JP6794938B2 - Crystal diaphragm and crystal vibration device - Google Patents

Description

In the present invention, the vibrating portion in which the exciting electrode is formed, the outer frame portion arranged around the vibrating portion, and the holding portion that connects and holds the vibrating portion to the outer frame portion are an AT-cut type crystal plate. The present invention relates to a crystal vibrating plate integrally formed with, and a crystal vibrating device provided with the crystal vibrating plate.

In recent years, the operating frequencies of various electronic devices have been increased and the packages have been made smaller (particularly lower in height). Therefore, as the frequency increases and the package becomes smaller, the crystal vibration device (for example, a crystal oscillator, a crystal oscillator, etc.) is also required to have a higher frequency and a smaller package.

A so-called sandwich-structured crystal vibration device is known as a crystal vibration device suitable for miniaturization and reduction in height. The sandwich-structured crystal vibration device has a substantially rectangular parallelepiped package. This package is composed of, for example, a first sealing member and a second sealing member made of glass or quartz, and a crystal diaphragm having excitation electrodes formed on both main surfaces, and the first sealing member and the second sealing member. The stop members are laminated and joined via a crystal diaphragm. Then, the vibrating portion of the crystal diaphragm arranged inside the package (internal space) is hermetically sealed by the first sealing member and the second sealing member.

The crystal diaphragm used in a crystal vibrating device having a sandwich structure holds a vibrating portion in which an exciting electrode is formed, an outer frame portion arranged around the vibrating portion, and the vibrating portion connected to the outer frame portion. The holding portion is integrally formed on the crystal plate. The AT-cut type crystal plate, which is easy to process and has excellent frequency and temperature characteristics, is most widely used as this crystal diaphragm.

In a crystal diaphragm in which a vibrating portion, an outer frame portion, and a holding portion are integrally formed, there arises a problem of vibration leakage such that piezoelectric vibration generated in the vibrating portion easily leaks to the outer frame portion via the holding portion. 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 the holding portion is formed so as to protrude from the vibrating portion in the Z'axis direction of the AT cut. Here, the crystal axes of the artificial quartz are the X-axis, the Y-axis, and the Z-axis, and the Y-axis and the Z-axis of the AT-cut quartz crystal rotated by 35 ° 15'around the X-axis are the Y'axis, respectively. Let it be the Z'axis.

It is known that in the AT-cut type crystal diaphragm, 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 vibrating portion. In the configuration of Patent Document 1, the holding portion holds the vibrating portion along the Z'axis direction in which the displacement of the piezoelectric vibration is small. Therefore, when the crystal diaphragm is piezoelectrically vibrated, the piezoelectric vibration is less likely to leak through the holding portion, and the vibrating portion can be efficiently piezoelectrically vibrated.

International Publication No. 2016/121182

While the crystal diaphragm disclosed in Patent Document 1 has a configuration suitable for suppressing vibration leakage from the vibrating portion, there arises a problem that problems such as disconnection are likely to occur in the lead-out electrode of the excitation electrode. This issue will be described below.

The quartz diaphragm is manufactured by forming the outer shape of the quartz plate by an etching process and then forming electrodes and wiring on both main surfaces of the quartz plate. In the above-mentioned etching step, at least two etching processes of outer shape forming etching and frequency adjustment etching are performed on the rectangular crystal plate. Further, when the mesa structure is formed in the center of the vibrating portion, the mesa forming etching may be additionally performed.

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

When frequency adjustment etching is applied to the regions of the vibrating portion and the holding portion, a step is formed at the boundary between the holding portion and the outer frame portion due to the difference in thickness of the crystal plate. 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. Further, when the step is formed so as to be displaced toward the holding portion side, a gouged cross section may be formed in a part of the step. The gouged shape here means that the side surface of the step is further inclined from the vertical, and the angle formed by the side surface of the step and the main surface (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 crystal diaphragm, the lead wiring connected to the excitation electrode formed in the vibrating portion is formed to the outer frame portion via the holding portion, so that the lead wiring is formed at the boundary between the holding portion and the outer frame portion. It is necessary to cross the step part. Further, the lead 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 the metal film thickness by sputtering, and the lead wiring is likely to be broken. .. Alternatively, even if the wire is not broken, there is a risk that the resistance of the lead wiring will increase due to the thinning of the wiring. Increasing the resistance of the lead wire in the excitation electrode adversely affects the vibration characteristics of the crystal vibration device. Further, when a gouged cross section is formed on the step, the problem becomes more remarkable.

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

In order to solve the above problems, the crystal vibrating plate of the present invention has a substantially rectangular shape provided with a first excitation electrode formed on one main surface and a second excitation electrode formed on the other main surface. An outer frame that protrudes from the vibrating portion and the corner portion of the vibrating portion in the Z'axis direction of the AT cut to hold the vibrating portion, and surrounds the outer periphery of the vibrating portion and holds the holding portion. It is an AT-cut type crystal vibrating plate having a portion, and the boundary between the holding portion and the outer frame portion is on a side of the inner periphery of the outer frame portion parallel to the X axis. In this case, at least a part of the vibrating portion and the holding portion is an etching region having a thickness thinner than that of the outer frame portion, and the etching region causes the holding portion and the outer frame portion to be separated from each other. A step is formed in the vicinity of the boundary, and 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 characterized in that at least a part of the step of the portion overlapping with the lead wiring is formed so as not to be parallel to the X axis in a plan view. ..

In the etching region for making the thickness of the holding portion thinner than that of the outer frame portion, a step is formed at the boundary of the etching region due to the difference in the thickness of the quartz plate. This step has a vertical cross section (in some cases, a gouged cross section) 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 a plan view is formed at least a part of the step of the portion that overlaps with the lead-out wiring. Since a gentle step can be formed in this portion, it is possible to suppress disconnection of the lead wiring on the step.

Further, in the crystal diaphragm, at least a part of the step of the portion overlapping with the lead-out wiring can be formed as a straight portion not parallel to the X axis in a plan view.

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

Further, in the crystal diaphragm, the straight line portion may be configured to be orthogonal to the X axis in a plan view.

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

Further, in the crystal diaphragm, the length of the straight line portion may be a half or more of the line width of the leader wiring. Alternatively, in the crystal diaphragm, the length of the straight line portion may be equal to or larger than the line width of the leader wiring.

According to the above configuration, by making the straight portion longer than the line width of the lead wiring, it is possible to more effectively suppress the disconnection of the lead wiring and the like.

Further, in the crystal diaphragm, the step may be formed on the outer frame portion side of the boundary between the holding portion and the outer frame portion.

According to the above configuration, the strength of the holding portion can be improved, and it is possible to prevent a gouged cross section from being generated at the step.

Further, in the crystal diaphragm, on 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 entrance 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. Can be.

According to the above configuration, the area of the intruding portion is suppressed, so that the joint area of the outer frame portion with the sealing member can be secured. As a result, it is possible to suppress a decrease in bonding strength and sealing property in the crystal vibration device.

Further, in order to solve the above-mentioned problems, the crystal vibration device of the present invention comprises the above-mentioned crystal diaphragm, a first sealing member covering the one main surface of the crystal diaphragm, and the crystal diaphragm. It is characterized in that it is provided with a second sealing member that covers the other main surface.

In the crystal diaphragm and the crystal vibration device of the present invention, a gentle step portion is formed at the boundary of the etching region near the connection portion between the outer frame portion and the holding portion, and the excitation electrode is formed so as to cross the gentle step portion. By forming the lead-out wiring, it is possible to prevent the wiring from being broken or the resistance to be increased on the step generated at the boundary of the etching region.

It is a schematic block diagram which shows typically each structure of the crystal oscillator which concerns on this embodiment. FIG. 2 is a schematic plan view of the first sealing member of the crystal oscillator on the first main surface side. FIG. 3 is a schematic plan view of the first sealing member of the crystal oscillator on the second main surface side. FIG. 4 is a schematic plan view of the crystal diaphragm of the crystal oscillator on the first main surface side. FIG. 5 is a schematic plan view of the crystal diaphragm of the crystal oscillator on the second main surface side. FIG. 6 is a schematic plan view of the second sealing member of the crystal oscillator on the first main surface side. FIG. 7 is a schematic plan view of the second sealing member of the crystal oscillator on the second main surface side. It is a figure which shows the state immediately after etching process to a crystal plate in a crystal diaphragm, (a) is the schematic plan view of the 1st main surface side, (b) is the schematic plan view of the 2nd main surface side. Is. It is an enlarged view which shows the vicinity of the connection part of the holding part and the outer frame part in a crystal diaphragm, (a) is the schematic plan view of the 1st main surface side, (b), (c) are the 1st main surface side. Schematic cross-sectional view, (d) is a schematic cross-sectional view on the second main surface side. It is an enlarged view which shows the vicinity of the connection part of the holding part and the outer frame part in a crystal diaphragm, and is the schematic plan view which shows the shape of the etching region and the lead-out wiring. It is an enlarged view which shows the vicinity of the connection part of the holding part and the outer frame part in a crystal diaphragm, and (a) and (b) are schematic plan views which show the deformation example of the shape of the etching region and the lead-out wiring. It is an enlarged view which shows the vicinity of the connection part of the holding part and the outer frame part in a crystal diaphragm, and (a) and (b) are schematic plan views which show the deformation example of the shape of the etching region and the lead-out wiring. It is an enlarged view which shows the vicinity of the connection part of the holding part and the outer frame part in a crystal diaphragm, and is the schematic plan view which shows the modification of the shape of the etching region and the lead-out wiring.

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

-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 the crystal oscillator 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 package 12 having a substantially rectangular sandwich structure. It is composed. Further, the IC chip 5 is mounted on the main surface of the first sealing member 3 on the side opposite to the joint 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 a crystal vibration plate 2.

In the crystal diaphragm 2, the first excitation electrode 221 is formed on the first main surface 211 which is one main surface, and the second excitation electrode 222 is formed on the second main surface 212 which is the other main surface. Then, in the crystal oscillator 101, the first sealing member 3 and the second sealing member 4 are joined to both main surfaces (first main surface 211 and second main surface 212) of the crystal diaphragm 2. The 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, for example, a package size of 1.0 × 0.8 mm, and is designed to be compact and low in height. Further, with the miniaturization, in the package 12, the electrodes are made conductive by using the through holes described later without forming the casters.

Next, each member of the crystal diaphragm 2, the first sealing member 3, and the second sealing member 4 in the crystal oscillator 101 described above will be described with reference to FIGS. 1 to 7. In addition, here, each member which is configured as a single unit which is not joined will be described.

As shown in FIGS. 4 and 5, the crystal diaphragm 2 is a piezoelectric substrate made of quartz, and both main surfaces (first main surface 211 and second main surface 212) are flat smooth surfaces (mirror surface processing). It is formed. In the present embodiment, as the crystal diaphragm 2, an AT-cut quartz plate that performs thickness sliding vibration is used. 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 lateral direction (short side direction) of the crystal vibrating plate 2 is the X-axis direction, and the direction parallel to the longitudinal direction (long side direction) of the crystal vibrating plate 2 is the Z'axis. It is said to be the direction. The AT cut is 35 ° around the X axis with respect to the Z axis among the three crystal axes of the artificial quartz, the electric axis (X axis), the mechanical axis (Y axis), and the optical axis (Z axis). This is a processing method that cuts out at an angle tilted by 15'. In the AT-cut quartz plate, the X-axis coincides with the crystal axis of the quartz. The Y'axis and Z'axis correspond to axes tilted 35 ° 15'from the Y and Z axes of the quartz crystal axis, respectively. The Y'axis direction and the Z'axis direction correspond to the cutting direction when cutting out the AT-cut quartz plate.

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

In the present embodiment, the holding portion 24 is provided only at one location between the vibrating portion 22 and the outer frame portion 23. Further, 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 such a difference in thickness between the outer frame portion 23 and the holding portion 24, the natural frequencies of the piezoelectric vibrations of the outer frame portion 23 and the holding portion 24 differ, and the piezoelectric vibration of the holding portion 24 causes the outer frame portion 23 to differ. Is less likely to resonate. The formation location of the holding portion 24 is not limited to one, and the holding portion 24 is formed at two locations between the vibrating portion 22 and the outer frame portion 23 (for example, both sides in the −Z ′ axial direction). It may be provided in.

The holding portion 24 extends (projects) from only one corner portion of the vibrating portion 22 located in the + X direction and the −Z ′ direction to the outer frame portion 23 in the −Z ′ direction. As described above, since the holding portion 24 is provided at the corner portion of the outer peripheral end portion of the vibrating portion 22 in which the displacement of the piezoelectric vibration is relatively small, the holding portion 24 is provided at a portion other than the corner portion (center portion of the side). It is possible to suppress the leakage of the piezoelectric vibration to the outer frame portion 23 via the holding portion 24, and it is possible to vibrate the vibrating portion 22 more efficiently as compared with the case where the vibration portion 22 is provided. Further, as compared with the case where two or more holding portions 24 are provided, the stress acting on the vibrating portion 22 can be reduced, and the frequency shift of the piezoelectric vibration caused by such stress is reduced to stabilize the piezoelectric vibration. The sex can be improved.

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

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

Further, 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 provided in the regions of the four corners (corners) of the outer frame portion 23, respectively. The second through hole 262 is an outer frame portion 23, and is provided on one side of the vibrating portion 22 in the Z'axis direction (in FIGS. 4 and 5, the + Z'direction side). A connection pattern 253 is formed around the first through hole 261. Further, around the second through hole 262, a connection joint pattern 254 is formed on the first main surface 211 side, and a connection joint 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 surface of each of the through holes. It 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 and the second excitation electrode 222, the first lead-out wiring 223, the second lead-out wiring 224, the first joint pattern 251 and the vibration side second joint pattern 252, and the connection joint pattern 253 , 254, 27, 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 a physical vapor phase growth on the base film. It can be formed from a bonded film. In this embodiment, Ti (or Cr) is used as the base film, and Au is used as the bonding film.

As shown in FIGS. 2 and 3, the first sealing member 3 is a rectangular parallelepiped substrate formed from one glass wafer, and the second main surface 312 (crystal diaphragm 2) of the first sealing member 3 is The surface to be joined to) is formed as a flat smooth surface (mirror surface processing).

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

As shown in FIGS. 2 and 3, the first sealing member 3 has six through holes connected to each of the six electrode patterns 37 and 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 regions of the four corners (corners) of the first sealing member 3. The fourth and fifth through holes 323 and 324 are provided in the A2 direction and the A1 direction of FIGS. 2 and 3, respectively. The A1 and A2 directions in FIGS. 2, 3, 6 and 7 correspond to the −Z ′ direction and the + Z ′ direction in FIGS. 4 and 5, respectively, and the B1 and B2 directions in FIGS. It corresponds to the −X direction and the + X direction in FIGS. 4 and 5, respectively.

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 each of the through holes. It is formed along the inner wall surface. Further, the central portion of each of the third through hole 322 and the fourth and fifth through holes 323 and 324 is a hollow through portion penetrating 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 joining pattern 321 is formed as a sealing-side first sealing portion for joining to the crystal diaphragm 2. The first bonding pattern 321 on the sealing side is formed in an annular shape in a plan view.

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

In the first sealing member 3, the sealing-side first joining pattern 321 and the connecting joining patterns 34, 3513 to 353, and the wiring pattern 33 can be formed by the same process. Specifically, these are formed by laminating a base film formed by physical vapor deposition on the second main surface 312 of the first sealing member 3 and a physical vapor phase growth on the base film. It can be formed from the bonded film. In this embodiment, Ti (or Cr) is used as the base film, and Au is used as the bonding film.

As shown in FIGS. 6 and 7, the second sealing member 4 is a rectangular parallelepiped substrate formed from one glass wafer, and the first main surface 411 (crystal diaphragm 2) of the second sealing member 4 is The surface to be joined to) is formed as a flat smooth surface (mirror surface processing).

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

The second main surface 412 (outer main surface not facing the crystal diaphragm 2) of the second sealing member 4 is provided with four external electrode terminals 43 that are electrically connected to the outside. The external electrode terminals 43 are located at the four corners (corners) of the second sealing member 4.

As shown in FIGS. 6 and 7, the second sealing member 4 is formed with 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 the regions of the four corners (corners) of the second sealing member 4. In the sixth through hole 44, through electrodes for conducting conduction of the electrodes formed on the first main surface 411 and the second main surface 412 are formed along the inner wall surface of each of the through holes. Further, the central portion of each of the sixth through holes 44 is 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, a connection pattern 45 is formed around the sixth through hole 44, respectively.

In the second sealing member 4, the sealing-side second joining pattern 421 and the connecting joining pattern 45 can be formed by the same process. Specifically, these are laminated with a base film formed by physical vapor deposition on the first main surface 411 of the second sealing member 4 and physically vapor-deposited on the base film. It can be formed from the bonded film. In this embodiment, Ti (or Cr) is used as the base film, and Au is used as the bonding film.

In the crystal oscillator 101 including the crystal diaphragm 2, the first sealing member 3, and the second sealing member 4, the crystal diaphragm 2 and the first sealing member 3 are sealed with the vibration side first bonding pattern 251. The first bonding pattern 321 on the stop side was overlapped and diffusion-bonded, and the crystal diaphragm 2 and the second sealing member 4 overlapped the second bonding pattern 252 on the vibrating side and the second bonding pattern 421 on the sealing side. 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 vibrating portion 22 is hermetically sealed.

At this time, the connection patterns described above are also diffusion-bonded in a superposed state. Then, by joining the connection patterns to each other, the crystal oscillator 101 can obtain electrical conduction between the first excitation electrode 221 and the second excitation electrode 222, the IC chip 5, and the external electrode terminal 43.

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

The above is the basic structure of the crystal oscillator 101 according to the present embodiment, but the feature in the present invention is the shape of the stepped portion caused 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-out wiring formed in the stepped portion. From this, this feature point will be described in detail.

FIG. 8 is a diagram showing a state of the crystal diaphragm 2 immediately after the etching step on the crystal plate is performed (before the electrodes and wiring are formed), and FIG. 8A is a view on the first main surface 211 side. The plan view, (b) is a plan view on the second main surface 212 side. In the example shown in FIG. 8, a 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 forming etching and frequency adjustment etching. It shall be.

In the outer shape forming etching, a cutout portion is formed in a rectangular crystal plate to form the outer shape of the vibrating portion 22, the outer frame portion 23, and the holding portion 24. Further, a through hole in the crystal diaphragm 2 is also formed by the outer shape forming etching.

The frequency adjustment etching is an etching step of adjusting the thickness of the vibrating portion 22 and the holding portion 24 in order to set the oscillating frequency of the crystal vibrating device to a predetermined value. In FIG. 8, the etching region Eg by frequency adjustment etching is shown by diagonal hatching. The etching region Eg includes at least a part of the vibrating portion 22 and the holding portion 24, and is thinner than the outer frame portion 23.

A step is formed at the boundary of the etching region Eg due to the difference in thickness of the quartz plate. At this time, if the boundary line to be a step is parallel to the X-axis, this step becomes 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. However, as described above, the shape is such that the angle formed by 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. Further, as described above, if the lead-out wiring from the excitation electrode is formed so as to exceed such a step in a vertical cross section or a step having a gouged shape, disconnection is likely to occur in this lead-out wiring.

Then, in the present embodiment, the holding portion 24 extends from only one corner portion of the vibrating portion 22 located in the + X direction and the −Z ′ direction to the outer frame portion 23 in the −Z ′ direction (). (Protruding). In this case, the boundary between the holding portion 24 and the outer frame portion 23 exists on a side of the inner periphery of the outer frame portion that is parallel to the X axis. 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 (see FIG. 9A). (See FIG. 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 the 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 means a shape in which the side surface of the step is inclined and the angle formed by the side surface of the step and the main surface (main surface of the holding portion or the main surface of the outer frame portion) is obtuse. Point.

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 in the lead wiring from the excitation electrode. However, since it is only one main surface of the quartz plate (here, the first main surface 211) that requires such a device, 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).

In the first main surface 211 of the crystal diaphragm 2 to which the disconnection suppressing measure, which is a feature of the present invention, is taken, as shown in FIG. 10, the boundary of the etching region Eg is defined as the boundary between the holding portion 24 and the outer frame portion 23. 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 without being aligned. In this case, the step generated at the boundary line L1 does not become a step having a vertical cross section or a gouged shape, but becomes a gentle step. The first lead-out wiring 223 formed on the first main surface 211 is formed so as to cross at least a part of the boundary line L1.

As a result, 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 a plan view. Of the steps that overlap with the first lead-out wiring 223, the first lead-out wiring 223 is formed on the gentle steps in the portion that is not parallel to the X-axis, so that the wiring film thickness is sufficient in this portion. It can be secured, and disconnection of the first lead-out wiring 223 and high resistance can be suppressed.

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 can be considered. Some modifications of the boundary shape of the etching region Eg are shown in FIGS. 11 (a), 11 (b), 12 (a), 12 (b) and 13.

In the example shown in FIG. 10, the boundary of the etching region Eg includes not all the boundary line L1 that is not parallel to the X-axis, but a boundary line L2 that is partially parallel to the X-axis. However, as shown in FIGS. 11 (a), 11 (b) and 13, all the boundaries of the etching region Eg may be boundary lines L1 that are 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. 11 (a), and FIGS. 11 (b), 12 (a), and (b). ) And as shown in FIG. 13, it may be a straight line in a plan view. 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 with the first leader wiring 223 is the first leader wiring 223 on the step. It is preferably formed as a straight portion in order to more effectively suppress disconnection and the like.

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

When a straight line portion is provided on the step overlapping with the first lead-out wiring 223, the length W1 of the straight line portion is preferably half or more of the line width W2 of the first lead-out wiring 223 (see FIG. 12B). ). Further, when a straight line portion is provided on the step overlapping with the first lead-out wiring 223, the length of the straight line portion is preferably equal to or longer than the line width of the first lead-out wiring 223 (FIGS. 11B and 12). a) See). That is, the longer the length of the straight line portion with respect to the line width of the first leader wiring 223, the more effectively the disconnection of the first leader wiring 223 and the like can be suppressed.

Further, in the examples of FIGS. 10, 11 (a) and 11 (b) and FIGS. 12 (a) and 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 on the holding portion 24 side of the boundary between the holding portion 24 and the outer frame portion 23. May be good. However, when a step is formed on the holding portion 24 side, the above-mentioned hollow-shaped cross section is likely to occur at the boundary on the + X side at the step. Therefore, in order to prevent this, the boundary of the etching region Eg is set. 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 on the outer frame portion 23 side of 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 etching portion to be formed. Then, as shown in FIG. 10, the start point P on the −X side in this entry portion can be formed inside the connection area R between the holding portion 24 and the outer frame portion 23. In this configuration, the area of the intruding portion is suppressed, so that the joint area of the outer frame portion 23 with the sealing member (first sealing member 3, second sealing member 4) can be secured. As a result, it is possible to suppress a decrease in bonding strength and sealing property in the crystal vibration device (for example, the crystal oscillator 101).

Further, when the intrusion portion is formed in the outer frame portion 23, if the starting point P is formed on the extension line of the −X side side of the holding portion 24, the holding portion 24 and the outside are formed during frequency adjustment etching. It has been found by the inventor of the present application that a dent is generated at the connection portion with the frame portion 23. When such a dent is generated, 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 crystal vibration device is lowered. As shown in FIG. 10, in the configuration in which the start point P is formed inside the connection area R between the holding portion 24 and the outer frame portion 23, the occurrence of the dent can be avoided, and as a result, the impact resistance of the crystal vibration device is improved. It can prevent the decrease.

The embodiments disclosed this time are exemplary in all respects and do not provide a basis for limited interpretation. Therefore, the technical scope of the present invention is not construed solely by the above-described embodiments, but is defined based on the description of the claims. It also includes all changes within the meaning and scope of the claims.

2 Crystal diaphragm 3 1st sealing member 4 2nd sealing member 5 IC chip 12 Package 22 Vibrating part 23 Outer frame part 24 Holding part 101 Crystal oscillator (crystal oscillator)
211 1st main surface 212 2nd main surface 221 1st excitation electrode 222 2nd excitation electrode 223 1st lead-out wiring 224 2nd lead-out wiring Eg Etching region L1 Boundary line not parallel to X-axis

Claims (6)

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 portion that protrudes from the corner portion of the vibrating portion in the Z'axis direction of the AT cut and holds the vibrating portion, and a holding portion.
An AT-cut type crystal diaphragm having an outer frame portion that surrounds the outer circumference of the vibrating portion and holds the holding portion.
When the boundary between the holding portion and the outer frame portion is on a side of the inner periphery of the outer frame portion parallel to the X axis.
At least a part of the vibrating portion and the holding portion is an etching region having a thickness thinner than that of the outer frame portion, and the etching region brings an etching region near the boundary between the holding portion and the outer frame portion. A step is formed,
The lead wiring of the first excitation electrode and the second excitation electrode is 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 with the lead wiring is not parallel to the X axis in a plan view .
At least a part of the step of the portion that overlaps with the lead wiring is formed as a straight portion that is not parallel to the X axis in a plan view.
A crystal diaphragm characterized in that the length of the straight portion is equal to or larger than the line width of the lead-out wiring . The crystal diaphragm according to claim 1 .
The straight line portion is a crystal diaphragm characterized in that it is orthogonal to the X axis in a plan view. The crystal diaphragm according to claim 1 or 2 .
A crystal diaphragm characterized in that the step is formed on the outer frame portion side of the boundary between the holding portion and the outer frame portion. The crystal diaphragm according to any one of claims 1 to 3 .
On at least one of the one main surface and the other main surface, the etching region has a penetration portion formed by entering a part of the outer frame portion from the holding portion, and the etching region in the penetration portion. The boundary line of is the step.
A crystal diaphragm characterized in that 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 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 portion that protrudes from the corner portion of the vibrating portion in the Z'axis direction of the AT cut and holds the vibrating portion, and a holding portion.
An AT-cut type crystal diaphragm having an outer frame portion that surrounds the outer circumference of the vibrating portion and holds the holding portion.
When the boundary between the holding portion and the outer frame portion is on a side of the inner periphery of the outer frame portion parallel to the X axis.
At least a part of the vibrating portion and the holding portion is an etching region having a thickness thinner than that of the outer frame portion, and the etching region brings an etching region near the boundary between the holding portion and the outer frame portion. A step is formed,
The lead wiring of the first excitation electrode and the second excitation electrode is 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 with the lead wiring is not parallel to the X axis in a plan view.
At least a part of the step of the portion that overlaps with the lead wiring is formed as a straight portion that is not parallel to the X axis in a plan view.
A crystal diaphragm characterized in that the lead-out wiring is formed so as to straddle the plurality of straight portions. The crystal diaphragm according to any one of claims 1 to 5 .
A first sealing member that covers the one main surface of the crystal diaphragm,
A crystal vibration device including a second sealing member that covers the other main surface of the crystal diaphragm.

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