JP2019009565A - Quartz diaphragm and quartz vibrating device - Google Patents

Abstract

Kind Code: A1 A quartz crystal diaphragm and a quartz crystal oscillation device are provided that can reduce vibration leakage from a vibrating portion and at the same time suppress disconnection or the like in lead wiring. Kind Code: A1 In a crystal diaphragm plate, a holding portion extends from only one corner portion of a vibrating portion located in +X and -Z' directions to an outer frame portion in a -Z' direction. there is At least a part of the vibrating portion 22 and the holding portion 24 is formed as an etched region Eg having a thickness thinner than that of the outer frame portion 23. A step is formed at the boundary between the etched regions Eg, and the first drawer A wiring 223 is formed from the holding portion 24 to the outer frame portion 23 so as to overlap the step. At least part of the step overlapping the first extraction wiring 223 is formed so as not to be parallel to the X-axis in plan view. [Selection drawing] Fig. 10

Description

  According to the present invention, an AT-cut type crystal plate includes: a vibrating portion in which an excitation electrode is formed; an outer frame portion disposed around the vibrating portion; and a holding portion that holds the vibrating portion connected to the outer frame portion. And a quartz crystal vibrating device provided with the quartz crystal vibrating plate.

  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, as the frequency becomes higher and the package becomes smaller, crystal vibrating devices (for example, crystal resonators, crystal oscillators, etc.) are also required to respond to higher frequencies and smaller packages.

  A so-called sandwich structure crystal vibration device is known as a crystal vibration device suitable for miniaturization and low profile. The quartz crystal vibration device having a sandwich structure is configured by a substantially rectangular parallelepiped package. This package includes a first sealing member and a second sealing member made of, for example, glass or crystal, and a crystal diaphragm having excitation electrodes formed on both main surfaces. The first sealing member and the second sealing member The stop member is laminated and bonded through the quartz diaphragm. And the vibration part of the crystal diaphragm arranged inside the package (internal space) is hermetically sealed by the first sealing member and the second sealing member.

  The quartz crystal plate used in the quartz crystal device with sandwich structure has a vibrating part with an excitation electrode, an outer frame part arranged around the vibrating part, and a vibrating part connected to the outer frame part. The holding portion is integrally formed on the quartz plate. As this quartz diaphragm, an AT cut type quartz plate that is easy to process and excellent in frequency temperature characteristics is most widely used.

  In the crystal diaphragm in which the vibration part, the outer frame part, and the holding part are integrally formed, there is a problem of vibration leakage such that the piezoelectric vibration generated in the vibration part easily leaks to the outer frame part through the holding part. On the other hand, Patent Document 1 discloses a crystal diaphragm that suppresses such vibration leakage.

  Specifically, Patent Document 1 discloses a configuration in which a holding portion is formed by projecting from a vibrating portion in an AT-cut Z′-axis direction. Here, the crystal axes of the artificial quartz are the X-axis, Y-axis, and Z-axis, and the Y-axis and Z-axis of the AT-cut type crystal rotated by 35 ° 15 ′ around the X-axis are respectively the Y′-axis, The Z ′ axis is assumed.

  In the AT-cut type quartz diaphragm, it is known that the displacement of the piezoelectric vibration along the X-axis direction is larger than the displacement of the piezoelectric vibration along the Z′-axis direction in the vibration portion. In the configuration of Patent Document 1, the holding unit holds the vibrating unit along the Z′-axis direction in which the displacement of piezoelectric vibration is small. For this reason, when the crystal diaphragm is subjected to piezoelectric vibration, the piezoelectric vibration is less likely to leak through the holding portion, and the vibration portion can be efficiently piezoelectrically vibrated.

International Publication No. 2016/121182

  While the quartz diaphragm disclosed in Patent Document 1 has a configuration suitable for suppressing vibration leakage from the vibration part, there is a problem that problems such as disconnection are likely to occur in the extraction electrode of the excitation electrode. This problem will be described below.

  The crystal diaphragm is manufactured by forming an outer shape of the crystal plate by an etching process and then forming electrodes and wirings on both main surfaces of the crystal plate. In the etching step, at least two etching processes of outer shape formation etching and frequency adjustment etching are performed on the rectangular crystal plate. In addition, when a mesa structure is formed in the center of the vibration part, mesa formation etching may be additionally performed.

  In the outer shape forming etching, a cutout portion is formed in a rectangular crystal plate, and outer shapes of a vibrating portion, a holding portion, and an outer frame portion are formed. In the frequency adjustment etching, the thickness of the vibrating part and the holding part is adjusted in order to set the oscillation frequency of the crystal vibrating device to a predetermined value. In the frequency adjustment etching, basically the regions of the vibration part and the holding part are etched.

  When the frequency adjustment etching is performed on the region of the vibration part and the holding part, a step due to the thickness difference of the crystal plate is formed at the boundary between the holding part and the outer frame part. When the holding portion is formed by projecting from the vibrating portion in the Z′-axis direction of the AT cut, the boundary between the holding portion and the outer frame portion is a boundary parallel to the X axis. Therefore, the step is also formed along a line parallel to the X axis.

  The cross-sectional shape of the step is affected by the crystal anisotropy of the quartz plate, and in the case of a boundary parallel to the X axis, at least one main surface has a cross section perpendicular to the main surface. It becomes a step. In addition, when the step is formed so as to be shifted toward the holding part, a hollow cross section may be formed in a part of the step. In addition, the hollow shape here is such that the side surface of the step is further inclined from the vertical, and the angle formed between the side surface of the step and the main surface (the main surface of the holding portion or the main surface of the outer frame portion) is an acute angle. Refers to the shape.

  In the quartz diaphragm, the lead-out wiring connected to the excitation electrode formed in the vibration part is formed up to the outer frame part through the holding part, so that the lead-out wiring is at the boundary between the holding part and the outer frame part. It is necessary to cross the step. The lead-out wiring is formed by forming a metal film by sputtering and then patterning the metal film.

  The lead wiring formed in this way has a problem that, when a vertical step is formed at the boundary between the holding portion and the outer frame portion, it is difficult to secure a metal film thickness by sputtering, and disconnection in the lead wiring is likely to occur. . Alternatively, even if the disconnection does not occur, there is a possibility that the lead-out wiring may have a high resistance due to the thinning of the wiring. Increasing the resistance of the lead-out line in the excitation electrode adversely affects the vibration characteristics of the crystal vibrating device. In addition, the above problem becomes more prominent when a hollow cross section occurs at the step.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a quartz crystal vibrating plate and a quartz crystal vibrating device that can reduce vibration leakage from a vibrating portion and at the same time suppress disconnection or the like in a lead-out wiring. .

  In order to solve the above problems, a quartz crystal diaphragm according to the present invention has a substantially rectangular shape including a first excitation electrode formed on one main surface and a second excitation electrode formed on the other main surface. A vibration part, a holding part for holding the vibration part, which protrudes from the corner part of the vibration part in the Z′-axis direction of the AT cut, and an outer frame that surrounds the outer periphery of the vibration part and holds the holding part A boundary between the holding part and the outer frame part on a side parallel to the X axis in the inner periphery of the outer frame part. In this case, at least a part of the vibration part and the holding part is an etching region whose thickness is smaller than that of the outer frame part, and the holding part and the outer frame part are formed by the etching region. A step is formed near the boundary, and the first excitation electrode and the second excitation electrode An outgoing wiring is formed from the holding portion to the outer frame portion so as to overlap the step, and at least one of the one main surface and the other main surface is a portion of the portion overlapping the leading wiring. It is characterized in that at least a part of the step is formed so as not to be parallel to the X axis in plan view.

  In the etching region for making the holding portion thinner than the outer frame portion, a step due to the thickness difference of the quartz plate is formed at the boundary of the etching region. This step has a vertical cross section (possibly a cross section in some cases) at least one of the one main surface and the other main surface at a portion where the boundary of the etching region is parallel to the X axis. On the other hand, according to the above configuration, a portion that is not parallel to the X axis in plan view is formed in at least a part of the step of the portion that overlaps with the lead wiring. Since a gentle step can be formed at this portion, disconnection of the lead-out wiring on the step can be suppressed.

  Further, the quartz crystal plate may be configured such that at least a part of the step of the portion overlapping with the lead-out wiring is formed as a straight portion that is not parallel to the X axis in plan view.

  According to the above configuration, by forming at least a part of the step overlapped with the lead wiring as a straight part, a gentle step part can be formed long, and the disconnection of the lead wiring on the step is more effective. Can be suppressed.

  In the quartz diaphragm, the linear portion may be configured to be orthogonal to the X axis in plan view.

  According to the above configuration, the step becomes gentler as it approaches the angle orthogonal to the X axis in plan view, and the step becomes the gentlest in the portion formed to be orthogonal to the X axis in plan view. It is possible to more effectively suppress disconnection or the like of the lead-out wiring.

  Moreover, in the above-mentioned quartz diaphragm, the length of the straight line portion can be a half or more of the line width of the lead-out wiring. Alternatively, in the above-described quartz diaphragm, the length of the straight portion can be greater than or equal to the line width of the lead-out wiring.

  According to said structure, the disconnection of an extraction wiring, etc. can be suppressed more effectively by making the straight part longer than the line width of an extraction wiring.

  Further, in the above-described quartz diaphragm, the step can be configured to be formed closer to the outer frame part than the boundary between the holding part and the outer frame part.

  According to said structure, while being able to improve the intensity | strength of a holding | maintenance part, it can also prevent that a hollow-shaped cross section arises in a level | step difference.

  Further, in the quartz crystal plate, at least one of the one main surface and the other main surface, the etching region has an intrusion portion formed by entering a part of the outer frame portion from the holding portion. The boundary line of the etching region in the entry portion is the step, and the start point on the −X side of the step is formed inside the connection region between the holding portion and the outer frame portion. It can be.

  According to said structure, the junction area with the sealing member in an outer frame part is securable by suppressing the area of a penetration part. As a result, it is possible to suppress a decrease in bonding strength and sealing performance in the quartz crystal vibration device.

  Further, in order to solve the above-described problem, a quartz crystal vibrating device of the present invention includes the quartz crystal plate described above, a first sealing member that covers the one main surface of the quartz crystal plate, and the quartz crystal plate. A second sealing member that covers the other main surface is provided.

  In the quartz crystal plate and the quartz crystal vibrating device of the present invention, a gentle step portion is formed at the boundary of the etching region in the vicinity of the connection portion between the outer frame portion and the holding portion, and the excitation electrode is formed so as to exceed the gentle step portion. By forming the lead-out wiring, there is an effect that it is possible to prevent the disconnection of the wiring and the increase in resistance on the step generated at the boundary of the etching region.

It is the schematic block diagram which showed typically each structure of the crystal oscillator concerning this Embodiment. FIG. 2 is a schematic plan view of the first main surface side of the first sealing member of the crystal oscillator. FIG. 3 is a schematic plan view of the second main surface side of the first sealing member of the crystal oscillator. FIG. 4 is a schematic plan view of the first main surface side of the crystal diaphragm of the crystal oscillator. FIG. 5 is a schematic plan view of the second main surface side of the crystal diaphragm of the crystal oscillator. FIG. 6 is a schematic plan view on the first main surface side of the second sealing member of the crystal oscillator. FIG. 7 is a schematic plan view of the second main surface side of the second sealing member of the crystal oscillator. It is a figure which shows the state immediately after performing the etching process to a crystal plate in a crystal diaphragm, (a) is a schematic plan view of the 1st main surface side, (b) is a schematic plan view of the 2nd main surface side. It is. It is an enlarged view which shows the connection location vicinity of the holding | maintenance part and outer frame part in a crystal diaphragm, (a) is a schematic plan view of the 1st main surface side, (b), (c) is the 1st main surface side. FIG. 3D is a schematic sectional view, and FIG. 4D is a schematic sectional view on the second main surface side. It is an enlarged view which shows the connection location vicinity of the holding | maintenance part and outer frame part in a quartz-crystal diaphragm, and is a schematic plan view which shows the shape of an etching area | region and extraction wiring. It is an enlarged view which shows the connection location vicinity of the holding | maintenance part and outer frame part in a quartz-crystal diaphragm, (a), (b) is a schematic plan view which shows the modification of the shape of an etching area | region and extraction wiring. It is an enlarged view which shows the connection location vicinity of the holding | maintenance part and outer frame part in a quartz-crystal diaphragm, (a), (b) is a schematic plan view which shows the modification of the shape of an etching area | region and extraction wiring. It is an enlarged view which shows the connection location vicinity of the holding | maintenance part and outer frame part in a quartz-crystal diaphragm, and is a schematic plan view which shows the modification of the shape of an etching area | region and extraction wiring.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the case where the crystal oscillation device to which the present invention is applied is a crystal oscillator will be described. However, the crystal vibration device to which the present invention is applicable is not limited to the crystal oscillator, and the present invention may be applied to a crystal resonator.

-Crystal oscillator-
As shown in FIG. 1, the crystal oscillator 101 according to the present embodiment includes a crystal diaphragm 2, a first sealing member 3, a second sealing member 4, and an IC chip 5. In this crystal oscillator 101, the quartz diaphragm 2 and the first sealing member 3 are joined, and the quartz diaphragm 2 and the second sealing member 4 are joined, so that the package 12 having a substantially rectangular parallelepiped sandwich structure is formed. Composed. In addition, the IC chip 5 is mounted on the main surface of the first sealing member 3 opposite to the bonding surface with the crystal diaphragm 2. The IC chip 5 as an electronic component element is a one-chip integrated circuit element that constitutes an oscillation circuit together with the crystal diaphragm 2.

  In the quartz diaphragm 2, the first excitation electrode 221 is formed on the first main surface 211 that is one main surface, and the second excitation electrode 222 is formed on the second main surface 212 that is the other main surface. In the crystal oscillator 101, the first sealing member 3 and the second sealing member 4 are bonded to both main surfaces (the first main surface 211 and the second main surface 212) of the crystal diaphragm 2, respectively. Thus, an internal space of the package 12 is formed, and the vibrating portion 22 (see FIGS. 4 and 5) including the first excitation electrode 221 and the second excitation electrode 222 is hermetically sealed in the internal space.

  The crystal oscillator 101 according to the present embodiment has a package size of, for example, 1.0 × 0.8 mm, and is intended to be reduced in size and height. In addition, with the miniaturization, the package 12 does not form a castellation but uses a through-hole described later to conduct the electrodes.

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

  As shown in FIGS. 4 and 5, the crystal diaphragm 2 is a piezoelectric substrate made of crystal, and both main surfaces (first main surface 211 and second main surface 212) are flat and smooth surfaces (mirror finish). Is formed. In the present embodiment, an AT-cut quartz plate that performs thickness shear vibration 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 axes tilted by 35 ° 15 ′ from the Y axis and the Z axis of the crystal axis of the crystal, respectively. The Y′-axis direction and the Z′-axis direction correspond to the cutting direction when cutting the AT-cut quartz plate.

  A pair of excitation electrodes (a first excitation electrode 221 and a second excitation electrode 222) are formed on both main surfaces 211 and 212 of the crystal diaphragm 2. The quartz crystal diaphragm 2 holds the vibration part 22 by connecting the vibration part 22 formed in a substantially rectangular shape, the outer frame part 23 surrounding the outer periphery of the vibration part 22, and the vibration part 22 and the outer frame part 23. Holding part 24. That is, the crystal diaphragm 2 has a configuration in which the vibration part 22, the outer frame part 23, and the holding part 24 are integrally provided.

  In the present embodiment, the holding portion 24 is provided only at one place between the vibrating portion 22 and the outer frame portion 23. As will be described in detail later, the vibrating portion 22 and the holding portion 24 are basically formed thinner than the outer frame portion 23. Due to the difference in thickness between the outer frame portion 23 and the holding portion 24, the natural frequency of the piezoelectric vibration of the outer frame portion 23 and the holding portion 24 is different, and the outer frame portion 23 is affected by the piezoelectric vibration of the holding portion 24. Is less likely to resonate. In addition, the formation part of the holding | maintenance part 24 is not limited to one place, The holding | maintenance part 24 is two places (for example, both sides of -Z 'axial direction) between the vibration part 22 and the outer frame part 23. May be provided.

  The holding part 24 extends (protrudes) from only one corner located in the + X direction and the −Z ′ direction of the vibration part 22 to the outer frame part 23 in the −Z ′ direction. Thus, since the holding part 24 is provided in the corner | angular part where the displacement of a piezoelectric vibration is comparatively small among the outer peripheral edge parts of the vibration part 22, a part other than a corner | angular part (side center part) Compared with the case where it is provided, the leakage of the piezoelectric vibration to the outer frame portion 23 via the holding portion 24 can be suppressed, and the vibration portion 22 can be more efficiently piezoelectrically vibrated. In addition, compared to the case where two or more holding parts 24 are provided, the stress acting on the vibration part 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.

  The first excitation electrode 221 is provided on the first main surface 211 side of the vibration unit 22, and the second excitation electrode 222 is provided on the second main surface 212 side of the vibration unit 22. The first excitation electrode 221 and the second excitation electrode 222 are connected to lead wires (first lead wire 223 and second lead wire 224) for connecting these excitation electrodes to the external electrode terminals. The first lead wiring 223 is drawn from the first excitation electrode 221 and is connected to the connection bonding pattern 27 formed on the outer frame portion 23 via the holding portion 24. The second lead wiring 224 is drawn from the second excitation electrode 222 and is connected to the connection pattern 28 for connection formed on the outer frame portion 23 via the holding portion 24. As described above, the first lead wiring 223 is formed on the first main surface 211 side of the holding portion 24, and the second lead wiring 224 is formed on the second main surface 212 side of the holding portion 24.

  On both main surfaces (the first main surface 211 and the second main surface 212) of the crystal diaphragm 2, a vibration side seal for joining the crystal diaphragm 2 to the first sealing member 3 and the second sealing member 4 is provided. Each stop is provided. As the vibration side sealing portion of the first main surface 211, a vibration side first bonding pattern 251 for bonding to the first sealing member 3 is formed. In addition, as the vibration side sealing portion of the second main surface 212, a vibration side second bonding pattern 252 for bonding to the second sealing member 4 is formed. The vibration side first joining pattern 251 and the vibration side second joining pattern 252 are provided on the outer frame portion 23 and are formed in an annular shape in plan view. The first excitation electrode 221 and the second excitation electrode 222 are not electrically connected to the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252.

  In addition, as shown in FIGS. 4 and 5, the crystal diaphragm 2 is formed with five through holes penetrating between the first main surface 211 and the second main surface 212. Specifically, the four first through holes 261 are respectively provided in the four corners (corner portions) of the outer frame portion 23. The second through hole 262 is the outer frame portion 23 and is provided on one side of the vibrating portion 22 in the Z′-axis direction (the + Z ′ direction side in FIGS. 4 and 5). A connection bonding pattern 253 is formed around each of the first through holes 261. In addition, around the second through hole 262, a connection bonding pattern 254 is formed on the first main surface 211 side, and a connection bonding pattern 28 is formed on the second main surface 212 side.

  In the first through hole 261 and the second through hole 262, through electrodes for conducting the electrodes formed on the first main surface 211 and the second main surface 212 are provided along the inner wall surfaces of the through holes. Is formed. Further, the central portion of each of the first through hole 261 and the second through hole 262 is a hollow through portion that penetrates between the first main surface 211 and the second main surface 212.

  In the crystal diaphragm 2, the first excitation electrode 221, the second excitation electrode 222, the first extraction wiring 223, the second extraction wiring 224, the first bonding pattern 251, the vibration side second bonding pattern 252, and the connection bonding pattern 253. , 254, 27, and 28 can be formed by the same process. Specifically, these are formed by laminating a base film formed by physical vapor deposition on both main surfaces 211 and 212 of the crystal diaphragm 2, and by physical vapor deposition on the base film. And a bonding film. In this embodiment, Ti (or Cr) is used for the base film, and Au is used for the bonding film.

  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 second main surface 312 (the crystal diaphragm 2) of the first sealing member 3 is used. Is formed as a flat and smooth surface (mirror finish).

  On the first main surface 311 (surface on which the IC chip 5 is mounted) of the first sealing member 3, as shown in FIG. 2, there are six electrode patterns including mounting pads on which the IC chip 5 that is an oscillation circuit element is mounted. 37 is formed. The IC chip 5 is bonded to the electrode pattern 37 by a FCB (Flip Chip Bonding) method using metal bumps (for example, Au bumps) 38 (see FIG. 1).

  As shown in FIGS. 2 and 3, the first sealing member 3 is connected to each of the six electrode patterns 37 and has six through holes penetrating between the first main surface 311 and the second main surface 312. Is formed. Specifically, four third through holes 322 are provided in the four corners (corner portions) of the first sealing member 3. The fourth and fifth through holes 323 and 324 are respectively provided in the A2 direction and the A1 direction in FIGS. 2, 3, 6, and 7 directions coincide with the −Z ′ direction and the + Z ′ direction in FIGS. 4, 5, respectively, and the B1 and B2 directions in FIGS. This corresponds to the −X direction and the + X direction in FIGS.

  In the third through-hole 322 and the fourth and fifth through-holes 323 and 324, through-electrodes for conducting the electrodes formed on the first main surface 311 and the second main surface 312 are provided in the respective through-holes. It is formed along the inner wall surface. In addition, the central portion of each of the third through hole 322 and the fourth and fifth through holes 323 and 324 becomes a hollow through portion that penetrates between the first main surface 311 and the second main surface 312.

  On the second main surface 312 of the first sealing member 3, a sealing-side first bonding pattern 321 is formed as a sealing-side first sealing portion for bonding to the crystal diaphragm 2. The sealing side first bonding pattern 321 is formed in an annular shape in plan view.

  Further, on the second main surface 312 of the first sealing member 3, connection bonding patterns 34 are formed around the third through holes 322, respectively. A connection bonding pattern 351 is formed around the fourth through hole 323, and a connection bonding pattern 352 is formed around the fifth through hole 324. Further, a connection bonding pattern 353 is formed on the opposite side (A2 direction side) of the first sealing member 3 with respect to the connection bonding pattern 351, and the connection bonding pattern 351 is connected to the connection bonding pattern 351. The pattern 353 is connected by the wiring pattern 33. The connection bonding pattern 353 is not connected to the connection bonding pattern 352.

  In the first sealing member 3, the sealing-side first bonding pattern 321, the connecting bonding patterns 34, 351 to 353, and the wiring pattern 33 can be formed by the same process. Specifically, these are a base film formed by physical vapor deposition on the second main surface 312 of the first sealing member 3 and a physical vapor deposition on the base film to form a stacked layer. And the formed bonding film. In this embodiment, Ti (or Cr) is used for the base film, and Au is used for the bonding film.

  The second sealing member 4 is a rectangular parallelepiped substrate formed of a single glass wafer as shown in FIGS. 6 and 7, and the first main surface 411 (the crystal diaphragm 2) of the second sealing member 4. Is formed as a flat and smooth surface (mirror finish).

  On the first main surface 411 of the second sealing member 4, a sealing-side second bonding pattern 421 is formed as a sealing-side second sealing portion for bonding to the crystal diaphragm 2. The sealing-side second bonding pattern 421 is formed in an annular shape in plan view.

  Four external electrode terminals 43 that are electrically connected to the outside are provided on the second main surface 412 of the second sealing member 4 (the outer main surface that does not face the crystal diaphragm 2). The external electrode terminals 43 are located at the four corners (corners) of the second sealing member 4, respectively.

  As shown in FIGS. 6 and 7, the second sealing member 4 has four through holes penetrating between the first main surface 411 and the second main surface 412. Specifically, the four sixth through holes 44 are provided in regions of four corners (corner portions) of the second sealing member 4. In the sixth through hole 44, a through electrode for conducting the electrodes formed on the first main surface 411 and the second main surface 412 is formed along the inner wall surface of each through hole. Further, the central portion of each of the sixth through holes 44 becomes a hollow through portion that penetrates between the first main surface 411 and the second main surface 412. Further, on the first main surface 411 of the second sealing member 4, connection bonding patterns 45 are formed around the sixth through holes 44.

  In the second sealing member 4, the sealing-side second bonding pattern 421 and the connecting bonding pattern 45 can be formed by the same process. Specifically, these are a base film formed by physical vapor deposition on the first main surface 411 of the second sealing member 4 and a physical vapor deposition on the base film to form a stacked layer. And the formed bonding film. In this embodiment, Ti (or Cr) is used for the base film, and Au is used for the bonding film.

  In the crystal oscillator 101 including the quartz crystal plate 2, the first sealing member 3, and the second sealing member 4, the quartz plate 2 and the first sealing member 3 are connected to the vibration side first bonding pattern 251 and the sealing. Diffusion bonding is performed in a state where the stop-side first bonding pattern 321 is overlaid, 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 package 12 having the sandwich structure shown in FIG. 1 is manufactured by diffusion bonding in the state. As a result, the internal space of the package 12, that is, the accommodation space of the vibration part 22 is hermetically sealed.

  At this time, diffusion bonding is performed in a state where the above-described bonding patterns for connection are also overlapped. In the crystal oscillator 101, electrical conduction between the first excitation electrode 221, the second excitation electrode 222, the IC chip 5, and the external electrode terminal 43 is obtained by bonding the connection bonding patterns.

  Specifically, the first excitation electrode 221 includes the first lead-out wiring 223, the junction between the connection junction pattern 27 and the connection junction pattern 353, the wiring pattern 33, the connection junction pattern 351, and the fourth through-hole 323. The through-electrodes and the electrode pattern 37 are sequentially connected to the IC chip 5. The second excitation electrode 222 includes a second lead wire 224, a connection bonding pattern 28, a through electrode in the second through hole 262, a connection portion between the connection bonding pattern 254 and the connection bonding pattern 352, and a fifth through hole 324. It is connected to the IC chip 5 through the through electrode and the electrode pattern 37 in order. Further, the IC chip 5 includes an electrode pattern 37, a through electrode in the third through hole 322, a joint portion between the connection joint pattern 34 and the connection joint pattern 253, a through electrode in the first through hole 261, and a connection joint. The pattern 253 is connected to the external electrode terminal 43 through the junction between the connection junction pattern 45 and the through electrode in the sixth through hole 44 in order.

  The above is the basic structure of the crystal oscillator 101 according to the present embodiment. The feature of the present invention is that the shape of the step portion generated by the difference in thickness between the outer frame portion 23 and the holding portion 24 in the crystal diaphragm 2. And the positional relationship of the lead wires formed in the stepped portion. This feature point will now be described in detail.

  FIG. 8 is a diagram showing a state of the crystal diaphragm 2 immediately after the etching process is performed on the crystal plate (before electrodes and wirings are formed). FIG. 8A is a diagram illustrating the first main surface 211 side. FIG. 4B is a plan view of the second main surface 212 side. In the example shown in FIG. 8, the case where the mesa structure is not formed in the center of the vibrating portion is illustrated, and the rectangular crystal plate is subjected to two etching processes of outer shape formation etching and frequency adjustment etching. Shall.

  In the outer shape formation etching, cutout portions are formed in a rectangular crystal plate, and outer shapes of the vibrating portion 22, the outer frame portion 23, and the holding portion 24 are formed. In addition, the through hole in the crystal diaphragm 2 is also formed by the outer shape forming etching.

  The frequency adjustment etching is an etching process for adjusting the thicknesses of the vibration part 22 and the holding part 24 in order to set the oscillation frequency of the crystal vibration device to a predetermined value. In FIG. 8, the etching region Eg by frequency adjustment etching is indicated by hatching. The etching region Eg includes the vibration part 22 and at least a part of the holding part 24, and is thinner than the outer frame part 23.

  A step due to a difference in thickness of the quartz plate is formed at the boundary of the etching region Eg. At this time, if the boundary line forming the step is parallel to the X axis, the step has a step having a cross section perpendicular to the main surface of the crystal plate, or in some cases, the side surface of the step is further inclined from the vertical. In addition, as described above, the side surface of the step and the main surface (the main surface of the holding portion or the main surface of the outer frame portion) have an acute shape with an acute angle. Further, as described above, when the lead-out wiring from the excitation electrode is formed so as to exceed such a step in the vertical cross section or a step having a hollow shape, the lead-out wiring is likely to be disconnected.

  And in this Embodiment, the holding | maintenance part 24 is extended to the outer frame part 23 toward the -Z 'direction from only one corner | angular part located in + X direction and -Z' direction of the vibration part 22 ( Protruding). In this case, the boundary between the holding portion 24 and the outer frame portion 23 exists on a side parallel to the X axis in the inner periphery of the outer frame portion. Therefore, when the boundary of the etching region Eg is aligned with the boundary between the holding portion 24 and the outer frame portion 23 (see FIG. 9A), as described above, a step in the vertical cross section occurs at the boundary of the etching region Eg ( 9 (b)), a step having a hollow shape may occur (see FIG. 9 (c)). However, such a step in the vertical cross section does not occur on both main surfaces due to crystal anisotropy of the quartz plate, but basically occurs only on one main surface. That is, if the boundary of the etching region Eg on the first main surface 211 side is a step in the vertical cross section, the boundary of the etching region Eg on the second main surface 212 side is a gentle step (see FIG. 9D). . The gentle step here is a shape in which the side surface of the step is inclined and the angle formed between the side surface of the step and the main surface (the main surface of the holding portion or the main surface of the outer frame portion) is an obtuse angle. Point to.

  The crystal diaphragm 2 according to the present embodiment is characterized in that the boundary shape of the etching region Eg is devised in order to suppress disconnection or the like in the lead wiring from the excitation electrode. However, since such a device requires only one main surface (here, the first main surface 211) of the quartz plate, the other main surface (here, the second main surface 212) is conventionally used. As described above, the boundary of the etching region Eg may be aligned with the boundary between the holding portion 24 and the outer frame portion 23 (see FIG. 8B).

  On the first main surface 211 of the quartz diaphragm 2 to which measures for suppressing disconnection, which is a feature of the present invention, are provided, the boundary of the etching region Eg is made the boundary between the holding portion 24 and the outer frame portion 23 as shown in FIG. Without matching, at least a part of the boundary of the etching region Eg is defined as a boundary line L1 that is not parallel to the X axis. In this case, the step generated at the boundary line L1 is not a vertical step or a step having a hollow shape, but a gentle step. And the 1st lead-out wiring 223 formed in the 1st main surface 211 is formed so that at least one part of the boundary line L1 may be exceeded.

  Thereby, at least a part of the step of the portion overlapping with the first lead-out wiring 223 is formed so as not to be parallel to the X axis in plan view. Of the step overlapped with the first lead-out wiring 223, the first lead-out wiring 223 is formed on the gentle step at the portion not parallel to the X axis. As a result, disconnection and high resistance of the first lead-out wiring 223 can be suppressed.

  Note that the shape of the boundary of the etching region Eg is not limited to the example shown in FIG. 10, and various other shape examples are conceivable. Several modified examples of the boundary shape of the etching region Eg are shown in FIGS. 11A, 11B, 12A, 12B, and 13. FIG.

  In the example illustrated in FIG. 10, the boundary of the etching region Eg includes not only the boundary line L1 that is not parallel to the X axis, but partly the boundary line L2 that is parallel to the X axis. However, as shown in FIGS. 11A, 11B, and 13, all of the boundaries of the etching region Eg may be a boundary line L1 that is not parallel to the X axis.

  Further, the boundary line L1 that is not parallel to the X-axis may be a curved line (for example, an arc) in a plan view as shown in FIG. 11A, and FIG. 11B, FIG. ) And a straight line in plan view as shown in FIG. However, if the boundary line L1 is a straight line, a gentle step portion can be formed longer. Therefore, at least a part of the step overlapping the first lead wire 223 is at least part of the first lead wire 223 on the step. In order to suppress breakage and the like more effectively, it is preferably formed as a straight portion.

  Further, the boundary line L1 formed as a straight line is preferably formed so as to be orthogonal to the X axis in plan view, as shown in FIGS. 12 (a) and 12 (b). This is because the step becomes gentler as it approaches the angle orthogonal to the X axis in plan view, and becomes the gentlest at the portion formed to be orthogonal to the X axis. That is, the disconnection of the first lead-out wiring 223 can be more effectively suppressed by setting at least a part of the step overlapping the first lead-out wiring 223 to a straight line orthogonal to the X axis.

  In addition, when providing a linear part in the level | step difference which overlaps with the 1st extraction wiring 223, it is preferable that the length W1 of this linear part shall be more than half of the line width W2 of the 1st extraction wiring 223 (refer FIG.12 (b)). ). Furthermore, in the case where a straight line portion is provided at a step overlapping with the first lead-out wiring 223, the length of the straight line portion is preferably equal to or larger than the line width of the first lead-out wiring 223 (FIG. 11B, FIG. a)). That is, as the length of the straight line portion is increased with respect to the line width of the first lead-out wiring 223, disconnection or the like of the first lead-out wiring 223 can be more effectively suppressed.

  In addition, in the examples of FIGS. 10, 11 (a), 11 (b) and 12 (a), 12 (b), the boundary (that is, the step) of the etching region Eg is the boundary between the holding portion 24 and the outer frame portion 23. It is formed on the outer frame portion 23 side. However, the present invention is not limited to this, and as shown in FIG. 13, the boundary of the etching region Eg is formed closer to the holding part 24 than the boundary between the holding part 24 and the outer frame part 23. Also good. However, when the step is formed on the holding portion 24 side, the above-mentioned cross-sectional shape tends to occur at the + X side boundary at the step, and therefore, to prevent this, the boundary of the etching region Eg is It is preferably formed on the outer frame portion 23 side.

  Further, when the boundary (that is, the step) of the etching region Eg is formed closer to the outer frame portion 23 than the boundary between the holding portion 24 and the outer frame portion 23, the etching region Eg enters a part of the outer frame portion 23. It has an intrusion formed. The start point P on the −X side of the entering portion can be formed inside the connection region R between the holding portion 24 and the outer frame portion 23 as shown in FIG. 10. In this configuration, by suppressing the area of the entering portion, it is possible to secure a bonding area between the outer frame portion 23 and the sealing member (the first sealing member 3 and the second sealing member 4). As a result, it is possible to suppress a decrease in bonding strength and sealing performance in the crystal vibrating device (for example, the crystal oscillator 101).

  In addition, when the entry portion is formed in the outer frame portion 23, if the starting point P is formed on the extension line of the side on the −X side of the holding portion 24, the holding portion 24 and the outer portion are removed during frequency adjustment etching. It has been found by the present inventor that a depression is generated at the connection portion with the frame portion 23. When such a dent occurs, the dent becomes a stress concentration point at the connecting portion between the holding portion 24 and the outer frame portion 23, and the impact resistance of the quartz crystal vibration device is lowered. As shown in FIG. 10, in the configuration in which the starting point P is formed inside the connection region R between the holding portion 24 and the outer frame portion 23, the occurrence of the depression can be avoided, and as a result, the impact resistance in the crystal vibrating device can be reduced. Decline can be prevented.

  The embodiments disclosed herein are illustrative in all respects and do not serve as a basis for limited interpretation. Therefore, the technical scope of the present invention is not interpreted only by the above-described embodiments, but is defined based on the description of the scope of claims. Further, all modifications within the meaning and scope equivalent to the scope of the claims are included.

2 crystal vibrating plate 3 first sealing member 4 second sealing member 5 IC chip 12 package 22 vibration part 23 outer frame part 24 holding part 101 crystal oscillator (crystal oscillation device)
211 1st main surface 212 2nd main surface 221 1st excitation electrode 222 2nd excitation electrode 223 1st extraction wiring 224 2nd extraction wiring Eg Etching area | region L1 The boundary line which is not parallel to an X-axis

Claims (8)

A substantially rectangular vibrating portion provided with a first excitation electrode formed on one main surface and a second excitation electrode formed on the other main surface;
A holding part that protrudes in the Z′-axis direction of the AT cut from the corner part of the vibration part and holds the vibration part;
An AT-cut type quartz diaphragm that surrounds the outer periphery of the vibrating part and has an outer frame part that holds the holding part,
When the boundary between the holding part and the outer frame part is on the side parallel to the X axis in the inner periphery of the outer frame part,
At least a part of the vibration part and the holding part is an etching region having a thickness smaller than that of the outer frame part, and the etching region causes the vicinity of the boundary between the holding part and the outer frame part. A step is formed,
The lead wires of the first excitation electrode and the second excitation electrode are formed from the holding portion to the outer frame portion so as to overlap the step.
At least one of the one main surface and the other main surface is formed so that at least a part of the step of the portion overlapping the lead-out wiring is not parallel to the X axis in plan view. Crystal diaphragm. The crystal diaphragm according to claim 1,
At least a part of the step of the portion overlapping with the lead-out wiring is formed as a straight portion that is not parallel to the X axis in plan view. The crystal diaphragm according to claim 2,
The quartz crystal diaphragm, wherein the linear portion is orthogonal to the X axis in plan view. The crystal diaphragm according to claim 2 or 3,
The length of the straight part is at least half of the line width of the lead-out wiring. The crystal diaphragm according to claim 4,
The length of the straight portion is equal to or greater than the line width of the lead-out wiring. The quartz crystal diaphragm according to any one of claims 1 to 5,
The step is formed on the outer frame part side of the boundary between the holding part and the outer frame part. The quartz crystal diaphragm according to any one of claims 1 to 6,
In at least one of the one main surface and the other main surface, the etching region has a entering portion formed so as to enter a part of the outer frame portion from the holding portion, and the etching region in the entering portion. The boundary line is the step,
The crystal vibration plate, wherein a starting point on the −X side of the step is formed inside a connection area between the holding portion and the outer frame portion. A quartz crystal diaphragm according to any one of claims 1 to 7;
A first sealing member that covers the one principal surface of the crystal diaphragm;
A crystal vibrating device, comprising: a second sealing member that covers the other main surface of the crystal vibrating plate.

Images