JP5272651B2 - Manufacturing method of vibrating piece - Google Patents

Description

  The present invention relates to a quartz crystal vibrating piece and a manufacturing method thereof, and more particularly to a shape of a quartz crystal vibrating piece for preventing propagation of a thickness shear vibration as a main vibration to an outer peripheral portion, and a manufacturing method thereof.

  Conventionally, in various information / communication equipment, OA equipment, and electronic equipment such as consumer equipment, a piezoelectric device including a piezoelectric vibrator is widely used as a clock source of an electronic circuit. As a piezoelectric material used for the piezoelectric vibrator of such a piezoelectric device, for example, a single crystal crystal is adopted because stable frequency characteristics can be obtained. This quartz crystal vibrating piece consists of a quartz crystal wafer as a single crystal substrate cut out at a predetermined cutting angle from a quartz lambard in which a portion of an artificial quartz crystal is formed into a block shape with a clear crystal axis (optical axis). Formed using. Here, the predetermined cutting angle refers to a cutting angle that is inclined by a target angle with respect to the crystal axis of the crystal, for example, using a crystal wafer that is cut at a cutting angle of 35 ° 15 ′ from the crystal axis. The formed AT-cut quartz-crystal vibrating piece has long been used as a piezoelectric vibrating piece having excellent temperature characteristics that can obtain a stable frequency in a wide temperature range.

  The thickness shear vibration, which is the main vibration of the AT-cut quartz crystal vibrating piece, is arranged such that the excitation electrode vibrates at the center of the vibrating piece, but the thickness shear vibration that vibrates at the center is Propagated to the outer periphery of A part of the outer periphery of the resonator element is a holding part that is secured to a storage container such as a package, so that the vibration propagated from the center part of the resonator element is suppressed, affecting the thickness shear vibration that is the main vibration. Alternatively, vibration energy leaks from the holding part, and crystal impedance (hereinafter referred to as “CI value”) decreases, or other vibration modes are induced to decrease the stability of the oscillation frequency.

In order to prevent the vibration propagated to the outer periphery of the vibrating piece as described above and prevent the leakage and stabilize the oscillation frequency, the vibrating piece is made into a convex shape by performing a convex process or the like. A method of concentrating vibration energy on the central portion of the main surface of the vibration piece by suppressing the propagation of vibration to the outer periphery of the vibration piece by using a thin outer peripheral portion has been implemented.
Conventionally, in order to form a vibrating piece having a convex shape in cross section, for example, a convex process using a barrel polishing machine has been performed. A barrel polishing machine puts hundreds to thousands of crystal element pieces cut out from a quartz base plate (crystal wafer) into a rectangular shape with a polishing agent into a pot together with an abrasive and puts the pot at a predetermined speed. By rotating for a time, a convex convex cross section is formed.
However, the convex machining of the vibrating piece by this barrel polishing machine has a problem in that it takes a long time, so that the manufacturing efficiency and productivity are low, and the control of the convex shape is difficult and the desired machining accuracy is difficult to obtain.
As an alternative to the convex processing by such a barrel polishing machine, for example, in Patent Document 1, the cross-sectional convex shape of the quartz crystal vibrating piece is approximately replaced with a stepped shape to obtain the same vibration confinement effect as the cross-sectional convex shape, In addition, a method of manufacturing the resonator element having the staircase shape by photolithography in which the etching resist dimension is changed stepwise is disclosed.

JP 58-47316 A

  However, in the method of etching by changing the dimensions of the etching resist stepwise, as in the method of manufacturing the step-shaped vibrating piece (thickness-slip quartz crystal resonator) approximate to the cross-sectional convex shape described in Patent Document 1, photolithography is used for the etching method. Since it is necessary to repeat the process many times, the process is complicated and takes a lot of man-hours, which may reduce the productivity and increase the manufacturing cost.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.
The manufacturing method of the resonator element according to the first aspect of the invention includes a vibrating portion that vibrates by thickness-shear vibration, and is provided integrally with the vibrating portion along an outer edge of the vibrating portion, and is thicker than the vibrating portion. A thin-walled portion, and a method of manufacturing a vibrating piece in which a groove is provided in the thin-walled portion along at least a part of the periphery of the vibrating portion, the step of preparing a wafer, A step of preparing a wafer in which a main surface of a region corresponding to the resonator element is covered with a resist so as to exclude a region corresponding to the groove; and etching a region of the wafer not covered with the resist Forming an outer shape of a region corresponding to the vibrating piece and forming the groove, preparing a wafer whose main surface of the region corresponding to the vibrating portion is covered with a resist, and the wafer Covered with that resist Free region by etching, characterized in that it comprises a step of forming the vibrating portion.
The method for manufacturing a resonator element according to the second aspect of the invention is characterized in that the step of forming the vibrating portion is performed after the step of forming the outer shape and forming the groove .

  Application Example 1 In the quartz crystal resonator element according to this application example, excitation electrodes are formed at opposite positions of both main surfaces of the quartz base material, and the excitation electrode is disposed at one end of the outer peripheral portion of the quartz base material. And a support portion in which an external connection electrode drawn from is formed, and a V-groove is provided on at least one of the one end side and the other end side outside the excitation electrode of the crystal base material. And

  According to this configuration, the propagation of the thickness shear vibration from the center portion to the outer peripheral portion of the quartz crystal vibrating piece can be suppressed by the V groove provided outside the excitation electrode of the quartz crystal vibrating piece. In addition, since the V-groove that can be formed by utilizing the anisotropy of the quartz crystal is hardly etched after being etched to a certain depth, the V-groove is formed by, for example, external etching of the crystal vibrating piece. It can be performed simultaneously with other etching processes. Accordingly, a decrease in the CI value and coupling with other vibration modes are suppressed, and a crystal resonator element having a stable oscillation frequency can be efficiently manufactured by a relatively simple process.

  Application Example 2 In the quartz crystal resonator element according to the application example described above, a plurality of the V grooves are arranged in parallel.

  According to this configuration, the thickness shear vibration from the central part toward the outer peripheral part of the crystal vibrating piece is attenuated stepwise by the plurality of V grooves, thereby suppressing the propagation of vibration to the outer peripheral part more effectively. can do.

  Application Example 3 In the quartz crystal resonator element according to the application example, the V-groove is formed on the one end side of the quartz base material and in a region between the excitation electrode and the support portion. It is characterized by.

  According to this configuration, in the state where the support portion of the crystal vibrating piece is bonded to the external substrate, leakage of the thickness shear vibration from the support portion toward the outside can be suppressed, so that a decrease in the CI value can be suppressed. .

  Application Example 4 In the quartz crystal resonator element according to the application example, the V groove is formed in a region different from a region where the excitation electrode, the external connection electrode, and the inter-electrode wiring that connects them are provided. It is characterized by that.

  According to this configuration, since the electrodes and wiring are provided in a flat region different from the region where the V-groove of the crystal vibrating piece is provided, it is possible to stably form the electrodes and wiring, and problems such as disconnection Can be prevented.

  Application Example 5 In the quartz crystal resonator element according to this application example, excitation electrodes are formed at opposite positions of both main surfaces of the crystal base material, and at least one main surface of both main surfaces of the crystal base material A projecting portion having a predetermined shape, and having a support portion on which an external connection electrode led out from the excitation electrode is formed on one end side of the outer peripheral portion of the crystal base material, and the excitation electrode of the crystal base material A V-groove is provided in at least one of the one end side and the other end side on the outside.

  According to the quartz resonator element having the above-described configuration, a so-called mesa capable of concentrating the thickness-shear vibration more under the excitation electrode by the convex portions provided on the opposite surfaces of the two main surfaces and having the excitation electrodes formed on the surfaces. It has a structure. In addition, the V-groove provided outside the excitation electrode can suppress the propagation of the thickness-shear vibration to the outer peripheral portion, so that the reduction of the CI value and the coupling with other vibration modes are suppressed, and it is more stable. A crystal resonator element having an oscillation frequency can be provided.

  Application Example 6 In the quartz crystal resonator element according to the application example described above, the plurality of V grooves are provided so as to be arranged substantially in parallel.

  According to this configuration, by making the quartz crystal resonator element having a mesa structure by the convex portion, it is possible to concentrate the thickness shear vibration more under the excitation electrode and to cause the thickness shear vibration toward the outer peripheral portion to be a plurality of V grooves. Therefore, the propagation of vibration to the outer peripheral portion can be more effectively suppressed.

  Application Example 7 In the quartz crystal resonator element according to the application example, the V groove is formed on a region between the excitation electrode and the support portion on the one end side of the quartz crystal base material. It is characterized by.

  According to this configuration, by making the crystal vibrating piece having a mesa structure by the convex portion, it is possible to concentrate the thickness shear vibration more under the excitation electrode, and the support part of the crystal vibrating piece is bonded to the external substrate. In this state, leakage of the thickness shear vibration from the support portion toward the outside can be suppressed, and a decrease in CI value can be suppressed.

  Application Example 8 In the quartz crystal resonator element according to the application example, the V-groove is formed in a region different from a region where the excitation electrode, the external connection electrode, and the inter-electrode wiring that connects them are provided. It is characterized by that.

  According to this configuration, by making the crystal vibrating piece having a mesa structure by the convex portion, it is possible to concentrate the thickness-shear vibration more under the excitation electrode, and the region where the V-groove of the crystal vibrating piece is provided. Since the electrodes and wirings are provided in different flat regions, the electrodes and wirings can be formed with a stable shape, and problems such as disconnection can be prevented.

  Application Example 9 In the quartz crystal resonator element according to the application example, the V-groove is formed outside the convex portion.

  According to this configuration, by making the crystal vibrating piece having a mesa structure by the convex portion, the thickness-shear vibration is concentrated more under the excitation electrode, and the V provided outside the convex portion where the excitation electrode is formed. Propagation of thickness-shear vibration to the outer peripheral portion can be suppressed by the groove. Therefore, propagation of thickness shear vibration to the outer peripheral portion and undesired coupling or leakage of vibration associated therewith can be more effectively suppressed, and a crystal resonator element having stable oscillation frequency characteristics can be provided. .

  [Application Example 10] In the method for manufacturing a quartz crystal resonator element according to this application example, excitation electrodes are formed at opposite positions of both main surfaces of the crystal base material, and the one end side of the outer peripheral portion of the crystal base material is used. A quartz crystal having a support portion on which an external connection electrode led out from the excitation electrode is formed, and having a V-groove provided on at least one of the one end side and the other end side outside the excitation electrode of the crystal base material. A method for manufacturing a vibrating piece, a wafer preparation step for forming a wafer made of a large crystal substrate, an outer shape and a V groove forming step for simultaneously forming the outer shape of the quartz vibrating piece and the V groove by photolithography, An electrode forming step for forming the excitation electrode and the external connection electrode, and a singulation step for taking out the quartz crystal vibrating piece formed on the wafer as an individual piece.

According to this configuration, the propagation of the thickness shear vibration from the central portion to the outer peripheral portion of the vibration piece is suppressed by the V groove provided on the outer side of the excitation electrode of the quartz crystal vibrating piece, and the thickness shear vibration is transmitted to the outer peripheral portion. By suppressing undesired coupling and leakage of propagation and vibration associated therewith, it is possible to prevent a decrease in CI value and undesired coupling of vibration, and to manufacture a crystal vibrating piece having stable oscillation frequency characteristics.
Further, since the V-groove formed by utilizing the anisotropy of quartz hardly proceeds after being etched to a certain depth, it can be performed simultaneously with the external etching of the quartz vibrating piece. Therefore, a quartz crystal resonator element having stable oscillation frequency characteristics can be efficiently manufactured by a relatively simple process.

  [Application Example 11] In the method for manufacturing a quartz crystal resonator element according to this application example, excitation electrodes are formed at opposing positions of both main surfaces of the crystal base material, and at least one of the two main surfaces of the crystal base material is used. A convex portion having a predetermined shape is provided on the main surface of the quartz substrate, and has a support portion on which an external connection electrode drawn from the excitation electrode is formed on one end side of the outer peripheral portion of the quartz substrate. A method of manufacturing a piezoelectric vibrating piece in which a V-groove is provided on at least one of the one end side and the other end side outside the excitation electrode, and a wafer preparation step of forming a wafer made of a large crystal substrate; Forming the outer shape of the quartz crystal resonator element and the V-groove simultaneously by photolithography and a V-groove forming step, forming a convex portion by forming the convex portion by photolithography, forming the excitation electrode and the external connection electrode To do And forming step, characterized in that it comprises a and a singulation step of removing the crystal vibrating piece formed on the wafer as individual pieces.

According to this configuration, the convex portion provided at the opposite position of both main surfaces has a mesa structure that can concentrate thickness shear vibration more in the central portion, and is provided outside the excitation electrode. Propagation of thickness-shear vibration to the outer peripheral portion can be suppressed by the V-groove, so that the reduction of the CI value and coupling with other vibration modes are suppressed, and a crystal vibrating piece with a more stable oscillation frequency is manufactured. can do.
Further, since the V-groove can be formed simultaneously with the formation of the outer shape of the crystal vibrating piece, the crystal vibration having the mesa structure and the V-groove can be achieved without increasing the number of steps from the manufacturing process of the crystal vibrating piece having a normal mesa structure. Pieces can be manufactured.

  Application Example 12 In the method for manufacturing a quartz crystal resonator element according to the application example, the convex portion is formed after the outer shape and the V groove forming step.

  According to this configuration, an etching resist made of a corrosion-resistant film such as chromium / gold used in the outer shape and the V-groove forming process is left, and a convex portion can be formed using the etching resist, which is efficient.

  Hereinafter, an embodiment of a quartz crystal resonator element and a manufacturing method thereof will be described with reference to the drawings.

(First embodiment)
FIG. 1A is a plan view schematically illustrating an AT-cut quartz crystal vibrating piece as a quartz crystal vibrating piece according to the present embodiment, FIG. 1B is a cross-sectional view taken along the line AA in FIG. It is BB sectional drawing of (a).
FIG. 2 is a flowchart for explaining the manufacturing process of the AT-cut quartz crystal resonator element of this embodiment.
FIG. 3 schematically illustrates an example of a piezoelectric device on which the AT-cut quartz crystal vibrating piece according to the present embodiment is mounted. (A) is a plan view seen from above, and (b) is a plan view of (a). It is CC sectional view taken on the line. In FIG. 3A, the lid body 30 that covers the upper portion of the piezoelectric device 50 is not shown for convenience in describing the internal structure of the piezoelectric device 50. The hatched hatching in FIGS. 1 (a) and 3 (a) is intended to facilitate identification of electrodes such as excitation electrodes and wiring, and does not indicate a cross section.

[AT-cut crystal vibrating piece]
In FIG. 1, an AT-cut quartz crystal resonator element 10 is located at a position where both main surfaces of a quartz substrate 1 formed by using an AT-cut quartz wafer cut at a cutting angle inclined by 35 ° 15 ′ from the crystal axis are opposed to each other. Further, it has a so-called mesa structure in which convex portions 5A and 5B having a rectangular shape in plan view are formed.
Further, V grooves 7A and 8A arranged in parallel with the two sides of the convex portion 5A are provided on the outer sides of the two opposite sides of the convex portion 5A of the quartz substrate 1. Similarly, V grooves 7B and 8B arranged in parallel to the two sides of the convex portion 5B are provided outside the two opposite sides of the convex portion 5B.
The outer shape of the quartz substrate 1 having the mesa structure and the V grooves 7A, 8A, 7B, and 8B are obtained by wet etching the quartz substrate 1 (quartz wafer) with a hydrofluoric acid solution or the like by photolithography as described later. It can be formed precisely by dry etching.

As shown in FIG. 1A, an excitation electrode 15 </ b> A that is a driving electrode is provided on one convex portion 5 </ b> A of the crystal substrate 1. Further, on the surface of the quartz substrate 1 on the convex portion 5A side, an external connection electrode 17A connected to the excitation electrode 15A and the interelectrode wiring 16A is provided in the vicinity of one end side of the outer peripheral portion. Similarly, an excitation electrode 15B is provided on the other convex portion 5B of the quartz substrate 1 (see FIG. 1B), and one end side of the outer peripheral portion on the surface of the quartz substrate 1 on the convex portion 5B side. The external connection electrode 17B provided in the vicinity is connected by an interelectrode wiring 16B.
Such electrode patterns such as electrodes and wiring are formed after etching the quartz substrate 1 (quartz wafer) to form the outer shape of the AT cut quartz crystal vibrating piece 10 having a mesa structure and the V grooves 7A, 8A, 7B, 8B. It can be formed by depositing, for example, nickel (Ni) or chromium (Cr) as a base layer by vapor deposition or sputtering, forming a metal film of, for example, gold (Au) thereon, and then patterning using photolithography.

[Piezoelectric device]
Next, a piezoelectric device using the AT cut quartz crystal vibrating piece 10 will be described.
In FIG. 3, the piezoelectric device 50 includes the AT-cut quartz crystal vibrating piece 10 bonded to a package 20 in which a plurality of ceramic insulating substrates are stacked, and a metal lid 30 is bonded to the package 20. Thus, the AT-cut quartz crystal resonator element 10 is hermetically sealed in the package 20.

The package 20 is formed by laminating a substantially rectangular flat plate-like first layer substrate 21 made of a ceramic insulating material, a substantially rectangular frame-shaped second layer substrate 22, a third layer substrate 23, and a seal ring 29 in this order. Has been. The opening portions of the substantially rectangular frame-like second layer substrate 22 and third layer substrate 23 are formed larger in the upper layer, so that a recess having a plurality of steps is formed inside the package 20.
A plurality of mounting terminals 25 </ b> A and 25 </ b> B for connection to an external circuit board are formed on the lower surface side of the first layer substrate 21 that is the outer bottom surface of the package 20. Mount terminals 26 </ b> A and 26 </ b> B to which the AT-cut quartz crystal vibrating piece 10 is bonded are formed on the step formed in the package 20 by the second layer substrate 22. The mounting terminals 25A and 25B and the mount terminals 26A and 26B are connected by a wiring pattern (not shown) or an in-layer wiring pattern such as a through hole so that one circuit of the piezoelectric device 50 is formed.
These electrode terminals and wiring patterns are generally formed by screen-printing and firing a metal wiring material such as tungsten (W) or molybdenum (Mo) on a ceramic insulating material, and nickel (Ni) or gold (Au) thereon. It is formed by plating.

  In the package 20, the AT-cut quartz crystal vibrating piece 10 is joined in a cantilevered state. Specifically, the external connection electrodes 17A and 17B of the AT-cut quartz crystal vibrating piece 10 are aligned with the corresponding mount terminals 26A and 26B of the package 20 and joined by the conductive adhesive 45. As a result, the support part 11 side where the external connection electrodes 17A and 17B of the AT-cut quartz crystal vibrating piece 10 are formed is bonded onto the step of the second layer substrate 22 of the package 20, and the other end protrudes on the first layer substrate 21. It is cantilevered in the installed manner.

  On the upper side of the package 20, a metal lid 30 is seam-welded through a seal ring 29 formed by punching out an iron-nickel (Fe—Ni) alloy or the like into a frame shape. The joined AT-cut quartz crystal vibrating piece 10 is hermetically sealed.

According to the AT-cut quartz crystal resonator element 10 of the above embodiment, the mesa structure is formed by the convex portions 5A and 5B that are provided on the opposing surfaces of the two main surfaces of the quartz substrate 1 and on which the excitation electrodes 15A and 15B are respectively formed. Therefore, the thickness shear vibration when the AT-cut quartz crystal vibrating piece 10 is excited can be concentrated more under the excitation electrodes 15A and 15B. Thereby, propagation of the thickness shear vibration of the AT-cut quartz crystal vibrating piece 10 to the outer peripheral portion is suppressed.
Further, the AT-cut quartz crystal vibrating piece 10 of the above embodiment is provided with V grooves 7A and 8A on the outer sides of the two opposite sides of the convex portion 5A, and V grooves 7B and 8B on the outer sides of the two opposite sides of the convex portion 5B. Since 8B is provided, the propagation of the thickness shear vibration suppressed by the mesa structure to the outer peripheral portion can be further suppressed.
Further, since the AT-cut quartz crystal vibrating piece 10 has a mesa structure, the thickness of the support portion 11 joined to the package 20 is smaller than the mesa portion that concentrates the thickness-shear vibration by the convex portions 5A and 5B. Therefore, the leakage of vibration from the support part 11 is suppressed.
Therefore, according to the AT-cut quartz crystal resonator element 10 of the above-described embodiment, the thickness shear vibration is concentrated in the central portion, and further, the propagation to the outer peripheral portion is suppressed, thereby reducing the CI value and coupling with other vibration modes. Can be provided, and the AT-cut quartz crystal vibrating piece 10 having stable frequency characteristics can be provided.

[Manufacturing method of AT-cut crystal vibrating piece]
Next, a manufacturing method of the AT cut quartz crystal vibrating piece 10 of the above embodiment will be described.
As shown in FIG. 2, in manufacturing the AT-cut quartz crystal vibrating piece 10, first, a wafer made of a large-sized quartz substrate that has been AT-cut is prepared (step S1). Specifically, a cutting angle inclined by 35 ° 15 ′ from the crystal axis of the quartz crystal by using a wire saw or band saw from a quartz lambard obtained by forming a part of an artificial quartz stone into a block shape with a clear crystal axis. An AT-cut quartz substrate wafer cut out with the aim of is obtained. Then, the cut wafer is polished so as to have a desired thickness and surface state while accurately correcting the cutting angle.

  Next, as shown in step S2, the outer shape and the V groove are formed by simultaneously forming the outer shape and the V groove of one or a plurality of AT-cut crystal vibrating pieces 10 on the quartz substrate wafer by wet etching using photolithography. .

  More specifically, first, a corrosion resistant film made of, for example, chromium (Cr) and gold (Au) serving as an etching mask is formed on both the main surfaces of the quartz substrate wafer by sputtering, and then a photoresist is applied. A mask for patterning the outer shape of the AT-cut quartz crystal vibrating piece 10 is disposed on the photoresist, and a mask for patterning a V-groove corresponding to the shape of the upper openings of the plurality of V-grooves 7A, 8A, 7B, 8B is also disposed. . Here, it is needless to say that an outer shape / V-groove patterning mask in which the outer shape pattern and the V-groove pattern of the AT-cut crystal vibrating piece 10 are drawn on one mask may be used.

  Then, after the exposure, the exposed portion of the photoresist is developed and removed, and then immersed in an etching solution, and the corrosion-resistant film of the portion where the exposed photoresist is removed is etched to form an AT made of the corrosion-resistant film on the wafer. An outer shape of the cut quartz crystal vibrating piece 10 and an etching mask for forming a plurality of V grooves 7A, 8A, 7B, 8B are formed.

Thereafter, the wafer on which the outer shape of the AT-cut quartz crystal vibrating piece 10 and the etching mask for forming the plurality of V grooves 7A, 8A, 7B, and 8B are formed is immersed in an etching solution made of, for example, a hydrogen fluoride solution and an ammonium fluoride solution. Etching is performed until a portion corresponding to the outer shape of the AT-cut quartz crystal vibrating piece 10 of the wafer penetrates.
Note that the outer shape of the AT-cut quartz crystal vibrating piece 10 is connected to the wafer by a perforated break-off portion so as not to be completely separated from the wafer. Thereby, after the subsequent steps are efficiently flowed in the wafer state, the individual AT-cut quartz crystal vibrating piece 10 can be obtained by finally folding the folding portion.

  Here, the width of the V-groove patterning mask corresponding to the shape of the upper opening of the V-groove (the width of the upper opening) is until the portion corresponding to the outer shape of the AT-cut crystal vibrating piece 10 of the wafer penetrates. Even if the etching is performed, the portion of the wafer where the V-groove is to be formed is about 50% of the width dimension in the electric axis (X-axis) direction of the crystal due to the inclined surface formed by the crystal anisotropy. The progress of etching stops at the depth. That is, the width of the V-groove patterning mask corresponding to the shape of the upper opening of the V-groove (the width of the upper opening) is etched until the portion corresponding to the outer shape of the AT-cut crystal vibrating piece 10 of the wafer penetrates. However, it is designed so that the portion where the V-grooves 7A, 8A, 7B and 8B are to be formed does not penetrate.

Next, as shown in step S3, the convex portions 5A and 5B are formed using photolithography. That is, a photoresist is applied on the outer shape of the AT-cut quartz-crystal vibrating piece 10 and an etching mask made of a corrosion-resistant film used in the steps of forming the plurality of V-grooves 7A, 8A, 7B, and 8B. Etching is performed after exposing and developing the shapes of 5A and 5B, thereby forming etching masks for the convex portions 5A and 5B by the corrosion-resistant film. Then, the protrusions 5A and 5B are formed by immersing the wafer in an etching solution made of, for example, a hydrogen fluoride solution and an ammonium fluoride solution for a predetermined time.
As in this embodiment, after the outer shape of the AT-cut quartz crystal vibrating piece 10 and the steps of forming the plurality of V grooves 7A, 8A, 7B, and 8B, the process for forming the convex portions 5A and 5B is performed. Since the etching resist for the convex portions 5A and 5B can be formed by utilizing the outer shape of the cut crystal vibrating piece 10 and the corrosion-resistant film used in the steps of forming the plurality of V grooves 7A, 8A, 7B, and 8B, it is efficient. .

  Next, as shown in step S4, after removing the etching mask for forming the convex portions 5A and 5B made of the corrosion-resistant film, the excitation electrodes 15A and 15B, the external connection electrodes 17A and 17B, and the like are formed by sputtering or vapor deposition. Electrodes such as interelectrode wirings 16A and 16B are formed to connect them correspondingly.

  Next, as shown in step S5, individual AT-cut quartz crystal vibrating pieces 10 are broken off from the quartz substrate wafer by the above-described folding unit, and individual AT-cut quartz crystal vibrating pieces 10 are obtained. Then, the manufacturing process of the series of AT-cut quartz crystal vibrating piece 10 is completed.

According to the manufacturing method of the AT-cut quartz crystal resonator element 10 of the above embodiment, the V grooves 7A, 8A, 7B, and 8B that suppress the propagation of the thickness-shear vibration to the outer peripheral portion are used by utilizing the anisotropy of the crystal. Since the AT cut quartz crystal vibrating piece 10 can be formed simultaneously with the outer shape formation, the AT cut quartz crystal vibrating piece 10 having the V grooves 7A, 8A, 7B, 8B can be efficiently manufactured by a relatively simple process. Can do.
Moreover, according to the said manufacturing method, it is set as the process order which forms convex part 5A, 5B after the external shape of AT cut quartz-crystal vibrating piece 10, and several V groove 7A, 8A, 7B, 8B formation process. The etching resist for the convex portions 5A and 5B can be formed by using the outer shape of the AT-cut crystal vibrating piece 10 and the corrosion-resistant film used in the steps of forming the plurality of V grooves 7A, 8A, 7B, and 8B. Is good.

  The AT-cut quartz crystal resonator element and the manufacturing method thereof described in the above embodiment can be implemented as the following modifications.

(Modification 1)
In the AT-cut quartz crystal vibrating piece 10 of the above embodiment, one V groove 7A, 8A, 7B, 8B is provided on the outer side of the two sides facing the convex portions 5A, 5B. However, the present invention is not limited to this, and a plurality of V grooves may be provided on the outer sides of the two opposite sides of the convex portion.
FIG. 4 schematically illustrates an AT-cut quartz crystal vibrating piece provided with a plurality of V-grooves on the outer sides of two opposite sides of the convex portion, where (a) is a plan view and (b) is ( It is the DD sectional view taken on the line of a). In addition, about the structure same as the said embodiment among the structures shown in FIG. 4, the same code | symbol is attached | subjected and description is abbreviate | omitted.

In FIG. 4, the AT-cut quartz crystal vibrating piece 60 is a convex portion 5A, 5B having a rectangular shape in plan view at positions where both main surfaces of the quartz substrate 1 face each other, and excitation electrodes 15A, 15B provided on the surface. Has a mesa structure formed.
On one main surface of the quartz substrate 1, two V-grooves 57A and 67A and a V-groove 58A arranged in parallel with the two sides of the convex portion 5A are provided outside the two opposite sides of the convex portion 5A. , 68A are provided.
Similarly, on the other main surface of the quartz substrate 1, two V-grooves 57B and 67B arranged in parallel with the two sides of the convex portion 5B are provided outside the two opposite sides of the convex portion 5B. And V grooves 58B and 68B are provided.

  According to the AT-cut quartz crystal vibrating piece 60 of the first modification, propagation of thickness-shear vibration from the central portion toward the outer peripheral portion of the AT-cut quartz crystal vibrating piece 60 is performed on the two opposite sides of the convex portions 5A and 5B. , The vibrations are more effectively propagated to the outer periphery by being attenuated stepwise by the two V grooves 57A, 67A, V grooves 58A, 68A, V grooves 57B, 67B, or V grooves 58B, 68B. Can be suppressed.

(Modification 2)
Further, in the AT-cut quartz crystal resonator element, the excitation electrode, the external connection electrode, and the inter-electrode wiring connecting them are formed in a region different from the region where the V-groove is provided, thereby affecting the electrodes and wiring by the V-groove. Adverse effects can be avoided.
FIG. 5 is a plan view schematically illustrating an AT-cut quartz crystal vibrating piece in which electrodes and wiring are formed in a region different from the V-groove. The AT-cut quartz crystal resonator element 80 of this modification has the same configuration as the AT-cut crystal oscillator piece 10 of the above-described embodiment except for the arrangement of the inter-electrode wiring that connects the excitation electrode and the external connection electrode. Therefore, illustration and description are omitted.

In the AT-cut quartz crystal vibrating piece 80 shown in FIG. 5, a convex portion 75A is formed on one main surface of the crystal substrate 71, and two convex portions 75A are provided on the outer sides of two opposite sides of the convex portion 75A. V-grooves 77A and 78A arranged in parallel with the sides are provided.
On one main surface of the quartz substrate 71 on which the convex portion 75A is formed, an excitation electrode 85A is provided on the convex portion 75A, and an external connection is made to the support portion 81 in the vicinity of one end side of the outer peripheral portion of the quartz substrate 71. An electrode 87A is provided. The excitation electrode 85A and the external connection electrode 87A are connected by an inter-electrode wiring 86A provided so as to be routed to a region different from the region where the V-groove 78A is formed on the crystal substrate 71.

  Similarly, although not shown, a convex portion having an excitation electrode as a counter electrode of the excitation electrode 85A on the upper surface is formed at a position opposite to the convex portion 75A on the other main surface of the quartz substrate 71, V-grooves are provided on the outer sides of the two opposing sides of the convex portion. An external connection electrode 87B is provided in the vicinity of the support portion 81, and the external connection electrode 87B and the excitation electrode are provided in an interelectrode wiring 86B provided by being routed to a region different from the region where the V-groove is formed. Connected by.

  According to the configuration of the AT-cut quartz crystal vibrating piece 80 of the second modification, the interelectrode wirings 86A and 86B that connect the excitation electrode 85A and the excitation electrode that is the counter electrode thereof to the corresponding external connection electrodes 87A and 87B, respectively. The V-groove 78A of the quartz substrate 71 and the V-groove provided on the main surface facing the V-groove 78A are arranged and routed. As described above, the inter-electrode wirings 86A and 86B arranged in a flat region different from the region where the V-groove is formed in the quartz substrate 71 can be formed with a stable shape and prevent problems such as disconnection. Can do.

(Modification 3)
The AT-cut quartz crystal vibrating pieces 10, 60, 80 of the above-described embodiment and Modifications 1 and 2 have the mesa structure in which the convex portions 5A, 5B, and 75A are formed. Even by providing the V-groove only on the outer side, it is possible to suppress the propagation of the thickness-shear vibration of the AT-cut quartz crystal vibrating piece to the outer peripheral portion and suppress the deterioration of the frequency characteristics.
FIGS. 6A and 6B schematically illustrate an AT-cut quartz crystal resonator element that suppresses propagation of vibration to the outer periphery by a V-groove without using a mesa structure. FIG. 6A is a plan view, and FIG. (a) EE sectional view taken on the line, (c) is the FF sectional view taken on the line (a). FIG. 7 is a flowchart for explaining a method of manufacturing the AT-cut quartz crystal vibrating piece according to this modification.

In FIG. 6A, the AT cut quartz crystal vibrating piece 110 has excitation electrodes 115A and 115B having substantially rectangular shapes in plan view at positions facing each other at substantially the center of both main surfaces of the quartz substrate 101 made of AT cut quartz. Each is provided.
On one main surface of the quartz substrate 101 on which the excitation electrode 115A is formed, V grooves 107A and 108A arranged in parallel with the two sides of the excitation electrode 115A are provided outside the two opposite sides of the excitation electrode 115A. Is provided.
Similarly, on the other main surface of the quartz substrate 101 where the excitation electrode 115B is formed, a V-groove disposed parallel to the two sides of the excitation electrode 115B is formed outside the two opposite sides of the excitation electrode 115B. 107B and 108B are provided (see FIG. 6B).

  On one main surface of the quartz substrate 101 where the excitation electrode 115A is formed, an external connection electrode 117A connected to the excitation electrode 115A and the interelectrode wiring 116A is provided in the vicinity of one end side of the outer peripheral portion. Similarly, on the other main surface of the quartz substrate 101 where the excitation electrode 115B is formed, an external connection electrode 117B is provided in the vicinity of one end of the outer peripheral portion, and is connected to the excitation electrode 115B and the interelectrode wiring 116B. Yes.

FIG. 7 is a flowchart for explaining a method of manufacturing the AT-cut quartz crystal vibrating piece 110 according to this modification. The manufacturing method of the AT cut quartz crystal vibrating piece 110 is the same as the manufacturing method of the AT cut quartz crystal vibrating piece 10 of the above embodiment shown in FIG.
That is, first, as shown in step S11, a wafer made of an AT-cut large crystal substrate is prepared (same as step S1 in FIG. 2).
Next, as shown in step S12, the outer shape of one or a plurality of AT cut quartz crystal vibrating pieces 110 and the V grooves 107A, 108A, 107B, and 108B are simultaneously formed on the wafer of the quartz substrate by wet etching using photolithography. An outer shape and a V-groove are formed (same as step S2 in FIG. 2).
Next, as shown in step S13, electrodes such as the excitation electrodes 115A and 115B, the external connection electrodes 117A and 117B, and the inter-electrode wirings 116A and 116B that connect them in correspondence with each other are formed by sputtering or vapor deposition (see FIG. 13). Same as step S4 in FIG. 2).
Then, as shown in step S14, individual AT-cut quartz crystal vibrating pieces 110 are obtained from the quartz substrate wafer (same as step S5 in FIG. 2), and a series of AT-cut quartz crystal vibrating pieces 110 are obtained. The manufacturing process ends.

When only the V grooves 107A, 108A, 107B, and 108B are formed outside the region where the excitation electrodes 115A and 115B are formed on the quartz substrate 101 as in the AT-cut quartz crystal vibrating piece 110 and the manufacturing method thereof according to Modification 3 above. However, the V-grooves 107A, 108A, 107B, and 108B have the effect of suppressing the propagation of the thickness shear vibration of the AT-cut quartz crystal vibrating piece 110 to the outer peripheral portion and suppressing the deterioration of the frequency characteristics.
Further, the AT-cut quartz crystal vibrating piece 110 having a stable frequency characteristic can be manufactured by a very simple process.

  The embodiment of the present invention made by the inventor has been specifically described above, but the present invention is not limited to the above-described embodiment, and various modifications are made without departing from the scope of the present invention. Is possible.

  For example, in the above-described embodiment and modification, the AT-cut quartz crystal vibrating pieces 10, 60, 80, 110 in which the V-grooves or the convex portions and the V-grooves are provided on both main surfaces of the quartz substrates 1, 71, 101 have been described. Not only this but also the structure which provides a V groove or a convex part, and a V groove only in one main surface among the both main surfaces of a quartz substrate, thickness from the center part of an oscillation piece toward an outer peripheral part It has the effect of damping the propagation of sliding vibration.

  Moreover, in the manufacturing method of the AT cut quartz crystal vibrating piece 10 of the above embodiment, the procedure for performing the convex portion forming step after the outer shape and the V groove forming step has been described. However, the AT cut quartz crystal vibrating piece 10 according to the above embodiment can be manufactured not only in this case but also in the order of performing the convex portion forming step before the outer shape and the V groove forming step.

(A) is a plan view schematically illustrating an AT-cut quartz crystal vibrating piece as a quartz crystal vibrating piece according to the present embodiment, (b) is a cross-sectional view taken along line AA in (a), and (c) is The BB sectional drawing of (a). The flowchart explaining the manufacturing process of the AT cut quartz crystal vibrating piece of this embodiment. (A) is a top view which illustrates typically an example of the piezoelectric device carrying the AT cut quartz crystal vibrating piece of this embodiment, (b) is CC sectional view taken on the line of (a). (A) is a top view which illustrates typically the modification 1 of an AT cut quartz crystal vibrating piece, (b) is the DD sectional view taken on the line of (a). The top view which illustrates typically the modification 2 of an AT cut quartz crystal vibrating piece. (A) is a top view which illustrates typically the modification 3 of an AT cut quartz crystal vibrating piece, (b) is the EE sectional view taken on the line of (a), (c) is the FF line of (a). Sectional drawing. 9 is a flowchart for explaining a method for manufacturing an AT-cut quartz crystal vibrating piece according to Modification 3.

Explanation of symbols

  1, 71, 101 ... quartz substrate, 5A, 5B, 75A ... convex portion, 7A, 7B, 8A, 8B, 57A, 57B, 58A, 58B, 67A, 67B, 68A, 68B, 77A, 78A, 107A, 107B, 108A, 108B ... V-groove, 10, 60, 80, 110 ... AT-cut quartz crystal vibrating piece, 11, 81 ... support part, 15A, 15B, 85A, 115A, 115B ... excitation electrode, 16A, 16B, 86A, 86B, 116A 116B ... interelectrode wiring, 17A, 17B, 87A, 87B, 117A, 117B ... external connection electrodes, 20 ... package, 21 ... first layer substrate, 22 ... second layer substrate, 26A, 26B ... mount terminals, 29 ... Seal ring, 30 ... lid, 45 ... conductive adhesive, 50 ... piezoelectric device.

Claims (2)

A vibration part that vibrates due to thickness-slip vibration;
A thin portion that is provided integrally with the vibrating portion along an outer edge of the vibrating portion, and is thinner than the vibrating portion;
Including
A method of manufacturing a vibrating piece in which a groove is provided in the thin portion along at least a part of the periphery of the vibrating portion ,
Preparing a wafer;
Preparing a wafer in which at least said upper major surface of a region corresponding to the resonator element so as excluding an area corresponding to the groove is covered with the resist,
A step of etching the resist not covered with the region of the wafer to form the outer shape of the region corresponding to the resonator element, and to form the groove,
A step of preparing a wafer on the main surface of a region corresponding to the vibration part is covered with the resist,
A step of forming the vibrating portion of the area which is not covered with the resist of the wafer by etching,
A method of manufacturing a resonator element comprising: In claim 1,
The step of forming the vibrating portion is performed after the steps of forming the outer shape and forming the groove .

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