JP7425632B2 - Piezoelectric vibrator container and piezoelectric vibrator - Google Patents

Description

The present invention relates to a piezoelectric vibrator container and a piezoelectric vibrator, and more particularly to a piezoelectric vibrator container in which a piezoelectric vibrating piece is disposed, and a piezoelectric vibrator.

BACKGROUND ART In various electronic devices such as mobile phones and personal digital assistants, piezoelectric vibrators using crystals or the like are used as devices used as time sources, timing sources such as control signals, reference signal sources, and the like. As this type of piezoelectric vibrator, as shown in Patent Document 1, one in which a piezoelectric vibrating piece is hermetically sealed in a cavity formed by a package and a lid is known.
The piezoelectric vibrating piece includes a base having a predetermined length made of a piezoelectric material, a pair of vibrating arms extending side by side from the base, and a pair of fixed vibrating arms extending side by side from both ends of the base on the outside of the vibrating arms. It has a support arm for use.
In a piezoelectric vibrator that stores such a piezoelectric vibrating piece, for example, as shown in Patent Document 1, the metal film at the tip of the vibrating arm of the piezoelectric vibrating piece stored in a package is removed by ion milling. This is how the frequency is adjusted. That is, a mask with an opening window corresponding to the region to be removed of the metal film is placed over the piezoelectric vibrating piece, and ions are irradiated through the opening window to remove the metal film at the tip of the vibrating arm.

By the way, on the inner bottom surface of a package (container) for a piezoelectric vibrator that stores a piezoelectric vibrating piece, an internal electrode is formed to connect two systems of excitation electrodes formed on the piezoelectric vibrating piece and an external electrode. There is.
As the volume of the package becomes smaller due to miniaturization in recent years, the area in which the internal electrodes are arranged becomes smaller, and the tip of the vibrating arm tends to be closer to the internal electrodes.
Furthermore, in the case of a piezoelectric vibrating piece that is fixed with a support arm, the width is wider than that of a so-called cantilever type piezoelectric vibrating piece, so the internal electrodes in the miniaturized package need to be formed even closer to the vibrating arm. be.

Due to the miniaturization of packages and the shape of piezoelectric vibrating pieces, etc., the internal electrodes are formed near the vibrating arms, and if frequency adjustment is performed by ion milling, there is a possibility that the internal electrodes will break. was there.
In other words, in ion milling, ions are irradiated to the tip of the vibrating arm through an opening formed in the mask, but the irradiated ions spread inside the package and reach not only the metal film at the tip of the vibrating arm but also the internal electrodes. In some cases, the internal electrodes were damaged due to ion irradiation.

Japanese Patent Application Publication No. 2006-165968

The present invention aims to avoid breakage of internal wiring due to ion milling.

(1) In the invention as set forth in claim 1, a bottom plate and a weight metal film for frequency adjustment, together with the bottom plate, form a concave portion for accommodating a piezoelectric vibrating piece formed at the tip of a vibrating arm. an annular upper frame disposed on the top of the bottom plate; a mounting portion for mounting a piezoelectric vibrating piece formed on the inner surface of the bottom plate on the side where the upper frame is disposed; A pair of excitation electrodes formed on the piezoelectric vibrating piece; and a pair of internal electrodes formed on the inner surface of the bottom plate and electrically connected via the mounting section, the internal electrodes A piezoelectric vibrator, characterized in that at least a portion of the widthwise outer side of the longitudinally extending portion of the piezoelectric vibrating piece, at least in a portion facing the outer side surface of the weight metal film , is covered with the upper frame. Provide a container.
(2) In the invention as set forth in claim 2, the piezoelectric vibrating reed is provided with a pair of support arms for mounting on both outer sides of the vibrating arm, and the mounting portion corresponds to the support arm. 2. A piezoelectric vibrator container according to claim 1, wherein a pair of piezoelectric vibrator containers are formed at different positions.
(3) The invention according to claim 3 is characterized in that a portion of the internal electrode in the longitudinal direction is covered with the upper frame, and the remaining portion in the longitudinal direction is exposed within the recessed portion. A piezoelectric vibrator container according to claim 2 is provided.
(4) In the invention according to claim 4, the internal electrode extends from the mounting portion to the vibrating arm side of the piezoelectric vibrating piece, and a portion of the internal electrode in the longitudinal direction is formed by the upper frame. There is provided a piezoelectric vibrator container according to claim 1, 2, or 3, characterized in that the piezoelectric vibrator container is covered.
(5) In the invention according to claim 5, the width of the internal electrode covered by the upper frame is 1/3 or less of the width of the upper frame. A piezoelectric vibrator container according to any one of claim 4 is provided.
(6) In the invention according to claim 6, the width of the internal electrode covered by the upper frame is 1/4 or less of the width of the upper frame. A piezoelectric vibrator container according to any one of claim 4 is provided.
(7) In the invention according to claim 7, the piezoelectric vibrator container according to any one of claims 1 to 6, the piezoelectric vibrating piece mounted on the mounting section, and the piezoelectric vibrating piece mounted on the mounting section, A piezoelectric vibrator is provided, comprising: a sealing plate that is connected to an open side surface of a recessed part and hermetically stores the mounted piezoelectric vibrating piece in the recessed part.

According to the present invention, of the pair of internal electrodes formed on the inner surface of the bottom plate, a part of the piezoelectric vibrating piece in the longitudinal direction is covered by the upper frame, so that breakage of internal wiring due to frequency adjustment by ion milling is prevented. can be avoided.

FIG. 2 is an exploded perspective view of a piezoelectric vibrator in which a piezoelectric vibrating piece is arranged in a piezoelectric vibrator container. FIG. 2 is an explanatory diagram showing a side cross section of a piezoelectric vibrator container and a wiring state of internal electrodes on the inner surface of the bottom plate of the container. FIG. 3 is an explanatory diagram showing the wiring state of external electrodes on the back surface of the bottom plate of the piezoelectric vibrator container. FIG. 3 is an explanatory diagram showing the state of the back side of the lower frame of the piezoelectric vibrator container. FIG. 3 is an explanatory diagram of a state in which a piezoelectric vibrating piece is subjected to ion milling. FIG. 7 is an explanatory diagram of a piezoelectric vibrator in a second embodiment.

Hereinafter, preferred embodiments of a piezoelectric vibrating piece and a piezoelectric vibrator of the present invention will be described in detail with reference to FIGS. 1 to 6.
(1) Overview of the Embodiment A piezoelectric vibrator 1 according to the present embodiment is mounted in a piezoelectric vibrator container 2 in which support arms 9a and 9b of a so-called side arm type piezoelectric vibrating piece 6 are formed of metal bumps. They are mounted on the parts 14a and 14b, and sealed with the sealing plate 4 after frequency adjustment by ion milling.
On the inner surface 10f of the bottom plate 10 constituting the piezoelectric vibrator container 2, internal electrodes 31 and 32 are formed as wiring.
In this embodiment, at least a part of the internal electrode 32 formed on the inner surface 10 f of the bottom plate around the opening window 81 in ion milling (the side away from the opening window 81 ) is located between the bottom plate 10 and the upper frame 11 . It is formed.

That is, a portion of the internal electrode 32 is covered with the upper frame 11. As a result, even if the exposed portion of the internal electrode 32 that is not covered by the upper frame 11 is damaged by ion milling, the covered portion will remain, making it possible to reliably avoid disconnection of the internal electrode 32. can.
Even the piezoelectric vibrator 1 provided with the piezoelectric vibrating piece 6 can be manufactured without degrading the yield or characteristics. Therefore, further miniaturization of the piezoelectric vibrator 1 is possible.

Although it is possible to cover the entire internal electrode 32 around the opening window 81 with the upper frame 11, it is preferable to partially cover it in order to maintain the connection strength between the bottom plate 10 and the upper frame 11. The upper frame 11 covers the internal electrodes 32 by 1/3 or less, preferably 1/4 or less of the width of the upper frame 11.
Further, in order to enable confirmation of the arrangement state of the internal electrodes 32 by visual inspection, image recognition, etc., it is preferable that the area covered by the upper frame 11 be a part of the area.

(2) Details of embodiment [first embodiment]
FIG. 1 is an exploded perspective view of a piezoelectric vibrator 1 in which a piezoelectric vibrating piece 6 is arranged in a piezoelectric vibrator container 2 according to the first embodiment.
As shown in FIG. 1, a piezoelectric vibrator 1 according to the present embodiment includes a piezoelectric vibrator container 2 having a housing space therein, a sealing plate 4 for hermetically sealing the piezoelectric vibrator container 2, and a piezoelectric vibrator container 2. This is a ceramic package type surface-mounted vibrator that includes a piezoelectric vibrating piece 6 housed inside.
The piezoelectric vibrator 1 is formed to have a length of about 1.6 mm and a width of about 1.2 mm, as an example of the size in a plan view.
In addition, since the piezoelectric vibrator 1 of this embodiment has a symmetrical structure, both parts arranged symmetrically, such as the vibrating arm part 7a and the vibrating arm part 7b, are represented by the same number, and both parts are expressed by the same number. In order to distinguish between the two, one will be described with a distinguishing mark a and the other with a distinguishing mark b. However, in the explanation, the distinguishing symbols are omitted as appropriate, but in this case, they refer to each part.

The piezoelectric vibrating piece 6 is a so-called tuning fork-shaped vibrating piece made of a piezoelectric material such as crystal, lithium tantalate, or lithium niobate, and vibrates when a predetermined voltage is applied. In this embodiment, a piezoelectric vibrating piece formed using crystal as a piezoelectric material will be described as an example.
The piezoelectric vibrating piece 6 is a so-called side arm type crystal vibrating piece, and includes a pair of vibrating arms 7a and 7b extending in parallel from a base 8, and a pair of vibrating arms 7a and 7b extending from the base 8 in the same direction on the outside of the vibrating arms 7. A pair of support arms 9a and 9b are provided. The piezoelectric vibrating piece 6 is held in the mounting parts 14a, 14b inside the piezoelectric vibrator container 2 by the supporting arms 9a, 9b.

The pair of vibrating arms 7a and 7b are arranged parallel to each other, and vibrate with the end on the base 8 side as a fixed end and the tip as a free end.
The pair of vibrating arms 7a, 7b has widened portions 71a, 71b, which are wider on both sides than the base side, formed on their free end sides. Further, a groove portion along the longitudinal direction is formed in the vibrating arm portions 7a, 7b in a range from the end on the base portion 8 side to this side of the widened portion 71. Note that a piezoelectric vibrating piece without the widened portion 71 and the groove portion may be used.

Although not shown, in the piezoelectric vibrating piece 6 of this embodiment, the tip portions (widened portions 71a, 71b) of the vibrating arms 7a, 7b are provided with a vibration state adjusted to vibrate within a predetermined frequency range (frequency adjustment). ) is formed with a weight metal film.
Then, after the piezoelectric vibrating piece 6 is mounted on the mounting parts 14a, 14b of the piezoelectric vibrator container 2, a part of the weight metal film formed on the tips of the vibrating arms 7a, 7b is removed by ion milling. This allows the frequency to be within the nominal frequency range of the device.
Note that the frequency can be adjusted by removing an appropriate amount of the weight metal film of the piezoelectric vibrating piece 6 by, for example, irradiating it with a laser beam before mounting it on the piezoelectric vibrator container 2. Ion milling in this case is performed as a final adjustment of frequency.

The piezoelectric vibrator container 2 is formed into a generally rectangular parallelepiped shape and includes a recessed portion 3 and a seal ring 13 for sealing the recessed portion 3.
Although the piezoelectric vibrator container 2 of this embodiment does not include the sealing plate 4 that is joined to the seal ring 13 for airtight sealing, the piezoelectric vibrator container 2 can also include the sealing plate 4. .
The concave portion 3 includes a flat bottom plate 10 which are joined to each other in an overlapping state, an annular upper frame 11 which is joined to the upper surface of the bottom plate 10, and an annular lower frame 12 which is joined to the lower surface of the bottom plate 10. ing.

At the four corners of the joined bottom plate 10, upper frame 11, and lower frame 12, notches 15 having a quarter-arc shape in plan view are formed throughout the thickness direction. These bottom plate 10, upper frame 11, and lower frame 12 are made by, for example, stacking and bonding three wafer-shaped ceramic substrates, forming a plurality of through holes penetrating both ceramic substrates in a matrix, and then forming each through hole. It is fabricated by cutting both ceramic substrates into a grid pattern using . At this time, the through hole is divided into four parts, thereby forming the cutout part 15.

Note that the bottom plate 10, the upper frame 11, and the lower frame 12 are made of ceramic, but specific ceramic materials include, for example, HTCC (High Temperature Co-Fired Ceramic) made of alumina, and LTCC (made of glass ceramic). Low Temperature Co-Fired Ceramic), etc.

In the concave portion 3, an upper frame 11, a bottom plate 10, and a lower frame 12 are stacked in this order from above, and the upper frame 11 and the lower frame 12 are bonded to the bottom plate 10 by sintering or the like. That is, the upper frame 11 and the lower frame 12 are integrated with the bottom plate 10.
Although not shown in FIG. 1, internal electrodes 31 and 32 and external electrodes 23 and 24 are formed on both sides of the bottom plate 10, with some of the internal electrodes being sandwiched between the bottom plate 10 and the upper frame 11. It is formed in a closed state.
Moreover, mounting portions 14a and 14b for mounting the piezoelectric vibrating piece 6 are formed on the bottom plate inner surface 10f of the bottom plate 10. The mounting portions 14a, 14b are formed of gold bumps on the internal electrodes 31a, 31b (see FIG. 2).

The upper frame 11 and the lower frame 12 are formed into an annular shape with the inside penetrated through. The inner surface 11n of the piezoelectric vibrator 1 and the inner surface 12n of the lower frame 12 (see FIG. 2) are both formed into a rectangular shape in plan view with rounded corners.
Out of the notches 15 formed in the concave portion 3 , external electrodes 22 are formed at four locations in the notches 15 of the lower frame 12 .

The seal ring 13 is a conductive frame-shaped member that is slightly smaller than the outer shape of the concave portion 3, and is joined to the upper surface of the upper frame 11. Specifically, the seal ring 13 is bonded to the upper frame 11 by baking with a soldering material such as silver solder, or formed on the upper frame 11 (for example, by electrolytic plating, electroless plating, etc.). They are joined by welding or the like to a metal bonding layer that has been deposited (by vapor deposition, sputtering, etc.).

The material for the seal ring 13 includes, for example, a nickel-based alloy, and specifically, it may be selected from Kovar, Elinvar, Invar, 42 alloy, and the like. In particular, it is preferable to select a material for the seal ring 13 that has a thermal expansion coefficient close to that of the bottom plate 10 and the upper frame 11, which are made of ceramic. For example, when the bottom plate 10 and the upper frame 11 are made of alumina with a thermal expansion coefficient of 6.8 x 10-6/°C, the seal ring 13 is made of Kovar with a thermal expansion coefficient of 5.2 x 10-6/°C. It is preferable to use 42 alloy having a thermal expansion coefficient of 4.5 to 6.5×10-6/°C.

The sealing plate 4 is a conductive substrate placed on the seal ring 13. The sealing plate 4 is hermetically joined to the piezoelectric vibrator container 2 by being welded to the seal ring 13 by seam welding in which a roller electrode is moved in contact with it, laser welding, ultrasonic welding, or the like.
A space defined by the sealing plate 4, the seal ring 13, the inside of the upper frame 11, and the bottom plate inner surface 10f of the bottom plate 10 functions as an airtightly sealed cavity.

FIG. 2 shows the wiring state of the internal electrodes on the side cross section of the piezoelectric vibrator container 2 and the inner surface 10f of the bottom plate of the container.
FIG. 2A shows a longitudinal cross section passing through the mounting portion 14b disposed on the bottom plate 10. FIG. FIG. 2(b) shows the state of the bottom plate inner surface 10f of the bottom plate 10 when the piezoelectric vibrator container 2 is viewed from above and the seal ring 13 and the upper frame 11 are seen through.
The dotted frame in FIG. 2(b) represents the inner surface 11n of the upper frame 11.
As shown in FIG. 2(b), through electrodes 30a, 30b, and 30c penetrating in the thickness direction are formed at three of the four corners of the bottom plate 10. The through electrode 30 is formed, for example, by filling a through hole formed in the bottom plate 10 with metal paste (conductive paste), inserting a metal pin, or plating the inner peripheral surface.

The through electrodes 30a and 30b are disposed at substantially diagonal positions, with a portion thereof covering the inner surface of the upper frame 11 indicated by a dotted line. That is, a portion of the end surface of the through electrodes 30a and 30b on the upper frame 11 side is covered by the upper frame 11.
The opposite end surfaces of the through electrodes 30a and 30b are connected to external electrodes 24a and 24b via connection electrodes 25a and 25b formed on the outer surface 10r of the bottom plate 10 (see FIG. 3).

On the other hand, the through electrode 30c is formed at a position where the entire end surface on the upper frame 11 side is covered by the upper frame 11. The through electrode 30c is provided to ensure electrical continuity when the seal ring 13 is attached by plating. Therefore, while the through electrodes 30a and 30b are formed only on the bottom plate 10, the through electrode 30c is formed through the upper frame 11 in addition to the bottom plate 10.
The end surface of the through electrode 30c on the bottom plate 10 side is connected to the external electrode 23 via the connection electrode 25c formed on the outer surface 10r of the bottom plate (see FIG. 3), and the end surface on the opposite side is formed on the entire upper surface of the upper frame 11. It is connected to a metallized layer (not shown).

Internal electrodes 31a, 31b, which are larger in size than the mounting parts 14a, 14b, are formed in an oval shape between the mounting parts 14a, 14b and the inner surface 10f of the bottom plate.
Note that, as shown in FIG. 2, the mounting parts 14a, 14b and the internal electrodes 31a, 31b are arranged on one side (left side in the drawing) of the center in the longitudinal direction (left-right direction in the drawing). The piezoelectric vibrating piece 6 is mounted in such a direction that the base 8 is located on one side.

An electrode connected to the connection electrode 33c is formed inside the inner surface 11n of the upper frame 11 on the side of the through electrode 30c among the four corners of the inner surface 10f of the bottom plate.
This electrode is an index mark 35 for determining the orientation of the recessed portion 3 (left and right orientation in the figure) by image recognition.

On the inner surface of the bottom plate 10f, circular connection electrodes 33a to 33c are formed at positions corresponding to the through electrodes 30a to 30c. These connection electrodes 33a to 33c are also partially covered by the upper frame 11 on the outside when viewed from the center of the inner surface 10f of the bottom plate.
The internal electrode 31a and the connection electrode 33a are connected by the internal electrode 32a, and the internal electrode 31b and the connection electrode 33b are connected by the internal electrode 32b.
That is, as shown in FIG. 2B, the internal electrodes 32a and 32b extend outward from the internal electrodes 31a and 31b in the width direction (vertical direction in the drawing), and are bent in the direction away from the center in the longitudinal direction. The tips are formed so as to be connected to the connection electrodes 33a and 33b.
A portion of the internal electrodes 32a and 32b on the outside in the width direction of the portion extending in the longitudinal direction is covered with the upper frame 11.
Thereby, even if the exposed portion of the internal electrode 32 that is not covered by the upper frame 11 is damaged by ion milling, disconnection of the internal electrode 32 can be reliably avoided.

FIG. 3 is an explanatory diagram showing the wiring state of external electrodes on the bottom plate rear surface 10r of the piezoelectric vibrator container 2. As shown in FIG. Note that the bottom plate back surface 10r shown in FIG. 3 is a transparent view of the piezoelectric vibrator container 2 seen from above and the top frame 11 and the bottom plate 10.
As shown in FIG. 3, external electrodes 23 are formed at four locations on the outer surface 10r of the bottom plate to be connected to external electrodes 22 (see FIG. 1) formed in the notches 15 at the four corners of the lower frame 12.
Further, connection electrodes 25a to 25c are formed at positions corresponding to the through electrodes 30a to 30c (see FIG. 2(b)). Of these, the connection electrode 25c is connected to the external electrode 23.

Further, external electrodes 24a and 24b are formed on the outer surface 10r of the bottom plate.
The external electrode 24a is connected to the connection electrode 25a, thereby being connected to the mounting portion 14a via the through electrode 30a, the internal electrode 32a, and the internal electrode 31a.
The external electrode 24b is connected to the connection electrode 25b, thereby being connected to the mounting portion 14b via the through electrode 30b, the internal electrode 32b, and the internal electrode 31b.
The external electrodes 24a and 24b are electrodes for mounting an IC on the back surface 10r of the bottom plate.

The dotted frame shown in FIG. 3 represents the inner surface 12n of the lower frame 12.
That is, among the external electrodes 23, external electrodes 24a, 24b, and connection electrodes 25a to 25c formed on the bottom plate rear surface 10r of the bottom plate 10, the area outside the inner surface 12n of the lower frame 12 indicated by the dotted line is covered with a lower frame 12.

FIG. 4 shows the state of the back side of the lower frame 12 of the piezoelectric vibrator container 2. As shown in FIG.
On the back side of the lower frame 12, external electrodes 21 are formed at four corners. Each of the four external electrodes 21 is connected to connection electrodes 22 (see FIG. 1) formed in the notches 15 at the four corners of the lower frame 12.
Although not shown in FIG. 4, when the piezoelectric vibrator container 2 is viewed from the bottom (lower frame 12 side), there is a dotted line inside the inner surface 12n of the lower frame 12. There are external electrodes 23, 24a, 24b and connection electrodes 25a to 25c within the side surface 12n.

The concave portion 3 (see FIG. 1) of this embodiment is made of ceramic such as alumina, and is made by laminating and firing a plurality of flexible ceramic sheet materials called green sheets to integrate them. It is formed. Each sheet material is appropriately selected in consideration of the thickness and number of the lower frame 12, bottom plate 10, and upper frame 11.
On each sheet material, the various electrodes (internal electrodes and external electrodes) described above are formed by, for example, conductor printing, and through electrodes 30a to 30c are formed, and then the lower frame 12, the bottom plate 10, and the upper frame 11 are laminated in this order. After that, the whole thing is fired at the same time.
After firing the concave portion 3, a layer of brazing material is formed on the metallized layer formed on the upper surface of the upper frame 11, and the seal ring 13 is joined thereon by seam welding, thereby completing the piezoelectric vibrator container 2. is formed.

Next, manufacturing of the piezoelectric vibrator 1 including mounting the piezoelectric vibrating piece 6 on the piezoelectric vibrator container 2 configured as shown in FIGS. 2 to 4 and frequency adjustment by ion milling will be described.
A first excitation electrode and a second excitation electrode for excitation, and electrodes from both excitation electrodes to vibrating arms 7a and 7b are connected to the piezoelectric vibrating piece 6 in advance. Moreover, a weight metal film for frequency adjustment is formed on the widened portions 71a and 71b at the tips of the vibrating arms 7a and 7b.
Furthermore, the frequency of the piezoelectric vibrating piece 6 to be mounted is adjusted to a predetermined level in advance by removing the weight metal film before mounting.

FIG. 5 is an explanatory diagram showing a state in which the piezoelectric vibrating piece 6 is subjected to ion milling.
First, the piezoelectric vibrating piece 6 is placed on the mounting portions 14a and 14b of the piezoelectric vibrator container 2. That is, after applying a conductive adhesive onto the mounting parts 14a and 14b, the support arms 9a and 9b of the piezoelectric vibrating piece 6 are placed on each conductive adhesive.
Thereafter, the piezoelectric vibrating piece 6 is mounted on the piezoelectric vibrating piece 2 by baking the piezoelectric vibrating piece 2 on which the piezoelectric vibrating piece 6 is placed to form a conductive adhesive.

The piezoelectric vibrator container 2 in which the piezoelectric vibrating piece 6 is mounted is set in a jig in a chamber (not shown).
Then, as shown in FIG. 5, a mask 80 in which an opening window 81 (frame surrounded by a dashed-dotted line) is formed in the peripheral region of the widened portions 71a and 71b, which are the regions to be trimmed, of the piezoelectric vibrating piece 6 is placed. The piezoelectric vibrator is set on the container 2 (mask setting step).
As a result, in the piezoelectric vibrating piece 6, the base 8, the support arm 9, the vibrating arm 7 other than the widened part 71, and the end of the widened part 71 on the base 8 side are covered with the mask 80, and the widened part 71 is covered with the mask 80. The tip side is exposed.
The reason why the base 8 side of the vibrating arm 7 is covered with the mask 80 is to prevent the first excitation electrode and the second excitation electrode formed on the vibrating arm 7 from being removed by ion milling.

Subsequently, ion milling is performed on the piezoelectric vibrator container 2 set in the chamber. Specifically, the pressure inside the chamber is reduced and a process gas such as argon is introduced. When an accelerating voltage is applied in this state, the ionized process gas passes through the opening window 81 of the mask 80 and collides with the weight metal of the vibrating arm 7 .
As a result, the weight metal film of the vibrating arm 7 is thrown off from the surface layer, and the mass of the vibrating arm 7 changes, thereby changing the frequency of the vibrating arm.
In the piezoelectric vibrator container 2 of this embodiment, as shown by the dotted line in FIG. Therefore, even if the uncovered portion of the internal electrode 32a is removed by the process gas, it is possible to avoid disconnection of the internal electrode 32a.

After ion milling the widened portion 71 of the piezoelectric vibrating piece 6, the sealing plate 4 is seam welded to the seal ring 13 of the piezoelectric vibrator container 2, thereby producing piezoelectric vibration in which the piezoelectric vibrating piece 6 is sealed in the piezoelectric vibrating piece 2. Child 1 is completed.

[Second embodiment]
Next, a second embodiment of the piezoelectric vibrator container 2 and the piezoelectric vibrator 1 will be described.
In the first embodiment, the piezoelectric vibrator 1 is formed using the piezoelectric vibrator container 2 having a length of about 16 mm and a width of about 12 mm in plan view.
On the other hand, in the second embodiment, a piezoelectric vibrator container 2 having the same length of 16 mm in plan view and a narrower width of 10 mm is used. Note that what is mounted inside is the same as the piezoelectric vibrating piece 6 described in the first embodiment.

FIG. 6 is an explanatory diagram of the piezoelectric vibrator container 2 and the piezoelectric vibrator 1 in the second embodiment, and shows the state in which the piezoelectric vibrating piece 6 is subjected to ion milling in the same manner as in FIG. 5 in comparison with the first embodiment. represents.
As shown in FIG. 6, in the piezoelectric vibrator container 2 of the second embodiment, the distance between the support arms 9a, 9b of the piezoelectric vibrating piece 6, which has a narrow width of 10 mm, and the inner surface 11n of the upper frame 11 is Becomes shorter.
Even in this case, as in the first embodiment, a portion of the longitudinally extending region of the internal electrodes 32a, 32b on the outside in the width direction is covered with the upper frame 11, and furthermore, the tip thereof is covered with the connecting electrode 33a, 33b. Note that a portion of the outer side of the connection electrodes 33a and 33b is also covered with the upper frame 11 as in the first embodiment.
In the piezoelectric vibrator container 2 of the second embodiment, the position of the internal electrode 32a is closer to the opening window 81 for ion milling than in the first embodiment, so it is easier to be irradiated with the ion beam. By covering a portion in the longitudinal direction with the upper frame 11, disconnection can be reliably avoided.

In each of the above embodiments, a case has been described in which a portion of the longitudinally extending portion of the internal electrodes 32a, 32b in the width direction is covered with the upper frame 11.
On the other hand, only the internal electrode 32a extending from the internal electrode 31 toward the widened portions 71a and 71b is likely to be ion irradiated by ion milling.
Therefore, the internal electrode 32b extending from the internal electrode 31 toward the side away from the widened portions 71a and 71b (towards the base 8) may be formed so that the entire length thereof is not covered by the upper frame 11.

In the described embodiment, a case has been described in which a part of the internal electrode is covered with the upper frame 11 when a so-called side arm type piezoelectric vibrating piece 6 is mounted.
On the other hand, there are piezoelectric vibrators in which the base 8 is joined to the mounting part without forming a support arm, or in which a single support arm extending from the base 8 is formed between both vibrating arms 7. When mounting a piezoelectric vibrating piece that connects a support single arm to a mounting part, internal wiring is installed between the tips of the vibrating arms 7a and 7b on which a weight metal film for frequency adjustment is formed and the upper frame 11. It can also be applied when . In this case, by covering a portion of the internal wiring in the longitudinal direction with the upper frame 11 as in the embodiment, it is possible to avoid disconnection of the internal wiring due to ion milling.

1 Piezoelectric vibrator 2 Piezoelectric vibrator container 3 Concave portion 4 Sealing plate 6 Piezoelectric vibrating piece 7 Vibrating arm portion 71 Width portion 8 Base portion 9 Support arm portion 10 Bottom plate 10f Bottom plate inner surface 10r Bottom plate outer surface 11 Upper frame 11n Inner surface 12 Lower frame 12n Inner surface 13 Seal ring 14 Mounting part 15 Notch part 21, 22, 23, 24 External electrode 25 Connection electrode 30 Through electrode 31, 32 Internal electrode 33 Connection electrode 35 Index mark 80 Mask 81 Opening window

Claims (7)

The bottom plate and
an annular upper frame disposed on the top of the bottom plate, which forms, together with the bottom plate, a concave portion for accommodating a piezoelectric vibrating piece in which a weight metal film for frequency adjustment is formed at the tip of the vibrating arm; and,
a mounting portion for mounting a piezoelectric vibrating piece formed on the inner surface of the bottom plate on the side where the upper frame is disposed;
a pair of excitation electrodes formed on the piezoelectric vibrating piece; and a pair of internal electrodes formed on the inner surface of the bottom plate and electrically connected via the mounting section;
Equipped with
The internal electrode is at least a portion facing the outer side surface of the weight metal film, and a portion of the widthwise outer side of the portion extending in the longitudinal direction of the piezoelectric vibrating piece is covered with the upper frame.
A piezoelectric vibrator container characterized by: A piezoelectric vibrating piece is mounted, which has a pair of support arms for mounting on both sides of the vibrating arm.
A pair of the mounting portions are formed at positions corresponding to the support arm portions,
The piezoelectric vibrator container according to claim 1, characterized in that: A portion of the internal electrode in the longitudinal direction is covered with the upper frame, and the remaining portion in the longitudinal direction is exposed within the recessed portion.
The piezoelectric vibrator container according to claim 2, characterized in that: The internal electrode extends from the mounting portion to the vibrating arm side of the piezoelectric vibrating piece, and a portion of the internal electrode in the longitudinal direction is covered with the upper frame.
The piezoelectric vibrator container according to claim 1, claim 2, or claim 3, characterized in that: The width of the internal electrode covered by the upper frame is 1/3 or less of the width of the upper frame,
The piezoelectric vibrator container according to any one of claims 1 to 4, characterized in that: The width of the internal electrode covered by the upper frame is 1/4 or less of the width of the upper frame,
The piezoelectric vibrator container according to any one of claims 1 to 4, characterized in that: A piezoelectric vibrator container according to any one of claims 1 to 6,
a piezoelectric vibrating piece mounted on the mounting section;
a sealing plate that is connected to an open side surface of the recessed portion and hermetically stores the mounted piezoelectric vibrating piece in the recessed portion;
A piezoelectric vibrator characterized by comprising:

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