JP2009044237A - Frequency adjustment method of piezoelectric device, and piezoelectric device and mask for frequency adjustment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the frequency adjustment method of a piezoelectric device, which does not bring about disconnections during frequency adjustment, even when employing a piezoelectric vibrating piece having a lead out electrode in a step part. <P>SOLUTION: In the frequency adjustment method, an excitation electrode of the piezoelectric vibrating piece which has the step part between a vibration part having the excitation electrode formed thereon and a peripheral edge having an input/output electrode formed thereon and has the lead out electrode which electrically connects the excitation electrode and the input/output electrode formed across the step part and has thickness shear vibration as main vibration, is etched after the piezoelectric vibrating piece is mounted on a package base. At least a portion of the excitation electrode placed more on the side of an energy confinement area which is formed elliptically in the vibration part, from a tangent defined for a portion closest to a portion to which the lead out electrode is connected, in the peripheral edge of the excitation electrode, out of a curve along the external shape of the energy confinement area is etched as an etching area. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a frequency adjustment method for a piezoelectric device, a piezoelectric device obtainable by performing the frequency adjustment method, and a mask used for frequency adjustment, and in particular, a step portion between a vibration portion and a peripheral portion. The present invention relates to a frequency adjustment method, a piezoelectric device, and a mask that are suitable for a piezoelectric device that mounts a piezoelectric vibrating piece having the above.

  In the manufacturing process of a piezoelectric device (for example, a piezoelectric vibrator) on which a piezoelectric vibrating piece is mounted, a piezoelectric vibrating piece, a package, and a lid are manufactured by batch processing, and after mounting the piezoelectric vibrating piece on the package, individual vibrations are produced. In general, frequency adjustment is performed in units of children.

  The frequency adjustment performed after the piezoelectric vibrating piece is mounted on the package includes weighting by applying sputtering to the excitation electrode, and cutting part of the electrode film by ion milling that irradiates an ion laser or the like. is there. In recent years when piezoelectric devices are becoming smaller and thinner, frequency adjustment is often performed by scraping off the electrode film described in the latter.

  However, when frequency adjustment is performed by scraping off the electrode film, a part of the extraction electrode connected to the excitation electrode is usually scraped off together with the excitation electrode. In such a case, a piezoelectric vibrating piece having a step portion between the vibrating portion and the peripheral portion, such as a mesa type or inverted mesa type piezoelectric vibrating piece, has the following problems.

In other words, the stepped portion between the vibrating portion and the peripheral portion, and the extraction electrode formed at the corner portion existing between the stepped portion and the flat portion are the electrodes formed on the vibrating portion and the peripheral portion which are flat surfaces. Its thickness is thinner than the film.
For this reason, when a part of extraction electrode is scraped off at the time of frequency adjustment, there exists a possibility of producing a disconnection.

Patent Document 1 discloses means suitable for adjusting the frequency of a piezoelectric vibrator employing a piezoelectric vibrating piece having a step between such a vibrating part and a peripheral part. The piezoelectric vibrating piece shown in Patent Document 1 is a plano inverted mesa type piezoelectric vibrating piece. In Patent Literature 1, when performing frequency adjustment of a piezoelectric vibrator employing such a piezoelectric vibrating piece, the reverse mesa portion is directed toward the bottom plate side of the package, and the excitation electrode formed on the flat surface of the piezoelectric vibrating piece is scraped off. It is disclosed that it should be.
JP 2002-246866 A

  However, the technique disclosed in Patent Document 1 is a bimesa type (mesa type having convex portions on both main surfaces: hereinafter simply referred to as a mesa type) or a bi-reverse mesa type (reverse having concave depressions on both main surfaces). It cannot be used when it is desired to adopt a piezoelectric vibrating piece of “mesa type: hereinafter simply referred to as an inverted mesa type” or when there is a limitation on the package shape.

  For this reason, in the present invention, even when a piezoelectric vibrating piece having an extraction electrode at a stepped portion such as a mesa type or an inverted mesa type is adopted, the piezoelectric device that does not cause a disconnection at the time of frequency adjustment. An object of the present invention is to provide a frequency adjustment method, a piezoelectric device, and a frequency adjustment mask.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1] A stepped portion is provided between a vibrating portion on which an excitation electrode is formed and a peripheral portion on which an input / output electrode is formed, and the excitation electrode and the input / output electrode are electrically connected across the stepped portion. A frequency adjusting method formed by etching the excitation electrode in a piezoelectric vibrating piece having thickness shear vibration as a main vibration, wherein at least the vibration part is formed in an elliptical shape. Of the curves along the outer shape of the energy confinement region, the excitation located on the energy confinement region side with respect to the tangent line defined with respect to the region closest to the region where the extraction electrode is connected in the peripheral portion of the excitation electrode An electrode is defined as an etching region, and at least the extraction electrode formed on the stepped portion is etched as a non-etching region. Frequency adjustment method of the chair.

  According to the frequency adjustment method of the piezoelectric device having such a feature, there is no possibility that the extraction electrode is etched at the time of frequency adjustment even if the piezoelectric device adopts a mesa type or a reverse mesa type piezoelectric vibrating piece. There is no risk of disconnection due to adjustment. In addition, since the energy confinement region in the vibration part is surely included in the etching region, the efficiency when adjusting the frequency is good.

[Adaptation example 2] A step portion is provided between the vibrating portion on which the excitation electrode is formed and the peripheral portion on which the input / output electrode is formed, and the excitation electrode and the input / output electrode are electrically connected across the step portion. Is a frequency adjusting method formed by etching the excitation electrode in a piezoelectric vibrating piece having a thickness shear vibration as a main vibration, wherein an extraction electrode to be connected is formed, and energy confinement formed in an elliptical shape in the vibration part Centering on the intersection of the short axis and the long axis constituting the elliptical shape of the region, the inner side of the ellipse-shaped short axis or a circle whose diameter is the length of the long axis is defined as an etching region, and at least the step A method of adjusting a frequency of a piezoelectric device, wherein the extraction electrode formed on a portion is etched as a non-etching region.

  Even in the frequency adjustment method of a piezoelectric device having such characteristics, even in the case of a piezoelectric device employing a mesa-type or inverted-mesa-type piezoelectric vibrating piece as in the first application example, the extraction electrode is used during frequency adjustment. There is no risk of etching, and there is no risk of disconnection due to frequency adjustment. In addition, since the energy region is surely included in the vibration part in the etching region, it can be said that the efficiency when adjusting the frequency is good.

[Application Example 3] The piezoelectric device frequency adjusting method according to Application Example 1 or Application Example 2, wherein ion milling is adopted as the etching, and heat generated during etching is absorbed by a mask for defining an etching region. A method for adjusting the frequency of a piezoelectric device, characterized by suppressing temperature rise in an etching atmosphere.

  By adopting such a method, it is possible to suppress an increase in the atmospheric temperature during frequency adjustment. Therefore, the frequency variation of the piezoelectric device due to the temperature drop after the frequency adjustment is completed can be suppressed.

[Application Example 4] A piezoelectric device in which a piezoelectric vibrating piece having at least a vibrating portion and a peripheral portion and a step portion formed between the vibrating portion and the peripheral portion is accommodated in a package, and the vibration The vibration is more than the thickness of the metal film formed on the portion of the excitation electrode formed on the portion where the extraction electrode connected to at least the input / output electrode formed on the peripheral portion is connected. A piezoelectric device characterized in that the film thickness of the metal film formed in the energy confinement region in the portion is reduced.

  By adjusting the frequency by the method shown in any one of the application examples 1 to 3, the piezoelectric device having the above characteristics can be manufactured. According to the piezoelectric device having such characteristics, the frequency adjustment of the piezoelectric device is realized by thinning the metal film formed in the energy confinement region, and the electrode film formed in the vicinity of the extraction electrode connecting portion is Remains thick. For this reason, in the manufactured piezoelectric device, there is no situation where disconnection has occurred in the extraction electrode, and disconnection due to thermal expansion distortion or external mechanical shock after manufacturing the piezoelectric device can be prevented.

[Adaptation Example 5] In the piezoelectric device according to Adaptation Example 4, the portion where the film thickness of the metal film is reduced is centered on the intersection of the minor axis and the major axis of the elliptical shape constituting the energy confinement region. A piezoelectric device characterized in that the length of the elliptical minor axis or the length of the major axis is inside a circle drawn as a diameter.

  Even with such a piezoelectric device, the same effect as that of the piezoelectric device described in the adaptation example 4 can be obtained.

[Application Example 6] A piezoelectric device according to Application Example 4 or Application Example 5, wherein the excitation electrode is rectangular, and the extraction electrode is connected to a corner of the excitation electrode.

  By making the excitation electrode rectangular and connecting the extraction electrode to the corner of the excitation electrode, the distance between the extraction electrode and the region thinned by etching can be increased. Therefore, the risk that the extraction electrode is thinned by etching can be reduced.

[Adaptation example 7] The piezoelectric device according to any one of adaptation examples 4 to 6, wherein the piezoelectric vibrating piece is a mesa type, a plano mesa type, a reverse mesa type, or a plano reverse mesa type piezoelectric vibration. A piezoelectric device characterized in that it is a piece.
This is because the effect described in any one of the adaptation examples 4 to 6 can be obtained with the piezoelectric vibrating piece having any form.

[Adaptation example 8] An excitation electrode mounted on a piezoelectric device package having a step portion between a vibrating portion and a peripheral portion and formed on a vibrating portion of a piezoelectric vibrating piece mainly having thickness-shear vibration. A mask used for ion milling, which is made of a metal member, centering on the intersection of a short axis and a long axis constituting an elliptical shape of an energy confinement region in which the thickness shear vibration is confined on the excitation electrode. A mask for frequency adjustment, characterized in that a circular opening having an elliptical short axis length or a long axis length as a diameter is formed by machining.

  Even when a circular mask is used for the elliptical etching target range, the frequency of the piezoelectric device can be adjusted by etching. Then, by forming the opening formed in the mask in a circular shape and machining it, the opening can be formed in a short time even when the metal member as the base material is thick. It becomes possible. Further, by increasing the thickness of the metal member constituting the mask, the mask absorbs heat generated during ion milling, and an increase in the ambient temperature during ion milling can be suppressed. Thereby, the frequency fluctuation of the piezoelectric device after completion of frequency adjustment can be reduced.

  Hereinafter, embodiments of a frequency adjustment method for a piezoelectric device of the present invention, a piezoelectric device manufactured using the frequency adjustment method, and a mask used in the frequency adjustment method will be described in detail with reference to the drawings. explain.

  First, a basic form of a piezoelectric device that is an object of implementing a frequency adjustment method for a piezoelectric device according to the present invention will be described with reference to FIG. 1A and 1B are diagrams showing a side cross-section of the piezoelectric device, and FIG. 1C is a diagram showing a plan view with the lid of FIG. 1B removed. is there.

In the following embodiments, a piezoelectric vibrator will be described as an example of the piezoelectric device 10 in order to simplify the description.
The piezoelectric device 10 according to the present embodiment has a piezoelectric vibration piece 20 and a package 50 as a basic configuration. The piezoelectric vibrating piece 20 is a plate made of a material that causes a piezoelectric phenomenon, such as quartz (SiO ₂ ), lithium tantalate (LiTaO ₃ ), lithium niobate (LiNbO ₃ ), or the like. Examples of the constituent material of the piezoelectric vibrating piece 20 include a polycrystalline material such as barium titanate (BaTiO ₃ ) and piezoelectric ceramics in addition to the single crystal material described above, and stable vibration characteristics over a wide temperature range. It is assumed that quartz is known as a material that can be obtained, and the piezoelectric vibrating piece 20 handled in the present embodiment is also made of quartz.

  The piezoelectric vibrating piece 20 made of quartz varies the vibration mode of the main vibration depending on the composition (cut angle) of the crystal structure. The piezoelectric vibrating reed 20 handled in the present embodiment uses a thickness-shear vibration as the vibration mode of the main vibration. The cut angle is a crystal piece cut at a cut angle called AT cut, BT cut, or SC cut. It is composed.

  In addition, the piezoelectric vibrating piece 20 of the present embodiment is of a type called a mesa type among AT-cut piezoelectric vibrating pieces. The piezoelectric element plate constituting the piezoelectric vibrating piece 20 includes a thick vibrating portion 24 and a thin peripheral portion 22 disposed around the vibrating portion 24, and the vibrating portions 24 on both the front and back surfaces. And a stepped portion 23 between the peripheral portion 22 and the peripheral portion 22.

  In the piezoelectric vibrating piece 20 according to the present embodiment, both the vibrating portion 24 and the peripheral portion 22 have a rectangular shape, and the vibrating portion 24 has an excitation electrode 26 having the same rectangular shape, and the peripheral portion 22 has an input / output electrode. 30 is formed. An extraction electrode 28 is formed between the excitation electrode 26 and the input / output electrode 30 to electrically connect both of them across the step portion 23.

  In the piezoelectric vibrating piece 20 having such a configuration, the energy of the thickness shear vibration which is the main vibration is concentrated in an elliptical shape as indicated by a broken line in FIG. 1C, and the region indicated by the elliptical shape is an energy confinement. This is called a region 26a.

  The package 50 includes a package base 36, a lid 32, and a seam ring 34 for joining the two. Examples of the package base 36 include a box shape as shown in FIG. 1A and a flat shape as shown in FIG. In both cases, a ceramic sheet is formed by firing or a metal sheet is formed. However, when the package base 36 is made of metal, the inner and outer terminals or wiring and the package base main body are arranged. It is necessary to insulate. The package base 36 includes at least mounting external terminals 40, internal mounting terminals 38, and wiring patterns (not shown) that electrically connect the mounting external terminals 40 and the internal mounting terminals 38.

  The lid 32 is a flat lid and is generally made of metal, glass, or ceramics. As a constituent member, it is desirable that the linear expansion coefficient is similar to the member constituting the package base 36 described above. For this reason, when the package base 36 is made of ceramic, it is common to employ Kovar for metal and soda glass for glass.

The seam ring 34 is a joining member used when joining the package base 36 and the lid 32 described above. Further, when the package base 36 has a flat plate shape, it also serves as a spacer constituting the cavity 42 for housing the piezoelectric vibrating piece 20.
In addition, what is necessary is just to use the technique of the seam welding conventionally known for joining of the package base 36 and the lid 32 using the seam ring 34.

Next, a frequency adjustment method for the piezoelectric device 10 having the above basic configuration will be described.
The frequency adjustment method for a piezoelectric device according to the present invention is characterized in that an etching range is determined using a mask having a specific shape when performing frequency adjustment for removing the excitation electrode 26 by etching. Therefore, various embodiments are produced depending on the shape of the mask. First, as a first embodiment, a case where frequency adjustment is performed using a mask 60 having an opening 62 as shown in FIGS. 2 and 3 will be described.

  The mask 60 used in this embodiment is made of a metal member and has an elliptical opening 62 as shown in FIG. This elliptical shape matches the shape of the energy confinement region 26a (see FIG. 1C) in which the vibration energy of the thickness shear vibration generated in the vibration part 24 having the excitation electrode 26 formed in a rectangular shape is confined.

  This is because, when the excitation electrode 26 is etched, the frequency change amount with respect to the mass drop amount of the excitation electrode 26 can be increased by etching the portion where the vibration energy is concentrated, and the frequency adjustment efficiency is improved.

  In addition, with respect to the rectangular excitation electrode 26, the extraction electrode 28 connected to the corner of the excitation electrode 26 is etched by setting the inside of an ellipse having a size not larger than the size inscribed in the rectangular excitation electrode 26 as an etching range. There is no risk of being lost. For this reason, there is no possibility that the extraction electrode 28 straddling the step portion 23 is etched, and disconnection due to etching can be prevented.

  Etching according to the present embodiment may be performed by dry etching, specifically, ion milling using an ion laser. That is, a part of the excitation electrode 26 is obtained by irradiating the piezoelectric vibrating piece 20 of the piezoelectric device (without the lid 32) with the mask 60 as shown in FIG. Is selectively scraped off.

Note that the dry etching as described above is preferably performed in an inert atmosphere by disposing a piezoelectric device in a vacuum chamber or the like.
By removing the excitation electrode 26 by such a method, it is possible to perform minute etching according to the frequency adjustment amount, and to realize flattening of the etching surface.

  Next, a second embodiment of the piezoelectric device frequency adjusting method of the present invention will be described in detail with reference to FIGS. In this embodiment, as shown in FIGS. 4 and 5, etching is performed using masks 60a and 60b having circular openings 62a and 62b.

  The diameters of the circular openings 62a and 62b formed in the masks 60a and 60b are such that the elliptical short side 27 or the long side 29 constituting the energy confinement region 26a in the piezoelectric vibrating piece 20 in which the rectangular excitation electrode 26 is formed. The length and its diameter shall be combined. The opening shape of the masks 60a and 60b is set to such a shape, and the center of the circle projected at the time of etching is matched with the intersection of the short side 27 and the long side 29 of the ellipse constituting the energy confinement region 26a. Includes the energy confinement region 26a, and an efficient frequency adjustment is possible.

  Further, since the corner portion of the excitation electrode 26 becomes a non-etched region according to the curvature of the circle formed in the masks 60a and 60b, there is no possibility that the extraction electrode 28 connected to the corner portion is etched. Therefore, there is no possibility of causing disconnection due to the frequency adjustment in the extraction electrode 28 straddling the step portion 23 between the vibration portion 24 and the peripheral portion 22.

  If the etching regions are circular, the openings 62a and 62b formed in the masks 60a and 60b are naturally circular. In general, the opening having a fine shape is formed by etching. However, the circular openings 62a and 62b as shown in FIGS. 4 and 5 can be machined by a drill or the like. It becomes. When the openings 62a and 62b are formed by machining, vertical drilling can be performed in a short time, so that the thickness of the metal members constituting the masks 60a and 60b can be increased.

  When the plate thickness of the metal plate material constituting the masks 60a and 60b is increased, the heat capacity of the masks 60a and 60b increases, so that the heat generated during the etching is absorbed by the masks 60a and 60b. For this reason, the temperature rise of the atmosphere inside the chamber can be suppressed (the temperature change is small), and the frequency fluctuation of the piezoelectric device 10 after the frequency adjustment can be reduced.

  Next, another embodiment of the frequency adjustment method for a piezoelectric device of the present invention will be described in detail with reference to FIG. In any of the above embodiments, when the major axis 72 of the excitation electrode 26 and the minor axis 70 in the direction orthogonal to the major axis 72 of the excitation electrode 26 are taken as a reference and the excitation electrode 26 is divided into four quadrants, In this quadrant, the shape of the opening 62 (62a, 62b) of the mask 60 (60a, 60b) is determined so that the etched regions have the same shape. However, in the present invention, it is sufficient that the frequency can be adjusted efficiently without etching the extraction electrode 28 at least during etching. Therefore, etching is performed using a mask 60c having an opening 62c as shown in FIG. You may do it.

  Specifically, in the two quadrants located on the extraction electrode 28 side with the short axis 70 of the excitation electrode 26 as the center, an opening is formed so that the inside of the curve along the shape of the energy confinement region 26a is an etching region. In the two quadrants located on the opposite side of the short axis 70, that is, on the distal end side of the piezoelectric vibrating piece 20, the opening 62c is formed by forming a rectangular opening that follows the outer shape of the excitation electrode 26. It is to form.

  If etching is performed using the mask 60 c having such an opening 62 c, at least the excitation electrode 26 related to the energy confinement region 26 a in the vibration part 24 can be etched and connected to the corner of the excitation electrode 26. Etching of the extracted extraction electrode 28 can be avoided.

  In the above-described embodiments, the etching is described so as to be axisymmetric with respect to the long axis 72 of the excitation electrode 26. However, since the purpose of the frequency adjustment method of the piezoelectric device of the present invention is to perform frequency adjustment efficiently while preventing disconnection of the extraction electrode 28 straddling the step portion 23, an opening having the following shape is formed. Etching may be performed using a mask having the same.

  That is, as shown in FIG. 7, only the quadrant to which the extraction electrode 28 is connected among the four quadrants divided by the short axis 70 and the long axis 72 with the center of the excitation electrode 26 as a reference, the shape of the energy confinement region 26 The opening 62d of the mask 60d is formed by forming a rectangular opening that conforms to the outer shape of the excitation electrode 26 in the other quadrants. It is to do.

  Note that the opening corresponding to the quadrant to which the extraction electrode 28 is connected is on a curve along the shape of the energy confinement region 26a and is located closest to the connection position of the extraction electrode 28 (the extraction electrode 28 and the energy confinement region). It may be formed so that the inner side of the tangent line determined at the position where the distance to 26a becomes Δl becomes an etching region (see FIG. 8).

  Next, features of the piezoelectric device 10 manufactured by the frequency adjusting method as described above will be described. In any of the piezoelectric devices 10 as described above, the energy confinement region 26 a is etched so as to avoid the vicinity of the connection portion of the extraction electrode 28 in the excitation electrode 26. For this reason, when the excitation electrode 26 of the piezoelectric vibrating piece 20 in the piezoelectric device 10 according to the above embodiment is enlarged, a state as shown in FIG. 9 can be seen.

  That is, the thickness of the electrode film in the energy confinement region 26a is smaller than the thickness of the electrode film in the vicinity of the extraction electrode connection portion 28a in the excitation electrode 26, and there is a step between the two.

  Next, a modified example of the form of the piezoelectric device to which the above-described piezoelectric device frequency adjusting method of the present invention can be effectively applied will be described with reference to the drawings. In all of the modifications shown below, most of the configurations are the same as those of the piezoelectric device shown in FIG. Accordingly, portions having the same function are denoted by the same reference numerals, and detailed description thereof will be omitted.

  A first modification shown in FIG. 10 is a piezoelectric device 10a that employs a planomesa type piezoelectric vibrating piece. The planomesa-type piezoelectric vibrating piece 20a refers to a piezoelectric vibrating piece in which a vibrating portion 24 is formed in a convex shape with respect to the peripheral edge portion 22 on one main surface, and a step portion 23 is provided therebetween.

  When the piezoelectric vibrating piece 20a having such a shape is adopted, it is considered that a flat surface may be disposed on the package opening side. In this case, the bottom plate of the package (the package base 36 in FIG. 10) and the convex shape are used. There is a concern about contact with the vibrating portion 24. Further, in order to avoid contact between the convex vibration part 24 and the package base 36, the package base 36 can be multi-staged and a concave part can be formed on the bottom plate. In this case, however, the number of steps for manufacturing the package is reduced. Become more. When the amount of the conductive adhesive 52 for mounting is increased without changing the package structure, a short circuit due to the flow of the conductive adhesive 52, a breakage due to a binder entering between the conductive fillers, resistance It is considered that an increase in the number of the particles tends to occur.

  Therefore, by disposing the convex vibration part 24 toward the opening side of the package, contact between the bottom plate of the package and the vibration part and an increase in the number of processes during the manufacture of the package can be avoided, and the conductive adhesive Short circuit due to the flow of 52, disconnection due to the configuration of the conductive adhesive 52, and the like can be suppressed.

  Next, a second modification of the piezoelectric device of the present invention is shown in FIG. A second modification shown in FIG. 11 is a piezoelectric device 10b that employs an inverted mesa type piezoelectric vibrating piece. The reverse mesa-type piezoelectric vibrating piece 20b has a thin portion formed between concave recesses formed on both main surfaces as a vibrating portion 24, and a peripheral portion 22 positioned around the vibrating portion 24 is thick. This means a piezoelectric vibrating piece.

  Even in the piezoelectric vibrating piece 20b having such a configuration, the extraction electrode 28 straddling the stepped portion 23 interposed between the vibrating portion 24 and the peripheral portion 22 has a thickness greater than that of the electrode film formed on the flat surface. Therefore, it is preferable to employ the frequency adjustment method as described above.

  Moreover, a piezoelectric device 10c shown in FIG. 12 can be given as a third modified example related to the piezoelectric device of the present invention. A piezoelectric device 10c shown in FIG. 12 is a piezoelectric device that employs a plano inverted mesa type piezoelectric vibrating piece. The plano inverted mesa type piezoelectric vibrating piece 20c is configured such that when the thin vibrating portion 24 is formed, a concave recess is formed only on one main surface and the other main surface is a flat surface. .

  Even in the piezoelectric vibrating piece 20c having such a configuration, when the recessed portion is mounted toward the package opening side, the stepped portion 23 is provided on the surface where etching is performed. For this reason, it is preferable to employ the frequency adjustment method as described above.

In the above embodiment, ion milling is mentioned as a kind of dry etching, but a technique such as plasma CVM may be used instead of ion milling.
In the above embodiment, the piezoelectric vibrator is described as an example of the piezoelectric device. However, as an application range of the present invention, the piezoelectric vibrating piece 20 in the package such as the piezoelectric oscillator 100 shown in FIG. Piezoelectric devices including other electronic components (IC in FIG. 13) are also included in the piezoelectric device of the present invention.

  Further, in all of the above embodiments, it is described that the excitation electrode is etched after the piezoelectric vibrating piece is accommodated in the package base. However, the frequency adjustment method for a piezoelectric device according to the present invention may be applied to a piezoelectric vibrating piece (for example, a form as shown in FIG. 14) formed on a wafer by batch processing in a step before folding. good. This is because even if the piezoelectric vibrating piece having such a form is individually etched, the effect of frequency adjustment can be obtained.

It is a figure which shows the basic composition of a piezoelectric device. It is a figure which shows the relationship between a piezoelectric device and a mask at the time of performing frequency adjustment. It is a figure which shows the basic composition of a mask, and its arrangement | positioning. It is a figure which shows the 1st example for demonstrating the frequency adjustment method using the mask which has a circular opening part. It is a figure which shows the 2nd example for demonstrating the frequency adjustment method using the mask which has a circular opening part. It is a figure for demonstrating the frequency adjustment method using the mask which has the opening part which defines the etching area | region which was asymmetrical with respect to the short axis of an excitation electrode, and was symmetrical with respect to the long axis. It is a figure for demonstrating the frequency adjustment method using the mask which has the opening part which defines the etching area | region which was asymmetrical with respect to both the short axis and the long axis of an excitation electrode. It is a figure which shows the application form of the mask shown in FIG. It is the elements on larger scale of the piezoelectric vibrating piece in the piezoelectric device which concerns on invention. It is a figure which shows the 1st modification about the piezoelectric device which can apply the frequency adjustment method which concerns on invention suitably. It is a figure which shows the 2nd modification about the piezoelectric device which can apply the frequency adjustment method which concerns on invention suitably. It is a figure which shows the 3rd modification about the piezoelectric device which can apply the frequency adjustment method which concerns on invention suitably. It is a figure which shows the example of the piezoelectric device contained in the piezoelectric device which concerns on invention. It is a figure which shows the example of a form of the piezoelectric vibration piece used as the object which implements the frequency adjustment method of the piezoelectric device which concerns on invention.

Explanation of symbols

  10 ......... Piezoelectric device, 20 ......... Piezoelectric vibrating piece, 22 ......... Peripheral part, 23 ......... Step part, 24 ......... Vibrating part, 26 ...... Excitation electrode, 26a ......... Energy confinement region . 28... Extraction electrode 30... I / O electrode 32... Lid 34... Seam ring 36 36 Package base 50 Package

Claims (8)

A drawer having a step portion between the vibration portion on which the excitation electrode is formed and the peripheral portion on which the input / output electrode is formed, and electrically connecting the excitation electrode and the input / output electrode across the step portion A method of adjusting the frequency formed by etching the excitation electrode in the piezoelectric vibrating piece in which an electrode is formed and thickness shear vibration is a main vibration,
At least a tangent line that is defined with respect to a portion that is closest to the portion to which the extraction electrode is connected in the peripheral portion of the excitation electrode among the curves along the outer shape of the energy confinement region formed in an elliptical shape in the vibration portion. In addition, the excitation electrode located on the energy confinement region side is defined as an etching region, and at least the extraction electrode formed on the stepped portion is etched as a non-etching region, and the frequency adjustment method of the piezoelectric device is characterized by . A drawer having a step portion between the vibration portion on which the excitation electrode is formed and the peripheral portion on which the input / output electrode is formed, and electrically connecting the excitation electrode and the input / output electrode across the step portion A method of adjusting the frequency formed by etching the excitation electrode in the piezoelectric vibrating piece in which an electrode is formed and thickness shear vibration is a main vibration,
A circle whose diameter is the length of the short axis or the length of the long axis of the elliptical shape, centered on the intersection of the short axis and the long axis constituting the elliptical shape of the energy confinement region formed in the elliptical shape in the vibration part A method for adjusting a frequency of a piezoelectric device, wherein the etching region is defined as an etching region, and at least the extraction electrode formed on the step portion is etched as a non-etching region. A method for adjusting a frequency of a piezoelectric device according to claim 1 or 2,
A method for adjusting a frequency of a piezoelectric device, which employs ion milling as the etching, absorbs heat generated during etching by a mask for defining an etching region, and suppresses temperature rise in an etching atmosphere. A piezoelectric device containing a piezoelectric vibrating piece having at least a vibrating portion and a peripheral portion, and a step portion formed between the vibrating portion and the peripheral portion in a package,
Of the excitation electrodes formed in the vibration part, at least than the film thickness of the metal film formed in the site where the extraction electrode that is electrically connected to the input / output electrode formed in the peripheral part is connected, A piezoelectric device characterized in that the thickness of a metal film formed in an energy confinement region in the vibration part is reduced. The piezoelectric device according to claim 4,
A portion for reducing the thickness of the metal film,
Centering on the intersection of the elliptical short axis and the long axis constituting the energy confinement region, the length of the elliptical short axis or the length of the long axis is the inside of a circle drawn as a diameter, Piezoelectric device. The piezoelectric device according to claim 4 or 5, wherein
The piezoelectric device is characterized in that the excitation electrode has a rectangular shape, and the extraction electrode is connected to a corner of the excitation electrode. The piezoelectric device according to any one of claims 4 to 6,
A piezoelectric device characterized in that the piezoelectric vibrating piece is any one of a mesa type, a plano mesa type, a reverse mesa type, and a plano reverse mesa type piezoelectric vibrating piece. When ion milling the excitation electrode mounted on the piezoelectric device package, which has a step between the vibrating part and the peripheral part, and is formed on the vibrating part of the piezoelectric vibrating piece with thickness shear vibration as the main vibration A mask to use,
Composed of metal members,
The length of the short axis of the elliptical shape or the length of the long axis is defined as the diameter around the intersection of the short axis and the long axis constituting the elliptical shape of the energy confinement region where the thickness shear vibration is confined on the excitation electrode. A frequency adjustment mask, wherein a circular opening to be formed is formed by machining.

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