WO2021095294A1

WO2021095294A1 - Piezoelectric vibrator and method for manufacturing same

Info

Publication number: WO2021095294A1
Application number: PCT/JP2020/023572
Authority: WO
Inventors: 洋井原木
Original assignee: 株式会社村田製作所
Priority date: 2019-11-14
Filing date: 2020-06-16
Publication date: 2021-05-20
Also published as: JP7389410B2; JPWO2021095294A1

Abstract

A piezoelectric vibrator (1) is provided with a base member (30), a piezoelectric vibration element (10), a lid member (40) having a recess opening toward the piezoelectric vibration element (10), and a bonding member (50). The lid member (40) includes a top wall portion (41), a side wall portion (42), and a flange portion (43), and satisfies T3 ≧ H9, where T3 is the thickness of the flange portion (43) along a height direction, and H9 is the height of the recess of the lid member (40) along the height direction.

Description

Piezoelectric oscillator and its manufacturing method

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, small and thin piezoelectric vibrating elements are required.

Patent Document 1 includes an alumina substrate, a piezoelectric vibrating element bonded and fixed to the substrate, a metal lid member covering the piezoelectric vibrating element, and a joining member for bonding and fixing the substrate and the lid member. The lid member is obtained by drawing and molding a thin metal plate so that a flange portion is formed on the outer periphery of the opening, and then cutting the flange portion at a position near the outer surface of the lid member and parallel to the outer surface. Disclosed is a piezoelectric vibrator in which the opening is adhesively sealed with respect to the substrate in a substantially linear contact state.

Patent Document 2 includes a base member, a piezoelectric vibrating element mounted on the base member, and a lid member joined to the base member to form an internal space for accommodating the piezoelectric vibrating element together with the base member. The lid member has a top wall portion facing the base member 30 with the piezoelectric vibrating element interposed therebetween, and a side wall portion extending in a direction intersecting the main surface of the top wall portion, and the thickness of the top wall portion is increased. A piezoelectric vibrator that is larger than the thickness of the side wall portion is disclosed. The lid member is formed by deforming a flat metal member by a pressing method.

Japanese Unexamined Patent Publication No. 8-111627 JP-A-2018-98599

As described in Patent Document 1 and Patent Document 2, the thickness of the side wall portion of the lid member manufactured by the press method may be smaller than the thickness of the top wall portion. In a piezoelectric vibrator using such a lid member, the side wall portion of the lid member may be easily deformed. Deformation of the lid member may cause problems such as malfunction due to contact between the lid member and the piezoelectric vibrating element, and fluctuation of frequency characteristics due to airtight destruction due to damage to the base member.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a highly reliable piezoelectric vibrator and a method for manufacturing the same.

The piezoelectric vibrator according to one aspect of the present invention includes a base member, a piezoelectric vibrating element mounted on a mounting surface of the base member, a lid member having a recess opened on the side of the piezoelectric vibrating element, and a base member and a lid member. The lid member is provided with a joining member for joining the base member, and the lid member is connected to the top wall portion extending along the mounting surface of the base member and the outer edge of the top wall portion in the height direction intersecting the mounting surface of the base member. A side wall portion extending along the side wall portion and a flange portion extending outward from the side wall portion along the mounting surface of the base member are included, and the thickness of the flange portion along the height direction is T3, along the height direction. When the height of the recess of the lid member is H9, T3 ≧ H9 is satisfied.

The method for manufacturing a piezoelectric vibrator according to another aspect of the present invention includes a step of forming a lid member, a step of mounting a piezoelectric vibrating element on the base member, and a step of joining the lid member to the base member. The step of forming the lid member includes a step of preparing a plate-shaped member having a pair of main surfaces and a step of deforming the plate-shaped member along a direction intersecting the pair of main surfaces by a pressing method. When the thickness of the plate-shaped member is T3 and the depth of deformation by the pressing method is H9 in the direction intersecting the main surface of the above, T3 ≧ H9 is satisfied.

According to the present invention, a highly reliable piezoelectric vibrator and a method for manufacturing the same can be provided.

It is an exploded perspective 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 sectional drawing which shows schematic the structure of the end part of the lid member which concerns on 1st Embodiment. It is a flowchart which shows roughly the manufacturing method of the crystal oscillator which concerns on 1st Embodiment. It is sectional drawing which shows schematicly the process of holding an end portion of a metal plate. It is sectional drawing which shows typically the process of pressing the central part of a metal plate. It is a table which shows the free fall test condition. It is a table which shows the test result of the free fall test. It is sectional drawing which shows schematic the structure of the crystal oscillator which concerns on 2nd 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 3. FIG. 1 is an exploded perspective view schematically showing the configuration of the crystal oscillator according to the first embodiment. FIG. 2 is a cross-sectional 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 end portion of the lid member according to the first embodiment. Note that FIG. 2 is a cross-sectional view of the crystal oscillator 1 shown in FIG. 1 along the line II-II.

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 base member 30, a lid member 40, and a joining member 50. 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. In the examples shown in FIGS. 1 and 2, 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. The shape of the base member 30 is not limited to the above as long as at least the excited portion of the crystal vibrating element 10 is housed in the cage. 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 method of holding the crystal vibrating element 10 is not limited to the above. For example, the base member 30 and the lid member 40 may sandwich the peripheral portion of the excited portion of the crystal vibrating element 10. 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 artificial quartz (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 thickness 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 plan view, the plane shape of the crystal piece 11 is rectangular, and the crystal piece 11 is located in the center and is adjacent to the excitation unit 17 that contributes to excitation and the excitation unit 17. It has

peripheral portions

18 and 19. The excitation portion 17 and the

peripheral portions

18 and 19 are each formed in a band shape over the entire width along the Z'axis direction of the crystal piece 11. The peripheral portion 18 is located on the −X-axis direction side of the excitation portion 17, and the peripheral portion 19 is located on the + X-axis direction side of the excitation portion 17.

The planar shape of the crystal piece 11 when the upper surface 11A is viewed in a plane 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 shapes of the exciting portion 17 and the

peripheral portions

18 and 19 of the crystal piece 11 are not limited to the strip shape over the entire width. For example, the planar shape of the excitation portion may be an island shape adjacent to the peripheral portion in the Z'axis direction, and the planar shape of the peripheral portion may be formed in a frame shape surrounding the excitation portion.

The crystal piece 11 has a so-called mesa-shaped structure in which the thickness of the exciting portion 17 is larger than the thickness of the

peripheral portions

18 and 19. According to the crystal piece 11 having a mesa-shaped structure, vibration leakage from the exciting portion 17 can be suppressed. The crystal piece 11 has a double-sided mesa-shaped structure, and the excitation portions 17 project from the

peripheral portions

18 and 19 on both sides of the upper surface 11A and the lower surface 11B. The boundary between the exciting portion 17 and the peripheral portion 18 and the boundary between the exciting portion 17 and the peripheral portion 19 form a tapered shape in which the thickness changes continuously, but a staircase shape in which the change in thickness is discontinuous. May be good. The boundary may have a convex shape in which the amount of change in thickness changes continuously, or a bevel shape in which the amount of change in thickness changes discontinuously. The crystal piece 11 may have a single-sided mesa-shaped structure in which the exciting portion 17 projects from the

peripheral portions

18 and 19 on one side of the upper surface 11A or the lower surface 11B. Further, the crystal piece 11 may have a so-called inverted mesa type structure in which the thickness of the exciting portion 17 is smaller than the thickness of the

peripheral portions

18 and 19.

The first excitation electrode 14a and the second excitation electrode 14b are provided in the excitation unit 17. 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 first excitation electrode 14a and the second excitation electrode 14b are each formed in a band shape over the entire width along the Z'axis direction of the crystal piece 11. Each of the first excitation electrode 14a and the second excitation electrode 14b constituting the pair of electrodes corresponds to the electrodes facing each other with the crystal piece 11 interposed therebetween.

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 and the second extraction electrode 15b are provided on the peripheral portion 18. 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 example, as shown in FIG. 1, one end of the first extraction electrode 15a is connected to the first excitation electrode 14a in the excitation portion 17, and the other end of the first extraction electrode 15a is connected to the first connection electrode 16a in the peripheral portion 18. Has been done. Further, one end of the second extraction electrode 15b is connected to the second excitation electrode 14b at the excitation portion 17, and the other end of the second extraction electrode 15b is connected to the second connection electrode 16b at the peripheral portion 18. 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 the peripheral portion 18 of the crystal piece 11 It is provided on the lower surface 11B side. 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 electrode group 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 substrate 31 having 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 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.

The base member 30 includes a first electrode pad 33a and a second electrode pad 33b that form a pair of electrode pads. 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 base member 30 includes a first external electrode 35a, a second external electrode 35b, a third external electrode 35c, and a fourth external electrode 35d. 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 and the second external electrode 35b are terminals for electrically connecting an external circuit board (not shown) and the crystal oscillator 1. The third external electrode 35c and the fourth external electrode 35d are, for example, dummy electrodes to which an electric signal or the like is not input / output, but even if the lid member 40 is grounded to improve the electromagnetic shielding function of the lid member 20. Good. The third external electrode 35c and the fourth external electrode 35d may be omitted.

The first electrode pad 33a and the second electrode pad 33b are aligned along the Z'axis direction at the end of the base member 30 on the −X axis direction side. The first external electrode 35a and the second external electrode 35b are aligned along the Z'axis direction at the end of the base member 30 on the −X axis direction side. The third external electrode 35c and the fourth external electrode 35d are aligned along the Z'axis direction at the end of the base member 30 on the + X axis direction. The first electrode pad 33a is electrically connected to the first external electrode 35a via the first through electrode 34a that penetrates the substrate 31 along the Y'axis direction. The second electrode pad 33b is electrically connected to the second external electrode 35b via the second through electrode 34b that penetrates the substrate 31 along the Y'axis direction.

The first electrode pad 33a and the second electrode pad 33b are electrically connected to the first external electrode 35a and the second external electrode 35b via the side electrodes provided on the side surfaces connecting the upper surface 31A and the lower surface 31B of the substrate 31, respectively. May be connected. The first external electrode 35a to the fourth external electrode 35d may be a casting electrode provided in a concave shape on the side surface of the substrate 31.

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 so that the exciting portion 17 can be excited. The crystal vibrating element 10 is held so that the exciting portion 17 does not come into contact with 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 adheres the first electrode pad 33a and the first connecting electrode 16a, and the second conductive holding member 36b adheres 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 resin as long as they are curable resins, and may be, for example, epoxy resin or acrylic resin. 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 sealed in a vacuum state, for example, but may be sealed in a state filled with an inert gas such as nitrogen or a rare gas. 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 material of the lid member 40 may be the same as that of the substrate 31, and may include ceramic, crystal, resin, and the like. However, 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 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 further has a flange portion 43 that is connected to the tip end portion of the side wall portion 42 on the base member 30 side and extends outward along the upper surface 31A of the substrate 31. In other words, the top wall portion 41 connected to the upper end portion of the side wall portion 42 and the flange portion 43 connected to the lower end portion of the side wall portion 42 extend in opposite directions. When the upper surface 31A of the substrate 31 is viewed in a plan view, the flange portion 43 extends in a frame shape so as to surround the crystal vibrating element 10.

As shown in FIG. 3, the top wall portion 41 has a top wall lower surface 41B located on the side of the base member 30, and a top wall upper surface 41A located on the side opposite to the top wall lower surface 41B. The flange portion 43 has a flange lower surface 43B located on the side of the base member 30, and a flange upper surface 43A located on the side opposite to the flange lower surface 43B. The side wall portion 42 includes a side wall inner surface 42B that connects the top wall lower surface 41B and the flange lower surface 43B on the side of the recess 49, and a side wall outer surface 42A that connects the top wall upper surface 41A and the flange upper surface 43A on the side opposite to the side wall inner surface 42B. Have. The contact surface of the lid member 40 in contact with the joining member 50 is composed of a flange lower surface 43B of the flange portion 43 and a facing surface of the side wall portion 42 facing the base member 30. Therefore, the contact surface is enlarged as compared with the configuration without the flange portion 43, and the joint strength between the base member 30 and the lid member 40 is improved. The lower surface of the flange 43B of the flange portion 43 and the facing surface of the side wall portion 42 are continuous.

The corner portion connecting the lower surface 41B of the top wall and the inner surface 42B of the side wall has an R shape. Similarly, the corner portion connecting the inner surface surface 42B of the side wall and the lower surface 43B of the flange, the corner portion connecting the upper surface 41A of the top wall and the outer surface 42A of the side wall, and the corner portion connecting the outer surface 42A of the side wall and the upper surface 43A of the flange also have an R shape. ing. For example, the curvature of the corner portion connecting the top wall lower surface 41B and the side wall inner surface 42B is larger than the curvature of the corner portion connecting the top wall upper surface 41A and the side wall outer surface 42A. Further, the curvature of the corner portion connecting the inner surface surface 42B of the side wall and the lower surface 43B of the flange is larger than the curvature of the corner portion connecting the outer surface 42A of the side wall and the upper surface 43A of the flange.

The top wall portion 41 has a thickness T1 along the height direction (hereinafter, referred to as "top wall thickness T1"). The top wall thickness T1 corresponds to the shortest distance from the top wall lower surface 41B to the top wall top surface 41A. The side wall portion 42 has a thickness T2 (hereinafter, referred to as “side wall thickness T2”) along the upper surface 31A of the substrate 31. The side wall thickness T2 is a thickness along a direction orthogonal to the height direction, and corresponds to the shortest distance from the virtual inner surface extending from the side wall inner surface 42B to the side wall outer surface 42A. The flange portion 43 has a thickness T3 (hereinafter, referred to as “flange thickness T3”) along the height direction. The flange thickness T3 corresponds to the shortest distance from the flange lower surface 43B to the flange upper surface 43A. For example, the top wall thickness T1 and the flange thickness T3 are substantially the same size, and the side wall thickness T2 is smaller than the top wall thickness T1 or the flange thickness T3 (T2 <T1 = T3).

The magnitude relationship between the top wall thickness T1, the side wall thickness T2, and the flange thickness T3 is not limited to the above. The top wall thickness T1 may be larger than the flange thickness T3 (T3 <T1) and may be smaller than the flange thickness T3 (T1 <T3). The side wall thickness T2 may be substantially the same size as at least one of the top wall thickness T1 and the flange thickness T3 (T1 = T2 and / or T3 = T2), and is larger than at least one of the top wall thickness T1 or the flange thickness T3. May also be large (T1 ≦ T2 and / or T3 ≦ T2). Further, when the top wall portion 41 is not flat, that is, the top wall thickness T1 differs depending on the position and does not become a constant value, the minimum value of the top wall thickness T1 is smaller than at least one of the side wall thickness T2 and the flange thickness T3. It may be (T1min <T2 and / or T1min <T3), and the maximum value of the top wall thickness T1 may be larger than at least one of the side wall thickness T2 and the flange thickness T3 (T2 <T1max and / or T3 <T1max). Similarly, if the side wall thickness T2 differs depending on the position and does not become a constant value, the minimum value of the side wall thickness T2 may be smaller than at least one of the top wall thickness T1 and the flange thickness T3 (T2min <T1 and / or T2min). <T3), the maximum value of the side wall thickness T2 may be larger than at least one of the top wall thickness T1 and the flange thickness T3 (T1 <T2max and / or T3 <T2max). Similarly, if the flange thickness T3 differs depending on the position and does not become a constant value, the minimum value of the flange thickness T3 may be smaller than at least one of the top wall thickness T1 and the side wall thickness T2 (T3min <T1 and / or T3min). <T2), the maximum value of the flange thickness T3 may be larger than at least one of the top wall thickness T1 and the side wall thickness T2 (T1 <T3max and / or T2 <T3max).

The recess 49 has a height H9 along the height direction (hereinafter, referred to as "inner dimension height H9"). The inner dimension height H9 corresponds to the shortest distance from the virtual bottom surface extended from the flange lower surface 43B to the top wall lower surface 41B. The lid member 40 has a height H1 (hereinafter, referred to as “total height H1”) along the height direction. The total height H1 corresponds to the shortest distance from the virtual bottom surface extended from the flange lower surface 43B to the top wall upper surface 41A. The flange portion 43 has a width W3 (hereinafter, referred to as “flange width W3”) along the upper surface 31A of the substrate 31. The flange width W3 corresponds to the shortest distance from the virtual outer surface extended from the side wall outer surface 42A to the tip of the flange portion 43. Therefore, the width of the joint surface of the lid member 40 in contact with the joint member 50 is the sum of the side wall thickness T2 and the flange width W3.

The flange thickness T3 is smaller than the total height H1 (T3 <H1). Further, the flange thickness T3 is larger than the inner dimension height H9 (H9 ≦ T3), and is preferably larger than the inner dimension height H9 (H9 <T3). In other words, the flange upper surface 43A is located on the same plane as the top wall lower surface 41B, or the virtual extension surface extended from the flange upper surface 43A is located between the top wall upper surface 41A and the top wall lower surface 41B. According to this, since the flange portion 43 guarantees the mechanical strength of the lid member 40 against an impact from the outside, the deformation of the lid member 40 can be suppressed. The total height H1 is the sum of the inner dimension height H9 and the top wall thickness T1 (H1 = H9 + T1). From the viewpoint of improving the mechanical strength of the lid member 40, the total height H1 is equal to or less than the sum of the top wall thickness T1 and the flange thickness T3 (H1 ≦ T1 + T3), and preferably the top wall thickness T1 and the flange. It is smaller than the sum with the thickness T3 (H1 <T1 + T3).

When the top wall portion 41 and the flange portion 43 are not flat, in other words, when the top wall thickness T1, the flange thickness T3, the inner dimension height H9 and the total height H1 are different depending on the position and do not become constant values, the top wall thickness T1 The magnitude relation of the flange thickness T3, the inner dimension height H9, and the total height H1 is not limited to the above. When the maximum value of the flange thickness T3 is T3max, the minimum value is T3min, the maximum value of the inner dimension height H9 is H9max, and the minimum value is H9min, it can be said that H9≤T3 is satisfied if H9min≤T3max. Therefore, when H9 ≦ T3 is satisfied, T3min <H9min may be satisfied, but preferably H9min ≦ T3min, and more preferably H9min <T3min. Further, when H9 ≦ T3 is satisfied, it is desirable that H9max ≦ T3max, and more preferably H9max <T3max. Similarly, when H9 ≦ T3 is satisfied, it is desirable that H9max ≦ T3min, and more preferably H9max <T3min.

In order for the flange portion 43 to sufficiently secure the mechanical strength against impact from the lateral direction, the sum of the flange width W3 and the side wall thickness T2 is as large as, for example, the inner dimension height H9 (H9 ≦ W3 + T2). ), Desirably, the sum of the flange width W3 and the side wall thickness T2 is larger than the inner dimension height H9 (H9 <W3 + T2). Further, more preferably, the sum of the flange width W3 and the side wall thickness T2 is equal to or larger than the flange thickness T3 (T3 ≦ W3 + T2), and more preferably, the sum of the flange width W3 and the side wall thickness T2 is the flange thickness T3. Greater than (T3 <W3 + T2). Further, more preferably, the sum of the flange width W3 and the side wall thickness T2 is equal to or larger than the total height H1 (H1 ≦ W3 + T2), and more preferably, the sum of the flange width W3 and the side wall thickness T2 is larger than the total height H1. Large (H1 <W3 + T2). Similarly, in order to sufficiently secure the mechanical strength, it is desirable that the flange width W3 is equal to or larger than the side wall thickness T2 (T2 ≦ W3), and more preferably the flange width W3 is equivalent to the inner dimension height H9. It has the above size (H9 ≦ W3), and more preferably, the flange width W3 is equal to or larger than the flange thickness T3 (T3 ≦ W3).

When each of the side wall thickness T2, the flange width W3, the inner dimension height H9 and the total height H1 differs depending on the position and does not become a constant value, the magnitude relationship of the side wall thickness T2, the flange width W3, the inner dimension height H9 and the total height H1 is described above. It is not limited. When the maximum value of the inner dimension height H9 is H9max, the maximum value of the sum of the side wall thickness T2 and the flange width W3 is (W3 + T2) max, and the minimum value is (W3 + T2) min, then H9max≤ (W3 + T2) max is H9. It can be said that ≦ W3 + T2 is satisfied. Therefore, when H9 ≦ W3 + T2, (W3 + T2) min <H9max may be satisfied, but H9max ≦ (W3 + T2) min is desirable. Similarly, when H9 <(W3 + T2) is satisfied, H9max <(W3 + T2) max may be satisfied, and H9max <(W3 + T2) min is desirable. Further, when the maximum value of the flange thickness T3 is T3max and the minimum value is T3min, if T3max ≦ (W3 + T2) max, it can be said that T3 ≦ W3 + T2 is satisfied. Therefore, when T3 ≦ W3 + T2, (W3 + T2) min <T3max may be set, but preferably T3max ≦ (W3 + T2) min. Similarly, when T3 <W3 + T2 is satisfied, T3max <(W3 + T2) max may be satisfied, and T3max <(W3 + T2) min is desirable. Further, when the maximum value of the total height H1 is H1max and the minimum value is H1min, if H1max ≦ (W3 + T2) max, it can be said that H1 ≦ W3 + T2 is satisfied. Therefore, when H1 ≦ W3 + T2, (W3 + T2) min <H1max may be satisfied, but H1max ≦ (W3 + T2) min is desirable.

Similarly, the magnitude relationship between the flange width W3 and the side wall thickness T2 is not limited to the above. When the maximum value of the flange width W3 is W3max, the minimum value is W3min, the maximum value of the side wall thickness T2 is T2max, and the minimum value is T2min, it can be said that T2≤W3 is satisfied if T2min≤W3max. Therefore, when T2 ≦ W3, W3min <T2min may be satisfied, but T2min ≦ W3min is desirable. When T2 ≦ W3, it is desirable that T2max ≦ W3max, and W3min <T2max may be satisfied, but more preferably T2max ≦ W3min.

Similarly, the magnitude relationship between the flange width W3 and the inner dimension height H9 is not limited to the above. When the maximum value of the flange width W3 is W3max, the minimum value is W3min, the maximum value of the inner dimension height H9 is H9max, and the minimum value is H9min, it can be said that H9≤W3 is satisfied if H9min≤W3max. Therefore, when H9 ≦ W3, W3min <H9min may be satisfied, but H9min <W3min is desirable. When H9 ≦ W3, it is desirable that H9max ≦ W3max, and W3min <H9max may be satisfied, but more preferably H9max ≦ W3min.

Similarly, the magnitude relationship between the flange width W3 and the flange thickness T3 is not limited to the above. When the maximum value of the flange width W3 is W3max, the minimum value is W3min, the maximum value of the flange thickness T3 is T3max, and the minimum value is T3min, it can be said that T3≤W3 is satisfied if T3min≤W3max. Therefore, when T3 ≦ W3, W3min <T3min may be satisfied, but T3min <W3min is desirable. When T3 ≦ W3, it is desirable that T3max ≦ W3max, and W3min <T3max may be satisfied, but more preferably T3max ≦ W3min.

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 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 joining member 50 will be described.
The joining member 50 is provided over the entire circumference of each 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 vibrating 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 base 31 and the flange portion 43. 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. Further, in order to electrically connect the lid member 40 to the ground potential via the joining member 50, it is desirable that the joining member 50 has conductivity. From these viewpoints, the material of the joining member 50 is preferably metal. As an example, the joining member 50 is a combination of a metallized layer made of molybdenum (Mo) provided on the upper surface 31A of the substrate 31 and a gold tin (Au—Sn) system provided between the metallized layer and the flange portion 43. It is provided by a metal solder layer made of a crystal alloy.

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 epoxy-based, vinyl-based, acrylic-based, urethane-based, or silicone-based organic adhesive. When the joining member 50 is provided with an inorganic or organic adhesive, a coating having a lower gas permeability than the adhesive may be provided on the outside of the joining member 50 in order to reduce the gas permeability. The base member 30 and the lid member 40 may be joined by seam welding.

Next, a method for manufacturing the crystal oscillator 1 will be described with reference to FIGS. 4 to 6. FIG. 4 is a flowchart schematically showing a method for manufacturing a crystal oscillator according to the first embodiment. FIG. 5 is a cross-sectional view schematically showing a step of holding an end portion of a metal plate. FIG. 6 is a cross-sectional view schematically showing a process of pressing the central portion of the metal plate.

First, a metal plate is prepared (S10).
The metal plate 140 to be prepared is made of an Fe—Ni—Co alloy. The metal plate 140 is a plate-like member having a pair of main surfaces composed of a first main surface 140A and a second main surface 140B facing each other. The metal plate 140 is a flat plate having a uniform thickness (the shortest distance between the first main surface 140A and the second main surface 140B), and the thickness of the metal plate 140 is T3.

Next, the metal plate is drawn (S20).
The metal plate 140 is deformed by a pressing method to form a top wall portion 41, a side wall portion 42, and a flange portion 43.

First, as shown in FIG. 5, the metal plate 140 is sandwiched between the die AP1 and the holder AP2. The die AP1 supports the metal plate 140 from the first main surface 140A side. The holder AP2 presses the metal plate 140 against the die AP1 from the first main surface 140A side. The holder AP2 suppresses fluctuations in the processing position of the metal plate 140, and also suppresses the occurrence of wrinkles in the metal plate 140 during deformation due to press processing. The punch AP3 is set on the second main surface 140B side of the metal plate 140. The clearance between the die AP1 and the punch AP3 when the second main surface 140B of the metal plate 140 is viewed in a plan view is set to T2.

Next, as shown in FIG. 6, the punch AP3 is pushed into the metal plate 140 to deform the metal plate 140. The second main surface 140B side of the metal plate 140 is deformed in a concave shape, and the first main surface 140A side is deformed in a convex shape. The space surrounded by the metal plate 140 formed by pushing the punch AP3 becomes the recess 49. At this time, the depth at which the metal plate 140 is pushed in the direction in which the punch AP3 intersects the pair of main surfaces (first main surface 140A and second main surface 140B) of the metal plate 140 is defined as H9. The depth H9 is formed on the first main surface 140A side of the metal plate 140 and the depth based on the second main surface 140B of the recess formed on the second main surface 140B side of the metal plate 140. It corresponds to the height when the first main surface 140A of the convex portion is used as a reference. The depth H9 is set to a size equal to or less than the thickness T3 (T3 ≧ H9). That is, the metal plate 140 is drawn by a pressing method to a depth equal to or less than its thickness. As a result, in the metal plate 140, the portion where the tip of the punch AP3 faces is the top wall portion 41, and the portion located at the clearance between the die AP1 and the punch AP3 becomes the side wall portion 42, and the die AP1 and the holder AP2 The portion sandwiched between the two becomes the flange portion 43.

Next, the base member is prepared (S30).
The substrate 31 is formed by sintering a green sheet of alumina. A metal film is provided on the green sheet before sintering, and the metal film sintered together with the green sheet forms a metallized layer of the joining member 50,

electrode pads

33a and 33b, and external electrodes 35a to 35d. 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 31 may be formed of a wafer cut out from an ingot. The metal film may be formed by a dry process using various vapor deposition methods such as PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition) as an example. At least a part of each of the metallized layer of the joining member 50, the

electrode pads

33a and 33b, and the external electrodes 35a to 35d may be formed after sintering the green sheet.

Next, a crystal vibrating element is prepared (S40).
First, a crystal of crystal is sliced to form a crystal wafer. The crystal wafer may be subjected to appropriate necessary treatments such as flattening treatment such as chemical mechanical polishing and cleaning treatment with a rinsing liquid.
Next, a part of the crystal wafer is removed and processed to form contours of a plurality of crystal pieces connected to each other. Next, a part of each of the plurality of crystal pieces is removed, and each of the plurality of crystal pieces is processed into a mesa-shaped structure. The removal process is performed by, for example, etching using photolithography, but may be performed by another processing method such as plasma CVM (Chemical Vaporization Machining).
Next, a metal film is provided on the surface of each of the plurality of crystal pieces, and a part of the metal film is removed by etching using photolithography to form an electrode from the metal film. The method of forming the electrode is not limited to etching, and the electrode may be formed by lift-off.
Finally, the crystal vibrating element is individualized. A thin-walled portion thinner than the surroundings is formed in the portion connecting the plurality of crystal pieces, and the thin-walled portion becomes the starting point of cracks by applying bending stress, and the portion connecting the plurality of crystal pieces is cut. To. The thin-walled portion is formed by utilizing, for example, etching in a step of forming contours of a plurality of quartz pieces or a step of processing each of the plurality of quartz pieces into a mesa-shaped structure. The thin portion may be formed by a scribe tool. The crystal vibrating element may be individualized by cutting with a laser cutter, a dicing saw, or the like.

Next, a crystal vibrating element is mounted (S50).
Increasingly, a conductive adhesive paste containing a composition of thermosetting resin is prepared. Next, the base member 30 is placed on a hot plate that has not been heated. Next, the conductive adhesive paste is applied onto each of the first electrode pad 33a and the second electrode pad 33b of the base member 30. Next, the crystal vibrating element 10 is placed on the conductive adhesive paste so that the tip of the crystal vibrating element 10 does not come into contact with the base member 30. Next, the conductive adhesive paste is heated and cured on a hot plate to cure the first electrode pad 33a and the second electrode pad 33b of the base member 30, respectively, and the first connection electrodes 16a and the second of the crystal vibration element 10. Each of the connection electrodes 16b is joined.

Before placing the crystal vibration element 10 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 light (UV) curable resin. In this case, the step S40 may include a step of irradiating the conductive adhesive paste with light (UV).

Next, the base member and the lid member are joined (S60).
First, the lid member 40 is put into the storage tray. The storage tray is provided with a bottomed opening in which the lid member 40 can be stored with almost no gap. The lid member is housed in the opening with the top surface 41A of the top wall 41 facing the bottom of the opening.
Next, metal solder is provided on the lower surface 43B of the flange of the flange portion 43. The metal solder is a gold-tin (Au—Sn) -based eutectic alloy. The metal solder may be provided on the metallized layer provided on the base member 30.
Next, the base member is placed in the storage tray. The base member 30 on which the crystal vibrating element 10 is mounted is housed in the opening with the crystal vibrating element 10 facing the lid member 40 side. At this time, the metallized layer of the base member 30 overlaps the metal solder of the lid member 40.
Next, the metal solder is heated to soften it, and the softened metal solder is cooled to solidify. The solidified metal solder forms a joining member 50 together with the metallized layer of the base member 30, and joins the base member 30 and the lid member 40 to seal the recess 49 corresponding to the internal space.
Finally, the crystal oscillator 1 is taken out from the storage tray.

The order of the steps S10 and S20 for forming the lid member 40 from the metal plate 140, the step S30 for preparing the base member 30, and the step S40 for preparing the crystal oscillator 10 is not limited to the above. .. The steps S10 and S20 for forming the lid member 40 from the metal plate 140 may be carried out after the step S30 for preparing the base member 30, or may be carried out after the step S40 for preparing the crystal vibration element 10. The step S30 for preparing the base member 30 may be performed after the step S40 for preparing the crystal vibration element 10.

(Durability evaluation)
Next, the results of the evaluation test regarding durability will be described with reference to FIGS. 7 and 8. FIG. 7 is a table showing the free fall test conditions. FIG. 8 is a table showing the test results of the free fall test.

The configuration of the first embodiment shall conform to the crystal oscillator 1 shown in FIGS. 1 to 3, and configurations other than those already described will be described below. The external dimensions are expressed as "length along the X axis x length along the Z'axis x length along the Y'axis".
The frequency of the crystal vibrating element is 37.4 Hz, and the ESR is 30 Ω.
The base of the base member is made of alumina and has external dimensions of 1.0 mm × 0.8 mm × 0.12 mm.
The joining member includes a gold-tin alloy having a thickness of 15 μm and a width of 60 μm.
The lid member is made of a Fe—Ni—Co alloy and has external dimensions of 1.0 mm × 0.8 mm × 0.16 mm. Top wall thickness T1 is 0.06 mm, side wall thickness T2 is 55 μm, flange thickness T3 is 0.1 mm, flange width W3 is 85 μm, internal height H9 is 0.1 mm, and total height H1 is along the Y'axis direction of external dimensions. It is 0.16 mm, which corresponds to the length of the flange. That is, in the first embodiment, the flange thickness T3 is the same size as the internal dimension height H9 (T3 = H9).

The configuration of the second embodiment is the same as that of the first embodiment except that the flange thickness T3 is 0.16 mm. That is, in the second embodiment, the flange thickness T3 is larger than the inner dimension height H9 (T3> H9).

The configuration of the comparative example is the same as that of the first embodiment except that the flange thickness T3 is 0.06 mm. That is, in the comparative example, the flange thickness T3 is smaller than the inner dimension height H9 (T3 <H9).

In order to evaluate the occurrence of defects due to the deformation of the lid member, a free fall test in accordance with JIS C 60068-2-31 (2013) was performed as shown in FIG. 7, and fluctuations in frequency or ESR were measured. Specifically, the crystal oscillators according to the comparative examples, the first embodiment and the second embodiment are naturally dropped toward a flat floor surface in a normal posture during transportation. The floor material is concrete, and in test 1, it is naturally dropped twice from a height of 750 mm from the floor surface, and the frequency fluctuation before and after the test is ± 10 ppm or more with respect to the frequency before the test, or the ESR fluctuation before and after the test. Was ± 10 ohms or more with respect to the ESR before the test, and was judged to be defective. Similarly, in Test 2, defects were determined by spontaneously dropping from a height of 1000 mm from the floor surface twice, and in Test 3, defects were determined by spontaneously dropping twice from a height of 1500 mm from the floor surface. Evaluation was performed on 22 samples in each of Tests 1 to 3.

As shown in FIG. 8, in the comparative example, the number of defects in Test 1 was 0, but in

Test

2, 2 defects occurred, and in Test 3, 7 defects occurred. On the other hand, in the first example and the second example, the number of defects occurred was 0 in any of the tests 1 to 3. Although the difference between the example and the comparative example was only the size of the flange thickness T3, the defect that occurred in the comparative example did not occur in the example. The difference between the comparative example and the embodiment is, more specifically, the mechanical strength of the lid member, which is determined by the configuration of the flange portion. Therefore, it is considered that the occurrence of defects in this evaluation test was caused by the deformation of the lid member. For example, when the lid member is plastically deformed, the vibration may be hindered by the contact between the lid member and the crystal vibration element. In addition, regardless of whether the lid member is deformed plastically or elastically, the deformation of the lid member causes distortion in the joint member and the base member, so that the internal space becomes airtight due to damage to the substrate and interfacial peeling of the joint member. It may be destroyed. In the comparative example in which the flange thickness T3 was smaller than the inner dimension height H9, the drop caused inhibition of vibration and destruction of airtightness. However, in the first embodiment in which the flange thickness T3 is the same size as the inner dimension height H9 and the second embodiment in which the flange thickness T3 is larger than the inner dimension height H9, vibration is hindered and airtightness is destroyed by dropping. Did not occur. From this, it can be seen that if the flange thickness T3 has a size equal to or higher than the inner dimension height H9, the defect of the crystal oscillator due to the mechanical strength of the lid member does not occur.

As described above, in the first embodiment, the total height H1 of the lid member 40, the internal dimension height H9, and the flange thickness T3 satisfy H1> T3 ≧ H9. Further, the total height H1 of the lid member 40, the top wall thickness T1 and the flange thickness T3 satisfy H1 ≦ T1 + T3.
According to this, the mechanical strength of the lid member 40 is improved, and the physical durability of the crystal oscillator 1 is improved. Specifically, deformation of the lid member 40 due to an impact such as dropping can be suppressed. Therefore, it is possible to suppress fluctuations in vibration characteristics due to contact between the crystal vibration element 10 and the lid member 40 due to deformation of the lid member 40. Further, it is possible to suppress the destruction of airtightness due to damage to the base 31 and the joining member 50 due to the deformation of the lid member 40, and to suppress the fluctuation of the vibration characteristics due to the oxidation of the electrode of the crystal vibration element 10. From the above, a highly reliable crystal oscillator 1 can be provided.

The side wall thickness T2, the flange thickness T3, and the flange width W3 of the lid member 40 satisfy T3 <W3 + T2.
According to this, the flange portion 43 can sufficiently improve the mechanical strength of the lid member 40.

The base member 30 has a base 31 to which the lid member 40 and the crystal vibrating element 10 are joined. Further, the elastic modulus of the lid member 40 is smaller than the elastic modulus of the substrate 31.
Even if the lid member 40 is easily deformed and stress is easily concentrated on the substrate 31, the reliability of the crystal oscillator 1 is improved according to the present embodiment.

The material of the lid member 40 is 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 pressing method or the like.

The material of the substrate 31 is ceramic.
According to this, even if the substrate 31 is provided with the ceramic which is a brittle material which is easily damaged such as cracks, the reliability of the crystal oscillator 1 can be improved according to the present embodiment.

The substrate 31 has a flat plate shape.
According to this, the manufacturing process can be simplified and the manufacturing cost can be reduced as compared with, for example, a crystal unit having a substrate having a concave portion formed therein.

In the first embodiment, the step of forming the lid member 40 includes a step of deforming the metal plate 140 by the press method, and when the thickness of the metal plate 140 is T3 and the depth of deformation by the press method is H9. Satisfy T3 ≧ H9.
According to this, the highly reliable crystal oscillator 1 can be manufactured at low cost.

The configuration of the crystal oscillator 1 according to another embodiment of the present invention will be described below. In the following embodiment, the matters common to the above-mentioned first embodiment will be omitted, and only the differences will be described. In particular, the same effects of the same configuration will not be mentioned sequentially.

<Second Embodiment>
Next, with reference to FIG. 9, the configuration of the outer edge portion of the crystal oscillator 2 and its vicinity according to the second embodiment will be described. FIG. 9 is a cross-sectional view schematically showing the configuration of the crystal oscillator according to the second embodiment.

The base 31 is formed with a bottomed recess 39 that opens on the upper surface 31A side. When the substrate 31 is viewed in a plan view from the side of the crystal vibrating element 10, the recess 39 overlaps at least the exciting portion 17. In other words, the recess 39 overlaps at least the first excitation electrode 14a and the second excitation electrode 14b. Further, the recess 39 preferably overlaps at least a part of each of the peripheral portion 18 and the peripheral portion 19, and more preferably overlaps with the entire peripheral portion 19. The crystal vibrating element 10 may be tilted so that its tip (peripheral portion 19) is closer to the base member 30 than its root (peripheral portion 18).

According to this, the internal space in which the crystal vibrating element 10 is housed is formed by the recess 49 and the recess 39. Therefore, even if the crystal oscillator 1 is miniaturized, a sufficient space for the crystal vibrating element 10 to vibrate can be secured, and the amplitude of the crystal vibrating element 10 is not limited. In other words, the crystal unit 1 can be miniaturized. Further, when the crystal vibrating element 10 is mounted on the base member 30, contact between the tip of the crystal vibrating element 10 and the base member 30 can be suppressed even when the crystal vibrating element 10 is tilted by its own weight.

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 base member, the crystal vibrating element mounted on the mounting surface of the base member, the lid member having a recess opened on the side of the crystal vibrating element, and the base member and the lid member are joined. The lid member extends along the height direction of the top wall portion extending along the mounting surface of the base member and the lid member connected to the outer edge of the top wall portion and intersecting the mounting surface of the base member. The thickness of the flange portion along the height direction is T3, and the thickness of the lid member along the height direction is T3, including the existing side wall portion and the flange portion extending outward from the side wall portion along the mounting surface of the base member. When the height of the recess is H9, a crystal oscillator satisfying T3 ≧ H9 is provided.
According to this, the mechanical strength of the lid member is improved, and the physical durability of the crystal unit is improved. Specifically, deformation of the lid member due to an impact such as dropping can be suppressed. Therefore, it is possible to suppress fluctuations in vibration characteristics due to contact between the crystal vibration element and the lid member due to deformation of the lid member. Further, it is possible to suppress the destruction of airtightness due to damage to the substrate and the joining member due to the deformation of the lid member, and to suppress the fluctuation of the vibration characteristics due to the oxidation of the electrode of the crystal vibration element. From the above, a highly reliable crystal unit can be provided.

As one aspect, when the thickness of the side wall portion along the mounting surface of the base member is T2 and the width of the flange portion along the mounting surface of the base member is W3, T3 <W3 + T2 is satisfied.
According to this, the flange portion can sufficiently improve the mechanical strength of the lid member.

As one aspect, the base member has a substrate to which the lid member is joined and an electrode pad provided on the side of the substrate facing the lid member and to which the crystal vibration element is electrically connected.

In one aspect, the elastic modulus of the lid member is smaller than the elastic modulus of the substrate.
According to this embodiment, the reliability of the crystal unit is improved even if the lid member is easily deformed and stress is easily concentrated on the substrate.

In one aspect, the material of the lid member is metal.
According to this, even if the lid member is made of a ductile material, the lid member having the shape according to the present embodiment can be easily formed by drawing processing by a pressing method or the like.

In one aspect, the material of the substrate is ceramic.
According to this, even if the substrate is provided with ceramic, which is a brittle material that is easily damaged such as cracks, the reliability of the crystal unit can be improved according to the present embodiment.

In one aspect, the substrate is flat.
According to this, the manufacturing process can be simplified and the manufacturing cost can be reduced as compared with, for example, a crystal unit having a substrate having a concave portion formed therein.

As one aspect, a recess is formed on the side of the substrate facing the crystal vibrating element, and when the substrate is viewed in a plan view from the side of the crystal vibrating element, the recess overlaps at least the excitation electrode of the crystal vibrating element.
According to this, the internal space for accommodating the crystal vibrating element is formed by the recess on the base member side and the recess on the lid member side. Therefore, even if the crystal oscillator is miniaturized, the vibration space of the crystal vibrating element can be sufficiently secured, and the amplitude of the crystal vibrating element is not limited. In other words, the crystal unit can be miniaturized. Further, when the crystal vibrating element is mounted on the base member, contact between the tip of the crystal vibrating element and the base member can be suppressed even when the crystal vibrating element is tilted due to its own weight.

According to another aspect of the present invention, there is a step of forming the lid member, a step of mounting the crystal vibrating element on the base member, and a step of joining the lid member to the base member, and forming the lid member. Has a step of preparing a plate-shaped member having a pair of main surfaces and a step of deforming the plate-shaped member along a direction intersecting the pair of main surfaces by a pressing method, and intersects the pair of main surfaces. In the direction, when the thickness of the plate-shaped member is T3 and the depth of deformation by the pressing method is H9, T3 ≧ H9 is satisfied.
According to this, a highly reliable crystal unit can be manufactured at low cost.

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 the 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, a highly reliable piezoelectric vibrator and a method for manufacturing the same can be provided.

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. For example, the vibrating element and oscillator of the present invention can be used in a timing device or a load sensor. 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,
11 ... Crystal piece,
30 ... Base member,
31 ... Hypokeimenon,
40 ... Lid member,
41 ... Top wall,
42 ... Side wall,
43 ... Flange part,
50 ... Joining member,
T1 ... Top wall thickness,
T2 ... Side wall thickness,
T3 ... Flange thickness,
W3 ... Flange width,
H1 ... Overall height,
H9 ... Inner dimension height

Claims

With the base member
Piezoelectric vibrating elements mounted on the mounting surface of the base member,
A lid member having a recess that opens on the side of the piezoelectric vibrating element,
A joining member for joining the base member and the lid member is provided.
The lid member is
A top wall portion extending along the mounting surface of the base member,
A side wall portion connected to the outer edge of the top wall portion and extending along the height direction intersecting the mounting surface of the base member, and a side wall portion.
Including a flange portion extending outward from the side wall portion along the mounting surface of the base member.
When the thickness of the flange portion along the height direction is T3 and the height of the recess of the lid member along the height direction is H9.
T3 ≧ H9
Piezoelectric oscillator that meets the requirements.
When the thickness of the side wall portion along the mounting surface of the base member is T2 and the width of the flange portion along the mounting surface of the base member is W3.
T3 <W3 + T2
Meet,
The piezoelectric vibrator according to claim 1.
The base member is
The substrate to which the lid member is bonded and
It has an electrode pad provided on the side of the substrate facing the lid member and to which the piezoelectric vibrating element is electrically connected.
The piezoelectric vibrator according to claim 1 or 2.
The elastic modulus of the lid member is smaller than the elastic modulus of the substrate.
The piezoelectric vibrator according to claim 3.
The material of the lid member is metal.
The piezoelectric vibrator according to claim 3 or 4.
The material of the substrate is ceramic.
The piezoelectric vibrator according to any one of claims 3 to 5.
The substrate is flat,
The piezoelectric vibrator according to any one of claims 3 to 6.
A recess is formed on the side of the substrate facing the piezoelectric vibrating element.
When the substrate is viewed in a plan view from the side of the piezoelectric vibrating element, the recess overlaps with at least the excitation electrode of the piezoelectric vibrating element.
The piezoelectric vibrator according to any one of claims 3 to 6.
The process of forming the lid member and
The process of mounting the piezoelectric vibration element on the base member and
A step of joining the lid member to the base member is provided.
The step of forming the lid member is
The process of preparing a plate-shaped member having a pair of main surfaces, and
It has a step of deforming the plate-shaped member along a direction intersecting with the pair of main surfaces by a pressing method.
When the thickness of the plate-shaped member is T3 and the depth of deformation by the press method is H9 in the direction intersecting the pair of main surfaces.
T3 ≧ H9
A method for manufacturing a piezoelectric vibrator that satisfies the above conditions.