrode overlying the first surface; a first extraction electrode that is extracted from the first excitation electrode and overlaps the third surface; It has the piezoelectric plate has a first recess recessed from the third surface toward the second side, the first recess is formed by cutting out a first edge portion of the third surface on the first surface side in a plan view, the first extraction electrode has a portion extending from the first surface through the first recess to the third surface, The first edge portion is a first partial edge portion located on one side in a first direction with respect to the vibration portion in a plan view; a second portion edge portion that is located on one side of the vibration portion in a second direction perpendicular to the first direction in a plan view and that forms a corner with the first portion edge portion, The first recess is formed by cutting out at least one of the first portion edge portion and the second portion edge portion at the corner portion. Piezoelectric vibration element.

[0241] (Concept 2) The third surface is a first region having the first edge; a second region located on an opposite side of the first surface with respect to the first region in a plan view and higher toward the first surface than the first region; The first extraction electrode reaches the second region via the first region. 2. The piezoelectric vibration element of claim 1.

[0242] (Concept 3) the piezoelectric plate has a second region recess recessed from the second region to the second side, the second region recess is formed by cutting out an edge of the second region on the first region side in a plan view, The first extraction electrode extends from the first recess to the second region via the second region recess. 3. The piezoelectric vibration element of claim 2.

[0243] (Concept 4) The first extraction electrode is a wiring portion extending from the first excitation electrode and passing through the first recess; a pad portion having a portion overlapping the second region and extending wider than the wiring portion in a direction along the first edge portion; A piezoelectric vibration element according to concept 2 or 3.

[0244] (Concept 5) the first region surrounds the vibration portion in a plan view, The second region is located on one side or both sides in the first direction with respect to the vibration section and the first region in a plan view, and is not located on either side in the second direction. The piezoelectric vibration element according to any one of Concepts 2 to 4.

[0245] (Concept 6) The piezoelectric plate has a through hole penetrating the piezoelectric plate in a thickness direction between the first region and the second region. The piezoelectric vibration element according to any one of Concepts 2 to 5.

[0246] (Concept 7) a second excitation electrode overlying the second surface; a second extraction electrode that is extracted from the second excitation electrode and overlaps the fourth surface; a third extraction electrode that is extracted from the first excitation electrode in a direction different from that of the first extraction electrode and overlaps the third surface; a fourth extraction electrode that is extracted from the second excitation electrode in a direction different from that of the second extraction electrode and overlaps with the fourth surface; and the fixed portion surrounds the vibration portion in a plan view, the first extraction electrode has a portion located on a side of the first portion edge portion and a side of the second portion edge portion with respect to the first excitation electrode, the second extraction electrode has a portion located on a side of the first portion edge portion and on an opposite side to the second portion edge portion with respect to the second excitation electrode, the third extraction electrode has a portion located on a side opposite to the first portion edge portion side and on a side of the second portion edge portion side with respect to the first excitation electrode, The fourth extraction electrode has a portion located on the opposite side to the first portion edge portion and the opposite side to the second portion edge portion with respect to the second excitation electrode. The piezoelectric vibration element according to any one of Concepts 1 to 6.

[0247] (Concept 8) The first edge portion is a third portion edge portion facing the first portion edge portion across the vibration portion; a fourth portion edge portion facing the second portion edge portion with the vibration portion interposed therebetween, The piezoelectric plate has a total of four recesses, including the first recess, recessed from the third surface toward the second side and cutting out the first edge, at four corners defined by the first portion edge portion, the second portion edge portion, the third portion edge portion, and the fourth portion edge portion in a plan view. The piezoelectric vibration element according to any one of Concepts 1 to 7.

[0248] (Concept 9) When a size of the first recess in a direction along the first edge portion is referred to as a width, a side surface of the first recess that intersects with the first edge portion in a plan view has an inclined surface that is inclined from a bottom of the first recess to the third surface in a direction in which the width of the first recess becomes larger toward the first side, The first extraction electrode has a portion that extends from a bottom of the first recess, via the inclined surface, to the third surface. The piezoelectric vibration element according to any one of Concepts 1 to 8.

[0249] (Concept 10) A piezoelectric plate having a vibration portion and a fixed portion which define different regions in a plan view, the vibration portion having a first surface facing a first side and a second surface facing a second side opposite to the first side, the fixed portion having a third surface facing the first side and a fourth surface facing the second side, the third surface being higher on the first side than the first surface; a first excitation electrode overlying the first surface; a first extraction electrode that is extracted from the first excitation electrode and overlaps the third surface; It has the piezoelectric plate has a first recess recessed from the third surface toward the second side, the first recess is formed by cutting out a first edge portion of the third surface on the first surface side in a plan view, the first extraction electrode has a portion extending from the first surface through the first recess to the third surface, When a size of the first recess in a direction along the first edge portion is referred to as a width, a side surface of the first recess that intersects with the first edge portion in a plan view has an inclined surface that is inclined from a bottom of the first recess to the third surface in a direction in which the width of the first recess becomes larger toward the first side, The first extraction electrode has a portion that extends from a bottom of the first recess, via the inclined surface, to the third surface. Piezoelectric vibration element.

[0250] (Concept 11) The side surface of the first recess has a crystal surface. 11. The piezoelectric vibration element of concept 9 or 10.

[0251] (Concept 12) When the size of the first recess in a direction along the first edge portion is referred to as a width, the width of the first recess at the height of the first edge portion is greater than the thickness of the vibration portion. 12. The piezoelectric vibration element according to any one of Concepts 1 to 11.

[0252] (Concept 13) a depth of the first recess from the first edge portion in a plan view, the depth at a height of the first edge portion being greater than a thickness of the vibration portion; 13. The piezoelectric vibration element according to any one of Concepts 1 to 12.

[0253] (Concept 14) When the size of the first recess in a direction along the first edge portion is referred to as a width, the width of the first recess at the height of the first edge portion is greater than the height from the first surface to the first edge portion. 14. The piezoelectric vibration element according to any one of Concepts 1 to 13.

[0254] (Concept 15) a depth of the first recess from the first edge portion in a plan view, the depth at a height of the first edge portion being greater than a height from the first surface to the first edge portion; 15. The piezoelectric vibration element according to any one of Concepts 1 to 14.

[0255] (Concept 16) The inner surface of the first recess is a bottom surface that is connected to the first surface and is flush with the first surface; an end surface located on the opposite side of the bottom surface from the first surface in a plan view, the end surface rising from the bottom surface to the first edge portion while inclining in a direction approaching the height of the first edge portion as it moves away from the bottom surface in a plan view; In a plan view, the bottom surface is recessed toward the third surface side relative to the first edge portion. 16. The piezoelectric vibration element according to any one of Concepts 1 to 15.

[0256] (Concept 17) the piezoelectric plate has a fifth surface that connects the first surface and the first edge portion and is inclined so as to be positioned closer to the first edge portion, When the size of the first recess in a direction along the first edge portion is referred to as a width, the width of the first recess at the height of the first edge portion is greater than the length of the fifth surface from the first surface to the first edge portion in a plan view. 17. The piezoelectric vibration element according to any one of Concepts 1 to 16.

[0257] (Concept 18) the piezoelectric plate has a fifth surface that connects the first surface and the first edge portion and is inclined so as to be positioned closer to the first edge portion, a depth of the first recess from the first edge portion in a plan view, the depth being at a height of the first edge portion, which is greater than a length of the fifth surface from the first surface to the first edge portion in a plan view; 18. The piezoelectric vibration element according to any one of Concepts 1 to 17.

[0258] (Concept 19) The first extraction electrode is a wiring portion extending from the first excitation electrode; a pad portion connected to the wiring portion and extending wider than the wiring portion in a direction along the first edge portion, The first recess has a portion that overlaps with the wiring portion in a plan view. 19. The piezoelectric vibration element according to any one of Concepts 1 to 18.

[0259] (Concept 20) A piezoelectric vibration element according to any one of concepts 1 to 19, a package in which the piezoelectric vibration element is mounted; A piezoelectric device having a [Explanation of symbols]

[0260] 1,601...quartz crystal element (piezoelectric vibration element), 3,603...quartz crystal plate (piezoelectric plate), 7,607...excitation electrode (first excitation electrode), 9,609...extraction electrode (first extraction electrode), 11,611...vibration portion, 13,613...fixing portion, 15,615A...recess (first recess), 15b...first side (side), 19A,619A...first surface, 19B,619B...second surface, 21A,621A...second 3 sides , 21B, 621B...No. 4 sides , 21a, 621a...edge portion (first edge portion), 621aa...partial edge portion (first partial edge portion to fourth partial edge portion), 101...quartz crystal device (piezoelectric device).

Claims

1. A piezoelectric base plate having a vibrating portion and a fixed portion which define different regions in a plan view, the vibrating portion having a first surface facing a first side and a second surface facing a second side opposite to the first side, the fixed portion having a third surface facing the first side and a fourth surface facing the second side, the third surface being higher toward the first side than the first surface, and the fourth surface being higher toward the second side than the second surface; a first excitation electrode overlying the first surface; a first extraction electrode that is extracted from the first excitation electrode and overlaps the third surface; It has the piezoelectric plate has a first recess recessed from the third surface toward the second side, the first recess is formed by cutting out a first edge portion of the third surface on a side of the first surface in a plan view, the first extraction electrode has a portion extending from the first surface to the third surface via the first recess, The first edge portion is a first partial edge portion located on one side in a first direction with respect to the vibration portion in a plan view; a second portion edge portion that is located on one side of the vibration portion in a second direction perpendicular to the first direction in a plan view and that forms a corner with the first portion edge portion, The first recess is formed by cutting out at least one of the first portion edge and the second portion edge at the corner. Piezoelectric vibration element.

2. the first partial edge portion has a first main portion that extends over an entire length of all of the excitation electrodes including the first excitation electrode when viewed in the first direction, without being recessed from the third surface to the second side, and without being cut out in a plan view, the second partial edge portion has a second main portion that extends over an entire length of all of the excitation electrodes as viewed in the second direction, without being recessed from the third surface to the second side, and without being cut out in a plan view, The first recess is a notch in at least one of the first main portion and the second main portion in a plan view. The piezoelectric vibrator according to claim 1 .

3. The piezoelectric blank is an AT-cut quartz crystal piece, the first side is the +Y' side, and the first recess is located at the corner formed by the first partial edge portion located on the +X side with respect to the vibrating portion and the second partial edge portion located on the -Z' side with respect to the vibrating portion; or The first side is the −Y′ side, and the first recess is located at the corner formed by the first portion edge portion located on the +X side with respect to the vibration portion and the second portion edge portion located on the +Z′ side with respect to the vibration portion. The piezoelectric vibrator according to claim 1 .

4. A piezoelectric base plate having a vibration portion and a fixed portion which define different regions from each other in a plan view, the vibration portion having a first surface facing a first side and a second surface facing a second side opposite to the first side, the fixed portion having a third surface facing the first side and a fourth surface facing the second side, the third surface being higher on the first side than the first surface; a first excitation electrode overlying the first surface; a first extraction electrode that is extracted from the first excitation electrode and overlaps the third surface; It has the piezoelectric plate has a first recess recessed from the third surface toward the second side, the first recess is formed by cutting out a first edge portion of the third surface on a side of the first surface in a plan view, the first extraction electrode has a portion extending from the first surface to the third surface via the first recess, The first edge portion is a first partial edge portion located on one side in a first direction with respect to the vibration portion in a plan view; a second portion edge portion that is located on one side of the vibration portion in a second direction perpendicular to the first direction in a plan view and that forms a corner with the first portion edge portion, The first recess is formed by cutting out at least one of the first portion edge portion and the second portion edge portion at the corner portion, The third surface is a first region having the first edge; a second region located on an opposite side of the first surface with respect to the first region in a plan view and higher toward the first surface than the first region; the first extraction electrode reaches the second region via the first region, the piezoelectric plate has a second region recess recessed from the second region to the second side, the second region recess is formed by cutting out an edge of the second region on a side of the first region in a plan view, The first extraction electrode extends from the first recess to the second region via the second region recess. Piezoelectric vibration element.

5. The first extraction electrode is a wiring portion extending from the first excitation electrode and passing through the first recess; a pad portion having a portion overlapping the second region and extending wider than the wiring portion in a direction along the first edge portion; The piezoelectric vibration element according to claim 4 .

6. A piezoelectric base plate having a vibration portion and a fixed portion which define different regions from each other in a plan view, the vibration portion having a first surface facing a first side and a second surface facing a second side opposite to the first side, the fixed portion having a third surface facing the first side and a fourth surface facing the second side, the third surface being higher on the first side than the first surface; a first excitation electrode overlying the first surface; a first extraction electrode that is extracted from the first excitation electrode and overlaps the third surface; It has the piezoelectric plate has a first recess recessed from the third surface toward the second side, the first recess is formed by cutting out a first edge portion of the third surface on a side of the first surface in a plan view, the first extraction electrode has a portion extending from the first surface to the third surface via the first recess, The first edge portion is a first partial edge portion located on one side in a first direction with respect to the vibration portion in a plan view; a second portion edge portion that is located on one side of the vibration portion in a second direction perpendicular to the first direction in a plan view and that forms a corner with the first portion edge portion, The first recess is formed by cutting out at least one of the first portion edge portion and the second portion edge portion at the corner portion, The third surface is a first region having the first edge; a second region located on an opposite side of the first surface with respect to the first region in a plan view and higher toward the first surface than the first region; the first extraction electrode reaches the second region via the first region, the first region surrounds the vibration portion in a plan view, The second region is located on one side or both sides in the first direction with respect to the vibration portion and the first region in a plan view, and is not located on either side in the second direction. Piezoelectric vibration element.

7. A piezoelectric base plate having a vibration portion and a fixed portion which define different regions from each other in a plan view, the vibration portion having a first surface facing a first side and a second surface facing a second side opposite to the first side, the fixed portion having a third surface facing the first side and a fourth surface facing the second side, the third surface being higher on the first side than the first surface; a first excitation electrode overlying the first surface; a first extraction electrode that is extracted from the first excitation electrode and overlaps the third surface; It has the piezoelectric plate has a first recess recessed from the third surface toward the second side, the first recess is formed by cutting out a first edge portion of the third surface on a side of the first surface in a plan view, the first extraction electrode has a portion extending from the first surface to the third surface via the first recess, The first edge portion is a first partial edge portion located on one side in a first direction with respect to the vibration portion in a plan view; a second portion edge portion that is located on one side of the vibration portion in a second direction perpendicular to the first direction in a plan view and that forms a corner with the first portion edge portion, The first recess is formed by cutting out at least one of the first portion edge portion and the second portion edge portion at the corner portion, The third surface is a first region having the first edge; a second region located on an opposite side of the first surface with respect to the first region in a plan view and higher toward the first surface than the first region; the first extraction electrode reaches the second region via the first region, The piezoelectric plate has a through hole penetrating the piezoelectric plate in a thickness direction between the first region and the second region. Piezoelectric vibration element.

8. a second excitation electrode overlying the second surface; a second extraction electrode that is extracted from the second excitation electrode and overlaps the fourth surface; a third extraction electrode that is extracted from the first excitation electrode in a direction different from that of the first extraction electrode and that overlaps with the third surface; a fourth extraction electrode that is extracted from the second excitation electrode in a direction different from that of the second extraction electrode and that overlaps with the fourth surface; and the fixed portion surrounds the vibration portion in a plan view, the first extraction electrode has a portion located on a side of the first portion edge portion and a side of the second portion edge portion with respect to the first excitation electrode, the second extraction electrode has a portion located on a side of the first portion edge portion and on an opposite side to the second portion edge portion with respect to the second excitation electrode, the third extraction electrode has a portion located on a side opposite to the first portion edge portion side and on a side of the second portion edge portion side with respect to the first excitation electrode, The fourth extraction electrode has a portion located on the opposite side to the first portion edge portion and the opposite side to the second portion edge portion with respect to the second excitation electrode. The piezoelectric vibration element according to claim 4 .

9. A piezoelectric base plate having a vibration portion and a fixed portion which define different regions from each other in a plan view, the vibration portion having a first surface facing a first side and a second surface facing a second side opposite to the first side, the fixed portion having a third surface facing the first side and a fourth surface facing the second side, the third surface being higher on the first side than the first surface; a first excitation electrode overlying the first surface; a first extraction electrode that is extracted from the first excitation electrode and overlaps the third surface; It has the piezoelectric plate has a first recess recessed from the third surface toward the second side, the first recess is formed by cutting out a first edge portion of the third surface on a side of the first surface in a plan view, the first extraction electrode has a portion extending from the first surface to the third surface via the first recess, The first edge portion is a first partial edge portion located on one side in a first direction with respect to the vibration portion in a plan view; a second portion edge portion that is located on one side of the vibration portion in a second direction perpendicular to the first direction in a plan view and that forms a corner with the first portion edge portion, The first recess is formed by cutting out at least one of the first portion edge portion and the second portion edge portion at the corner portion, The first edge portion is a third portion edge portion facing the first portion edge portion with the vibration portion therebetween; a fourth partial edge portion facing the second partial edge portion across the vibration portion, The piezoelectric plate has a total of four recesses, including the first recess, recessed from the third surface toward the second side and cutting out the first edge, at four corners defined by the first portion edge portion, the second portion edge portion, the third portion edge portion, and the fourth portion edge portion in a plan view. Piezoelectric vibration element.

10. A piezoelectric base plate having a vibration portion and a fixed portion which define different regions from each other in a plan view, the vibration portion having a first surface facing a first side and a second surface facing a second side opposite to the first side, the fixed portion having a third surface facing the first side and a fourth surface facing the second side, the third surface being higher on the first side than the first surface; a first excitation electrode overlying the first surface; a first extraction electrode that is extracted from the first excitation electrode and overlaps the third surface; It has the piezoelectric plate has a first recess recessed from the third surface toward the second side, the first recess is formed by cutting out a first edge portion of the third surface on a side of the first surface in a plan view, the first extraction electrode has a portion extending from the first surface to the third surface via the first recess, When the size of the first recess in a direction along the first edge portion is referred to as a width, the width of the first recess at the height of the first edge portion is greater than the thickness of the vibration portion. Piezoelectric vibration element.

11. A piezoelectric base plate having a vibration portion and a fixed portion which define different regions from each other in a plan view, the vibration portion having a first surface facing a first side and a second surface facing a second side opposite to the first side, the fixed portion having a third surface facing the first side and a fourth surface facing the second side, the third surface being higher on the first side than the first surface; a first excitation electrode overlying the first surface; a first extraction electrode that is extracted from the first excitation electrode and overlaps the third surface; It has the piezoelectric plate has a first recess recessed from the third surface toward the second side, the first recess is formed by cutting out a first edge portion of the third surface on a side of the first surface in a plan view, the first extraction electrode has a portion extending from the first surface to the third surface via the first recess, a depth of the first recess from the first edge portion in a plan view, the depth at a height of the first edge portion being greater than a thickness of the vibration portion; Piezoelectric vibration element.

12. A piezoelectric base plate having a vibration portion and a fixed portion which define different regions from each other in a plan view, the vibration portion having a first surface facing a first side and a second surface facing a second side opposite to the first side, the fixed portion having a third surface facing the first side and a fourth surface facing the second side, the third surface being higher on the first side than the first surface; a first excitation electrode overlying the first surface; a first extraction electrode that is extracted from the first excitation electrode and overlaps the third surface; It has the piezoelectric plate has a first recess recessed from the third surface toward the second side, the first recess is formed by cutting out a first edge portion of the third surface on a side of the first surface in a plan view, the first extraction electrode has a portion extending from the first surface to the third surface via the first recess, When the size of the first recess in a direction along the first edge portion is referred to as a width, the width of the first recess at the height of the first edge portion is greater than the height from the first surface to the first edge portion. Piezoelectric vibration element.

13. A piezoelectric base plate having a vibration portion and a fixed portion which define different regions from each other in a plan view, the vibration portion having a first surface facing a first side and a second surface facing a second side opposite to the first side, the fixed portion having a third surface facing the first side and a fourth surface facing the second side, the third surface being higher on the first side than the first surface; a first excitation electrode overlying the first surface; a first extraction electrode that is extracted from the first excitation electrode and overlaps the third surface; It has the piezoelectric plate has a first recess recessed from the third surface toward the second side, the first recess is formed by cutting out a first edge portion of the third surface on a side of the first surface in a plan view, the first extraction electrode has a portion extending from the first surface to the third surface via the first recess, a depth of the first recess from the first edge portion in a plan view, the depth at a height of the first edge portion being greater than a height from the first surface to the first edge portion; Piezoelectric vibration element.

14. A piezoelectric base plate having a vibration portion and a fixed portion which define different regions from each other in a plan view, the vibration portion having a first surface facing a first side and a second surface facing a second side opposite to the first side, the fixed portion having a third surface facing the first side and a fourth surface facing the second side, the third surface being higher on the first side than the first surface; a first excitation electrode overlying the first surface; a first extraction electrode that is extracted from the first excitation electrode and overlaps the third surface; It has the piezoelectric plate has a first recess recessed from the third surface toward the second side, the first recess is formed by cutting out a first edge portion of the third surface on a side of the first surface in a plan view, the first extraction electrode has a portion extending from the first surface to the third surface via the first recess, The inner surface of the first recess is a bottom surface that is connected to the first surface and is flush with the first surface; an end surface located on the opposite side of the bottom surface from the first surface in a plan view, the end surface rising from the bottom surface to the first edge portion while inclining in a direction approaching the height of the first edge portion as it moves away from the bottom surface in a plan view; In a plan view, the bottom surface is recessed toward the third surface relative to the first edge portion. Piezoelectric vibration element.

15. A piezoelectric base plate having a vibration portion and a fixed portion which define different regions from each other in a plan view, the vibration portion having a first surface facing a first side and a second surface facing a second side opposite to the first side, the fixed portion having a third surface facing the first side and a fourth surface facing the second side, the third surface being higher on the first side than the first surface; a first excitation electrode overlying the first surface; a first extraction electrode that is extracted from the first excitation electrode and overlaps the third surface; It has the piezoelectric plate has a first recess recessed from the third surface toward the second side, the first recess is formed by cutting out a first edge portion of the third surface on a side of the first surface in a plan view, the first extraction electrode has a portion extending from the first surface to the third surface via the first recess, the piezoelectric plate has a fifth surface that connects the first surface and the first edge portion and is inclined so as to be positioned closer to the first side as it approaches the first edge portion, When the size of the first recess in a direction along the first edge portion is referred to as a width, the width of the first recess at the height of the first edge portion is greater than the length of the fifth surface from the first surface to the first edge portion in a plan view. Piezoelectric vibration element.

16. A piezoelectric base plate having a vibration portion and a fixed portion which define different regions from each other in a plan view, the vibration portion having a first surface facing a first side and a second surface facing a second side opposite to the first side, the fixed portion having a third surface facing the first side and a fourth surface facing the second side, the third surface being higher on the first side than the first surface; a first excitation electrode overlying the first surface; a first extraction electrode that is extracted from the first excitation electrode and overlaps the third surface; It has the piezoelectric plate has a first recess recessed from the third surface toward the second side, the first recess is formed by cutting out a first edge portion of the third surface on a side of the first surface in a plan view, the first extraction electrode has a portion extending from the first surface to the third surface via the first recess, the piezoelectric plate has a fifth surface that connects the first surface and the first edge portion and is inclined so as to be positioned closer to the first side as it approaches the first edge portion, a depth of the first recess from the first edge portion in a plan view, the depth at a height of the first edge portion being greater than a length of the fifth surface from the first surface to the first edge portion in a plan view; Piezoelectric vibration element.

17. The piezoelectric vibration element according to any one of claims 1 to 16, a package in which the piezoelectric vibration element is mounted; A piezoelectric device having a

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