JP2010183537A - Piezoelectric vibration element manufacturing method and piezoelectric vibration element, piezoelectric vibrator, oscillator, electronic apparatus, and radio clock - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a piezoelectric vibration element which controls a variation in external accuracy and can obtain a stable vibration characteristic, and the piezoelectric vibration element, a piezoelectric vibrator, an oscillator, an electronic apparatus, and a radio clock. <P>SOLUTION: In a groove pattern forming process, a photoresist film 42 is formed so as to have an opening 42a in a groove forming area on a wafer mask 40 and to be larger than an external shape of the piezoelectric vibration element (mask 40 for wafer). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  2. Description of the Related Art In recent years, a piezoelectric vibrator using a crystal or the like is used as a time source, a timing source such as a control signal, a reference signal source, and the like in mobile phones and portable information terminal devices. Various piezoelectric vibrators of this type are known, and one of them is a surface mount (SMD) type piezoelectric vibrator. As this type of piezoelectric vibrator, for example, a base substrate and a lid substrate bonded to each other, a cavity formed between both substrates, and a piezoelectric vibrating piece housed in an airtightly sealed state in the cavity. I have.

The piezoelectric vibrating piece described above is formed on a pair of vibrating arm portions arranged in parallel, a base portion that integrally fixes the base end sides of the pair of vibrating arm portions, and an outer surface of the pair of vibrating arm portions, And a pair of excitation electrodes for vibrating the pair of vibrating arms.
The piezoelectric vibrating piece is generally manufactured by etching a wafer such as quartz. Specifically, for example, as shown in Patent Document 1, a wafer mask (first mask) that becomes an outer pattern of a piezoelectric vibrating piece is patterned into an outer shape of the piezoelectric vibrating piece, and the wafer is passed through the wafer mask. Therefore, the outer shape of the piezoelectric vibrating piece is formed.

By the way, this piezoelectric vibrating piece is desired to be further downsized as the equipment to be mounted is downsized. Several methods have been considered as a method for reducing the size, and one of them is a method of forming groove portions on both surfaces of the vibrating arm portion. According to this configuration, since the electric field efficiency between the pair of excitation electrodes can be increased, vibration loss can be suppressed and vibration characteristics can be improved. That is, it is said that the CI value (Crystal Impedance) of the piezoelectric vibrating piece can be further reduced after the piezoelectric vibrating piece is reduced in size.
In order to form the groove in the piezoelectric vibrating piece, first, a photoresist film to be a groove pattern is formed on the wafer mask described above. Next, the photoresist film is patterned so that the groove formation region is opened and the outer shape is the same as the outer shape of the wafer mask. After etching the wafer mask in the region exposed from the photoresist film (groove formation region), the groove formation region in the wafer is etched.

JP 2002-76806 A

  However, when the groove is formed in the piezoelectric vibrating piece, there is a problem that the overlay accuracy of the wafer mask that becomes the outer pattern and the photoresist film that becomes the groove pattern affects the accuracy of the outer shape of the actual piezoelectric vibrating piece. is there.

Here, a conventional method for manufacturing a piezoelectric vibrating piece will be described with reference to FIGS.
As shown in FIG. 32, when the photoresist film 242 is displaced with respect to the wafer mask 240, the outer peripheral portion of the wafer mask 240 is exposed by an amount corresponding to the shifted width.
Then, as shown in FIG. 33, when the wafer mask 240 in the groove formation region (opening 242a of the photoresist film 242) is etched using the photoresist film 242 as a mask, the outer periphery of the exposed wafer mask 240 is exposed. Both parts may be etched. As described above, in the configuration of Patent Document 1, since the outer shape of the photoresist film 242 is patterned to the same shape as the outer shape of the wafer mask 240, the overlay accuracy of the photoresist film 242 is likely to vary. There's a problem.
As a result, as shown in FIG. 34, the outer peripheral portion of the piezoelectric vibrating piece 204 is etched when the groove 218 is formed, and the piezoelectric vibrating piece 204 may not be formed in a desired outer shape as shown in FIG. As a result, variations occur in the piezoelectric vibrating reed 204 that is a product, resulting in variations in the frequency of the piezoelectric vibrating reed 204, leading to a decrease in vibration characteristics.

  Therefore, the present invention has been made in view of the above-described problems, and a piezoelectric vibrating piece manufacturing method, a piezoelectric vibrating piece, a piezoelectric vibrator, and the like, which can suppress variation in outer shape accuracy and obtain stable vibration characteristics. An oscillator, an electronic device, and a radio timepiece are provided.

In order to solve the above-described problems, the present invention provides the following means.
A method of manufacturing a piezoelectric vibrating piece according to the present invention includes a pair of vibrating arm portions arranged in parallel, a base portion that integrally fixes a base end side of the pair of vibrating arm portions, and a pair of vibrating arm portions on the pair of vibrating arm portions. A piezoelectric vibrating reed manufacturing method for manufacturing a piezoelectric vibrating reed from a wafer with a piezoelectric vibrating reed provided with a groove formed along the longitudinal direction of the vibrating arm on the wafer, wherein the piezoelectric vibrating reed is formed on the wafer. A first mask forming step of forming a first mask having an outer shape equivalent to the outer shape of the piezoelectric vibrating piece, and forming the outer shape of the piezoelectric vibrating piece and the groove, and on the first mask A second mask forming step of forming a second mask having an opening in the formation region of the groove, and a step of removing the first mask exposed from the opening using the second mask as a mask; And in the second mask forming step It is characterized by forming a second mask having a larger outer shape than the outer shape of the piezoelectric vibrating piece.

According to this configuration, since the second mask is formed larger than the piezoelectric vibrating piece, even if the overlay accuracy of the second mask varies, the groove formation region is formed by the second mask. The probability that the first mask excluding (opening) is completely covered up to the outer peripheral portion is increased. That is, it is possible to prevent the formation region (first mask) of the piezoelectric vibrating piece from being exposed from the second mask. Thereby, when removing the 1st mask exposed from the opening part, the outer peripheral part of a 1st mask is not removed. Therefore, when forming the groove portion, the groove portion can be formed without removing the outer peripheral portion of the piezoelectric vibrating piece. As a result, the piezoelectric vibrating piece can be formed in a desired outer shape. That is, the variation in the outer shape of the piezoelectric vibrating piece due to the variation in the overlay accuracy of the second mask can be suppressed.
Accordingly, it is possible to manufacture a piezoelectric vibrating piece having stable vibration characteristics while suppressing variations in the frequency of the piezoelectric vibrating piece.
In addition, according to the configuration of the present invention, since the outer shape of the second mask is only formed larger than the outer shape of the piezoelectric vibrating piece, it is stable while suppressing a decrease in manufacturing efficiency and an increase in manufacturing cost. A piezoelectric vibrating piece having the above vibration characteristics can be provided.

In the second mask forming step, an enlargement margin from the outer peripheral edge of the piezoelectric vibrating piece of the second mask is set in a range of 3 μm or more and 10 μm or less.
If the expansion margin of the second mask with respect to the outer shape of the piezoelectric vibrating piece is smaller than 3 μm, the outer peripheral portion of the first mask may be exposed from the second mask due to the limit of overlay accuracy of the second mask, which is not preferable. . On the other hand, if it is larger than 10 μm, the second mask becomes an obstacle in the step of forming the outer shape of the piezoelectric vibrating piece when the second mask protrudes greatly outside the first mask, and the piezoelectric vibration becomes an obstacle. Since there exists a possibility that it cannot pattern into the desired external shape of a piece, it is not preferable.
On the other hand, according to the configuration of the present invention, the expansion margin of the second mask with respect to the outer shape of the piezoelectric vibrating piece is set in the range of 3 μm or more and 10 μm or less, thereby affecting the process of forming the outer shape of the piezoelectric vibrating piece. The outer peripheral portion of the first mask can be reliably covered with the second mask within a range that does not affect the above.

Further, the second mask is formed larger than the piezoelectric vibrating piece along at least a short direction perpendicular to the longitudinal direction of the piezoelectric vibrating piece.
According to this configuration, the variation in vibration characteristics is effectively suppressed by forming the second mask larger than the outer shape of the piezoelectric vibration piece in the short direction of the piezoelectric vibration piece having a large influence on the vibration characteristics. can do.

In addition, after the second mask forming step, a step of forming an outer shape of the piezoelectric vibrating piece from the wafer using the first mask as a mask, and a step of forming the groove portion using the first mask as a mask. It is characterized by having.
According to this configuration, after the second mask forming step, the piezoelectric vibrating piece is formed in a desired outer shape, so that, for example, in the second mask forming step, the second mask forming material (for example, a photoresist film) is used. It can apply | coat collectively on a wafer by a spin coat method etc. Therefore, a uniform film can be rapidly formed over the entire surface of the wafer.

The step of forming the outer shape of the piezoelectric vibrating piece is performed by wet etching.
According to this configuration, even when the second mask covers the outer periphery of the first mask and is formed even on the wafer, the etchant enters between the second mask and the wafer, and the first mask Reach the outer periphery. Accordingly, the wafer can be reliably etched into the desired outer shape (outer shape of the piezoelectric vibrating piece) following the outer shape of the first mask.

The piezoelectric vibrating piece according to the present invention is manufactured by the method for manufacturing a piezoelectric vibrating piece according to the present invention.
According to this configuration, it is possible to provide a highly reliable piezoelectric vibrating piece that suppresses frequency variation and has stable vibration characteristics.

In addition, a piezoelectric vibrator according to the present invention includes the above-described piezoelectric vibrating piece according to the present invention.
According to this configuration, since the piezoelectric vibrating piece according to the present invention is provided, it is possible to provide a small-sized and high-performance piezoelectric vibrator with little frequency variation.

  An oscillator according to the present invention is characterized in that the piezoelectric vibrator of the present invention is electrically connected to an integrated circuit as an oscillator.

  In addition, an electronic apparatus according to the present invention is characterized in that the piezoelectric vibrator of the present invention is electrically connected to a timer unit.

  A 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 above-described piezoelectric vibrator, a highly reliable product can be provided in the same manner as the piezoelectric vibrator.

According to the method for manufacturing a piezoelectric vibrating piece and the piezoelectric vibrating piece using the manufacturing method according to the present invention, it is possible to manufacture a piezoelectric vibrating piece having stable vibration characteristics by suppressing variation in the frequency of the piezoelectric vibrating piece. it can.
Moreover, according to the piezoelectric vibrator according to the present invention, since the piezoelectric vibrating piece according to the present invention is provided, it is possible to provide a small and high-performance piezoelectric vibrator with little frequency variation.
Since the oscillator, electronic device, and radio timepiece according to the present invention include the above-described piezoelectric vibrator, a highly reliable product can be provided in the same manner as the piezoelectric vibrator.

1 is an external perspective view showing an embodiment of a piezoelectric vibrator according to 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. FIG. 2 is a top view of a piezoelectric vibrating piece constituting the piezoelectric vibrator shown in FIG. 1. FIG. 6 is a bottom view of the piezoelectric vibrating piece shown in FIG. 5. It is a cross-sectional arrow BB figure shown in FIG. It is a flowchart which shows the flow at the time of manufacturing the piezoelectric vibrating piece shown in FIG. FIG. 2 is a process diagram when manufacturing the piezoelectric vibrating piece shown in FIG. 1, and is a plan view of a wafer. FIG. 10 is a process diagram when the piezoelectric vibrating piece shown in FIG. 1 is manufactured, and is a cross-sectional view of the wafer along the line CC in FIG. 9. FIG. 10 is a process diagram when the piezoelectric vibrating piece shown in FIG. 1 is manufactured, and is a cross-sectional view of the wafer along the line CC in FIG. 9. FIG. 10 is a process diagram when the piezoelectric vibrating piece shown in FIG. 1 is manufactured, and is a cross-sectional view of the wafer along the line CC in FIG. 9. FIG. 10 is a process diagram when the piezoelectric vibrating piece shown in FIG. 1 is manufactured, and is a cross-sectional view of the wafer along the line CC in FIG. 9. FIG. 10 is a process diagram when the piezoelectric vibrating piece shown in FIG. 1 is manufactured, and is a cross-sectional view of the wafer along the line CC in FIG. 9. FIG. 10 is a process diagram when the piezoelectric vibrating piece shown in FIG. 1 is manufactured, and is a cross-sectional view of the wafer along the line CC in FIG. 9. FIG. 10 is a process diagram when the piezoelectric vibrating piece shown in FIG. 1 is manufactured, and is a cross-sectional view of the wafer along the line CC in FIG. 9. FIG. 10 is a process diagram when the piezoelectric vibrating piece shown in FIG. 1 is manufactured, and is a cross-sectional view of the wafer along the line CC in FIG. 9. FIG. 10 is a process diagram when the piezoelectric vibrating piece shown in FIG. 1 is manufactured, and is a cross-sectional view of the wafer along the line CC in FIG. 9. FIG. 10 is a process diagram when the piezoelectric vibrating piece shown in FIG. 1 is manufactured, and is a cross-sectional view of the wafer along the line CC in FIG. 9. FIG. 10 is a process diagram when the piezoelectric vibrating piece shown in FIG. 1 is manufactured, and is a cross-sectional view of the wafer along the line CC in FIG. 9. FIG. 10 is a process diagram when the piezoelectric vibrating piece shown in FIG. 1 is manufactured, and is a cross-sectional view of the wafer along the line CC in FIG. 9. FIG. 10 is a process diagram when the piezoelectric vibrating piece shown in FIG. 1 is manufactured, and is a cross-sectional view of the wafer along the line CC in FIG. 9. FIG. 10 is a process diagram when the piezoelectric vibrating piece shown in FIG. 1 is manufactured, and is a cross-sectional view of the wafer along the line CC in FIG. 9. FIG. 10 is a process diagram when the piezoelectric vibrating piece shown in FIG. 1 is manufactured, and is a cross-sectional view of the wafer along the line CC in FIG. 9. FIG. 10 is a process diagram for manufacturing a piezoelectric vibrating piece showing a case where a photoresist film is displaced on the same wafer, and is a cross-sectional view of the wafer corresponding to the line CC in FIG. 9. FIG. 10 is a process diagram for manufacturing a piezoelectric vibrating piece showing a case where a photoresist film is displaced on the same wafer, and is a cross-sectional view of the wafer corresponding to the line CC in FIG. 9. FIG. 10 is a process diagram for manufacturing a piezoelectric vibrating piece showing a case where a photoresist film is displaced on the same wafer, and is a cross-sectional view of the wafer corresponding to the line CC in FIG. 9. FIG. 10 is a process diagram for manufacturing a piezoelectric vibrating piece showing a case where a photoresist film is displaced on the same wafer, and is a cross-sectional view of the wafer corresponding to the line CC in FIG. 9. 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 process drawing at the time of manufacturing the conventional piezoelectric vibrating piece, and is a cross-sectional view of the wafer corresponding to the CC line of FIG. It is process drawing at the time of manufacturing the conventional piezoelectric vibrating piece, and is a cross-sectional view of the wafer corresponding to the CC line of FIG. It is process drawing at the time of manufacturing the conventional piezoelectric vibrating piece, and is a cross-sectional view of the wafer corresponding to the CC line of FIG. It is process drawing at the time of manufacturing the conventional piezoelectric vibrating piece, and is a cross-sectional view of the wafer corresponding to the CC line of FIG.

Next, an embodiment according to the present invention will be described based on the drawings.
(Piezoelectric vibrator)
FIG. 1 is an external perspective view of a piezoelectric vibrator according to the present invention. FIG. 2 is an internal configuration diagram of the piezoelectric vibrator, and shows a piezoelectric vibrating piece viewed from above with a 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 is formed in a box shape in which a base substrate 2 and a lid substrate 3 are laminated in two layers, and piezoelectric vibration is generated in an internal cavity C. This is a surface-mount type piezoelectric vibrator in which the piece 4 is housed. In FIG. 4, the excitation electrode 15, the extraction electrodes 19 and 20, the mount electrodes 16 and 17, and the weight metal film 21, which will be described later, are omitted for easy understanding of the drawing.

5 is a top view of the piezoelectric vibrating piece constituting the piezoelectric vibrator, FIG. 6 is a bottom view, and FIG. 7 is a cross-sectional view taken along the line BB of FIG.
As shown in FIGS. 5 to 7, the piezoelectric vibrating piece 4 is a tuning fork type vibrating piece formed of a piezoelectric material such as crystal, lithium tantalate, or lithium niobate, and vibrates when a predetermined voltage is applied. To do.
The piezoelectric vibrating reed 4 includes a pair of vibrating arm portions 10 and 11 arranged in parallel, a base portion 12 that integrally fixes the base end sides of the pair of vibrating arm portions 10 and 11, and a pair of vibrating arm portions 10. 11, an excitation electrode 15 comprising a first excitation electrode 13 and a second excitation electrode 14 that vibrate the pair of vibrating arm portions 10, 11, and the first excitation electrode 13 and the first excitation electrode 13. And two mounting electrodes 16 and 17 electrically connected to the two excitation electrodes 14.
Further, the piezoelectric vibrating reed 4 of the present embodiment includes groove portions 18 formed along the longitudinal direction of the vibrating arm portions 10 and 11 on both main surfaces of the pair of vibrating arm portions 10 and 11. The groove portion 18 is formed from the proximal end side of the vibrating arm portions 10 and 11 to the vicinity of the middle.

  The excitation electrode 15 composed of the first excitation electrode 13 and the second excitation electrode 14 is an electrode that vibrates the pair of vibrating arm portions 10 and 11 at a predetermined resonance frequency in a direction approaching or separating from each other. It is formed by patterning on the outer surface of the vibrating arms 10 and 11 while being electrically separated from each other. Specifically, the first excitation electrode 13 is mainly formed on the groove portion 18 of one vibration arm portion 10 and on both side surfaces of the other vibration arm portion 11, and the second excitation electrode 14 is formed on one side. Are formed mainly on both side surfaces of the vibrating arm portion 10 and on the groove portion 18 of the other vibrating arm portion 11.

In addition, the first excitation electrode 13 and the second excitation electrode 14 are electrically connected to the mount electrodes 16 and 17 via the extraction electrodes 19 and 20, respectively, on both main surfaces of the base portion 12. A voltage is applied to the piezoelectric vibrating reed 4 via the mount electrodes 16 and 17.
The excitation electrode 15, the mount electrodes 16 and 17, and the extraction electrodes 19 and 20 described above are made of a conductive film such as chromium (Cr), nickel (Ni), aluminum (Al), or titanium (Ti). It is formed.

  Further, a weight metal film 21 for adjusting (frequency adjustment) to vibrate its own vibration state within a predetermined frequency range is coated on the tips of the pair of vibrating arm portions 10 and 11. The weight metal film 21 is divided into a coarse adjustment film 21a used when the frequency is roughly adjusted and a fine adjustment film 21b used when the frequency is finely adjusted. By adjusting the frequency using the coarse adjustment film 21a and the fine adjustment film 21b, the frequency of the pair of vibrating arm portions 10 and 11 can be kept within the range of the nominal frequency of the device.

  As shown in FIGS. 3 and 4, the piezoelectric vibrating reed 4 configured as described above is bump-bonded to the upper surface of the base substrate 2 using bumps B such as gold. More specifically, bump bonding is performed with a pair of mount electrodes 16 and 17 in contact with two bumps B formed on lead electrodes 36 and 37 (described later) patterned on the upper surface of the base substrate 2. ing. As a result, the piezoelectric vibrating reed 4 is supported in a state of floating from the upper surface of the base substrate 2, and the mount electrodes 16 and 17 and the routing electrodes 36 and 37 are electrically connected to each other.

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

The base substrate 2 described above is a transparent insulating substrate made of a glass material, for example, soda-lime glass, similar to the lid substrate 3, and has a size that can be superimposed on the lid substrate 3 as shown in FIGS. It is formed in a plate shape.
The base substrate 2 is formed with a pair of through holes 30 and 31 penetrating the base substrate 2. At this time, the pair of through holes 30 and 31 are formed so as to be accommodated in the cavity C. More specifically, in the through holes 30 and 31 of the present embodiment, one through hole 30 is formed at a position corresponding to the base 12 side of the mounted piezoelectric vibrating reed 4, and the distal ends of the vibrating arm portions 10 and 11 are formed. The other through hole 31 is formed at a position corresponding to. In the present embodiment, a through hole having a tapered cross section whose diameter gradually decreases from the lower surface to the upper surface of the base substrate 2 will be described as an example. However, the present invention is not limited to this, and the base substrate 2 is straightened. A through hole that penetrates may be used. In any case, it only has to penetrate the base substrate 2.

  The pair of through holes 30 and 31 are formed with a pair of through electrodes 32 and 33 formed so as to fill the through holes 30 and 31. As shown in FIG. 3, the through electrodes 32 and 33 are formed by the cylindrical body 6 and the core member 7 that are integrally fixed to the through holes 30 and 31 by firing. 31 are completely closed to maintain the airtightness in the cavity C, and the external electrodes 38 and 39, which will be described later, and the routing electrodes 36 and 37 are electrically connected.

  The cylinder 6 is obtained by baking paste-like glass frit. The cylindrical body 6 is formed in a cylindrical shape having both ends flat and substantially the same thickness as the base substrate 2. And the core part 7 is distribute | arranged to the center of the cylinder 6 so that the cylinder 6 may be penetrated. In the present embodiment, the outer shape of the cylindrical body 6 is formed in a conical shape (tapered cross section) according to the shape of the through holes 30 and 31. The cylindrical body 6 is fired in a state of being embedded in the through holes 30 and 31, and is firmly fixed to the through holes 30 and 31.

The core material portion 7 described above is a conductive core material formed in a cylindrical shape with a metal material, and both ends are flat like the cylindrical body 6 and have a thickness substantially the same as the thickness of the base substrate 2. Is formed. The core portion 7 is located in the center hole 6 c of the cylindrical body 6 and is firmly fixed to the cylindrical body 6 by firing the cylindrical body 6.
The through electrodes 32 and 33 are ensured to have electrical conductivity through the conductive core portion 7.

  As shown in FIGS. 1 to 4, on the upper surface side of the base substrate 2 (the bonding surface side to which the lid substrate 3 is bonded), a bonding film 35 for anodic bonding and a pair are formed using a conductive material (for example, aluminum). The lead-out electrodes 36 and 37 are patterned. Among these, the bonding film 35 is formed along the periphery of the base substrate 2 so as to surround the periphery of the recess 3 a formed in the lid substrate 3.

The pair of lead-out electrodes 36 and 37 electrically connect one of the through electrodes 32 and 33 to the one mount electrode 16 of the piezoelectric vibrating reed 4 and the other through electrode. 33 and the other mount electrode 17 of the piezoelectric vibrating reed 4 are patterned so as to be electrically connected.
More specifically, the one lead-out electrode 36 is formed directly above the one through electrode 32 so as to be positioned directly below the base 12 of the piezoelectric vibrating piece 4. The other routing electrode 37 is routed from the position adjacent to the one routing electrode 36 along the vibrating arm portions 10 and 11 to the distal end side of the vibrating arm portions 10 and 11, and then the other through electrode 33. It is formed so that it may be located just above.
Bumps B are formed on the pair of lead-out electrodes 36 and 37, and the piezoelectric vibrating reed 4 is mounted using the bumps B. Thereby, one mount electrode 16 of the piezoelectric vibrating reed 4 is electrically connected to one through electrode 32 through one routing electrode 36, and the other mount electrode 17 is passed through the other routing electrode 37 to the other penetration electrode. 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 2. That is, one external electrode 38 is electrically connected to the first excitation electrode 13 of the piezoelectric vibrating reed 4 via one through electrode 32 and one routing electrode 36. The other external electrode 39 is electrically connected to the second excitation electrode 14 of the piezoelectric vibrating reed 4 via the other through electrode 33 and the other routing electrode 37.

  When the piezoelectric vibrator 1 configured in this way is operated, a predetermined drive voltage is applied to the external electrodes 38 and 39 formed on the base substrate 2. As a result, a current can flow through the excitation electrode 15 including the first excitation electrode 13 and the second excitation electrode 14 of the piezoelectric vibrating reed 4, and the predetermined amount is set in a direction in which the pair of vibrating arm portions 10 and 11 are approached and separated. Can be vibrated at a frequency of The vibration of the pair of vibrating arm portions 10 and 11 can be used as a time source, a control signal timing source, a reference signal source, and the like.

(Method for manufacturing piezoelectric vibrating piece)
Next, a method for manufacturing the above-described piezoelectric vibrating piece will be described. In the following description, a case where a plurality of piezoelectric vibrating pieces are manufactured from a wafer mainly made of quartz will be described. FIG. 8 is a flowchart showing a method of manufacturing a piezoelectric vibrating piece, FIGS. 9 to 24 are process diagrams showing a method of manufacturing the piezoelectric vibrating piece, FIG. 9 is a plan view of a wafer, and FIGS. FIG. 6 shows a cross-sectional view of the wafer along the line CC of FIG.
As shown in FIGS. 8 and 10, first, a quartz Lambert rough is sliced at a predetermined angle to form a wafer S having a constant thickness. Subsequently, the wafer S is lapped and roughly processed, and then the work-affected layer is removed by etching, followed by mirror polishing such as polishing to obtain a wafer S having a predetermined thickness (S10).

Next, an outer pattern forming process for forming a wafer mask (first mask) 40, which is an outer pattern for patterning the outer shapes of the plurality of piezoelectric vibrating reeds 4, is performed (S20: first mask forming process). This step will be specifically described.
First, as shown in FIG. 11, after the polishing of the wafer S is prepared, a wafer mask 40 is formed on each surface of the wafer S (S21). As the wafer mask 40, for example, chromium (Cr) is formed to a thickness of several μm.
Next, as shown in FIG. 12, a photoresist film 41 is formed on the wafer mask 40 by spin coating or the like. Thereafter, as shown in FIGS. 13 and 14, the photoresist film 41 has an outer shape equivalent to the outer shape of the piezoelectric vibrating reed 4 in the formation region of the piezoelectric vibrating reed 4 by performing exposure / development by a photolithography technique. (See FIG. 14).

  Then, as shown in FIG. 15, etching (for example, wet etching) is performed using the patterned photoresist film 41 as a mask, and an unmasked wafer mask 40 (for a wafer other than the region where the piezoelectric vibrating reed 4 is formed). The mask 40) is selectively removed (S22). Thereafter, as shown in FIG. 16, the photoresist film 41 is removed after the etching process. Accordingly, as shown in FIGS. 9 and 16, the wafer mask 40 can be patterned into a shape equivalent to the outer shape of the piezoelectric vibrating reed 4. That is, the wafer mask 40 can be patterned following the outer shape of the pair of vibrating arm portions 10 and 11 and the base portion 12. At this time, patterning is performed collectively for the plurality of piezoelectric vibrating reeds 4 formed on the wafer S.

Next, a groove pattern forming step is performed to form a photoresist film (second mask) 42 that becomes a groove pattern for patterning the shape of the groove portions 18 of the plurality of piezoelectric vibrating reeds 4 (S30: second mask forming step). . This step will be specifically described.
First, as shown in FIG. 17, a photoresist film 42 is formed again on the wafer S patterned with the wafer mask 40 (S31). Specifically, first, a material for forming the photoresist film 42 is applied on both surfaces of the wafer S so as to cover the wafer mask 40 by spin coating. At this time, a wafer mask 40 is formed in the formation region of the piezoelectric vibrating reed 4 on the wafer S. Since the wafer mask 40 is a very thin film having a film thickness of several μ, When the forming material is applied to the entire surface of the wafer S by the spin coating method, the progress of the forming material of the photoresist film 42 is not hindered by the wafer mask 40. That is, before the wafer S is patterned into the outer shape of the piezoelectric vibrating piece 4, a uniform film is rapidly formed over the entire surface of the wafer S by applying a material for forming the photoresist film 42 by spin coating. be able to. The material for forming the photoresist film 42 can be applied by a spray coating method or the like in addition to the spin coating method.

  Next, as shown in FIG. 18, the above-described photoresist film 42 is patterned by photolithography (S32). At this time, as shown in FIG. 19, the patterning is performed so that the region where the groove 18 is formed has an opening 42 a and is larger than the outer shape of the piezoelectric vibrating reed 4 (wafer mask 40). Specifically, the opening 42a of the photoresist film 42 is patterned in the formation region of the groove 18 so as to be equal to the length in the width direction and the length direction of the groove 18 to be formed. On the other hand, the outer shape of the photoresist film 42 is patterned larger in the formation region of the piezoelectric vibrating piece 4 than in the width direction and the length direction of the piezoelectric vibrating piece 4 to be formed. Therefore, when the photoresist film 42 is overlapped at a desired position, that is, when the center in the width direction of the wafer mask 40 and the center in the width direction of the photoresist film 42 coincide with each other, The outer peripheral portion is in a state of reaching the main surface of the wafer S from the outer peripheral portion of the wafer mask 40 covering the side surface.

In this case, at least in the formation region of the vibrating arm portions 10 and 11, the expansion margin of the photoresist film 42 with respect to the wafer mask 40 (piezoelectric vibrating piece 4) is from the outer periphery of the wafer mask 40 in the width direction and the length direction. It is preferable to set a large value in the range of 3 μm to 10 μm. That is, if the enlargement margin of the photoresist film 42 with respect to the wafer mask 40 is smaller than 3 μm, the outer peripheral portion of the wafer mask 40 becomes the photoresist when there is a deviation between the two due to the limit of the overlay accuracy during patterning. Since there exists a possibility of exposing from the film | membrane 41, it is not preferable. On the other hand, if the thickness is larger than 10 μm, the etchant does not go around between the photoresist film 42 that goes around the side surface of the wafer mask 40 and the wafer S in the outer shape forming step (S40) to be described later. This is not preferable because there is a possibility that patterning to a desired outer shape cannot be performed.
On the other hand, the enlargement margin of the photoresist film 42 from the outer peripheral edge of the wafer mask 40 is set to be longer in the range of 3 μm to 10 μm in the length direction and width direction of the wafer mask 40, which will be described later. The outer peripheral portion of the wafer mask 40 can be reliably covered with the photoresist film 42 within a range that does not affect the outer shape forming process. The photoresist film 42 is preferably formed to be long in the width direction and the length direction of the wafer mask 40 as in the present embodiment, but at least the width direction having a large influence on vibration characteristics is at least the wafer. It suffices if it is formed longer than the mask 40 for use. At this point, the groove pattern forming process is completed.

Next, an outer shape forming step of patterning the outer shapes of the plurality of piezoelectric vibrating reeds 4 is performed (S40).
First, as shown in FIG. 20, both surfaces of the wafer S are wet etched using the patterned wafer mask 40 as a mask. As a result, the region not masked by the wafer mask 40 can be selectively removed to form the outer shape of the piezoelectric vibrating reed 4 excluding the groove 18. In the present embodiment, the photoresist film 42 is formed on the wafer S so as to cover the outer peripheral portion and the side surface of the wafer mask 40. However, since the photoresist film 42 and the wafer S are not adhesive, An etchant enters between the photoresist film 42 and the wafer S. This reaches the outer peripheral portion of the wafer mask 40 and has no effect on the etching. That is, the wafer S can be reliably etched into a desired outer shape (the outer shape of the piezoelectric vibrating piece 4) following the outer shape of the wafer mask 40. The plurality of piezoelectric vibrating reeds 4 are in a state of being connected to the wafer S via a connecting portion (not shown) until a subsequent cutting step (S110) is performed.

Then, as shown in FIG. 21, the wafer mask 40 exposed from the opening 42a (the region where the groove 18 is formed) of the photoresist film 42 is removed by wet etching (S50). Specifically, the wafer mask 40 in the region where the groove 18 is formed is selectively removed by etching using the photoresist film 42 as a mask.
Subsequently, as shown in FIG. 22, the groove portion 18 is formed by performing wet etching on both surfaces of the wafer S using the re-patterned wafer mask 40 and the photoresist film 42 as a mask (S60: groove portion forming step). . As a result, the region not masked by the wafer mask 40 can be selectively removed, and the groove portion 18 can be formed on the vibrating arm portions 10 and 11 of the piezoelectric vibrating piece 4.

Next, as shown in FIG. 23, after the groove portion 18 is formed, the photoresist film 42 used as a mask is removed (S70), and then the wafer mask 40 is removed as shown in FIG. 24 (S80). Thus, as shown in FIG. 24, the plurality of piezoelectric vibrating reeds 4 having the groove portions 18 on the vibrating arm portions 10 and 11 are formed in a state of being connected to the wafer S.
Then, in a state where the plurality of piezoelectric vibrating reeds 4 are connected to the wafer S, an electrode forming process for forming the excitation electrode 15, the extraction electrodes 19 and 20 and the mount electrodes 16 and 17 on the outer surface of the piezoelectric vibrating reed 4 is performed. (S90).

In addition, after the electrode forming step is finished, a weight metal film 21 (for example, silver or gold) made of a frequency adjusting coarse adjustment film 21a and a fine adjustment film 21b is coated on the tips of the pair of vibrating arms 10 and 11. (S100).
Finally, a connecting step that connects the wafer S and the piezoelectric vibrating piece 4 is cut, and a cutting process is performed in which the plurality of piezoelectric vibrating pieces 4 are separated from the wafer S into smaller pieces (S110). Thereby, a plurality of piezoelectric vibrating reeds 4 on which the excitation electrode 14, the extraction electrodes 19 and 20 and the mount electrodes 16 and 17 are formed can be manufactured from the wafer S at a time.

  Here, a case where the overlay accuracy of the photoresist film 42 is shifted will be described. 25 to 28 are process diagrams when manufacturing the piezoelectric vibrating piece showing the case where the photoresist film is displaced on the same wafer, and are sectional views of the wafer corresponding to the line CC in FIG. . In the following description, steps after the above-described groove pattern forming step (S30) will be described.

  When a deviation occurs in the overlay accuracy of the photoresist film 42 at the time of forming the groove pattern, for example, as shown in FIG. 25, one end in the width direction of the photoresist film 42 is one end in the width direction of the wafer mask 40. On the other hand, the other end side of the photoresist film 42 reaches the main surface of the wafer S while covering the other end side in the width direction of the wafer mask 40. Therefore, the center in the width direction of the opening 42 a of the photoresist film 42 is shifted from the center in the width direction of the wafer mask 40 toward the other end side.

However, in the present embodiment, the enlargement margin of the photoresist film 42 from the outer peripheral edge of the wafer mask 40 is set longer than the wafer mask 40 in the range of 3 μm to 10 μm, and therefore the photoresist film 42. Even when there is a deviation in the overlay accuracy, the wafer mask 40 can be covered with the photoresist film 42.
In addition, as shown in FIG. 26, since the etchant enters between the photoresist film 42 and the wafer S also in the outer shape forming process, the wafer S is formed in a desired outer shape following the outer shape of the wafer mask 40. Etching can be reliably performed into the shape (outer shape of the piezoelectric vibrating piece 4). Thereafter, the wafer mask 40 exposed from the opening 42a (the formation region of the groove 18) of the photoresist film 42 is removed by wet etching. Therefore, the opening portion of the wafer mask 40 is formed closer to the other end side than the center in the width direction.

  Then, as shown in FIG. 27, the groove 18 is formed by performing wet etching on both surfaces of the wafer S using the wafer mask 40 and the photoresist film 42 as a mask. At this time, the groove portion 18 is slightly displaced as compared with the case where the photoresist film 42 is overlapped at a desired position, but the outer peripheral portion of the piezoelectric vibrating reed 4 is surely secured by the wafer mask 40 and the photoresist film 42. Protected. That is, even when the overlay accuracy of the photoresist film 42 is shifted on the same wafer S, the volume of the piezoelectric vibrating reed 4 itself varies between the piezoelectric vibrating reeds 4 as shown in FIG. Therefore, the same vibration characteristic can be exhibited by each piezoelectric vibrating piece 4.

As described above, in this embodiment, in the groove pattern forming step (S30), the opening portion 42a is formed in the formation region of the groove portion 18 on the wafer mask 40, and the outer shape of the piezoelectric vibrating reed 4 (wafer mask 40). A larger photoresist film 42 is formed.
According to this configuration, since the photoresist film 42 is formed larger than the photoresist film 41, even if the overlay accuracy of the photoresist film 42 varies, the photoresist film 42 The probability that the wafer mask 40 excluding the formation region (opening 42a) of the groove 18 is completely covered increases. That is, it is possible to prevent the formation region of the piezoelectric vibrating reed 4 from being exposed from the photoresist film 42. Thereby, when the wafer mask 40 exposed from the opening 42a is removed, the outer peripheral portion of the wafer mask 40 is not removed. Therefore, when forming the groove 18, the groove 18 can be formed without removing the outer peripheral portion of the piezoelectric vibrating reed 4. As a result, the piezoelectric vibrating reed 4 can be formed in a desired outer shape. That is, variation in the outer shape of the piezoelectric vibrating reed 4 due to variation in overlay accuracy can be effectively suppressed.
Accordingly, it is possible to manufacture the high-performance piezoelectric vibrator 1 having a stable vibration characteristic on the wafer S in a lump by suppressing the frequency variation of the piezoelectric vibrating reed 4. And since the piezoelectric vibrator 1 of this embodiment is provided with the piezoelectric vibrating reed 4 manufactured by the manufacturing method mentioned above, the small and high-performance piezoelectric vibrator 1 can be provided.
Further, according to the present embodiment, since the outer shape of the photoresist film 42 is only formed larger than the outer shape of the piezoelectric vibrating piece 4, after suppressing a decrease in manufacturing efficiency and an increase in manufacturing cost, The piezoelectric vibrating reed 4 having stable vibration characteristics can be provided.

(Oscillator)
Next, an oscillator according to an embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 29, the oscillator 100 according to the present embodiment is configured such that the piezoelectric vibrator 1 is 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 above-described 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 reed 4 in the piezoelectric vibrator 1 vibrates. This vibration is converted into an electric signal by the piezoelectric characteristics of the piezoelectric vibrating piece 4 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.

  As described above, according to the oscillator 100 of the present embodiment, since the piezoelectric vibrator 1 is downsized and improved in quality, the oscillator 100 itself can be similarly downsized and improved in quality. . In addition to this, a stable and highly accurate frequency signal can be obtained.

(Electronics)
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. 30, 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 4 vibrates, and this 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, since the piezoelectric vibrator 1 is downsized and improved in quality, the portable information device itself is similarly downsized and improved in quality. be able to. In addition to this, it is possible to display highly accurate clock information that is stable over a long period of time.

(Radio watch)
Next, an embodiment of a radio timepiece according to the present invention will be described with reference to FIG.
As shown in FIG. 31, the radio timepiece 130 of the present embodiment includes the piezoelectric vibrator 1 electrically connected to the filter unit 131. The radio timepiece 130 receives a standard radio wave including timepiece information and is accurate. 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 in 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 described above.

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 piezoelectric vibrator 1 is downsized and improved in quality, the radio-controlled timepiece itself can be similarly reduced in size and improved in quality. it can. In addition to this, it is possible to count time stably and with high accuracy over a long period of time.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, in the above-described embodiment, the surface mount type piezoelectric vibrator 1 is described as an example of the piezoelectric vibrator, but the piezoelectric vibrator 1 is not limited thereto. For example, the present invention can be applied to a cylinder package type piezoelectric vibrator and a ceramic package type piezoelectric vibrator. Further, the cylinder package type piezoelectric vibrator 1 may be further solidified with a mold resin portion to form a surface mount vibrator.

The piezoelectric vibrating reed 4 described above can be manufactured by various manufacturing methods other than the manufacturing method described above. For example, in the above-described embodiment, the case where the outer shape forming step (S40) and the groove portion forming step (S50) are successively performed after the photoresist film 42 is formed has been described. However, the wafer is formed before the photoresist film 42 is formed. The outer shape forming process may be performed using only the mask 40 for the mask. In this case, after the outer shape of the piezoelectric vibrating reed 4 excluding the groove 18 is formed, the photoresist film 42 is formed and the groove forming process is performed.
Further, in the above-described embodiment, the case where wet etching is mainly performed at the time of each etching process has been described, but dry etching can also be employed.

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric vibrator 4 ... Piezoelectric vibration piece 10, 11 ... Vibrating arm part (vibration area | region) 12 ... Base 18 ... Groove part 40 ... Mask for wafers (1st mask) 42 ... Photoresist film (2nd mask) 42a ... Opening DESCRIPTION OF SYMBOLS 100 ... Oscillator 101 ... Integrated circuit of oscillator 110 ... Portable information device (electronic device) 113 ... Timekeeping part of electronic device 130 ... Radio clock 131 ... Filter unit of radio clock

Claims (10)

A pair of vibrating arm portions arranged in parallel, a base portion for integrally fixing the base end sides of the pair of vibrating arm portions, and a longitudinal direction of the vibrating arm portion on the pair of vibrating arm portions, respectively A piezoelectric vibrating reed manufacturing method for manufacturing a piezoelectric vibrating reed provided with a formed groove from a wafer,
A first mask for forming an outer shape of the piezoelectric vibrating piece and a groove is formed in the formation region of the piezoelectric vibrating piece on the wafer, the outer shape being equivalent to the outer shape of the piezoelectric vibrating piece. 1 mask formation process;
A second mask forming step of forming a second mask having an opening in the groove forming region on the first mask;
Using the second mask as a mask, removing the first mask exposed from the opening, and
In the second mask forming step, the second mask having an outer shape larger than the outer shape of the piezoelectric vibrating piece is formed.   2. The method of manufacturing a piezoelectric vibrating piece according to claim 1, wherein, in the second mask forming step, an expansion margin of the second mask from an outer peripheral edge of the piezoelectric vibrating piece is set in a range of 3 μm to 10 μm. .   3. The method of manufacturing a piezoelectric vibrating piece according to claim 2, wherein the second mask is formed larger than the piezoelectric vibrating piece along at least a short direction perpendicular to the longitudinal direction of the piezoelectric vibrating piece. Forming the outer shape of the piezoelectric vibrating piece from the wafer using the first mask as a mask after the second mask forming step;
4. The method of manufacturing a piezoelectric vibrating piece according to claim 1, further comprising: forming the groove using the first mask as a mask. 5.   The method of manufacturing a piezoelectric vibrating piece according to claim 4, wherein the step of forming the outer shape of the piezoelectric vibrating piece is performed by wet etching.   A piezoelectric vibrating piece manufactured by the method for manufacturing a piezoelectric vibrating piece according to claim 1.   A piezoelectric vibrator comprising the piezoelectric vibrating piece according to claim 6.   The oscillator according to claim 7, wherein the piezoelectric vibrator 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 timer unit.   A radio wave timepiece, wherein the piezoelectric vibrator according to claim 7 is electrically connected to a filter unit.

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