JP2017076913A - Package and piezoelectric vibrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a package and a piezoelectric vibrator capable of inhibiting a seal ring from protruding from the inner side surface of a frame part or the outer side surface of the frame part in a mounting substrate.SOLUTION: A package includes: a mounting substrate 22 having a recess 21 having in which a piezoelectric vibration piece 3 is housed; a seal ring 24 which is arranged on the frame part 41 of the mounting substrate 22 and surrounds the recess 21 in a plan view seen from a thickness direction T; and a sealing plate 23 which is joined onto the sealing ring 24 and blocks the recess 21. In a plan view, in the sealing ring 24, the outline of the ring inner side surface is larger than that of the inner side surface of the frame part 41, and the outline of the ring outer side surface is smaller than that of the outer side surface of the frame part 41.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a package and a piezoelectric vibrator.

  For example, as a package in which an electronic component such as a piezoelectric vibrating piece is enclosed, for example, a configuration as shown in Patent Document 1 is known. This type of package includes a mounting substrate having a recess that accommodates an electronic component, a seal ring disposed on the mounting substrate, and a lid that is bonded onto the seal ring and closes the recess of the mounting substrate. Yes.

The seal ring is fixed on the side wall portion of the mounting substrate by, for example, adhesion. The seal ring surrounds the recess in a plan view viewed from the thickness direction of the mounting substrate.
The lid is fixed to the seal ring by welding or the like (for example, seam welding).
The package encloses electronic components in a cavity defined by the mounting substrate, the seal ring, and the lid.

JP 2002-111426 A

  However, in the configuration of Patent Document 1 described above, the seal ring is displaced from a desired position on the side wall portion of the mounting substrate due to, for example, the effect of a load or heat acting when the lid body and the seal ring are welded. There is a case. In particular, with the recent miniaturization of piezoelectric vibrators, the degree of relative displacement between the seal ring and the mounting substrate increases. As a result, in a plan view, for example, the seal ring may protrude from the inner surface or the outer surface of the side wall portion of the mounting substrate. In this case, when the lid and the seal ring are welded, a load is locally applied to the mounting substrate via the seal ring, which may lead to damage of the mounting substrate or the like.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a package and a piezoelectric vibrator capable of suppressing the seal ring from protruding with respect to the inner surface or the outer surface of the side wall portion of the mounting substrate. It is to be.

  In order to solve the above-described problem, a package according to one embodiment of the present invention is disposed on a mounting substrate having a recess for accommodating an electronic component and a side wall portion of the mounting substrate, and is viewed from the thickness direction of the mounting substrate. A ring member that surrounds the recess in a plan view; and a lid that is joined on the ring member to close the recess, and in the plan view, the ring member has a ring inner surface whose contour is the side wall portion. The contour of the outer surface of the ring is larger than the contour of the inner surface of the side wall, and the contour of the outer surface of the ring is smaller than the contour of the outer surface of the side wall of the side wall.

  According to this configuration, the ring member can easily be accommodated within the width of the side wall portion in plan view. In this case, for example, even if the ring member deviates from a desired position on the side wall due to the influence of a load or heat acting at the time of joining the lid and the ring member, the inner side of the side wall or the outer side of the side wall The ring member can be prevented from protruding. Therefore, at the time of joining the lid and the ring member, it is possible to suppress a load from acting locally on the mounting substrate via the ring member, and it is possible to suppress damage to the mounting substrate and the like.

In the above aspect, of the ring member, the inner surface of the ring is disposed closer to the outer surface of the side wall than the inner surface of the side wall, and the outer surface of the ring is closer to the inner surface of the side wall than the outer surface of the side wall. The distance between the inner surface of the ring and the inner surface of the side wall and the distance between the outer surface of the ring and the outer surface of the side wall may be equal to each other.
According to this configuration, the distance between the inner surface of the ring and the inner surface of the side wall and the distance between the outer surface of the ring and the outer surface of the side wall are equal to each other. It is possible to reliably suppress the protrusion.

A piezoelectric vibrator according to one aspect of the present invention includes the package according to one aspect of the present invention, and a piezoelectric vibrating piece accommodated in the recess.
According to this configuration, since damage to the mounting substrate or the like can be suppressed as described above, it is possible to suppress a decrease in the degree of vacuum in the cavity defined by the mounting substrate, the ring member, and the lid. As a result, a piezoelectric vibrator having excellent vibration characteristics can be provided.

  According to one embodiment of the present invention, the seal ring can be prevented from protruding from the inner side surface or the outer side surface of the side wall of the mounting substrate.

1 is an external perspective view of a piezoelectric vibrator according to an embodiment of the present invention. It is a top view of the piezoelectric vibrator which shows the state which removed the sealing board. FIG. 3 is a cross-sectional view corresponding to line III-III in FIG. 2. 1 is an exploded perspective view of a piezoelectric vibrator according to an embodiment of the present invention. It is a top view of a piezoelectric vibrating piece. FIG. 4 is an enlarged view of a portion VI in FIG. 3.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.
[Piezoelectric vibrator]
FIG. 1 is an external perspective view of a piezoelectric vibrator 1 according to an embodiment of the present invention. FIG. 2 is a plan view of the piezoelectric vibrator 1 with the sealing plate 23 removed. 3 is a cross-sectional view corresponding to the line III-III in FIG. FIG. 4 is an exploded perspective view of the piezoelectric vibrator 1 according to the embodiment.
As shown in FIGS. 1 to 4, the piezoelectric vibrator 1 is a so-called ceramic package type surface mount vibrator. The piezoelectric vibrator 1 includes a package 2 having a cavity C hermetically sealed therein, and a piezoelectric vibrating piece 3 accommodated in the cavity C. The piezoelectric vibrator 1 has a rectangular parallelepiped shape. Therefore, in the present embodiment, the longitudinal direction of the piezoelectric vibrator 1 is referred to as the longitudinal direction L in the plan view, the lateral direction is referred to as the width direction W, and the direction perpendicular to the longitudinal direction L and the width direction W is the thickness. It is called direction T.

<Piezoelectric vibrating piece>
FIG. 5 is a plan view of the piezoelectric vibrating piece 3.
As shown in FIG. 5, the piezoelectric vibrating piece 3 is made of a piezoelectric material such as quartz, lithium tantalate, or lithium niobate. The piezoelectric vibrating piece 3 vibrates when a predetermined voltage is applied. Note that the longitudinal direction, the width direction, and the thickness direction of the piezoelectric vibrating piece 3 coincide with the longitudinal direction L, the width direction W, and the thickness direction T of the piezoelectric vibrator 1 described above.

The piezoelectric vibrating piece 3 is a so-called side arm type piezoelectric vibrating piece. Specifically, the piezoelectric vibrating piece 3 includes a base 11, a pair of vibrating arms (a first vibrating arm 12 and a second vibrating arm 13), and a pair of supporting arms (a first supporting arm 14 and a first vibrating arm 13). 2 support arms 15).
Each of the vibrating arm portions 12 and 13 extends in a cantilevered manner along the longitudinal direction L from the base portion 11. The vibrating arm portions 12 and 13 are arranged side by side in the width direction W. Each of the vibrating arm portions 12 and 13 vibrates in a direction (width direction W) in which the proximal end portion is a fixed end and the distal end portion is a free end to approach and separate from each other. Each of the vibrating arm portions 12 and 13 includes main body portions 12A and 13A located at the base end portion and weight portions 12B and 13B located at the distal end portion.

  Grooves 20 that are recessed in the thickness direction T and that extend in the longitudinal direction L are formed on both surfaces of the main body portions 12A and 13A in the thickness direction T, respectively. Note that two systems of excitation electrodes (not shown) for vibrating the vibrating arm portions 12 and 13 in the width direction W are formed on the outer surfaces of the main body portions 12A and 13A. Each excitation electrode is patterned in a state of being electrically insulated from each other. Each excitation electrode is formed of a laminated film of, for example, Cr—Au.

  The weight portions 12B and 13B are extended in the longitudinal direction L from the tip portions of the main body portions 12A and 13A, respectively. The width in the width direction W of the weight portions 12B and 13B is wider than the width of the main body portions 12A and 13A. Thereby, the mass of the tip part of each vibration arm part 12 and 13 and the moment of inertia at the time of vibration can be increased, and each vibration arm part 12 and 13 is compared with the piezoelectric vibration piece which does not have weight parts 12B and 13B. Can be shortened.

  The base portion 11 integrally connects the base end portions of the vibrating arm portions 12 and 13. In addition, the both end surfaces of the width direction W in the base 11 are located outside the vibrating arm portions 12 and 13 (main body portions 12A and 13A).

  Each support arm part 14 and 15 is formed in L shape by planar view. The support arm portions 14 and 15 surround the base portion 11 and the vibrating arm portions 12 and 13 (main body portions 12 and 13A) from the outside in the width direction W. Specifically, the support arm portions 14 and 15 project from the both end surfaces of the base portion 11 in the width direction W toward the outside of the width direction W, and then extend along the longitudinal direction L to the vibration arm portions 12 and 13. Extends in parallel with. Mount electrodes (not shown) for mounting the piezoelectric vibrating reed 3 on the package 2 are provided on at least the back surfaces of the support arm portions 14 and 15, respectively.

  Each mount electrode is connected to a corresponding excitation electrode among the above-described excitation electrodes via a routing electrode (not shown). The lead-out electrodes are formed in paths from the support arm portions 14 and 15 to the vibration arm portions 12 and 13 via the base 11.

<Package>
As shown in FIGS. 1 to 4, the package 2 includes a mounting substrate 22 having a recess 21 that accommodates the piezoelectric vibrating piece 3, a sealing plate (lid) 23 that closes the recess 21 of the mounting substrate 22, and a mounting substrate. And a sealing ring (ring member) 24 that joins the sealing plate 22 and the sealing plate 23.

  The mounting substrate 22 is formed in a box shape that opens upward (one side in the thickness direction T). The mounting substrate 22 is configured by laminating a first substrate 31 and a second substrate 32 made of a ceramic material in the thickness direction T. As the ceramic material used for each of the substrates 31 and 32, for example, HTCC (High Temperature Co-Fired Ceramic) made of alumina, LTCC (Low Temperature Co-Fired Ceramic) made of glass ceramics, or the like can be used. is there. Further, the mounting substrate 22 may be configured by a single substrate or may be configured by stacking three or more substrates.

  The first substrate 31 is formed in a rectangular shape in plan view as viewed from the thickness direction T. The upper surface of the first substrate 31 constitutes the bottom surface of the recess 21. On the lower surface of the first substrate 31 (the surface facing the other in the thickness direction T), a pair of external electrodes 35 and 36 are formed with an interval in the longitudinal direction L. The external electrodes 35 and 36 are configured by a single layer film made of a single metal formed by, for example, vapor deposition or sputtering, or a stacked film in which different metals are stacked.

As shown in FIGS. 2 to 4, the second substrate 32 is integrally bonded to the upper surface of the first substrate 31 by sintering or the like. The second substrate 32 includes a frame part (side wall part) 41 and a mounting part 42.
The frame portion 41 is formed in a rectangular frame shape in which the outline of the outer surface of the frame portion has the same size as the outline of the outer surface of the first substrate 31 in a plan view as viewed from the thickness direction T.

  The mounting portion 42 protrudes from the pair of long side portions (portions extending in the longitudinal direction L) of the frame portion 41 toward the inside in the width direction W. An electrode pad 43 is formed on the mounting portion 42. Similarly to the external electrodes 35 and 36 described above, the electrode pad 43 is configured by a single-layer film made of a single metal formed by, for example, vapor deposition or sputtering, or a stacked film in which different metals are stacked. The electrode pads 43 are electrically connected to corresponding external electrodes 35 and 36 through through wirings (not shown) that penetrate the mounting substrate 22 in the thickness direction T.

  The inner surface of the second substrate 32 (the frame portion 41 and the mounting portion 42) constitutes the inner surface of the recess 21. In the present embodiment, the thickness of the second substrate 32 is equal to or greater than the thickness of the first substrate 31.

FIG. 6 is an enlarged view of a portion VI in FIG.
As shown in FIGS. 2 and 6, the seal ring 24 is a conductive frame-like member that is slightly smaller than the outer shape of the mounting substrate 22. In plan view, the width of the seal ring 24 is narrower than the width of the frame portion 41. Specifically, in plan view, the contour of the inner surface of the ring of the seal ring 24 is larger than the contour of the inner surface of the frame portion of the frame portion 41 described above. Further, in the plan view, the contour of the ring outer surface of the seal ring 24 is smaller than the contour of the frame portion outer surface of the frame portion 41. The width of the seal ring 24 is preferably set to about 60% to 80% with respect to the width of the frame portion 41.

  The seal ring 24 is bonded onto the frame part 41 in the second substrate 32. The seal ring 24 is bonded onto the second substrate 32 by, for example, baking with a brazing material such as silver brazing, soldering material, or an adhesive. Moreover, as a material of the seal ring 24, for example, a laminate such as Kov / Ni / Au is preferably used.

  As shown in FIG. 6, the inner surface of the ring of the seal ring 24 is disposed closer to the outer surface of the frame portion than the inner surface of the frame portion. The ring outer surface of the seal ring 24 is disposed closer to the inner surface of the frame portion than the outer surface of the frame portion. That is, the seal ring 24 is within the width of the frame portion 41 in plan view. In the present embodiment, the distance between the inner surface of the ring and the inner surface of the side wall (internal shape difference D1) and the distance between the outer surface of the ring and the outer surface of the side wall (outer shape difference D2) are equal to each other. The inner shape difference D1 and the outer shape difference D2 can be appropriately changed. However, the inner shape difference is preferably equal to or less than the outer shape difference from the viewpoint of reducing the size of the seal ring 24 and the like.

  The sealing plate 23 is formed in a plate shape in plan view as viewed from the thickness direction T. The sealing plate 23 is joined (for example, seam welding) on the seal ring 24 to hermetically seal the recess 21. The space defined by the mounting substrate 22, the sealing plate 23, and the seal ring 24 constitutes a hermetically sealed cavity C. In addition, the sealing plate 23 is comprised by laminated bodies, such as Kov / Ni, for example.

  As shown in FIGS. 2 to 4, the piezoelectric vibrating reed 3 described above is accommodated in a cavity C of a hermetically sealed package 2. Specifically, the piezoelectric vibrating reed 3 includes a conductive bonding material (on the respective electrode pads 43 formed on the mounting portion 42 of the second substrate 32) in the cavity C. (Not shown). Thereby, in the cavity C, the piezoelectric vibrating reed 3 is surrounded by the second substrate 32 and the seal ring 24 and is supported in a floating state with respect to the bottom surface of the recess 21. In addition, as the conductive bonding material described above, a conductive adhesive, a metal bump, or the like can be used. The common point between the conductive adhesive and the metal bumps is that they have fluidity in the initial stage of bonding, and solidify in the later stage of bonding to develop bonding strength.

  In order to operate the piezoelectric vibrator 1 configured as described above, a predetermined voltage is applied to the external electrodes 35 and 36 (see FIG. 3). Then, a current flows through each excitation electrode, and an electric field is generated between each excitation electrode. The vibrating arms 12 and 13 vibrate at a predetermined resonance frequency, for example, in a direction (width direction W) approaching or separating from each other due to an inverse piezoelectric effect caused by an electric field generated between the excitation electrodes. The vibrations of the vibrating arm portions 12 and 13 are used as a time source, a timing source of control signals, a reference signal source, and the like.

As described above, in this embodiment, in plan view, the contour of the inner surface of the ring is larger than the contour of the inner surface of the frame portion, and the contour of the outer surface of the ring is smaller than the contour of the outer surface of the frame portion.
According to this configuration, the seal ring 24 easily fits within the width of the frame portion 41 in plan view. In this case, for example, even if the seal ring 24 is displaced from a desired position on the frame portion 41 due to the influence of a load or heat acting during welding of the sealing plate 23 and the seal ring 24, the inner surface of the frame portion or the frame portion. It can suppress that the seal ring 24 protrudes with respect to an outer surface. Therefore, during welding of the sealing plate 23 and the seal ring 24, it is possible to suppress a load from acting locally on the mounting substrate 22 via the seal ring 24, and it is possible to suppress damage to the mounting substrate 22 and the like.

Further, in this embodiment, the inner shape difference between the inner surface of the ring and the inner surface of the side wall and the outer shape difference between the outer surface of the ring and the outer surface of the side wall are equal to each other. On the other hand, the seal ring 24 can be reliably prevented from protruding.
Further, the width of the seal ring 24 is set to about 60% to 80% with respect to the width of the frame portion 41. Or it can suppress reliably that the seal ring 24 protrudes with respect to a frame part outer surface.

  And since the piezoelectric vibrator 1 of this embodiment is provided with the package 2 mentioned above, the fall of the vacuum degree in the cavity C accompanying damage to a mounting board | substrate etc. can be suppressed. As a result, the piezoelectric vibrator 1 having excellent vibration characteristics can be provided.

The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the present invention is applied to the so-called side arm type piezoelectric vibrating piece 3 in which the supporting arm portions 14 and 15 are arranged outside the vibrating arm portions 12 and 13 in the width direction W. However, the present invention is not limited to this. That is, the piezoelectric vibrating piece 3 only needs to have a pair of vibrating arm portions 12 and 13, for example, a so-called center arm type piezoelectric vibration in which one supporting arm portion is disposed between the pair of vibrating arm portions. A so-called tuning fork-type vibrating piece that does not include a piece or a supporting arm portion may be used.
Furthermore, as the piezoelectric vibrating piece, an AT vibrating piece that vibrates through thickness may be used.
Further, the electronic component sealed in the package 2 is not limited to the piezoelectric vibrating piece. For example, the package of the present invention may be applied to MEMS, crystal devices, optical devices, various sensors, batteries, and the like.

  In addition, in the range which does not deviate from the meaning of this invention, it is possible to replace suitably the component in the embodiment mentioned above by a known component, and you may combine each modification mentioned above suitably.

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric vibrator 2 ... Package 3 ... Piezoelectric vibration piece (electronic component)
21 ... concave part 22 ... mounting substrate 23 ... sealing plate (lid)
24 ... Seal ring (ring member)
41 ... Frame part (side wall part)

Claims (3)

A mounting substrate having a recess for accommodating an electronic component;
A ring member disposed on the side wall portion of the mounting substrate and surrounding the recess in a plan view as viewed from the thickness direction of the mounting substrate;
A lid joined on the ring member to close the recess,
In the plan view, the ring member has a contour of the inner surface of the ring larger than a contour of the inner surface of the side wall of the side wall, and a contour of the outer surface of the ring is smaller than a contour of the outer surface of the side wall of the side wall. Package characterized by being. Among the ring members, the inner surface of the ring is disposed closer to the outer surface of the sidewall portion than the inner surface of the sidewall portion, the outer surface of the ring is disposed closer to the inner surface of the sidewall portion than the outer surface of the sidewall portion,
The package according to claim 1, wherein a distance between the inner surface of the ring and the inner surface of the side wall and a distance between the outer surface of the ring and the outer surface of the side wall are equal to each other. A package according to claim 1 or claim 2;
A piezoelectric vibrator comprising: a piezoelectric vibrating piece housed in the recess.

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