JP2009206759A - Piezoelectric vibration chip, piezoelectric vibrator, oscillator, electronic apparatus, radio wave clock, and method of manufacturing piezoelectric vibration chip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently reduce a CI value and achieve miniaturization of a piezoelectric vibration chip by shortening the whole length. <P>SOLUTION: The piezoelectric vibration chip 2 includes: a piezoelectric board 10 having a pair of vibration arm parts 11, 12 bent at least once so as to be arranged in parallel on a half-way position from a base end to a top and a base 13 for integrally fixing the base end sides of the pair of vibration arm parts; grooves 14 formed on both surfaces on the base end side of the pair of vibration arm parts respectively along a length direction; excitation electrodes 20, 21 formed on the outer surfaces of the pair of the vibration arm parts respectively to vibrate the pair of vibration arm parts when a driving voltage is applied; and a pair of mount electrodes 22, 23 formed on the outer surface of the base and electrically connected to the pair of excitation electrodes, respectively. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a piezoelectric vibrating piece made of a piezoelectric material such as quartz or lithium tantalate, a piezoelectric vibrator having the piezoelectric vibrating piece, an oscillator having the piezoelectric vibrator, an electronic device, a radio timepiece, and a method of manufacturing the piezoelectric vibrating piece. Is.

  In recent years, a piezoelectric vibrator using a crystal or the like is used as a time source, a timing source of a control signal, a reference signal source or the like in a mobile phone or a portable information terminal device. Various types of piezoelectric vibrators of this type are provided. As one of them, a cylinder package type piezoelectric vibrator in which a piezoelectric vibrating piece is sealed in a cylindrical case is known.

As shown in FIG. 30, the piezoelectric vibrator 200 includes a tuning fork type piezoelectric vibrating piece 201, a bottomed cylindrical case 202 that houses the piezoelectric vibrating piece 201, and the piezoelectric vibrating piece 201 in the case 202. And an airtight terminal 203 that is hermetically sealed.
The piezoelectric vibrating piece 201 is a tuning fork type vibrating piece formed of various piezoelectric materials, and is integrally formed with a pair of vibrating arm portions 210 arranged in parallel and a base end side of the pair of vibrating arm portions 210. The piezoelectric plate 212 includes a fixed base 211 and an electrode (not shown) formed on the outer surface of the piezoelectric plate 212.
The electrodes are formed on the outer surfaces of the pair of vibrating arm portions 210, and are formed on the outer surface of the excitation electrode that vibrates these vibrating arm portions 210 and the base 211, and is electrically connected to the excitation electrodes via the extraction electrodes. And a mount electrode connected to each other.

The hermetic terminal 203 includes an annular stem 215 made of a metal material, two lead terminals 216 arranged so as to penetrate the stem 215, and the lead terminal 216 and the stem 215 in an insulated state. It is composed of a filler 217 that fixes and seals the inside of the case 202.
The two lead terminals 216 protrude into the case 202 to support the piezoelectric plate 212 and are connected to the mount electrode as inner leads 216a, and the portions protruding out of the case 202 are outer leads 216b. . The outer lead 216b functions as an external connection terminal.
The case 202 is press-fitted into the outer periphery of the stem 215 and is fixedly fitted. Since the press-fitting of the case 202 is performed in a vacuum atmosphere, the space surrounding the piezoelectric vibrating piece 201 in the case 202 is hermetically sealed in a vacuum state.

  In the piezoelectric vibrator 200 configured as described above, when a driving voltage is applied to the outer leads 216b of the two lead terminals 216, current flows from the inner lead 216a to the piezoelectric vibrating piece 201 via the mount electrode. Thereby, the piezoelectric vibrating piece 201 oscillates at a predetermined frequency.

By the way, in recent years, as typified by mobile phones and the like, various electronic devices incorporating a piezoelectric vibrator have been miniaturized.
In particular, the package type (glass package, ceramic package, etc.) surface-mount type piezoelectric vibrator in which the piezoelectric vibrating piece is housed between the base substrate and the lid substrate, and the mounting area is larger than this type of piezoelectric vibrator. In a mold-type surface-mount piezoelectric vibrator (a cylinder package-type piezoelectric vibrator described above molded with a resin), it is effective to shorten the overall length in order to achieve miniaturization. This is because by shortening the overall length, the mounting area can be reduced, and it can be relatively easily reduced in size.
Therefore, there is also a demand for tuning fork-type piezoelectric vibrating reeds to be miniaturized by shortening the overall length.

By the way, in order to shorten the overall length of the tuning fork type piezoelectric vibrating piece, it is effective to shorten the length of the vibrating arm portion or the length of the base portion. However, the frequency F of the tuning-fork type piezoelectric vibrating piece is proportional to W / L ² where L is the length of the vibrating arm and W is the width of the vibrating arm. Therefore, when the length of the vibrating arm portion is shortened, in order to maintain the same frequency F, it is necessary to make the width of the vibrating arm portion smaller than the length of the vibrating arm portion.
However, when the width of the vibrating arm portion is reduced, there is a problem that the CI value (Crystal Impedance) increases. Therefore, it has been difficult to shorten the length of the vibrating arm portion while keeping the CI value low.

  On the other hand, if the overall length of the tuning-fork type piezoelectric vibrating piece is shortened by shortening the base, the vibration of the vibrating arm tends to become unstable and vibration leakage (vibration energy leakage) occurs through the base. As a result, the CI value may increase. In particular, due to the influence of vibration leakage, shortening the base length has not been considered a practically effective method.

Therefore, in order to shorten the overall length of the piezoelectric vibrating piece and reduce the size, it is necessary to devise a configuration on the vibrating arm portion side, not on the base portion side. As one of them, in a quartz crystal vibrator that vibrates in a torsional vibration mode, a vibrating arm is bent halfway, and the apparent length is not changed, and the substantial length is increased (patent) Reference 1). By applying this technique, it is possible to reduce the size of the piezoelectric vibrating piece.
JP-A-6-112761

  Certainly, by bending the vibrating arm partway through, it is possible to increase the weight of the vibrating arm part and lower the frequency while increasing the length of the substantial vibrating arm part. It is possible to reduce the size of the piezoelectric vibrating piece while keeping the CI value the same with the width of the arm portion. However, it has been difficult to further reduce the CI value to meet future needs for higher quality. That is, it is difficult not only to shorten the overall length, but also to reduce the size by shortening the overall length while sufficiently reducing the CI value.

  In addition, when the vibrating arm portion is bent, the rigidity is increased as compared with other portions. For this reason, when it is attempted to vibrate the vibrating arm portion in the bending vibration mode, the bent portion tends to become a vibration node. That is, the vibrating arm portion is in a state of being supported at two points, that is, the base end side fixed to the base portion and the bent portion (folded portion), and is not a primary vibration but a secondary vibration or the like. There was a risk of vibration in higher vibration modes. For this reason, there is a possibility that the vibration does not vibrate with a desired waveform and the reliability is lowered.

The present invention has been made in view of such circumstances, and its purpose is to reduce the overall length by reducing the CI value sufficiently and to reduce the size, and to reliably vibrate with the primary vibration. A highly reliable tuning-fork type piezoelectric vibrating piece that can be produced, and a method of manufacturing the piezoelectric vibrating piece for manufacturing the piezoelectric vibrating piece.
Furthermore, it is to provide a piezoelectric vibrator having the piezoelectric vibrating piece, an oscillator having the piezoelectric vibrator, an electronic device, and a radio timepiece.

The present invention provides the following means in order to solve the above problems.
The piezoelectric vibrating piece according to the present invention integrally fixes a pair of vibrating arm portions bent at least once so as to be arranged in parallel on the way from the proximal end to the distal end, and a proximal end side of the pair of vibrating arm portions. A piezoelectric plate having a base portion, grooves formed along the length direction on both surfaces of the pair of vibrating arm portions on the proximal end side, and formed on the outer surfaces of the pair of vibrating arm portions, respectively. An excitation electrode that vibrates a pair of vibrating arms when a drive voltage is applied, and a pair of mount electrodes formed on the outer surface of the base and electrically connected to the pair of excitation electrodes, respectively And.

  The method for manufacturing a piezoelectric vibrating piece according to the present invention is a method for manufacturing a plurality of piezoelectric vibrating pieces at a time using a wafer made of a piezoelectric material, wherein the wafer is etched by a photolithography technique, and the wafer is etched. A pair of vibrating arms bent at least once so as to be arranged in parallel on the way from the proximal end to the distal end, and a base that integrally fixes the proximal ends of the pair of vibrating arms. An outer shape forming step of forming a plurality of outer shapes, a groove portion forming step of forming groove portions along the length direction on both surfaces of the base end side of the pair of vibrating arm portions, and outer surfaces of the plurality of piezoelectric plates An electrode film is patterned on the surface, and an excitation electrode that vibrates the pair of vibrating arm portions when a driving voltage is applied is formed on the outer surface of the pair of vibrating arm portions. Electrically Characterized in that it comprises an electrode forming step of forming a connected pair of mount electrodes on an outer surface of said base, a cutting step of small pieces separately a plurality of the piezoelectric plate from the wafer, the.

In the piezoelectric vibrating piece and the method of manufacturing the piezoelectric vibrating piece according to the present invention, first, an outer shape forming step of forming an outer shape of a plurality of piezoelectric plates on the wafer by etching a wafer made of a piezoelectric material such as quartz by a photolithographic technique. I do. At this time, the piezoelectric plate includes a pair of vibrating arm portions bent at least once so as to be arranged in parallel on the way from the proximal end to the distal end, and a base portion integrally fixing the proximal end sides of the pair of vibrating arm portions. The outer shape is formed so as to be configured.
Next, a groove forming process is performed in which grooves are respectively formed along the length direction on both surfaces of the pair of vibrating arms on the base end side. Thereby, it is possible to obtain a vibrating arm portion whose base end side has an H-shaped cross section.

Next, an electrode forming process is performed in which an electrode film is patterned on the outer surfaces of the plurality of piezoelectric plates to form a pair of excitation electrodes and a pair of mount electrodes. At this time, patterning is performed so that a pair of excitation electrodes are formed on the outer surfaces of the pair of vibrating arms, and a pair of mount electrodes are formed on the outer surface of the base.
Then, a cutting process is performed in which the plurality of piezoelectric plates are separated from the wafer into small pieces. Thereby, a plurality of tuning fork type piezoelectric vibrating reeds can be manufactured at one time from one wafer.

In particular, the pair of vibrating arms whose base end sides are fixed to the base are bent at least once along the way to the tip, so even if the apparent length from the base end to the bent portion is shortened , The substantial length can be lengthened. Accordingly, the entire length of the piezoelectric vibrating piece can be shortened while maintaining the frequency, and further miniaturization can be achieved. Further, the frequency can be further reduced by increasing the number of times the vibrating arm portion is bent. In addition, since it is not necessary to shorten the length of the base, it is possible to maintain a state in which vibration leakage is sufficiently reduced.
Furthermore, since the groove is formed on the base end side of the pair of vibrating arms, the electric field efficiency between the pair of excitation electrodes can be increased when a driving voltage is applied. Therefore, vibration loss can be suppressed and vibration characteristics can be improved. Accordingly, the CI value can be sufficiently reduced while maintaining the width of the vibrating arm portion. In this way, the CI value can be made sufficiently low and the overall length can be shortened to reduce the size. In addition, the length of the base that can sufficiently reduce vibration leakage can be secured.

  In the piezoelectric vibrating piece according to the present invention, in the piezoelectric vibrating piece of the present invention, the groove portion is further formed on both surfaces of the bent vibrating arm portion on the bent portion side. Features.

  The method for manufacturing a piezoelectric vibrating piece according to the present invention is the method for manufacturing a piezoelectric vibrating piece according to the present invention, wherein both sides of the vibrating arm portion on the bent side in the groove portion forming step are on the bent portion side. Further, the groove is further formed.

  In the piezoelectric vibrating piece and the method of manufacturing the piezoelectric vibrating piece according to the present invention, a groove is formed on the bent side of the bent vibrating arm in addition to the base end side of the vibrating arm. Therefore, the electric field efficiency between the pair of excitation electrodes can be increased on the bent portion side. Therefore, it is difficult for the bent portion to become a node during vibration. As a result, the pair of vibrating arms does not appear to be supported at two points in appearance, so that the pair of vibrating arms does not enter a high-order vibration mode such as a secondary vibration but performs a primary vibration. Therefore, even if the vibrating arm portion is bent halfway, it can be vibrated in an ideal bending vibration mode, and the reliability can be improved.

  The piezoelectric vibrator according to the present invention includes the above-described piezoelectric vibrating piece according to the present invention.

  Since the piezoelectric vibrator according to the present invention includes the above-described piezoelectric vibrating piece, the overall length can be shortened compared to the conventional size, and the size can be reduced, and the need for downsizing can be met. Further, since the piezoelectric resonator element has a sufficiently low CI value and sufficiently reduced vibration leakage, a high-quality piezoelectric vibrator with improved reliability can be obtained.

  Further, the piezoelectric vibrator according to the present invention is the above-described piezoelectric vibrator according to the present invention, wherein the base substrate with the piezoelectric vibrating piece mounted on the upper surface and the mounted piezoelectric vibrating piece accommodated in the cavity is provided. A lid substrate bonded to the substrate, and a pair of external electrodes formed on the lower surface of the base substrate and electrically connected to the pair of mount electrodes of the mounted piezoelectric vibrating piece. It is characterized by that.

In the piezoelectric vibrator according to the present invention, the piezoelectric vibrating piece is accommodated in a cavity formed between the base substrate and the lid substrate joined to each other. At this time, the piezoelectric vibrating piece is mounted on the upper surface of the base substrate while being electrically connected to the pair of external electrodes. Thereby, since a voltage can be applied to a pair of mount electrodes by applying a drive voltage to a pair of external electrodes, a pair of vibration arm parts can be vibrated.
In particular, since the piezoelectric resonator element can be a surface-mount package type piezoelectric vibrator in which the piezoelectric resonator element is sealed in a cavity, the piezoelectric resonator element can be vibrated without being affected by dust and the like. Further, it can be vibrated with high accuracy. In addition, since it is a surface mount type, it can be mounted easily and has excellent stability after mounting.

  The piezoelectric vibrator according to the present invention is the above-described piezoelectric vibrator according to the present invention, a case that houses the piezoelectric vibrating piece, a stem that is formed in an annular shape and press-fitted into the case, and the stem With one end side being electrically connected to the pair of mount electrodes, and the other end side being outer leads electrically connected to the outside. And two lead terminals, a filler for fixing the lead terminals and the stem, and an airtight terminal for sealing the inside of the case.

In the piezoelectric vibrator according to the present invention, the piezoelectric vibrating piece is housed in the case sealed by the airtight terminal. At this time, the piezoelectric vibrating piece is mounted by the lead terminals in a state where the pair of mount electrodes are electrically connected to the inner leads of the two lead terminals, respectively. Thus, by applying a driving voltage to the outer leads of the two lead terminals, a voltage can be applied to the fixed mount electrode, and thus the pair of vibrating arms can be vibrated.
In particular, since the piezoelectric resonator element can be a cylinder package type piezoelectric vibrator in which the piezoelectric resonator element is sealed in a case, the piezoelectric resonator element can be vibrated without being affected by dust, etc. Can be vibrated.

The oscillator according to the present invention is characterized in that the piezoelectric vibrator according to the present invention is electrically connected to an integrated circuit as an oscillator.
In addition, an electronic device according to the present invention is characterized in that the piezoelectric vibrator of the present invention is electrically connected to a timer unit.
The radio timepiece according to the present invention is characterized in that the piezoelectric vibrator of the present invention is electrically connected to a filter portion.

  Since the oscillator, electronic device, and radio timepiece according to the present invention include the piezoelectric vibrator described above, it is possible to reduce the size in the same manner, and to improve the reliability and improve the quality. .

According to the piezoelectric vibrating piece and the method of manufacturing the piezoelectric vibrating piece according to the present invention, the CI value can be sufficiently lowered, the entire length can be shortened and the size can be reduced, and the primary vibration can be reliably vibrated. A piezoelectric vibrating piece that can be obtained can be obtained.
In addition, according to the piezoelectric vibrator, oscillator, electronic device, and radio timepiece according to the present invention, since the above-described piezoelectric vibrating piece is provided, the size can be reduced in the same manner, and the reliability can be improved and increased. Quality can be improved.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS.
In the present embodiment, a surface mount type glass package type piezoelectric vibrator will be described as an example.
As shown in FIGS. 1 to 4, the piezoelectric vibrator 1 of the present embodiment is formed in a box shape in which a base substrate 3 and a lid substrate 4 are laminated in two layers. This is a piezoelectric vibrator in which the resonator element 2 is housed.
In FIG. 4, illustrations of excitation electrodes 20 and 21, extraction electrodes 25 and 26, and mount electrodes 22 and 23, which will be described later, are omitted for easy understanding of the drawing.

As shown in FIGS. 5 to 7, the piezoelectric vibrating piece 2 includes a tuning fork-type piezoelectric plate 10 made of a piezoelectric material such as quartz, lithium tantalate, or lithium niobate.
The piezoelectric plate 10 is integrally formed with a pair of vibrating arm portions 11 and 12 bent once so as to be arranged in parallel on the way from the proximal end to the distal end, and the proximal end sides of the pair of vibrating arm portions 11 and 12. And a base 13 to be fixed.

The pair of vibrating arm portions 11 and 12 are both formed with an equal thickness and width from the base end to the tip, and are formed in a state of being bent from the inside to the outside on the way to the tip. At this time, it is bent approximately 180 degrees so as to be U-shaped. As a result, the pair of vibrating arm portions 11 and 12 are in a state in which the bent front and rear portions are arranged in parallel. The bent portions are hereinafter referred to as bent portions 11a and 12a.
Moreover, the groove part 14 is each formed along the length direction in both surfaces of the base end side of a pair of vibrating arm part 11 and 12 of this embodiment. The pair of vibrating arm portions 11 and 12 has an H-shaped cross section as shown in FIG.

A pair of excitation electrodes 20 and 21 and a pair of mount electrodes 22 and 23 are formed on the outer surface of the piezoelectric plate 10 thus formed by patterning the electrode film, as shown in FIGS. Yes.
The pair of excitation electrodes 20 and 21 are electrodes that vibrate the pair of vibrating arm portions 11 and 12 when a driving voltage is applied, and are electrically connected to the outer surfaces of the pair of vibrating arm portions 11 and 12, respectively. It is formed in a separated state. Specifically, one excitation electrode 20 is mainly formed on the groove portion 14 of one vibration arm portion 11 and on both side surfaces of the other vibration arm portion 12, and the other excitation electrode 21 is formed on one of the vibration arm portions 12. It is mainly formed on both side surfaces of the vibrating arm portion 11 and on the groove portion 14 of the other vibrating arm portion 12.

The pair of mount electrodes 22 and 23 are formed on the outer surface of the base portion 13 and are electrically connected to the pair of excitation electrodes 20 and 21 via the extraction electrodes 25 and 26, respectively. A drive voltage is applied to the pair of excitation electrodes 20 and 21 via the mount electrodes 22 and 23.
The excitation electrodes 20 and 21, the extraction electrodes 25 and 26, and the mount electrodes 22 and 23 described above are, for example, a laminated film of chromium (Cr) and gold (Au), and a chromium film having good adhesion to crystal is used. After the film is formed as a base, a gold thin film is applied to the surface. However, the present invention is not limited to this. For example, a gold thin film may be further laminated on the surface of a laminated film of chromium and nichrome (NiCr), or a simple film of chromium, nickel, aluminum (Al), titanium (Ti), or the like. A layer film may be used.

  A weight metal film (coarse adjustment film 27a and a rough adjustment film 27a) for adjusting (frequency adjustment) to vibrate its own vibration state within a predetermined frequency range is provided at the ends of the bent vibration arm portions 11 and 12. 27 made of a fine-tuning film 27b is formed. By adjusting the frequency using the weight metal film 27, the frequency of the pair of vibrating arm portions 11 and 12 can be kept within the range of the nominal frequency of the device.

  The piezoelectric vibrating reed 2 configured as described above is mounted on the upper surface of the base substrate 3 by bump bonding using bumps B such as gold as shown in FIGS. More specifically, a pair of mount electrodes 22 and 23 are bump-bonded on two bumps B formed on routing electrodes 36 and 37, which will be described later, patterned on the upper surface of the base substrate 3, respectively. ing. As a result, the piezoelectric vibrating reed 2 is supported in a state where it floats from the upper surface of the base substrate 3, and the mount electrodes 22, 23 and the routing electrodes 36, 37 are electrically connected to each other.

  The lid substrate 4 is a transparent insulating substrate made of a glass material, for example, soda-lime glass, and is formed in a plate shape as shown in FIGS. A rectangular concave portion 4a in which the piezoelectric vibrating piece 2 is accommodated is formed on the bonding surface side to which the base substrate 3 is bonded. The recess 4 a is a cavity recess that serves as a cavity C that accommodates the piezoelectric vibrating reed 2 when the substrates 3 and 4 are overlapped. The lid substrate 4 is anodically bonded to the base substrate 3 with the recess 4a facing the base substrate 3 side.

The base substrate 3 is a transparent insulating substrate made of a glass material, for example, soda lime glass, like the lid substrate 4, and has a size that can be superimposed on the lid substrate 4 as shown in FIGS. It is formed in a plate shape.
The base substrate 3 is formed with a pair of through holes 30 and 31 penetrating the base substrate 3. At this time, the pair of through holes 30 and 31 are formed so as to be accommodated in the cavity C. More specifically, one through hole 30 is positioned on the base 13 side of the mounted piezoelectric vibrating reed 2, and the other through hole 31 is positioned on the distal end side of the vibrating arm portions 11 and 12. .
In the present embodiment, the through holes 30 and 31 that pass straight through the base substrate 3 will be described as an example. However, the present invention is not limited to this. For example, the diameter gradually decreases toward the lower surface of the base substrate 3. You may form in a taper shape. In any case, it only needs to penetrate the base substrate 3.

In the pair of through holes 30 and 31, a pair of through electrodes 32 and 33 formed so as to fill the through holes 30 and 31 are formed. The through-electrodes 32 and 33 completely close the through-holes 30 and 31 to maintain the airtightness in the cavity C, and also have a role of conducting the external electrodes 38 and 39 described later and the lead-out electrodes 36 and 37. ing.
On the upper surface side of the base substrate 3 (the bonding surface side to which the lid substrate 4 is bonded), a bonding film 35 for anodic bonding and a pair of lead-out electrodes 36 and 37 are patterned by a conductive material (for example, aluminum). Has been. Of these, the bonding film 35 is formed along the periphery of the base substrate 3 so as to surround the periphery of the recess 4 a formed in the lid substrate 4.

The pair of lead-out electrodes 36 and 37 electrically connect one of the through electrodes 32 and 33 to the one mount electrode 22 of the piezoelectric vibrating piece 2 and the other through electrode. 33 is patterned so as to electrically connect 33 and the other mount electrode 23 of the piezoelectric vibrating piece 2.
More specifically, as shown in FIGS. 2 to 4, the one lead-out electrode 36 is formed right above the one through electrode 32 so as to be positioned directly below the base portion 13 of the piezoelectric vibrating piece 2. The other routing electrode 37 is routed from the position adjacent to the one routing electrode 36 to the distal end side of the vibrating arm portions 11 and 12 along the vibrating arm portions 11 and 12, and then the other through electrode 33. It is formed so that it may be located just above.
A bump B is formed on the pair of routing electrodes 36 and 37, and the piezoelectric vibrating piece 2 is mounted using the bump B. As a result, one mount electrode 22 of the piezoelectric vibrating reed 2 is electrically connected to one through electrode 32 through one lead-out electrode 36, and the other mount electrode 23 passes through the other lead-out electrode 37. The electrode 33 is electrically connected.

  Further, as shown in FIGS. 1, 3, and 4, external electrodes 38 and 39 that are electrically connected to the pair of through electrodes 32 and 33 are formed on the lower surface of the base substrate 3. . That is, one external electrode 38 is electrically connected to one mount electrode 22 of the piezoelectric vibrating piece 2 through one through electrode 32 and one routing electrode 36. The other external electrode 39 is electrically connected to the other mount electrode 23 of the piezoelectric vibrating piece 2 via the other through electrode 33 and the other routing electrode 37.

Next, a method for manufacturing the above-described piezoelectric vibrating piece 2 and piezoelectric vibrator 1 will be described below with reference to the flowcharts shown in FIGS.
First, using the wafer S made of a piezoelectric material, a piezoelectric vibrating piece manufacturing step (S10) for manufacturing a plurality of piezoelectric vibrating pieces 2 shown in FIGS. 5 to 7 at a time is performed.
In performing this process, first, polishing is completed, and a wafer S finished to a predetermined thickness with high accuracy is prepared (S11). Next, the wafer S is etched by a photolithographic technique, and an outer shape forming step for forming the outer shapes of the plurality of piezoelectric plates 10 on the wafer S is performed (S12). This step will be specifically described.

First, as shown in FIG. 10, an etching protection film 40 is formed on each surface of the wafer S (S12a). As the etching protection film 40, for example, chromium (Cr) is formed to a thickness of several μm. Next, a photoresist film (not shown) is patterned on the etching protection film 40 by a photolithography technique. At this time, patterning is performed so as to surround the periphery of the piezoelectric plate 10 constituted by the pair of vibrating arm portions 11 and 12 bent one way and the base portion 13. Then, etching is performed using the photoresist film as a mask, and the unmasked etching protection film 40 is selectively removed. Then, the photoresist film is removed after the etching process.
11 and 12, the etching protection film 40 can be patterned along the outer shape of the piezoelectric plate 10, that is, the outer shapes of the pair of vibrating arm portions 11 and 12 and the base portion 13 (see FIG. 11 and FIG. 12). S12b). At this time, patterning is performed by the number of the plurality of piezoelectric plates 10. 12 to 15 are cross-sectional views taken along the line C-C shown in FIG.

  Next, both surfaces of the wafer S are etched using the patterned etching protective film 40 as a mask (S12c). As a result, as shown in FIG. 13, the region not masked by the etching protection film 40 can be selectively removed to form the outer shape of the piezoelectric plate 10. At this point, the outer shape forming process ends.

  Then, the groove part formation process which forms the groove part 14 in a pair of vibration arm parts 11 and 12 is performed (S13). Specifically, a photoresist film (not shown) is formed on the etching protective film 40 in the same manner as in the outer shape formation described above. Then, the photoresist film is patterned by the photolithography technique so as to open the region of the groove 14. Then, etching is performed using the patterned photoresist film as a mask, and the etching protection film 40 is selectively removed. Thereafter, by removing the photoresist film, as shown in FIG. 14, the already patterned etching protection film 40 can be further patterned in a state where the region of the groove portion 14 is left open.

Next, the wafer S is etched using the re-patterned etching protective film 40 as a mask, and then the etching protective film 40 used as the mask is removed. Thereby, as shown in FIG. 15, the groove part 14 can be formed in both surfaces of the base end side of a pair of vibration arm parts 11 and 12, respectively.
The plurality of piezoelectric plates 10 are in a state of being connected to the wafer S via a connecting portion (not shown) until a subsequent cutting step is performed.

  Next, an electrode film is formed on the outer surfaces of the plurality of piezoelectric plates 10 and patterned to form excitation electrodes 20 and 21, extraction electrodes 25 and 26, and mount electrodes 22 and 23, respectively. (S14). At the same time, the weight metal film 27 is formed by the same method (S15).

Next, the resonance frequency is coarsely adjusted (S16). This is done by irradiating the coarse adjustment film 27a of the weight metal film 27 with laser light to evaporate a part thereof and changing the weight. The fine adjustment for adjusting the resonance frequency with higher accuracy will be performed later. This will be described later.
Finally, a connecting step that connects the wafer S and the piezoelectric plate 10 is cut, and a cutting process is performed in which the plurality of piezoelectric plates 10 are separated from the wafer S to be cut into pieces (S17). Thereby, a plurality of tuning fork type piezoelectric vibrating reeds 2 can be manufactured from one wafer S at a time. At this point, the manufacturing process of the piezoelectric vibrating piece 2 is completed.

Next, a first wafer manufacturing process is performed in which a lid substrate wafer 45 to be the lid substrate 4 later is manufactured up to the state immediately before anodic bonding (S20).
First, after polishing and cleaning soda-lime glass to a predetermined thickness, as shown in FIG. 16, a disk-shaped lid substrate wafer 45 is formed by removing the outermost work-affected layer by etching or the like ( S21). Next, a recess forming step for forming a plurality of recesses 4a for the cavity C in the matrix direction by etching or the like is performed on the bonding surface of the lid substrate wafer 45 (S22). At this point, the first wafer manufacturing process is completed.

Next, at the same time as the above process or at the timing before and after, a second wafer manufacturing process is performed in which the base substrate wafer 46 to be the base substrate 3 is manufactured up to the state immediately before anodic bonding (S30).
First, after polishing and washing soda-lime glass to a predetermined thickness, a disk-shaped base substrate wafer 46 is formed from which the outermost work-affected layer has been removed by etching or the like (S31). Next, as shown in FIG. 17, a through hole forming step (S 32) for forming a plurality of pairs of through holes 30 and 31 that penetrate the base substrate wafer 46 is performed. Note that a dotted line M shown in FIG. 17 illustrates a cutting line that is cut in a cutting process to be performed later.
At this time, when the wafers 45 and 46 are overlapped later, a plurality of pairs of through holes 30 and 31 are formed so as to be accommodated in the recess 4a formed in the lid substrate wafer 45. In addition, one through hole 30 is formed on the base 13 side of the piezoelectric vibrating reed 2 to be mounted later, and the other through hole 31 is formed on the tip side of the vibrating arm portions 11 and 12.

Subsequently, a through electrode forming step for filling the plurality of pairs of through holes 30 and 31 with a conductor (not shown) to form the pair of through electrodes 32 and 33 is performed (S33).
Subsequently, a conductive material is patterned on the upper surface of the base substrate wafer 46, and as shown in FIG. 18, a bonding film forming step (S34) for forming the bonding film 35 is performed, and the pair of through electrodes 32 and 33 are formed. A routing electrode forming step of forming a plurality of routing electrodes 36 and 37 electrically connected to each other is performed (S35). In addition, the dotted line M shown in FIG. 18 has shown the cutting line cut | disconnected by the cutting process performed later.
By performing this step, one through electrode 32 and one routing electrode 36 are electrically connected, and the other through electrode 33 and the other routing electrode 37 are electrically connected. At this point, the second wafer manufacturing process is completed.

  By the way, in FIG. 9, the order of steps for performing the routing electrode formation step (S35) is performed after the bonding film formation step (S34). On the contrary, the bonding film formation is performed after the routing electrode formation step (S35). Step (S34) may be performed, or both steps may be performed simultaneously. Regardless of the order of steps, the same effects can be obtained. Therefore, the process order may be changed as necessary.

  Next, a mounting step is performed in which the produced plurality of piezoelectric vibrating reeds 24 are bump-bonded to the upper surface of the base substrate wafer 46 via the routing electrodes 36 and 37, respectively (S40). First, bumps B such as gold are formed on the pair of lead-out electrodes 36 and 37, respectively. Then, after the base portion 13 of the piezoelectric vibrating piece 2 is placed on the bump B, the piezoelectric vibrating piece 2 is pressed against the bump B while the bump B is heated to a predetermined temperature. As a result, the piezoelectric vibrating reed 2 is mechanically supported by the bumps B, and the mount electrodes 22 and 23 and the routing electrodes 36 and 37 are electrically connected. Therefore, at this point, the pair of excitation electrodes 20 and 21 of the piezoelectric vibrating piece 2 are in conduction with the pair of through electrodes 32 and 33, respectively. In particular, since the piezoelectric vibrating reed 2 is bump-bonded, it is supported in a state where it floats from the upper surface of the base substrate wafer 46.

  After the mounting of the piezoelectric vibrating reed 2 is completed, an overlaying step of overlaying the lid substrate wafer 45 on the base substrate wafer 46 is performed (S50). Specifically, both wafers 45 and 46 are aligned at the correct positions while using a reference mark (not shown) as an index. As a result, the mounted piezoelectric vibrating reed 2 is housed in the cavity C surrounded by the recess 4 a formed in the lid substrate wafer 45 and both the wafers 45 and 46.

  After the superposition process, the superposed two wafers 45 and 46 are put in an anodic bonding apparatus (not shown), and a bonding process is performed in which a predetermined voltage is applied in a predetermined temperature atmosphere to perform anodic bonding (S60). Specifically, a predetermined voltage is applied between the bonding film 35 and the lid substrate wafer 45. As a result, an electrochemical reaction occurs at the interface between the bonding film 35 and the lid substrate wafer 45, and the two are firmly bonded and anodically bonded. Thereby, the piezoelectric vibrating piece 2 can be sealed in the cavity C, and a wafer body in which the base substrate wafer 46 and the lid substrate wafer 45 are bonded can be obtained.

  After the anodic bonding described above is completed, a conductive material is patterned on the lower surface of the base substrate wafer 46, and a pair of external electrodes 38 and 39 electrically connected to the pair of through electrodes 32 and 33, respectively. A plurality of external electrode forming steps are formed (S70). By this step, the piezoelectric vibrating reed 2 sealed in the cavity C can be operated using the external electrodes 38 and 39.

  Next, a fine adjustment step is performed in which the frequency of each piezoelectric vibrator 1 sealed in the cavity C is finely adjusted within a predetermined range within the wafer body (S80). More specifically, a voltage is applied to the external electrodes 38 and 39 to vibrate the piezoelectric vibrating piece 2. Then, laser light is irradiated from the outside through the lid substrate wafer 45 while measuring the frequency, and the fine adjustment film 27b of the weight metal film 27 is evaporated. Thereby, since the weight of the tip end side of the pair of vibrating arm portions 10 and 11 is changed, the frequency of the piezoelectric vibrating piece 2 can be finely adjusted so as to be within a predetermined range of the nominal frequency.

After the fine adjustment of the frequency is completed, a cutting process is performed in which the bonded wafer body is cut along the cutting line M shown in FIG. As a result, the surface mount type piezoelectric vibrator 1 shown in FIG. 1 once sealed with the piezoelectric vibrating reed 2 in the cavity C formed between the base substrate 3 and the lid substrate 4 which are anodically bonded to each other is once formed. Multiple products can be manufactured.
In addition, after performing the cutting process (S90) and dividing into individual piezoelectric vibrators 1, the order of processes in which the fine adjustment process (S80) is performed may be used. However, as described above, by performing the fine adjustment step (S80) first, fine adjustment can be performed in the state of the wafer body, so that the plurality of piezoelectric vibrators 1 can be finely adjusted more efficiently. Therefore, the throughput can be improved, which is more preferable.

  Thereafter, an internal electrical characteristic inspection is performed (S100). That is, the resonance frequency, resonance resistance value, drive level characteristic (excitation power dependence of resonance frequency and resonance resistance value), etc. of the piezoelectric vibrating piece 2 are measured and checked. In addition, the insulation resistance characteristics and the like are also checked. Finally, an appearance inspection of the piezoelectric vibrator 1 is performed to finally check dimensions, quality, and the like. This completes the manufacture of the piezoelectric vibrator 1.

  When the piezoelectric vibrator 1 configured as described above is operated, a predetermined drive voltage is applied between the pair of external electrodes 38 and 39. As a result, current can be passed through the excitation electrodes 20 and 21 via the mount electrodes 22 and 23 and the extraction electrodes 25 and 26, and the pair of vibrating arm portions 11 and 12 can be vibrated at a predetermined frequency. The vibrations of the pair of vibrating arm portions 11 and 12 can be used as a time source, a control signal timing source, a reference signal source, and the like.

  In particular, the piezoelectric vibrating reed 2 according to the present embodiment is bent one time in the middle of the pair of vibrating arm portions 11 and 12 toward the distal end, so that the apparent length from the base end to the bent portions 11a and 12a. Even if the length is shortened, the substantial length can be lengthened. Accordingly, the entire length of the piezoelectric vibrating piece 2 can be shortened while maintaining the frequency, and further miniaturization can be achieved. In addition, since it is not necessary to shorten the length of the base portion 13, it is possible to maintain a state in which vibration leakage is sufficiently reduced. In addition, since a sufficient area can be secured for the mount, the mountability of the piezoelectric vibrating piece 2 is not affected.

  Further, since the groove portion 14 is formed on the base end side of the pair of vibrating arm portions 11 and 12, the pair of excitation electrodes 20 and 21 are in a positional relationship in which they partially face each other with the piezoelectric vibrating piece 2 interposed therebetween. . Therefore, the electric field efficiency between the pair of excitation electrodes 20 and 21 can be increased. Therefore, vibration loss can be suppressed and vibration characteristics can be improved. Therefore, the CI value can be sufficiently reduced while maintaining the width of the vibrating arm portions 11 and 12.

As described above, according to the piezoelectric vibrating piece 2 of the present embodiment, the CI value can be sufficiently lowered, and the overall length can be shortened to reduce the size. Moreover, the length of the base 13 that can sufficiently reduce vibration leakage can be secured.
Further, according to the piezoelectric vibrator 1 of the present embodiment, since the piezoelectric vibrating reed 2 described above is provided, the overall length can be shortened compared to the conventional case, and the size can be reduced. Can do. In addition, since the piezoelectric resonator element 2 has a sufficiently low CI value and sufficiently reduced vibration leakage, the high-quality piezoelectric vibrator 1 with improved reliability can be obtained.
Furthermore, since this piezoelectric vibrator 1 is a surface-mounted glass package type in which the piezoelectric vibrating piece 2 is sealed in the cavity C, the piezoelectric vibrating piece 2 can be vibrated without being affected by dust or the like. High quality can be achieved. In addition, since it is a surface mount type, it can be mounted easily and has excellent stability after mounting.

In the above-described embodiment, the surface-implemented glass package type piezoelectric vibrator is described as an example of the piezoelectric vibrator, but is not limited to this type of piezoelectric vibrator. For example, a so-called ceramic package type piezoelectric vibrator in which a mount electrode is formed on an insulating substrate such as ceramic, a mount electrode of a piezoelectric vibrating piece is connected to the mount electrode, and then hermetically sealed with a lid such as glass or metal may be used. Absent.
Further, instead of the surface mount type, for example, a cylinder package type piezoelectric vibrator as shown in FIG. 19 may be used. Next, the cylinder package type piezoelectric vibrator will be briefly described.

  19 and 20, the piezoelectric vibrator 50 includes a piezoelectric vibrating piece 2, a case 51 that houses the piezoelectric vibrating piece 2, and an airtight terminal that seals the piezoelectric vibrating piece 2 in the case 51. 52.

The piezoelectric vibrating reed 2 is mounted on the inner lead 61 a of the lead terminal 61 constituting the airtight terminal 52 while being housed in the case 51.
The case 51 is formed in a bottomed cylindrical shape, and is press-fitted into an outer periphery of a stem 60 (to be described later) of the airtight terminal 52, and is fitted and fixed. The case 51 is press-fitted in a vacuum, and the space surrounding the piezoelectric vibrating piece 2 in the case 51 is kept in a vacuum.

  The airtight terminal 52 seals the inside of the case 51, and is disposed in a state where the stem 60 is press-fitted and fixed in the case 51, and penetrates the stem 60. One end side of the stem 60 is sandwiched between the piezoelectric vibrations. Two lead terminals 61, which are inner leads 61a electrically connected to the pair of mount electrodes 22, 23 of the piece 2, and outer leads 61b whose other end is electrically connected to the outside, the leads A filler 62 for fixing the terminal 61 and the stem 60 is provided.

  The stem 60 is formed in a ring shape from a metal material (for example, low carbon steel (Fe), iron nickel alloy (Fe—Ni), iron nickel cobalt alloy (Fe—Ni—Co)). The material of the filler 62 is, for example, borosilicate glass. Note that the outer periphery of the stem 60 is coated with a plating (metal film) of the same material as the lead terminal 61.

  The lead terminal 61 is made of, for example, a conductive material that is the same material as the stem 60, and a portion protruding into the case 51 becomes an inner lead 61 a and a portion protruding outside the case 51 is an outer portion. Lead 61b is formed. The piezoelectric vibrating reed 2 is mechanically mounted by conductive bumps B such as gold while being placed at the tip of the inner lead 61a. That is, the inner lead 61a and the mount electrodes 22 and 23 are mechanically joined via the bumps B and are electrically connected at the same time. As a result, the piezoelectric vibrating piece 2 is mounted on the two lead terminals 61.

  As a material for plating the stem 60 and the lead terminal 61 constituting the piezoelectric vibrator 50 of the present embodiment, heat-resistant solder plating, tin-copper alloy, gold-tin alloy, or the like is used. Further, the inside of the case 51 can be hermetically sealed in a vacuum state by interposing plating on the outer periphery of the stem 60 and cold-welding the case 51 in a vacuum.

Next, a method for manufacturing the cylinder package type piezoelectric vibrator 50 will be described below with reference to the flowchart shown in FIG.
First, the piezoelectric vibrating reed 2 is manufactured by performing the piezoelectric vibrating reed manufacturing step (S10). Since this step has already been described in detail, the description thereof is omitted here.

Next, an airtight terminal production process for producing the airtight terminal 52 is performed (S110). Specifically, first, the stem 60 is manufactured by the stem manufacturing process (S111). That is, after a plate member having conductivity such as iron-nickel-cobalt alloy or iron-nickel alloy is lance processed, deep drawing is performed a plurality of times to form a bottomed cylindrical member. Then, an opening is formed on the bottom surface of the cylindrical member, and the stem 60 is manufactured by removing the outer shape and separating the cylindrical member from the plate member.
Next, a setting process for setting the lead terminal 61 and the filler 62 in the stem 60 is performed (S112). First, the prepared stem 60 is set in a dedicated jig (not shown), and then a filler 62 sintered in a ring shape in advance is set inside the stem 60 and lead terminals so as to penetrate the filler 62. 61 is set.

  After the stem 60, the lead terminal 61, and the filler 62 are combined by the above setting process, the jig is put in a heating furnace and the filler 62 is baked in a temperature atmosphere around 1000 ° C. (S113). Thereby, the space between the filler 62 and the lead terminal 61 and the space between the filler 62 and the stem 60 are completely sealed, and a structure that can withstand airtightness is obtained. And the airtight terminal 52 can be obtained by taking out from a jig | tool. At this point, the hermetic terminal manufacturing process ends.

Next, a plating process is performed in which a metal film of the same material is coated on the outer surface of the lead terminal 61 and the outer periphery of the stem 60 by a wet plating method (S120). As a pretreatment for that purpose, the outer surface of the lead terminal 61 and the outer periphery of the stem 60 are washed, degreased with an alkaline solution, and then washed with a solution of hydrochloric acid and sulfuric acid. After this pretreatment is completed, a base metal film is formed on the outer surface of the lead terminal 61 and the outer peripheral surface of the stem 60. For example, Cu plating or Ni plating is coated with a film thickness of approximately 2 μm to 5 μm. Subsequently, a finish metal film is formed on the base metal film. For example, in addition to a single material such as tin or silver, heat-resistant plating, tin copper alloy, tin bis film alloy, tin antimony alloy or the like is coated with a film thickness of approximately 8 μm to 15 μm.
In this way, the inner lead 61a and the piezoelectric vibrating piece 2 can be connected by coating the metal film including the base metal film and the finish metal film. In addition to the connection of the piezoelectric vibrating reed 2, the metal film coated on the outer periphery of the stem 60 has a characteristic of being soft and elastically deformed, so that the cold pressure welding between the stem 60 and the case 51 is enabled. And airtight joining can be performed.

  Subsequently, in order to stabilize the metal film, annealing is performed in a vacuum atmosphere furnace (S130). For example, heating is performed at a temperature of 170 ° C. for 1 hour. Thus, whisker generation can be suppressed by adjusting the composition of the intermetallic compound formed at the interface between the material of the base metal film and the material of the finished metal film. When this annealing is completed, a mounting process for mounting the piezoelectric vibrating piece 2 can be performed. In addition, although the case where it performed by the wet-plating method was taken as an example when coating a metal film, it is not restricted to this case, For example, you may carry out by a vapor deposition method, a chemical vapor phase method, etc.

In the present embodiment, after the annealing is completed, a conductive bump B such as gold is formed on the tip of the inner lead 61a for the next mounting process (S140). Then, the mount electrodes 22 and 23 formed on the outer surface of the base 13 are overlaid on the portion where the bump B is formed. Then, while heating the bump B, the inner lead 61a and the piezoelectric vibrating piece 2 are overlapped with each other through the bump B with a predetermined pressure. Thereby, the piezoelectric vibrating piece 2 can be mounted on the inner lead 61a (S150). That is, the piezoelectric vibrating reed 2 is mechanically supported by the lead terminal 61 in a state where the pair of mount electrodes 22 and 23 and the inner lead 61a are electrically connected.
In addition, although it mounted by performing heating and pressurization at the time of bump B connection, bump B connection may be performed using an ultrasonic wave.

  Next, baking is performed at a predetermined temperature in order to eliminate distortion due to the mount (S160). Subsequently, before fixing the case 51, the frequency adjustment (fine adjustment) of the piezoelectric vibrating piece 2 is performed (S170). This frequency adjustment will be described in detail. A voltage is applied between the outer leads 71b in a state where the whole is put in a vacuum chamber, and the piezoelectric vibrating piece 2 is vibrated. Then, the frequency is adjusted by evaporating the fine adjustment film of the weight metal film with a laser while measuring the frequency. By performing this frequency adjustment, the frequency of the piezoelectric vibrating piece 2 can be adjusted within a predetermined frequency range.

  Note that the frequency adjustment was performed by evaporating the weight metal film by laser irradiation during the fine adjustment and the coarse adjustment performed previously, but argon ions may be used instead of the laser. In this case, sputtering is performed by irradiation with argon ions, and the frequency is adjusted by removing the weight metal film.

Next, a sealing step is performed in which the case 51 is press-fitted into the stem 60 so as to accommodate the mounted piezoelectric vibrating reed 2 therein, and the piezoelectric vibrating reed 2 is hermetically sealed (S180). More specifically, the case 51 is press-fitted into the outer periphery of the stem 60 of the airtight terminal 52 while applying a predetermined load in a vacuum. Then, since the metal film formed on the outer periphery of the stem 60 is elastically deformed, it can be hermetically sealed by cold pressure welding. Thereby, the piezoelectric vibrating piece 2 can be sealed and vacuum-sealed in the case 51.
Before performing this step, it is preferable to sufficiently heat the piezoelectric vibrating piece 2, the case 51, and the airtight terminal 52 to desorb surface adsorbed moisture and the like.

  Then, after the case 51 is fixed, screening is performed (S190). This screening is performed in order to stabilize the frequency and the resonance resistance value and to suppress the occurrence of metal whisker due to compressive stress in the fitting portion into which the case 51 is press-fitted. After the screening is completed, an internal electrical characteristic inspection is performed (S200). That is, the resonance frequency, resonance resistance value, drive level characteristic (excitation power dependence of resonance frequency and resonance resistance value), etc. of the piezoelectric vibrating piece 2 are measured and checked. In addition, the insulation resistance characteristics and the like are also checked. Finally, an appearance inspection of the piezoelectric vibrator 50 is performed to finally check dimensions, quality, and the like. As a result, a plurality of piezoelectric vibrators 50 shown in FIGS. 19 and 20 can be manufactured at a time.

  Even the piezoelectric vibrator 50 configured as described above includes the piezoelectric vibrating reed 2 having a short overall length and a reduced size in a state where vibration leakage is sufficiently reduced. Can be achieved. In addition, since the piezoelectric vibrator 50 is a cylinder package type in which the piezoelectric vibrating piece 2 is sealed in the case 51, the piezoelectric vibrating piece 2 can be vibrated without being affected by dust or the like, and the quality can be improved. Can be planned.

In addition, the cylinder package type piezoelectric vibrator 50 may be further solidified by the mold resin portion 71 to form the surface mount vibrator 70.
As shown in FIGS. 22 and 23, the surface mount type vibrator 70 includes a piezoelectric vibrator 50, a mold resin portion 71 for fixing the piezoelectric vibrator 50 in a predetermined shape, and one end side electrically connected to the outer lead 61b. And an external connection terminal 72 having the other end exposed at the bottom surface of the mold resin portion 71 and electrically connected to the outside.
The external connection terminal 72 is formed in a U-shaped cross section with a metal material such as copper. Since the piezoelectric vibrator 50 is hardened with the mold resin portion 71 in this manner, it can be stably attached to a circuit board or the like, so that it is easier to use and the usability is improved. In particular, since the piezoelectric vibrator 50 has a short overall length and is miniaturized, the surface mount vibrator 70 itself can be miniaturized.

Next, an embodiment of an oscillator according to the present invention will be described with reference to FIG.
As shown in FIG. 24, 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. The integrated circuit 101 for the oscillator is mounted on the substrate 103, and the piezoelectric vibrating piece 2 of 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 2 in the piezoelectric vibrator 1 vibrates. This vibration is converted into an electric signal by the piezoelectric characteristics of the piezoelectric vibrating piece 2 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 the external device in addition to a single-function oscillator for a clock, etc. A function for controlling the time, providing a time, a calendar, and the like can be added.

  According to the oscillator 100 of the present embodiment, since the piezoelectric vibrator 1 described above is provided, the oscillator 100 itself can be reduced in size and the reliability of the product can be improved. In addition to this, it is possible to obtain a highly accurate frequency signal that is stable over a long period of time.

  Next, an embodiment of an electronic apparatus according to the 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. 25, 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 2 vibrates, and the vibration is converted into an electric signal by the piezoelectric characteristics of the crystal and 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.

  According to the portable information device 110 of this embodiment, since the piezoelectric vibrator 1 described above is provided, the portable information device 110 itself can be similarly reduced in size, and the reliability of the product can be improved. . In addition to this, it is possible to display highly accurate clock information that is stable over a long period of time.

Next, an embodiment of a radio timepiece 130 according to the present invention will be described with reference to FIG. As shown in FIG. 26, the radio timepiece 130 according to the present embodiment includes the piezoelectric vibrator 1 electrically connected to the filter unit 131, and receives a standard radio wave including timepiece information to accurately It is a clock with a function of automatically correcting and displaying the correct time.
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. is 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.

  According to the radio timepiece 130 of this embodiment, since the piezoelectric vibrator 1 described above is provided, the radio timepiece 130 itself can be similarly reduced in size, and the reliability of the product can be improved. In addition to this, it is possible to count time stably and with high accuracy over a long period of time.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the case where the pair of vibrating arm portions 11 and 12 are bent once in the middle toward the tip has been described as an example, but the number of times of bending may be two or more. In particular, as the number of times of bending is increased, the substantial length of the vibrating arm portions 11 and 12 can be increased, so that the frequency can be further reduced.

  Moreover, in the said embodiment, although the case where the pair of vibrating arm parts 11 and 12 was bent toward the outside from the inside was given as an example, as shown in FIG. 27, it was bent approximately 180 degrees from the outside to the inside. It doesn't matter. Even in this case, the same effects can be achieved. In FIG. 27, the excitation electrodes 20 and 21, the extraction electrodes 25 and 26, and the mount electrodes 22 and 23 are not shown.

  Moreover, in the said embodiment, although the groove part 14 was formed only in the base end side of a pair of vibration arm parts 11 and 12, as shown in FIG. 28, it bends among the vibration arm parts 11 and 12 by the side of bending. Grooves 14 may be further formed on both sides of the portions 11a and 12a. In this case, in the groove forming step, etching may be performed so that the groove 14 is simultaneously formed on the bent portions 11a and 12a on the base end side and the bent side.

  Thus, by forming the groove portion 14 on the bent portions 11a and 12a side as well, the pair of excitation electrodes 20 and 21 are partly opposed to each other on the bent portions 11a and 12a side. Can be raised. Therefore, the bent portions 11a and 12a are unlikely to become nodes during vibration. As a result, the pair of vibrating arm portions 11 and 12 do not appear to be supported at two points in appearance, so that the pair of vibrating arm portions 11 and 12 undergo primary vibration instead of high-order vibration mode such as secondary vibration. Therefore, even if the vibrating arm portions 11 and 12 are bent halfway, it can be vibrated in an ideal bending vibration mode, and the reliability can be improved.

  In addition, when forming the groove part 14 in the bending part 11a, 12a side, as shown in FIG. 29, even if it folds the vibrating arm parts 11 and 12 from the outer side to the inner side, the same effect can be obtained. Can do. Further, when the vibrating arm portions 11 and 12 are bent twice or more, the groove portion 14 may be formed each time on the bent side.

1 is an external perspective view showing an embodiment of a piezoelectric vibrator according to the present invention. FIG. 2 is an internal structural view 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 the figure which looked at the piezoelectric vibrating piece which comprises the piezoelectric vibrator shown in FIG. 1 from the upper surface. It is the figure which looked at the piezoelectric vibrating piece shown in FIG. 5 from the lower surface. It is a cross-sectional arrow BB figure shown in FIG. It is a flowchart at the time of manufacturing the piezoelectric vibrator shown in FIG. It is a continuation of the flowchart shown in FIG. It is a figure which shows 1 process at the time of manufacturing the piezoelectric vibrator shown in FIG. 1, Comprising: It is a figure which shows the state which formed the etching protective film on both surfaces of a wafer. It is a figure which shows the state which patterned the etching protective film in the external shape of the piezoelectric plate of a piezoelectric vibrating piece from the state shown in FIG. It is a cross-sectional arrow CC figure shown in FIG. It is a figure which shows the state which etched the wafer from the state shown in FIG. 12 by using an etching protective film as a mask. It is a figure which shows the state which further patterned the etching protective film from the state shown in FIG. It is a figure which shows the state which etched the wafer from the state shown in FIG. 14 by using the etching protection film patterned again as a mask. FIG. 2 is a diagram illustrating a step in manufacturing the piezoelectric vibrator illustrated in FIG. 1, and is a diagram illustrating a state in which a plurality of recesses are formed on a lid substrate wafer that is a base of a lid substrate. FIG. 2 is a diagram illustrating a step in manufacturing the piezoelectric vibrator illustrated in FIG. 1, and is a diagram illustrating a state in which a pair of through holes are formed in a base substrate wafer that is a base substrate. FIG. 18 is a diagram showing a state in which through electrodes are formed in a pair of through holes after the state shown in FIG. 17, and a bonding film and a routing electrode are patterned on the upper surface of the base substrate wafer. It is a figure which shows the modification of the piezoelectric vibrator which concerns on this invention, Comprising: It is a top view of a cylinder package type piezoelectric vibrator. FIG. 20 is a cross-sectional arrow view DD shown in FIG. 19. It is a flowchart at the time of manufacturing the piezoelectric vibrator shown in FIG. FIG. 20 is a diagram showing a modification of the piezoelectric vibrator according to the present invention, and is a cross-sectional view of a surface-mount type piezoelectric vibrator in which the periphery of the piezoelectric vibrator shown in FIG. 19 is molded with a mold resin portion. It is a perspective view which shows the attachment relationship of the piezoelectric vibrator shown in FIG. 22, and an external connection terminal. 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. It is a top view which shows the modification of the piezoelectric plate which comprises the piezoelectric vibrating piece which concerns on this invention. It is a top view which shows the modification of the piezoelectric plate which comprises the piezoelectric vibrating piece which concerns on this invention. It is a top view which shows the modification of the piezoelectric plate which comprises the piezoelectric vibrating piece which concerns on this invention. It is a perspective view which shows an example of the conventional piezoelectric vibrator.

Explanation of symbols

C: Cavity S: Wafer 1, 50 ... Piezoelectric vibrator 2 ... Piezoelectric vibrating piece 3 ... Base substrate 4 ... Lid substrate 10 ... Piezoelectric plate 11, 12 ... Vibrating arm portion 13 ... Base portion 14 ... Groove portion 20, 21 ... Excitation electrode 22 23 ... Mount electrode 38, 39 ... External electrode 51 ... Case 52 ... Airtight terminal 60 ... Stem 61 ... Lead terminal 61a ... Inner lead 61b ... Outer lead 62 ... Filling material 100 ... Oscillator 101 ... Oscillator integrated circuit 110 ... Portable information Equipment (electronic equipment)
113: Timekeeping unit of portable information device 130 ... Radio clock 131 ... Filter unit of radio clock

Claims (10)

A piezoelectric plate having a pair of vibrating arm portions bent at least once so as to be arranged in parallel on the way from the proximal end to the distal end, and a base portion integrally fixing the proximal end sides of the pair of vibrating arm portions;
Groove portions respectively formed along the length direction on both surfaces on the base end side of the pair of vibrating arm portions;
Excitation electrodes formed on the outer surfaces of the pair of vibrating arms, respectively, for vibrating the pair of vibrating arms when a driving voltage is applied;
A piezoelectric vibrating piece, comprising: a pair of mount electrodes formed on an outer surface of the base and electrically connected to the pair of excitation electrodes. The piezoelectric vibrating piece according to claim 1,
2. The piezoelectric vibrating piece according to claim 1, wherein the groove is further formed on both sides of the bent arm side on the bent side. A method of manufacturing a plurality of piezoelectric vibrating pieces at a time using a wafer made of a piezoelectric material,
The wafer is etched by photolithography, and a pair of vibrating arm portions bent at least once so as to be arranged in parallel on the wafer from the proximal end to the distal end, and the proximal end sides of the pair of vibrating arm portions An outer shape forming step of forming a plurality of outer shapes of the piezoelectric plate having a base portion fixed integrally;
A groove portion forming step for forming groove portions along the length direction on both surfaces of the pair of vibrating arm portions on the base end side; and
An electrode film is patterned on the outer surfaces of the plurality of piezoelectric plates to form excitation electrodes on the outer surfaces of the pair of vibrating arms when a driving voltage is applied to vibrate the pair of vibrating arms. Forming a pair of mount electrodes electrically connected to the pair of excitation electrodes on the outer surface of the base, and
And a cutting step of separating the plurality of piezoelectric plates from the wafer into small pieces. In the manufacturing method of the piezoelectric vibrating piece according to claim 3,
In the groove forming step, the groove is further formed on both sides of the bent arm portion on the bent portion side.   A piezoelectric vibrator comprising the piezoelectric vibrating piece according to claim 3. The piezoelectric vibrator according to claim 5, wherein
A base substrate for mounting the piezoelectric vibrating piece on the upper surface;
A lid substrate bonded to the base substrate in a state where the mounted piezoelectric vibrating piece is accommodated in a cavity;
A piezoelectric vibrator comprising: a pair of external electrodes formed on the lower surface of the base substrate and electrically connected to a pair of mount electrodes of the mounted piezoelectric vibrating piece. The piezoelectric vibrator according to claim 5, wherein
A case for housing the piezoelectric vibrating piece therein;
A stem formed in an annular shape and press-fitted and fixed in the case; an inner lead disposed through the stem and having one end side electrically connected to the pair of mount electrodes with the stem interposed therebetween; Two lead terminals whose outer ends are electrically connected to the outside, respectively, and a filler for fixing the lead terminals and the stem, and hermetically seal the inside of the case And a piezoelectric vibrator.   8. An oscillator, wherein the piezoelectric vibrator according to claim 5 is electrically connected to an integrated circuit as an oscillator.   8. An electronic apparatus, wherein the piezoelectric vibrator according to claim 5 is electrically connected to a timer unit.   A radio-controlled timepiece, wherein the piezoelectric vibrator according to claim 5 is electrically connected to a filter portion.

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