JP2013080990A - Manufacturing method of piezoelectric vibration piece, manufacturing apparatus of piezoelectric vibration piece, piezoelectric vibrator, oscillator, electronic apparatus, and atomic clock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a piezoelectric vibration piece which suppresses the temperature rise during the deposition of an insulation film and suppresses metal diffusion of an electrode, and to provide a piezoelectric vibrator, an oscillator, an electronic apparatus, and an atomic clock which include the piezoelectric vibration piece manufactured in this method.SOLUTION: A passivation film deposition process is carried out using a sputtering apparatus 70 including a target 77 and a rotation drum 71 that may rotate. The passivation film deposition process includes: wafer attachment process where a wafer W is attached to an outer peripheral surface 71a of the rotation drum 71; and a rotation deposition process where the rotation drum 71 is rotated so that the wafer W passes a position facing the target 77 to deposit the passivation film. The rotation deposition process is characterized in that the rotation drum 71 is rotated so that the wafer W passes the position facing the target 77 multiple times thereby depositing the passivation film.

Description

  The present invention relates to a piezoelectric vibrating piece manufacturing method, a piezoelectric vibrating piece manufacturing apparatus, a piezoelectric vibrator, an oscillator, an electronic device, and a radio timepiece.

  In cellular phones and portable information terminal devices, piezoelectric vibrators using quartz or the like are used as time sources, timing sources of control signals, reference signal sources, and the like. Various piezoelectric vibrators of this type are provided, and a piezoelectric vibrator in which a so-called AT-cut type piezoelectric vibrating piece or tuning-fork type piezoelectric vibrating piece is enclosed in a package is known.

For example, a tuning-fork type piezoelectric vibrating piece has a thin plate shape having a pair of vibrating arm portions arranged side by side in the width direction and a base portion that integrally fixes the base end sides in the longitudinal direction of the pair of vibrating arm portions. It is a crystal piece.
A pair of excitation electrodes is formed on the main surface of each vibrating arm portion of the piezoelectric vibrating piece with a predetermined gap therebetween. A pair of mount electrodes that are electrically connected to the pair of excitation electrodes are formed on the main surface of the base.

The excitation electrode is, for example, a single layer film made of chromium or the like having good adhesion to quartz, and is covered with an insulating film for the purpose of preventing a short circuit between the pair of excitation electrodes.
The mount electrode is a multilayer film including a base layer such as chromium and a finish layer such as gold having excellent wettability with respect to solder or the like. The mount electrode is exposed from the insulating film, and the piezoelectric vibrating piece is mounted on the package by being joined to the internal electrode of the package via solder or the like.

The insulating film is formed of an insulating material such as silicon oxide (SiO ₂ ), for example, and is formed by a film forming method such as a sputtering method or a CVD method.
By the way, when an insulating film is formed by a sputtering method, a CVD method, or the like, the temperature of the substrate to be formed becomes very high (for example, about 1000 ° C. by the CVD method), which may damage the substrate or the like. . Therefore, a method for forming an insulating film without raising the temperature of the substrate as much as possible has been proposed (see, for example, Patent Document 1 and Patent Document 2).

In Patent Document 1, an insulating film is formed by sputtering a silicon target using carbon dioxide (CO ₂ ) or a mixed gas of rare gas and carbon dioxide as a plasma generating gas. According to Patent Document 1, since Si—O bonding can be performed in plasma, an insulating film can be formed at a substrate temperature of about 200 ° C. without requiring a high temperature.

In Patent Document 2, when the SiO ₂ insulating film is deposited on the substrate by ECR plasma, the temperature of the substrate is controlled in the range of 200 to 400 ° C., and the supply rate of the supply gas is 1.5 sccm or less. . According to Patent Document 2, it is said that the film deposition temperature can be reduced and a highly reliable high quality film can be obtained.

JP-A-8-269706 JP-A-9-306906

However, when an insulating film is formed on the piezoelectric vibrating piece, there are the following problems.
As described above, the mount electrode of the piezoelectric vibrating piece is formed by laminating a base layer such as chromium and a finishing layer such as gold. Here, when the mount electrode reaches a high temperature, so-called metal diffusion occurs in which the metals melt between the underlayer and the finishing layer.

  As the metal diffusion proceeds, the material of the underlayer is deposited on the surface of the finishing layer, which may deteriorate the wettability of the finishing layer to solder or the like. As a result, when the mount electrode is joined to the internal electrode of the package via solder or the like, the mounting strength of the piezoelectric vibrating piece may be reduced. In the prior art, a method of forming an insulating film while suppressing a temperature rise to about 200 ° C. to 400 ° C. has been proposed. In particular, further suppression of the temperature rise is necessary to suppress metal diffusion.

  Accordingly, the present invention provides a method for manufacturing a piezoelectric vibrating piece capable of suppressing a temperature rise during the formation of an insulating film and suppressing metal diffusion of an electrode, and a piezoelectric vibrator and an oscillator including the piezoelectric vibrating piece manufactured by this method. An object is to provide an electronic device and a radio timepiece.

  In order to solve the above problems, a method of manufacturing a piezoelectric vibrating piece according to the present invention includes a piezoelectric plate formed from a wafer, an excitation electrode that vibrates the piezoelectric plate, and a metal film electrically connected to the excitation electrode. A method of manufacturing a piezoelectric vibrating piece having a stacked mount electrode, wherein an insulating film covering at least the excitation electrode is sputtered on at least one of the first surface and the second surface of the wafer. An insulating film forming step for forming a film by a method, wherein the insulating film forming step uses a sputtering apparatus including a target that is a raw material of the insulating film and a rotating drum that can rotate around a rotation axis. The insulating film forming step includes a wafer attaching step of attaching the wafer to the outer peripheral surface of the rotary drum, and the rotating drum so that the wafer passes through a position facing the target. A rotating film forming step of rotating the film to form the insulating film, and the rotating film forming step rotates the rotating drum so that the wafer passes a position facing the target a plurality of times. Thus, the insulating film is formed.

According to the present invention, in the rotational film formation step, the insulating film can be formed in a plurality of times by passing the wafer facing the target a plurality of times. Thereby, since the time per time when the wafer faces the target can be shortened, an increase in the temperature of the wafer during the formation of the insulating film can be suppressed. In addition, since the wafer temperature decreases after the wafer passes through the position facing the target and before the wafer passes through the position facing the target again, an increase in the wafer temperature can be suppressed. Therefore, metal diffusion of the mount electrode can be prevented.
Further, in the rotating film forming process, the side surface of the piezoelectric plate can be made to face the target before and after the wafer faces the target during the rotation of the rotating drum. Therefore, an insulating film can be reliably formed on the side surface of the piezoelectric plate in addition to the main surface of the piezoelectric plate. In particular, in the case of a tuning-fork type piezoelectric plate in which the vibrating arm portion is connected to the base portion, an insulating film can be reliably formed on the other portion formed at the connecting portion between the vibrating arm portion and the base portion.

  Further, the mount electrode is characterized in that a finishing layer mainly composed of gold is provided on the outermost layer of the laminated metal film.

  According to the present invention, since the piezoelectric vibrating piece is manufactured by a manufacturing method capable of suppressing metal diffusion, it is possible to prevent the material of the lower metal film from being deposited on the surface of the finishing layer. Thereby, the good wettability of the finishing layer mainly composed of gold can be maintained, which is particularly suitable for manufacturing a piezoelectric vibrating piece having a finishing layer mainly composed of gold.

  The sputtering apparatus includes a wafer fixing jig capable of mounting a plurality of the wafers, and the wafer mounting step includes mounting the plurality of wafers on the wafer fixing jig, and the plurality of wafers together with the wafer fixing jig. Is attached to the rotating drum.

  According to the present invention, since a plurality of wafers can be easily attached to the rotating drum in a short time, the number of steps in the wafer attaching process can be shortened.

  Further, the wafer fixing jig has an opening that exposes the first surface and the second surface of the wafer, and the insulating film forming step includes performing the rotational film forming step and then performing the rotation film forming step. The rotating film forming step is performed again by inverting the front and back of the first surface and the second surface of the plurality of wafers together with the fixing jig.

  According to the present invention, since the wafer fixing jig has openings that expose the first surface and the second surface of the wafer, the wafer fixing jig can be fixed by reversing the front and back of the plurality of wafers together with the wafer fixing jig. An insulating film can be formed on the first surface and the second surface of the wafer without removing the wafer from the jig. In addition, the front and back of a plurality of wafers can be easily reversed at a time. Therefore, since the insulating film can be efficiently formed on the first surface and the second surface of the plurality of wafers, the number of steps of the insulating film forming process can be shortened.

  Further, the temperature of the wafer in the insulating film forming step is 100 ° C. or less.

  According to the present invention, the insulating film can be formed in a state where the wafer temperature is much lower than that of the conventional sputtering method. Therefore, metal diffusion of the mount electrode can be reliably prevented.

  The piezoelectric vibrating piece manufacturing apparatus of the present invention is formed by laminating a piezoelectric plate formed from a wafer, an excitation electrode for vibrating the piezoelectric plate, and a metal film electrically connected to the excitation electrode. Sputtering apparatus for forming a piezoelectric vibrating piece having a mount electrode, wherein an insulating film covering at least the excitation electrode is formed on at least one of the first surface and the second surface of the wafer by a sputtering method. The sputtering apparatus includes a target that is a raw material of the insulating film and a rotating drum that can rotate around a rotation axis, and the wafer is attached to an outer peripheral surface of the rotating drum, and the rotating drum Is formed so as to pass through the position facing the target a plurality of times.

According to the present invention, the insulating film can be formed in a plurality of times by passing the wafer multiple times through the position facing the target. Thereby, since the time per time when the wafer faces the target can be shortened, an increase in the temperature of the wafer during the formation of the insulating film can be suppressed. In addition, since the wafer temperature decreases after the wafer passes through the position facing the target and before the wafer passes through the position facing the target again, an increase in the wafer temperature can be suppressed. Therefore, it is possible to provide a sputtering apparatus that can prevent metal diffusion of the mount electrode.
Further, the side surface of the piezoelectric plate can be made to face the target before and after the wafer faces the target during the rotation of the rotating drum. Therefore, an insulating film can be reliably formed on the side surface of the piezoelectric plate in addition to the main surface of the piezoelectric plate.

  In addition, a wafer fixing jig that is attached to the outer peripheral surface of the rotating drum in a state where a plurality of the wafers are attached is provided, and the wafer fixing jig exposes the first surface and the second surface of the wafer. It is characterized by having an opening.

According to the present invention, a plurality of wafers can be easily attached to a rotating drum in a short time.
Further, since the wafer fixing jig has openings that expose the first surface and the second surface of the wafer, the wafer fixing jig can be moved from the wafer fixing jig to the wafer by reversing the front and back of the plurality of wafers together with the wafer fixing jig. An insulating film can be formed on the first surface and the second surface of the wafer without removing. In addition, the front and back of a plurality of wafers can be easily reversed at a time. Therefore, it is possible to provide a sputtering apparatus that can efficiently form an insulating film on the first and second surfaces of a plurality of wafers.

  In addition, the piezoelectric vibrator of the present invention includes a piezoelectric vibrating piece manufactured by the manufacturing method described above.

  According to the present invention, since the piezoelectric vibrating piece is manufactured by the above manufacturing method capable of preventing metal diffusion of the mount electrode, the lower layer metal film material does not precipitate on the surface of the mount electrode. Therefore, since the wettability of the mount electrode is maintained well, a piezoelectric vibrator in which the mounting strength of the piezoelectric vibrating piece is ensured can be obtained.

The oscillator according to the present invention is characterized in that the above-described piezoelectric vibrator is electrically connected to an integrated circuit as an oscillator.
The electronic apparatus according to the present invention is characterized in that the above-described piezoelectric vibrator is electrically connected to a time measuring unit.
The radio-controlled timepiece of the present invention is characterized in that the above-described piezoelectric vibrator is electrically connected to a filter unit.

  According to the oscillator, electronic device, and radio timepiece of the present invention, since the piezoelectric vibrator having the mounting strength of the piezoelectric vibrating piece is ensured, a highly reliable oscillator, electronic device, and radio timepiece can be provided.

According to the present invention, in the rotational film formation step, the insulating film can be formed in a plurality of times by passing the wafer facing the target a plurality of times. Thereby, since the time per time when the wafer faces the target can be shortened, an increase in the temperature of the wafer during the formation of the insulating film can be suppressed. In addition, since the wafer temperature decreases after the wafer passes through the position facing the target and before the wafer passes through the position facing the target again, an increase in the wafer temperature can be suppressed. Therefore, metal diffusion of the mount electrode can be prevented.
In the rotating film forming process, the side surface of the piezoelectric plate can be opposed to the target before and after the first surface or the second surface of the wafer is opposed to the target during the rotation of the rotating drum. Therefore, an insulating film can be reliably formed on the side surface of the piezoelectric plate in addition to the main surface of the piezoelectric plate. In particular, in the case of a tuning-fork type piezoelectric plate in which the vibrating arm portion is connected to the base portion, an insulating film can be reliably formed on the other portion formed at the connecting portion between the vibrating arm portion and the base portion.

It is a top view of a piezoelectric vibrating piece. It is sectional drawing along the AA line of FIG. It is an enlarged perspective view of the part. It is an external appearance perspective view of a cylinder package type piezoelectric vibrator. It is sectional drawing along the BB line of FIG. It is a flowchart of the manufacturing process of a piezoelectric vibrating piece. It is explanatory drawing of an external shape formation process. It is sectional drawing along CC line of FIG. 7 in an electrode formation process. It is an external appearance perspective view of a sputtering device. It is a top view of a rotating drum. It is a front view of a wafer fixing jig. It is sectional drawing along the DD line of FIG. It is explanatory drawing of a wafer attachment process. It is explanatory drawing of a rotation film-forming process. It is sectional drawing of the mount electrode at the time of a rotation film-forming process. 1 is an external perspective view of a surface mount type piezoelectric vibrator. FIG. It is an internal block diagram of a surface-mount type piezoelectric vibrator, and is a plan view in a state where a lid substrate is removed. It is sectional drawing in the EE line | wire of FIG. FIG. 17 is an exploded perspective view of the piezoelectric vibrator shown in FIG. 16. It is a block diagram which shows one Embodiment of an oscillator. It is a lineblock diagram showing one embodiment of electronic equipment. It is a block diagram which shows one Embodiment of a radio timepiece.

(Piezoelectric vibrating piece)
First, a piezoelectric vibrating piece according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a plan view of the piezoelectric vibrating piece 4. In the following description, the front surface in FIG. 1 is referred to as a first surface F, and the back surface in FIG. 1 is referred to as a second surface S.
FIG. 2 is a cross-sectional view taken along the line AA of FIG.
As shown in FIG. 1, the piezoelectric vibrating reed 4 of this embodiment is a tuning fork type vibrating reed formed from a piezoelectric material such as crystal, lithium tantalate, or lithium niobate, and when a predetermined voltage is applied. It will vibrate. The piezoelectric vibrating reed 4 includes a pair of vibrating arm portions 10 and 11 (first vibrating arm portion 10 and second vibrating arm portion 11) arranged in parallel, and base ends of the pair of vibrating arm portions 10 and 11. And a groove portion 18 formed on the first surface F and the second surface S of the pair of vibrating arm portions 10 and 11. The groove portion 18 is formed from the base end side of the vibrating arm portions 10 and 11 to the vicinity of the middle along the longitudinal direction of the vibrating arm portions 10 and 11.

FIG. 3 is an enlarged perspective view of the portion 25.
As shown in FIG. 3, the base portion 12 is adjacent to the vibrating arm portions 10 and 11, and one end sides of the vibrating arm portions 10 and 11 are connected and supported. A connecting portion between the base portion 12 and the vibrating arm portions 10 and 11 is formed with a portion 25 surrounded by the base portion 12, the inner side surface 10 b of the vibrating arm portion 10 and the inner side surface 11 b of the vibrating arm portion 11. Moreover, the part 25 is formed in the planar view substantially U-shape.

  As shown in FIG. 1, the piezoelectric vibrating reed 4 is mounted on the outer surfaces of the pair of vibrating arms 10 and 11 and the mount electrodes 16 and 17 formed on the base 12 for mounting the piezoelectric vibrating reed 4 on a package. An excitation electrode 15 comprising a first excitation electrode 13 and a second excitation electrode 14 formed to vibrate the pair of vibrating arm portions 10 and 11, mount electrodes 16 and 17, the first excitation electrode 13 and the second excitation electrode 13. It has extraction electrodes 19 and 20 that are electrically connected to the excitation electrode 14.

  The mount electrodes 16 and 17 are laminated films of chromium and gold. After a chromium film having good adhesion to crystal is formed as a base layer 84a (see FIG. 5), a gold thin film is formed on the surface of the finish layer 84b ( (See FIG. 5). However, the present invention is not limited to this. For example, a gold thin film may be formed as the finishing layer 84b after nickel, aluminum, titanium, or the like is formed as the base layer 84a.

  The excitation electrode 15 is an electrode that vibrates the pair of vibrating arm portions 10 and 11 at a predetermined resonance frequency in a direction toward or away from each other. The first excitation electrode 13 and the second excitation electrode 14 constituting the excitation electrode 15 are formed by being patterned on the outer surfaces of the pair of vibrating arm portions 10 and 11 while being electrically separated from each other. .

  Specifically, as shown in FIG. 2, the first excitation electrode 13 is mainly formed in the groove portion 18 of the first vibrating arm portion 10, on the outer surface 11 a of the second vibrating arm portion 11, and the second Is formed on the inner side surface 11 b of the vibrating arm portion 11. The second excitation electrode 14 is formed mainly in the groove portion 18 of the second vibrating arm portion 11, on the outer surface 10 a of the first vibrating arm portion 10, and on the inner side surface 10 b of the first vibrating arm portion 10. Has been. 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 on the first surface F and the second surface S of the base 12, respectively. ing.

  Further, as shown in FIG. 3, the first excitation electrode 13 formed on the inner side surface 11 b of the second vibrating arm portion 11 and the first excitation electrode 13 formed on the inner side surface 10 b of the first vibrating arm portion 10. The second excitation electrode 14 is opposed to the second excitation electrode 14 with the portion 25 interposed therebetween. Further, the first excitation electrode 13 and the second excitation electrode 14 are formed on a part of the surface of the portion 25, and are patterned in a state of being electrically separated in the portion 25.

  As shown in FIG. 1, the excitation electrode 15 and the extraction electrodes 19 and 20 are formed of a single layer film of chromium of the same material as the base layer of the mount electrodes 16 and 17. Thereby, the excitation electrode 15 and the extraction electrodes 19 and 20 can be formed simultaneously with the formation of the underlying layers of the mount electrodes 16 and 17. However, the present invention is not limited to this. For example, the excitation electrode 15 and the extraction electrodes 19 and 20 may be formed of nickel, aluminum, titanium, or the like. Excitation electrodes 13 and 14 and extraction electrodes 19 and 20 are covered with a passivation film 24 (corresponding to “insulating film” in the claims), which will be described later.

  A weight metal film 21 for adjusting (frequency adjustment) so as to vibrate within a predetermined frequency range is coated on the tip 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.

(Passivation film)
The piezoelectric vibrating reed 4 includes a passivation film 24 that covers the excitation electrodes 13 and 14 and the extraction electrodes 19 and 20. The passivation film 24 is an insulating film made of an electrically insulating material such as SiO ₂ . The passivation film 24 is formed by sputtering using the sputtering apparatus 70 (see FIG. 9) described later after forming the mount electrodes 16 and 17, the excitation electrodes 13 and 14, and the extraction electrodes 19 and 20 on the piezoelectric vibrating piece 4. The film is formed by the method.

The passivation film 24 is formed so as to cover the excitation electrodes 13 and 14 and the extraction electrodes 19 and 20 in a region excluding the formation region of the mount electrodes 16 and 17 and the weight metal film 21.
Specifically, the passivation film 24 is formed so as to cover the excitation electrodes 13 and 14 and the extraction electrodes 19 and 20 in the vibrating arm portions 10 and 11 and the base portion 12. Thereby, the passivation film 24 prevents a short circuit between the excitation electrodes 13 and 14 and the extraction electrodes 19 and 20.
Further, as shown in FIG. 2, the passivation film 24 is formed so as to cover the excitation electrodes 13 and 14 on the outer side surfaces 10 a and 11 a and the inner side surfaces 10 b and 11 b of the vibrating arm portions 10 and 11. Thereby, the passivation film 24 prevents a short circuit between the excitation electrodes 13 and 14 facing each other formed on the inner side surfaces 10 b and 11 b of the vibrating arm portions 10 and 11.
Further, as shown in FIG. 3, the passivation film 24 is formed in the portion 25 so as to cover the excitation electrodes 13 and 14. This prevents short-circuiting of the excitation electrodes 13 and 14 even in the narrow portion 25.

(Cylinder package type piezoelectric vibrator)
Next, a cylinder package type piezoelectric vibrator including the above-described piezoelectric vibrating piece 4 will be described.
FIG. 4 is an external perspective view of a cylinder package type piezoelectric vibrator 51.
FIG. 5 is a sectional view taken along line BB in FIG.
As shown in FIG. 4, the piezoelectric vibrator 51 is a cylinder package type piezoelectric vibrator 51, and includes a tuning fork-type piezoelectric vibrating piece 4, a plug 52 on which the piezoelectric vibrating piece 4 is mounted, and a piezoelectric together with the plug 52. And a case 53 that hermetically seals the resonator element 4.

  The case 53 is formed in a bottomed cylindrical shape, and is press-fitted into an outer periphery of a stem 54 (to be described later) of the plug 52 with the piezoelectric vibrating reed 4 housed therein, and is fixedly fitted. The case 53 is press-fitted in a vacuum atmosphere, and the space surrounding the piezoelectric vibrating reed 4 in the case 53 is kept in a vacuum.

The plug 52 is arranged in parallel so as to penetrate the stem 54 and the stem 54, and the piezoelectric vibrating reed 4 is mounted on one end side with the stem 54 interposed therebetween (mechanically joined and electrically connected). The inner lead 55a is connected to the outside, and the other end is electrically connected to the outside. The two lead terminals 55 are electrically connected to the outside, and the stem 54 and the lead terminal 55 are fixed by being filled inside the stem 54. And an insulating filler 56 to be used.
The stem 54 is formed in a ring shape with a metal material. The material of the filler 56 is, for example, borosilicate glass. Further, a plating layer of the same material is applied to the surface of the lead terminal 55 and the outer periphery of the stem 54, respectively.

In the two lead terminals 55, a portion protruding into the case 53 serves as an inner lead 55a, and a portion protruding outside the case 53 serves as an outer lead 55b. The lead terminal 55 has a diameter of about 0.12 mm, for example, and Kovar (FeNiCo alloy) is commonly used as a base material of the lead terminal 55. The outer surface of the lead terminal 55 is covered with a plating layer 57 (see FIG. 5). As a plating material to be coated, copper (Cu) plating or the like is used for the base film, and solder plating is used for the finishing film.
Further, the outer periphery of the stem 54 is similarly plated, and the inside of the case 53 is in a vacuum state by being cold-welded in the vacuum to the inner periphery of the case 53 while interposing the plating on the outer periphery of the stem 54. Can be hermetically sealed.

  As shown in FIG. 5, the inner lead 55a and the mount electrodes 16 and 17 are mounted on the finishing layer 84b via a solder joint K formed by melting the plating layer 57. That is, the inner lead 55a and the mount electrodes 16 and 17 are mechanically joined to each other via the solder joint K and are electrically connected at the same time. As a result, the piezoelectric vibrating piece 4 is mounted on the two lead terminals 55.

  The two lead terminals 55 described above function as external connection terminals that are electrically connected to the outside on the outer lead 55 b side and mounted on the piezoelectric vibrating reed 4 on the inner lead 55 a side.

  When the piezoelectric vibrator 51 configured as described above is operated, a predetermined drive voltage is applied to the outer leads 55 b of the two lead terminals 55. As a result, a current is allowed to flow to the excitation electrode 15 including the first excitation electrode 13 and the second excitation electrode 14 via the inner lead 55a, the joint K, the mount electrodes 16 and 17, and the extraction electrodes 19 and 20. The pair of vibrating arm portions 10 and 11 can be vibrated at a predetermined frequency in a direction in which the pair of vibrating arm portions 10 and 11 approaches and separates. 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, the manufacturing process of the piezoelectric vibrating reed 4 described above will be described below with reference to a flowchart.
FIG. 6 is a flowchart of the manufacturing process of the piezoelectric vibrating piece 4.
As shown in FIG. 6, the manufacturing process of the piezoelectric vibrating reed 4 includes an outer shape forming process S110, an electrode forming process S120, and a passivation film forming process (corresponding to “insulating film forming process” in the claims) S130. The frequency adjustment step S140 and the fragmentation step S150 are provided. Details of each step will be described below.

(Outline forming process)
FIG. 7 is an explanatory diagram of the outer shape forming step S110.
First, as shown in FIG. 7, a piezoelectric plate 4a having the outer shape of the piezoelectric vibrating piece 4 (see FIG. 1) on a quartz wafer W, and a recess (see FIG. 1) that becomes a groove 18 (see FIG. 1) on the piezoelectric plate 4a. An outer shape forming step S110 for forming (not shown) is performed. In the outer shape forming step S110, first, polishing is completed, and a wafer W finished to a predetermined thickness with high accuracy is prepared. Subsequently, the wafer W is etched by a photolithography technique to form a piezoelectric plate 4 a formed in the outer shape of the piezoelectric vibrating reed 4 on the wafer W and a concave portion that becomes the subsequent groove portion 18. The piezoelectric plate 4a is connected to the etched wafer W by a connecting portion 4b. Thus, the outer shape forming step S110 is completed.

(Electrode formation process)
FIG. 8 is a cross-sectional view taken along the line CC of FIG. 7 in the electrode forming step S120.
Next, an electrode forming step S120 for forming the electrodes of the excitation electrodes 13 and 14, the extraction electrodes 19 and 20 and the mount electrodes 16 and 17 (all of which are shown in FIG. 1) on the surface of the wafer W on which the piezoelectric plate 4a is formed. I do.

  As shown in FIG. 8, in the electrode forming step S120, a metal material is applied from the first surface F and the second surface S of the wafer W by a sputtering method, a vacuum evaporation method, or the like, and then a metal film 84 to be each electrode later. Is deposited. The metal film 84 is formed by laminating a base layer 84a and a finishing layer 84b. In the present embodiment, chromium having a good adhesion to the crystal is formed as the base layer 84a. On the surface of the base layer 84a, gold having good wettability with respect to solder or the like is formed as a finishing layer 84b.

  Subsequently, a photoresist film 85 is formed on the metal film 84, and the photoresist film 85 is exposed and developed to form a mask pattern (not shown). Subsequently, the electrode metal film is etched through the mask pattern to form the electrode patterns of the excitation electrodes 13 and 14, the extraction electrodes 19 and 20 and the mount electrodes 16 and 17 (see FIG. 1).

Finally, the finishing layer 84b in the formation region of the excitation electrodes 13 and 14 and the extraction electrodes 19 and 20 is peeled off. Thus, the excitation electrodes 13 and 14 and the extraction electrodes 19 and 20 are formed only by the chromium underlayer 84a. Thereby, the adhesion between the excitation electrodes 13 and 14 and the extraction electrodes 19 and 20 and the passivation film 24 can be enhanced.
The mount electrodes 16 and 17 are formed of a chromium underlayer 84a and a gold finish layer 84b. When the excitation electrodes 13 and 14, the extraction electrodes 19 and 20 and the mount electrodes 16 and 17 are formed, the electrode formation step S120 is completed.

(Passivation film formation process)
Next, a passivation film forming step S130 for forming a passivation film 24 (see FIG. 1) covering the excitation electrodes 13 and 14 and the extraction electrodes 19 and 20 is performed. The passivation film forming step S130 includes a wafer attaching step S131, a rotating film forming step S133, and a front / back reversing step S137. In the passivation film forming step S130, the passivation film 24 is formed on the plurality of wafers W by the sputtering method using the sputtering apparatus 70 (see FIG. 9). Below, after explaining sputtering apparatus 70 first, each process of passivation film formation process S130 is explained in full detail.

(Sputtering equipment)
FIG. 9 is an external perspective view of the sputtering apparatus 70.
FIG. 10 is a plan view of the rotating drum 71.
In FIG. 9, the film forming chamber 90 is schematically illustrated by a two-dot chain line. In the following description, the rotation direction of the rotary drum 71 is the θ direction, the positive rotation side is the + θ side, and the opposite side is the −θ side. The direction along the rotation axis P of the rotating drum 71 is the H direction, the upper side in FIG. 9 is the + H side, and the lower side is the −H side.

  As shown in FIG. 9, the sputtering apparatus 70 mainly includes a film formation chamber 90, targets 77 (two targets 77 in this embodiment) provided in the film formation chamber 90, a rotating drum 71, and a wafer. The fixing jig 80 is used.

The film forming chamber 90 is provided with a gas introduction pipe 91 for introducing a reaction gas and a gas discharge pipe 92 communicating with a suction pump (not shown).
A gas for generating plasma such as argon gas is introduced into the film forming chamber 90 from the gas introduction pipe 91. The air outlet 91 a of the gas introduction pipe 91 is disposed in the vicinity of a target 77 described later, so that ionized plasma generation gas can reliably collide with the target 77. In the present embodiment, two gas introduction pipes 91 are provided in accordance with the number of targets 77. From the gas introduction pipe 91, argon gas is introduced into the film forming chamber 90 at a gas flow rate of, for example, about 27 sccm.

  The gas discharge pipe 92 is connected to a suction pump (not shown). By operating the suction pump to suck the plasma generating gas G in the film forming chamber 90, the inside of the film forming chamber 90 is maintained at a predetermined film forming pressure. In the present embodiment, the film forming pressure is maintained at 0.4 Pa, for example.

(target)
The target 77 is formed of SiO ₂ which is a raw material for the passivation film 24 (see FIG. 1). Two targets 77 are arranged on both sides of the rotating drum 71. The main surface 77a of the target 77 has a larger area than a plurality of flat surfaces 71a (hereinafter simply referred to as “outer peripheral surface 71a”) that constitute the peripheral surface of the prismatic rotary drum 71. Thereby, when the rotary drum 71 rotates, the plurality of wafers W attached to the outer peripheral surface 71 a of the rotary drum 71 can pass through the target 77. Therefore, the passivation film 24 can be formed on the plurality of wafers W.

(Rotating drum)
The rotary drum 71 is a prismatic member whose cross-sectional shape perpendicular to the rotation axis P is a substantially regular decagon. The rotating drum 71 has a rotating shaft P installed in the vertical direction, and is driven around a rotating shaft P by being driven by a drive motor (not shown).

On the outer peripheral surface 71a of the rotating drum 71, there is provided a mounting bracket 73 capable of attaching a wafer fixing jig 80 described later to the outer peripheral surface 71a of the rotating drum 71.
As shown in FIG. 9, the mounting bracket 73 is formed in a substantially U shape when viewed from the normal direction of the outer peripheral surface 71 a of the rotating drum 71. The mounting bracket 73 includes a pair of side portions 74 extending substantially in parallel along the H direction on the + θ side and the −θ side of the outer peripheral surface 71 a of the rotating drum 71, and the −H side end portions of the pair of side portions 74. And a bottom 75 connecting the two.

As shown in FIG. 10, the side portion 74 has a substantially L-shaped cross section perpendicular to the rotation axis P, and a presser portion 74 a formed substantially parallel to the outer peripheral surface 71 a of the rotary drum 71. And a restricting portion 74b formed substantially perpendicular to the outer peripheral surface 71a of the rotating drum 71.
The distance between the pressing portion 74 a and the outer peripheral surface 71 a of the rotary drum 71 is slightly larger than the thickness of the wafer fixing jig 80. Further, the separation distance between the pair of restricting portions 74 b arranged on the + θ side and the −θ side on the outer peripheral surface 71 a of the rotating drum 71 is formed slightly wider than the width in the θ direction of the wafer fixing jig 80.
The + H side of the mounting bracket 73 is open, and the wafer fixing jig 80 is inserted into the region surrounded by the pair of side portions 74, the bottom 75 of the mounting bracket 73 and the outer peripheral surface 71a of the rotating drum 71 from the opening on the + H side. By inserting, the wafer fixing jig 80 is attached to the rotating drum 71.

The holding portion 74a of the side portion 74 prevents the wafer fixing jig 80 from moving out in the radial direction and dropping off when the rotary drum 71 is rotating with the wafer fixing jig 80 attached. Yes. The restricting portion 74b of the side portion 74 restricts the wafer fixing jig 80 from moving in the θ direction when the rotating drum 71 is rotating with the wafer fixing jig 80 attached.
The bottom portion 75 is in contact with the −H side end of the wafer fixing jig 80 to prevent the wafer fixing jig 80 from falling off to the −H side.
Since the + H side of the mounting bracket 73 is open, the wafer fixing jig 80 can be easily attached to and detached from the rotating drum 71. Therefore, the front / back reversing step S137 described later can be easily performed.

(Wafer fixing jig)
FIG. 11 is a front view of the wafer fixing jig 80.
12 is a cross-sectional view taken along the line DD of FIG.
As shown in FIG. 11, the wafer fixing jig 80 is a flat plate-like member having the H direction as the longitudinal direction and the θ direction as the width direction. As shown in FIG. 12, the wafer fixing jig 80 is formed by superposing a first holding plate 81 and a second holding plate 83.
The first holding plate 81 has an opening 81 a that exposes the first surface F of the wafer W. In the present embodiment, the opening 81 a is formed in a substantially square shape corresponding to the film forming range of the first surface F of the wafer W. The opening 81a is formed to be slightly smaller than the outer shape of the wafer W.

  A recess 82 having a depth in the thickness direction of the first holding plate 81 is formed on the contact surface 81 b of the first holding plate 81 with the second holding plate 83. The recess 82 is formed by cutting out the corner of the opening 81a on the second holding plate 83 side over the entire circumference. The depth of the recess 82 is substantially the same as or slightly deeper than the thickness of the wafer W. The outer shape of the recess 82 is substantially the same as or slightly larger than the outer shape of the wafer W. As a result, while the first surface F of the wafer W is exposed from the opening 81a, the contact surface 81b and the second surface S of the wafer W are substantially flush with each other in the recess 82 of the first holding plate 81. The wafer W can be placed on the substrate.

  The second holding plate 83 has an opening 83 a that exposes the second surface S of the wafer W at a position facing the opening 81 a of the first holding plate 81. Similarly to the opening 81 a of the first holding plate 81, the opening 83 a of the second holding plate 83 is formed in a substantially square shape corresponding to the film formation range of the second surface S of the wafer W. It is formed slightly smaller than the outer shape.

  The openings 81a and 83a and the recess 82 are formed in three locations at a predetermined interval in line with the wafer fixing jig 80 in the H direction. Therefore, three wafers W can be set on the wafer fixing jig 80. The wafer W is disposed in the recess 82, and the second holding plate 83 is brought into contact with the contact surface 81 b of the first holding plate 81, whereby the wafer W is held by the first holding plate 81 and the second holding plate 83. it can.

(Wafer mounting process)
In the passivation film forming step S130, a wafer attaching step S131 is first performed. In the wafer attaching step S131, after attaching the plurality of wafers W to the wafer fixing jig 80, the plurality of wafers W are mounted on the rotating drum together with the wafer fixing jig 80.

In the wafer attaching step S131, first, the wafer W is set on the wafer fixing jig 80.
Specifically, as shown in FIG. 12, the wafer W is placed in the recess 82 of the first holding plate 81, and the second holding plate 83 is brought into contact with the contact surface 81 b of the first holding plate 81 to overlap. By matching, the wafer W is disposed between the first holding plate 81 and the second holding plate 83. The first holding plate 81 and the second holding plate 83 are fixed by a clip (not shown) provided on the first holding plate 81, thereby holding the wafer W between the first holding plate 81 and the second holding plate 83. doing.

  In this embodiment, when the wafer W is set on the wafer fixing jig 80, a metal mask (not shown) having an opening corresponding to the film formation region of the passivation film 24 is used as the first surface F and the second surface of the wafer W. It is arranged on the surface S. Specifically, a metal mask is arranged between the first surface F of the wafer W and the first holding plate 81 and between the second surface S and the second holding plate 83, and the first holding plate 81 and the first holding plate 81 are arranged. The two holding plates 83 hold the wafer W together with the metal mask.

  Further, the wafer W is set on the wafer fixing jig 80 so that the vibrating arm portions 10 and 11 (see FIG. 1) formed on the wafer W are along the + H direction. In other words, the wafer W is arranged so that the outer side surfaces 10a and 11a and the inner side surfaces 10b and 11b (see FIG. 1) of the vibrating arm portions 10 and 11 face the θ direction. Thus, in the rotation film forming step S133 described later, the outer surfaces 10a and 11a and the inner surfaces 10b and 11b of the vibrating arm portions 10 and 11 are placed before and after the wafer W faces the target 77 during the rotation of the rotating drum 71. It can be made to face the target 77.

FIG. 13 is an explanatory diagram of the wafer attachment step S131.
Subsequently, as shown in FIG. 13, a wafer fixing jig 80 is inserted between the mounting bracket 73 and the outer peripheral surface 71 a of the rotating drum 71, and a plurality of wafers W are put on the rotating drum 71 together with the wafer fixing jig 80. Install. Specifically, the outer peripheral surface 71a of the rotating drum 71 and one of the first holding plate 81 and the second holding plate 83 (the second holding plate 83 in this embodiment) are opposed to each other. Then, the wafer fixing jig 80 is inserted from the + H side of the rotating drum 71 between the outer peripheral surface 71a of the rotating drum 71 and the pressing portion 74a of the mounting bracket 73, and the wafer fixing jig 80 is attached to the rotating drum 71. Yes.
In this embodiment, the wafer W together with the wafer fixing jig 80 is attached to all ten outer peripheral surfaces 71 a formed on the rotary drum 71. Since three wafers W are attached to the wafer fixing jig 80, a total of 30 wafers W are attached to the rotating drum 71.

(Rotating film forming process)
FIG. 14 is an explanatory diagram of the rotational film forming step S133. In FIG. 14, the wafer fixing jig 80 is not shown for easy understanding. Further, the size of the vibrating arm portions 10 and 11 of the piezoelectric plate 4a (see FIG. 7) formed on the wafer W is exaggerated.
Next, as shown in FIG. 14, a rotating film forming step S <b> 133 is performed in which the rotating drum 71 is rotated to form the passivation film 24.

In the rotating film forming step S133, the rotating drum 71 is rotated in the θ direction while ejecting plasma generating gas to the target 77 and ejecting SiO ₂ from the target 77. Then, when the wafer W passes through the position facing the target 77 a plurality of times, SiO ₂ ejected from the target 77 is deposited on the wafer W, and the passivation film 24 is formed.
In this embodiment, the rotation speed of the rotating drum 71 is set to 10 rpm, for example, and film formation is performed while rotating the rotating drum 71 for 20 minutes. In addition, as described above, two targets 77 are arranged on both sides of the rotating drum 71. Therefore, the passivation film 24 is formed by passing the wafer W through the position facing the target 77 400 times.

In the rotational film forming step S133, the outer surfaces 10a and 11a and the inner surfaces of the vibrating arms 10 and 11 formed on the piezoelectric plate 4a before and after the wafer W faces the target 77 during the rotation of the rotating drum 71. 10 b and 11 b (see FIG. 1) face the target 77.
Specifically, as shown in FIG. 14, when the wafer W is at a position M1 on the −θ side with respect to the target 77 when viewed from the H direction, the inner side surface 10b of the vibrating arm portion 10 and the outer side of the vibrating arm portion 11 are removed. The side surface 11 a faces the target 77. Thereby, the passivation film 24 is formed mainly on the outer side surface 11a and the inner side surface 10b of the vibrating arm portions 10 and 11.
Further, when the wafer W is at a position M2 on the + θ side with respect to the target 77 as viewed from the H direction, the outer side surface 10a and the inner side surface 11b of the vibrating arm portions 10 and 11 face the target 77. Thus, the passivation film 24 is formed mainly on the outer side surface 10a and the inner side surface 11b of the vibrating arm portions 10 and 11.
As described above, the passivation film 24 is formed on the outer side surfaces 10a and 11a and the inner side surfaces 10b and 11b of the vibrating arm portions 10 and 11, so that the passivation film 24 can be surely formed even on the narrow portion 25 (see FIG. 3). Is deposited. Therefore, it is possible to reliably prevent a short circuit between the pair of excitation electrodes 13 and 14.

FIG. 15 is a cross-sectional view of the mount electrodes 16 and 17 (see FIG. 1) during the rotating film forming process.
By the way, the mount electrodes 16 and 17 formed on the piezoelectric plate 4a are formed by laminating the chromium underlayer 84a and the gold finishing layer 84b as described above. Here, when the mount electrodes 16 and 17 are heated to a high temperature in the rotational film forming step S133, so-called metal diffusion may occur in which the metals melt between the underlayer 84a and the finishing layer 84b. As the metal diffusion proceeds, the chromium of the underlayer 84a is deposited on the surface of the finishing layer 84b, and the wettability of the finishing layer 84b to solder or the like may be deteriorated.

  However, as described above, in the rotational film forming step S133, the passivation film 24 is formed in a plurality of times (400 times in the present embodiment), so that the passivation film 24 is formed at a time as compared with the case where the passivation film 24 is formed at a time. The time for each time the wafer W faces the target 77 is shortened. For this reason, the temperature of the wafer W when the passivation film 24 is formed is suppressed to 100 ° C. or lower, which is significantly lower than the temperature of the wafer W (about 200 ° C. to 400 ° C.) during the conventional film formation. Accordingly, as shown in FIG. 15, metal diffusion between the chromium underlayer 84a and the gold finish layer 84b in the mount electrodes 16 and 17 is suppressed, so that chromium of the underlayer 84a is deposited on the surface of the finish layer 84b. Can be prevented. Thereby, the good wettability of the finishing layer 84b can be maintained.

(Deposition surface confirmation S135 and front / back reversing step S137)
As shown in FIG. 6, after the passivation film 24 is formed on the first surface F of the wafer W, the passivation film 24 is not formed on the second surface S of the wafer W (when the determination is NO in S135). ), The rotational film forming step S133 is performed again on the second surface S of the wafer W. At this time, the front and back reversing step S137 for reversing the front and back of the first surface F and the second surface S of the wafer W and attaching the wafer W to the rotating drum 71 is performed, and then the rotational film forming step S133 is performed again. When the passivation film 24 is formed on the second surface S of the wafer W (when the determination is YES in S135), the process proceeds to the next frequency adjustment step S140.

In the front / back reversing step S137, the wafer W set on the rotating drum 71 is extracted to the + H side of the rotating drum 71 together with the wafer fixing jig 80, and the entire wafer W is removed from the rotating drum 71 together with the wafer fixing jig 80. Subsequently, the wafer fixing jig 80 and the wafer W are turned over. Finally, similarly to the wafer attaching step S131, the wafer fixing jig 80 is inserted between the mounting bracket 73 and the outer peripheral surface 71a of the rotating drum 71 again from the + H side of the rotating drum 71, and a plurality of pieces are attached to the rotating drum 71. The wafer W is attached together with the wafer fixing jig 80 (see FIG. 13).
In this way, by reversing the front and back of the plurality of wafers W together with the wafer fixing jig 80, the passivation film is formed on the first surface F and the second surface S of the wafer W without removing the wafer W from the wafer fixing jig 80. 24 can be formed. In addition, the front and back of the plurality of wafers W can be easily reversed at a time. Therefore, since the passivation film 24 can be efficiently formed on the first surface F and the second surface S of the plurality of wafers W, the number of steps of the passivation film forming step S130 can be reduced.

(Frequency adjustment process)
Next, a frequency adjustment step S140 for roughly adjusting the resonance frequency is performed on all the vibrating arm portions 10 and 11 (see FIG. 1) formed on the wafer W. The frequency adjustment step S140 is performed by irradiating the coarse adjustment films 21a and 21b of the weight metal film 21 with laser light to partially evaporate and changing the weight. The fine adjustment for adjusting the resonance frequency with higher accuracy is performed in the state of the piezoelectric vibrator 1 (see FIG. 16). Above, frequency adjustment process S140 is complete | finished.

(Smallization process)
Finally, the connecting portion 4b (see FIG. 7) that connects the wafer W and the piezoelectric plate 4a is cut, and a fragmentation step S150 is performed to separate the plurality of piezoelectric vibrating pieces 4 from the wafer W into pieces. Thereby, a plurality of tuning fork type piezoelectric vibrating reeds 4 can be manufactured from one wafer W at a time. At this time, the manufacturing process of the piezoelectric vibrating reed 4 is completed, and a plurality of piezoelectric vibrating reeds 4 can be obtained.

(Manufacturing process of cylinder type piezoelectric vibrator)
Next, a manufacturing method of the cylinder type piezoelectric vibrator 51 (see FIG. 4) including the piezoelectric vibrating piece 4 manufactured as described above will be described.
In the manufacturing process of the cylinder type piezoelectric vibrator 51, first, an airtight terminal manufacturing process for manufacturing the plug 52 shown in FIG. 4 is performed. Subsequently, a plating process is performed in which the same material is coated on the outer surface of the lead terminal 55 of the plug 52 and the outer periphery of the stem 54 by a wet plating method.

Subsequently, a mounting process for joining the mount electrodes 16 and 17 of the piezoelectric vibrating reed 4 to the inner lead 55a is performed. Specifically, while heating the inner lead 55a, the inner lead 55a and the piezoelectric vibrating piece 4 are overlapped with a predetermined pressure. As a result, the solder plating that forms the plating layer 57 (see FIG. 5) of the inner lead 55a is dissolved and spreads quickly on the finishing layer 84b. Thereby, the inner lead 55a and the mount electrodes 16 and 17 can be connected. As a result, the piezoelectric vibrating piece 4 can be mounted. That is, the piezoelectric vibrating reed 4 is mechanically supported by the lead terminals 55 and is electrically connected.
In addition, when connecting the inner lead 55a and the mount electrodes 16 and 17, it mounted by performing heating and pressurization, However, You may connect using an ultrasonic wave.

  Subsequently, in order to eliminate the distortion caused by the mount described above, after performing baking at a predetermined temperature, the frequency adjustment (fine adjustment) of the piezoelectric vibrating reed 4 is performed. Specifically, the frequency adjustment is performed by evaporating the fine-tuning film 21b of the weight metal film 21 with a laser while measuring the frequency while the entire piezoelectric vibrator 51 is placed in the vacuum chamber.

Subsequently, a case press-fitting process is performed in which the case 53 is press-fitted into the stem 54 so as to accommodate the mounted piezoelectric vibrating reed 4 therein, and the piezoelectric vibrating reed 4 is hermetically sealed. Specifically, the case 53 is press-fitted into the outer periphery of the stem 54 of the plug 52 while applying a predetermined load in a vacuum. Then, since the plating metal film formed on the outer periphery of the stem 54 is elastically deformed, it can be hermetically sealed by cold welding. Thereby, the piezoelectric vibrating reed 4 can be sealed and vacuum-sealed in the case 53.
Finally, after the case 53 is fixed, screening, electrical property inspection, and appearance inspection are performed to finally check the electrical performance, dimensions, quality, and the like. Thus, the cylinder package type piezoelectric vibrator 51 shown in FIG. 4 can be manufactured.

(effect)
According to the present embodiment, in the rotational film forming step S133, the film formation of the passivation film 24 is divided into a plurality of times by passing the position where the wafer W faces the target 77 a plurality of times (in this embodiment, 400 times). Can be done. Thereby, since the time per time the wafer W faces the target 77 can be shortened, an increase in the temperature of the wafer W during the formation of the passivation film 24 can be suppressed. In addition, since the temperature of the wafer W decreases after the wafer W passes the position facing the target 77 and before the wafer W passes the position facing the target 77 again, the temperature increase of the wafer W is suppressed. it can. Therefore, metal diffusion of the mount electrodes 16 and 17 can be prevented.
In the rotational film forming step S133, the outer surfaces 10a and 11a and the inner surfaces of the vibrating arms 10 and 11 formed on the piezoelectric plate 4a before and after the wafer W faces the target 77 during the rotation of the rotating drum 71. 10 b and 11 b can be made to face the target 77. Therefore, in addition to the first surface F and the second surface S of the piezoelectric plate 4a, the passivation film 24 can be reliably formed on the outer surfaces 10a and 11a and the inner surfaces 10b and 11b of the vibrating arm portions 10 and 11. In particular, the passivation film 24 can be reliably formed also on the portion 25 formed at the connection portion between the vibrating arm portions 10 and 11 and the base portion 12. Thereby, a short circuit of a pair of excitation electrodes 13 and 14 can be prevented reliably.

  Further, according to the present embodiment, the piezoelectric vibrating reed 4 is manufactured by a manufacturing method capable of preventing metal diffusion of the mount electrodes 16 and 17, so that the chromium of the base layer 84 a is formed on the finish layer 84 b of the mount electrodes 16 and 17. Does not precipitate (see FIG. 15). Therefore, the wettability of the mount electrodes 16 and 17 is maintained well, so that the piezoelectric vibrator 1 in which the mounting strength of the piezoelectric vibrating reed 4 is ensured can be obtained.

(Surface mount type piezoelectric vibrator)
Next, a surface-mount type piezoelectric vibrator provided with the piezoelectric vibrating piece 4 manufactured by the manufacturing method described above will be described.
FIG. 16 is an external perspective view of the surface-mount type piezoelectric vibrator 1.
FIG. 17 is an internal configuration diagram of the surface-mount type piezoelectric vibrator 1 and is a plan view in a state where the lid substrate 3 is removed.
18 is a cross-sectional view taken along line EE in FIG.
FIG. 19 is an exploded perspective view of the piezoelectric vibrator 1 shown in FIG.
In the following description, the bonding surface of the base substrate 2 to the lid substrate 3 is the upper surface U, and the outer surface of the base substrate 2 is the lower surface L. In FIG. 19, the excitation electrodes 13 and 14, the extraction electrodes 19 and 20, the mount electrodes 16 and 17, the weight metal film 21, and the passivation film 24 are omitted for easy understanding of the drawing.

  As shown in FIG. 16, the piezoelectric vibrator 1 of this embodiment includes a package 9 in which a base substrate 2 and a lid substrate 3 are anodically bonded via a bonding film 35, and a cavity 3a of the package 9 as shown in FIG. 1 is a surface-mounting type piezoelectric vibrator 1 including a piezoelectric vibrating piece 4 housed in the housing.

  As shown in FIG. 18, the base substrate 2 and the lid substrate 3 are anodic bondable substrates made of a glass material, for example, soda-lime glass, and are formed in a substantially plate shape. A cavity 3 a for accommodating the piezoelectric vibrating reed 4 is formed on the side of the lid substrate 3 that is bonded to the base substrate 2.

  A bonding film 35 for anodic bonding is formed on the entire surface of the lid substrate 3 on the bonding surface side with the base substrate 2. The bonding film 35 of this embodiment is formed of a silicon film, and the bonding film 35 and the base substrate 2 are anodically bonded, and the cavity 3a is vacuum-sealed. Note that the bonding film 35 may be formed of aluminum.

  The piezoelectric vibrator 1 includes through electrodes 32 and 33 that penetrate the base substrate 2 in the thickness direction and conduct the inside of the cavity 3 a and the outside of the piezoelectric vibrator 1. The through electrodes 32 and 33 are disposed in the through holes 30 and 31 that penetrate the base substrate 2. The through holes 30 and 31 are formed so as to be accommodated in the cavity 3a when the piezoelectric vibrator 1 is formed.

  The through-electrodes 32 and 33 play a role of bringing the lead-out electrodes 36 and 37, which will be described later, and the external electrodes 38 and 39 into conduction. The through electrodes 32 and 33 are formed, for example, by inserting the metal pin 7 into the through holes 30 and 31, filling a glass frit between the through holes 30 and 31 and the metal pin 7, and firing it. Thus, since the metal pins 7 and the glass frit can completely close the through holes 30 and 31, airtightness in the cavity 3a can be maintained.

  As shown in FIG. 19, a pair of lead-out electrodes 36 and 37 are patterned on the upper surface U side of the base substrate 2. Further, bumps B made of gold, solder, or the like are formed on the pair of lead-out electrodes 36 and 37, respectively, and the pair of mount electrodes of the piezoelectric vibrating piece 4 is mounted using the bumps B. Thereby, one mount electrode 17 (see FIG. 17) of the piezoelectric vibrating reed 4 is electrically connected to one through electrode 32 through one lead-out electrode 36, and the other mount electrode 16 (see FIG. 17) is connected to the other. The other through electrode 33 is electrically connected to the other through electrode 37.

  A pair of external electrodes 38 and 39 are formed on the lower surface L of the base substrate 2. The pair of external electrodes 38 and 39 are formed at both ends in the longitudinal direction of the base substrate 2, and are electrically connected to the pair of through electrodes 32 and 33, respectively.

  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 voltage can be applied to the first excitation electrode 13 and the second excitation electrode 14 of the piezoelectric vibrating piece 4, so that the pair of vibrating arm portions 10 and 11 are vibrated at a predetermined frequency so as to approach and separate from each other. be able to. The vibration of the pair of vibrating arm portions 10 and 11 can be used as a time source, a timing source for control signals, a reference signal source, and the like.

(Oscillator)
Next, an embodiment of an oscillator according to the present invention will be described with reference to FIG.
As shown in FIG. 20, the oscillator 110 according to the present embodiment is configured by configuring the piezoelectric vibrator 1 as an oscillator electrically connected to the integrated circuit 111. The oscillator 110 includes a substrate 113 on which an electronic element component 112 such as a capacitor is mounted. An integrated circuit 111 for an oscillator is mounted on the substrate 113, and the piezoelectric vibrator 1 is mounted in the vicinity of the integrated circuit 111. The electronic element component 112, the integrated circuit 111, 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 110 configured as described above, when a voltage is applied to the piezoelectric vibrator 1, the piezoelectric vibrating piece in the piezoelectric vibrator 1 vibrates. This vibration is converted into an electric signal by the piezoelectric characteristics of the piezoelectric vibrating piece and input to the integrated circuit 111 as an electric signal. The input electrical signal is subjected to various processes by the integrated circuit 111 and output as a frequency signal. Thereby, the piezoelectric vibrator 1 functions as an oscillator.
In addition, by selectively setting the configuration of the integrated circuit 111, for example, an RTC (real-time clock) module or the like as required, the operation date and time of the device or external device in addition to a single-function oscillator for a clock, etc. Functions such as controlling time and providing time and calendar can be added.

  According to this embodiment, since the piezoelectric vibrator 1 in which the mounting strength of the piezoelectric vibrating reed 4 is ensured is provided, the highly reliable oscillator 110 can be provided.

(Electronics)
Next, an embodiment of an electronic apparatus according to the invention will be described with reference to FIG. Note that a portable information device 120 having the above-described piezoelectric vibrator 1 will be described as an example of the electronic device.
First, the portable information device 120 of this embodiment is represented by, for example, a mobile phone, and is a development and improvement of a wrist watch in the prior 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 120 of this embodiment will be described. As shown in FIG. 21, the portable information device 120 includes the piezoelectric vibrator 1 and a power supply unit 121 for supplying power. The power supply unit 121 is made of, for example, a lithium secondary battery. The power supply unit 121 includes a control unit 122 that performs various controls, a clock unit 123 that counts time, a communication unit 124 that communicates with the outside, a display unit 125 that displays various information, and the like. A voltage detection unit 126 that detects the voltage of the functional unit is connected in parallel. Power is supplied to each functional unit by the power supply unit 121.

  The control unit 122 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 122 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 for the CPU.

  The timer unit 123 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 vibrates, and the vibration is converted into an electric signal by the piezoelectric characteristics of the crystal, and is input to the oscillation circuit as an electric signal. The output of the oscillation circuit is binarized and counted by a register circuit and a counter circuit. Then, signals are transmitted to and received from the control unit 122 through the interface circuit, and the current time, current date, calendar information, and the like are displayed on the display unit 125.

The communication unit 124 has functions similar to those of a conventional mobile phone, and includes a radio unit 127, a voice processing unit 128, a switching unit 129, an amplification unit 130, a voice input / output unit 131, a telephone number input unit 132, a ring tone generation unit. 133 and a call control memory unit 134.
The radio unit 127 exchanges various data such as audio data with the base station via the antenna 135. The audio processing unit 128 encodes and decodes the audio signal input from the radio unit 127 or the amplification unit 130. The amplifying unit 130 amplifies the signal input from the audio processing unit 128 or the audio input / output unit 131 to a predetermined level. The voice input / output unit 131 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 133 generates a ring tone in response to a call from the base station. The switching unit 129 switches the amplifying unit 130 connected to the voice processing unit 128 to the ringing tone generating unit 133 only when an incoming call is received, so that the ringing tone generated by the ringing tone generating unit 133 passes through the amplifying unit 130. To the audio input / output unit 131.
Note that the call control memory unit 134 stores a program related to incoming / outgoing call control of communication. The telephone number input unit 132 includes, for example, number keys from 0 to 9 and other keys. By pressing these number keys and the like, a telephone number of a call destination is input.

  The voltage detection unit 126 detects the voltage drop and notifies the control unit 122 when the voltage applied to each functional unit such as the control unit 122 by the power supply unit 121 falls below a predetermined value. . The predetermined voltage value at this time is a value set in advance as a minimum voltage necessary to stably operate the communication unit 124, and is, for example, about 3V. Upon receiving the voltage drop notification from the voltage detection unit 126, the control unit 122 prohibits the operations of the radio unit 127, the voice processing unit 128, the switching unit 129, and the ring tone generation unit 133. In particular, it is essential to stop the operation of the wireless unit 127 with high power consumption. Further, the display unit 125 displays that the communication unit 124 has become unusable due to insufficient battery power.

That is, the operation of the communication unit 124 can be prohibited by the voltage detection unit 126 and the control unit 122, and that effect can be displayed on the display unit 125. 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 125.
In addition, the function of the communication part 124 can be stopped more reliably by providing the power cutoff part 136 that can selectively cut off the power supply of the part related to the function of the communication part 124.

  According to the present embodiment, since the piezoelectric vibrator 1 in which the mounting strength of the piezoelectric vibrating reed 4 is ensured is provided, a highly reliable portable information device 120 can be provided.

(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. 22, the radio-controlled timepiece 140 according to the present embodiment includes the piezoelectric vibrator 1 electrically connected to the filter unit 141, 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 both the property of propagating the ground surface and the property of propagating while reflecting the ionosphere and the ground surface, so the propagation range is wide, and the above two transmitting stations cover all of Japan. doing.

Hereinafter, the functional configuration of the radio timepiece 140 will be described in detail.
The antenna 142 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 143 and filtered and tuned by the filter unit 141 having the plurality of piezoelectric vibrators 1.
The piezoelectric vibrator 1 according to this embodiment includes crystal vibrator portions 148 and 149 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 144.
Subsequently, the time code is taken out via the waveform shaping circuit 145 and counted by the CPU 146. The CPU 146 reads information such as the current year, accumulated date, day of the week, and time. The read information is reflected in the RTC 147, and accurate time information is displayed.
Since the carrier wave is 40 kHz or 60 kHz, the crystal vibrator portions 148 and 149 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. Therefore, when the radio timepiece 140 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 present embodiment, since the piezoelectric vibrator 1 in which the mounting strength of the piezoelectric vibrating reed 4 is ensured is provided, the highly reliable radio timepiece 140 can be provided.

  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.

  In the manufacturing method of the piezoelectric vibrating piece 4 of the present embodiment, the tuning fork type piezoelectric vibrating piece 4 is manufactured. However, the piezoelectric vibrating piece 4 manufactured by the manufacturing method of the present invention is not limited to the tuning fork type. A cut-type piezoelectric vibrating piece (thickness sliding vibrating piece) may be used. Moreover, you may manufacture electronic components other than a piezoelectric vibrating piece with the manufacturing method of this invention.

  In this embodiment, the wafer W is attached to the rotary drum 71 using the wafer fixing jig 80, but the wafer W may be directly attached to the rotary drum 71. However, the present embodiment is advantageous in that a plurality of wafers W can be easily attached and detached at a time.

  In this embodiment, the mount electrodes 16 and 17 are formed of two metal films 84 of a chromium underlayer 84a and a gold finish layer 84b. However, the materials of the underlayer 84a and the finish layer 84b are the same as those in the embodiment. Not limited to. Further, the number of layers of the mount electrodes 16 and 17 is not limited to two, and may be three, for example.

  In the present embodiment, as the film forming conditions for forming the passivation film 24 with the sputtering apparatus 70, the film forming pressure is 0.4 Pa, the rotating speed of the rotating drum 71 is 10 rpm, and the flow rate of the plasma generating gas is 27 sccm. The number of targets 77 was 2, and the film formation time was 20 minutes per side. However, the film forming conditions of the sputtering apparatus 70 are not limited to this.

In this embodiment, SiO ₂ which is a raw material of the passivation film 24 (see FIG. 1) is used for the target 77, argon gas is used for the plasma generation gas, and the SiO ₂ passivation film 24 is formed on the wafer W. Was. However, for example, the passivation film 24 of SiO ₂ may be formed on the wafer W by using silicon (Si) for the target 77 and using a mixed gas of argon gas and carbon dioxide for the plasma generating gas.

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric vibrator 4 ... Piezoelectric vibrating piece 4a ... Piezoelectric plate 13, 14 ... Excitation electrode 16, 17 ... Mount electrode 24 ... Passivation film (insulating film) 70 ... Sputtering device 71 ... Rotating drum 71a ... Outer peripheral surface 77 ... Target 84 ... Metal film 84b ... Finish layer 80 ... Wafer fixing jig 81a, 83a ... Opening 110 ... -Oscillator 120 ... Portable information device (electronic device) 140 ... Radio clock W ... Wafer F ... First surface P ... Rotating axis S ... Second surface S130 ... Passivation film Film forming process (insulating film forming process) S131: Wafer mounting process S133: Rotating film forming process

Claims (11)

A method of manufacturing a piezoelectric vibrating piece, comprising: a piezoelectric plate formed from a wafer; an excitation electrode that vibrates the piezoelectric plate; and a mount electrode that is electrically connected to the excitation electrode and is formed by laminating a metal film. There,
An insulating film forming step of forming, by sputtering, an insulating film covering at least the excitation electrode with respect to at least one of the first surface and the second surface of the wafer;
The insulating film forming step includes
Using a sputtering apparatus equipped with a target as a raw material of the insulating film and a rotating drum rotatable around a rotation axis;
The insulating film forming step includes
A wafer attaching step of attaching the wafer to the outer peripheral surface of the rotating drum;
A rotating film forming step of rotating the rotating drum to form the insulating film so that the wafer passes through a position facing the target;
With
In the rotating film forming step, the insulating film is formed by rotating the rotating drum so that the wafer passes a position facing the target a plurality of times. A method of manufacturing a piezoelectric vibrating piece according to claim 1,
The method of manufacturing a piezoelectric vibrating piece according to claim 1, wherein the mount electrode includes a finishing layer mainly composed of gold as an outermost layer of the stacked metal films. A method of manufacturing a piezoelectric vibrating piece according to claim 1 or 2,
The sputtering apparatus includes a wafer fixing jig to which a plurality of the wafers can be attached.
In the wafer attaching step, a plurality of the wafers are attached to the wafer fixing jig, and the plurality of wafers are attached to the rotating drum together with the wafer fixing jig. A method of manufacturing a piezoelectric vibrating piece according to claim 3,
The wafer fixing jig has an opening that exposes the first surface and the second surface of the wafer,
In the insulating film forming step, after the rotating film forming step is performed, the first surface and the second surface of the plurality of wafers are reversed together with the wafer fixing jig, and the rotating film forming process is performed again. A method of manufacturing a piezoelectric vibrating piece, comprising performing a step. A method for manufacturing a piezoelectric vibrating piece according to any one of claims 1 to 4,
The method of manufacturing a piezoelectric vibrating piece, wherein the temperature of the wafer in the insulating film forming step is 100 ° C. or lower. A piezoelectric vibrating piece manufacturing apparatus comprising: a piezoelectric plate formed from a wafer; an excitation electrode that vibrates the piezoelectric plate; and a mount electrode that is electrically connected to the excitation electrode and is formed by laminating a metal film. There,
A sputtering apparatus for forming an insulating film covering at least the excitation electrode by a sputtering method on at least one of the first surface and the second surface of the wafer;
The sputtering apparatus includes:
A target as a raw material of the insulating film;
A rotating drum rotatable around a rotation axis;
With
The wafer is attached to an outer peripheral surface of the rotating drum, and is formed so as to pass a position facing the target a plurality of times when the rotating drum rotates. apparatus. The piezoelectric vibrating piece manufacturing apparatus according to claim 6,
In a state where a plurality of the wafers are attached, a wafer fixing jig attached to the outer peripheral surface of the rotating drum is provided,
The apparatus for manufacturing a piezoelectric vibrating piece, wherein the wafer fixing jig has an opening that exposes the first surface and the second surface of the wafer.   A piezoelectric vibrator comprising the piezoelectric vibrating piece manufactured by the manufacturing method according to claim 1.   An oscillator, wherein the piezoelectric vibrator according to claim 8 is electrically connected to an integrated circuit as an oscillator.   9. An electronic apparatus, wherein the piezoelectric vibrator according to claim 8 is electrically connected to a time measuring unit. A radio-controlled timepiece, wherein the piezoelectric vibrator according to claim 8 is electrically connected to a filter portion.

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