JP2014179773A - Crystal oscillator piece, method of manufacturing crystal oscillator piece, and crystal oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystal oscillator piece in which the oscillation energy can be confined accurately in the central part thereof, regardless of the structure of a natural crystal plane, in an AT cut crystal oscillator piece, and to provide a manufacturing method therefor, and a crystal oscillator using the crystal oscillator piece.SOLUTION: A crystal oscillator piece formed by AT cut has a pair of principal surfaces provided to face each other, a side surface crossing the principal surfaces and formed as a natural crystal plane, and a slope connecting the principal surfaces and the side surface, and formed with a smaller inclination angle than the natural crystal plane for the principal surfaces.

Description

  The present invention relates to a crystal resonator element, a method for manufacturing a crystal oscillator, and a crystal resonator.

  In a crystal resonator element formed by AT-cut, a structure that reduces the thickness of the end part and attenuates the vibration transmitted to the end part is known in order to confine the vibration energy caused by the thickness shear vibration in the center part of the resonator element. (See Patent Document 1).

JP 2008-67345 A

  In order to reduce the thickness of the end portion of the crystal vibrating piece, a slope is formed at the end portion of the crystal vibrating piece by wet etching. At this time, since the AT-cut quartz crystal vibrating piece has crystal anisotropy, the slope formed by wet etching becomes a natural crystal plane having a specific tilt angle. However, since the natural crystal plane has a somewhat large tilt angle, vibration transmitted without sufficient attenuation oscillates at the boundary between the main surface of the quartz crystal vibrating piece and the slope that is the natural crystal plane, and vibration energy In some cases, it is difficult to sufficiently confine the crystal in the center of the quartz crystal vibrating piece.

  The present invention has been made in view of such circumstances, and the object of the present invention is to accurately confine the vibration energy in the central portion of the quartz crystal vibrating piece regardless of the structure of the natural crystal plane in the AT cut quartz crystal vibrating piece. A quartz crystal resonator element that can be produced and a method of manufacturing the same. Another object of the present invention is to provide a crystal resonator using the crystal resonator element.

  The quartz crystal resonator element of the present invention is a quartz crystal resonator element formed by AT-cut, a pair of opposing main surfaces, a side surface that intersects the main surface and is formed as a natural crystal plane, A main surface and the side surface, and an inclined surface formed with an inclination angle smaller than the natural crystal plane with respect to the main surface.

  According to this configuration, the inclination angle of the slope connecting the main surface and the side surface with respect to the main surface is smaller than that of the natural crystal plane. For this reason, it is possible to suppress the vibration from oscillating at the boundary between the main surface and the inclined surface, and to attenuate the vibration transmitted to the end. Therefore, it is possible to improve the accuracy of confining the vibration energy in the center part of the crystal vibrating piece.

The slope may be formed at a position corresponding to two opposing sides of at least one of the main surfaces.
According to this configuration, it is possible to attenuate the vibration transmitted from the central portion to both ends provided with the inclined surfaces, and to improve the accuracy of confinement of vibration energy.

The side surface may be a surface that intersects the X axis.
According to this configuration, a quartz crystal resonator element having a high bending vibration suppressing effect can be obtained.

The side surface may be a surface that intersects the Z ′ axis.
According to this configuration, it is possible to obtain a quartz crystal resonator element having a high effect of suppressing contour vibration.

The main surface may be a quadrangle, and the slope may be formed at positions corresponding to at least four sides of the main surface.
According to this configuration, it is possible to obtain a quartz crystal resonator element with excellent vibration energy confinement accuracy.

The inclined surface may be formed at a position corresponding to a side of the main surface on one side and the main surface on the other side.
According to this configuration, it is possible to obtain a quartz crystal resonator element with excellent vibration energy confinement accuracy.

The inclination angle may be 20 ° or less.
According to this configuration, it is possible to obtain a quartz crystal resonator element with excellent vibration energy confinement accuracy.

The slope may have a center line average roughness of 0.2 nm or more and 10 nm or less.
According to this configuration, since the surface roughness is low, the impedance of the crystal vibrating piece can be reduced.

The crystal resonator of the present invention includes the crystal resonator element of the present invention.
According to this configuration, since the quartz crystal resonator element described above is provided, a quartz resonator having excellent performance can be obtained.

  The method for manufacturing a quartz crystal vibrating piece according to the present invention is a method for manufacturing a quartz crystal vibrating piece formed by AT-cut, and includes a step of dry etching at least one surface of both surfaces of a wafer and the dry etching surface. A step of forming an external pattern mask of the crystal vibrating piece, a step of forming a slope on the dry-etched surface of the wafer by wet etching, a step of removing the mask, and an external shape of the wafer. And dividing into pieces along the pattern.

  According to this method, after at least one of the one surface and the other surface of the wafer is dry-etched, a mask of the external pattern of the crystal vibrating piece is formed, and wet etching is performed to form a slope on the surface of the wafer. To do. As a result, a slope having a gentle slope is formed on the dry-etched wafer surface without depending on the slope of the natural crystal plane. Therefore, by dividing the wafer into individual pieces along the outer shape pattern, it is possible to manufacture a crystal vibrating piece having a slope that is gentler than the natural crystal plane.

In the step of dividing into pieces, a natural crystal plane may be formed by wet etching.
According to this method, a crystal resonator element having a natural crystal plane and a slope that is gentler than the natural crystal plane can be obtained.

  According to the quartz crystal resonator element of the present invention, the end portion is provided with the inclined surface whose inclination angle is gentler than that of the natural crystal plane, so that the vibration energy is accurately applied to the center part of the crystal resonator element regardless of the structure of the natural crystal plane. Can be confined.

It is a disassembled perspective view which shows embodiment of a crystal oscillator. FIG. 3 is a perspective view of a rough Lumbard stone for explaining a cutting angle of a quartz plate and a coordinate axis of a quartz crystal. It is a figure which shows 1st Embodiment, Comprising: (a) is a front view, (b) is a top view, (c) is a side view. It is a flowchart which shows the manufacturing process of the quartz crystal vibrating piece of 1st Embodiment. It is sectional drawing and a top view which show the procedure of the manufacturing process of the quartz crystal vibrating piece of 1st Embodiment. It is sectional drawing and a top view which show the procedure of the manufacturing process of the quartz crystal vibrating piece of 1st Embodiment. It is a figure explaining the effect of the crystal vibrating piece of 1st Embodiment. It is a figure which shows the modification of 1st Embodiment, Comprising: (a) is a front view, (b) is a top view, (c) is a side view. It is a figure which shows 2nd Embodiment, Comprising: (a) is a front view, (b) is a top view, (c) is a side view. It is a figure which shows 3rd Embodiment, Comprising: (a) is a front view, (b) is a top view, (c) is a side view. It is a figure which shows 4th Embodiment, (a) is a front view, (b) is a top view, (c) is a side view. It is a figure which shows 5th Embodiment, Comprising: (a) is a front view, (b) is a top view, (c) is a side view. It is a figure which shows 6th Embodiment, Comprising: (a) is a front view, (b) is a top view, (c) is a side view.

Hereinafter, a crystal resonator element, a method for manufacturing a crystal resonator element, and a crystal resonator according to an embodiment of the present invention will be described with reference to the drawings.
The scope of the present invention is not limited to the following embodiment, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each structure easy to understand, the actual structure may be different from the scale, number, or the like in each structure.

[First Embodiment]
FIG. 1 is an exploded perspective view showing the crystal resonator of the present embodiment.
As shown in FIG. 1, the crystal resonator 1 according to the present embodiment is formed in a box shape in which a base substrate 2 and a lid substrate 3 are laminated in two layers. Is mounted.
The crystal vibrating piece 4 includes a crystal vibrating plate 10 and a pair of electrode films 20 formed on the front and back main surfaces of the crystal vibrating plate 10, respectively.

As shown in FIG. 2, the quartz diaphragm 10 is formed by AT-cutting the quartz lambard ore 6 in which the coordinate axes of the quartz crystal are defined by the X axis, the Y axis, and the Z axis (the front and back main surfaces are rotated from the Z axis around the X axis). The quartz plate 7 obtained by cutting the lens so as to have an angle of about 35 degrees 15 minutes in the counterclockwise direction is formed into a rectangular shape in plan view by wet etching after that.
FIG. 2 is a perspective view of the lumbar raw stone 6 for explaining the cutting angle of the quartz plate 7 and the coordinate axes of the quartz crystal. Further, in the present embodiment, the Z ′ axis is a crystal axis in a direction orthogonal to the X axis on the front and back main surfaces of the crystal diaphragm 10 as shown in FIG. 1, and the Y ′ axis is the X axis and the Z axis. 'A crystal axis perpendicular to the axis.

3A and 3B are diagrams showing the crystal vibrating piece 4, in which FIG. 3A is a front view, FIG. 3B is a plan view, and FIG. 3C is a side view.
As shown in FIG. 3, the crystal diaphragm 10 is a substantially rectangular parallelepiped. At both ends in the short side direction (Z′-axis direction) of the main surface 10a of the quartz crystal plate 10, inclined surfaces 11a are formed so as to connect the main surface 10a and the side surface 11b that is a natural crystal surface. ing. The side surface 11b is substantially perpendicular to the front and back main surfaces 10a and 10b, and the inclined surface 11a is inclined at an angle θ1 with respect to the front main surface 10a over the entire length of the long side of the front main surface 10a.

  The angle θ1 of the inclined surface 11a is smaller than the value of the angle formed by the natural crystal plane and the main surface of the quartz crystal vibrating piece, for example, 20 ° or less. As the dimension of the slope 11a, for example, when the height h1 is 5 μm, the width w1 is 50 μm or more and 200 μm or less.

As shown in FIGS. 1 and 3, the pair of electrode films 20 each include an excitation electrode 21, an extraction electrode 22, and a mount electrode 23.
The excitation electrodes 21 are formed at substantially central portions of the front and back main surfaces 10a and 10b of the quartz crystal plate 10 so as to face each other with the crystal plate 10 interposed therebetween. Mount electrodes 23 are provided at both ends in the short side direction (Z′-axis direction) at one end (−X direction side) in the long side direction of the quartz crystal plate 10. The mount electrode 23 is formed from the front main surface 10a to the back main surface 10b via the slope 11a and the side surface 11b.

Of the mount electrodes 23, one mount electrode 23 is electrically connected to one excitation electrode 21 formed on the front main surface 10 a via the extraction electrode 22, and the other mount electrode 23 is the extraction electrode 22. Is electrically connected to the other excitation electrode 21 formed on the main surface 10b on the back side.
The electrode film 20 including the excitation electrode 21, the extraction electrode 22, and the mount electrode 23 described above is a single layer film such as gold, or a laminate in which a metal layer such as gold is stacked on a metal such as chromium as a base layer. It is formed of a film.

The quartz crystal vibrating piece 4 configured in this way is mounted on the upper surface 2a of the base substrate 2 as shown in FIG. 1 using mounting members such as bumps and conductive adhesive. More specifically, the pair of mount electrodes 23 formed on the back main surface 10b of the crystal diaphragm 10 are in contact with the inner electrode 300 formed on the upper surface 2a of the base substrate 2 via the mounting member. Mounted in state.
Thereby, the quartz crystal vibrating piece 4 is mechanically held on the upper surface 2a of the base substrate 2, and the inner electrode 300 and the mount electrode 23 are electrically connected to each other.

Next, with reference to FIGS. 4 to 6, a method for manufacturing the quartz crystal vibrating piece 4 will be described.
FIG. 4 is a flowchart showing a manufacturing process of the crystal vibrating piece 4.
FIG. 5 is a diagram showing a procedure of the manufacturing process of the crystal vibrating piece 4, and is a cross-sectional view and a plan view showing a procedure of a recess forming process S <b> 2 described later.
FIG. 6 is a diagram showing a procedure of the manufacturing process of the quartz crystal vibrating piece 4, and is a cross-sectional view and a plan view showing a procedure of an individualization process S 3 described later.

As shown in FIG. 4, the method for manufacturing a crystal vibrating piece according to the present embodiment includes a wafer preparation step S1, a concave portion forming step S2, an individualizing step S3, and an electrode forming step S4.
First, as shown in FIG. 4, a rough Lambert stone crystal is AT-cut and lapped to a constant thickness, and then rough-processed. Then, the work-affected layer is removed by etching, and then mirror polishing such as polishing is performed. To prepare a wafer S (see FIG. 5A) having a predetermined thickness (S1).

 The recess forming step S2 is a step of forming a later-described recess 42 on the surface of the wafer S.

First, as shown in FIG. 5A, the surface of the wafer S is dry-etched (S2a).
The dry etching is not particularly limited as long as the slope 11a can be formed in the step S2f of performing the slope etching process on the wafer S, which will be described later, on the surface of the wafer S. For example, reactive ion etching (RIE) or reverse sputtering can be selected.
By this step, the surface of the wafer S is flattened.

Next, as shown in FIG. 5B, an etching protection film 40 and a photoresist film 41 are respectively formed on both surfaces of the wafer S (S2b).
The etching protective film 40 is a laminated film in which, for example, an etching protective film in which chromium (Cr) is formed to several tens of nm and an etching protective film in which gold (Au) is formed to several tens of nm are sequentially laminated.

In this step S2b, first, an etching protective film 40 is sequentially formed on the front and back main surfaces of the wafer S by a sputtering method, a vapor deposition method, or the like.
Next, a resist material is applied on the etching protection film 40 by a spin coating method or the like to form a photoresist film 41.
As a resist material used in the present embodiment, a rubber negative resist mainly composed of cyclized rubber (for example, cyclized isoprene) is preferably used. The rubber negative resist is refined by dissolving cyclized rubber in an organic solvent, adding a bisazide photosensitizer, filtering, and removing impurities.

Next, the surface on one side (+ Y ′ direction side) of the wafer S on which the etching protective film 40 and the photoresist film 41 are formed is exposed and developed in a lump using a photomask on which an external pattern is formed. .
As a result, as shown in FIG. 5C, an outer pattern 41a is formed on one side of the photoresist film 41 (S2c).
The outer shape pattern 41 a has a shape that follows the outer shape of the crystal diaphragm 10.

Next, etching is performed using the photoresist film 41 on which the outer pattern 41a is formed as a mask, and the unmasked etching protection film 40 is selectively removed (S2d).
Next, the photoresist film 41 is removed after the etching process (S2e).
As a result, as shown in FIG. 5D, an outer pattern 40 a is formed on one side of the etching protection film 40.

For the etching process, a wet etching method in which the wafer S on which the etching protective film 40 and the photoresist film 41 are formed is immersed in a chemical solution can be used.
Specifically, for example, when the etching protection film 40 is made of gold (Au), it can be etched using iodine as a chemical solution.
This patterning is performed collectively for the number of the plurality of quartz crystal plates 10.

Next, the unmasked wafer S is selectively etched by a slope using the outer pattern 40a of the etching protective film 40 as a mask (S2f).
As a result, as shown in FIG. 5E, the lower portion of the mask is also etched from the exposed surface of the unmasked wafer S, and the inclined surface 11a intersects the main surface of the wafer S at a gentle angle. Is formed as a side surface.

Here, normally, in the etching of quartz, a natural crystal plane having a specific angle appears due to etching anisotropy peculiar to quartz. Moreover, it is hardly seen that etching progresses from the exposed surface not masked to the lower side (inside) of the mask.
On the other hand, in this embodiment, since the surface of the wafer S is dry-etched (S1) before the slope etching is performed, the etching proceeds to the lower side of the mask, and the angle of the natural crystal plane is reached. A slope having a gentle angle that does not depend can be formed.

Next, as shown in FIG. 5F, etching is performed to remove the etching protective film 40 (S2g).
Through the above steps, the recess forming step S2 is completed, and the wafer S in which the recesses 42 are formed is obtained.

  The singulation step S3 is a step of dividing the wafer S on which the concave portion 42 is formed into pieces and forming the crystal diaphragm 10.

  First, as shown in FIG. 6A, an etching protective film 50 and a photoresist film 51 are formed on both surfaces of the wafer S in the same manner as the film forming step S2b described above (S3a).

Next, the surface on one side (+ Y ′ direction side) of the wafer S on which the etching protective film 50 and the photoresist film 51 are formed is exposed and developed in a lump using a photomask on which an external pattern is formed. .
Thereby, as shown in FIG. 6B, an outer pattern 51a is formed on one side of the photoresist film 51 (S3b).
The outer shape pattern 51 a has a shape that follows the outer shape of the crystal diaphragm 10.

Next, etching is performed using the photoresist film 51 on which the outer pattern 51a is formed as a mask, and the unmasked etching protection film 50 is selectively removed (S3c).
Next, the photoresist film 51 is removed after the etching process (S3d).
As a result, an external pattern 50a is formed on one side of the etching protection film 50 as shown in FIG.

Next, the unmasked wafer S is selectively etched using the external pattern 50a of the etching protective film 50 as a mask (S3e).
As a result, as shown in FIG. 6D, the side surface 11b of the crystal diaphragm 10 which is a natural crystal plane is formed, and the wafer S is singulated.
Next, as shown in FIG. 6E, etching is performed to remove the etching protective film 50 (S3f).
Through the above steps, the singulation step S3 is completed, and the crystal diaphragm 10 in which the wafer S is singulated is manufactured.

  The electrode forming step S <b> 4 is a step of forming an electrode on the surface of the crystal vibrating plate 10. By this step, the electrode film 20 is formed on the surface of the quartz crystal plate 10.

  The quartz crystal vibrating piece 4 is manufactured by the processes from S1 to S4 described above.

  According to the crystal vibrating piece 4 of the present embodiment, the angle θ1 formed with the front main surface 10a of the inclined surface 11a is gentler than that of the natural crystal plane. Therefore, it is possible to suppress the vibration from oscillating at the boundary portion between the front main surface 10a and the inclined surface 11a, and to sufficiently attenuate the vibration transmitted to the end portion of the crystal vibrating piece 4. Accordingly, it is possible to improve the accuracy of confining vibration energy in the center portion of the crystal vibrating piece 4.

  Further, it is known that the quartz crystal vibrating piece has vibration modes such as bending vibration and contour sliding vibration in addition to thickness-shear vibration. When the influence of vibrations other than these thickness-shear vibrations (hereinafter referred to as unnecessary vibrations) is large, an activity dip occurs and the vibration characteristics of the quartz crystal vibrating piece become unstable.

  Thickness-sliding vibration depends on the thickness of the crystal vibrating piece, whereas many unnecessary vibrations depend on the length of the crystal vibrating piece. Therefore, unnecessary vibration is likely to occur at the end of the crystal vibrating piece. Therefore, unnecessary vibration can be suppressed by reducing the thickness of the crystal vibrating piece from the center to the end of the crystal vibrating piece to attenuate the vibration at the end. As a method of reducing the thickness of the quartz crystal vibrating piece from the center to the end of the quartz crystal vibrating piece, there is a method of providing an inclined surface at the end of the quartz crystal vibrating piece. Because the slope provided is the natural crystal plane of the crystal piece, the angle with respect to the main surface is large, and there is a problem that unnecessary vibration occurs at the position where the slope and the main surface intersect, not at the end of the crystal vibration piece. there were.

FIG. 7 is a front view of the quartz crystal resonator element showing the difference in dimensions that affect the occurrence of unnecessary vibration. FIG. 7A shows a quartz crystal vibrating piece 5 which is an example of a conventional quartz crystal vibrating piece, and FIG. 7B shows a quartz crystal vibrating piece 4 of the present embodiment.
As shown in FIG. 7A, in the conventional crystal resonator element 5, the angle θ2 of the inclined surface 5c with respect to the front principal surface 5a depends on the angle of the natural crystal plane, and thus is large (for example, 30 °, 40 °, 50 °). Therefore, the unnecessary vibration is not the distance (short side dimension) w4 between both ends, but the width of the line where the slope 5c intersects the front main surface 5a and the line where the slope 5c intersects the back main surface 5b. It tends to occur according to the length of the direction (Z′-axis direction) distance w2. Therefore, the reference length of the vibrating part is shortened, and the fundamental frequency of the unnecessary vibration that occurs is increased. As a result, low-order unnecessary vibration is likely to be generated along with the thickness sliding vibration of the crystal vibrating piece, and the influence of the unnecessary vibration has been increased.

  On the other hand, according to the crystal vibrating piece 4 of the present embodiment, as shown in FIG. 7B, the angle θ1 of the inclined surface 11a is formed sufficiently gently (for example, 20 ° or less). Vibration transmission is not hindered at the position where the slope 11a and the front main surface 10a intersect, and unnecessary vibration is likely to occur at the end. Therefore, the reference dimension of the vibrating part is the short side dimension w3, which is longer than that of the conventional crystal vibrating piece 5 described above. Thereby, the fundamental frequency of the unnecessary vibration which generate | occur | produces becomes low. Therefore, the unnecessary vibration that is likely to occur together with the crystal vibrating piece 4 becomes a higher-order unnecessary vibration, and the influence of the unnecessary vibration can be reduced. As a result, the vibration characteristics of the quartz crystal resonator element can be stabilized.

  Further, as described above, the vibration at the end of the crystal vibrating piece 4 is sufficiently damped, so that the intensity of unnecessary vibration generated at the end is also reduced. Therefore, it is possible to reduce the influence of unnecessary vibration on the vibration characteristics.

  In addition, according to the present embodiment, the slopes 11a provided at both ends in the short side direction (Z′-axis direction) of the quartz crystal vibrating piece 4 are inclined at an angle θ1 with respect to the front principal surface 10a. Therefore, the balance of vibration is improved, and the frequency difference between the thickness shear main vibration and the thickness sub vibration can be increased. Further, the vibration strength of the thickness sub-vibration can be reduced. Therefore, stable vibration can be obtained.

  In the present embodiment, the side surface 11b that is a natural crystal plane is a plane that intersects the Z ′ axis. Therefore, the suppression effect is high with respect to bending vibration, in particular, unnecessary vibration.

Further, according to the method for manufacturing the crystal vibrating piece 4 of the present embodiment, before the wafer S is processed by wet etching, the surface to be processed is dry-etched.
As described above, a normal crystal has a property that a natural crystal plane having a specific angle appears on an unmasked exposed surface due to etching anisotropy unique to the crystal. The specific angle in the natural crystal plane is an angle determined depending on which position or plane of the crystal crystal is etched, and is, for example, a value of 30 °, 40 °, 50 °, 90 °, or the like.

  On the other hand, according to the present embodiment, when dry etching is performed on the main surface of the wafer S and then wet etching is performed, the masked surface side (inside the mask) Etching advances to the above, and a slope that does not depend on a specific angle of the natural crystal plane as described above can be formed.

  When the surface of the wafer S is dry-etched, the surface is flattened and extremely minute protrusions are formed on the surface of the wafer S. Although the detailed principle is unknown, the minute protrusions formed by the dry etching cause a minute gap between the etching protection film formed thereafter and the surface of the wafer S, and the etching solution enters there. Therefore, it is considered that etching has progressed inside the mask.

Thereby, the slope which does not depend on the angle of the natural crystal plane to be formed becomes a gentle slope with respect to the main surface in the natural crystal plane.
Therefore, according to the present embodiment, it is possible to manufacture a quartz crystal resonator element having a slope whose inclination angle with respect to the main surface is gentler than that of the natural crystal plane, and the vibration energy confinement accuracy can be improved.

  Moreover, the surface roughness of the slope 11a formed by this method becomes low. Therefore, the impedance of the crystal vibrating piece 4 can be lowered. As the value of the surface roughness, for example, the center line average roughness is 0.2 nm or more and 10 nm or less.

[Modification of First Embodiment]
Next, a modification of the first embodiment in which the short side direction of the quartz crystal vibrating piece is the X axis and the long side direction is the Z ′ axis will be described.
FIGS. 8A and 8B are diagrams showing a crystal vibrating piece 4A according to a modification of the first embodiment, in which FIG. 8A is a front view, FIG. 8B is a plan view, and FIG. 8C is a side view. It is.
As shown in FIG. 8, the crystal vibrating piece 4A includes a crystal vibrating plate 10A and a pair of electrode films 20 respectively formed on the front and back main surfaces of the crystal vibrating plate 10A.
The crystal diaphragm 10A includes a convex portion 60 on the side surface on the long side. The convex portion 60 is formed by a natural crystal plane that appears on a plane intersecting the X axis.

  According to this embodiment, the natural crystal plane (convex portion 60) is a plane that intersects the X axis. Therefore, the suppression effect is high especially on the contour vibration among unnecessary vibrations.

[Second Embodiment]
Next, a second embodiment in which a slope is provided on the short side of the quartz crystal vibrating piece will be described.
FIGS. 9A and 9B are diagrams showing the crystal vibrating piece 70 of the second embodiment, in which FIG. 9A is a front view, FIG. 9B is a plan view, and FIG. 9C is a side view.
As shown in FIG. 9, the crystal vibrating piece 70 includes a crystal vibrating plate 71 and a pair of electrode films 20 formed on the front and back main surfaces of the crystal vibrating plate 71.

The side surface 72b along the short side direction (X-axis direction) of the front and back main surfaces 71a and 71b in the crystal diaphragm 71 is a natural crystal surface, and is substantially perpendicular to the front and back main surfaces 71a and 71b over its entire length. It is considered to be a good surface.
At both ends of the major surface 71a in the long side direction (Z′-axis direction), slopes 72a that are inclined with respect to the major surface 71a are formed over the entire length of the shorter side of the major surface 71a.

  According to the present embodiment, since the inclined surface 72a is provided along the short side of the front main surface 71a, from the central portion of the quartz crystal vibrating piece 70 toward both sides in the long side direction (± Z ′ direction side). Therefore, the vibration is attenuated. Therefore, the vibration transmitted from the central portion is sufficiently attenuated at the end portion on the one side in the long side where the mount electrode 23 is provided (the −Z ′ direction side). Therefore, when the crystal vibrating piece 70 is mounted on the crystal resonator, vibration leakage due to the mount electrode 23 coming into contact with the inner electrode formed on the base substrate via the mounting portion can be reduced.

  In the present embodiment, the long side direction is the Z ′ axis, but it may be the X axis. In that case, the side surface 72b becomes a slope that forms the convex portion 60 shown in the modified example of the first embodiment described above.

[Third Embodiment]
Next, a third embodiment in which slopes are provided on the short side and the long side of the crystal vibrating piece will be described.
FIGS. 10A and 10B are views showing the quartz crystal resonator element 100 according to the third embodiment, in which FIG. 10A is a front view, FIG. 10B is a plan view, and FIG. 10C is a side view.
As shown in FIG. 10, the quartz crystal resonator element 100 according to the present embodiment includes a quartz crystal plate 101 and a pair of electrode films 20 formed on the front and back main surfaces of the quartz plate 101.

  The side surface 102b along the short side direction (Z′-axis direction) and the side surface 103b along the long-side direction (X-axis direction) of the front and back main surfaces 101a and 101b of the crystal diaphragm 101 are front and back main surfaces over the entire length. The surfaces are substantially perpendicular to the surfaces 101a and 101b.

At both ends in the short side direction (Z′-axis direction) of the main surface 101a, slopes 103a that are inclined with respect to the main surface 101a are formed over the entire length of the long side of the main surface 101a.
On both ends of the major surface 101a in the long side direction (X-axis direction), slopes 102a that are inclined with respect to the major surface 101a are formed over the entire length of the shorter side of the major surface 101a.
The inclination angles of the inclined surfaces 102a and 103a with respect to the front and back main surfaces 101a and 101b are formed more gently than the natural crystal plane.

  According to the present embodiment, since both the long side direction (X-axis direction) and the short side direction (Z′-axis direction) have slopes whose slopes with respect to the main surface are gentler than the natural crystal plane. The vibrations at the ends in both the long side direction and the short side direction can be sufficiently damped. Therefore, it is possible to further improve the effect of confining vibration energy in the center portion of the quartz crystal resonator element.

[Fourth Embodiment]
Next, a fourth embodiment will be described in which slopes are provided on each of the four sides of the front and back main surfaces.
FIGS. 11A and 11B are views showing the quartz crystal vibrating piece 110 according to the fourth embodiment, in which FIG. 11A is a front view, FIG. 11B is a plan view, and FIG. 11C is a side view.
As shown in FIG. 11, the quartz crystal vibrating piece 110 includes a quartz crystal vibrating plate 111 and a pair of electrode films 20 formed on the front and back main surfaces of the quartz crystal vibrating plate 111.
In the four sides of the back main surface 101b of the quartz crystal vibrating piece 110, slopes 102a and 103a are formed as in the third embodiment described above.

  According to the present embodiment, it is possible to further improve the effect of confining vibration energy in the central portion of the crystal vibrating piece.

[Fifth Embodiment]
Next, a fifth embodiment, which is a mesa type crystal vibrating piece, will be described.
FIGS. 12A and 12B are views showing the quartz crystal vibrating piece 120 of the fifth embodiment, in which FIG. 12A is a front view, FIG. 12B is a plan view, and FIG. 12C is a side view.
As shown in FIG. 12, the quartz crystal vibrating piece 120 includes a quartz crystal plate 121 and a pair of electrode films 20 formed on the front and back main surfaces of the quartz plate 121.

The quartz crystal diaphragm 121 includes a rectangular parallelepiped 200a and quadrangular pyramid-shaped convex portions 200b provided at the central portions of the base surfaces 124a and 124b of the rectangular parallelepiped 200a.
The side surfaces 122b and 123b of the rectangular parallelepiped 200a are provided substantially perpendicular to the base surfaces 124a and 124b.
The convex part 200b is provided so that the surface with the larger area is in contact with the base surfaces 124a and 124b of the rectangular parallelepiped 200a, and the opposite surface is the front and back main surfaces 121a and 121a of the crystal vibrating piece 120, respectively. 121b. Excitation electrodes 21 are provided on the front and back main surfaces 121a and 121b, and the front and back main surfaces 121a and 121b are parallel to the base surfaces 124a and 124b of the rectangular parallelepiped 200a.

  In the convex portion 200b, the slope 122a along the short side direction (Z′-axis direction) and the slope 123a along the long side direction (X-axis direction) have angles with respect to the front and back main surfaces 121a and 121b, respectively, from the natural crystal plane. Is also slowly formed.

[Sixth Embodiment]
Next, a sixth embodiment, which is an inverted mesa type crystal vibrating piece, will be described.
FIGS. 13A and 13B are views showing a crystal vibrating piece 130 according to the sixth embodiment, in which FIG. 13A is a front view, FIG. 13B is a plan view, and FIG. 13C is a side view.
As shown in FIG. 13, the crystal vibrating piece 130 includes a crystal vibrating plate 131 and a pair of electrode films 20 formed on the front and back main surfaces of the crystal vibrating plate 131.

The quartz diaphragm 131 is a rectangular parallelepiped, and a recess 210 is formed at the center of each of the base surfaces 134a and 134b. The side surfaces 132b and 133b of the crystal diaphragm 131 are provided substantially perpendicular to the base surfaces 134a and 134b.
The recess 210 is formed so that the side surface is a slope. The bottom surfaces of the recesses 210 are front and back main surfaces 131a and 131b on which the excitation electrode 21 is formed, and are formed in parallel with the base surfaces 134a and 134b of the quartz crystal vibrating plate 131. The slope 133a which is a side surface along the long side direction (X-axis direction) of the recess 210 and the slope 132a which is a side surface along the short side direction (Z′-axis direction) have angles with respect to the front and back main surfaces 131a and 131b, respectively. It is formed more slowly than the natural crystal plane.

  DESCRIPTION OF SYMBOLS 1 ... Crystal oscillator, 4, 4A, 70, 100, 110, 120, 130 ... Crystal vibrating piece, 10a, 71a, 101a, 121a, 131a ... Front main surface (main surface), 10b, 71b, 101b, 121b, 131b ... back main surface (main surface), 11a, 72a, 102a, 103a, 122a, 123a, 132a, 133a ... slope, 11b, 72b, 102b, 103b, 122b, 123b, 132b, 133b ... side, 40a ... mask, S ... wafer

Claims (11)

In the crystal vibrating piece formed by AT cut,
A pair of main surfaces provided opposite to each other;
A side surface that intersects the main surface and is formed as a natural crystal surface;
Connecting the main surface and the side surface, and an inclined surface formed at an inclination angle smaller than the natural crystal surface with respect to the main surface;
A quartz crystal vibrating piece.   2. The crystal vibrating piece according to claim 1, wherein the inclined surface is formed at a position corresponding to two opposing sides of at least one of the main surfaces.   The quartz crystal resonator element according to claim 1, wherein the side surface is a surface that intersects the X axis.   The quartz crystal resonator element according to claim 1, wherein the side surface is a surface intersecting with the Z ′ axis.   5. The crystal vibrating piece according to claim 1, wherein the main surface is a quadrangle, and the inclined surface is formed at a position corresponding to four sides of at least one of the main surfaces. 6.   6. The crystal vibrating piece according to claim 1, wherein the inclined surface is formed at a position corresponding to a side of the main surface on one side and the main surface on the other side.   The quartz crystal resonator element according to claim 1, wherein the inclination angle is 20 ° or less.   The quartz crystal resonator element according to any one of claims 1 to 7, wherein a center line average roughness of the slope is 0.2 nm or more and 10 nm or less.   A crystal resonator comprising the crystal resonator element according to claim 1. A method of manufacturing a quartz crystal vibrating piece formed by AT cutting,
A step of dry-etching at least one of both surfaces of the wafer;
Forming a mask of an external pattern of a quartz crystal vibrating piece on the dry-etched surface;
Forming a slope on the dry-etched surface of the wafer by wet etching;
Removing the mask;
Dividing the wafer into pieces along the outline pattern;
A method for manufacturing a quartz crystal vibrating piece having   11. The method for manufacturing a crystal vibrating piece according to claim 10, wherein in the step of separating into pieces, a natural crystal plane intersecting with the surface of the wafer is formed by wet etching.

Images