JP2004297342A - Piezoelectric oscillating piece, piezoelectric device and manufacturing method of them, as well as cell phone unit using piezoelectric device and electric apparatus using piezoelectric device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric oscillating piece capable of preparing an appropriate separation construction for an electrode without forming an extremely weak part structurally at a base, in manufacturing the piezoelectric oscillating piece. <P>SOLUTION: The piezoelectric oscillating piece is entirely formed with quartz crystal, and provided with a base 51 and a plurality of oscillating arms 34 and 35 extended from the base in parallel. The manufacturing method includes an outer shape etching process for forming the outer shape by etching a substrate, and a groove forming process for forming grooves 56 and 57 at the oscillating arms by half etching. The groove forming process includes a process for forming a thin width groove 65 with its bottom at a crotch between the plurality of oscillating arms at the same time with half etching, a process for forming a metal film for an electrode all over the surface, and a process for coating by injecting resist at an angle crossing the front surface and the rear face of the substrate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a piezoelectric vibrating reed and a method of manufacturing the same, a piezoelectric device containing the piezoelectric vibrating reed in a package, and a mobile phone and an electronic device using the piezoelectric device.
[0002]
[Prior art]
In a small information device such as a hard disk drive (HDD), a mobile computer, or an IC card, or a mobile communication device such as a mobile phone, a car phone, or a paging system, a crystal in which a piezoelectric vibrating piece is housed in a package. Piezoelectric devices such as vibrators and crystal oscillators are widely used.
FIG. 12 is a schematic plan view showing a known configuration example of a piezoelectric vibrating reed used in such a piezoelectric device.
[0003]
In FIG. 12A, a piezoelectric vibrating reed 1 is formed of, for example, a single crystal of quartz, and has a main vibrating portion 2 that oscillates longitudinally and a width provided at a position where the main vibrating portion 2 has the smallest displacement. In this structure, connecting portions 3 and 3 provided in the directions and support portions 4 and 4 provided in parallel with the main vibrating portion 2 from both ends of the connecting portions 3 and 3 are provided in parallel and connected by a base 5.
[0004]
Excitation electrodes 6 and 7 having mutually different polarities are formed on both sides of the main vibration section 2, and the excitation electrodes 6 and 7 are respectively connected to the connection sections 3 and 3 and the support sections 4 and 4. It is routed and electrically isolated from one another at the base 5.
Thus, by applying a drive voltage to each of the excitation electrodes 6 and 7 from the outside, an electric field is formed inside the quartz material, and the main vibrating portion 2 vibrates. By extracting a vibration frequency based on such vibration, it is used for various signals such as a control clock signal.
[0005]
Here, the piezoelectric vibrating reed 1 having such a structure is formed in a very small size, and the excitation electrodes 6 and 7 provided on the surface thereof are formed not only on the front surface and the back surface but also on the inner side surface. It is formed.
In this case, the electrode films serving as the excitation electrodes 6 and 7 are first formed on the entire surface including the side surfaces of the piezoelectric vibrating reed 1, and then separated into the excitation electrode 6 and the excitation electrode 7 at the base 5. . For this reason, it is not so difficult to separate the electrodes formed on the front surface and the back surface by photolithography using light irradiated to these surfaces almost perpendicularly, but the inner side surface which is hardly exposed is also difficult. It must be completely separated, and such processing is difficult.
[0006]
Therefore, in the piezoelectric vibrating reed 1 shown in FIG. 12A, a concave portion is formed inside the base portion 5 and, as shown in FIG. In the case of etching, the fin portion 9 as an inclined surface formed by the etching anisotropy of the quartz material is used to enable exposure in the vertical direction and separate the electrode inside the concave portion 8.
The outer end 5a of the base 5 is cut off from the crystal wafer after the electrode is formed, so that no electrode is formed on the outer surface of the outer end 5a. Thus, since the electrode film can be completely removed from the front and back surfaces of the base 5, the area of the recess 8 and the outer end 5a of the base 5, the excitation electrodes 6 and 7 can be completely separated.
[0007]
[Patent Document 1] JP-A-59-104813
[0008]
[Problems to be solved by the invention]
However, in the piezoelectric vibrating reed 1 of FIG. 12, in order to completely expose the inner side surface of the base 5, it is necessary to actively use the fins by utilizing the etching anisotropy of the quartz, so that the quartz etching time is reduced. By shortening and exposing this area, the side electrodes were divided.
However, when the concave portion 8 is formed inside the base portion 5, the structure becomes weak, stress is concentrated at this portion, and there is a disadvantage that the piezoelectric vibrating reed 1 is easily damaged.
Further, as in the conventional case, if the fin is left in order to actively use the fin, the vibration characteristics of the piezoelectric vibrating reed are affected. In particular, when the piezoelectric vibrating reed is formed in a small size, if the fin is left as described above, there is a problem that the CI (crystal impedance) value of the piezoelectric vibrating reed increases. Therefore, a technique of dividing (separating) electrodes without using fins has been required.
[0009]
The present invention relates to a piezoelectric vibrating reed in which a piezoelectric vibrating reed can be appropriately provided with an electrode separating structure without forming an extremely weak portion in a base in manufacturing a piezoelectric vibrating reed, a method of manufacturing the same, and a piezoelectric vibrating reed. It is an object to provide a piezoelectric device using a resonator element, and a mobile phone and an electronic device using the piezoelectric device.
[0010]
[Means for Solving the Problems]
According to a first aspect of the present invention, a piezoelectric vibrating reed comprising a base and a plurality of vibrating arms extending in parallel from the base, and each vibrating arm having a groove extending in the length direction is made of a piezoelectric material. Forming an outer shape by etching the substrate, and a groove forming step of forming the groove by half-etching. Simultaneously with the half-etching, a step of forming a narrow groove with a bottom at a crotch between the plurality of vibrating arms, a step of forming a metal film to be an electrode over the entire surface, At a crossing angle, a step of spraying and applying a resist, and further, in the step of spraying and applying the resist, the resist is hardly adhered. It was to remove the serial metal film, the manufacturing method of the piezoelectric vibrating piece is achieved.
[0011]
According to the configuration of the first invention, the present invention is applied to a method of manufacturing a piezoelectric vibrating reed including a base and a plurality of vibrating arms extending from the base. In the plurality of vibrating arms, a groove extending in the length direction and a narrow bottomed groove extending in the length direction of the vibrating arm are formed in a crotch portion between the plurality of vibrating arms. is there. In the forming step, after the step of etching the substrate made of the piezoelectric material to form the outer shape, a narrow bottomed groove is formed simultaneously with the half etching of the groove formed in the vibrating arm. Then, after forming a metal film to be an electrode on the entire surface, in the step of applying a resist for forming the shape of the electrode film, the resist is sprayed at an angle crossing the front and back surfaces of the substrate. Thereby, since the resist hardly adheres in the narrow bottomed groove, the metal film formed in the narrow bottomed groove is also removed when the metal film is removed. Will be. Thereby, in the crotch portions of the plurality of vibrating arms, in the region where the narrow bottomed groove is formed, the metal films formed on the inner side surfaces of the respective vibrating arms are appropriately separated and insulated. Become. Since such a narrow groove with a bottom is formed by using the conventional half-etching step of the groove of the vibrating arm, it is not necessary to increase the number of steps, and it is necessary to take extra manufacturing time. And can be made without.
Further, the narrow bottomed groove not only exerts the function of separating the electrodes as described above, but also has a structure in which the bottom is left by being configured as a bottomed groove. The narrow groove does not completely divide the piezoelectric material on both sides of the groove. For this reason, the structure of the base portion is made strong, and the stress is not concentrated and damaged as compared with the conventional case in which the concave portion is formed in the crotch portion.
As a result, as an effect of the present invention, in manufacturing a piezoelectric vibrating reed, it is possible to appropriately provide an electrode separation structure without forming an extremely structurally weak portion in the base.
[0012]
A second invention is characterized in that, in the configuration of the first invention, patterning of the groove formed in the vibrating arm and patterning of the narrow bottomed groove are performed simultaneously prior to the outer shape etching.
According to the configuration of the second invention, prior to etching for forming the outer shape, the patterning of the groove formed in the vibrating arm and the patterning of the narrow bottomed groove are simultaneously performed. At the time of the half etching for forming the groove of the vibrating arm, the groove having the narrow bottom can be simultaneously half etched.
[0013]
According to a third aspect of the present invention, in the configuration of the first or second aspect, the inside of the narrow bottomed groove of the crotch portion is formed to have a slightly inclined surface except for the bottom portion. It is characterized by doing.
According to the configuration of the third invention, when the narrow bottomed groove of the crotch portion is formed based on the etching anisotropy of the piezoelectric material, the inside of the groove except for the bottom portion, The slightly inclined surface makes the structure joined by the bottom more robust.
[0014]
Further, according to a fourth aspect of the present invention, there is provided a piezoelectric device including a base formed entirely of a piezoelectric material, a base, and a plurality of vibrating arms extending in parallel from the base. A piezoelectric vibrating reed having at least excitation electrodes respectively formed in the grooves of the respective vibrating arms and on respective side surfaces of the respective vibrating arms, and at a crotch between the respective vibrating arms. The excitation electrodes provided on the respective inner side surfaces of the respective vibrating arms are achieved by the piezoelectric vibrating reeds which are electrically separated by the provided narrow bottomed grooves.
According to the configuration of the fourth invention, since the crotch portion between the plurality of vibrating arms is provided with a narrow bottomed groove, the excitation electrodes provided on each inner side surface of each of the vibrating arms are connected. Can be appropriately separated. The narrow bottomed groove not only exerts the function of separating the electrodes as described above, but also is configured as a bottomed groove, so that the crotch portion is formed as compared with a conventional through hole. Therefore, stress is not concentrated and the base is not damaged, and the structure of the base is strong. In other words, since the excitation electrode having a fine line width is precisely formed, a durable piezoelectric vibrating reed that is not easily damaged even with a small size without damaging the vibration performance can be obtained.
[0015]
According to a fifth aspect of the present invention, there is provided a piezoelectric device including a piezoelectric vibrating reed in a package, wherein the piezoelectric vibrating reed is entirely formed of a piezoelectric material, and is parallel to the base. A plurality of vibrating arms extending in a direction, a piezoelectric vibrating reed having a groove extending in the length direction in each vibrating arm, at least in the groove of each vibrating arm, and each side surface of each vibrating arm Each of the vibrating arms has an excitation electrode, and the excitation electrodes provided on each inner side surface of each of the vibrating arms are electrically connected by a narrow bottomed groove provided at the crotch between the vibrating arms. This is achieved by piezoelectric devices that are physically separated.
According to the configuration of the fifth aspect, the piezoelectric vibrating reed housed in the package has a narrow bottomed groove at the crotch between the plurality of vibrating arms. The excitation electrodes provided on the inner side surfaces can be appropriately separated from each other. Since the narrow groove having the bottom has a structure in which the bottom is left, the narrow groove does not completely divide the piezoelectric material on both sides of the groove at the crotch portion. The structure is strong and will not be damaged. For this reason, since the excitation electrode having a fine line width is precisely formed, the vibration performance is not impaired even if it is made small, and it is hard to be damaged, so that a highly reliable piezoelectric device can be obtained.
[0016]
According to a sixth aspect of the present invention, there is provided a piezoelectric vibrating reed having a base and a plurality of vibrating arms extending in parallel from the base, and each of the vibrating arms having a groove extending in a length direction is provided in the package. A manufacturing method of the piezoelectric device, wherein the manufacturing process of the piezoelectric vibrating reed includes an outer shape etching process for forming an outer shape by etching the substrate, and a groove forming process of forming the groove by half etching. In the step, simultaneously with the half etching of the groove, a step of forming a narrow groove with a bottom at the crotch between the plurality of vibrating arms, and a step of forming a metal film to be an electrode on the entire surface, A step of spraying and applying a resist at an angle intersecting with the front and back surfaces of the substrate, and further, in the step of spraying and applying the resist, the resist is hardly adhered. The fine exposed the metal film is removed in the groove, after joining the piezoelectric vibrating piece after completed package, the method of manufacturing a piezoelectric device so as to seal the package is achieved.
According to the configuration of the sixth aspect of the present invention, as described in the operation of the first aspect of the present invention, the number of manufacturing steps of the piezoelectric device is not increased, and the required process time and equipment are hardly changed. Since the excitation electrodes are difficult to form and have a fine line width precisely formed, a piezoelectric vibrating reed that does not impair the vibration performance even in a small size can be provided in the package.
[0017]
Further, according to a seventh aspect of the present invention, there is provided a mobile phone device using a piezoelectric device in which a piezoelectric vibrating reed is housed in a package, wherein the piezoelectric vibrating reed is entirely formed of a piezoelectric material. And a plurality of vibrating arms extending in parallel from the base, wherein each vibrating arm has a groove extending in the longitudinal direction, at least in the groove of each vibrating arm, and Excitation electrodes formed on each side of the arm are provided on each inner side of each vibrating arm by a narrow bottomed groove provided at the crotch between the vibrating arms. This is achieved by a portable telephone device in which excitation electrodes are obtained by a piezoelectric device that is electrically separated from each other to obtain a control clock signal.
[0018]
Still further, according to an eighth aspect of the present invention, there is provided an electronic apparatus using a piezoelectric device in which a piezoelectric vibrating piece is housed in a package, wherein the piezoelectric vibrating piece is entirely formed of a piezoelectric material, And a plurality of vibrating arms extending in parallel from the base, wherein each vibrating arm has a groove extending in the longitudinal direction, at least in the groove of each vibrating arm, and Excitation electrodes formed on each side of the arm are provided on each inner side of each vibrating arm by a narrow bottomed groove provided at the crotch between the vibrating arms. The present invention is achieved by an electronic device in which excitation electrodes are obtained by a piezoelectric device which is electrically separated to obtain a control clock signal.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
1 and 2 show an embodiment of the piezoelectric device of the present invention. FIG. 1 is a schematic plan view thereof, and FIG. 2 is a schematic sectional view taken along line BB of FIG.
In the drawing, the piezoelectric device 30 shows an example in which a quartz oscillator is formed, and the piezoelectric device 30 accommodates a piezoelectric vibrating piece 32 in a package 36. The package 36 is formed, for example, by laminating a plurality of substrates formed by molding ceramic green sheets of aluminum oxide as an insulating material, and then sintering. Each of the plurality of substrates is formed with a predetermined hole inside thereof so that when stacked, a predetermined internal space S2 is formed inside when stacked.
This internal space S2 is a housing space for housing the piezoelectric vibrating reed.
That is, as shown in FIG. 2, in this embodiment, the package 36 is formed by, for example, stacking a first laminated substrate 61, a second laminated substrate 64, and a third laminated substrate 68 from below. ing.
[0020]
In the drawing of the inner space S2 of the package 36 near the left end in the drawing, the second laminated substrate 64 exposed to the inner space S2 and constituting the inner bottom portion has, for example, an electrode formed by nickel plating and gold plating on tungsten metallization. Parts 31, 31 are provided.
The electrode portions 31 are connected to the outside and supply a drive voltage. A conductive adhesive 43, 43 is applied on each of the electrode portions 31, 31, and a base 51 of the piezoelectric vibrating reed 32 is placed on the conductive adhesive 43, 43, and the conductive adhesive 43 , 43 are cured. In addition, as the conductive adhesives 43, 43, those obtained by adding conductive particles such as silver fine particles to a synthetic resin agent as an adhesive component exhibiting a bonding force can be used. Or polyimide-based conductive adhesive or the like can be used.
[0021]
The piezoelectric vibrating reed 32 is formed by, for example, etching quartz as a piezoelectric material by a manufacturing process described later. In the case of the present embodiment, the piezoelectric vibrating reed 32 is formed in a small size to obtain required performance. For this reason, the shape is particularly shown in the schematic perspective view of FIG.
That is, the piezoelectric vibrating reed 32 includes a base 51 fixed to the package 36 side, and a pair of vibrating arms 34 and 35 that are bifurcated and extend in parallel with the base 51 as a base end toward the left in the figure. A so-called tuning-fork type piezoelectric vibrating reed, which has a shape like a tuning fork as a whole, is used.
[0022]
On each of the vibrating arms 34 and 35 of the piezoelectric vibrating reed 32, long bottomed grooves 56 and 57 extending in the length direction are formed. The grooves 56 and 57 are formed on the front and back surfaces of the vibrating arms 34 and 35, respectively, as shown in FIG. 4, which is a sectional view taken along the line CC in FIG.
Further, in FIG. 3, extraction electrodes 52 and 53 are formed near both ends in the width direction of the end (the right end in FIG. 3) of the base 51 of the piezoelectric vibrating reed 32. The extraction electrodes 52 and 53 are similarly formed on the back surface (not shown) of the base 51 of the piezoelectric vibrating piece 32.
[0023]
These lead-out electrodes 52 and 53 are portions connected to the package-side electrode portions 31 and 31 shown in FIG. 1 by the conductive adhesives 43 and 43 as described above. As shown, the extraction electrodes 52 and 53 are connected to excitation electrodes 54 and 55 provided in grooves 56 and 57 of the vibrating arms 34 and 35, respectively. Further, as shown in FIG. 4, the excitation electrodes 54 and 55 are also formed on both side surfaces of the vibrating arms 34 and 35. For example, for the vibrating arm 34, the excitation electrodes 54 and 55 in the groove 57 are provided. And the excitation electrodes 55 on the side surfaces thereof have different polarities from each other. Further, regarding the vibrating arm 35, the excitation electrode 55 in the groove 56 and the excitation electrode 54 on the side surface thereof have different polarities from each other.
[0024]
As can be understood with reference to FIGS. 3 and 4, the side surface electrode portions 54a and 55a formed on the inner side surfaces of the vibrating arms 34 and 35 facing each other have different polarities from each other. It is separated at a narrow groove 65 formed in the crotch between the arm 34 and the vibrating arm 35. FIG. 5 is an enlarged view of the narrow groove 65, and FIG. 6 is a diagram schematically illustrating the narrow groove 65 of FIG.
The structure of the narrow groove 65 will be described with reference to these.
[0025]
As shown in FIG. 5, the narrow groove 65 is a bottomed groove extending in the Y direction, which is the length direction of the vibrating arms 34 and 35. The narrow groove 65 is formed in the same shape on both the front and back surfaces of the base 51. As shown in FIG. 6, the three walls 68, 68, 68 of the narrow groove 65 are inclined surfaces such that the bottom 67 has a smaller area than the opening. The shape of the inside of the narrow groove 65 is closer to the actual shape in FIG. 5 than in FIG.
The narrow groove 65 has a groove width W1 extremely smaller than the length D1.
It is preferable that the groove width W1 of the narrow groove 65 is formed, for example, to be about 0.01 mm to 0.03 mm. If the groove width W1 is too large, the side surface electrode portions 54a and 55a cannot be appropriately separated due to the process described later. Also, when the groove width W1 is too small, the electrodes come close to each other and the electrodes cannot be separated.
[0026]
Further, the narrow groove 65 not only separates the side surface electrode portions 54a and 55a, but also includes the bottom portion 67, thereby coupling the piezoelectric materials on both sides of the narrow groove 65 forming the base portion 51. As described above, the structure of the base portion 51 is much stronger than the structure in which the concave portion is formed in this portion. This effectively prevents stress from being applied to the crotch portion 66 of the base portion 51 and causing breakage.
[0027]
Further, as shown in FIG. 2, through holes 37a and 37b continuous with the two laminated substrates constituting the package 36 are formed near the center of the bottom surface of the package 36 so that the through holes opened to the outside. 37 are provided. Out of the two through-holes constituting the through-hole 37, the outer through-hole 37a, which is the second hole, has a larger inner diameter than the first hole 37b opened inside the package. I have. Thereby, the through-hole 37 is a stepped opening including the downward stepped portion 62 in FIG. 2. It is preferable that a metal coating portion is provided on the surface of the step portion 62.
[0028]
Here, as the metal sealing material 38 filled in the through hole 37, for example, a sealing material containing no lead is preferably selected. For example, silver brazing, Au / Sn alloy, Au / Ge alloy And so on. Correspondingly, it is preferable to form nickel plating and gold plating on the tungsten metallization on the metal coating on the surface of the step 62.
A lid 39 is joined to the open upper end of the package 36 to seal it. The lid body 39 is preferably sealed and fixed to the package 36, and then, as shown in FIG. In order to adjust the frequency, it is made of a material that transmits light, in particular, a thin glass plate.
As a glass material suitable for the lid 39, for example, borosilicate glass is used as a thin glass manufactured by a down-draw method.
Further, in FIG. 2, a concave portion 42 is provided by removing a part of the inside of the second substrate 64. Thus, when an external impact is applied to the piezoelectric device 30, even if the tip of the piezoelectric vibrating piece 32 is displaced in the direction of arrow D, the tip of the piezoelectric vibrating piece 32 collides with the inner bottom of the package 36. Damage is effectively prevented.
[0029]
Next, FIGS. 7 to 10 are process diagrams for explaining an example of a method of manufacturing the piezoelectric vibrating reed 32 of the present embodiment. Each process in FIG. 7 is a cut end view of a portion corresponding to FIG. Areas corresponding to the cut surfaces of the vibrating arms 34 and 35 indicated by are shown in the order of steps. Also, in FIGS. 7F to 10, a region corresponding to the cut end surface along the line DD in FIG. 5 is shown on the right side of the region corresponding to the cut surface of the vibrating arms 34 and 35, and further, FIG. After that, a schematic diagram of the region shown in FIG. 5 is shown at the right end in the order of steps.
An example of a method of manufacturing the piezoelectric vibrating piece 32 and an example of a method of manufacturing the piezoelectric device 30 will be described with reference to these drawings.
[0030]
In FIG. 7A, a substrate 71 made of a piezoelectric material having a size capable of separating a plurality or a large number of the piezoelectric vibrating reeds 32 is prepared. At this time, when the substrate 71 is turned into a tuning fork type piezoelectric vibrating piece 32 by the progress of the process, the piezoelectric axis is set so that the X axis shown in FIG. 3 is the electric axis, the Y axis is the mechanical axis, and the Z axis is the optical axis. It will be cut out of a material, for example a single crystal of quartz. In addition, when cutting from a single crystal of quartz, in the above-described orthogonal coordinate system including the X axis, the Y axis, and the Z axis, the XY plane including the X axis and the Y axis is rotated around the X axis by about minus 5 degrees clockwise. It is formed to be inclined by plus or minus 5 degrees.
[0031]
(Corrosion resistant film forming process)
As shown in FIG. 7A, a corrosion-resistant film 72 is formed on the front surface (front and back surfaces) of the substrate 71 by a technique such as sputtering or vapor deposition. As shown in the figure, a corrosion-resistant film 72 is formed on both front and back surfaces of a substrate 71 made of quartz, and the corrosion-resistant film 72 is composed of, for example, a chromium layer as a base layer and a gold coating layer coated thereon. You.
In the following steps, the same processing is performed on the upper and lower surfaces of the substrate 71, so that only the upper surface will be described to avoid complexity.
[0032]
(Outline patterning process)
Next, as shown in FIG. 7B, a resist 73 is applied to the entire front and back surfaces of the substrate 71 (resist coating step). Then, a resist 73 is applied for external patterning. As the resist 73, for example, an ECA-based or PGMEA-based positive resist can be suitably used.
[0033]
(Outline forming etching process)
Then, as shown in FIG. 7C, a mask 74 (not shown) having a predetermined pattern width is arranged for external patterning, and after exposure, the exposed resist 73 is removed. Correspondingly, the corrosion resistant film 72 is also removed in the order of Au and Cr.
Next, as shown in FIG. 7D, a portion outside the outer shape of the piezoelectric vibrating piece 32 is exposed, and as shown in FIG. 7E, a resist 74 is applied to the entire surface. Then, as shown in FIG. 7 (f), not only the portion outside the outer shape of the piezoelectric vibrating reed 32 and the groove portion of each vibrating arm, but also the resist corresponding to the narrow groove as shown in the right end diagram. 74 is removed. That is, the narrow groove portion is patterned simultaneously with the groove portion of the vibrating arm.
[0034]
Then, as shown in FIG. 8 (g), the outer shape of the piezoelectric vibrating piece is etched using, for example, a hydrofluoric acid solution as an etchant with respect to the substrate 71 exposed as a portion outside the outer shape of the piezoelectric vibrating piece 32 (etching). Process). This etching process changes for 6 hours to 15 hours depending on the concentration, type, temperature and the like of the hydrofluoric acid solution. In this embodiment, the etching process is completed in about 12 hours by using hydrofluoric acid and ammonium fluoride as an etching solution, under the conditions of a volume ratio of 1: 1 and a temperature of 65 ° C. ± 1 degree (Celsius). .
That is, in the present embodiment, unlike the conventional piezoelectric vibrating reed, a long etching time is applied so that no fins are formed based on the etching anisotropy.
However, by adopting a process that does not leave such fins, the symmetry of the shape of both sides of the vibrating arm of the piezoelectric vibrating piece can be improved, the vibration characteristics can be improved, and the CI value can be kept low. .
[0035]
(Half etching process)
After the outer shape of the piezoelectric vibrating reed is formed, as shown in FIG. 8 (h), the corrosion-resistant film 72 in the groove portion and the narrow groove portion of the vibrating arm is removed.
As shown in FIG. 8 (i), the substrate 71 exposed by removing the corrosion-resistant film 72 is further half-etched using a hydrofluoric acid solution or the like in the groove portion and the narrow groove portion of the vibrating arm.
In this embodiment, hydrofluoric acid and ammonium fluoride are used as an etching solution, and the etching process is performed in about 30 minutes to 60 minutes under the conditions of a volume ratio of 1: 1 and a temperature of 65 ° C. ± 1 degree (Celsius). Is completed.
Thus, the grooves 56 and 57 of the vibrating arm are formed, and at the same time, the narrow groove 65 having the bottom 67 is also formed.
That is, here, a half-etching process for forming the grooves 56 and 57 of the vibrating arm, which is a part of the manufacturing process for forming the piezoelectric vibrating reed of the conventional piezoelectric device, is used. Without changing the required process time, equipment, and the like, the narrow groove 65 having the function described with reference to FIG. 3 can be obtained.
[0036]
Next, as shown in FIG. 8I, the resist 74 is removed, and the state shown in FIG. This state is a state in which the electrodes of the piezoelectric vibrating reed 32 of FIG. 3 are not formed. Subsequently, as shown in FIG. 9 (l), a metal film 75 for forming an electrode is formed on the entire surface by a technique such as evaporation or sputtering. This metal film can be composed of a chromium layer as the same underlayer as the corrosion-resistant film, and a gold coating layer coated thereon.
[0037]
(Step of forming electrode film)
(Step of applying resist in electrode formation)
Next, as shown in FIG. 9 (m), a resist 76 is sprayed and applied at an angle intersecting the front surface and the back surface of the substrate 71 as shown by an arrow T. In this embodiment, the resist 76 is a so-called spray resist, and its spray angle is about 90 degrees with respect to the front and back surfaces of the substrate 71.
Here, the resist 76 is diluted with a highly volatile solvent so as to be compatible with the manufacturing process of the present embodiment, and has a property that the resist 76 adheres to the substrate 71 in a semi-dry state. Specifically, as a resist solution having a viscosity of about 5 cp to 40 cp, for example, an ECA-based or PGMEA-based positive resist is used, and the number of spraying is set to 2 to 4 so that the resist thickness becomes 1 μm to 3 μm. It is performed by injecting about twice.
[0038]
In this case, the injected resist 76 hardly enters the narrow groove 65. That is, the narrow groove 65 has only a very narrow groove width (see W1 in FIG. 6). Moreover, since the bottom 67 is present, the airflow forming the flow of the injected resist 76 is blocked by the bottom 67 and cannot pass through the narrow groove 65 properly. Therefore, the resist 76 hardly adheres to the wall surface 68 or the bottom surface 67 of the narrow groove 65, as shown in the right end diagram of FIG. Since the front end portion 67a of the bottom surface 67 is extremely thin (thin), the resist 76 hardly adheres, or the amount of the resist 76 is very small.
[0039]
In this manner, in the state where the resist 76 is applied as shown in FIG. 9 (m), as shown in FIG. 10 (n), a region where an electrode is to be formed (see FIG. 3) and a region where it is not. Is exposed and exposed to remove the resist 76, exposing the metal film to be removed.
Next, as shown in FIG. 10 (o), the exposed metal film is removed by wet etching using an etching solution such as potassium iodide. Thus, the metal film to be removed is entirely removed by etching. In particular, in the narrow groove 65, the resist 76 originally hardly adheres to the wall surface 68 and the bottom surface 67 thereof, and the front end portion 67a of the bottom surface 67 is the same. Therefore, the metal film in these regions is completely removed. Is done. Thereby, the side surface electrode portions 54a and 55a described with reference to FIG. 3 can be appropriately separated.
Finally, as shown in FIG. 10 (p), all unnecessary resists 76 are removed.
[0040]
Thus, the piezoelectric vibrating reed 32 having the structure described with reference to FIG. 3 is completed.
Therefore, the piezoelectric vibrating reed 32 completed as shown in FIG. 3 is joined to the inside of the package 36 using the conductive adhesive 43 as shown in FIGS. Thereafter, a lid 39 is joined to the package 36 using a brazing material (for example, low-melting glass). Further, the package 36 is heated in a vacuum to degas the inside of the package 36 through the through-hole 37, and the through-hole 37 is vacuum-sealed with the sealing material 38, thereby completing the piezoelectric device 30. it can.
[0041]
Thus, according to the present embodiment, after the step of etching the substrate 71 made of the piezoelectric material to form the outer shape of the piezoelectric vibrating piece 32, the grooves 56 and 57 formed in the vibrating arm are simultaneously narrowed at the time of half-etching. The bottomed groove 65 is formed. Then, after forming the metal film 75 serving as an electrode on the entire surface, in the step of applying a resist 76 for forming the shape of the electrode film, the resist 76 is jetted at an angle that intersects the front surface and the back surface of the substrate 71. It is like that.
[0042]
Thereby, since the resist 76 hardly adheres to the narrow bottomed groove 65 during the manufacturing process, when the metal film 75 is removed, if the metal film 75 is immersed in an etching solution, the narrow bottomed groove 65 is formed. The metal film 75 formed in the groove 65 is also removed. Thereby, in the crotch part 66 of the vibrating arms 34 and 35 of the piezoelectric vibrating reed 32 described in FIG. 3, the grooves 65 are formed on the inner side surfaces of the vibrating arms 34 and 35 in the area where the narrow bottomed groove 65 is formed. The side electrode portions 54a and 55a shown in FIG. 4 are appropriately separated and insulated. Since such a narrow bottomed groove 65 is formed by using the conventional half-etching step of the groove of the vibrating arm, it is not necessary to increase the number of steps, and it is possible to take extra production time. Can be made without need.
[0043]
Furthermore, the narrow bottomed groove 65 not only exerts the function of separating the electrodes as described above, but also includes the bottom part 67, so that the narrow width groove 65 is formed of the piezoelectric material on both sides of the groove. Not completely split. For this reason, the structure of the base portion 51 is strong, and the stress is not concentrated and the damage is not caused as compared with the conventional case in which the concave portion is formed in the crotch portion 66.
[0044]
FIG. 11 is a diagram illustrating a schematic configuration of a digital mobile phone device as an example of an electronic apparatus using the piezoelectric device according to the embodiment of the present invention.
In the figure, a microphone 308 for receiving the voice of the sender and a speaker 309 for outputting the received content as a voice output are provided. Controller (CPU) 301.
The controller 301 includes an information input / output unit 302 including an LCD as an image display unit and operation keys for inputting information in addition to modulation and demodulation of transmission / reception signals, and an information storage unit (memory) including a RAM and a ROM. Control 303 is performed. For this reason, the piezoelectric device 30 is attached to the controller 301, and its output frequency is used as a clock signal suitable for the control content by a predetermined frequency dividing circuit (not shown) or the like built in the controller 301. Has been. The piezoelectric device 30 attached to the controller 301 is not limited to the piezoelectric device 30 alone, but may be an oscillator combining the piezoelectric device 30 with a predetermined frequency dividing circuit or the like.
[0045]
The controller 301 is further connected to a temperature-compensated crystal oscillator (TCXO) 305, and the temperature-compensated crystal oscillator 305 is connected to a transmitting unit 307 and a receiving unit 306. Thus, even if the basic clock from the controller 301 fluctuates when the environmental temperature changes, it is corrected by the temperature-compensated crystal oscillator 305 and provided to the transmission unit 307 and the reception unit 306.
[0046]
As described above, by using the piezoelectric device 30 according to the above-described embodiment in an electronic device such as the digital cellular phone device 300, the piezoelectric vibrating reed 32 housed in the package is hardly damaged by vibration, and Since the manufacturing process is simplified and the manufacturing can be performed at low cost, the digital cellular phone device 300 having high quality and can be manufactured at low cost can be obtained.
[0047]
The invention is not limited to the embodiments described above. Each configuration of each embodiment can be appropriately combined or omitted, and can be combined with another configuration not shown.
In addition, the present invention provides all piezoelectric vibrating reeds and piezoelectric devices using the same, regardless of the names of crystal oscillators, crystal oscillators, gyros, angle sensors, etc., as long as the piezoelectric vibrating reed is housed in a package. Can be applied to
Further, in the above-described embodiment, a box-shaped package using ceramic is used for the package. However, the present invention is not limited to such a form, and a piezoelectric vibration equivalent to a package such as a metal cylindrical case may be used. The present invention can be applied to any package or case that accommodates a piece.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing an embodiment of a piezoelectric device of the present invention.
FIG. 2 is a schematic sectional view taken along the line BB of FIG. 1;
FIG. 3 is a schematic perspective view of a piezoelectric vibrating reed housed in a package of the piezoelectric device of FIG. 1;
FIG. 4 is a sectional view taken along the line CC of FIG. 3;
FIG. 5 is a schematic perspective view showing an area of a narrow groove formed in a crotch portion of the piezoelectric vibrating piece of FIG. 3;
FIG. 6 is a schematic perspective view schematically showing a further enlarged area of FIG. 5;
FIGS. 7A and 7B are schematic process diagrams sequentially showing the manufacturing steps of the piezoelectric vibrating reed housed in the piezoelectric device of FIG.
FIG. 8 is a schematic process diagram sequentially showing a process of manufacturing the piezoelectric vibrating reed housed in the piezoelectric device of FIG. 1;
FIG. 9 is a schematic process diagram sequentially showing a process of manufacturing the piezoelectric vibrating reed housed in the piezoelectric device of FIG. 1;
FIG. 10 is a schematic process diagram sequentially showing a process of manufacturing the piezoelectric vibrating reed housed in the piezoelectric device of FIG. 1;
FIG. 11 is a view showing a schematic configuration of a digital mobile phone device as an example of an electronic apparatus using a piezoelectric device according to an embodiment of the present invention.
FIG. 12 is a schematic plan view showing a configuration example of a conventional piezoelectric vibrating reed.
[Explanation of symbols]
Reference numeral 30 denotes a piezoelectric device, 32 denotes a piezoelectric vibrating piece, 34, 35 denotes a vibrating arm, 56, 57 denotes a groove, 65 denotes a narrow groove, and 66 denotes a crotch.

Claims (8)

A method of manufacturing a piezoelectric vibrating reed comprising a base and a plurality of vibrating arms extending in parallel from the base, and forming a piezoelectric vibrating reed having a groove extending in a longitudinal direction in each vibrating arm by etching a substrate made of a piezoelectric material. hand,
An outer shape etching step for forming an outer shape by etching the substrate,
In a groove forming step of forming the groove by half-etching, simultaneously with half-etching of the groove, a step of forming a narrow bottomed groove in a crotch between the plurality of vibrating arms,
Forming a metal film to be an electrode on the entire surface;
Jetting a resist at an angle that intersects the front and back surfaces of the substrate, and applying the resist.
Further, in the step of spraying the resist, the exposed metal film in the narrow groove to which the resist is hardly attached is removed. 2. The method of manufacturing a piezoelectric vibrating reed according to claim 1, wherein, prior to the outer shape etching, patterning of the groove formed in the vibrating arm and the groove having the narrow bottom are simultaneously performed. The piezoelectric vibration according to claim 1, wherein the inside of the narrow bottomed groove of the crotch portion is formed so as to have a slightly inclined surface except for the bottom portion. How to make pieces. A piezoelectric vibrating reed formed entirely of a piezoelectric material, including a base and a plurality of vibrating arms extending in parallel from the base, each vibrating arm having a groove extending in a length direction,
At least, in the groove of each of the vibrating arms, and having an excitation electrode respectively formed on each side surface of each of the vibrating arms,
A piezoelectric device characterized in that excitation electrodes provided on each inner side surface of each vibrating arm are electrically separated by a narrow bottomed groove provided in a crotch portion between each vibrating arm. Vibrating bar. A piezoelectric device containing a piezoelectric vibrating reed in a package,
The piezoelectric vibrating reed,
A piezoelectric vibrating reed formed entirely of a piezoelectric material, including a base and a plurality of vibrating arms extending in parallel from the base, each vibrating arm having a groove extending in a length direction,
At least, in the groove of each of the vibrating arms, and having an excitation electrode respectively formed on each side surface of each of the vibrating arms,
A piezoelectric device, wherein excitation electrodes provided on each inner side surface of each of the vibrating arms are electrically separated by a narrow bottomed groove provided in a crotch portion between the vibrating arms. device. A method of manufacturing a piezoelectric device, comprising: a base and a plurality of vibrating arms extending in parallel from the base, and bonding a piezoelectric vibrating reed having a groove extending in a length direction to each vibrating arm to a package,
In the manufacturing process of the piezoelectric vibrating reed,
An outer shape etching step for forming an outer shape by etching the substrate,
In a groove forming step of forming the groove by half-etching, simultaneously with half-etching of the groove, a step of forming a narrow bottomed groove in a crotch between the plurality of vibrating arms,
Forming a metal film to be an electrode on the entire surface;
Jetting a resist at an angle that intersects the front and back surfaces of the substrate, and applying the resist.
Further, in the step of spraying the resist, removing the exposed metal film in the narrow groove so that the resist hardly adheres,
A method for manufacturing a piezoelectric device, comprising bonding a completed piezoelectric vibrating reed in a package and then sealing the package. A mobile phone device using a piezoelectric device containing a piezoelectric vibrating reed in a package,
The piezoelectric vibrating reed,
A piezoelectric vibrating reed formed entirely of a piezoelectric material, including a base and a plurality of vibrating arms extending in parallel from the base, each vibrating arm having a groove extending in a length direction,
At least, in the groove of each of the vibrating arms, and having an excitation electrode respectively formed on each side surface of each of the vibrating arms,
Exciting electrodes provided on each inner side surface of each of the vibrating arms are controlled by a piezoelectric device in which the excitation electrodes provided on each inner side surface of each of the vibrating arms are electrically separated by a narrow bottomed groove provided in a crotch portion between the vibrating arms. A mobile phone device characterized in that a clock signal is obtained. An electronic device using a piezoelectric device containing a piezoelectric vibrating piece in a package,
The piezoelectric vibrating reed,
A piezoelectric vibrating reed formed entirely of a piezoelectric material, including a base and a plurality of vibrating arms extending in parallel from the base, each vibrating arm having a groove extending in a length direction,
At least, in the groove of each of the vibrating arms, and having an excitation electrode respectively formed on each side surface of each of the vibrating arms,
Excitation electrodes provided on each inner side surface of each vibrating arm are separated from each other by a piezoelectric device in which the excitation electrodes provided on each inner side of each vibrating arm are electrically separated by a narrow bottomed groove provided at the crotch between the vibrating arms. An electronic device characterized in that a clock signal is obtained.

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