JP2018032944A - Crystal diaphragm, and crystal vibration device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystal diaphragm of which the reliability is further improved by suppressing deterioration of electrical characteristics while improving impact resistance, and a crystal vibration device.SOLUTION: The present invention relates to an AT-cut crystal diaphragm 2 comprising: a vibration part 22 that is rectangular in a planar view, with excitation electrodes formed on front and rear principal surfaces in a central portion; a cutout part 21 that is rectangular in a planar view, formed in an outer periphery of the vibration part; an outer frame part 23 that is rectangular in a planar view, formed in an outer periphery of the cutout part; and one connection part 24 which connects the vibration part and the outer frame part and extends in a Z' axis direction of the vibration part from one end of a side of the vibration part in an X axis direction. Projections 23b and 23c are formed in an inner peripheral end of the outer frame part in a Z' axis direction proximate to a corner of the vibration part that is diagonal to a corner of the vibration part to which the connection part is connected.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an AT-cut quartz crystal plate provided with a first excitation electrode formed on one main surface and a second excitation electrode formed on another main surface, and a crystal vibration provided with the crystal plate. Regarding devices.

  In recent years, the operating frequency of various electronic devices has been increased, and the size of packages has been reduced (especially low profile). For this reason, with the increase in the frequency and the size of the package, the crystal vibrating device is required to cope with the increase in the frequency and the size of the package.

  In particular, the quartz resonator device corresponding to the miniaturization includes a first sealing member and a second sealing member whose casing is configured by a rectangular parallelepiped package and made of a brittle material such as glass or quartz. A quartz crystal plate having an excitation electrode formed on a surface thereof, the first sealing member and the second sealing member being laminated and bonded via the quartz plate, and disposed inside the package Some of the plate excitation electrodes are hermetically sealed (see, for example, Patent Document 1 below). Such a laminated crystal vibration device is generally called a sandwich structure.

Japanese Patent Laying-Open No. 2015-122652

  By the way, in the quartz resonator device having the sandwich structure as described above, a vibration region for exciting as a crystal resonator, a crystal resonator plate, and a sealing member are bonded to the functional region of the crystal resonator plate to vibrate. A region as an outer frame part for hermetically sealing the part, and a region as a cutout part for isolating the outer frame part and the vibration part so that the excitation of the vibration part is not hindered by the outer frame part , A region as a connecting portion for connecting the vibrating portion and the outer frame portion, and a wiring portion for electrically connecting the wiring of the crystal diaphragm and the wiring of the sealing member (a wiring pattern or a through hole for wiring) Etc.).

  In such a crystal oscillating device, depending on the structure of the connecting part, if the transmission of vibration displacement from the vibrating part to the outer frame part becomes large, vibration leakage may occur and the piezoelectric vibration efficiency may deteriorate, or external vibration such as dropping may occur. There has been a problem that the connecting part is damaged due to the vibration part being greatly bent with respect to the impact. In particular, it is difficult for a quartz crystal vibration device having a sandwich structure to simultaneously eliminate the adverse effects of vibration leakage and improve the impact resistance performance only by designing the connecting portion.

  Accordingly, in order to solve the above-described problems, an object of the present invention is to provide a quartz diaphragm and a quartz vibrating device with higher reliability that suppresses deterioration of electrical characteristics while improving impact resistance.

  In order to achieve the above object, the present invention is an AT-cut quartz crystal vibrating plate having a rectangular shape in plan view having one main surface and another main surface, and is formed on one main surface at a central portion of the crystal vibrating plate. Formed on the outer periphery of the cutout portion formed on the outer periphery of the vibration portion, the cutout portion formed on the outer periphery of the rectangular portion in plan view in which the first excitation electrode is formed and the second excitation electrode is formed on the other main surface In addition, the outer peripheral portion whose inner peripheral end is rectangular in plan view, the vibrating portion and the outer frame portion are connected to each other, and from one end portion of the side along the X-axis direction of the vibrating portion, Z ′ of the vibrating portion And an outer frame portion that is close to a corner portion of the diagonal vibration portion with respect to a corner portion of the vibration portion to which the connection portion is connected. A convex portion is formed at the inner peripheral end in the Z′-axis direction.

  With the above configuration, the connection between the vibration part and the outer frame part is realized by only one connecting part extending from one end of the side along the X-axis direction of the vibration part along the Z′-axis direction of the vibration part. By doing so, the connecting portion extending along the X-axis, which is the axial direction of the vibration displacement distribution of the AT-cut vibrating portion, is not configured. In addition, the vibration portion having a rectangular shape in plan view is a region where the vibration displacement at the corner portion (the end portion of the side in the X-axis direction) is the lowest. For this reason, the influence of vibration leakage from the vibration part to the outer frame part is reduced, and the vibration part of the crystal diaphragm can be piezoelectrically vibrated more efficiently. In addition, by connecting the vibrating part and the outer frame part with only one connecting part, the degree of stress applied to the vibrating part is reduced compared to the case where the vibrating part and the outer frame part are connected by a plurality of connecting parts. it can. For this reason, the stress applied from the outer frame part suppresses the frequency shift caused by the stress applied to the vibration part, and therefore the vibration part of the crystal diaphragm can be more stably piezoelectrically vibrated.

  Also, when an external impact is applied to the quartz plate due to dropping or processing, the quartz plate is most likely to be displaced with respect to the corner of the vibrating portion to which the connecting portion is connected. It becomes the free end of the vibration part which is a corner | angular part of the vibration part of an angular position. Since the connecting portion extends along the Z′-axis direction, the free end of the vibrating portion is excessively displaced in the X-axis direction, particularly in the plate surface direction (X-axis and Z′-axis). Cheap. Therefore, a convex portion is formed on the inner peripheral end in the Z′-axis direction of the outer frame portion adjacent to the corner portion of the diagonal vibration portion with respect to the corner portion of the vibration portion to which the coupling portion is connected. Therefore, before the free end of the vibrating part is excessively displaced in the X-axis direction, the end part near the free end of the vibrating part comes into contact with and supports the convex part of the inner peripheral end of the outer frame part in the Z′-axis direction. Is done. For this reason, the vibration part of the crystal diaphragm does not bend greatly in the plate surface direction, and breakage of the connecting part can be prevented. In addition, since the convex portion is formed in the outer frame portion without forming the convex portion in the vibration portion, the piezoelectric vibration characteristics such as the change of the vibration displacement region and the occurrence of spurious due to the formation of the convex portion in the vibration portion. The risk of adverse effects is eliminated, and the impact resistance can be improved by increasing the rigidity of the outer frame.

  In addition, by providing a convex portion only at a part of the inner peripheral end of the outer frame portion in the Z′-axis direction, the effective area of the vibrating portion is not reduced, and the electric power generated by the reduction of the vibration region due to the miniaturization of the crystal diaphragm is eliminated. It is possible to eliminate the deterioration of the mechanical characteristics.

  In addition, by forming a convex portion that narrows the width of the cutout portion at the inner peripheral end in the Z′-axis direction of the outer frame portion that is close to the other corner of the vibrating portion to which the connecting portion is not connected, More than two points can be used, and displacement in the plate surface direction (X axis and Z ′ axis) of the vibration part can be further suppressed.

  As described above, according to the present invention, it is possible to provide a more reliable quartz crystal diaphragm that has improved impact resistance and suppressed deterioration of electrical characteristics.

  In the present invention, the quartz crystal vibration having a sandwich structure in which the first sealing member that covers one main surface of the crystal diaphragm and the second sealing member that covers the other main surface of the crystal diaphragm is provided. Desirable to apply to devices.

  According to such a configuration, since the crystal diaphragm is sandwiched between the first sealing member and the second sealing member, a relatively small crystal vibration device can be obtained. Further, since the above-described quartz diaphragm is provided, it is possible to suppress the deterioration of the electrical characteristics while improving the impact resistance while realizing the miniaturization as the hydroelectric vibration device.

  As described above, according to the present invention, it is possible to provide a more reliable quartz crystal diaphragm that has improved impact resistance and suppressed deterioration of electrical characteristics.

FIG. 1 is a schematic configuration diagram showing each configuration of a crystal resonator according to an embodiment of the present invention. FIG. 2 is a schematic plan view of the first sealing member of the crystal resonator. FIG. 3 is a schematic back view of the first sealing member of the crystal resonator. FIG. 4 is a schematic plan view of a crystal diaphragm of a crystal resonator. FIG. 5 is a schematic back view of the crystal diaphragm of the crystal resonator. FIG. 6 is a schematic plan view of the second sealing member of the crystal resonator. FIG. 7 is a schematic back view of the second sealing member of the crystal resonator. FIG. 8 is a plan view relating to another embodiment of the present invention. FIG. 9 is a cross-sectional view taken along the line CC of FIG. FIG. 10 is a plan view relating to another embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, a case where the present invention is applied to a crystal resonator as a crystal resonator device will be described.

  In the crystal resonator 101 according to the present embodiment, as shown in FIG. 1, the crystal vibrating plate 2 and the first excitation electrode 221 (see FIG. 4) of the crystal vibrating plate 2 are covered, and one main surface 211 of the crystal vibrating plate 2. A first sealing member 3 that hermetically seals the first excitation electrode 221 formed on the first excitation electrode 221 and a second excitation electrode 222 (see FIG. 5) of the crystal diaphragm 2 on the other main surface 212 of the crystal diaphragm 2. A second sealing member 4 that covers and seals the second excitation electrode 222 formed in a pair with the first excitation electrode 221 is provided. In the crystal resonator 101, the crystal diaphragm 2 and the first sealing member 3 are joined, and the crystal diaphragm 2 and the second sealing member 4 are joined to form a sandwich-structured package 12.

  And the 1st sealing member 3 and the 2nd sealing member 4 are joined via the crystal diaphragm 2, and the internal space 13 of the package 12 is formed, In this internal space 13 of this package 12, crystal | crystallization The vibration part 22 including the first excitation electrode 221 and the second excitation electrode 222 formed on both main surfaces 211 and 212 of the diaphragm 2 is hermetically sealed. The crystal resonator 101 according to this embodiment has a package size of, for example, 1.0 × 0.8 mm, and is intended to be downsized and low-profile. Further, with the miniaturization, the package 12 uses the through holes (first to third through holes) to conduct the electrodes without forming a castellation.

  Next, each configuration of the above-described crystal resonator 101 will be described with reference to FIGS. Here, each member configured as a single unit in which the crystal diaphragm 2, the first sealing member 3, and the second sealing member 4 are not joined will be described.

  As shown in FIGS. 4 and 5, the quartz diaphragm 2 is made of quartz as a piezoelectric material, and both main surfaces (one main surface 211 and the other main surface 212) are formed as flat smooth surfaces (mirror finish). Yes. These one main surface 211 and the other main surface 212 are parallel surfaces. In this embodiment, an AT-cut quartz plate that performs rectangular thickness-shear vibration in a plan view is used as the quartz plate 2. In the crystal diaphragm 2 shown in FIGS. 4 and 5, both main surfaces 211 and 212 of the crystal diaphragm 2 are XZ ′ planes. In this XZ ′ plane, the direction parallel to the short direction (short side direction) of the crystal diaphragm 2 is the X axis direction, and the direction parallel to the long direction (long side direction) of the crystal diaphragm 2 is the Z ′ axis. It is considered to be a direction. The AT cut is an angle of 35 ° around the X axis with respect to the Z axis among the electric axis (X axis), the mechanical axis (Y axis), and the optical axis (Z axis), which are the three crystal axes of artificial quartz. This is a processing method of cutting at an angle inclined by 15 '. In an AT cut quartz plate, the X axis coincides with the crystal axis of the quartz crystal. The Y′-axis and the Z′-axis coincide with the axes inclined by 35 ° 15 ′ from the Y-axis and the Z-axis of the crystal axis of the quartz crystal, respectively. The Y′-axis direction and the Z′-axis direction correspond to the cutting direction when cutting the AT-cut quartz plate.

  The center portion of the quartz crystal plate 2 has a vibrating portion 22 formed in a rectangular shape in plan view, and a pair of excitation electrodes (first excitation surface) on both main surfaces (one main surface 211 and another main surface 212). An electrode 221 and a second excitation electrode 222) are formed. The first excitation electrode 221 and the second excitation electrode 222 include extraction electrodes (first extraction electrode 223 and second extraction electrode) for connection to external electrode terminals (one external electrode terminal 431 and another external electrode terminal 432) described later. 224) is connected.

That is, the first excitation electrode 221 is formed on one main surface side of the vibration part 22, the second excitation electrode 222 is formed on the other main surface side of the vibration part 22 while facing the first excitation electrode 221.
Further, the first excitation electrode 221 is formed with a first extraction electrode 223 that extends to the outer frame portion 23 via a connecting portion 24 described later and is finally connected to one external electrode terminal 431. The second excitation electrode 222 is formed with a second extraction electrode 224 that extends to the outer frame portion 23 via a connecting portion 24 described later and is finally connected to the other external electrode terminal 432.

  In addition, the outer peripheral end and the inner peripheral end that are formed on the outer periphery of the vibrating portion 22 of the crystal vibrating plate 2 and penetrate in the thickness direction of the crystal vibrating plate 2 (through between one main surface 211 and the other main surface 212) are flat. The cutout portion 21 having a rectangular shape in view, the outer peripheral end formed in a state of surrounding the outer periphery of the vibration portion 22 and the cutout portion 21, and the outer frame portion 23 having a rectangular shape in plan view, and the vibration portion 22. It has one connecting portion (holding portion) 24 that connects the outer frame portion 23 and extends in the Z′-axis direction of the crystal vibrating plate 2, and the crystal vibrating plate 2 has the vibrating portion 22 and the connecting portion 24. And the outer frame portion 23 are integrally provided. Both main surfaces (one main surface and the other main surface) of the vibrating portion 22, the connecting portion 24, and the outer frame portion 23 are formed as the same surfaces or parallel surfaces having different thicknesses. In this embodiment, since the vibration part 22 and the connection part 24 have the same thickness and the outer frame part 23 is thicker than these thicknesses, both main surfaces of the vibration part 22 and the connection part 24 (one The main surface and the other main surface are the same surface, and both main surfaces (one main surface, one main surface, and other main surfaces) of the vibrating portion 22 and the connecting portion 24 with respect to both main surfaces (one main surface and other main surfaces). The other principal surface is a parallel surface.

  In addition, the thickness of the vibration part 22 and the connection part 24 may be changed without being limited to the present embodiment. For example, the outer frame part 23 is formed to be the thickest and the vibration part 22 is formed to be the next thickest. You may form so that the part 24 may become the thinnest. Alternatively, a region having a different thickness may be formed in a part of the vibrating portion 22 to have a mesa shape or an inverted mesa shape. Due to the difference in thickness between the outer frame portion 23 and the connecting portion 24, the natural frequency of the piezoelectric vibration between the outer frame portion 23 and the connecting portion 24 or between the connecting portion 24 and the vibrating portion 22 is different. It becomes difficult to resonate.

  As shown in FIGS. 8 and 9, the connecting portion 24 and the outer frame portion 23 may have the same thickness, and only the vibrating portion 22 may be formed thin. In such a configuration, the natural frequencies of the piezoelectric vibrations of the vibration part 22 and the connection part 24 are different, and the connection part 24 is less likely to resonate with the piezoelectric vibration of the vibration part 22. The rigidity of the connection portion with the outer frame portion 23 can be increased, and the concentration of strain stress applied to the connecting portion 24 can be reduced by the vibration portion 22 being displaced by an external impact.

  That is, in this embodiment, the connecting portion 24 is provided at only one position in the Z′-axis direction between the vibrating portion 22 and the outer frame portion 23, and is positioned in the + X direction and the −Z ′ direction of the vibrating portion 22. Extends from only one corner portion 22a (one end portion of the side of the vibrating portion 22 along the X-axis direction) to the outer frame portion 23 in the -Z 'direction (extends along the Z'-axis direction) Have been). A portion where the connecting portion 24 is not provided is a space (gap) as the cutout portion 21. As described above, the Z′-axis is provided only at one position of the corner portion 22a where the displacement of the piezoelectric vibration is relatively small (one end portion of the side along the X-axis direction of the vibration portion 22) in the outer peripheral end portion of the vibration portion 22. One connecting portion 24 extending in the direction is provided.

  For this reason, the connection part 24 extended along the X-axis which is an axial direction with higher vibration displacement distribution among the vibration parts 22 of AT cut is not comprised. In addition, in the vibration part 22 having a rectangular shape in plan view, the vibration displacement at the corner (the end of the side in the X-axis direction) is the lowest region. For this reason, the influence of the leakage of the piezoelectric vibration from the vibration part 22 to the outer frame part 23 via the connecting part 24 is reduced, and the vibration part 22 of the crystal diaphragm 2 can be more efficiently piezoelectrically vibrated. Further, compared to the case where two or more connecting portions 24 are provided, the stress acting on the vibration portion 22 can be reduced, and the frequency shift of the piezoelectric vibration caused by such stress can be reduced to stabilize the piezoelectric vibration. Can be improved. Moreover, it can be set as the crystal diaphragm 2 with the outer frame part advantageous for size reduction.

  As described above, the present invention is characterized by having only one connecting portion 24 extending along the Z′-axis direction from the end portion of the vibrating portion 22 in the X-axis direction. In addition, at the inner circumferential end of the outer frame portion 23 in the Z′-axis direction, a convex portion that is close to the corner portion of the diagonal portion (free end of the vibrating portion) with respect to the corner portion of the vibrating portion 22 to which at least the connecting portion is connected It is also characterized by forming. Hereinafter, as shown in FIGS. 4 and 5, details of additional feature points according to the present embodiment will be described.

  A semicircular convex portion 23c adjacent to the corner portion 22c at the diagonal position of the corner portion 22a of the vibration portion 22 to which the connecting portion 24 is connected is formed on the inner peripheral end 231 of the outer frame portion 23 in the Z′-axis direction. The same shape is formed at the inner peripheral end 232 facing the inner peripheral end 231 of the outer frame portion 23 in the X-axis direction, close to the corner portion 22b of the vibrating portion 22 and facing the convex portion 23c. The convex portion 23b is formed. That is, the two inner peripheral ends 231 and 232 in the Z′-axis direction of the outer frame portion 23 have two semicircular convex portions 23b that are close to the corner portions 22c and 22b of the vibration portion 22. And the convex portion 23 c are formed symmetrically with respect to the center line along the Z ′ axis while passing through the center of the outer frame portion 23 in the X-axis direction.

  For this reason, before the corner | angular part 22c which is a free end of the vibration part 22 arises an excessive displacement in the X-axis direction, the convex part 23c of the inner peripheral end 231 of the outer frame part 23 in the Z′-axis direction The end near the corner 22c abuts and is supported, and the end near the corner 22d of the vibrating portion 22 abuts and is supported by the convex 23d of the inner peripheral end 232 of the outer frame 23 in the Z′-axis direction. The For this reason, the vibration part 22 of the crystal diaphragm 2 does not bend greatly in the plate surface direction, and damage to the connecting part 24 can be prevented. In addition, since the convex portions 23c and 23d are provided only at a part of the inner peripheral end of the outer frame portion 23 in the Z′-axis direction, the effective area of the vibration portion 22 is not reduced, and the crystal vibration is prevented. It is possible to eliminate the deterioration of the electrical characteristics due to the reduction of the vibration region due to the downsizing of the plate 2.

  In addition, the number of convex parts is not limited to the present embodiment, and as shown in FIG. 10A, the number of convex parts is outside the corner part 22 c that is a diagonal position of the corner part 22 a of the vibration part 22 to which the connecting part 24 is connected. A semicircular convex portion 23c may be formed at only one place on the inner peripheral end 231 of the frame portion 23 in the Z′-axis direction. Further, as shown in FIG. 10B, the Z′-axis direction of the outer frame portion 23 adjacent to all the corner portions 22b, 22c, and 22d other than the corner portion 22a of the vibration portion 22 to which the connecting portion 24 is connected. A semicircular convex portion 23b, a convex portion 23c, and a convex portion 23d may be formed at three locations of the inner peripheral end 231 and the inner peripheral end 232.

  Note that the convex portion is not limited to a semicircular shape in plan view, and may be a curved shape such as an elliptical shape or a polygonal shape such as a triangle or a rectangle. . In addition, the thickness of each convex portion is desirably the same as the thickness of the outer frame portion 23, the vibration portion 22 and the like when formed in accordance with the processing step, but is not particularly limited.

  In the present invention, in addition to the above-described features, in particular, in addition to having only one connecting portion 24 extending along the Z′-axis direction from the end portion of the vibrating portion 22 in the X-axis direction, The connecting portion 24 is also characterized in that a wide portion that gradually increases in width toward the outer frame portion 23 is formed. Hereinafter, as shown in FIGS. 4 and 5, details of additional feature points according to the present embodiment will be described.

  In the connecting portion 24 of this embodiment, a wide portion 24 a and a wide portion 24 b are formed on both the −X-axis side surface and the + X-axis side surface of the connecting portion. Each wide portion is formed in a substantially square shape in a plan view that is linearly wide only in one direction from the end portion 241 in contact with the vibration portion 22 to the entire end portion 242 in contact with the outer frame portion 23.

  For this reason, the rigidity of the connecting portion with the outer frame portion 23 on the fixed end side of the connecting portion 24 is increased, and the strain stress applied to the connecting portion 24 due to the displacement of the vibrating portion 22 of the crystal diaphragm 2 due to an external impact. Can be dispersed so as to spread in the outer frame portion. In addition, as described above, the influence of vibration leakage from the vibrating portion 22 to the outer frame portion 23 can be suppressed as compared with the case where the entire connecting portion 24 is configured to be wide.

  Note that the shape of these wide portions is not limited to this embodiment, and as shown in FIG. 10A, the wide portion 24a1 is connected to the end point 241 contacting the vibrating portion 22 from the center of the connecting portion 24 and the outer frame. 23 may be formed so as to be wide in a curved shape in two directions of a connection point with an end portion 242 in contact with 23. Further, as shown in FIG. 10B, the wide portion 24 a 2 has two directions, that is, a connection point between the center of the connecting portion 24 and the end portion 241 in contact with the vibration portion 22 and a connection point between the end portion 242 in contact with the outer frame 23. It may be formed so as to be wide in a straight line. As described above, the wide portion of this embodiment may be formed on the entire connecting portion 24 (the entire connecting point 242 with the outer frame portion 23 from the connecting point 241 with the vibrating portion 22) or only on a part thereof. May be. Moreover, the wide part may be formed not only on the outer frame part side but on both the outer frame part side and the vibrating part side. Further, the shape thereof may be a curved shape, a linear shape, or a combination thereof.

  The first extraction electrode 223 is extracted from the first excitation electrode 221, and is connected to the connection joint pattern 27 formed on the outer frame portion 23 via the connection portion 24. The second extraction electrode 224 is extracted from the second excitation electrode 222 and connected to the connection joint pattern 28 formed on the outer frame portion 23 via the connection portion 24.

  The first excitation electrode 221 is a base PVD film formed by physical vapor deposition on one main surface 2201 of the vibration part 22 and an electrode formed by stacking the base PVD film by physical vapor deposition. It consists of a PVD film. The first extraction electrode 223 includes a base PVD film formed by physical vapor deposition on a part of one main surface 2401 and a part of one side surface of the connecting portion 24, and a physical layer on the base PVD film. The electrode PVD film is formed by vapor deposition. The second excitation electrode 222 is a base PVD film formed by physical vapor deposition on the other main surface 2202 of the vibration part 22 and an electrode formed by stacking the base PVD film by physical vapor deposition. It consists of a PVD film. The second extraction electrode 224 includes a base PVD film formed by physical vapor deposition on a part of the other main surface 2402 and a part of the other side surface of the connecting portion 24, and a physical layer on the base PVD film. The electrode PVD film is formed by vapor deposition.

  On both main surfaces 211 and 212 of the crystal diaphragm 2, vibration side sealing portions 25 for joining the crystal diaphragm 2 to the first sealing member 3 and the second sealing member 4 are provided. A vibration side first bonding pattern 251 for bonding to the first sealing member 3 is formed on the vibration side sealing portion 25 of the one main surface 211 of the crystal diaphragm 2. A vibration-side second bonding pattern 252 for bonding to the second sealing member 4 is formed on the vibration-side sealing portion 25 of the other main surface 212 of the crystal diaphragm 2. The vibration side first bonding pattern 251 and the vibration side second bonding pattern 252 are provided on the outer frame portion 23 described above, and are formed in an annular shape in plan view. The vibration side first bonding pattern 251 and the vibration side second bonding pattern 252 are provided so as to be close to the outer peripheral edges of both the main surfaces 211 and 212 of the quartz crystal vibrating plate 2. The pair of first excitation electrode 221 and second excitation electrode 222 of the crystal diaphragm 2 are not electrically connected to the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252.

  The vibration-side first bonding pattern 251 includes a base PVD film 2511 formed by physical vapor deposition on one main surface 211 and an electrode PVD formed by physical vapor deposition on the base PVD film 2511 and stacked. A film 2512. The vibration-side second bonding pattern 252 includes a base PVD film 2521 formed by physical vapor deposition on the other main surface 212 and an electrode PVD formed by physical vapor deposition on the base PVD film 2521 and stacked. A film 2522. That is, the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252 have the same configuration, and a plurality of layers are stacked on the vibration side sealing portion 25 of both main surfaces 211 and 212, A Ti layer (or Cr layer) and an Au layer are formed by vapor deposition from the lowermost layer side. Thus, in the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252, the underlying PVD films 2511 and 2521 are made of a single material (Ti (or Cr)), and the electrode PVD films 2512 and 2522 are formed. The electrode PVD films 2512 and 2522 are made of a single material (Au) and are thicker than the underlying PVD films 2511 and 2521. Further, the first excitation electrode 221 and the vibration-side first bonding pattern 251 formed on the one main surface 211 of the crystal diaphragm 2 have the same thickness, and the first excitation electrode 221 and the vibration-side first bonding pattern 251 have the same thickness. The second excitation electrode 222 and the vibration side second bonding pattern 252 formed on the other main surface 212 of the quartz crystal plate 2 have the same thickness, and the second excitation electrode 222 and the vibration side are made of the same metal. The surface of the second bonding pattern 252 is made of the same metal. The vibration side first bonding pattern 251 and the vibration side second bonding pattern 252 are non-Sn patterns.

  Here, the first excitation electrode 221, the first extraction electrode 223, and the vibration-side first bonding pattern 251 can have the same configuration, and in this case, the first excitation electrode 221 and the first extraction electrode 223 are the same process. And the vibration side 1st joining pattern 251 can be formed in a lump. Similarly, the second excitation electrode 222, the second extraction electrode 224, and the vibration-side second bonding pattern 252 can have the same configuration. In this case, the second excitation electrode 222, the second extraction electrode 224 are performed in the same process. And the vibration side 2nd joining pattern 252 can be formed collectively. Specifically, the underlying PVD film or the electrode PVD film is formed by a PVD method such as vacuum deposition, sputtering, ion plating, MBE, or laser ablation (for example, a film forming method for patterning in processing such as photolithography). Thus, the film formation can be performed at one time, the number of manufacturing steps can be reduced, and the cost can be reduced.

  In addition, as shown in FIGS. 4 and 5, the crystal diaphragm 2 is formed with one through hole (first through hole 26) penetrating between the one main surface 211 and the other main surface 212. The first through hole 26 is provided in the outer frame portion 23 of the crystal diaphragm 2. The 1st through-hole 26 is connected with the joining pattern 453 for a connection of the 2nd sealing member 4 mentioned later.

  As shown in FIGS. 1, 4, and 5, the first through hole 26 has a through electrode 261 for conducting the electrodes formed on the one main surface 211 and the other main surface 212. It is formed along the inner wall surface. The central portion of the first through hole 26 becomes a hollow through portion 262 that penetrates between the one main surface 211 and the other main surface 212. Connection joint patterns 264 and 265 are formed on the outer periphery of the first through hole 26. The connection bonding patterns 264 and 265 are provided on both main surfaces 211 and 212 of the crystal diaphragm 2.

  The connection pattern 264 for connection of the first through hole 26 formed on the one main surface 211 of the crystal diaphragm 2 extends along the X-axis direction in the outer frame portion 23. In addition, a connection bonding pattern 27 connected to the first extraction electrode 223 is formed on one main surface 211 of the crystal diaphragm 2, and this connection bonding pattern 27 is also formed in the X direction in the outer frame portion 23. Extending along. The connecting joint pattern 27 is provided on the opposite side of the connecting joint pattern 264 with respect to the Z′-axis direction, with the vibrating portion 22 (first excitation electrode 221) interposed therebetween. That is, the connecting joint patterns 27 and 264 are provided on both sides of the vibrating portion 22 in the Z′-axis direction.

  Similarly, the connection pattern 265 for connection of the first through hole 26 formed on the other main surface 212 of the crystal diaphragm 2 extends along the X-axis direction in the outer frame portion 23. In addition, a connection bonding pattern 28 connected to the second extraction electrode 224 is formed on the other main surface 212 of the crystal diaphragm 2, and this connection bonding pattern 28 is also formed in the outer frame portion 23 in the X-axis direction. Extending along. The connecting joint pattern 28 is provided on the opposite side of the connecting joint pattern 265 with respect to the Z ′ direction with the vibrating portion 22 (second excitation electrode 222) interposed therebetween. That is, the connecting joint patterns 28 and 265 are provided on both sides in the Z ′ direction of the vibrating portion 22.

  The connection bonding patterns 27, 28, 264, and 265 have the same configuration as the vibration-side first bonding pattern 251 and the vibration-side second bonding pattern 252, and the vibration-side first bonding pattern 251 and the vibration-side second bonding pattern 252 are the same. Can be formed by the same process. Specifically, the connection bonding patterns 27, 28, 264, and 265 are formed of a base PVD film formed by physical vapor deposition on both main surfaces 211 and 212 of the crystal diaphragm 2, and the base PVD film. It consists of an electrode PVD film formed by physical vapor deposition thereon.

  In the crystal unit 101, the first through hole 26 and the connecting bonding patterns 27, 28, 264, 265 are formed inside the inner space 13 (inside the inner peripheral surface of the bonding material 11) in plan view. The internal space 13 is formed inward (inner side) of the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252 in plan view. The inside of the internal space 13 means strictly the inside of the inner peripheral surface of the bonding material 11 without including the bonding material 11 described later. The first through hole 26 and the connecting bonding patterns 27, 28, 264, 265 are not electrically connected to the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252.

The first sealing member 3 is made of a material having a bending rigidity (secondary moment of section × Young's modulus) of 1000 [N · mm ² ] or less. Specifically, as shown in FIGS. 2 and 3, the first sealing member 3 is a rectangular parallelepiped substrate formed from a single glass wafer, and the other main surface 312 ( The surface to be bonded to the quartz diaphragm 2 is formed as a flat smooth surface (mirror finish).

  The other main surface 312 of the first sealing member 3 is provided with a sealing-side first sealing portion 32 for joining to the crystal diaphragm 2. The sealing side first sealing portion 32 is formed with a sealing side first bonding pattern 321 for bonding to the crystal vibrating plate 2. The sealing side first bonding pattern 321 is formed in an annular shape in plan view. The sealing-side first bonding pattern 321 is provided so as to be close to the outer peripheral edge of the other main surface 312 of the first sealing member 3. The sealing side first bonding pattern 321 has the same width at all positions on the sealing side first sealing portion 32 of the first sealing member 3.

  The sealing-side first bonding pattern 321 is formed by stacking a base PVD film 3211 formed by physical vapor deposition on the first sealing member 3 and a physical vapor deposition on the base PVD film 3211. Electrode PVD film 3212 formed. Note that in this embodiment, Ti (or Cr) is used for the base PVD film 3211 and Au is used for the electrode PVD film 3212. Moreover, the sealing side 1st joining pattern 321 is a non-Sn pattern. Specifically, the sealing side first bonding pattern 321 is configured by laminating a plurality of layers on the sealing side first sealing portion 32 of the other main surface 312, and the Ti layer (or from the lowermost layer side). Cr layer) and Au layer are formed by vapor deposition.

  On the other main surface 312 of the first sealing member 3, that is, on the surface facing the crystal diaphragm 2, connection joint patterns 35 and 36 to be joined to the connection joint patterns 264 and 27 of the crystal diaphragm 2 are formed. Has been. The connecting bonding patterns 35 and 36 extend along the direction in the short side direction (A1 direction in FIG. 3) of the first sealing member 3. The connecting bonding patterns 35 and 36 are provided at a predetermined interval in the long side direction (A2 direction in FIG. 3) of the first sealing member 3, and the connecting bonding patterns 35 and 36 are spaced in the A2 direction. Is substantially the same as the interval (see FIG. 4) in the Z′-axis direction of the connection pattern 264, 27 for connection of the crystal plate 2. The connection bonding patterns 35 and 36 are connected to each other through the wiring pattern 33. The wiring pattern 33 is provided between the connection bonding patterns 35 and 36. The wiring pattern 33 extends along the A2 direction. The wiring pattern 33 is not bonded to the connection bonding patterns 264 and 27 of the crystal diaphragm 2.

  The connection bonding patterns 35 and 36 and the wiring pattern 33 have the same configuration as the sealing-side first bonding pattern 321, and can be formed by the same process as the sealing-side first bonding pattern 321. Specifically, the connecting bonding patterns 35 and 36 and the wiring pattern 33 include a base PVD film formed by physical vapor deposition on the other main surface 312 of the first sealing member 3, and the base PVD film. It consists of an electrode PVD film formed by physical vapor deposition thereon.

  In the crystal unit 101, the connecting bonding patterns 35 and 36 and the wiring pattern 33 are formed inside the inner space 13 (inside the inner peripheral surface of the bonding material 11) in plan view. The connection bonding patterns 35 and 36 and the wiring pattern 33 are not electrically connected to the sealing-side first bonding pattern 321. In the crystal unit 101, the A1 direction in FIG. 3 coincides with the X-axis direction in FIG. 4, and the A2 direction in FIG. 3 coincides with the Z′-axis direction in FIG.

For the second sealing member 4, a material having a bending rigidity (secondary moment of section × Young's modulus) of 1000 [N · mm ² ] or less is used. Specifically, as shown in FIGS. 6 and 7, the second sealing member 4 is a rectangular parallelepiped substrate formed from a single glass wafer, and one main surface 411 of the second sealing member 4 ( The surface to be bonded to the quartz diaphragm 2 is formed as a flat smooth surface (mirror finish).

  The main surface 411 of the second sealing member 4 is provided with a sealing-side second sealing portion 42 for joining to the crystal diaphragm 2. The sealing-side second sealing part 42 is formed with a sealing-side second bonding pattern 421 for bonding to the crystal vibrating plate 2. The sealing-side second bonding pattern 421 is formed in an annular shape in plan view. The sealing-side second bonding pattern 421 is provided so as to be close to the outer peripheral edge of the one main surface 411 of the second sealing member 4. The sealing side second bonding pattern 421 has the same width at all positions on the sealing side second sealing portion 42 of the second sealing member 4.

  The sealing-side second bonding pattern 421 is formed by stacking a base PVD film 4211 formed by physical vapor deposition on the second sealing member 4 and a physical vapor deposition on the base PVD film 4211. The electrode PVD film 4212 is formed. Note that in this embodiment, Ti (or Cr) is used for the base PVD film 4211 and Au is used for the electrode PVD film 4212. Further, the sealing-side second bonding pattern 421 is a non-Sn pattern. Specifically, the sealing-side second bonding pattern 421 is configured by laminating a plurality of layers on the sealing-side second sealing portion 42 of the other main surface 412, and Ti layer (or from the lowermost layer side) Cr layer) and Au layer are formed by vapor deposition.

  In addition, a pair of external electrode terminals (one external electrode terminal 431, etc.) electrically connected to the outside are provided on the other main surface 412 of the second sealing member 4 (an outer main surface not facing the crystal diaphragm 2). An external electrode terminal 432) is provided. As shown in FIGS. 1 and 7, the one external electrode terminal 431 and the other external electrode terminal 432 are respectively located at both ends in the longitudinal direction of the other main surface 412 of the second sealing member 4 in the plan view. The pair of external electrode terminals (one external electrode terminal 431 and the other external electrode terminal 432) are formed of a base PVD film 4311 and 4321 formed by physical vapor deposition on the other main surface 412, and a base PVD film 4311, The electrode PVD films 4312 and 4322 are formed by physical vapor deposition on 4321 and are stacked. The one external electrode terminal 431 and the other external electrode terminal 432 occupy one-third or more of the other main surface 412 of the second sealing member 4.

  As shown in FIGS. 1, 6, and 7, the second sealing member 4 includes two through-holes (second through-hole 45 and third through-hole that penetrate between the one main surface 411 and the other main surface 412. 46) is formed. The second through hole 45 is connected to one external electrode terminal 431 and the connection pattern 265 for connection of the crystal diaphragm 2. The third through hole 46 is connected to the other external electrode terminal 432 and the connection pattern 28 for connection of the crystal diaphragm 2.

  As shown in FIGS. 1, 6, and 7, the second through hole 45 and the third through hole 46 have through electrodes 451 for conducting the electrodes formed on one main surface 411 and the other main surface 412. 461 is formed along the inner wall surfaces of the second through hole 45 and the third through hole 46, respectively. The central portions of the second through hole 45 and the third through hole 46 are hollow through portions 452 and 462 that penetrate between the one main surface 411 and the other main surface 412. Connection joint patterns 453 and 463 are formed on the outer periphery of each of the second through hole 45 and the third through hole 46.

  The connection bonding patterns 453 and 463 are provided on one main surface 411 of the second sealing member 4 and are bonded to the connection bonding patterns 265 and 28 of the crystal diaphragm 2. The joint patterns for connection 453 and 463 extend along the direction in the short side direction (B1 direction in FIG. 6) of the second sealing member 4. The connecting bonding patterns 453 and 463 are provided at a predetermined interval in the long side direction (B2 direction in FIG. 6) of the second sealing member 4, and the connecting bonding patterns 453 and 463 are spaced in the B2 direction. Is substantially the same as the interval (see FIG. 5) in the Z′-axis direction of the connection pattern 265, 28 for connection of the crystal plate 2.

  The connection bonding patterns 453 and 463 have the same configuration as the sealing-side second bonding pattern 421 and can be formed by the same process as the sealing-side second bonding pattern 421. Specifically, the connection bonding patterns 453 and 463 are formed by forming a base PVD film formed by physical vapor deposition on one main surface 411 of the second sealing member 4 and a physical layer on the base PVD film. The electrode PVD film is formed by vapor deposition.

  In the crystal unit 101, the second through hole 45, the third through hole 46, and the connection bonding patterns 453 and 463 are formed inside the internal space 13 in plan view. The second through hole 45, the third through hole 46, and the connecting joint patterns 453 and 463 are not electrically connected to the sealing-side second joint pattern 421. Also, the one external electrode terminal 431 and the other external electrode terminal 432 are not electrically connected to the sealing-side second bonding pattern 421. In the crystal unit 101, the B1 direction in FIG. 6 coincides with the X-axis direction in FIG. 5, and the B2 direction in FIG. 6 coincides with the Z′-axis direction in FIG.

  In the quartz crystal resonator 101 having the above-described configuration, the quartz-crystal diaphragm 2 and the first sealing member 3 are connected to the vibration-side first bonding pattern 251 without using a dedicated bonding material such as an adhesive as in the prior art. In addition, diffusion bonding is performed in a state where the sealing-side first bonding pattern 321 is overlapped, and the crystal diaphragm 2 and the second sealing member 4 overlap the vibration-side second bonding pattern 252 and the sealing-side second bonding pattern 421. The sandwiched package 12 shown in FIG. 1 is manufactured by diffusion bonding in the combined state. Thereby, the internal space 13 of the package 12, that is, the accommodation space of the vibration part 22 is hermetically sealed. The vibration side first bonding pattern 251 and the sealing side first bonding pattern 321 itself become the bonding material 11 generated after diffusion bonding, and the vibration side second bonding pattern 252 and the sealing side second bonding pattern 421 itself diffuse. It becomes the joining material 11 produced | generated after joining. The bonding material 11 is formed in an annular shape in plan view. In this embodiment, all the wirings from the first and second excitation electrodes 221 and 222 of the crystal diaphragm 2 to the one external electrode terminal 431 and the other external electrode terminal 432 are provided inside the bonding material 11 in plan view. ing. The bonding material 11 is formed so as to be close to the outer peripheral edge of the package 12 in plan view. Thereby, the size of the vibration part 22 of the crystal diaphragm 2 can be increased.

  At this time, diffusion bonding is performed in a state where the above-described bonding patterns for connection are also overlapped. Specifically, the connection bonding pattern 264 of the crystal diaphragm 2 and the connection bonding pattern 35 of the first sealing member 3 are diffusion bonded. The connection bonding pattern 27 of the crystal diaphragm 2 and the connection bonding pattern 36 of the first sealing member 3 are diffusion bonded. In addition, the connection bonding pattern 265 of the crystal diaphragm 2 and the connection bonding pattern 453 of the second sealing member 4 are diffusion bonded. The connection bonding pattern 28 of the crystal diaphragm 2 and the connection bonding pattern 463 of the second sealing member 4 are diffusion bonded. Then, each connection bonding pattern becomes the bonding material 14 generated after diffusion bonding. These bonding materials 14 formed by diffusion bonding serve to connect the through electrodes of the through holes and the bonding material 14 and to hermetically seal the bonding portions. In addition, since the bonding material 14 is provided inward of the sealing bonding material 11 in a plan view, the bonding material 14 is indicated by a broken line in FIG.

  Here, the 1st through-hole 26 and the 2nd through-hole 45 are arrange | positioned so that it may not overlap with planar view. Specifically, as shown in FIG. 6, when viewed from the front (when viewed from the direction B1 in FIG. 6), the first through hole 26 and the second through hole 45 are arranged in a straight line up and down. . In FIG. 6, for convenience, the first through hole 26 formed in the quartz crystal plate 2 provided above the second sealing member 4 is indicated by a two-dot chain line. On the other hand, when viewed from the side (as viewed from the direction B2 in FIG. 6), the first through hole 26 and the second through hole 45 are offset and arranged so as not to line up and down. More specifically, the first through hole 26 is connected to one end in the longitudinal direction (B1 direction) of the bonding material 14 (connection bonding patterns 265 and 453), and the second through the other end in the longitudinal direction of the bonding material 14. A through hole 45 is connected. The through electrode 261 of the first through hole 26 and the through electrode 451 of the second through hole 45 are electrically connected via the bonding material 14. In this way, by arranging the first through hole 26 and the second through hole 45 so as not to overlap in plan view, the airtightness of the internal space 13 in which the vibrating portion 22 of the crystal diaphragm 2 is hermetically sealed is ensured. Therefore, a more preferable structure is obtained.

  In the package 12 manufactured as described above, the first sealing member 3 and the crystal diaphragm 2 have a gap of 1.00 μm or less, and the second sealing member 4 and the crystal diaphragm 2 Has a gap of 1.00 μm or less. That is, the thickness of the bonding material 11 between the first sealing member 3 and the crystal vibrating plate 2 is 1.00 μm or less, and the bonding material 11 between the second sealing member 4 and the crystal vibrating plate 2 The thickness is 1.00 μm or less (specifically, 0.01 μm to 1.00 μm in the Au—Au bonding of this embodiment). For comparison, a conventional metal paste sealing material using Sn has a thickness of 5 μm to 20 μm.

  In this embodiment, in the quartz crystal resonator 101 having the sandwich structure, the other main surface 312 of the first sealing member 3, that is, the surface facing the crystal vibrating plate 2, is connected to the first excitation electrode 221 of the crystal vibrating plate 2. A wiring pattern 33 to be connected is provided, and at least a part of the wiring pattern 33 is provided at a position overlapping with the space between the vibration part 22 and the outer frame part 23 in plan view. More preferably, the pattern 33 is provided at a position that does not overlap the first excitation electrode 221 and the second excitation electrode 222 in plan view.

  With this configuration, the other main surface 312 of the first sealing member 3 can be effectively used as an arrangement region for the wiring pattern 33, and the crystal unit 101 can be reduced in size while ensuring the size of the vibration unit 22. Can be achieved. That is, it is not necessary to separately secure an area for arranging the wiring pattern 33 on the crystal diaphragm 2, and the size of the vibrating portion 22 can be increased accordingly. Therefore, in order to satisfy the demand for miniaturization of the crystal unit 101, the size of the vibration unit 22 does not need to be reduced more than necessary.

  Further, since the other main surface 312 of the first sealing member 3 is formed as a flat surface, the thickness of the first sealing member 3 can be suppressed, and accordingly, the crystal resonator 101 can be reduced in height. Can contribute. That is, when the other main surface 312 of the first sealing member 3 is provided with a recess, there is a concern that the thickness of the first sealing member 3 increases by an amount corresponding to the depth of the recess. However, by forming the other main surface 312 of the first sealing member 3 as a flat surface, it is possible to suppress an increase in the thickness of the first sealing member 3, and to reduce the height of the crystal unit 101. Can contribute. In this case, since the vibration part 22 and the connecting part 24 of the crystal diaphragm 2 are formed thinner than the outer frame part 23, the vibration part 22 and the first sealing are achieved while reducing the height of the crystal resonator 101. This is effective in suppressing contact with the member 3 and the second sealing member 4.

  Moreover, in this form, although glass is used for the 1st sealing member 3 and the 2nd sealing member 4, it is not limited to this, You may use a crystal.

  The above-described embodiments and examples of the present invention are all examples of the present invention, and are not of a nature that limits the technical scope of the present invention. In each of the above embodiments, the crystal resonator device is a crystal resonator, but the present invention can also be applied to a crystal resonator device (for example, a crystal oscillator) other than the crystal resonator.

  The present invention is suitable for a crystal vibration device (a crystal resonator, a crystal oscillator, or the like) using quartz as a material for a substrate of a piezoelectric vibration plate.

DESCRIPTION OF SYMBOLS 101 Crystal resonator 12 Package 13 Internal space 2 Crystal diaphragm 21 Cutout part 22 Vibration part 221 1st excitation electrode 222 2nd excitation electrode 223 1st extraction electrode 224 2nd extraction electrode 23 Outer frame part 24 Connection part 3 1st sealing Stop member 4 Second sealing member

Claims (2)

An AT-cut quartz crystal plate having a rectangular shape in plan view having one main surface and another main surface,
In the central part of the quartz crystal diaphragm, a first excitation electrode is formed on one main surface and a second vibration electrode is formed on the other main surface in a rectangular shape in plan view;
A cutout portion formed on the outer periphery of the vibrating portion;
An outer frame portion formed on the outer periphery of the cutout portion and having an inner peripheral end having a rectangular shape in plan view,
The vibration part and the outer frame part are connected, and one connecting part extended along the Z′-axis direction of the vibration part from one end part of the vibration part along the X-axis direction is provided. And
A convex portion is formed at the inner peripheral end in the Z′-axis direction of the outer frame portion adjacent to the corner portion of the diagonal vibration portion with respect to the corner portion of the vibration portion to which the coupling portion is connected. A crystal diaphragm characterized by A crystal diaphragm according to claim 1;
A first sealing member that covers one main surface of the crystal diaphragm;
A quartz vibrating device comprising: a second sealing member that covers the other main surface of the quartz vibrating plate.

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