JP2012205258A - Polishing method, method for manufacturing piezoelectric vibration piece, piezoelectric vibrator, oscillator, electronic equipment and electric wave clock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve thickness accuracy of a wafer at polishing.SOLUTION: There is provided a method for polishing a crystal wafer (tuning-fork substrate) 155 held by a carrier 157 between an upper surface plate 151 and a lower surface plate 152. By the disposition of an AT cut wafer 156 for thickness measurement on the carrier 157, the AT cut wafer 156 is polished together with the crystal wafer (tuning-fork substrate) 155. A resonant frequency of the AT cut wafer 156 is detected, and based on the detection result, the thickness of the crystal wafer (tuning-fork substrate) 155 is controlled.

Description

  The present invention relates to a polishing method, a method for manufacturing a piezoelectric vibrating piece, a piezoelectric vibrator having a piezoelectric vibrating piece manufactured by the method for manufacturing a piezoelectric vibrating piece, an oscillator having the piezoelectric vibrator, an electronic apparatus, and a radio timepiece.

In recent years, a package product including a base substrate and a lid substrate in which a cavity is formed by anodically bonding each other in a stacked state, and an operating piece mounted on a portion of the base substrate located in the cavity. Widely used.
As a package product of this type, for example, a piezoelectric vibrator that is mounted on a mobile phone or a portable information terminal device and uses a crystal or the like as a timing source such as a time source or a control signal, a reference signal source, or the like is known.

As such a piezoelectric vibrator, a thickness-sliding vibrator using an AT vibrating piece that performs thickness-shear vibration that is preferably used as a vibrator having a vibration frequency in the MHz band and a vibrator for a communication device is known.
This AT vibrating piece is formed into a predetermined thickness and rectangular shape after AT is cut (cut so that the main surfaces of the front and back surfaces are at an angle of about 35 degrees 15 minutes counterclockwise from the Z axis around the X axis). It is a vibration piece composed of an externally formed AT diaphragm (quartz crystal diaphragm) and an electrode film formed on the main surface of the AT diaphragm. When a voltage is applied to the electrode film, the AT diaphragm Oscillates in thickness and thickness.

  Since the resonance frequency of this thickness sliding vibrator is determined by the thickness of the AT vibration piece, the resonance frequency is detected while polishing the AT cut wafer for the AT vibration piece. A method for adjusting the thickness of the AT vibrating piece is known (for example, see Patent Document 1).

JP-A-3-251365

However, there is a problem that the method according to the prior art cannot be applied to polishing of a tuning fork wafer that vibrates in a bending mode.
In response to such a problem, when a tuning fork wafer is polished, a tuning fork is measured by using a measuring instrument that measures the amount of movement of an appropriate part of the polishing apparatus that is displaced according to the thickness of the tuning fork wafer. There is known a method for managing the thickness dimension of a manufacturing wafer.
As such a measuring device, for example, the amount of movement of this carbide measuring table is measured while bringing the measuring terminal into contact with the carbide measuring table of the grinding device that is displaced according to the thickness of the tuning fork wafer during polishing. What to do is known.
However, when the measurement terminal is brought into contact with an appropriate part of the polishing apparatus like this measuring device, the measurement position becomes the same point, so that wear occurs and the thickness accuracy of the tuning fork wafer cannot be improved. The problem arises.

  The present invention has been made in view of the above circumstances, and provides a polishing method, a method of manufacturing a piezoelectric vibrating piece, a piezoelectric vibrator, an oscillator, an electronic device, and a radio timepiece that can improve the thickness accuracy of a wafer during polishing. The purpose is that.

  In order to solve the above-described problems and achieve the object, a polishing method according to claim 1 of the present invention includes an upper surface plate (for example, an upper surface plate 151 in the embodiment) and a lower surface plate (for example, an implementation surface). A tuning fork wafer (for example, a quartz wafer (tuning fork substrate) 155 in the embodiment) held by a carrier (for example, the carrier 157 in the embodiment) with the lower surface plate 152) in the form. Then, an AT cut wafer for thickness measurement (for example, AT cut wafer 156 in the embodiment) is arranged on the carrier, the AT cut wafer is polished together with the tuning fork wafer, and the resonance of the AT cut wafer is achieved. The frequency is detected, and the thickness of the tuning fork wafer is controlled based on the detection result.

  Further, in the polishing method according to claim 2 of the present invention, after the polishing of the tuning fork wafer is started, the resonance frequency of the AT cut wafer corresponding to a desired thickness of the tuning fork wafer is determined a predetermined number of times within a predetermined time. When the above is detected, the polishing is finished.

  Furthermore, in the polishing method according to claim 3 of the present invention, at least one AT cut wafer is arranged at the center position of the carrier.

  Further, in the polishing method according to claim 4 of the present invention, when a plurality of tuning fork wafers are held on the carrier, the AT cut wafer is disposed between the adjacent tuning fork wafers.

  Furthermore, in the polishing method according to claim 5 of the present invention, the AT cut wafer is disk-shaped.

  According to a sixth aspect of the present invention, there is provided a piezoelectric vibrating piece for forming an electrode on a surface of a piezoelectric plate on which an outer shape of the piezoelectric vibrating piece is formed by using a photolithography technique (for example, A method of manufacturing a piezoelectric vibrating piece 5) according to an embodiment, comprising the step of polishing the piezoelectric plate by the polishing method according to any one of claims 1 to 5.

  A piezoelectric vibrator according to claim 7 of the present invention (for example, the piezoelectric vibrator 1 in the embodiment) includes the piezoelectric vibrating piece manufactured by the method of manufacturing a piezoelectric vibrating piece according to claim 6. Yes.

  In an oscillator according to claim 8 of the present invention (for example, the oscillator 100 in the embodiment), the piezoelectric vibrator according to claim 7 is electrically connected to an integrated circuit as an oscillator.

  Further, in an electronic device according to a ninth aspect of the present invention (for example, the portable information device 110 in the embodiment), the piezoelectric vibrator according to the seventh aspect is electrically connected to the time measuring unit.

  A radio timepiece according to claim 10 of the present invention (for example, the radio timepiece 130 in the embodiment) has the piezoelectric vibrator according to claim 7 electrically connected to the filter portion.

  According to the polishing method of the first aspect of the present invention, by detecting the resonance frequency of the AT cut wafer polished simultaneously with the tuning fork wafer and controlling the thickness of the tuning fork wafer based on the detection result, A tuning fork wafer can be easily finished to a desired thickness with high accuracy.

According to the polishing method of the present invention, the thickness accuracy of the tuning fork wafer can be improved.
In addition, it is possible to reduce the variation in thickness between the plurality of tuning fork wafers held for each carrier, and to reduce the variation in the thickness of the tuning fork wafer between the plurality of carriers.

  According to the polishing method of the third aspect of the present invention, the rotation balance between rotation and revolution can be improved for each carrier, and the parallelism of the tuning fork wafer can be improved.

  According to the polishing method of the fourth aspect of the present invention, the thickness accuracy of the tuning fork wafer can be improved.

  According to the polishing method of the fifth aspect of the present invention, the rotational balance of the AT cut wafer can be improved, and the thickness accuracy and parallelism of the tuning fork wafer can be improved.

  According to the method of manufacturing a piezoelectric vibrating piece according to claim 6 of the present invention, the thickness accuracy and parallelism of the tuning fork wafer can be improved, and the operation reliability of the piezoelectric vibrating piece can be improved.

  According to the piezoelectric vibrator, oscillator, electronic device, and radio timepiece of the present invention, the operation reliability can be improved.

1 is an external perspective view of a piezoelectric vibrator in an embodiment of the present invention. FIG. 2 is an internal configuration diagram of the piezoelectric vibrator shown in FIG. 1, and is a view of a piezoelectric vibrating piece viewed from above with a lid substrate removed. FIG. 3 is a cross-sectional view of the piezoelectric vibrator taken along line AA shown in FIG. 2. FIG. 2 is an exploded perspective view of the piezoelectric vibrator shown in FIG. 1. It is a perspective view of the metal pin used when manufacturing the piezoelectric vibrator shown in FIG. 2 is a flowchart showing a flow of manufacturing the piezoelectric vibrator shown in FIG. 1. It is a flowchart of the manufacturing process of a piezoelectric vibrating piece. It is a figure which shows the outline of the grinding | polishing apparatus of the crystal wafer (tuning fork substrate) which concerns on embodiment of this invention. It is the schematic which looked at the lower surface plate side from the upper surface plate side of the grinding | polishing apparatus of the crystal wafer (tuning fork substrate) which concerns on embodiment of this invention. It is the schematic which looked at the lower surface plate side from the upper surface plate side of the polishing apparatus of the crystal wafer (tuning fork substrate) which concerns on the modification of embodiment of this invention. It is process drawing for demonstrating the manufacturing method of a piezoelectric vibrator, Comprising: It is a disassembled perspective view of a wafer bonded body. (A)-(f) is a figure which shows the process of forming the penetration electrode with which the piezoelectric vibrator shown to FIG. 2 (a), (b) is equipped. 2A is a side view schematically showing a single-side polishing apparatus for polishing a metal pin in the step of forming the through electrode shown in FIGS. 2A and 2B. FIG. 2B is an upper surface plate from the lower surface plate side. It is the figure which looked at the side. (A) is a side view showing an outline of a double-side polishing apparatus for polishing a base substrate wafer in the step of forming a through electrode provided in the piezoelectric vibrator shown in FIGS. 2 (a) and 2 (b). It is the DD sectional view taken on the line of (a). It is a block diagram which shows one Embodiment of the oscillator which concerns on this invention. It is a block diagram which shows one Embodiment of the electronic device which concerns on this invention. It is a block diagram which shows one Embodiment of the radio timepiece which concerns on this invention.

  Hereinafter, a polishing method, a method of manufacturing a piezoelectric vibrating piece, a piezoelectric vibrator including the piezoelectric vibrating piece manufactured by the method of manufacturing the piezoelectric vibrating piece, an oscillator including the piezoelectric vibrator, and an electronic apparatus according to an embodiment of the invention The radio clock will be described.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Piezoelectric vibrator)
FIG. 1 is an external perspective view of the piezoelectric vibrator according to the present embodiment as viewed from the lid substrate side.
FIG. 2 is an internal configuration diagram of the piezoelectric vibrator, and is a view of the piezoelectric vibrating piece viewed from above with the lid substrate removed.
3 is a cross-sectional view of the piezoelectric vibrator taken along line AA shown in FIG. 2, and FIG. 4 is an exploded perspective view of the piezoelectric vibrator.

As shown in FIGS. 1 to 4, the piezoelectric vibrator 1 of the present embodiment includes a box-shaped package 10 in which a base substrate (first substrate) 2 and a lid substrate 3 are anodically bonded via a bonding material 23, A surface-mounted piezoelectric vibrator 1 including a piezoelectric vibrating piece (electronic component) 5 housed in a cavity C of a package 10.
Then, the piezoelectric vibrating reed 5 and the external electrodes 6, 7 installed on the back surface 2 a (the lower surface in FIG. 3: the first surface) of the base substrate 2 are formed by a pair of through electrodes 8, 9 penetrating the base substrate 2. Electrically connected.

The base substrate 2 is formed in a plate shape with a transparent insulating substrate made of a glass material, for example, soda-lime glass. The base substrate 2 is formed with a pair of through holes (recesses) 21 and 22 in which a pair of through electrodes 8 and 9 are formed.
The through-holes 21 and 22 have a taper-shaped cross section in which the diameter gradually decreases from the back surface 2a of the base substrate 2 toward the front surface 2b (upper surface in FIG. 3).

Similar to the base substrate 2, the lid substrate 3 is a transparent insulating substrate made of a glass material, for example, soda-lime glass, and is formed in a plate shape that can be superimposed on the base substrate 2.
A rectangular recess 3 a for accommodating the piezoelectric vibrating reed 5 is formed on the inner surface 3 b (lower surface in FIG. 3) side of the lid substrate 3.
The concave portion 3 a forms a cavity C that accommodates the piezoelectric vibrating piece 5 when the base substrate 2 and the lid substrate 3 are overlaid.

The lid substrate 3 is anodically bonded to the base substrate 2 via the bonding material 23 with the recess 3a facing the base substrate 2 side.
That is, the inner surface 3 b side of the lid substrate 3 constitutes a recess 3 a formed in the center and a frame region 3 c formed around the recess 3 a and serving as a bonding surface with the base substrate 2.

The piezoelectric vibrating piece 5 is a tuning fork type vibrating piece formed from a piezoelectric material such as quartz, lithium tantalate, or lithium niobate, and vibrates when a predetermined voltage is applied.
The piezoelectric vibrating reed 5 is a tuning fork type including a pair of vibrating arm portions 24 and 25 arranged in parallel and a base portion 26 that integrally fixes the base end sides of the pair of vibrating arm portions 24 and 25.

  And on the outer surface of a pair of vibrating arm parts 24 and 25, the excitation electrode which consists of a pair of 1st excitation electrode and the 2nd excitation electrode which are not shown in figure which vibrate the vibrating arm parts 24 and 25, and 1st The first and second excitation electrodes and a pair of mounting electrodes 27 and 28 to be described later are electrically connected (both not shown).

  2 and 3, the piezoelectric vibrating reed 5 configured as described above is bumped on the lead-out electrodes 27 and 28 formed on the surface 2b of the base substrate 2 by using the bump B such as gold. It is joined.

More specifically, the first excitation electrode of the piezoelectric vibrating piece 5 is bump-bonded on one lead-out electrode 27 via one mount electrode and bump B, and the second excitation electrode is connected to the other mount electrode and Bump bonding is performed on the other lead-out electrode 28 via the bump B.
As a result, the piezoelectric vibrating reed 5 is supported in a state of floating from the surface 2b of the base substrate 2, and the mount electrodes and the routing electrodes 27 and 28 are electrically connected to each other.

  The external electrodes 6 and 7 are installed on both sides in the longitudinal direction on the back surface 2 a of the base substrate 2, and are electrically connected to the piezoelectric vibrating reed 5 through the through electrodes 8 and 9 and the routing electrodes 27 and 28. ing.

More specifically, one external electrode 6 is electrically connected to one mount electrode of the piezoelectric vibrating piece 5 through one through electrode 8 and one routing electrode 27.
The other external electrode 7 is electrically connected to the other mount electrode of the piezoelectric vibrating piece 5 through the other through electrode 9 and the other lead-out electrode 28.

The through electrodes 8 and 9 were formed by firing a core material portion 31 disposed in the through holes 21 and 22 and a glass frit filled between the core material portion 31 and the through holes 21 and 22. It is comprised from the cylinder 32. FIG.
The through-electrodes 8 and 9 completely close the through-holes 21 and 22 to maintain airtightness in the cavity C, and have a role of conducting the external electrodes 6 and 7 and the lead-out electrodes 27 and 28.

  Specifically, one through electrode 8 is positioned below the lead-out electrode 27 between the external electrode 6 and the base portion 26, and the other through electrode 9 is between the external electrode 7 and the vibrating arm portion 25. Is located below the routing electrode 28.

The cylindrical body 32 is flat at both ends and is formed to have substantially the same thickness as the base substrate 2, and the outer shape of the cylindrical body 32 has a truncated cone shape (tapered cross section) according to the shape of the through holes 21 and 22. It is formed as follows.
Moreover, the cylinder 32 in this embodiment is comprised with the glass body 32a.

The glass body 32a is fired in a state in which a paste-like glass frit is embedded between the through holes 21 and 22 and the core member 31, and is firmly fixed to the through holes 21 and 22. Has been.
Specifically, the glass body 32 a is formed so as to fill the through holes 21 and 22 over almost the entire region in the thickness direction of the base substrate 2.

In this case, the end face on one end side in the thickness direction of the glass body 32 a is formed flush with the surface 2 b of the base substrate 2 and is exposed in the cavity C together with the core part 31.
On the other hand, the end surface on the other end side in the thickness direction of the glass body 32 a is formed flush with the back surface 2 a of the base substrate 2 and is exposed to the outside together with the core member 31.
And the core part 31 is distribute | arranged to the center of the cylinder 32 (glass body 32a) so that the center hole of the cylinder 32 may be penetrated.

  The core part 31 described above is a conductive material formed in a cylindrical shape by a metal material (α = 6 to 7 ppm) having a thermal expansion coefficient α smaller than that of the glass frit, such as an Fe—Ni alloy (42 alloy). It is a core material, and is formed so that both ends are flat and the thickness of the base substrate 2 is substantially the same as the cylindrical body 32.

When the through electrodes 8 and 9 are formed as finished products, the core portion 31 is formed in a columnar shape and has the same thickness as the base substrate 2 as described above. In the process, for example, as shown in FIG. 5, a box-shaped metal pin 37 is formed together with a flat base portion 36 connected to one end portion of the core portion 31.
Further, the base portion 36 is polished and removed in the manufacturing process (described later in the manufacturing method).
The through electrodes 8 and 9 are ensured to have electrical conductivity through the conductive core portion 31.

A bonding material 23 for anodic bonding is formed on the entire inner surface 3 b of the lid substrate 3.
Specifically, the bonding material 23 is formed over the entire inner surface of the frame region 3c and the recess 3a.
Although the bonding material 23 of the present embodiment is formed of a Si film, the bonding material 23 can also be formed of Al.
As the bonding material 23, a Si bulk material whose resistance is reduced by doping or the like can be used.
As will be described later, the bonding material 23 and the base substrate 2 are anodically bonded, and the cavity C is vacuum-sealed.

When the piezoelectric vibrator 1 configured as described above is operated, a predetermined drive voltage is applied to the external electrodes 6 and 7 formed on the base substrate 2.
As a result, a current can flow through each excitation electrode of the piezoelectric vibrating piece 5, and the pair of vibrating arm portions 24 and 25 can be vibrated at a predetermined frequency in a direction in which the pair of vibrating arm portions 24 and 25 approaches or separates.
The vibration of the pair of vibrating arm portions 24 and 25 can be used as a time source, a control signal timing source, a reference signal source, or the like.

(Package manufacturing method)
Next, a method for manufacturing a package (piezoelectric vibrator) containing the above-described piezoelectric vibrating piece will be described with reference to the flowcharts shown in FIGS.
6 and 7 are flowcharts of the method for manufacturing the piezoelectric vibrator according to the present embodiment.
8 to 10 are diagrams showing a polishing apparatus for a piezoelectric vibrator substrate.
FIG. 11 is an exploded perspective view of the wafer bonded body.

Hereinafter, a plurality of piezoelectric vibrating reeds 5 are encapsulated between a base substrate wafer 40 in which a plurality of base substrates 2 are connected and a lid substrate wafer 50 in which a plurality of lid substrates 3 are connected to form a wafer bonded body 60. A method for simultaneously manufacturing a plurality of piezoelectric vibrators 1 by cutting the wafer bonded body 60 will be described.
In addition, the broken line M shown in FIG. 11 shows the cutting line cut | disconnected by a cutting process.

As shown in FIG. 6, the piezoelectric vibrator manufacturing method according to the present embodiment mainly includes a piezoelectric vibrating piece manufacturing step (S01), a base substrate wafer manufacturing step (S10), and a lid substrate wafer manufacturing step. (S30) and an assembly process (S50 and below).
Among these, the piezoelectric vibrating reed manufacturing step (S10), the lid substrate wafer manufacturing step (S30), and the base substrate wafer manufacturing step (S10) can be performed in parallel.

(Method for manufacturing piezoelectric vibrating piece)
First, the piezoelectric vibrating reed manufacturing step is performed to manufacture the piezoelectric vibrating reed 5 (S01).
Further, after the piezoelectric vibrating piece 5 is manufactured, the resonance frequency is coarsely adjusted.
Note that fine adjustment for adjusting the resonance frequency with higher accuracy is performed after mounting.

The manufacturing process of the piezoelectric vibrating reed 5 of the present embodiment mainly includes an outer shape forming step S210 for forming a plurality of outer shapes of the piezoelectric vibrating reed 5 on a crystal wafer (piezoelectric plate), and an electrode forming step for forming each electrode on the crystal wafer. S220, the frequency adjustment process S230 which adjusts a resonant frequency, and the fragmentation process S240 which separates a some piezoelectric vibrating piece from one crystal wafer are provided.
Details of each step will be described below.

(Outline forming step S210)
First, an outer shape forming step S210 for forming a plurality of outer shapes of the piezoelectric vibrating reed 5 on a quartz wafer is performed.
Specifically, a quartz wafer that has been polished and finished to a predetermined thickness with high accuracy is prepared.
Next, the quartz wafer is etched by a photolithography technique to form a plurality of external shapes of the piezoelectric vibrating reed 5 on the quartz wafer.
Thus, the outer shape forming step S210 is completed.

  Note that a polishing apparatus 150 that finishes a tuning-fork crystal wafer (tuning fork substrate) to a predetermined thickness with high accuracy includes an upper surface plate 151 and an upper surface plate 151 having a circular shape in plan view, as shown in FIGS. The lower surface plate 152 having the same circular shape in plan view, the sun gear 153 rotatably provided at the center of the lower surface plate 152, the internal gear 154 surrounding the outer periphery of the lower surface plate 152, the upper surface plate 151, and the lower surface plate 152 Between the sun gear 153 and the internal gear 154, and rotates and revolves in cooperation with the sun gear 153 and the internal gear 154, and a tuning fork crystal wafer (tuning fork substrate) 155 and an AT cut wafer A plurality of carriers 157 holding 156, a probe 158 for measuring the resonance frequency of the AT cut wafer 156, an upper surface plate 151, and a lower surface plate 152. And the sun gear 153, a rotating means for rotating each of the internal gear 154 (e.g., such as a driver head 160 to rotate the upper platen 151), is schematically composed.

The upper surface plate 151 and the lower surface plate 152 are concentric and rotate in the horizontal direction.
Teeth are vertically and annularly arranged at a constant pitch on the outer periphery of the sun gear 153 and the inner periphery of the internal gear 154.
The sun gear 153 and the internal gear 154 are concentric with the upper surface plate 151 and the lower surface plate 152 and rotate in the horizontal direction.
In this embodiment, a double-side polishing apparatus in which the internal gear 154 rotates independently is used. However, the internal gear 154 does not rotate independently, but is fixed to the lower surface plate 152 and rotates together with the lower surface plate 152, for example. A double-side polishing apparatus having a structure may be used.

The carrier 157 has a disk shape, and includes a plurality of holding holes in which a quartz wafer (tuning fork substrate) 155 and an AT cut wafer 156 are fitted and held.
The carrier 157 is thinner than the quartz wafer (tuning fork substrate) 155 and the AT cut wafer 156, and the quartz wafer so that the quartz wafer (tuning fork substrate) 155 and the AT cut wafer 156 protrude from above and below the carrier 157. (Tuning fork substrate) 155 and the side surfaces of the AT cut wafer 156 are held.

Further, teeth are arranged vertically and annularly at a constant pitch on the outer periphery of the carrier 157.
The carrier 157 is not fixed, and the carrier 157 rotates and revolves when the teeth of the carrier 157 mesh with the teeth of the rotating sun gear 153 and the internal gear 154.

  Each carrier 157 has one disc-shaped AT cut wafer 156 disposed at the center position of the carrier 157, and a plurality of (for example, four) discs so as to surround the AT cut wafer 156. , 155 are arranged.

  The upper surface plate 151 has, for example, a position that can be opposed to the AT cut wafer 156 held by each carrier 157 (for example, a position that is opposed to the rotation trajectory of the center position of each carrier 157). The probe 158 for measuring the resonance frequency of the AT cut wafer 156 is disposed at a position shifted from the rotation axis 151.

  For example, the probe 158 is mounted in a through hole (not shown) penetrating the upper surface plate 151 in the thickness direction, insulated from the upper surface plate 151, and the detection electrode and the lower surface plate. A sweep oscillator (not shown) that applies a high-frequency voltage that changes in frequency with time between the AT 152 and the AT cut wafer 156 exists immediately below the detection electrode, and is applied to the resonance frequency of the AT cut wafer 156 and the sweep oscillator. And a detection circuit (not shown) that detects a decrease in the apparent impedance of the AT cut wafer 156 when the frequency of the generated high-frequency voltage matches.

In the polishing method for the quartz wafer (tuning fork substrate) 155, first, the quartz wafer (tuning fork substrate) 155 and the AT cut wafer 156 are placed in the holding holes of the carrier 157.
Then, the upper surface plate 151, the lower surface plate 152, the sun gear 153, and the internal gear 154 are rotated while supplying abrasives to the upper and lower surfaces of the crystal wafer (tuning fork substrate) 155 and the AT cut wafer 156, respectively. The carrier 157 holding the substrate 155 and the AT cut wafer 156 is also rotated and revolved.

Then, the quartz wafer (tuning fork substrate) 155 and the AT cut wafer 156 held on the carrier 157 are polished by polishing adhered to the upper surface plate 151 and the lower surface plate 152.
At this time, since the carrier 157 performs planetary motion, the AT cut wafer 156 is positioned immediately below the detection electrode of the probe 158 at an appropriate time interval.

Therefore, after the polishing of the quartz wafer (tuning fork substrate) 155 and the AT cut wafer 156 is started, the resonance frequency of the AT cut wafer 156 is measured by the probe 158 to correspond to the desired thickness of the quartz wafer (tuning fork substrate) 155. The resonance frequency of the AT cut wafer 156 (that is, the finished thickness of the AT cut wafer 156 corresponding to the desired finished thickness of the crystal wafer (tuning fork substrate) 155 when the quartz wafer (tuning fork substrate) 155 and the AT cut wafer 156 are polished simultaneously). The resonance frequency of the AT-cut wafer 156 corresponding to is detected a predetermined number of times (for example, an appropriate number of times of 3 to 5) within a predetermined time (for example, an appropriate time of 0.5 s to 1.0 s). In this case, the polishing is finished.
In this way, the production process of the quartz wafer (tuning fork substrate) 155 having a predetermined thickness is completed.

  When a plurality of (for example, four) disk-shaped crystal wafers (tuning fork substrates) 155,..., 155 are arranged on each carrier 157, for example, as shown in FIG. An AT cut wafer 156 may be disposed between the wafers (tuning fork substrates) 155 and 155.

(Electrode forming step S220)
Next, an electrode forming step S <b> 220 is performed in which each of the excitation electrode, the extraction electrode, and the mount electrode (all not shown) is formed on the surface of the crystal wafer on which the outer shape of the piezoelectric vibrating piece 5 is formed.
The electrode forming step S220 includes a metal film forming step S221 for forming a metal film on the surface of the quartz wafer, and a photoresist applying step S223 for applying a photoresist (mask material) on the metal film (mask material applying step). An exposure step S225 for exposing the photoresist, a development step S227 for selectively removing the photoresist to form a mask pattern, and an etching step for etching the metal film through the mask pattern to form each electrode. S229.

(Metal film forming step S221)
In the electrode forming step S220, first, a metal film forming step S221 for forming a metal film to be an excitation electrode later on the quartz wafer is performed.
In this embodiment, chromium having good adhesion to the crystal is formed on the surface of the crystal wafer by several μm by sputtering or vacuum deposition.
Further, it is formed by applying a gold thin film as a finishing layer from above the chromium film.
The excitation electrode and the extraction electrode are formed of a single layer film made of only chromium, and the mount electrode is formed of a laminated film of chromium and gold.

(Photoresist coating step S223)
Subsequently, a photoresist coating step S223 is performed in which a photoresist is coated over the metal film.
As described above, the photoresist includes a positive resist in which the exposed portion is softened and removed, and a negative resist in which the exposed portion remains, but in this embodiment, a positive resist is used. It is applied.
The photoresist is applied to the entire surface of the quartz wafer by being overlaid on the metal film by spray coating, spin coating, or the like.

(Exposure step S225)
In the exposure step S225, a photomask having an opening is set facing the photoresist, and the photoresist is irradiated with ultraviolet rays through the opening.
The opening of the photomask is a region where the photoresist is desired to be removed, and is formed corresponding to a region where the electrode film is desired to be removed in an etching step S229 described later. In other words, the opening of the photomask is formed corresponding to a region where the excitation electrode, extraction electrode, and mount electrode (all not shown) are not formed.
When the exposure is completed, the photomask is removed.

After the exposure step S225, a development step S227 for selectively removing the photoresist to form a mask pattern is performed.
In the developing step S227, the quartz wafer coated with the photoresist is immersed in a developer stored in a water tank (not shown) to selectively remove the photoresist, thereby forming a resist pattern (mask pattern).

  Specifically, in the development step S227, the photoresist corresponding to the region exposed to the ultraviolet ray through the opening of the photomask, that is, the region where the excitation electrode, the extraction electrode, and the mount electrode are not formed is removed. ing.

(Washing step S228)
Subsequently, a cleaning step S228 for washing away the developer remaining on the quartz wafer in the developing step S227 is performed.
In the cleaning step S228, the developer remaining on the surface of the crystal wafer is washed away by immersing the crystal wafer in pure water stored in a water tank (not shown) and swinging the crystal wafer in the pure water.

(Etching step S229)
Next, etching is performed using the resist pattern as a mask, and an etching step S229 for forming each electrode is performed.
In this step, the metal film masked by the resist pattern is left, and the metal film not masked by the resist pattern is selectively removed.
By the etching step S229, the excitation electrode, the extraction electrode, and the mount electrode of the piezoelectric vibrating piece 5 are formed.

(Frequency adjustment step S230)
Next, as shown in FIG. 1, a weight metal film (for example, silver, gold, or the like) made of a frequency adjustment coarse adjustment film and a fine adjustment film is formed at the tips of the pair of vibrating arm portions 24 and 25.
Then, a frequency adjustment step S230 for roughly adjusting the resonance frequency is performed on all the vibrating arm portions 24 and 25 formed on the quartz wafer.
This is done by irradiating the coarse adjustment film of the weight metal film with laser light to evaporate a part thereof and changing the weight.
The fine adjustment for adjusting the resonance frequency with higher accuracy is performed in the state of the piezoelectric vibrator 1.
Above, frequency adjustment process S230 is complete | finished.

(Smallization step S240)
Finally, a connecting portion that connects the crystal wafer and the piezoelectric vibrating piece 5 is cut, and a fragmentation step S240 is performed to separate the plurality of piezoelectric vibrating pieces 5 from the crystal wafer into pieces.
Thereby, a plurality of tuning fork type piezoelectric vibrating reeds 5 can be manufactured at a time from one crystal wafer.
At this point, the manufacturing process of the piezoelectric vibrating piece 5 is completed, and a plurality of piezoelectric vibrating pieces 5 can be obtained.

(Base substrate wafer creation process)
Hereinafter, a process of manufacturing the base substrate wafer 40 to be the base substrate 2 will be described.
First, a step of manufacturing a base substrate wafer 40 to be the base substrate 2 later is performed (S10).
First, a disk-shaped base substrate wafer 40 as shown in FIG. 11 is formed.
Specifically, after polishing and cleaning soda-lime glass to a predetermined thickness, the work-affected layer on the outermost surface is removed by etching or the like (S11).
In addition, a dotted line M in FIG. 11 illustrates a cutting line for cutting the base substrate wafer 40 in a subsequent cutting process.

(Penetration electrode formation process)
Subsequently, a through electrode forming process for forming the through electrodes 8 and 9 on the base substrate wafer 40 is performed (S10A).
Details of the through electrode forming step will be described below.

First, as shown in FIG. 12A, a plurality of pairs of through holes 21 and 22 penetrating the base substrate wafer 40 are formed (S12).
The through holes 21 and 22 are formed by, for example, a sand blast method or press working. In the sandblasting method or press working, the through holes 21 and 22 can be formed in a tapered shape.
At this time, the through holes 21 and 22 are tapered such that the diameter gradually decreases from the lower surface (outside of the base substrate 2) of the base substrate wafer 40 toward the upper surface (cavity C side).

Subsequently, the core portion 31 of the metal pin 37 is inserted from the upper side with the central axis aligned in the through holes 21 and 22, and the base portion 36 of the metal pin 37 and the base substrate wafer 40 are brought into contact with each other to be turned upside down. (S13).
At this time, as shown in FIG. 12 (b), the through holes 21 and 22 are such that the taper shape gradually decreases in diameter toward the lower side, and the metal pin 37 is located above the base portion 36 and the core portion 31. Is arranged in the direction in which is located.
At this time, the planar shape of the base portion 36 is larger than the openings of the small diameter sides 21a and 22a of the through holes 21 and 22, and the openings of the small diameter sides 21a and 22a can be closed.

  Then, as shown in FIG. 12 (c), the gap between the through holes 21 and 22 and the core part 31 is filled with a paste-like glass frit forming a glass body 32a (S14), and the glass is fired at a predetermined temperature. The frit is solidified to form a glass body 32a (S15).

Thus, by bringing the base portion 36 into contact with the surface of the base substrate wafer 40, the paste-like glass frit can be reliably filled in the through holes 21 and 22.
Further, since the base portion 36 is formed in a flat plate shape, the metal pins 37 and the base substrate wafer 40 on which the metal pins 37 are installed are stable without rattling or the like, so that the workability is improved. Can be planned.
Then, the glass frit is baked and solidified to form a glass body 32a, fixing the metal pin 37 in a close contact state, and adhering to the through holes 21 and 22 to seal the through holes 21 and 22. .

Subsequently, the base portion 36 of the metal pin 37 is polished and removed (S16).
Polishing of the base part 36 is performed using a single-side polishing apparatus 51 as shown in FIGS.

  The single-side polishing apparatus 51 is arranged in a plurality of positions on the upper surface plate 52 having a circular shape in plan view, a lower surface plate 53 having a circular shape in the same plan view as the upper surface plate 52, and a base substrate wafer. A carrier 54 having a circular shape in plan view for adsorbing and fixing 40, an abrasive inflow means 55 for flowing an abrasive 56 between the upper surface plate 52 and the lower surface plate 53, an upper surface plate 52, a lower surface plate 53 and a carrier 54 Rotating means (not shown) for rotating each of them.

The lower surface plate 53 is formed of a solid surface plate without grooves, and has a structure that rotates in the horizontal direction in the direction of arrow A1 in the drawing.
The carrier 54 has a structure that is rotatably held in the horizontal direction on the upper surface plate 52 and rotates in the direction of an arrow A2 in the drawing. In this way, the structure in which the lower surface plate 53 rotates and the carrier 54 rotates allows the surface to be polished flatly without any decrease in the polishing surface.
In the step of polishing the base portion 36, the rotational speed of the lower surface plate 53 is 15 rpm, and the rotational speed of the carrier 54 is 45 rpm.

  The abrasive inflow means 55 conveys the abrasive 56 in the accommodating portion, which contains the motor 56 for containing and stirring the abrasive 56, and lowers from the inlet 55a provided in the upper surface plate 52 at about 6 to 8 locations. A pump that flows onto the board 53 and a PH measuring device that measures the pH of the abrasive 56 are provided. In the single-side polishing apparatus 51, polishing is performed while supplying the abrasive 56, and the flow rate of the abrasive 56 flowing into the lower surface plate 53 from the inflow port 55a is set to a predetermined flow rate.

The polishing method of the base portion 36 of the metal pin 37 is as follows. First, the base substrate wafer 40 is attracted and fixed to the carrier 54 so that the base portion 36 protruding from the base substrate wafer 40 is on the lower side. Install in.
At this time, a flat dummy substrate 57 made of, for example, glass epoxy resin (FR4) is installed below the upper surface plate 52 or the carrier 54.
The dummy substrate 57 has a thickness such that the lower end portion is located below the lower end portion of the base portion 36.

Then, while supplying the polishing agent 56, the lower surface plate 53 and the carrier 54 are each rotated by a rotating means to perform polishing. At this time, polishing is performed by applying a pressure of 15 to 50 g / cm ^{2 in} the direction from the upper surface plate 52 to the lower surface plate 53.
The dummy substrate 57 comes into contact with the lower surface plate 53 before the base portion 36 and the dummy substrate 57 is polished, and thereafter the base portion 36 comes into contact with the lower surface plate 53 and is polished together with the dummy substrate 57.

As described above, the dummy substrate 57 is polished before the base portion 36, and then the base portion 36 is polished together with the dummy substrate 57, so that pressure is gradually applied from the lower surface plate 53 to the base substrate wafer 40. It becomes possible to load, and damage to the base substrate wafer 40 can be prevented.
In this way, the base part 36 is removed, and only the core part 31 is left inside the cylindrical body 32 as shown in FIG.

Then, the process of grind | polishing the glass surface 40a of the wafer 40 for base substrates from which the base part 36 was removed is performed (S17).
The step of polishing the glass surface 40a is mainly for flattening the frit glass that has been dented by firing. For example, double-side polishing for polishing both front and back surfaces of a thin wafer such as glass or ceramic. Use the device.

  As shown in FIGS. 14A and 14B, the double-side polishing apparatus 71 includes an upper surface plate 72 having a circular shape in plan view, a lower surface plate 73 having the same circular shape in plan view as the upper surface plate 72, and a lower surface plate 73. Between the sun gear 74 and the internal gear 75, between the sun gear 74 and the internal gear 75, and between the sun gear 74 and the internal gear 75. A plurality of carriers 76 for holding the substrate wafer 40, an abrasive inflow means 78 for introducing an abrasive 77 into both surfaces of the base substrate wafer 40, an upper surface plate 72, a lower surface plate 73, a sun gear 74, and an internal gear 75. Rotating means (not shown) for rotating each of them.

The upper surface plate 72 and the lower surface plate 73 are concentric and rotate in the horizontal direction. In the step of polishing the glass surface 40a of the base substrate wafer 40, the rotational speed of the upper surface plate 72 is 45 rpm, and the rotational speed of the lower surface plate 73 is 15 rpm.
Polishing pads 79 and 80 are attached to the polishing side surfaces of the upper surface plate 72 and the lower surface plate 73. For example, a polishing pad made of cerium oxide is used.

On the outer periphery of the sun gear 74 and the inner periphery of the internal gear 75, teeth 74a, 75a are vertically and annularly arranged at a constant pitch. The sun gear 74 and the internal gear 75 are concentric with the upper surface plate 72 and the lower surface plate 73 and rotate in the horizontal direction.
In the present embodiment, the double-side polishing apparatus 71 in which the internal gear 75 rotates independently is used. However, the internal gear does not rotate independently, and is fixed to the lower surface plate, for example, and rotates together with the lower surface plate. A double-side polishing apparatus may be used.

The carrier 76 has a disk shape and includes a plurality of base substrate wafer holding holes 76b in which the base substrate wafer 40 is fitted and held.
The carrier 76 has a thickness smaller than that of the base substrate wafer 40 and holds the side surface of the base substrate wafer 40 so that the base substrate wafer 40 protrudes from above and below the carrier 76.

On the outer periphery of the carrier 76, teeth 76a are vertically and annularly arranged at a constant pitch.
The carrier 46 is not fixed, and the carrier 76 rotates and revolves when the teeth 76a of the carrier 76 mesh with the rotating sun gear 74 and the teeth 74a and 75a of the internal gear 75.

  The abrasive inflow means 78 conveys the abrasive 77 in the accommodating portion (not shown) having a motor for accommodating and stirring the abrasive 77, and the base from the inlet 78a provided at about eight places on the upper surface plate 52. A pump (not shown) for allowing the abrasive 77 to flow into the upper and lower surfaces of the substrate wafer 40.

The abrasive inflow means 78 includes an abrasive recovery unit 81 that recovers the abrasive 77 flowing out from the lower surface plate 73. The recovered abrasive 77 can be conveyed again to the inlet 78a. .
In the step of polishing the glass surface 40a of the base substrate wafer 40, the flow rate of the abrasive 77 flowing into the upper and lower surfaces of the base substrate wafer 40 from the inlet 78a is set to about 10 L / min.
As the polishing agent 77, cerium oxide or the like generally used for polishing a glass surface is used.

In the method of polishing the glass surface 40 a of the base substrate wafer 40, first, the base substrate wafer 40 from which the base portion 36 has been removed is placed in the base substrate wafer holding hole 76 b of the carrier 76.
Then, while supplying the polishing agent 77 to the upper and lower surfaces of the base substrate wafer 40, the upper surface plate 72, the lower surface plate 73, the sun gear 74, and the internal gear 75 are rotated to respectively support the carrier 76 that holds the base substrate wafer 40. Also rotate and revolve.

Then, the glass surface 40 a of the base substrate wafer 40 held by the carrier 76 is polished by the polishing pads 79 and 80 attached to the upper surface plate 72 and the lower surface plate 73.
At this time, polishing is performed by applying a pressure of 100 to 500 g / cm ^{2 in} the direction from the upper surface plate 72 to the lower surface plate 73.

Subsequently, a step of polishing the core part 31 protruding from the base substrate wafer 40 is performed (S18).
The core material portion 31 is polished one surface at a time by the single-side polishing device 51 in the same manner as the method for polishing the base portion 36 of the metal pin 37 described above.
At this time, the polishing is performed by bringing the core part 31 and the lower surface plate 53 into contact with each other without using the dummy substrate 57 used for polishing the base part 36.
Thus, by polishing the core part 31 one side at a time, the upper and lower polishing amounts can be made uniform.

Also, the polishing of the core material portion 31 may be performed only on the surface that will later become the cavity C side without performing both surfaces.
And after grind | polishing the part which the core material part 31 protruded, as shown in FIG.12 (e) to FIG.12 (f), the glass surface 40a of the wafer 40 for base substrates, the surface of the penetration electrodes 8 and 9, However, it becomes a substantially flush state.
In this way, the through electrodes 8 and 9 are formed on the base substrate wafer 40.

Next, a conductive material is patterned on the upper surface of the base substrate wafer 40 to perform a bonding film forming process for forming a bonding film (S19), and a routing electrode forming process is performed (S20).
In this way, the manufacturing process of the base substrate wafer 40 is completed.

(Wad production process for lid substrate)
Next, a lid substrate wafer manufacturing process is performed in which a lid substrate wafer 50 to be the lid substrate 3 later is manufactured up to the state immediately before anodic bonding at the same time as or before and after the manufacture of the base substrate 2 (S30). .
In the process of manufacturing the lid substrate 3, first, a disk-shaped lid substrate wafer to be the lid substrate 3 is formed first.

Specifically, after polishing and cleaning soda-lime glass to a predetermined thickness, the work-affected layer on the outermost surface is removed by etching or the like (S31).
Next, the recess 3a for the cavity C is formed on the lid substrate wafer by etching or pressing (S32).

  Next, in order to ensure airtightness with the base substrate wafer 40 to be described later, a polishing step of polishing at least the first surface 50a side of the lid substrate wafer 50 that is a bonding surface with the base substrate wafer 40. (S33) is performed, and the first surface 50a is mirror-finished.

Next, a bonding material forming step (S34) is performed in which the bonding material 23 is formed on the entire first surface 50a of the lid substrate wafer 50 (the bonding surface with the base substrate wafer 40 and the inner surface of the recess 3a).
In this manner, by forming the bonding material 23 on the entire first surface 50a of the lid substrate wafer 50, patterning of the bonding material 23 becomes unnecessary, and the manufacturing cost can be reduced.

The bonding material 23 can be formed by a film forming method such as sputtering or CVD.
Further, since the bonding surface is polished before the bonding material forming step (S34), the flatness of the surface of the bonding material 23 is ensured, and stable bonding with the base substrate wafer 40 can be realized.
Thus, the lid substrate wafer creation step (S30) is completed.

(Assembly process)
Next, the piezoelectric vibrating reed 5 created in the piezoelectric vibrating reed creating step (S01) is bumped onto a lead electrode 27 of the base substrate wafer 40 created in the base substrate wafer creating step (S10) with a bump such as gold. Mount via B (S50).
Then, an overlaying step is performed in which the base substrate wafer 40 and the lid substrate wafer 50 created in each of the wafer creation steps described above are overlaid (S60).

Specifically, the base substrate wafer 40 and the lid substrate wafer 50 are aligned at correct positions while using a reference mark or the like (not shown) as an index.
As a result, the mounted piezoelectric vibrating reed 5 is housed in a cavity C surrounded by the recess 3 a formed in the lid substrate wafer 50 and the base substrate wafer 40.

  After the superimposing step (S60), the two superposed base substrate wafers 40 and the lid substrate wafer 50 are put into an anodic bonding apparatus (not shown), and the outer peripheral portion of the wafer is clamped by a holding mechanism (not shown), A joining step is performed in which a predetermined voltage is applied in the temperature atmosphere to perform anodic bonding (S70).

Specifically, a predetermined voltage is applied between the bonding material 23 and the lid substrate wafer 50.
As a result, an electrochemical reaction occurs at the interface between the bonding material 23 and the lid substrate wafer 50, and the two are firmly bonded and anodically bonded.
Thereby, the piezoelectric vibrating reed 5 can be sealed in the cavity C, and the wafer bonded body 60 in which the base substrate wafer 40 and the lid substrate wafer 50 are bonded can be obtained.

  Then, as in this embodiment, the lid substrate wafer 50 and the base substrate wafer 40 are anodically bonded to each other, so that the lid substrate wafer 50 and the base substrate wafer 40 are bonded with an adhesive or the like. The lid substrate wafer 50 and the base substrate wafer 40 can be more firmly bonded to each other by preventing the deterioration due to aging, impact, etc., warpage of the wafer bonded body 60, and the like.

Thereafter, a pair of external electrodes 6 and 7 electrically connected to the pair of through electrodes 8 and 9 are formed (S80), and the frequency of the piezoelectric vibrator 1 is finely adjusted (S90).
And the cutting process (S100) which cut | disconnects the bonded wafer bonded body 60 along the cutting line M, and divides it into pieces.

In the electrical characteristic inspection step (S110), the resonance frequency, resonance resistance value, drive level characteristic (excitation power dependency of the resonance frequency and resonance resistance value), etc. of the piezoelectric vibrator 1 are measured and checked. In addition, the insulation resistance characteristics are also checked.
Finally, an appearance inspection of the piezoelectric vibrator 1 is performed to finally check dimensions, quality, and the like.
Thus, the piezoelectric vibrator 1 is completed.

According to the polishing method of the present embodiment described above, the resonance frequency of the AT cut wafer 156 that is simultaneously polished with the quartz wafer (tuning fork substrate) 155 is detected, and the quartz wafer (tuning fork substrate) 155 is detected based on the detection result. By controlling the thickness, the quartz wafer (tuning fork substrate) 155 can be easily finished with a desired thickness with high accuracy.
In addition, it is possible to reduce the variation in thickness between the plurality of quartz wafers (tuning fork substrates) 155 held for each carrier 157, and to vary the thickness of the quartz wafer (tuning fork substrate) 155 between the plurality of carriers 157. Can be reduced.

Further, the AT-cut wafer 156 is arranged at the center position of the carrier 157, or when a plurality of disc-shaped crystal wafers (tuning fork substrates) 155,. By arranging the AT cut wafer 156 between the quartz wafers (tuning fork substrates) 155 and 155, the rotational balance of rotation and revolution can be improved for each carrier 157, and the parallelism of the quartz wafer (tuning fork substrate) 155 is improved. Can be improved.
Furthermore, by making the AT cut wafer 156 into a disk shape, the rotational balance of the AT cut wafer 156 can be improved, and the thickness accuracy and parallelism of the quartz wafer (tuning fork substrate) 155 can be improved.

  Furthermore, according to the method of manufacturing the piezoelectric vibrating piece according to the above-described embodiment, the thickness accuracy and parallelism of the quartz wafer 155 quartz wafer (tuning fork substrate) 155 can be improved, and the operation reliability of the piezoelectric vibrating piece 5 can be improved. Can be improved.

  Furthermore, according to the piezoelectric vibrator 1 according to the present embodiment described above, the operation reliability can be improved.

(Oscillator)
Next, an embodiment of an oscillator according to the present invention will be described with reference to FIG.
As shown in FIG. 15, the oscillator 100 according to the present embodiment is configured by configuring the piezoelectric vibrator 1 as an oscillator electrically connected to the integrated circuit 101.
The oscillator 100 includes a substrate 103 on which an electronic component 102 such as a capacitor is mounted.
On the substrate 103, the integrated circuit 101 for the oscillator is mounted, and the piezoelectric vibrator 1 is mounted in the vicinity of the integrated circuit 101.
The electronic component 102, the integrated circuit 101, and the piezoelectric vibrator 1 are electrically connected by a wiring pattern (not shown).
Each component is molded with a resin (not shown).

In the oscillator 100 configured as described above, when a voltage is applied to the piezoelectric vibrator 1, the piezoelectric vibrating piece 5 in the piezoelectric vibrator 1 vibrates.
This vibration is converted into an electric signal by the piezoelectric characteristics of the piezoelectric vibrating piece 5 and input to the integrated circuit 101 as an electric signal.
The input electrical signal is subjected to various processes by the integrated circuit 101 and is output as a frequency signal. Thereby, the piezoelectric vibrator 1 functions as an oscillator.
Further, by selectively setting the configuration of the integrated circuit 101, for example, an RTC (real-time clock) module or the like according to a request, the operation date and time of the device and external device in addition to a single-function oscillator for a clock A function for controlling the time, providing a time, a calendar, and the like can be added.

  As described above, according to the oscillator 100 of the present embodiment, the piezoelectric vibrating piece 5 is made of the quartz crystal wafer (tuning fork substrate) 155 with improved thickness accuracy and parallelism. 5 can be improved, and the reliability of the operation can be improved to improve the quality.

(Electronics)
Next, an embodiment of an electronic apparatus according to the present invention will be described with reference to FIG.
Note that the portable information device 110 having the above-described piezoelectric vibrator 1 will be described as an example of the electronic device.
First, the portable information device 110 according to the present embodiment is represented by, for example, a mobile phone, and is a development and improvement of a wrist watch in the related art.
The appearance is similar to that of a wristwatch, and a liquid crystal display is arranged in a portion corresponding to a dial so that the current time and the like can be displayed on this screen.
Further, when used as a communication device, it is possible to perform communication similar to that of a conventional mobile phone by using a speaker and a microphone that are removed from the wrist and incorporated in the inner portion of the band.
However, it is much smaller and lighter than conventional mobile phones.

Next, the configuration of the portable information device 110 of this embodiment will be described.
As shown in FIG. 16, the portable information device 110 includes the piezoelectric vibrator 1 and a power supply unit 111 for supplying power.
The power supply unit 111 is made of, for example, a lithium secondary battery.
The power supply unit 111 includes a control unit 112 that performs various controls, a clock unit 113 that counts time, a communication unit 114 that communicates with the outside, a display unit 115 that displays various types of information, A voltage detection unit 116 that detects the voltage of the functional unit is connected in parallel.
The power unit 111 supplies power to each functional unit.

The control unit 112 controls each function unit to control operation of the entire system such as transmission and reception of audio data, measurement and display of the current time, and the like.
The control unit 112 includes a ROM in which a program is written in advance, a CPU that reads and executes the program written in the ROM, and a RAM that is used as a work area of the CPU.

The timer unit 113 includes an integrated circuit including an oscillation circuit, a register circuit, a counter circuit, an interface circuit, and the like, and the piezoelectric vibrator 1.
When a voltage is applied to the piezoelectric vibrator 1, the piezoelectric vibrating piece 5 vibrates, and the vibration is converted into an electric signal by the piezoelectric characteristics of the crystal, and is input to the oscillation circuit as an electric signal.
The output of the oscillation circuit is binarized and counted by a register circuit and a counter circuit.
Then, signals are transmitted to and received from the control unit 112 via the interface circuit, and the current time, current date, calendar information, or the like is displayed on the display unit 115.

The communication unit 114 has functions similar to those of a conventional mobile phone, and includes a radio unit 117, a voice processing unit 118, a switching unit 119, an amplification unit 120, a voice input / output unit 121, a telephone number input unit 122, and a ring tone generation unit. 123 and a call control memory unit 124.
The wireless unit 117 exchanges various data such as audio data with the base station via the antenna 125.

The audio processing unit 118 encodes and decodes the audio signal input from the radio unit 117 or the amplification unit 120.
The amplifying unit 120 amplifies the signal input from the audio processing unit 118 or the audio input / output unit 121 to a predetermined level. The voice input / output unit 121 includes a speaker, a microphone, and the like, and amplifies a ringtone and a received voice or collects a voice.

  In addition, the ring tone generator 123 generates a ring tone in response to a call from the base station. The switching unit 119 switches the amplifying unit 120 connected to the voice processing unit 118 to the ringing tone generating unit 123 only when an incoming call is received, so that the ringing tone generated in the ringing tone generating unit 123 is transmitted via the amplifying unit 120. To the audio input / output unit 121.

The call control memory unit 124 stores a program related to incoming / outgoing call control of communication.
The telephone number input unit 122 includes, for example, a number key from 0 to 9 and other keys. By pressing these number keys and the like, a telephone number of a call destination is input.

When the voltage applied to each functional unit such as the control unit 112 by the power supply unit 111 falls below a predetermined value, the voltage detection unit 116 detects the voltage drop and notifies the control unit 112 of the voltage drop. .
The predetermined voltage value at this time is a value set in advance as a minimum voltage necessary for stably operating the communication unit 114, and is, for example, about 3V.

Upon receiving the voltage drop notification from the voltage detection unit 116, the control unit 112 prohibits the operations of the radio unit 117, the voice processing unit 118, the switching unit 119, and the ring tone generation unit 123.
In particular, it is essential to stop the operation of the wireless unit 117 with high power consumption.
Further, the display unit 115 displays that the communication unit 114 has become unusable due to insufficient battery power.

That is, the operation of the communication unit 114 can be prohibited by the voltage detection unit 116 and the control unit 112, and that effect can be displayed on the display unit 115.
This display may be a text message, but as a more intuitive display, a x (X) mark may be attached to the telephone icon displayed at the top of the display surface of the display unit 115.
In addition, the function of the communication part 114 can be stopped more reliably by providing the power supply cutoff part 126 that can selectively cut off the power of the part related to the function of the communication part 114.

  As described above, according to the portable information device 110 of the present embodiment, the portable information device 110 of the present embodiment includes the high-quality piezoelectric vibrator 1 with improved operation reliability. Similarly, the information device itself can stably ensure continuity, improve the reliability of operation, and improve the quality.

(Radio watch)
Next, an embodiment of a radio timepiece according to the present invention will be described with reference to FIG.
The radio timepiece 130 of the present embodiment includes the piezoelectric vibrator 1 electrically connected to the filter unit 131, receives a standard radio wave including timepiece information, and automatically corrects it to an accurate time. This is a watch with a display function.
In Japan, there are transmitting stations (transmitting stations) that transmit standard radio waves in Fukushima Prefecture (40 kHz) and Saga Prefecture (60 kHz), each transmitting standard radio waves.
Long waves such as 40 kHz or 60 kHz have the property of propagating the surface of the earth and the property of propagating while reflecting the ionosphere and the surface of the earth, so the propagation range is wide, and the above two transmitting stations cover all of Japan. doing.

Hereinafter, the functional configuration of the radio timepiece 130 will be described in detail.
The antenna 132 receives a long standard wave of 40 kHz or 60 kHz.
The long-wave standard radio wave is obtained by subjecting time information called a time code to AM modulation on a 40 kHz or 60 kHz carrier wave.
The received long standard wave is amplified by the amplifier 133 and filtered and tuned by the filter unit 131 having the plurality of piezoelectric vibrators 1.
The piezoelectric vibrator 1 according to this embodiment includes crystal vibrator portions 138 and 139 having resonance frequencies of 40 kHz and 60 kHz that are the same as the carrier frequency.

Further, the filtered signal having a predetermined frequency is detected and demodulated by the detection and rectification circuit 134.
Subsequently, the time code is taken out via the waveform shaping circuit 135 and counted by the CPU 136.
The CPU 136 reads information such as the current year, accumulated date, day of the week, and time. The read information is reflected in the RTC 137, and accurate time information is displayed.
Since the carrier wave is 40 kHz or 60 kHz, the crystal vibrator units 138 and 139 are preferably vibrators having the tuning fork type structure described above.

In addition, although the above-mentioned description was shown in the example in Japan, the frequency of the long standard wave is different overseas.
For example, in Germany, a standard radio wave of 77.5 KHz is used.
Accordingly, when the radio timepiece 130 that can be used overseas is incorporated in a portable device, the piezoelectric vibrator 1 having a frequency different from that in Japan is required.

  As described above, according to the radio-controlled timepiece 130 of the present embodiment, since the high-quality piezoelectric vibrator 1 with improved operation reliability is provided, the radio-controlled timepiece itself is similarly stably secured. Therefore, it is possible to improve the operation reliability and to improve the quality.

Although the embodiments of the polishing method according to the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the scope of the present invention.
In the above-described embodiment, the polishing is finished when the resonance frequency of the AT cut wafer 156 corresponding to the desired thickness of the quartz wafer (tuning fork substrate) 155 is detected a predetermined number of times within a predetermined time. However, the present invention is not limited to this. Instead, the polishing may be terminated when the resonance frequency of the AT cut wafer 156 corresponding to the desired thickness of the quartz wafer (tuning fork substrate) 155 is detected once.

DESCRIPTION OF SYMBOLS 1 Piezoelectric vibrator 5 Piezoelectric vibrating piece 100 Oscillator 110 Portable information device 130 Radio clock 150 Polishing device 151 Upper surface plate 152 Lower surface plate 153 Sun gear 154 Internal gear 155 Crystal wafer (Tuning fork substrate)
156 AT cut wafer 157 carrier 158 probe

Claims (10)

A method for polishing a tuning fork wafer held on a carrier between an upper surface plate and a lower surface plate,
An AT cut wafer for thickness measurement is arranged on the carrier, the AT cut wafer is polished together with the tuning fork wafer, a resonance frequency of the AT cut wafer is detected, and the tuning fork wafer is detected based on the detection result. A polishing method characterized by controlling the thickness of the substrate.   After starting the polishing of the tuning fork wafer, the polishing is terminated when the resonance frequency of the AT cut wafer corresponding to a desired thickness of the tuning fork wafer is detected a predetermined number of times within a predetermined time. The polishing method according to claim 1.   The polishing method according to claim 1, wherein at least one AT-cut wafer is disposed at a center position of the carrier.   The AT cut wafer is arranged between the adjacent tuning fork wafers when the plurality of tuning fork wafers are held on the carrier. The polishing method described.   The polishing method according to claim 1, wherein the AT-cut wafer has a disk shape. A method of manufacturing a piezoelectric vibrating piece for forming an electrode on the surface of a piezoelectric plate on which an outer shape of the piezoelectric vibrating piece is formed using photolithography technology,
A method for manufacturing a piezoelectric vibrating piece, comprising the step of polishing the piezoelectric plate by the polishing method according to any one of claims 1 to 5.   A piezoelectric vibrator comprising the piezoelectric vibrating piece manufactured by the method for manufacturing a piezoelectric vibrating piece according to claim 6.   8. An oscillator, wherein the piezoelectric vibrator according to claim 7 is electrically connected to an integrated circuit as an oscillator.   8. An electronic apparatus, wherein the piezoelectric vibrator according to claim 7 is electrically connected to a time measuring unit.   A radio-controlled timepiece, wherein the piezoelectric vibrator according to claim 7 is electrically connected to a filter portion.

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