Piezoelectric vibration piece and piezoelectric vibration device

Abstract

A crystal resonator element (10) is provided with a resonator part (11), an outer frame part (12), and a holding part (13), a cut-out part (10a) is provided between the resonator part (11) and the outer frame part (12), and an electrode formed on one main surface is connected to an electrode formed on the other main surface via an internal wiring (17) formed on the inner wall surface of the outer frame part (12). A region sandwiched between the inner wall surface of the outer frame portion (12) and the outer wall surface of the vibrating portion (11) is defined as a first region (A1). Among areas remaining after the first area (A1) is removed from the space of the cut-out part (10a), the area sandwiched between the inner wall surface of the outer frame part (12) and the outer wall surface of the holding part (13) is used as a second area (A2), and the area sandwiched between the inner wall surfaces of the outer frame part (12) is used as a third area (A3). The internal wiring (17) is formed at a position facing at least one of the second region (A2) and the third region (A3) on the inner wall surface of the outer frame portion (12).

Description

Technical Field

[0001] The present invention relates to a piezoelectric vibration piece and a piezoelectric vibration device including the piezoelectric vibration piece. Background Art

[0002] In recent years, the operating frequencies of various electronic devices have been increasing, and the packages have been becoming increasingly smaller (especially lower profile). Consequently, crystal oscillator devices (such as crystal resonators and crystal oscillators) are required to keep pace with these increases in frequency and package size.

[0003] As a crystal resonator device suitable for miniaturization and low profile, a so-called sandwich structure crystal resonator device is known. The shell of the sandwich structure crystal resonator device is composed of a package body that is approximately rectangular. The package body includes a first sealing member and a second sealing member made of, for example, glass or crystal, and a crystal resonator plate with excitation electrodes formed on both main surfaces. The first sealing member and the second sealing member are stacked and bonded via the crystal resonator plate. In this way, the vibrating portion of the crystal resonator plate arranged inside the package body (internal space) is hermetically sealed by the first sealing member and the second sealing member (for example, refer to Patent Document 1).

[0004] In the piezoelectric vibrating reed described above, if a through-hole, for example, is provided in the outer frame to connect an electrode formed on one principal surface to an electrode formed on the other principal surface, space for the through-hole, etc., is required, making it difficult to accommodate miniaturization. Furthermore, as miniaturization decreases, the distance between the vibrating portion and the outer frame decreases, potentially causing the vibrating portion to come into contact with wiring formed in the outer frame, potentially leading to wire breakage.

[0005] [Patent Document 1]: Japanese Patent Application Laid-Open No. 2010-252051 Summary of the Invention

[0006] In view of the above circumstances, an object of the present invention is to provide a piezoelectric vibrating piece that can cope with miniaturization and can maintain stable electrical characteristics, and a piezoelectric vibrating device including the piezoelectric vibrating piece.

[0007] As a technical solution to the above-mentioned technical problems, the present invention adopts the following structure. Specifically, the present invention provides a rectangular piezoelectric vibrating reed having a first excitation electrode formed on one principal surface of a substrate and a second excitation electrode forming a pair with the first excitation electrode formed on the other principal surface of the substrate. The piezoelectric vibrating reed includes a rectangular vibrating portion, an outer frame portion surrounding the outer periphery of the vibrating portion, and a holding portion connecting a portion of the vibrating portion to a portion of the outer frame portion. A cutout portion formed by cutting out the substrate is provided between the vibrating portion and the outer frame portion. The electrodes formed on the one principal surface of the substrate are electrically connected to the electrodes formed on the other principal surface of the substrate via internal wiring formed on the inner wall surface of the outer frame portion. Within the space of the cutout portion, an area sandwiched between the inner wall surface of the outer frame portion and the outer wall surface of the vibrating portion is defined as a first area. Within the area remaining after removing the first area from the space of the cutout portion, an area sandwiched between the inner wall surface of the outer frame portion and the outer wall surface of the holding portion is defined as a second area, and an area sandwiched between the inner wall surfaces of the outer frame portion is defined as a third area. The internal wiring is formed on the inner wall surface of the outer frame portion at a position facing at least one of the second and third areas. Here, as electrodes formed on one main surface and the other main surface of the substrate, there are, for example, electrodes of an annular sealing portion (sealing path) that hermetically seals the vibration portion of the piezoelectric vibration piece, wiring electrodes connected to the ground, lead electrodes led from the first excitation electrode and the second excitation electrode, and wiring electrodes connected to the IC possessed by the piezoelectric oscillator.

[0008] Based on the above structure, it is possible to cope with the miniaturization of the piezoelectric vibrating piece and maintain stable electrical characteristics. Specifically, since the electrodes formed on one main surface are connected to the electrodes formed on the other main surface through internal wiring, there is no need to form through holes in the outer frame, which ensures the effective area of ​​the vibrating part while also coping with the miniaturization of the piezoelectric vibrating piece. In addition, the inner wall surface of the outer frame facing (contacting) the second and third regions is cut away to a greater width than the inner wall surface of the outer frame facing (contacting) the adjacent first region, thereby ensuring space between the opposing wall surfaces. This prevents the vibrating part from contacting the internal wiring, reducing the risk of wire breakage. Furthermore, the internal wiring can be easily and reliably formed on the inner wall surface of the outer frame. In this case, in the photolithography process used to form the internal wiring on the inner wall surface of the outer frame, the protective coating on the inner wall surface of the outer frame and the outer wall surface of the vibrating part can be reliably removed, thereby reliably forming the internal wiring on the inner wall surface of the outer frame. Therefore, the electrodes formed on one main surface and the electrodes formed on the other main surface can be electrically connected stably and reliably, thereby preventing the electrical characteristics of the piezoelectric vibrating piece from being degraded and preventing defective products from being generated.

[0009] In the piezoelectric vibrating piece of the above structure, it is preferred that the inner wall surface of the outer frame portion is configured to be rectangular and annular when viewed from above, a notch portion sunken into the outer frame portion is formed at a corner of the inner wall surface when viewed from above, and the internal wiring is formed on the inner wall surface of the notch portion.

[0010] With the piezoelectric vibrating piece structured as described above, the inner wall surface of the notch is formed as an inclined surface, making it possible to reduce the risk of internal wiring breakage. Furthermore, since the notch is recessed into the outer frame, the effective area of ​​the vibrating portion is ensured, resulting in a compact piezoelectric vibrating piece with stable electrical characteristics.

[0011] In addition, the present invention is a piezoelectric vibration device having a piezoelectric vibration piece having the structure described above, characterized in that: a first sealing member covering the first excitation electrode of the piezoelectric vibration piece and a second sealing member covering the second excitation electrode of the piezoelectric vibration piece are provided, and the first sealing member is bonded to the piezoelectric vibration piece, and the second sealing member is bonded to the piezoelectric vibration piece, so that an internal space is provided in which the vibration portion of the piezoelectric vibration piece including the first excitation electrode and the second excitation electrode is hermetically sealed.

[0012] The piezoelectric vibrating device with the above-described structure can achieve the same effects as the piezoelectric vibrating reed described above. Furthermore, since the internal wiring is not exposed on the external surface of the piezoelectric vibrating device package, the internal wiring is not likely to be broken or scratched by contact during assembly or transportation.

[0013] In the piezoelectric vibrator device having the above structure, preferably, a grounding electrode formed on one of the two principal surfaces of the first sealing member is electrically connected to an external electrode terminal formed on the principal surface of the second sealing member that does not face the internal space via the internal wiring. This structure allows the grounding electrode to be reliably connected to the external electrode terminal via the internal wiring, thereby improving the shielding performance of the grounding electrode.

[0014] In the piezoelectric vibrating device having the above structure, preferably, an annular sealing portion for airtightly sealing the vibrating portion of the piezoelectric vibrating reed is provided between the first sealing member and the piezoelectric vibrating reed, and between the second sealing member and the piezoelectric vibrating reed, respectively, and each of the sealing portions is electrically connected to the internal wiring. With this structure, the sealing portions can be reliably connected to each other via the internal wiring.

[0015] In the piezoelectric vibrating device of the above structure, preferably, only one retaining portion is provided, extending from a corner of the vibrating portion toward the outer frame portion. This structure ensures that the second and third regions of the plurality of cutouts are maintained, thereby achieving a structure that improves the stability of internal wiring conduction while minimizing the suppression of the main vibration of the piezoelectric vibrating piece.

[0016] In the piezoelectric resonator device with the above structure, the piezoelectric resonator piece is preferably an AT-cut crystal resonator piece, and the internal wiring is preferably formed on the inner wall surface of the outer frame portion parallel to the Z'-axis direction of the AT-cut. Here, the inner wall surface of the outer frame portion parallel to the X-axis direction of the AT-cut forms an inclined surface during the wet etching process used to form the cutout portion, which easily creates sharp angles and may cause breakage when forming the internal wiring. However, the inner wall surface of the outer frame portion parallel to the Z'-axis direction of the AT-cut is less likely to have such sharp angles, making it easier to form the internal wiring, thereby reducing the risk of breakage.

[0017] <Effects of the Invention>

[0018] The piezoelectric vibrating piece and the piezoelectric vibrating device according to the present invention can cope with miniaturization while maintaining stable electrical characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 1 is a diagram schematically showing the general configuration of a crystal resonator according to this embodiment.

[0020] Figure 2 This is a schematic plan view of the first principal surface side of the first sealing member of the crystal resonator.

[0021] Figure 3 This is a schematic plan view of the second principal surface side of the first sealing member of the crystal resonator.

[0022] Figure 4 It is a schematic plan view of the first principal surface side of the crystal resonator piece according to this embodiment.

[0023] Figure 5 This is a schematic plan view of the second principal surface side of the crystal resonator piece according to this embodiment.

[0024] Figure 6 This is a schematic plan view of the first principal surface side of the second sealing member of the crystal resonator.

[0025] Figure 7 This is a schematic plan view of the second principal surface side of the second sealing member of the crystal resonator.

[0026] Figure 8 This is the equivalent of the crystal resonator piece according to the first embodiment. Figure 4 Picture.

[0027] Figure 9 This is equivalent to the first sealing member according to another embodiment 2. Figure 3 Picture.

[0028] Figure 10 This is the equivalent of the crystal resonator piece according to the third embodiment. Figure 4 Picture.

[0029] Figure 11 This is the equivalent of the crystal resonator piece according to the third embodiment. Figure 5 Picture.

[0030] <Description of Reference Numerals>

[0031] 10 Crystal resonator

[0032] 10a Resection

[0033] 11. Vibration unit

[0034] 12 outer frame

[0035] 13. Maintaining part

[0036] 17 Internal Wiring

[0037] 100 Crystal Resonator

[0038] 111 first excitation electrode

[0039] 112 second excitation electrode

[0040] A1 First Area

[0041] A2 Second Area

[0042] A3 Third Area DETAILED DESCRIPTION

[0043] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following embodiments, a case where the piezoelectric vibration device to which the present invention is applied is a crystal resonator will be described.

[0044] First, the basic structure of the crystal resonator 100 according to this embodiment will be described. Figure 1As shown, the crystal resonator 100 is constructed to include a crystal vibrating plate (piezoelectric vibrating plate) 10, a first sealing member 20, and a second sealing member 30. In the crystal resonator 100, the crystal vibrating plate 10 is bonded to the first sealing member 20, and the crystal vibrating plate 10 is bonded to the second sealing member 30, thereby forming a package having a sandwich structure that is approximately rectangular. That is, in the crystal resonator 100, the first sealing member 20 and the second sealing member 30 are bonded to the two main surfaces of the crystal vibrating plate 10, respectively, thereby forming an internal space (cavity) of the package. The vibrating portion 11 (see FIG. 1 ) is located in the vibrating portion 11. Figure 4 、 Figure 5 ) is hermetically sealed in the internal space.

[0045] The crystal resonator 100 according to this embodiment has a package size of, for example, 1.0×0.8 mm, achieving miniaturization and low profile. Furthermore, the crystal resonator 100 is electrically connected to an external circuit board (not shown) provided externally by solder.

[0046] Below, refer to Figures 1 to 7 The following describes the individual components of the crystal resonator 100, namely, the crystal vibrating plate 10, the first sealing member 20, and the second sealing member 30. Here, the individual components that have not yet been bonded together and are each a single structure will be described. Figures 2 to 7 Only one structural example of each of the crystal resonator piece 10 , the first sealing member 20 , and the second sealing member 30 is shown, and the present invention is not limited thereto.

[0047] like Figure 4 、 Figure 5 As shown, the crystal resonator plate 10 is a piezoelectric substrate made of quartz crystal, and its two main surfaces (first main surface 101 and second main surface 102) are processed (mirror-finished) to be flat and smooth. In this embodiment, an AT-cut crystal plate that performs thickness shear vibration is used as the crystal resonator plate 10. Figure 4 、 Figure 5In the illustrated crystal resonator plate 10, the two principal surfaces (101, 102) of the crystal resonator plate 10 define the XZ' plane. In this XZ' plane, the direction parallel to the width (short side) of the crystal resonator plate 10 is the X-axis direction, and the direction parallel to the length (long side) of the crystal resonator plate 10 is the Z'-axis direction. AT-cutting refers to a processing method in which the three crystal axes of an artificial crystal—the electrical axis (X-axis), the mechanical axis (Y-axis), and the optical axis (Z-axis)—are cut at an angle of 35°15' relative to the Z-axis in the X-axis direction. In AT-cut crystal plates, the X-axis coincides with the crystal axis of the crystal. The Y' and Z' axes coincide with axes tilted approximately 35°15' from the Y and Z axes of the crystal, respectively (these cutting angles can be slightly varied within the range for adjusting the frequency-temperature characteristics of the AT-cut crystal resonator plate). The Y' and Z' axes correspond to the cutting directions used when cutting AT-cut crystal plates.

[0048] A pair of excitation electrodes (a first excitation electrode 111 and a second excitation electrode 112) are formed on both principal surfaces (101, 102) of the crystal resonator plate 10. The crystal resonator plate 10 includes a vibrating portion 11 having a substantially rectangular shape, an outer frame portion 12 surrounding the outer periphery of the vibrating portion 11, and a retaining portion 13 that holds the vibrating portion 11 by connecting the vibrating portion 11 to the outer frame portion 12. In other words, the crystal resonator plate 10 has a structure in which the vibrating portion 11, the outer frame portion 12, and the retaining portion 13 are integrally formed. The retaining portion 13 extends (protrudes) in the -Z' direction from only one corner of the vibrating portion 11 located in the +X direction and the -Z' direction to the outer frame portion 12. Furthermore, a cutout portion 10a is provided between the vibrating portion 11 and the outer frame portion 12, formed by cutting out the crystal resonator plate 10. In this embodiment, the crystal resonator piece 10 has only one retaining portion 13 connecting the vibrating portion 11 to the outer frame portion 12. The cutout portion 10a is formed continuously to surround the outer periphery of the vibrating portion 11. In this embodiment, the outer frame portion 12 of the crystal resonator piece 10 is not provided with through-holes or castellations. The crystal resonator piece 10 is constructed without any through-holes other than the cutout portion 10a.

[0049] The first excitation electrode 111 is provided on the first principal surface 101 side of the vibrating portion 11, and the second excitation electrode 112 is provided on the second principal surface 102 side of the vibrating portion 11. Lead wiring (lead-out electrodes) for connecting these excitation electrodes to external electrode terminals are connected to the first excitation electrodes 111 and the second excitation electrodes 112. The first lead wiring 113 extends from the first excitation electrode 111 and passes through the retaining portion 13 to connect to a connection bonding pattern 12a formed on the first principal surface 101 side of the outer frame portion 12. Furthermore, the connection bonding pattern 12a is connected to a connection bonding pattern 12e formed on the second principal surface 102 side of the outer frame portion 12 via an internal wiring 12g formed on the inner wall surface of the outer frame portion 12. The internal wiring 12g is formed on the inner wall surface of the outer frame portion 12 that is parallel to the X-axis direction and on the -Z' side. In this case, the internal wiring 12g is formed in a V-shaped recessed portion formed on the inner wall surface of the outer frame portion 12 when viewed from above. By forming a V-shaped recess on the inner wall surface of the outer frame portion 12, the internal wiring 12g can be formed parallel to directions other than the X-axis direction of the AT cut. Therefore, even if an inclined surface is formed during the wet etching process, no portion other than an acute angle will be present, thereby reducing the risk of wire breakage. The second lead wiring 114 extends from the second excitation electrode 112 and passes through the retaining portion 13 to connect to the connection bonding pattern 12d formed on the second main surface 102 side of the outer frame portion 12.

[0050] A vibration plate-side sealing portion is provided on each of the two principal surfaces (the first principal surface 101 and the second principal surface 102) of the crystal resonator piece 10, for bonding the crystal resonator piece 10 to the first sealing member 20 and the second sealing member 30. A first vibration plate-side bonding pattern 121 is formed as the vibration plate-side sealing portion on the first principal surface 101, and a second vibration plate-side bonding pattern 122 is formed as the vibration plate-side sealing portion on the second principal surface 102. The first vibration plate-side bonding pattern 121 and the second vibration plate-side bonding pattern 122 are provided on the outer frame portion 12 and are formed into an annular shape when viewed from above. The outer periphery of the first vibration plate-side bonding pattern 121 is close to the outer periphery of the first principal surface 101 of the crystal resonator piece 10 (outer frame portion 12). The outer periphery of the second vibration plate-side bonding pattern 122 is close to the outer periphery of the second principal surface 102 of the crystal resonator piece 10 (outer frame portion 12). In this embodiment, the first vibration plate-side bonding pattern 121 and the second vibration plate-side bonding pattern 122 are connected via internal wiring 17 formed on the inner wall surface of the outer frame portion 12. Internal wiring 17 is provided on the inner wall surface of the outer frame portion 12 that is parallel to the Z′ axis direction and on the inner wall surface on the -X direction side, and is provided on the inner wall surface perpendicular to the inner wall surface provided with the aforementioned internal wiring 12g. Furthermore, connection bonding patterns 12b and 12c are formed on the first principal surface 101 of the outer frame portion 12, and a connection bonding pattern 12f is formed on the second principal surface 102 of the outer frame portion 12.

[0051] like Figure 2 、 Figure 3 As shown, the first sealing member 20 is a rectangular parallelepiped substrate composed of an AT-cut crystal piece. The second main surface 202 of the first sealing member 20 (the surface bonded to the crystal vibrating plate 10) is processed (mirror-finished) to be a flat and smooth surface. Although the first sealing member 20 does not have a vibrating portion, by using an AT-cut crystal piece like the crystal vibrating plate 10, the thermal expansion coefficient of the crystal vibrating plate 10 and the first sealing member 20 can be made the same, thereby suppressing thermal deformation in the crystal resonator 100. In addition, the directions of the X-axis, Y-axis, and Z' axis of the first sealing member 20 are also the same as those of the crystal vibrating plate 10. In this embodiment, the first sealing member 20 adopts a structure without through holes or castellations, which can significantly shorten the manufacturing process of the first sealing member 20. In addition, the corrosion resistance of the first sealing member 20 can be improved by eliminating the infiltration path for moisture to penetrate into the internal space of the package.

[0052] A sealing component-side first bonding pattern 24 is formed on the second principal surface 202 of the first sealing member 20 as a sealing component-side first sealing portion for bonding to the crystal vibrating piece 10. The sealing component-side first bonding pattern 24 is configured to be annular when viewed from above. The outer peripheral edge of the sealing component-side first bonding pattern 24 is close to the outer peripheral edge of the second principal surface 202 of the first sealing member 20. In addition, connection bonding patterns (22a, 22b, 22c) are formed on the second principal surface 202 of the first sealing member 20 for bonding to the connection bonding patterns (12a, 12b, 12c) formed on the first principal surface 101 of the outer frame portion 12 of the crystal vibrating piece 10.

[0053] like Figure 6 、 Figure 7 As shown, the second sealing member 30 is a rectangular parallelepiped substrate made of an AT-cut crystal sheet. The first principal surface 301 of the second sealing member 30 (the surface that bonds to the crystal resonator plate 10) is machined (mirror-finished) to a flat and smooth surface. Preferably, the second sealing member 30 also uses the same AT-cut crystal sheet as the crystal resonator plate 10, and the directions of the X-axis, Y-axis, and Z′-axis are the same as those of the crystal resonator plate 10.

[0054] A sealing component-side second bonding pattern 31 is formed on the first principal surface 301 of the second sealing member 30 as a sealing component-side second sealing portion for bonding to the crystal resonator plate 10. The sealing component-side second bonding pattern 31 is configured to be annular when viewed from above. The outer periphery of the sealing component-side second bonding pattern 31 is close to the outer periphery of the first principal surface 301 of the second sealing member 30. In addition, connection bonding patterns (34a, 34b, 34c) are formed on the first principal surface 301 of the second sealing member 30 for bonding to the connection bonding patterns (12d, 12e, 12f) formed on the second principal surface 102 of the outer frame portion 12 of the crystal resonator plate 10. The connection bonding patterns 34a and 34c are connected by a wiring pattern 35 extending in the Z′ axis direction.

[0055] Four external electrode terminals 32 are provided on the second principal surface 302 (the outer principal surface not facing the crystal resonator plate 10) of the second sealing member 30. These terminals are used to electrically connect to an external circuit board located outside the crystal resonator 100. The external electrode terminals 32 are formed in a substantially rectangular shape and are located at the four corners (corners) of the second principal surface 302 of the second sealing member 30. The external electrode terminals 32 are positioned so as to overlap the outer frame portion 12 of the crystal resonator plate 10 when viewed from above.

[0056] like Figure 6 、 Figure 7As shown, three through holes (33a, 33b, 33c) are formed on the second sealing member 30, which pass through the first main surface 301 and the second main surface 302. The through holes (33a, 33b, 33c) are arranged in the four corners (corner) of the second sealing member 30. In the through holes (33a, 33b, 33c), along the inner wall surface of each of the through holes (33a, 33b, 33c), a through electrode is formed to achieve conduction between the electrodes formed on the first main surface 301 and the second main surface 302. Through the through electrodes formed on the inner wall surface of the through holes (33a, 33b, 33c), the electrode (connection bonding pattern) formed on the first main surface 301 is connected to the external electrode terminal 32 formed on the second main surface 302. In addition, the central portion of each of the through holes (33a, 33b, 33c) becomes a hollow through portion that passes through the first main surface 301 and the second main surface 302.

[0057] In the crystal resonator 100 including the crystal vibrating plate 10, the first sealing member 20, and the second sealing member 30 of the above-mentioned structure, the crystal vibrating plate 10 and the first sealing member 20 are diffusion-bonded in a state where the first bonding pattern 121 on the vibration plate side and the first bonding pattern 24 on the sealing member side overlap, and the crystal vibrating plate 10 and the second sealing member 30 are diffusion-bonded in a state where the second bonding pattern 122 on the vibration plate side and the second bonding pattern 31 on the sealing member side overlap, thereby producing Figure 1 As shown in the sandwich structure package, the internal space of the package, that is, the space for accommodating the vibration part 11 is hermetically sealed.

[0058] At this time, the aforementioned connection bonding patterns are also diffusion-bonded in an overlapping state. Thus, through the bonding of the connection bonding patterns, electrical conduction is achieved between the first excitation electrode 111, the second excitation electrode 112, and the external electrode terminals (32, 32) in the crystal resonator 100. Specifically, the first excitation electrode 111 is connected to the external electrode terminal 32 via the first lead-out wiring 113, the internal wiring 12g, and the through-electrode of the through-hole 33a. The second excitation electrode 112 is connected to the external electrode terminal 32 via the second lead-out wiring 114, the wiring pattern 35, and the through-electrode of the through-hole 33b.

[0059] In crystal resonator 100, the various bonding patterns are preferably formed by stacking multiple layers on a crystal sheet and then evaporating or sputtering Ti (titanium) and Au (gold) layers from the bottom. Furthermore, it is preferred that other wiring or electrodes formed on crystal resonator 100 also have the same structure as the bonding pattern, allowing the bonding pattern, wiring, and electrodes to be patterned simultaneously.

[0060] In the crystal resonator 100 constructed as described above, the sealing portion (sealing path 15, sealing path 16) that hermetically seals the vibrating portion 11 of the crystal vibrating plate 10 is formed to be annular in plan view. The sealing path 15 is formed by diffusion bonding (Au-Au bonding) between the first bonding pattern 121 on the vibration plate side and the first bonding pattern 24 on the sealing component side. The outer edge of the sealing path 15 is approximately rectangular, and the outer periphery of the sealing path 15 is in close contact with the outer periphery of the package. Similarly, the sealing path 16 is formed by diffusion bonding (Au-Au bonding) between the second bonding pattern 122 on the vibration plate side and the second bonding pattern 31 on the sealing component side. The outer edge of the sealing path 16 is approximately rectangular, and the outer periphery of the sealing path 16 is in close contact with the outer periphery of the package. The sealing paths 15, 16 are not electrically connected to the electrical conduction paths between the first excitation electrode 111, the second excitation electrode 112 and the external electrode terminal 32, the external electrode terminal 32. Specifically, the sealing path 15 is connected to the sealing path 16 via the internal wiring 17 , and the sealing path 16 is grounded via a through electrode of the through hole 33 c (ground connection is made using a part of the external electrode terminal 32 ).

[0061] In the crystal resonator 100 in which the sealing paths (15, 16) are formed by such diffusion bonding, a gap of 1.00 μm or less exists between the first sealing member 20 and the crystal resonator plate 10, and a gap of 1.00 μm or less exists between the second sealing member 30 and the crystal resonator plate 10. Specifically, the thickness of the sealing path 15 between the first sealing member 20 and the crystal resonator plate 10 is 1.00 μm or less, and the thickness of the sealing path 16 between the second sealing member 30 and the crystal resonator plate 10 is 1.00 μm or less (specifically, 0.15 μm to 1.00 μm in the Au-Au bonding of this embodiment). Furthermore, as a comparative example, the thickness of a conventional metal paste encapsulant using Sn is 5 μm to 20 μm.

[0062] In the present embodiment, in the crystal vibrator plate 10 of the above-mentioned structure, a cutout portion 10a formed by cutting out the substrate is provided between the vibration portion 11 and the outer frame portion 12, and the electrode (sealed path 15) formed on the first main surface 101 of the substrate is electrically connected to the electrode (sealed path 16) formed on the second main surface 102 of the substrate via the internal wiring 17 formed on the inner wall surface of the outer frame portion 12. In the space of the cutout portion 10a, if the area sandwiched between the inner wall surface of the outer frame portion 12 and the outer wall surface of the vibration portion 11 is taken as the first area A1; in the area remaining after removing the first area A1 from the space of the cutout portion 10a, if the area sandwiched between the inner wall surface of the outer frame portion 12 and the outer wall surface of the retaining portion 13 is taken as the second area A2, and the area sandwiched between the inner wall surfaces of the outer frame portion 12 is taken as the third area A3, then the internal wiring 17 is formed on the inner wall surface of the outer frame portion 12 at a position facing at least one of the second area A2 and the third area A3. For this point, refer to Figure 4 Provide explanation.

[0063] like Figure 4 As shown, the space of the cutout portion 10a is divided into a plurality of regions ( Figure 4 There are eight regions in the figure. Lines L1 and L2 are parallel to the Z′-axis direction, and lines L3 and L4 are parallel to the X-axis direction. The region sandwiched between the inner wall surface of the outer frame portion 12 and the outer wall surface of the vibrating portion 11 is the first region A1. The first region A1 is provided in four locations that are in contact with the outer wall surface of the vibrating portion 11. The first region A1 is a region that faces each other in the X-axis direction and the Z′-axis direction, sandwiching the vibrating portion 11. The first region A1 is provided in a region other than the space at the four corners of the cutout portion 10a.

[0064] Furthermore, the area remaining after removing the first area A1 from the space of the cutout portion 10a, sandwiched between the inner wall surface of the outer frame portion 12 and the outer wall surface of the retaining portion 13, is defined as the second area A2. The second area A2 is provided at two locations on the -Z' side of the space at the four corners of the cutout portion 10a. The area remaining after removing the first area A1 from the space of the cutout portion 10a, sandwiched between the inner wall surfaces of the outer frame portion 12, is defined as the third area A3. The third area A3 is provided at two locations on the +Z' side of the space at the four corners of the cutout portion 10a.

[0065] In this embodiment, internal wiring 17 is formed on the inner wall surface of the outer frame portion 12, at a position facing one third area A3. Specifically, internal wiring 17 is formed at a position facing the third area A3 at a corner facing the -X and +Z' directions of the cutout portion 10a. Internal wiring 17 is formed on the inner wall surface of the outer frame portion 12 parallel to the Z' axis. The retaining portion 13 and internal wiring 17 are arranged at diagonal positions within the space of the cutout portion 10a.

[0066] Based on this embodiment, the crystal vibrator piece 10 can accommodate miniaturization of the crystal vibrator piece 10 while maintaining stable electrical characteristics. Specifically, since the electrodes (sealed paths 15) formed on the first principal surface 101 of the outer frame portion 12 and the electrodes (sealed paths 16) formed on the second principal surface 102 are connected via internal wiring 17, there is no need to form through-holes or the like in the outer frame portion 12. This ensures the effective area of ​​the vibrator portion 11 while also accommodating miniaturization of the crystal vibrator piece 10. Furthermore, the inner wall surface of the outer frame portion 12 facing (contacting) the third area A3 is configured with a larger cutout width than the inner wall surface of the outer frame portion 12 facing (contacting) the first area A1 (adjacent to the third area A3), thereby ensuring space between the opposing wall surfaces. Therefore, by forming the internal wiring 17 in a position that does not face the vibrator portion 11, the vibrator portion 11 can be prevented from contacting the internal wiring 17, thereby reducing the risk of disconnection.

[0067] Furthermore, internal wiring 17 can be easily and reliably formed on the inner wall surface of the outer frame portion 12. In the photolithography process for forming internal wiring 17 on the inner wall surface of the outer frame portion 12, if internal wiring 17 is formed on the inner wall surface of an area where the distance between the vibrating portion 11 and the outer frame portion 12 is small (e.g., the first area A1), there is a possibility that the protective coating may remain in this area, making it difficult to form internal wiring 17. However, according to this embodiment, the photolithography process for forming internal wiring 17 on the inner wall surface of the outer frame portion 12 can reliably remove the protective coating on the inner wall surface of the outer frame portion 12 and the outer wall surface of the vibrating portion 11, allowing internal wiring 17 to be reliably formed on the inner wall surface of the outer frame portion 12. Consequently, the electrodes (sealed paths 15) formed on the first principal surface 101 of the outer frame portion 12 and the electrodes (sealed paths 16) formed on the second principal surface 102 can be stably and reliably electrically connected, thereby preventing degradation of the electrical characteristics of the crystal vibrating piece 10 and the occurrence of defective products.

[0068] The crystal resonator 100 including the crystal resonator plate 10 described above can also achieve the same effects as those of the crystal resonator plate 10 described above. In addition, since the internal wiring 17 is not exposed to the external surface of the package of the crystal resonator 100, the internal wiring 17 is not broken or scratched due to contact during assembly or transportation.

[0069] In this embodiment, an annular sealing path 15 formed on the first principal surface 101 side of the outer frame portion 12 of the crystal resonator piece 10 and an annular sealing path 16 formed on the second principal surface 102 side of the outer frame portion 12 are in contact with each other via internal wiring 17. This structure allows the sealing paths 15 and 16 to be reliably connected to each other via internal wiring 17, and the sealing paths 15 and 16 can be reliably grounded, thereby improving the shielding performance of the sealing paths 15 and 16.

[0070] In this embodiment, only one holding portion 13 is provided, extending from a corner of the vibrating portion 11 toward the outer frame portion 12. This structure ensures that the second area A2 and the third area A3 of the plurality of cutouts 10a are formed, thereby achieving a structure that improves the stability of conduction using the internal wiring 17 while minimizing the suppression of the main vibration of the crystal vibrating piece 10.

[0071] Furthermore, internal wiring 17 is formed on the inner wall surface of the outer frame portion 12 parallel to the Z'-axis direction of the AT cut. Here, the inner wall surface of the outer frame portion 12 parallel to the X-axis direction of the AT cut forms an inclined surface during the wet etching process used to form the cutout portion 10a, which easily creates sharp angles. This can lead to the possibility of wire breakage when forming internal wiring. However, the inner wall surface of the outer frame portion 12 parallel to the Z'-axis direction of the AT cut is less likely to have such sharp angles, making it easier to form internal wiring 17 and reducing the risk of wire breakage. Furthermore, internal wiring 17 is preferably formed at a predetermined distance from the end of the inner wall surface of the outer frame portion 12 parallel to the Z'-axis direction of the AT cut.

[0072] The embodiments disclosed herein are merely illustrative of various aspects and are not to be construed as limiting. Therefore, the technical scope of the present invention cannot be interpreted solely based on the embodiments described above but must be defined based on the claims. Furthermore, all modifications within the meaning and scope equivalent to the claims are intended to be encompassed.

[0073] In the above embodiment, the internal wiring 17 is set at the position of the third area A3 on the corner facing the -X direction side and the +Z′ direction side of the cut-off portion 10a, but the present invention is not limited to this. The internal wiring 17 can also be set at the position of the third area A3 on the corner facing the +X direction side and the +Z′ direction side of the cut-off portion 10a, or the internal wiring 17 can also be set at the position of the second area A2 on the corner facing the -X direction side and the -Z′ direction side of the cut-off portion 10a.

[0074] Furthermore, in the above embodiment, only one internal wiring 17 is provided, but this is not limiting. Multiple internal wirings 17 may also be provided. For example, internal wirings 17 may be provided at two locations on the inner wall surface of the outer frame portion 12 facing the third area A3. Alternatively, internal wirings 17 may be provided at a location on the inner wall surface of the outer frame portion 12 facing the second area A2 and at a location facing the third area A3. In this case, internal wirings 17 may be provided on the inner wall surface of the outer frame portion 12 parallel to the Z′ axis, on the inner wall surface parallel to the X axis, or on both the inner wall surface parallel to the X axis and the inner wall surface parallel to the Z′ axis. When internal wirings 17 are provided on the inner wall surface parallel to the X axis, it is preferably formed in a V-shaped recess provided on the inner wall surface of the outer frame portion 12, similar to the case of internal wirings 12g described above.

[0075] Figure 8 In the illustrated example, three internal wirings 17 are provided on the inner wall surface of the outer frame portion 12. Specifically, the first internal wiring 17 is provided on the inner wall surface of the outer frame portion 12, which is parallel to the Z'-axis direction and on the -X-direction side, and is located in the second area A2 facing the corner of the cutout portion 10a on the -X-direction and -Z'-direction sides. Furthermore, the second internal wiring 17 is provided on the inner wall surface of the outer frame portion 12, which is parallel to the Z'-axis direction and on the +X-direction side, and is located in the third area A3 facing the corner of the cutout portion 10a on the +X-direction and +Z'-direction sides. Furthermore, the third internal wiring 17 is provided on the inner wall surface of the outer frame portion 12, which is parallel to the X-axis direction and on the +Z'-direction side, and is located in the third area A3 facing the corner of the cutout portion 10a on the -X-direction and +Z'-direction sides. The third internal wiring 17 is provided in a V-shaped recessed portion provided on the inner wall surface on the +Z′ direction side of the outer frame portion 12 .

[0076] In the above embodiment, the electrodes of the annular sealed paths (15, 16) formed on the first main surface 101 side and the second main surface 102 side of the outer frame portion 12 of the crystal vibrating piece 10 are connected to each other through the internal wiring 17. However, this is not limited to this, and other electrodes can also be connected using the internal wiring 17. For example, the internal wiring 17 can also be connected to the first lead wiring 113 led out from the first excitation electrode 111 and the second lead wiring 114 led out from the second excitation electrode 112. In addition, for example, Figure 9 As shown, the internal wiring 17 is connected to the wiring electrode connected to the ground.

[0077] Figure 9In the example shown in FIG. 2 , a grounding electrode 25 is formed on the second principal surface 202 of the first sealing member 20. The grounding electrode 25 is connected to the sealing path 15 on the first principal surface 101 side of the outer frame portion 12 of the crystal resonator piece 10 and is further connected to the sealing path 16 on the second principal surface 102 side of the outer frame portion 12 of the crystal resonator piece 10 via the internal wiring 17. Furthermore, the sealing path 16 is connected to the external electrode terminal 32 formed on the second principal surface 302 of the second sealing member 30 via the through-electrode of the through-hole 33 c. With this structure, the grounding electrode 25 can be reliably connected to the external electrode terminal 32 via the internal wiring 17, and the shielding performance of the grounding electrode 25 can be improved. In this case, since the second principal surface 202 of the first sealing member 20 can be effectively utilized as the configuration space for the grounding electrode 25, the grounding electrode 25 can be ensured to have a larger size, thereby improving the shielding performance of the grounding electrode 25. Furthermore, a grounding electrode may be provided on the first principal surface 201 of the first sealing member 20 , or may be provided on both the first principal surface 201 and the second principal surface 202 of the first sealing member 20 .

[0078] In the above embodiment, the crystal resonator piece 10 has a structure in which only one holding portion 13 is provided to connect the vibrating portion 11 and the outer frame portion 12, and the cutout portion 10 a is continuously formed to surround the outer periphery of the vibrating portion 11. However, the structure of the crystal resonator piece 10 can be modified in various ways as long as the cutout portion 10 a is provided between the vibrating portion 11 and the outer frame portion 12. For example, the crystal resonator piece 10 can be configured to include two or more holding portions 13 connecting the vibrating portion 11 and the outer frame portion 12. Alternatively, the holding portion 13 can be configured to extend from outside the corners of the vibrating portion 11 toward the outer frame portion 12.

[0079] The internal wiring 17 for ground connection may also be provided in the region along the short side of the outer frame portion 12 of the crystal resonator plate 10. For example, Figure 10 、 Figure 11 As shown, a notch 17a is formed at the end portion on the +Z' side of the Z' end surface (the end surface parallel to the Z' axis direction) of the inner wall surface 12h of the outer frame portion 12, and an internal wiring 17 for ground connection is formed on the inner wall surface of the notch 17a. Specifically, as shown in FIG. Figure 10 、 Figure 11As shown, the inner wall surface 12h of the outer frame portion 12 of the crystal vibrator plate 10 is constructed to be rectangular and annular when viewed from above, and a notch portion 17a is formed at a corner of the inner wall surface 12h when viewed from above, which is sunken into the side of the outer frame portion 12. The notch portion 17a is constructed to be approximately rectangular when viewed from above, and is provided on the inner wall surface parallel to the X-axis direction and on the +Z′ direction side of the inner wall surface 12h of the outer frame portion 12. The notch portion 17a is constructed to be sunken into the side of the outer frame portion 12. In other words, the space of the notch portion 17a is constructed to protrude outward toward the side of the outer frame portion 12. The notch portion 17a is provided to be connected to the cutout portion 10a of the above-mentioned crystal vibrator plate 10. In this way, the internal wiring 17 is formed on the inner wall surface of the outer frame portion 12 facing a third area A3 (refer to Figure 4 etc.)

[0080] Here, the second inner wall portion 17c (the wall portion on the +Z′ direction side and the wall portion on the +X direction side) of the notch 17a does not form a straight line with the inner wall surface 12h (the inner wall surface on the +Z′ direction side) of the outer frame 12. The second inner wall portion 17c is not formed along the X-end surface (the end surface parallel to the X-axis direction) of the inner wall surface 12h of the outer frame 12. Consequently, the inner wall surface 12h of the outer frame 12 has no corners protruding toward the -Z′ direction or the +X direction on the second principal surface 102 side (the side facing the -Y′ direction), thus preventing the formation of etching marks caused by these corners.

[0081] Internal wiring 17 is formed on the second inner wall portion 17c, extending from a first vibration plate-side bonding pattern 121 formed on the first principal surface 101 side of the outer frame portion 12 to the second principal surface 102 side. Internal wiring 17 connects the first vibration plate-side bonding pattern 121 formed on the first principal surface 101 side of the outer frame portion 12 to the second vibration plate-side bonding pattern 122 formed on the second principal surface 102 side of the outer frame portion 12. Although not shown, similarly to the above-described embodiment, an inclined surface is formed on the second inner wall portion 17c, forming an obtuse angle with the second principal surface 102 of the outer frame portion 12. Internal wiring 17 is formed on this inclined surface.

[0082] Figure 10 、 Figure 11 In the example, in addition to the internal wiring 17 for ground connection, a notch 18 is formed at the end of the Z' end face of the inner wall surface 12h of the outer frame portion 12 on the -Z' direction side, and an internal wiring 19 is formed on the inner wall surface of the notch 18. The notch 18 has a structure substantially the same as the notch 17a described above, and is formed to be approximately rectangular when viewed from above. It is provided on the inner wall surface of the inner wall surface 12h of the outer frame portion 12, which is parallel to the X-axis direction and on the -Z' direction side. The internal wiring 19 is formed on the inner wall surface of the outer frame portion 12, which faces the second area A2 (see FIG. 1 ). Figure 4The notch 18 is formed so as to be recessed into the outer frame 12 and is provided to connect to the cutout 10a of the crystal resonator plate 10. Furthermore, the connection bonding pattern 12a is connected to the connection bonding pattern 12e formed on the second principal surface 102 side of the outer frame 12 via internal wiring 19 provided in the notch 18 formed on the inner wall surface 12h of the outer frame 12.

[0083] Figure 10 、 Figure 11 In the example shown, by forming the inner wall surfaces of the cutouts 17a and 18 as inclined surfaces, a structure is achieved that reduces the risk of disconnection of the internal wiring 17 and 19. Furthermore, since the cutouts 17a and 18 are formed so as to be recessed into the outer frame 12, the effective area of ​​the vibrating portion 11 can be ensured, thereby achieving a compact crystal resonator piece 10 with stable electrical characteristics. Furthermore, while the cutouts 17a and 18 are formed to be approximately rectangular in plan view, this is not limiting. The shapes of the cutouts 17a and 18 may also be V-shaped, trapezoidal, arcuate, or elliptical, for example.

[0084] In the above embodiment, an AT-cut crystal resonator plate is used as the crystal resonator plate 10 , but other crystal resonator plates (eg, an SC-cut crystal resonator plate, a Z-cut crystal plate, etc.) may be used.

[0085] In the above embodiment, the number of external electrode terminals 32 on the second principal surface 302 of the second sealing member 30 is four, but this is not limiting. The number of external electrode terminals 32 may also be, for example, two, six, or eight. Furthermore, while the present invention has been described as being applied to the crystal resonator 100, this is not limiting. For example, the present invention may also be applied to a piezoelectric oscillator, such as a crystal oscillator. In the case of a crystal oscillator, a structure may be employed in which the internal wiring 17 is connected to a wiring electrode connected to an IC mounted on the crystal resonator.

[0086] In the above embodiment, the first sealing member 20 and the second sealing member 30 are formed of crystal sheets, but the present invention is not limited thereto. The first sealing member 20 and the second sealing member 30 may be formed of, for example, glass or resin.

[0087] In addition, in the above embodiment, an example of applying the present invention to a piezoelectric vibration device with a three-layer structure in which a crystal vibration piece is sandwiched between a first sealing member and a second sealing member is described, but the present invention is not limited to this. The present invention can also be applied to a piezoelectric vibration device with a structure in which a crystal vibration piece is mounted inside a base made of ceramic or the like.

[0088] This application claims priority based on Japanese Patent Application No. 2023-032554 filed in Japan on March 3, 2023. It goes without saying that all the contents are incorporated into this application.

Claims

1. A piezoelectric vibrating piece having a rectangular shape and comprising a first excitation electrode formed on one principal surface of a substrate and a second excitation electrode formed on the other principal surface of the substrate, forming a pair with the first excitation electrode, wherein: A rectangular vibrating portion, an outer frame portion surrounding the outer periphery of the vibrating portion, and a holding portion connecting a portion of the vibrating portion and a portion of the outer frame portion, wherein a cutout portion formed by cutting out the substrate is provided between the vibrating portion and the outer frame portion. The electrodes formed on one main surface of the substrate are electrically connected to the electrodes formed on the other main surface of the substrate via internal wiring formed on the inner wall surface of the outer frame. In the space of the cut-out portion, if the area sandwiched between the inner wall surface of the outer frame portion and the outer wall surface of the vibrating portion is taken as the first area; in the area remaining after removing the first area from the space of the cut-out portion, if the area sandwiched between the inner wall surface of the outer frame portion and the outer wall surface of the retaining portion is taken as the second area, and the area sandwiched between the inner wall surfaces of the outer frame portion is taken as the third area, then the internal wiring is formed at a position on the inner wall surface of the outer frame portion facing at least one of the second area and the third area.

2. The piezoelectric vibrating piece according to claim 1, wherein: The inner wall surface of the outer frame is rectangular and annular in plan view, and a notch recessed into the outer frame is formed at a corner of the inner wall surface in plan view. The internal wiring is formed on the inner wall surface of the notch.

3. A piezoelectric vibration device comprising the piezoelectric vibration piece according to claim 1 or 2, characterized in that: A first sealing member covering the first excitation electrode of the piezoelectric vibrating piece and a second sealing member covering the second excitation electrode of the piezoelectric vibrating piece are provided. The first sealing member is bonded to the piezoelectric vibrating piece, and the second sealing member is bonded to the piezoelectric vibrating piece, thereby providing an internal space for airtightly sealing the vibrating portion of the piezoelectric vibrating piece including the first excitation electrode and the second excitation electrode.

4. The piezoelectric vibration device according to claim 3, wherein: The grounding electrode formed on one of the two main surfaces of the first sealing member is electrically connected to an external electrode terminal formed on the main surface of the second sealing member that does not face the internal space via the internal wiring.

5. The piezoelectric vibration device according to claim 3, wherein: An annular sealing portion for airtightly sealing the vibration portion of the piezoelectric vibrating piece is provided between the first sealing member and the piezoelectric vibrating piece, and between the second sealing member and the piezoelectric vibrating piece, respectively. The sealing portions are electrically connected to the internal wiring.

6. The piezoelectric vibration device according to claim 3, wherein: Only one holding portion is provided, and the holding portion extends from a corner portion of the vibrating portion toward the outer frame portion.

7. The piezoelectric vibration device according to claim 3, wherein: The piezoelectric vibrating piece is an AT-cut quartz crystal vibrating piece, and the internal wiring is formed on an inner wall surface of the outer frame portion that is parallel to the Z′-axis direction of the AT-cut.

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