JP2016144092A - Vibrator manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibrator manufacturing method capable of improving yield in a manufacturing process.SOLUTION: The vibrator manufacturing method includes: a step S5-1, in a state of mounting a vibration piece composed of an AT cut crystal substrate, for strongly exciting the vibration piece by applying driving power during use of the vibration piece, e.g. power higher than about 0.01 mW, e.g. power of 2.5 mW to 100 mW, preferably power of 10 mW to 100 mW, to an excitation electrode by using a synthesizer and an oscillation circuit or the like for strong excitation; and a step S5-2, after the step S5-1 for strongly exciting the vibration piece, for adjusting a frequency of the vibration piece. Thus, equivalent series resistance of the vibration piece, i.e. a so-called CI value, can be reduced by strongly exciting the vibration piece, and in the frequency adjustment step S5-2, an oscillation rate can be improved.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a method for manufacturing a vibrator.

  In the manufacturing process of the vibrator on which the crystal vibrating piece is mounted, generally, after the crystal vibrating piece is mounted on the package base, a frequency adjusting process for adjusting the frequency of each crystal vibrating piece is performed.

  For example, Patent Document 1 discloses a method of adjusting a vibrator frequency by etching a part of an excitation electrode by ion milling that irradiates an ion laser or the like after mounting a resonator element on a package base.

JP 2009-44237 A

  However, in the frequency adjustment process, even if the resonator element has no problem in appearance, the resonator element does not resonate and is regarded as a defective product, resulting in a decrease in yield.

  One of the objects according to some aspects of the present invention is to provide a method for manufacturing a vibrator capable of improving the yield in manufacturing.

  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 aspects or application examples.

[Application Example 1]
The method for manufacturing the vibrator according to this application example is as follows:
Applying a higher electric power to the vibrating piece than the driving power when the vibrating piece is used to strongly excite the vibrating piece;
After the step of exciting the vibrating piece, the step of adjusting the frequency of the vibrating piece;
including.

  In such a vibrator manufacturing method, since the frequency of the resonator element is adjusted after the resonator element is strongly excited, the equivalent series resistance value (CI value) of the resonator element is reduced in the frequency adjusting step as will be described later. And the oscillation rate can be improved. Therefore, according to such a method for manufacturing a vibrator, the yield at the time of manufacturing the vibrator can be improved.

[Application Example 2]
In the method for manufacturing a vibrator according to this application example,
In the step of strongly exciting the vibrating piece, electric power of 2.5 mW to 100 mW may be applied to the vibrating piece.

  In such a method of manufacturing a vibrator, as described later, the CI value of the resonator element can be reduced in the frequency adjustment step, and the oscillation rate can be improved.

[Application Example 3]
In the method for manufacturing a vibrator according to this application example,
In the step of strongly exciting the vibrating piece, electric power of 10 mW or more may be applied to the vibrating piece.

  In such a vibrator manufacturing method, as will be described later, the CI value of the resonator element can be further reduced in the frequency adjustment step, and the oscillation rate can be further improved.

[Application Example 4]
In the method for manufacturing a vibrator according to this application example,
The vibrating piece may include a quartz substrate having a vibrating portion that vibrates by thickness shear vibration.

  In such a method for manufacturing a vibrator, the yield at the time of manufacturing the vibrator can be improved.

FIG. 1A is a cross-sectional view schematically showing the vibrator according to this embodiment, and FIG. 1B is a plan view schematically showing the vibrator according to this embodiment. FIG. 6 is a perspective view schematically showing a resonator element of the vibrator according to the embodiment. FIG. 3 is a plan view schematically showing a resonator element of the vibrator according to the embodiment. FIG. 3 is a cross-sectional view schematically showing a resonator element of the vibrator according to the embodiment. FIG. 3 is a cross-sectional view schematically showing a resonator element of the vibrator according to the embodiment. The perspective view which shows an AT cut quartz substrate typically. FIG. 3 is a cross-sectional view schematically showing a resonator element of the vibrator according to the embodiment. 5 is a flowchart showing an example of a method for manufacturing a vibrator according to the embodiment. Sectional drawing which shows typically the manufacturing process of the vibrator | oscillator which concerns on this embodiment. The graph which shows the relationship between a drive level and the change rate of CI value. The graph which shows the relationship between a drive level and an oscillation rate.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. In addition, not all of the configurations described below are essential constituent requirements of the present invention.

1. First, a vibrator that is a target of the vibrator manufacturing method according to the present embodiment will be described with reference to the drawings. FIG. 1A is a cross-sectional view schematically showing a vibrator 100 according to this embodiment. FIG. 1B is a plan view schematically showing the vibrator 100 according to the present embodiment. Note that FIG. 1A is a cross-sectional view taken along line AA in FIG.

  As shown in FIGS. 1A and 1B, the vibrator 100 includes a vibrating piece 102 and a package 110. Hereinafter, the resonator element 102 and the package 110 will be described in detail.

(1) Vibrating Piece FIG. 2 is a perspective view schematically showing the vibrating piece 102. FIG. 3 is a plan view schematically showing the resonator element 102. 4 is a cross-sectional view taken along the line IV-IV in FIG. FIG. 5 is a cross-sectional view taken along the line VV in FIG. 3 schematically showing the resonator element 102.

  As shown in FIGS. 2 to 5, the vibrating piece 102 includes a quartz crystal substrate 10 and excitation electrodes 20 a and 20 b.

  The quartz substrate 10 is made of an AT cut quartz substrate. Here, FIG. 6 is a perspective view schematically showing the AT-cut quartz crystal substrate 101.

  Piezoelectric materials such as quartz are generally trigonal and have crystal axes (X, Y, Z) as shown in FIG. The X axis is an electrical axis, the Y axis is a mechanical axis, and the Z axis is an optical axis. The quartz substrate 101 is a so-called rotated Y cut out from a piezoelectric material (for example, artificial quartz crystal) along a plane obtained by rotating an XZ plane (a plane including the X axis and the Z axis) by an angle θ around the X axis. It is a flat plate of a cut quartz substrate. Note that the Y axis and the Z axis are also rotated by θ around the X axis to be the Y ′ axis and the Z ′ axis, respectively. The quartz substrate 101 is a substrate having a plane including the X axis and the Z ′ axis as a main surface and a thickness along the direction along the Y ′ axis. Here, when θ = 35 ° 15 ′, the quartz substrate 101 is an AT-cut quartz substrate. Accordingly, the AT-cut quartz crystal substrate 101 has the XZ ′ plane (plane including the X axis and Z ′ axis) orthogonal to the Y ′ axis as the main surface (the main surface of the vibrating portion), and vibrates with thickness shear vibration as the main vibration. be able to. The AT-cut quartz substrate 101 can be processed to obtain the quartz substrate 10.

  As shown in FIG. 6, the quartz substrate 10 is a crystal axis of quartz, which is an X axis of an orthogonal coordinate system comprising an X axis as an electric axis, a Y axis as a mechanical axis, and a Z axis as an optical axis. Is the rotation axis, the Z axis is tilted so that the + Z side rotates in the −Y direction, the Z ′ axis, and the Y axis is tilted so that the + Y side rotates in the + Z direction of the Z axis, and the Y ′ axis. And an AT-cut quartz substrate having a plane including the X-axis and the Z′-axis as a main surface and a thickness along the direction along the Y′-axis. 2 to 5 and FIG. 7 described below, an X axis, a Y ′ axis, and a Z ′ axis that are orthogonal to each other are illustrated.

  The quartz substrate 10 is not limited to the AT-cut quartz substrate 101, and may be a piezoelectric substrate that vibrates by other thickness-shear vibrations such as an SC-cut quartz substrate or a BT-cut quartz substrate that excites thickness-shear vibration. .

  The quartz substrate 10 has, for example, a Y′-axis direction as a thickness direction, a plan view from the Y′-axis direction (hereinafter, also simply referred to as “plan view”), an X-axis direction as a long side, and a Z′-axis It has a rectangular shape with a short side in the direction. The quartz substrate 10 has a peripheral portion 12 and a vibrating portion 14.

  The peripheral portion 12 is provided around the vibrating portion 14. The peripheral portion 12 is provided along the outer edge of the vibration portion 14. The peripheral portion 12 is thinner than the vibrating portion 14.

  The vibration part 14 is surrounded by the peripheral part 12 in plan view and is thicker than the peripheral part 12. The vibration part 14 has a side along the X axis and a side along the Z ′ axis. Specifically, the vibration unit 14 has a rectangular shape with a long side in the X-axis direction and a short side in the Z′-axis direction in plan view. The vibration unit 14 includes a first portion 15 and a second portion 16.

  The first portion 15 of the vibrating portion 14 is thicker than the second portion 16. In the illustrated example, the first portion 15 is a portion having a thickness t1. The first portion 15 has a quadrangular shape in plan view.

The second portion 16 of the vibrating portion 14 is smaller in thickness than the first portion 15. In the illustrated example, the second portion 16 is a portion having a thickness t2. The second portion 16 is provided in the + X axis direction and the −X axis direction of the first portion 15. That is, the first portion 15 is second in the X-axis direction.
It is sandwiched between the parts 16. As described above, the vibrating portion 14 includes the two types of portions 15 and 16 having different thicknesses, and the vibrating piece 102 has a two-stage mesa structure.

  The vibration unit 14 can vibrate with thickness shear vibration as the main vibration. Since the vibrating unit 14 has a two-stage mesa structure, the vibrating piece 102 can have an energy confinement effect. “Thickness shear vibration” means that the displacement direction of the quartz substrate is parallel to the main surface of the quartz substrate (in the example shown, the displacement direction of the quartz substrate is the X-axis direction), and the wave propagation direction is the thickness direction of the plate. It is the vibration of the.

  The vibration part 14 includes a first convex part 17 projecting in the + Y′-axis direction from the peripheral part 12, and a second convex part 18 projecting in the −Y′-axis direction from the peripheral part 12. Yes. For example, the convex portions 17 and 18 have the same shape, and the convex portions 17 and 18 have the same size. The convex portions 17 and 18 include the first portion 15 and the second portion 16.

  The side surface 17a in the + X-axis direction and the side surface 17b in the −X-axis direction of the first convex portion 17 and the side surface 18a in the + X-axis direction and the side surface 18b in the −X-axis direction of the second convex portion 18 are illustrated in FIG. As shown, two steps are provided depending on the difference between the thickness of the first portion 15 and the thickness of the second portion 16 and the difference between the thickness of the second portion 16 and the thickness of the peripheral portion 12.

  For example, as illustrated in FIG. 4, the side surface 17 c of the first convex portion 17 in the + Z′-axis direction is a surface perpendicular to the surface including the X-axis and the Z′-axis. The side surface 17d in the −Z′-axis direction of the first convex portion 17 is a surface that is inclined with respect to a plane including the X-axis and the Z′-axis, for example.

  For example, as illustrated in FIG. 4, the side surface 18 c of the second convex portion 18 in the + Z′-axis direction is a surface that is inclined with respect to a plane including the X-axis and the Z′-axis. A side surface 18d in the −Z′-axis direction of the second convex portion 18 is a surface perpendicular to the surface including the X-axis and the Z′-axis.

  The side surface 17d of the first convex portion 17 and the side surface 18c of the second convex portion 18 are such that, for example, when an AT-cut quartz substrate is etched using a solution containing hydrofluoric acid as an etching solution, the m-plane of the quartz crystal is exposed. Thus, the surface is inclined with respect to the plane including the X axis and the Z ′ axis. In addition, although not shown in figure, also about the side surface of -Z 'direction other than the side surfaces 17d and 18c of the quartz substrate 10, the m-plane of the quartz crystal is exposed, so that the plane including the X axis and the Z' axis is exposed. The surface may be inclined.

  Further, as shown in FIG. 7, the side surfaces 17d and 18c may be surfaces that are perpendicular to the plane including the X axis and the Z ′ axis. For example, by processing the AT cut quartz substrate by laser or etching the AT cut quartz substrate by dry etching, the side surface 17d and the side surface 18c are perpendicular to the plane including the X axis and the Z ′ axis. It can be a good surface. For convenience, FIG. 2 illustrates the case where the side surfaces 17d and 18c are surfaces perpendicular to the plane including the X axis and the Z ′ axis.

  The 1st excitation electrode 20a and the 2nd excitation electrode 20b are provided so that it may overlap with the vibration part 14 by planar view. In the illustrated example, the excitation electrodes 20 a and 20 b are further provided in the peripheral portion 12. The planar shape (shape seen from the Y′-axis direction) of the excitation electrodes 20a and 20b is, for example, a rectangle. The vibration part 14 is provided inside the outer edges of the excitation electrodes 20a and 20b in plan view. That is, the area of the excitation electrodes 20 a and 20 b is larger than the area of the vibration part 14 in plan view. The excitation electrodes 20 a and 20 b are electrodes for applying a voltage to the vibration unit 14.

The first excitation electrode 20a is connected to the first electrode pad 24a via the first extraction electrode 22a. The second excitation electrode 20b is connected to the second electrode pad 24b through the second extraction electrode 22b. The electrode pads 24 a and 24 b are provided on the + X axis direction side of the peripheral portion 12. As the excitation electrodes 20a and 20b, the extraction electrodes 22a and 22b, and the electrode pads 24a and 24b, for example, those obtained by laminating chromium and gold in this order from the quartz substrate 10 side are used.

  In the above description, the example in which the area of the excitation electrodes 20a and 20b is larger than the area of the vibration part 14 in plan view has been described. However, the area of the excitation electrodes 20a and 20b in plan view is larger than the area of the vibration part 14. May be small. In this case, the excitation electrodes 20a and 20b are provided inside the outer edge of the vibration unit 14 in plan view.

  In the above description, the two-stage mesa structure in which the vibration unit 14 has two types of portions 15 and 16 having different thicknesses has been described. However, the number of steps of the mesa structure of the resonator element 102 is not particularly limited. For example, the resonator element 102 may have a three-stage mesa structure in which the vibration part has three types of parts having different thicknesses, or a single-stage type mesa in which the vibration part does not have parts having different thicknesses. It may be a structure. The vibrating piece 102 is not limited to a mesa type, and for example, the quartz substrate 10 may have a uniform thickness, a bevel structure, or a convex structure.

  In the above description, the side surfaces 17c and 17d of the first convex portion 17 and the side surfaces 18c and 18d of the second convex portion 18 are provided with a step due to the difference between the thickness of the first portion 15 and the thickness of the second portion 16. Although an example in which the vibration piece 102 is not described has been described, the resonator element 102 may be provided with steps on the side surfaces 17c, 17d, 18c, and 18d.

  Moreover, in the above, it has the 1st convex part 17 which protrudes in the + Y'-axis direction from the peripheral part 12, and the 2nd convex part 18 which protrudes in the -Y'-axis direction rather than the peripheral part 12. However, the resonator element 102 may have only one of the convex portions.

(2) Package As shown in FIGS. 1 (A) and 1 (B), a package 110 has a box-like base 112 having a recess 111 opened on the upper surface and a base 112 so as to close the opening of the recess 111. And a plate-like lid 114 which is joined. In FIG. 1B, the lid 114 and the seal ring 113 are not shown for convenience.

  Such a package 110 has a storage space formed by closing the recess 111 with a lid 114, and the vibrating piece 102 is stored and installed in the storage space in an airtight manner. That is, the resonator element 102 is accommodated in the package 110.

  The storage space (recess 111) in which the resonator element 102 is stored may be in a reduced pressure state (vacuum state), or may be filled with an inert gas such as nitrogen, helium, or argon. Good. Thereby, the vibration characteristics of the resonator element 102 are improved.

  The material of the base 112 is, for example, various ceramics such as aluminum oxide. The material of the lid 114 is, for example, a material whose linear expansion coefficient approximates that of the base 112. Specifically, when the material of the base 112 is ceramics, the material of the lid 114 is an alloy such as Kovar.

A first connection terminal 130 and a second connection terminal 132 are provided on the bottom surface of the recess 111 of the package 110. The first connection terminal 130 is provided to face the first electrode pad 24 a of the resonator element 102. The second connection terminal 132 is provided to face the second electrode pad 24 b of the vibrating piece 102. The connection terminals 130 and 132 are electrically connected to the electrode pads 24a and 24b through the conductive fixing member 134, respectively.

  A first external terminal 140 and a second external terminal 142 are provided on the bottom surface of the package 110. The first external terminal 140 is provided at a position overlapping the first connection terminal 130 in a plan view, for example. The second external terminal 142 is provided, for example, at a position overlapping the second connection terminal 132 in plan view. The first external terminal 140 is electrically connected to the first connection terminal 130 through a via (not shown). The second external terminal 142 is electrically connected to the second connection terminal 132 through a via (not shown).

  As the connection terminals 130 and 132 and the external terminals 140 and 142, for example, Ni (nickel), Au (gold), Ag (silver), metallization layer (underlayer) such as Cr (chrome), W (tungsten), etc. A metal film in which respective films such as Cu (copper) are laminated is used. As the conductive fixing member 134, for example, solder, silver paste, conductive adhesive (adhesive in which conductive fillers such as metal particles are dispersed in a resin material), or the like is used.

2. Next, a method for adjusting the frequency of the vibrator and a method for manufacturing the vibrator according to the present embodiment will be described. FIG. 8 is a flowchart showing an example of a method for manufacturing a vibrator according to this embodiment. FIG. 9 is a cross-sectional view schematically showing a manufacturing process of the vibrator according to the present embodiment.

  The vibrator manufacturing method according to the present embodiment includes the vibrator frequency adjusting method according to the present embodiment. In the method for manufacturing the vibrator according to the present embodiment illustrated in FIG. 8, a strong excitation step S5-1 and a frequency adjustment step S5-2 are included as the frequency adjustment method for the vibrator according to the present embodiment.

  First, as shown in FIG. 9, the vibrating piece 102 is mounted on the base 112 (vibrating piece mounting step S <b> 1).

  Specifically, the resonator element 102 is fixed on the connection terminals 130 and 132 provided on the base 112 using the conductive adhesive 134 a.

  Then, the solvent of the conductive adhesive 134a is vaporized by drying the conductive adhesive 134a in a temperature atmosphere of a predetermined temperature (about 180 ° C.).

  Next, the conductive adhesive 134a is heat-treated (first annealing step S2).

  For example, the base 112 on which the resonator element 102 is mounted is introduced into an annealing furnace (not shown), and the conductive adhesive 134a is annealed at a peak heating temperature of about 200 ° C. to 300 ° C. In the first annealing step S2, for example, annealing for 4 hours including heating for 2 hours at the peak heating temperature is performed. In the first annealing step S2, the conductive fixing member 134 can be formed by curing the conductive adhesive 134a.

  Here, in the first annealing step S2, annealing may be performed in a vacuum atmosphere. By performing annealing in a vacuum atmosphere, the degree of oxidation of the excitation electrodes 20a and 20b can be reduced. Thereby, deterioration of an aging characteristic can be suppressed. The same applies to the second annealing step S4 and the third annealing step S6 described later.

  Next, the vibrating piece 102 and the conductive fixing member 134 are cooled to a predetermined temperature, and the annealing furnace is opened and ventilated (ventilation step S3).

Next, the conductive fixing member 134 and the vibrating piece 102 are heated (second annealing step S).
4).

  For example, the base 112 on which the vibrating piece 102 is mounted is introduced into an annealing furnace, and the vibrating piece 102 and the conductive fixing member 134 are heated. The second annealing step S4 is performed, for example, under the same temperature condition and the same time condition as the first annealing step S2. In the second annealing step S4, the outgas component in the conductive fixing member 134 that could not be sufficiently removed in the first annealing step S2 is removed, and the outgas component adhering to the vibrating piece 102 is removed. It is possible to reduce the stress distortion of the resonator element 102 that could not be completely eliminated in the annealing step S2.

  Next, electric power higher than the driving power when the vibrating piece 102 is used is applied to the vibrating piece 102 to vibrate the vibrating piece 102 (strong excitation step S5-1).

  Specifically, as shown in FIG. 9, when the resonator element 102 is mounted on the base 112, when the resonator element 102 is used by using a synthesizer, an oscillation circuit for strong excitation, or the like (when performing normal operation). Is applied to the excitation electrodes 20a and 20b to vibrate the resonator element 102 (overdrive). The driving power when using the resonator element 102 is, for example, about 0.01 mW. In the strong excitation step S5-1, power of 2.5 mW or more and 100 mW or less is applied to the resonator element 102. More desirably, in the strong excitation step S5-1, power of 10 mW or more and 100 mW or less is applied to the resonator element 102. The application time is, for example, 1 second or more and 30 seconds or less. By vigorously exciting the resonator element 102 in this way, the equivalent series resistance of the resonator element 102, the so-called CI (crystal impedance) value, can be reduced, and the oscillation rate can be improved in the frequency adjustment step S5-2. (Refer to “3. Experimental example” below.)

Here, the drive level is electric power for causing the resonator element 102 to oscillate, and is represented by P = I ² × Re. Note that I is a current (effective value) flowing through the resonator element, and Re is an equivalent series resistance of the resonator element. The current I flowing through the vibration piece can be obtained by acquiring the waveform of the current flowing through the vibration piece with an oscilloscope or the like on the oscillation circuit.

  Next, frequency adjustment of the resonator element 102 (vibrator 100) is performed (frequency adjustment step S5-2).

  For example, although not shown, the resonator element 102 is brought into contact with the external terminals 140 and 142 electrically connected to the excitation electrodes 20a and 20b, a monitor electrode (not shown), etc. And measure the output frequency. The drive level at this time is a drive level during normal use of the resonator element. If there is a frequency difference between the measured actual frequency and a desired frequency, the ion laser or the like is irradiated to etch a part of the excitation electrodes 20a and 20b (ion milling) to obtain a mass. The frequency is adjusted by reducing. Note that the frequency may be adjusted by forming a film on the excitation electrodes 20a and 20b and increasing the mass.

  Next, the conductive fixing member 134 and the vibrating piece 102 are heated (third annealing step S6).

  For example, the base 112 on which the vibrating piece 102 is mounted is introduced into an annealing furnace, and the vibrating piece 102 and the conductive fixing member 134 are heated. In the third annealing step S6, for example, annealing including heating for 45 minutes at a peak heating temperature of about 200 ° C. to 300 ° C. is performed.

By the third annealing step S6, the outgas component in the conductive fixing member 134 that has not been sufficiently removed by the first annealing step S2 and the second annealing step S4 and the outgas component adhering to the vibrating piece 102 are removed. In addition, in the first annealing step S2 and the second annealing step S4, the stress strain of the resonator element 102 that could not be completely eliminated can be reduced. Furthermore, the stress distortion of the resonator element 102 newly added in the frequency adjustment step S5-2 can be reduced.

  Note that the third annealing step S6 may not be performed.

  Next, as shown in FIG. 1A, a lid 114 is joined to the base 112 to seal the recess 111 of the base 112 (sealing step S7). Thereby, the resonator element 102 can be accommodated in the accommodation space (recess 111) of the package 110. The base 112 and the lid 114 are joined by providing the seal ring 113 on the base 112, placing the lid 114 on the seal ring 113, and welding the seal ring 113 to the base 112 using, for example, a resistance welding machine. Is done by. The joining of the base 112 and the lid 114 is not particularly limited, and may be performed using an adhesive or may be performed by seam welding.

  Next, the characteristics of the vibrator 100 are inspected (inspection step S8).

  For example, although not shown, the probe of the measuring device is brought into contact with the external terminals 140 and 142 electrically connected to the excitation electrodes 20a and 20b, the monitor electrode (not shown), etc. Characteristics (DLD (Drive Level Dependence) characteristics, etc.) are measured.

  Through the above steps, the vibrator 100 can be manufactured.

  The frequency adjustment method of the vibrator 100 according to the present embodiment has the following features, for example.

  In the frequency adjustment method of the vibrator 100 according to the present embodiment, a process S5-1 in which power higher than the driving power when the vibrator element 102 is used is applied to the vibrator element 102 to strongly excite the vibrator element 102, and the vibration After step S5-1 for strongly exciting the piece 102, a step S5-2 for adjusting the frequency of the vibrating piece 102 is included. Therefore, the CI value of the resonator element 102 can be reduced, and the oscillation rate can be improved in the frequency adjustment step S5-2 (see “3. Experimental example” described later). Therefore, the yield at the time of manufacturing the vibrator 100 can be improved.

  In the method for adjusting the frequency of the vibrator 100 according to the present embodiment, power of 2.5 mW or more and 100 mW or less is applied to the resonator element 102 in step S5-1 for strongly exciting the resonator element 102. As a result, the CI value of the resonator element 102 can be reduced and the oscillation rate can be improved (see “3. Experimental example” described later).

  In the method for adjusting the frequency of the vibrator 100 according to the present embodiment, in the step S5-1 for strongly exciting the resonator element 102, electric power of 10 mW or more and 100 mW or less is applied to the resonator element 102. As a result, the CI value of the resonator element 102 can be further reduced, and the oscillation rate can be further improved (see “3. Experimental example” described later).

  Since the method for manufacturing the vibrator 100 according to the present embodiment includes the method for adjusting the frequency of the vibrator 100 according to the present embodiment, the yield at the time of manufacturing can be improved.

3. Experimental Example An experimental example is shown below to describe the present invention more specifically. The present invention is not limited by the following experimental examples.

3.1. First Experimental Example In the method for manufacturing the vibrator 100 described above, an experiment was conducted to examine the relationship between the drive level during overdrive and the change rate of the CI value before and after overdrive.

  Specifically, in the method for manufacturing the vibrator 100 described above, when the drive level during overdrive in the strong excitation step S5-1 is DL = 0.1 mW, DL = 0.5 mW, DL = 2. The CI values before and after overdrive were measured for 5 mW, DL = 10 mW, and DL = 100 mW, respectively. The vibrator was an AT cut type vibrator and the oscillation frequency was 16 MHz.

  A method for obtaining the rate of change of the CI value before and after overdrive will be described in more detail. Here, a case where DL = 0.1 mW is described as an example. First, in the method for manufacturing the vibrator 100 described above, the CI value was measured by applying a drive level DL = 0.01 mW during normal use to the resonator element before the strong excitation step S5-1. Next, in the strong excitation step S5-1, the drive level DL = 0.1 mW was applied for 1 second to 30 seconds to cause strong excitation (overdrive). Next, the drive value DL = 0.01 mW during normal use was applied again to the resonator element, and the CI value was measured. In this way, the change rate of the CI value before and after overdrive was obtained for DL = 0.1 mW.

  For other drive levels DL = 0.5 mW, 2.5 mW, 10 mW, and 100 mW, the CI value before and after overdrive was measured in the same manner, and the change rate of the CI value before and after overdrive was obtained. .

  For reference, when the drive level in the strong excitation step S5-1 is DL = 0.01 mW, that is, when the drive level during normal use is applied without strong excitation, the CI value is similarly changed. Measurements were made.

  FIG. 10 shows the relationship between the drive level DL at the time of overdrive and the rate of change of the CI value (CI2) after overdrive with respect to the CI value (CI1) before overdrive ((CI2-CI1) / CI1). It is a graph.

  As shown in FIG. 10, the CI value of the resonator element after overdrive was performed by applying a drive level DL = 2.5 mW or more was significantly reduced compared to the CI value before overdrive. Specifically, after overdriving with DL = 2.5 mW applied, the CI value decreased by 40%. In addition, after overdriving with DL = 10 mW applied, the CI value decreased by 45%. Furthermore, after performing overdrive by applying DL = 100 mW, the CI value decreased by 50%. As described above, it was found that the vibration piece is changed to a state in which it easily oscillates by applying a high drive level of drive level DL = 2.5 mW or more and performing overdrive.

3.2. Second Experimental Example Next, in the method for manufacturing the vibrator 100 described above, an experiment was conducted to examine the relationship between the drive level during overdrive and the oscillation rate after overdrive.

  Specifically, as in the first experimental example described above, when the drive level during overdrive in the strong excitation step S5-1 is DL = 0.1 mW, DL = 0.5 mW, DL = 2. The oscillation rates were measured for 5 mW, DL = 10 mW, and DL = 100 mW, respectively. The vibrator was an AT cut type vibrator and the oscillation frequency was 16 MHz.

  The oscillation rate represents the ratio of the vibrating piece that oscillates normally with respect to the total number of measurements. A normally oscillating resonator element refers to a resonator element whose CI value at DL = 0.01 mW satisfies the negative resistance of the oscillator circuit. Here, for each drive level DL, it was examined whether 1000 vibrating pieces normally oscillate.

  FIG. 11 is a graph showing the relationship between the drive level DL during overdrive and the oscillation rate after overdrive.

  As shown in FIG. 11, when the drive level DL = 0.01 mW, that is, when overdrive is not performed, the oscillation rate is about 93%, but overdrive is performed at the drive level DL = 2.5 mW or more. When performed, the oscillation rate was 100%.

  In the overdrive in which the drive level DL = 100 mW is applied to the resonator element, as described above, the CI value is reduced by 50% and the oscillation rate is 100%, so that a sufficient effect is obtained. Therefore, in order to reduce power consumption, it is desirable to perform overdrive at a drive level of 100 mW or less.

  The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

DESCRIPTION OF SYMBOLS 10 ... Quartz substrate, 12 ... Peripheral part, 14 ... Vibrating part, 15 ... 1st part, 16 ... 2nd part, 17 ... 1st convex part, 17a, 17b, 17c, 17d ... Side surface, 18 ... 2nd convex part , 18a, 18b, 18c, 18d ... side, 20a ... first excitation electrode, 20b ... second excitation electrode, 22a ... first extraction electrode, 22b ... second extraction electrode, 24a ... first electrode pad, 24b ... second Electrode pad, 100 ... Vibrating device, 100a ... Vibrator, 101 ... AT-cut quartz substrate, 102 ... Vibrating piece, 110 ... Package, 111 ... Recess, 112 ... Base, 113 ... Seal ring, 114 ... Lid, 116 ... Storage part DESCRIPTION OF SYMBOLS 119 ... Member, 130 ... 1st connection terminal, 132 ... 2nd connection terminal, 134 ... Conductive fixing member, 134a ... Conductive adhesive, 140 ... 1st external terminal, 142 ... 2nd external terminal

Claims (4)

Applying a higher electric power to the vibrating piece than the driving power when the vibrating piece is used to strongly excite the vibrating piece;
After the step of exciting the vibrating piece, the step of adjusting the frequency of the vibrating piece;
A method for manufacturing a vibrator, comprising: In claim 1,
A method of manufacturing a vibrator, wherein in the step of strongly exciting the vibrating piece, electric power of 2.5 mW or more and 100 mW or less is applied to the vibrating piece. In claim 1 or 2,
A method for manufacturing a vibrator, wherein in the step of strongly exciting the vibrating piece, electric power of 10 mW or more is applied to the vibrating piece. In any one of Claims 1 thru | or 3,
The vibrating piece includes a crystal substrate having a vibrating portion that vibrates by thickness-shear vibration.

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