JP2021175139A - Piezoelectric vibrator and manufacturing method thereof - Google Patents

Abstract

To provide a piezoelectric vibrator capable of suppressing noise generation and suppressing bad connection when the vibrator is mounted, and to provide a manufacturing method thereof.SOLUTION: A piezoelectric vibrator (1) comprises a piezoelectric vibration element (10), a base member (30) on which the piezoelectric vibration element (10) is mounted, and a lid member of a conductive material joined to the base member (30) across a joining member (50) of an insulating material and forming an internal space in which the piezoelectric vibration element (10) is arranged between itself and the base member (30). The base member (30) is provided with a feeding electrode to which the piezoelectric vibration element (10) is connected, and a ground electrode used for grounding. At least the ground electrode includes a side surface electrode (34c) provided in a side surface part of the base member (30), and is provided with a metal film (20) over the side surface electrode (34c) of the ground electrode, an external side surface of the joining member (50), and the lid member (40).SELECTED DRAWING: Figure 1

Description

The present invention relates to a piezoelectric vibrator and a method for manufacturing the same.

Oscillators are used in various electronic devices such as mobile communication terminals, communication base stations, and home appliances for applications such as timing devices, sensors, and oscillators. With the increasing functionality of electronic devices, inexpensive and high-performance vibrating elements are required.

In Patent Document 1, after joining a base member and a metal lid member via a resin joining member, the lid member is electrically connected to a grounding electrode with a conductive adhesive, and electromagnetic waves enter and exit. A crystal transducer that suppresses noise is disclosed.

In Patent Document 2, after joining the base member and the lid member of the insulating material with the joining member of the insulating material, a metal film covering substantially the entire upper surface of the lid member is electrically connected to the grounding electrode. A piezoelectric vibrator that suppresses noise due to the ingress and egress of electromagnetic waves is disclosed. The side electrode of the grounding electrode is provided only in the lower part of the side surface portion of the base member.

Japanese Unexamined Patent Publication No. 2016-001862 Japanese Unexamined Patent Publication No. 2011-160115

However, in the crystal oscillator described in Patent Document 1, when the amount of the resin bonding member is increased in order to improve the bonding strength between the base member and the lid member, the surplus bonding member becomes at least a part of the grounding electrode. May cause poor connection of the conductive adhesive. Further, when the surplus joining member covers at least a part of the side electrode, a conductive adhesive needs to cover a part of the side electrode in order to ground the lid member, and solder when mounting the crystal oscillator. The conductive adhesive may be decomposed by the heat of the above, resulting in poor connection.

In the piezoelectric vibrator described in Patent Document 2, if the metal film provided on the upper surface of the lid member has uneven thickness, the shielding effect of inhibiting the inflow and outflow of electromagnetic waves becomes insufficient, and noise may be generated. Further, when the base member is made of a single-layer substrate, it is difficult to provide the side electrode only in the lower portion of the side surface portion of the base member, which may increase the manufacturing cost.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a piezoelectric vibrator capable of suppressing connection failure at the time of mounting while suppressing generation of noise, and a method for manufacturing the same.

The piezoelectric vibrator according to one aspect of the present invention is joined by sandwiching a joining member of an insulating material between the piezoelectric vibrating element, the base member on which the piezoelectric vibrating element is mounted, and the base member, and the base member. A lid member made of a conductive material that forms an internal space in which a piezoelectric vibrating element is arranged is provided, and the base member includes a feeding electrode to which the piezoelectric vibrating element is connected and a grounding electrode used for grounding. The grounding electrode has a side electrode provided on the side surface of the base member, and a metal film is provided over the side electrode of the grounding electrode, the outer side surface of the joining member, and the lid member. ..

The method for manufacturing a piezoelectric vibrator according to one aspect of the present invention is to mount a piezoelectric vibrating element on a base member, sandwich a joining member of an insulating material between the base member, and join a lid member of a conductive material. Including forming an internal space in which the piezoelectric vibrating element is arranged between the base member and the base member, the base member includes a feeding electrode to which the piezoelectric vibrating element is connected and a grounding electrode used for grounding. Further, at least the grounding electrode has a side electrode provided on the side surface of the base member, and a metal film is formed over the side electrode of the grounding electrode, the outer side surface of the joining member, and the lid member. include.

According to the present invention, it is possible to provide a crystal oscillator capable of suppressing connection failure at the time of mounting while suppressing the generation of noise, and a method for manufacturing the same.

It is an exploded perspective view which shows schematic structure of the crystal oscillator which concerns on 1st Embodiment. It is a top view which shows schematic structure of the crystal oscillator which concerns on 1st Embodiment. It is sectional drawing which shows schematic the structure of the crystal oscillator which concerns on 1st Embodiment. It is a top view which shows roughly the structure of the base member and the crystal vibration element. It is a flowchart which shows roughly the manufacturing method of the crystal oscillator which concerns on 1st Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings of each embodiment are examples, and the dimensions and shapes of each part are schematic, and the technical scope of the present invention should not be limited to the embodiment.

<First Embodiment>
The configuration of the crystal oscillator 1 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is an exploded perspective view schematically showing the configuration of the crystal oscillator according to the first embodiment. FIG. 2 is a plan view schematically showing the configuration of the crystal oscillator according to the first embodiment. FIG. 3 is a cross-sectional view schematically showing the configuration of the crystal oscillator according to the first embodiment. FIG. 4 is a plan view schematically showing the configurations of the base member and the crystal vibrating element. Note that FIG. 3 is a cross-sectional view taken along the line III-III of the crystal oscillator 1 shown in FIG.

Each drawing is provided with a Cartesian coordinate system consisting of the X-axis, Y'axis and Z'axis for convenience to clarify the relationship between the drawings and to help understand the positional relationship of each member. Sometimes. The X-axis, Y'axis and Z'axis correspond to each other in the drawings. The X-axis, Y'axis, and Z'axis correspond to the crystallographic axes of the crystal piece 11 described later, respectively. The X-axis corresponds to the electric axis (polar axis) of the crystal, the Y-axis corresponds to the mechanical axis of the crystal, and the Z-axis corresponds to the optical axis of the crystal. The Y'axis and the Z'axis are axes obtained by rotating the Y axis and the Z axis around the X axis in the direction of the Y axis to the Z axis by 35 degrees 15 minutes ± 1 minute 30 seconds, respectively.

In the following description, the direction parallel to the X-axis is referred to as "X-axis direction", the direction parallel to the Y'axis is referred to as "Y'axis direction", and the direction parallel to the Z'axis is referred to as "Z'axis direction". Further, the direction of the tip of the arrow on the X-axis, Y'axis and Z'axis is called "+ (plus)", and the direction opposite to the arrow is called "-(minus)". For convenience, the + Y'axis direction is defined as an upward direction, and the −Y'axis direction is defined as a downward direction, but the vertical direction of the crystal oscillator 1 is not limited. For example, in the following description, the + Y'axis direction side of the crystal vibrating element 10 is the upper surface 11A, and the −Y'axis direction side is the lower surface 11B. It may be arranged so as to be located on the side.

The crystal oscillator 1 includes a crystal vibrating element 10, a metal film 20, a base member 30, a lid member 40, a joining member 50, and an insulating member 60. The crystal vibrating element 10 is provided between the base member 30 and the lid member 40. The base member 30 and the lid member 40 form a cage for accommodating the crystal vibrating element 10, and are overlapped along the Y'axis direction. For example, the base member 30 has a flat plate shape, and the lid member 40 has a bottomed opening for accommodating the crystal vibration element 10 on the base member 30 side. The crystal vibrating element 10 is mounted on the base member 30. If the crystal vibrating element 10 is housed in the cage, the shapes of the base member 30 and the lid member 40 are not limited to the above. For example, the base member 30 may have a bottomed opening on the lid member 40 side for accommodating a part of the crystal vibrating element 10. Further, the lid member 40 may have a flat plate shape. In the following description, the Y'axis direction, which is the direction in which the base member 30 and the lid member 40 overlap, is referred to as the "height direction".

First, the crystal vibrating element 10 will be described.
The crystal vibrating element 10 is an element that vibrates a crystal by a piezoelectric effect and converts electrical energy and mechanical energy. The crystal vibrating element 10 includes a flaky crystal piece 11, a first excitation electrode 14a and a second excitation electrode 14b constituting a pair of excitation electrodes, and a first extraction electrode 15a and a second extraction electrode forming a pair of extraction electrodes. It includes an electrode 15b, and a first connection electrode 16a and a second connection electrode 16b forming a pair of connection electrodes.

The crystal piece 11 has an upper surface 11A and a lower surface 11B facing each other. The upper surface 11A is located on the side opposite to the side facing the base member 30, that is, the side facing the top wall portion 41 of the lid member 40 described later. The lower surface 11B is located on the side facing the base member 30.

The crystal piece 11 is, for example, an AT-cut type crystal piece. The AT-cut type crystal piece 11 is a plane parallel to a plane specified by the X-axis and the Z'axis in a Cartesian coordinate system consisting of an X-axis, a Y'axis, and a Z'axis that intersect each other (hereinafter, "XZ". It is called a'plane'. The same applies to a plane specified by another axis.) Is the main surface, and is formed so that the direction parallel to the Y'axis is the thickness. For example, the AT-cut type crystal piece 11 is formed by etching a crystal substrate (for example, a crystal wafer) obtained by cutting and polishing a crystal of synthetic quartz crystal.

The crystal vibrating element 10 using the AT-cut type crystal piece 11 has high frequency stability in a wide temperature range. In the AT-cut type crystal vibration element 10, the thick slip vibration mode (Thickness Shear Vibration Mode) is used as the main vibration. The rotation angles of the Y'axis and the Z'axis of the AT-cut type crystal piece 11 may be tilted in the range of 35 degrees 15 minutes to −5 degrees or more and 15 degrees or less. As the cut angle of the crystal piece 11, a different cut other than the AT cut may be applied. For example, BT cut, GT cut, SC cut and the like may be applied. Further, the crystal vibrating element may be a tuning fork type crystal vibrating element using a crystal piece having a cut angle called a Z plate.

The AT-cut type crystal piece 11 is parallel to the long side direction in which the long side parallel to the X-axis direction extends, the short side direction in which the short side parallel to the Z'axis direction extends, and the Y'axis direction. It is a plate shape having a thickness direction in which a large thickness extends. When the upper surface 11A of the crystal piece 11 is viewed in a plane, the plane shape of the crystal piece 11 is rectangular.

The planar shape of the crystal piece 11 when the upper surface 11A is viewed in a plan view is not limited to a rectangular shape. The planar shape of the crystal piece 11 may be a polygonal shape, a circular shape, an elliptical shape, or a combination thereof. The planar shape of the crystal piece 11 may be a tuning fork shape. In other words, the crystal piece 11 may have a base and a vibrating arm extending in parallel from the base. A slit may be formed in the crystal piece 11 for the purpose of suppressing vibration leakage and stress propagation.

The crystal piece 11 is not limited to a flat plate shape, and may have a mesa-shaped structure or an inverted mesa-shaped structure. In this case, the crystal piece 11 has a tapered shape in which the thickness changes continuously, a staircase shape in which the change in thickness changes discontinuously, a convex shape in which the amount of change in thickness continuously changes, or a convex shape in which the amount of change in thickness does not change. It may have a bevel shape that changes continuously.

The first excitation electrode 14a is provided on the upper surface 11A side of the crystal piece 11, and the second excitation electrode 14b is provided on the lower surface 11B side of the crystal piece 11. In other words, the first excitation electrode 14a is provided on the main surface of the crystal piece 11 on the lid member 40 side, and the second excitation electrode 14b is provided on the main surface of the crystal piece 11 on the base member 30 side. The first excitation electrode 14a and the second excitation electrode 14b face each other with the crystal piece 11 interposed therebetween. When the upper surface 11A of the crystal piece 11 is viewed in a plan view, the first excitation electrode 14a and the second excitation electrode 14b each have a rectangular shape, and are arranged so that substantially the entire surface of the crystal piece 11 overlaps with each other.

The planar shapes of the first excitation electrode 14a and the second excitation electrode 14b when the upper surface 11A of the crystal piece 11 is viewed in a plan view are not limited to a rectangular shape. The planar shape of the first excitation electrode 14a and the second excitation electrode 14b may be a polygonal shape, a circular shape, an elliptical shape, or a combination thereof.

The first extraction electrode 15a is provided on the upper surface 11A side of the crystal piece 11, and the second extraction electrode 15b is provided on the lower surface 11B side of the crystal piece 11. The first extraction electrode 15a electrically connects the first excitation electrode 14a and the first connection electrode 16a. The second extraction electrode 15b electrically connects the second excitation electrode 14b and the second connection electrode 16b. For the purpose of reducing stray capacitance, it is desirable that the first extraction electrode 15a and the second extraction electrode 15b are separated from each other when the upper surface 11A of the crystal piece 11 is viewed in a plan view. For example, the first extraction electrode 15a is provided in the + Z'axis direction when viewed from the second extraction electrode 15b.

The first connection electrode 16a and the second connection electrode 16b are electrodes for electrically connecting the first excitation electrode 14a and the second excitation electrode 14b to the base member 30, respectively, and are located on the lower surface 11B side of the crystal piece 11. It is provided. The first connection electrode 16a is provided at a corner formed by an end portion of the crystal piece 11 on the −X axis direction side and an end portion on the + Z ′ axis direction side, and the second connection electrode 16b is the crystal piece 11 of the crystal piece 11. It is provided at a corner formed by an end portion on the −X axis direction side and an end portion on the −Z ′ axis direction side.

One of the electrode groups including the first excitation electrode 14a, the first extraction electrode 15a, and the first connection electrode 16a is formed continuously with each other, for example, integrally with each other. Similarly, the other electrode group including the second excitation electrode 14b, the second extraction electrode 15b, and the second connection electrode 16b is also formed continuously with each other, for example, integrally with each other. As described above, the crystal vibrating element 10 is provided with a pair of electrodes. The pair of electrodes of the crystal vibrating element 10 has, for example, a multi-layer structure, and the base layer and the outermost layer are laminated in this order. The base layer is a layer that comes into contact with the crystal piece 11, and is provided with a material having good adhesion to the crystal piece 11. The outermost layer is a layer located on the outermost surface of the pair of electrodes, and is provided with a material having good chemical stability. According to this, peeling and oxidation of a pair of electrodes can be suppressed, and a highly reliable crystal vibrating element 10 can be provided. The base layer contains, for example, chromium (Cr), and the outermost layer contains, for example, gold (Au).

The materials constituting the pair of electrodes of the crystal vibrating element 10 are not limited to Cr and Au, and are, for example, titanium (Ti), molybdenum (Mo), aluminum (Al), nickel (Ni), and indium (In). , Palladium (Pd), silver (Ag), copper (Cu), tin (Sn), iron (Fe) and other metallic materials may be contained. The pair of electrodes may contain a conductive ceramic, a conductive resin, a semiconductor, or the like.

Next, the base member 30 will be described.
The base member 30 holds the crystal vibrating element 10 in an excitable manner. The base member 30 includes a flat plate-shaped substrate 31, a first electrode pad 33a and a second electrode pad 33b forming a pair of electrode pads, a top electrode 33c, a first side electrode 34a, a second side electrode 34b, and a second electrode member 30. It includes three side electrode 34c, a fourth side electrode 34d, a first external electrode 35a, a second external electrode 35b, a third external electrode 35c, a fourth external electrode 35d, and a protective film 39.

The substrate 31 has an upper surface 31A and a lower surface 31B facing each other. The upper surface 31A and the lower surface 31B correspond to a pair of main surfaces of the substrate 31. The upper surface 31A corresponds to the first surface of the base member 30, and the lower surface 31B corresponds to the second surface of the base member 30. The upper surface 31A is located on the side facing the crystal vibrating element 10 and the lid member 40, and corresponds to a mounting surface on which the crystal vibrating element 10 is mounted. The lower surface 31B is located on the side facing the circuit board when the crystal oscillator 1 is mounted on an external circuit board, and corresponds to a mounting surface to which the circuit board is connected. The substrate 31 is a sintered material such as an insulating ceramic (alumina). From the viewpoint of suppressing the generation of thermal stress, the substrate 31 is preferably made of a heat-resistant material. From the viewpoint of suppressing the stress applied to the crystal vibrating element 10 by the thermal history, the substrate 31 may be provided by a material having a coefficient of thermal expansion close to that of the crystal piece 11, or may be provided by, for example, quartz. Further, from the viewpoint of suppressing damage to the substrate 31 due to thermal stress, the substrate 31 may be provided with a material having a coefficient of thermal expansion close to that of the lid member 40.

When the upper surface 31A is viewed in a plan view, the substrate 31 has a pair of long sides extending in the X-axis direction and facing each other in the Z'axis direction, and a pair of short sides extending in the Z'axis direction and facing each other in the X-axis direction. Have. Fan-shaped recesses are provided at the four corners of the substrate 31. This recess is formed by dividing a through hole penetrating the substrate 31 from the upper surface 31A to the lower surface 31B.

The first electrode pad 33a and the second electrode pad 33b are provided on the upper surface 31A of the substrate 31. The first electrode pad 33a and the second electrode pad 33b are terminals for electrically connecting the crystal vibrating element 10 to the base member 30. From the viewpoint of suppressing a decrease in reliability due to oxidation, it is desirable that the outermost surfaces of the first electrode pad 33a and the second electrode pad 33b each contain gold, and it is more desirable that the outermost surfaces thereof are composed of almost only gold. For example, the first electrode pad 33a and the second electrode pad 33b may have a laminated structure having a base layer for improving adhesion to the substrate 31 and an outermost surface containing gold and suppressing oxidation.

The top electrode 33c is an electrode that is electrically connected to the lid member 40. The upper surface electrode 33c is provided at the corners of the base member 30 on the + X axis direction side and the −Z ′ axis direction side, and is located on the outermost surface of the base member 30 on the lid member 40 side.

The first side surface electrodes 34a to the fourth side surface electrodes 34d are provided on the side surface portions of the base member 30. Specifically, it extends over a region between the upper surface 31A and the lower surface 31B of the recess provided at the corner of the substrate 31. In other words, the first side surface electrodes 34a to the fourth side surface electrodes 34d are provided from the end portion of the side surface portion on the upper surface 31A side to the end portion on the lower surface 31B side, and cover the recess of the substrate 31. Each of the first side electrode 34a to the fourth side electrode 34d corresponds to a casting electrode. The first side surface electrode 34a is provided in a recess provided at a corner of the base member 30 on the −X axis direction side and the + Z ′ axis direction side. The second side surface electrode 34b is provided in a concave portion provided on the diagonal of the first side surface electrode 43a, that is, at the corners of the base member 30 on the + X axis direction side and the −Z ′ axis direction side. The third side electrode 34c is provided in a recess provided at a corner of the base member 30 on the + X axis direction side and the + Z'axis direction side. The fourth side electrode 34d is provided in a concave portion provided on the diagonal of the third side electrode 34c, that is, at the corners of the base member 30 on the −X axis direction side and the −Z ′ axis direction side.

The first side surface electrode 34a is electrically connected to the first electrode pad 33a via the wiring electrode provided on the upper surface 31A, and the second side surface electrode 34b is connected to the second side electrode 34b via the wiring electrode provided on the upper surface 31A. It is electrically connected to the electrode pad 33b. The third side surface electrode 34c is continuously provided from the top surface electrode 33c and is electrically connected to the top surface electrode 33c. The first side surface electrode 34a, the first electrode pad 33a, and the wiring electrode connecting them correspond to a feeding electrode to which the crystal vibration element 10 is connected. The second side surface electrode 34b, the second electrode pad 33b, and the wiring electrode connecting them also correspond to the feeding electrode. The third side electrode 34c and the top electrode 33c correspond to grounding electrodes used for grounding the lid member 40.

The first external electrodes 35a to the fourth external electrodes 35d are electrodes for mounting the crystal oscillator 1 on an external circuit board by soldering or the like. The first external electrode 35a to the fourth external electrode 35d are provided on the lower surface 31B of the substrate 31. The first external electrode 35a is provided at a corner of the base member 30 on the −X axis direction side and the + Z ′ axis direction side, and is electrically connected to the first side surface electrode 34a. The first external electrode 35a is provided at the corners of the base member 30 on the + X axis direction side and the −Z ′ axis direction side, and is electrically connected to the second side surface electrode 34b. The third external electrode 35c is provided at the corners of the base member 30 on the + X axis direction side and the + Z'axis direction side, and is electrically connected to the third side surface electrode 34c. The fourth external electrode 35d is provided at the corners of the base member 30 on the −X axis direction side and the −Z ′ axis direction side, and is electrically connected to the fourth side surface electrode 34d. The first external electrode 35a and the second external electrode 35b are used to supply an electric signal to the pair of feeding electrodes. The third external electrode 35c is used to ground the grounding electrode. The fourth external electrode 35d is a dummy electrode to which an electric signal or the like is not input / output. The fourth external electrode 35d may be used for grounding the lid member 40 together with the third external electrode 35c, or may be omitted.

The protective film 39 is provided on the side of the base member 30 facing the lid member 40 and in a region in contact with the joining member 50. The protective film 39 covers a part of the feeding electrode and electrically insulates the feeding electrode and the lid member 40. Specifically, the protective film 39 covers the wiring electrode connecting the first side surface electrode 34a and the first electrode pad 33a, and covers the wiring electrode connecting the second side surface electrode 34b and the second electrode pad 33b. There is. The protective film 39 is provided in the outer region of the upper surface electrode 33c, and the upper surface electrode 33c is exposed from the protective film 39. The protective film 39 may cover the upper surface electrode 33c.

The base member 30 includes a first conductive holding member 36a and a second conductive holding member 36b that form a pair of conductive holding members. The first conductive holding member 36a and the second conductive holding member 36b hold the crystal vibrating element 10 at intervals from the base member 30 and the lid member 40. The first conductive holding member 36a and the second conductive holding member 36b electrically connect the crystal vibrating element 10 and the base member 30. Specifically, the first conductive holding member 36a electrically connects the first electrode pad 33a and the first connecting electrode 16a, and the second conductive holding member 36b electrically connects the second electrode pad 33b and the second connecting electrode. It is electrically connected to 16b.

The first conductive holding member 36a and the second conductive holding member 36b are cured products of a conductive adhesive containing a thermosetting resin, a photocurable resin, and the like, and the first conductive holding member 36a and the second conductive. The main component of the property-retaining member 36b is, for example, a silicone resin. The first conductive holding member 36a and the second conductive holding member 36b contain conductive particles, and as the conductive particles, for example, metal particles containing silver (Ag) are used. The first conductive holding member 36a joins the first electrode pad 33a and the first connecting electrode 16a, and the second conductive holding member 36b joins the second electrode pad 33b and the second connecting electrode 16b.

The main components of the first conductive holding member 36a and the second conductive holding member 36b are not limited to silicone resins as long as they are curable resins, and may be, for example, epoxy resins or acrylic resins. Further, the imparting of conductivity to the first conductive holding member 36a and the second conductive holding member 36b is not limited to that by silver particles, and other metals, conductive ceramics, conductive organic materials, etc. It may be due to. The main components of the first conductive holding member 36a and the second conductive holding member 36b may be a conductive polymer.

Any additive may be contained in the resin composition of the first conductive holding member 36a and the second conductive holding member 36b. The additive is, for example, a tackifier, a filler, a thickener, a sensitizer, an antiaging agent, an antifoaming agent, etc. for the purpose of improving the workability and storage stability of the conductive adhesive. Further, a filler may be added for the purpose of increasing the strength of the cured product or for maintaining the distance between the base member 30 and the crystal vibrating element 10.

Next, the lid member 40 will be described.
The lid member 40 is joined to the base member 30. The lid member 40 forms an internal space for accommodating the crystal vibrating element 10 with the base member 30. The lid member 40 has a recess 49 that opens on the side of the base member 30, and the internal space in the present embodiment corresponds to the space inside the recess 49. The recess 49 is liquidtightly sealed. The material of the lid member 40 is preferably a conductive material, and more preferably a highly airtight metal material. Since the lid member 40 is made of a conductive material, the lid member 40 is provided with an electromagnetic shield function that reduces the ingress and egress of electromagnetic waves into the internal space. From the viewpoint of suppressing the generation of thermal stress, the material of the lid member 40 is preferably a material having a coefficient of thermal expansion close to that of the substrate 31, for example, the coefficient of thermal expansion near room temperature is in a wide temperature range of glass or ceramic. It is a matching Fe—Ni—Co based alloy. The elastic modulus of the lid member 40 is preferably smaller than the elastic modulus of the substrate 31. According to this, the lid member 40 absorbs the impact from the outside. Specifically, when a small external stress is applied to the lid member 40, the lid member 40 is elastically deformed, and when a relatively large external stress is applied to the lid member 40, the lid member 40 is plastically deformed. By deforming the lid member 40 in this way, damage to the base member 30 due to external stress is suppressed.

The lid member 40 has a flat top wall portion 41 and a side wall portion 42 connected to the outer edge of the top wall portion 41 and extending along the height direction. The top wall portion 41 and the side wall portion 42 are integrally formed. The recess 49 of the lid member 40 is formed by the top wall portion 41 and the side wall portion 42. Specifically, the top wall portion 41 extends along the upper surface 31A of the substrate 31 and faces the base member 30 with the crystal vibrating element 10 interposed therebetween in the height direction. Further, the side wall portion 42 extends from the top wall portion 41 toward the base member 30, and surrounds the crystal vibrating element 10 in a direction parallel to the upper surface 31A of the base 31. The lid member 40 may further have a flange portion that is connected to the tip of the side wall portion 42 on the base member 30 side and extends outward along the upper surface 31A of the substrate 31.

The lid member 40 has an inner surface located on the side of the recess 49 and an outer surface on the opposite side of the recess 49 and exposed to the outside. The inner surface is the side of the top wall portion 41 and the side wall portion 42 facing the crystal oscillator 10, and the outer surface is the side of the top wall portion 41 and the side wall portion 42 opposite to the side facing the crystal oscillator 10. The lid member 40 further has a facing surface facing the base member 30. The facing surface is a surface extending parallel to the upper surface 31A of the base member 30 at the tip of the side wall portion 42 of the base member 30, and can be expanded by providing a flange portion.

The planar shape of the lid member 40 when viewed in a plane from the normal direction of the main surface is, for example, a substantially rectangular shape. The planar shape of the lid member 40 is not limited to the above, and may be a polygonal shape, a circular shape, an elliptical shape, or a combination thereof.

Next, the insulating member 60 will be described.
It is provided in a frame shape along the tip of the side wall portion 42 of the lid member 40. Specifically, it covers the facing surface of the side wall portion 42, and covers a part of the inner surface and the outer surface. The insulating member 60 increases the contact area with the joining member 50 to improve the joining strength. Further, the insulating member 60 suppresses the fluctuation of the gap between the base member 30 and the lid member 40 due to the fluctuation of the facing surface due to the waviness of the lid member 40, and brings the contact surface with the joining member 50 closer to the same plane. , Suppresses partial deterioration of bonding strength and sealing performance. The insulating member 60 is provided between the protective film 39 and the lid member 40, and is provided between the power feeding electrode and the side wall portion 42, and between the grounding electrode and the side wall portion 42. ..

Next, the joining member 50 will be described.
The joining member 50 is provided over the entire circumference of each outer edge portion of the base member 30 and the lid member 40, and has a rectangular frame shape. When the upper surface 31A of the base member 30 is viewed in a plan view, the first electrode pad 33a and the second electrode pad 33b are arranged inside the joining member 50, and the joining member 50 is provided so as to surround the crystal vibration element 10. ing. The joining member 50 joins the base member 30 and the lid member 40, and seals the recess 49 corresponding to the internal space. Specifically, the joining member 50 joins the protective film 39 and the insulating member 60, and joins the top electrode 33c and the insulating member 60. From the viewpoint of suppressing fluctuations in the frequency characteristics of the crystal vibrating element 10, it is desirable that the material of the joining member 50 has low moisture permeability, and more preferably low gas permeability. The joining member 50 is, for example, a resin-based adhesive containing a thermosetting resin such as an epoxy-based resin.

The joining member 50 may be provided with an inorganic adhesive such as a silicon-based adhesive containing water glass or the like or a calcium-based adhesive containing cement or the like. The material of the joining member 50 may be provided by an organic adhesive containing an epoxy-based, vinyl-based, acrylic-based, urethane-based, imide-based or silicone-based thermosetting resin or photocurable resin. The base member 30 and the lid member 40 may be joined by seam welding.

Next, the metal film 20 will be described.
The metal film 20 electrically connects the grounding electrode and the lid member 40. The metal film 20 is provided over the third side electrode 34c constituting the grounding electrode, the outer side surface of the joining member 50, the outer side surface of the insulating member 60, and the outer surface of the lid member 40. The metal film 20 covers the region from the end of the third side electrode 34c on the upper surface 31A side to the lower surface 31B. The metal film 20 is provided from the side wall portion 42 to the top wall portion 41. For example, when the lid member 40 is viewed in a plan view, the metal film 20 is provided in a fan shape at the corners of the lid member 40 and the base member 30, and is provided outside the region of the lid member 40 that overlaps with the crystal vibration element 10. .. The thickness of the metal film 20 is about 0.5 to 10 μm.

The shape and position of the metal film 20 are not limited to the above. The metal film 20 may be provided in a band shape, or may be provided in a region overlapping the crystal vibrating element 10. Further, the metal film 20 provided on the lid member 40 may not be provided on the top wall portion 41 but may be provided only on the side wall portion 42.

Next, a method of manufacturing the crystal oscillator 1 will be described with reference to FIG. FIG. 5 is a flowchart schematically showing a method for manufacturing a crystal oscillator according to the first embodiment.

First, the metal plate is processed into a concave shape (S11).
A metal plate made of a Fe—Ni—Co alloy is prepared. The top wall portion and the side wall portion of the lid member are formed by drawing processing in which the metal plate is deformed by a pressing method.

Next, an insulating member is formed at the tip of the side wall portion (S13).
Apply a resin adhesive to the side wall and let it dry. At this time, the amount of the resin adhesive applied is changed according to the height from the connection portion with the top wall portion to the tip. A larger amount of resin-based adhesive than the tip of the side wall portion having a large height is applied to the tip of the side wall portion having a small height so that the contact surface with the joining member provided by the insulating member is brought close to the same plane.

Next, an electrode is provided on the substrate (S21).
A metal film is patterned on an alumina green sheet, and the metal film is sintered together with the green sheet. As a result, the substrate is formed from the green sheet, and the feeding electrode, the grounding electrode, and the external electrode are formed from the metal film. For metal films, for example, various printing methods (screen printing, inkjet printing, gravure printing, flexographic printing, etc.), various coating methods (cast, dispense, etc.), and various wet plating methods (electroless plating, hot-dip plating, etc.) It is formed by a wet process such as electroplating).

The substrate may be formed of a wafer cut from an ingot. The metal film may be formed by a dry process exemplifying various vapor deposition methods such as PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition). At least a part of the electrodes of the base member may be formed after sintering the green sheet.

Next, a part of the electrode is covered with a protective film (S23).
The protective film is formed by, for example, a solder resist. The protective film may be formed of a suitable thermosetting resin or photocurable resin.

Next, a crystal vibrating element is mounted (S25).
A conductive adhesive paste containing a composition of a thermosetting resin is applied onto the electrode pads of the base member. Next, the crystal vibrating element 10 is placed on the conductive adhesive paste, and the conductive adhesive paste is heated and cured.

Before placing the crystal vibrating element on the conductive adhesive paste, preheating may be performed to adjust the viscosity of the conductive adhesive paste. Further, the resin composition of the conductive adhesive paste is not limited to the composition of the thermosetting resin, and may include the composition of the photocurable resin. In this case, the step S23 may include a step of irradiating the conductive adhesive paste with light such as ultraviolet rays.

Next, the base member and the lid member are joined (S31).
The lid member is stored in a tray so that the inner surface is exposed, and an adhesive paste containing a composition of a thermosetting resin is applied to the tip of the side wall portion of the lid member. Next, the base member is stored in the tray and stacked on the lid member. Next, the adhesive paste is heated and cured to seal the internal space containing the crystal vibrating element.

Next, a metal film is formed (S33).
The metal film is formed by a sputtering method or a vacuum vapor deposition method.

The order of the steps S11 to S13 from the formation of the lid member to the formation of the insulating member and the steps S21 to S25 from the preparation of the base member to the mounting of the crystal vibration element is not limited to the above. Steps S11 to S13 may be carried out after steps S21 to 25.

As described above, in the present embodiment, the base member 30 and the lid member 40 made of the conductive material are joined by the joining member 50 made of the insulating material, the side electrode 34c of the grounding electrode, the outer side surface of the joining member 50, and the outer side surface of the joining member 50. The metal film 20 provided over the lid member 40 electrically connects the lid member 40 to the ground electrode.
According to this, since the lid member 40 is grounded, a shielding effect of blocking the ingress and egress of electromagnetic waves can be obtained, and the generation of noise is suppressed. Further, since the conductive member that electrically connects the grounding electrode and the lid member 40 is the metal film 20, it is caused by the decomposition of the conductive member due to the heat of the solder when the crystal vibrating element is mounted on the external circuit board. It is possible to suppress the occurrence of poor connection.

In the plan view of the lid member 40, the metal film 20 is provided outside the region of the lid member 40 that overlaps with the crystal vibration element 10.
In a plan view of the lid member 40, the metal film 20 is provided at the corners of the lid member 40 and the base member 30.
Since the lid member 40 is a conductive material, if the metal film 20 comes into contact with a part of the lid member 40, the entire lid member 40 is grounded, so that the shielding effect is partially reduced due to the uneven thickness of the metal film 20. Is not generated, and a sufficient shielding effect can be obtained. Compared with the configuration in which the metal film 20 is provided on substantially the entire upper surface so as to cover the lid member 40, the consumption of the raw material of the metal film 20 can be reduced.

The lid member 40 has a top wall portion 41 and a side wall portion 42 integrally formed of metal.
According to this, even if the lid member 40 is made of a ductile material, the lid member 40 having the shape according to the present embodiment can be easily formed by drawing processing by a press method or the like. Further, when an impact is applied to the crystal unit 1 due to dropping or the like, the external stress can be relaxed by the deformation of the lid member 40.

An insulating member 60 is provided on the side wall portion 42 of the lid member 40 facing the base member 30.
According to this, the area of the contact surface with the joining member 50 on the lid member 40 side can be expanded. Further, by suppressing the fluctuation of the gap between the base member 30 and the lid member 40 due to the fluctuation of the facing surface due to the undulation of the lid member 40, the contact surface with the joining member 50 on the lid member 40 side is brought closer to the same plane. , Suppresses partial deterioration of bonding strength and sealing performance.

The side electrode 34c is provided on the side surface of the base member 30 and extends over a region between the upper surface 31A and the lower surface 31B.
According to this, the area of the contact surface with the joining member 50 can be expanded.

The side electrode 34c covers the side electrode 34c up to a region extending to the lower surface 31B of the base member 30.
According to this, the contact area between the grounding electrode and the metal film can be expanded without worrying about mounting defects due to thermal decomposition of the conductive member for grounding the lid member 40.

The metal film 20 is formed by a sputtering method or a vacuum vapor deposition method.

Hereinafter, a part or all of the embodiments of the present invention will be added, and the effects thereof will be described. The present invention is not limited to the following appendices.

According to one aspect of the present invention, the crystal vibrating element, the base member on which the crystal vibrating element is mounted, and the base member are joined by sandwiching a joining member of an insulating material, and the crystal is formed between the base member and the base member. A lid member made of a conductive material that forms an internal space in which the vibrating element is arranged is provided, and the base member is provided with a power feeding electrode to which the crystal vibrating element is connected and a grounding electrode used for grounding. At least the ground electrode has a side electrode provided on the side surface of the base member, and a metal film is provided over the side electrode of the ground electrode, the outer side surface of the joining member, and the lid member. The child is provided.
According to this, since the lid member is grounded, a shielding effect of blocking the ingress and egress of electromagnetic waves can be obtained, and the generation of noise is suppressed. Further, since the conductive member that electrically connects the grounding electrode and the lid member is a metal film, the connection caused by the decomposition of the conductive member due to the heat of the solder when the crystal vibrating element is mounted on the external circuit board. The occurrence of defects can be suppressed.

As one aspect, in a plan view of the lid member, the metal film is provided outside the region of the lid member that overlaps the crystal oscillator.
As one aspect, the base member and the lid member are each formed in a rectangular shape, and the metal film is provided at the corners of the lid member and the base member in a plan view of the lid member.
According to this, since the lid member is a conductive material, if the metal film comes into contact with a part of the lid member, the entire lid member is grounded, so that the shielding effect is partially reduced due to the uneven thickness of the metal film. Is not generated, and a sufficient shielding effect can be obtained. Compared with the configuration in which the metal film is provided on substantially the entire upper surface so as to cover the lid member, the consumption of the raw material of the metal film can be reduced.

In one aspect, the lid member has a top wall portion and a side wall portion extending from the outer edge of the top wall portion toward the base member, and the top wall portion and the side wall portion are integrally formed of metal.
According to this, even if the lid member 40 is made of a ductile material, the lid member 40 having the shape according to the present embodiment can be easily formed by drawing processing by a press method or the like. Further, when an impact is applied to the crystal unit 1 due to dropping or the like, the external stress can be relaxed by the deformation of the lid member 40.

As one aspect, an insulating member is provided on the side wall of the lid member facing the base member.
According to this, the area of the contact surface with the joining member on the lid member side can be expanded. Further, by suppressing the fluctuation of the gap between the base member and the lid member due to the fluctuation of the facing surface due to the swell of the lid member and bringing the contact surface with the joining member on the lid member side close to the same plane, partial joining is performed. Suppresses deterioration of strength and sealing performance.

In one aspect, the base member has a first surface on the side on which the crystal vibrating element is mounted and a second surface on the side opposite to the first surface, and the side electrode has a first surface to a second surface. It extends over the area between.
According to this, the area of the contact surface between the side electrode and the joining member can be expanded.

In one aspect, the metal film covers the side electrodes up to the region up to the second surface of the base member.
According to this, the contact area between the grounding electrode and the metal film can be expanded without worrying about mounting defects due to thermal decomposition of the conductive member for grounding the lid member.

According to another aspect of the present invention, the crystal oscillator is mounted on the base member, and the lid member of the conductive material is joined by sandwiching the joining member of the insulating material between the base member and the base member. The base member is provided with a power feeding electrode to which the crystal oscillator is connected and a grounding electrode used for grounding, including forming an internal space in which the crystal oscillator is arranged between the two. The ground electrode has a side electrode provided on the side surface of the base member, further comprising forming a metal film over the side electrode of the ground electrode, the outer side surface of the joining member, and the lid member. A method of manufacturing a child can be provided.
As one aspect, forming the metal film includes forming the metal film by a sputtering method or a vacuum vapor deposition method.

The embodiment according to the present invention is not limited to the crystal unit, and can be applied to the piezoelectric unit. An example of a piezoelectric vibrator (Piezoelectric Resonator Unit) is a crystal oscillator (Quartz Crystal Resnotor Unit) provided with a crystal vibrating element (Quartz Crystal Resonator). The crystal vibrating element uses a crystal piece (Quartz Crystal Element) as a piezoelectric piece excited by the piezoelectric effect, and the piezoelectric piece is an arbitrary such as a piezoelectric single crystal, a piezoelectric ceramic, a piezoelectric thin film, or a piezoelectric polymer film. It may be formed by the piezoelectric material of. As an example, the piezoelectric single crystal can include lithium niobate (LiNbO ₃ ). Similarly, the piezoelectric ceramic is barium titanate (BaTiO _3), lead titanate (PbTiO _3), lead zirconate titanate _{(Pb (Zr x Ti 1-} x) O3; PZT), aluminum nitride (AlN), niobium Lithium acid (LiNbO ₃ ), lithium metaniobate (LiNb ₂ O ₆ ), bismuth titanate (Bi ₄ Ti ₃ O ₁₂ ), lithium tantalate (LiTaO ₃ ), lithium tetraborate (Li ₂ B ₄ O ₇ ), Langasite (La ₃ Ga ₅ SiO ₁₄ ), tantalate pentoxide (Ta ₂ O ₅ ), and the like can be mentioned. Examples of the piezoelectric thin film include those obtained by forming the above-mentioned piezoelectric ceramic on a substrate such as quartz or sapphire by a sputtering method or the like. Examples of the piezoelectric polymer film include polylactic acid (PLA), polyvinylidene fluoride (PVDF), and vinylidene fluoride / ethylene trifluoride (VDF / TrFE) copolymer. The above-mentioned various piezoelectric materials may be used by being laminated with each other, or may be laminated with another member.

The embodiment according to the present invention can be appropriately applied without particular limitation as long as it is a device that converts electromechanical energy by a piezoelectric effect, such as a timing device, a sounding device, an oscillator, and a load sensor.

As described above, according to one aspect of the present invention, it is possible to provide a piezoelectric vibrator capable of suppressing connection failure at the time of mounting while suppressing generation of noise, and a method for manufacturing the piezoelectric vibrator.

It should be noted that the embodiments described above are for facilitating the understanding of the present invention, and are not for limiting and interpreting the present invention. The present invention can be modified / improved without departing from the spirit thereof, and the present invention also includes an equivalent thereof. That is, those skilled in the art with appropriate design changes to each embodiment are also included in the scope of the present invention as long as they have the features of the present invention. For example, each element included in each embodiment and its arrangement, material, condition, shape, size, and the like are not limited to those exemplified, and can be changed as appropriate. In addition, the elements included in each embodiment can be combined as much as technically possible, and the combination thereof is also included in the scope of the present invention as long as the features of the present invention are included.

1 ... Crystal oscillator,
10 ... Crystal oscillator,
20 ... Metal film,
30 ... Base member,
31 ... Hypokeimenon,
33a, 33b ... Electrode pads,
34a-34d ... Side electrodes,
35a-35d ... External electrodes,
40 ... Closure member,
41 ... Top wall,
42 ... Side wall,
50 ... Joining member,
60 ... Insulation member,

Claims (9)

Piezoelectric vibrating element and
The base member on which the piezoelectric vibration element is mounted and
A lid member made of a conductive material which is joined by sandwiching a joining member of an insulating material between the base member and forming an internal space in which the piezoelectric vibrating element is arranged between the base member and the lid member.
With
The base member is provided with a power feeding electrode to which the piezoelectric vibration element is connected and a grounding electrode used for grounding, and at least the grounding electrode is a side electrode provided on a side surface portion of the base member. Have and
A piezoelectric vibrator in which a metal film is provided over the side electrode of the grounding electrode, the outer side surface of the joining member, and the lid member. In a plan view of the lid member, the metal film is provided outside the region of the lid member that overlaps with the piezoelectric vibrating element.
The piezoelectric vibrator according to claim 1. The base member and the lid member are each formed in a rectangular shape.
In a plan view of the lid member, the metal film is provided at a corner portion of the lid member and the base member.
The piezoelectric vibrator according to claim 1 or 2. The lid member has a top wall portion and a side wall portion extending from the outer edge of the top wall portion toward the base member.
The top wall portion and the side wall portion are integrally formed of metal.
The piezoelectric vibrator according to any one of claims 1 to 3. An insulating member is provided on the side wall of the lid member facing the base member.
The piezoelectric vibrator according to claim 4. The base member has a first surface on the side on which the piezoelectric vibrating element is mounted and a second surface on the side opposite to the first surface.
The side electrode extends over a region between the first surface and the second surface.
The piezoelectric vibrator according to any one of claims 1 to 5. The metal film covers the side electrode up to a region of the base member up to the second surface.
The piezoelectric vibrator according to claim 6. Mounting the piezoelectric vibrating element on the base member,
A joint member made of an insulating material is sandwiched between the base member and a lid member made of a conductive material, and an internal space in which the piezoelectric vibrating element is arranged is formed between the base member and the lid member.
Including
The base member is provided with a power feeding electrode to which the piezoelectric vibration element is connected and a grounding electrode used for grounding, and at least the grounding electrode is a side electrode provided on a side surface portion of the base member. Have and
A method for manufacturing a piezoelectric vibrator, further comprising forming a metal film over the side electrode of the grounding electrode, the outer side surface of the joining member, and the lid member. The method for manufacturing a piezoelectric vibrator according to claim 8, wherein forming the metal film includes forming the metal film by a sputtering method or a vacuum vapor deposition method.

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