JP2023013314A - Piezoelectric vibrator and method for manufacturing the same - Google Patents

Abstract

To provide a crystal vibrator in which frequency fluctuation can be suppressed, and a method for manufacturing the same.SOLUTION: A piezoelectric vibrator (1) includes a piezoelectric vibration element (10) having a piezoelectric piece (11) and excitation electrodes (14a and 14b) configured so as to apply a voltage to the piezoelectric piece (11), a base member (30) mounted with the piezoelectric vibration element (10), conductive holding members (36a and 36b) for electrically connecting the piezoelectric vibration element (10) and the base member (30), a lid member (40) for storing the piezoelectric vibration element (10) in an internal space provided between the base member (30) and the lid member (40), and a joint member (50) for joining the base member (30) and the lid member (40), wherein in the internal space, a resin member (70) as a supply source of a resin film (CT) for coating a foreign matter existing in the internal space is provided in at least one of the base member (30) and the lid member (40).SELECTED DRAWING: Figure 2

Description

The present invention relates to a piezoelectric vibrator and its manufacturing method.

Piezoelectric vibrators are used for various purposes such as timing devices, sensors, and oscillators in various electronic devices such as mobile communication terminals, communication base stations, and home appliances.

As an example of a piezoelectric vibrator, Patent Document 1 discloses a rectangular substrate, a frame body provided along the outer peripheral edge of the upper surface of the substrate, electrode pads provided on the upper surface of the substrate, and mounting on the electrode pads. A crystal device is disclosed that includes a crystal element mounted on a substrate, a lid for hermetically sealing the crystal element, and an adhesive layer provided on the upper surface of a substrate.

JP 2018-74227 A

According to the crystal device described in Patent Document 1, foreign matter can be attached to the adhesive layer provided on the upper surface of the substrate, so that frequency fluctuation that can occur due to adhesion of foreign matter directly below the crystal element to the crystal element is suppressed. be done. However, for example, when foreign matter adhering to the crystal element scatters to a region other than the adhesive layer of the substrate or the lid, or when foreign matter adheres to the lid, it is difficult to capture the foreign matter. Also, there are cases where frequency fluctuation occurs due to attachment and detachment of foreign matter to and from the crystal element.

SUMMARY OF THE INVENTION An object of the present invention is to provide a piezoelectric vibrator capable of suppressing frequency fluctuations and a method of manufacturing the same.

A piezoelectric vibrator according to an aspect of the present invention includes a piezoelectric vibrating element having a piezoelectric piece and an excitation electrode configured to apply a voltage to the piezoelectric piece, a base member on which the piezoelectric vibrating element is mounted, and a piezoelectric vibrating element. a conductive holding member that electrically connects with the base member; a lid member that accommodates the piezoelectric vibrating element in an internal space provided between the base member and the base member; a bonding member that bonds the base member and the lid member; In the internal space, at least one of the base member and the lid member is provided with a resin member serving as a supply source of a resin film for covering foreign matter present in the internal space.

A method of manufacturing a piezoelectric vibrator according to another aspect of the present invention includes preparing a base member; preparing a lid member; providing a resin member on at least one of the base member and the lid member; By mounting the piezoelectric vibrating element on the member, by mounting one of the base member and the lid member on the other, and by using the resin member accommodated in the internal space between the base member and the lid member as a supply source, the inner space and forming a resin film to cover foreign matter present in the.

According to the present invention, it is possible to provide a piezoelectric vibrator capable of suppressing frequency fluctuations and a method of manufacturing the same.

1 is an exploded perspective view schematically showing the configuration of a crystal resonator according to a first embodiment; FIG. 1 is a cross-sectional view schematically showing the configuration of a crystal resonator according to a first embodiment; FIG. FIG. 2 is a plan view schematically showing configurations of a base member and a crystal vibrating element according to the first embodiment; 4 is a flow chart schematically showing a method for manufacturing a crystal resonator according to the first embodiment; FIG. 5 is a cross-sectional view schematically showing the configuration of a crystal oscillator according to a second embodiment; It is a top view showing roughly composition of a base member concerning a 3rd embodiment, and a crystal oscillating element.

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 construed as being limited to the embodiments.

An orthogonal coordinate system consisting of the X-axis, Y'-axis and Z'-axis is attached to each drawing for convenience in order to clarify the relationship between each drawing and to help understand the positional relationship of each member. Sometimes. The X-axis, Y'-axis, and Z'-axis indicate an orthogonal coordinate system used to specify the structure of an AT-cut crystal, which is an example of a crystal piece. The X-axis, Y'-axis and Z'-axis correspond to each other in each drawing. The X-axis, Y'-axis, and Z'-axis are related to crystallographic axes of the crystal piece 11, which will be described later. Specifically, in an orthogonal coordinate system in which the electric axis (polar axis) of the quartz crystal is the X-axis, the mechanical axis of the quartz crystal is the Y-axis, and the optical axis of the quartz crystal is the Z-axis, the Y′-axis and Z′-axis The axes correspond to the Y-axis and Z-axis, respectively, rotated about the X-axis from the Y-axis in the direction of the Z-axis by 35 degrees 15 minutes±1 minute 30 seconds.

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

A quartz crystal resonator unit 1 includes a quartz crystal resonator 10, a base member 30, a first conductive holding member 36a and a second conductive holding member which constitute a pair of conductive holding members. A member 36b, a lid member 40, a joint member 50, and a resin member 70 are provided. The crystal oscillator 10 is housed in an internal space provided between the base member 30 and the lid member 40 . That is, the base member 30 and the lid member 40 constitute a retainer for housing the crystal vibrating element 10 . In the inner space of the holder, the crystal resonator element 10 is sealed, for example, in a vacuum state, but may be sealed in a state filled with an inert gas such as nitrogen or rare gas. In the example shown in FIGS. 1 and 2 , the base member 30 has a flat plate shape, and the crystal vibrating element 10 is housed in the concave portion 49 of the lid member 40 . However, the shapes of the base member 30 and the lid member 40 are not limited to the above, as long as at least the portion of the crystal vibrating element 10 to be excited is accommodated in the retainer. For example, the base member 30 may have a recess that accommodates at least part of the crystal vibrating element 10 on the lid member 40 side.

The crystal vibrating element 10 is an electromechanical energy conversion element capable of converting electrical energy and mechanical energy by a piezoelectric effect. The crystal vibrating element 10 includes a flaky crystal element 11, a first excitation electrode 14a and a second excitation electrode 14b forming a pair of excitation electrodes, and a first extraction electrode forming a pair of extraction electrodes. 15a and a second extraction 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 ceiling wall portion 41 of the lid member 40, which will be described later. The lower surface 11B is located on the side facing the base member 30 . The upper surface 11A and the lower surface 11B correspond to a pair of principal surfaces of the crystal piece 11. As shown in FIG.

The crystal piece 11 is, for example, an AT-cut crystal. An AT-cut quartz crystal has a plane parallel to the plane specified by the X-axis and Z'-axis (hereinafter referred to as "XZ' plane"; the same applies to planes specified by other axes). The main surface is formed so that the direction parallel to the Y' axis becomes the thickness. As an example, when the upper surface 11A is viewed in plan, the outer edge of the crystal piece 11 is in a direction parallel to the X-axis (hereinafter referred to as “X-axis direction”; the same applies to directions parallel to other axes.). It has long sides that extend and short sides that extend in the Z′-axis direction.

The crystal vibrating element 10 using the AT-cut crystal blank 11 has high frequency stability over a wide temperature range. In the crystal vibrating element 10 using the AT-cut crystal blank 11, a thickness shear vibration mode is used as a main vibration. A different cut other than the AT cut may be applied to the cut angle of the crystal piece 11 . For example, BT cut, GT cut, SC cut, etc. may be applied.

When the upper surface 11A of the crystal piece 11 is viewed in plan, the crystal piece 11 has an excitation portion 17 where electromechanical energy conversion is performed, and a peripheral portion 18 located outside the excitation portion 17 . The excitation unit 17 is provided in a rectangular island shape and surrounded by a frame-shaped peripheral portion 18 . The excitation section 17 has an upper surface 17A and a lower surface 17B, and the peripheral section 18 has an upper surface 18A and a lower surface 18B. The upper surfaces 17A and 18A are part of the upper surface 11A of the crystal piece 11, and the lower surfaces 17B and 18B are parts of the lower surface 11B of the crystal piece 11. FIG.

The crystal blank 11 has a so-called mesa structure in which the excitation portion 17 is thicker than the peripheral portion 18 . The crystal blank 11 having the mesa structure can suppress vibration leakage from the crystal vibrating element 10 . Further, frequency fluctuation caused by external stress propagating to the excitation unit 17 can be suppressed. The crystal piece 11 has a double-sided mesa structure, and excitation portions 17 protrude from a peripheral portion 18 on both sides of the upper surface 11A and the lower surface 11B. A boundary region between the excitation portion 17 and the peripheral portion 18 has a tapered shape in which the thickness continuously changes. In other words, the surfaces connecting the upper surfaces 17A and 18A and the surfaces connecting the lower surfaces 17B and 18B of the excitation portion 17 and the peripheral portion 18 are uniformly inclined surfaces.

The structures of the excitation section 17 and the peripheral section 18 are not limited to those described above. For example, the excitation portion 17 and the peripheral portion 18 may each be formed in a strip shape over the entire width of the crystal piece 11 along the Z′-axis direction. Also, the boundary region between the excitation portion 17 and the peripheral portion 18 may have a stepped shape in which the change in thickness is discontinuous. The boundary region may have a convex structure in which the amount of change in thickness changes continuously, or a bevel structure in which the amount of change in thickness changes discontinuously. Further, the crystal blank 11 may have a so-called inverted mesa structure in which the thickness of the excitation portion 17 is smaller than the thickness of the peripheral portion 18 . The crystal piece 11 may have a flat plate shape in which the thickness of the excitation portion 17 and the thickness of the peripheral portion 18 are substantially equal.

The first excitation electrode 14 a and the second excitation electrode 14 b are provided in the central portion of the excitation section 17 . The first excitation electrode 14 a is provided on the upper surface 17 A of the excitation section 17 , and the second excitation electrode 14 b is provided on the lower surface 17 B of the excitation section 17 . The first excitation electrode 14 a and the second excitation electrode 14 b face each other with the excitation section 17 interposed therebetween, and are configured to be able to apply a voltage to the excitation section 17 .

The first extraction electrode 15 a and the second extraction electrode 15 b are provided from the excitation section 17 to the peripheral section 18 . The first extraction electrode 15 a is connected to the first excitation electrode 14 a on the upper surface 17 A of the excitation section 17 and connected to the first connection electrode 16 a on the peripheral section 18 . The second extraction electrode 15b is connected to the second excitation electrode 14b on the lower surface 17B of the excitation section 17 and to the second connection electrode 16b on the peripheral section 18 .

The first connection electrode 16 a and the second connection electrode 16 b are provided on the bottom surface 18 B of the peripheral portion 18 . The first connection electrode 16a and the second connection electrode 16b are arranged on the negative side of the X-axis direction (direction opposite to the direction of the arrow) with respect to the first excitation electrode 14a and the second excitation electrode 14b in the peripheral portion 18. located area. The first connection electrode 16a and the second connection electrode 16b are arranged in the Z'-axis direction, and the second connection electrode 16b is located on the negative side of the Z'-axis direction with respect to the first connection electrode 16a. The first connection electrode 16a is electrically connected to the first excitation electrode 14a through the first extraction electrode 15a. The second connection electrode 16b is electrically connected to the second excitation electrode 14b via the second extraction electrode 15b.

The first excitation electrode 14a, the first extraction electrode 15a, and the first connection electrode 16a are continuous and integrally formed. The same applies to the second excitation electrode 14b, the second extraction electrode 15b, and the second connection electrode 16b. The electrodes of these crystal vibrating elements 10 are conductive electrodes including, for example, a base layer made of a material with good adhesion to the crystal piece 11 and a surface layer made of a material with good chemical stability. It is a multilayer film. The underlying layer is, for example, a chromium (Cr) layer, and the outermost layer is, for example, a gold (Au) layer.

The base member 30 includes a substrate 31, a first electrode pad 33a and a second electrode pad 33b forming a pair of electrode pads, a first through electrode 34a and a second through electrode 34b forming a pair of through electrodes, and a 1 external electrode 35a to fourth external electrode 35d.

The base 31 is a plate-shaped insulator having an upper surface 31A and a lower surface 31B. The substrate 31 is, for example, a sintered material of insulating ceramics (alumina, etc.). It is preferable that the substrate 31 is made of a heat-resistant material from the viewpoint of suppressing the thermal stress acting on the crystal vibrating element 10 from the base member 30 due to thermal history such as reflow. The substrate 31 may be made of a material (such as crystal) having a coefficient of thermal expansion close to that of the crystal piece 11 .

The first electrode pad 33 a and the second electrode pad 33 b are provided on the upper surface 31 A of the base 31 . The first electrode pad 33 a and the second electrode pad 33 b are terminals for electrically connecting the crystal vibrating element 10 to the base member 30 . The first electrode pad 33a and the second electrode pad 33b are, for example, a conductive multilayer film including an Au layer on its surface.

The first through electrode 34a and the second through electrode 34b penetrate the base 31 in the Z'-axis direction. The first through electrode 34a electrically connects the first electrode pad 33a and the first external electrode 35a. The second through electrode 34b electrically connects the second electrode pad 33b and the second external electrode 35b.

The first to fourth external electrodes 35 a to 35 d are provided on the lower surface 31 B of the base 31 . The first external electrode 35a and the second external electrode 35b are terminals for electrically connecting the crystal resonator 1 to an external substrate. The third external electrode 35c and the fourth external electrode 35d are dummy electrodes to which, for example, electrical signals are not input/output. good.

The first conductive holding member 36a and the second conductive holding member 36b hold the crystal vibrating element 10 so that it can be excited. In other words, the first conductive holding member 36 a and the second conductive holding member 36 b hold the crystal vibrating element 10 so that the excitation section 17 does not contact the base member 30 and the lid member 40 . Also, the first conductive holding member 36 a and the second conductive holding member 36 b 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 connection electrode 16a, and the second conductive holding member 36b connects the second electrode pad 33b and the second connection electrode. 16b are electrically connected.

The first conductive holding member 36a and the second conductive holding member 36b are cured conductive adhesives containing thermosetting resin, photo-setting resin, or the like. A main component of the first conductive holding member 36a and the second conductive holding member 36b is, for example, silicone resin. The first conductive holding member 36a and the second conductive holding member 36b contain conductive particles, and metal particles containing silver (Ag), for example, are used as the conductive particles.

The main component of the first conductive holding member 36a and the second conductive holding member 36b is not limited to silicone resin as long as it is a curable resin, and may be, for example, epoxy resin or acrylic resin. Further, the conductivity of the first conductive holding member 36a and the second conductive holding member 36b is not limited to being imparted by silver particles, and may be imparted by other metals, conductive ceramics, conductive organic materials, and the like. may The main component of the first conductive holding member 36a and the second conductive holding member 36b may be a conductive polymer.

The lid member 40 forms an internal space that accommodates the crystal vibrating element 10 between itself and the base member 30 . The lid member 40 has a recess 49 that opens toward the base member 30 , and the internal space in this embodiment corresponds to the space inside the recess 49 . The lid member 40 has a flat top wall portion 41 and side wall portions 42 extending from the outer edge of the top wall portion 41 toward the base member 30 . The recessed portion 49 of the lid member 40 is formed by the ceiling wall portion 41 and the side wall portion 42 . The lid member 40 further has a flange portion 43 connected to the tip of the side wall portion 42 on the base member 30 side and extending outward along the upper surface 31A of the base 31 . When the upper surface 31</b>A of the base 31 is viewed from above, the flange portion 43 extends like a frame so as to surround the crystal vibrating element 10 .

The material of the lid member 40 is desirably a conductive material, more desirably a highly airtight metal material. Since the cover member 40 is made of a conductive material, the cover member 40 is provided with an electromagnetic shielding function that reduces the entry and exit 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 desirably a material having a coefficient of thermal expansion close to that of the base 31. For example, the coefficient of thermal expansion near room temperature is glass or ceramic, which can be used over a wide temperature range. It is a matching Fe--Ni--Co based alloy.

The joint member 50 is provided over the entire circumferences 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 plan, the first electrode pads 33a and the second electrode pads 33b are arranged inside the bonding member 50, and the bonding member 50 is provided so as to surround the crystal vibrating element 10. there is 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 .

The joining member 50 includes, for example, a metallized layer made of molybdenum (Mo) provided on the upper surface 31A of the base 31, and a gold-tin (Au—Sn)-based eutectic layer provided between the metallized layer and the flange portion 43. It is provided by a metal solder layer made of an alloy. Although the material of the bonding member 50 is not limited to the above, it preferably has low moisture permeability from the viewpoint of suppressing fluctuations in the frequency characteristics of the crystal oscillator 10, and more preferably has low gas permeability. Moreover, in order to electrically connect the lid member 40 to the ground potential via the joint member 50, it is desirable that the joint member 50 has conductivity.

The bonding member 50 is not limited to the metal bonding described above. The joining member 50 may be provided by, for example, a resin-based adhesive or a glass-based adhesive. When the joining member 50 is provided with an adhesive, the joining member 50 may be provided with a conductive adhesive or an insulating adhesive. Also, the base member 30 and the lid member 40 may be joined by seam welding.

The resin member 70 serves as a supply source of the resin film CT for covering the foreign matter DS present in the internal space. Specifically, the resin material scattered from the resin member 70 deposits on the inner wall of the internal space, that is, the surfaces of the crystal oscillator 10, the base member 30, the lid member 40, the bonding member 50, etc. exposed to the internal space, A resin film CT is formed on the surface. The position of the foreign matter DS covered with the resin film CT is fixed. For this reason, for example, even if a shock is applied to the crystal resonator 1 by being dropped or the like, or if the crystal resonator element 10 to which the foreign matter DS is attached is excited, the foreign matter DS may adhere to the crystal resonator element 10 or Falling off from the crystal vibrating element 10 is suppressed.

The resin member may be provided on at least one of the base member 30 and the lid member 40 in the internal space, and the resin member 70 is provided on the base member 30 . As shown in FIG. 3 , in plan view, the resin member 70 is provided in a region outside the crystal vibrating element 10 and does not interfere with the vibration of the crystal vibrating element 10 . The resin member 70 is spaced apart from the bonding member 50 and provided in a region between the crystal vibrating element 10 and the bonding member 50 in plan view. Further, the resin member 70 is separated from the first conductive holding member 36a and the second conductive holding member 36b.

The resin member 70 is made of, for example, a non-conductive resin material whose main component is silicone resin, epoxy resin, acrylic resin, or the like. The material of the resin member 70 is not limited to the above as long as the resin film CT can be supplied by heating. Raw materials of the resin film CT scattered from the resin member 70 are, for example, unreacted monomers, oligomers, etc. generated when the resin member 70 is provided, or low molecular weight polymers, oligomers, etc. generated by thermal decomposition of the resin member 70. . If the joint member 50 is made of resin, it is desirable that the heat resistance of the resin member 70 is lower than that of the joint member 50 . According to this, the raw material of the resin film CT can be supplied from the resin member 70 without impairing the sealing performance.

The resin member 70 includes four resin pieces 71,72,73,74. The resin piece 71 is positioned on the X-axis positive direction side with respect to the crystal resonator element 10 , the resin piece 72 is positioned on the X-axis negative direction side with respect to the crystal resonator element 10 , and the resin piece 73 is positioned with respect to the crystal resonator element 10 . , and the resin piece 74 is positioned on the Z′-axis negative direction side with respect to the crystal vibrating element 10 . That is, in a plan view, the resin pieces 71 and 72 are adjacent to the short sides of the crystal oscillator 10 that face each other, and the resin pieces 73 and 74 are adjacent to the long sides of the crystal oscillator 10 that face each other. adjacent to each other.

In order to reduce unevenness of the resin film CT, the plurality of resin pieces 71 to 74 serving as the supply source of the resin film CT are evenly arranged around the crystal vibrating element 10 . In other words, the intervals between adjacent resin pieces among the plurality of resin pieces 71 to 74 are substantially equal in the circumferential direction surrounding the crystal vibrating element 10 in plan view. Specifically, the distance between the resin piece 71 and the resin piece 73, the distance between the resin piece 73 and the resin piece 72, the distance between the resin piece 72 and the resin piece 74, and the distance between the resin piece 74 and the resin piece 71 are approximately equal to each other. Furthermore, in order to reduce the unevenness of the resin film CT, the resin pieces 71 and 72 are provided at the central portion of the crystal oscillator 1 in the Z′-axis direction, and the resin pieces 73 and 74 are each provided on the crystal unit. It is provided in the central portion of the vibrator 1 in the X-axis direction.

Note that the number of resin pieces included in the resin member 70 is not limited to four. The number of resin pieces may be three or less, or five or more. However, at least one of the resin pieces is desirably provided on the opposite side of the crystal vibrating element 10 from the conductive holding members 36a and 36b. For example, the resin member 70 may consist of only the resin piece 71 shown in FIG. 3, or may include the resin pieces 71, 73, and 74 except for the resin piece 72 shown in FIG. In these cases, by using the first conductive holding member 36a and the second conductive holding member 36b as the supply source of the resin film CT, the resin pieces 72 are omitted, thereby saving space and increasing the capacity of the resin film CT. Unevenness can be reduced. The resin member 70 may include resin pieces arranged near the corners of the crystal vibrating element 10 .

Next, a method for manufacturing the crystal resonator 1 according to the first embodiment will be described with reference to FIG. FIG. 4 is a flow chart schematically showing a method for manufacturing a crystal resonator according to the first embodiment.

First, the base member 30 is prepared (S10).

The base member 30 is formed by sintering ceramic powder, for example. As an example, a through hole is formed in an alumina green sheet, and the through hole is filled with an electrode material. Next, a metal film is printed on the green sheet (screen printing, inkjet printing, gravure printing, flexographic printing, etc.), and the green sheet, electrode material and metal film are sintered. As a result, the alumina green sheet becomes the substrate 31, the electrode material becomes the through electrodes 34a and 34b, and the metal film becomes the metallized layers of the joining member 50, the electrode pads 33a and 33b, and the external electrodes 35a to 35d. The method of forming a metal film is not limited to the above printing method, and various coating methods (casting, dispensing, etc.), and various wet plating methods (electroless plating, hot dipping, electroplating, etc.). It may be formed by a wet process.

The substrate 31 may be formed by a wafer cut from an ingot. The metal film may be formed by dry processes such as PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition). At least part of each of the metallized layers 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 sheets.

Next, the lid member 40 is prepared (S20).

The lid member 40 is formed, for example, by pressing a metal plate. As an example, a metal plate made of an Fe--Ni--Co alloy is prepared. Next, the metal plate is pressed by a punch to be deformed into a concave shape, and the shapes of the top wall portion 41, the side wall portion 42 and the flange portion 43 are formed.

The lid member 40 may be formed by providing a concave portion 49 by etching a ceramic substrate, a crystal substrate, or the like.

Next, the crystal oscillator 10 is mounted (S30).

First, a crystal oscillator is prepared. A quartz crystal is sliced to form a quartz wafer. The crystal wafer may be appropriately subjected to necessary processing such as planarization processing such as chemical mechanical polishing, cleaning processing using a rinse liquid, and the like. Next, a portion of the crystal wafer is removed to form the contours of a plurality of interconnected crystal pieces. 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 structure. The removal process is performed, for example, by etching using photolithography, but may be performed by other processing methods such as plasma CVM (Chemical Vaporization Machining).

Next, a metal film is provided on the surface of each of the plurality of crystal pieces, a portion of the metal film is removed by etching using photolithography, and an electrode is formed from the metal film. The method for forming the electrodes is not limited to etching, and the electrodes may be formed by lift-off.

Finally, the crystal vibrating element is singulated. A thin portion, which is thinner than the surrounding area, is formed in the portion where the multiple crystal pieces are connected, and when bending stress is applied, the thin portion becomes the starting point of a crack, and the portion that connects the multiple crystal pieces is broken. be. The thin portion is formed, for example, by using etching in a step of forming the contours of the plurality of crystal pieces or a step of processing each of the plurality of crystal pieces into a mesa structure. The thinned portion may be formed by a scribing tool. Note that the crystal vibrating element may be separated into individual pieces by cutting with a laser cutter, a dicing saw, or the like.

Next, the crystal vibrating element 10 is bonded to the base member 30 . First, prepare a conductive adhesive paste containing a thermosetting resin. Next, the base member 30 is placed on a hot plate that has not been heated. Next, a conductive adhesive paste is applied onto each of the first electrode pads 33 a and the second electrode pads 33 b of the base member 30 . Next, the crystal oscillator 10 is placed on the conductive adhesive paste so that the tip of the crystal oscillator 10 does not come into contact with the base member 30 . Next, the conductive adhesive paste is cured by heating with a hot plate to form the first conductive holding member 36a and the second conductive holding member 36b. Thereby, the first electrode pads 33a and the second electrode pads 33b of the base member 30 and the first connection electrodes 16a and the second connection electrodes 16b of the crystal vibrating element 10 are respectively joined.

Note that preheating may be performed to adjust the viscosity of the conductive adhesive paste before placing the crystal oscillator 10 on the conductive adhesive paste. Moreover, the resin composition of the conductive adhesive paste is not limited to a thermosetting resin composition, and may include a light (UV) curable resin composition. In this case, step S40 may include a step of irradiating the conductive adhesive paste with light (UV).

In the step of providing the resin member 70, for example, first, a non-conductive resin-based adhesive paste containing a thermosetting resin is applied to the base member 30 before mounting the crystal vibrating element 10 thereon. Next, the conductive adhesive paste is cured by heating to form the resin member 70 . The heat treatment for curing the resin-based adhesive paste that forms the resin member 70 is performed simultaneously with the heat treatment for curing the conductive adhesive paste that forms the first conductive holding member 36a and the second conductive holding member 36b.

The heat treatment for curing the resin member 70 may be performed before or after the heat treatment for curing the first conductive holding member 36a and the second conductive holding member 36b. Alternatively, the resin member 70 may be provided after the crystal vibrating element 10 is mounted on the base member 30 . The resin member 70 may be made of a resin-based adhesive paste containing a photocurable resin.

Next, the crystal vibrating element 10 is housed (S40).

First, the lid member 40 is placed in the storage tray. The storage tray is provided with a bottomed opening in which the lid member 40 can be stored almost without gaps. The top wall upper surface 41A of the top wall portion 41 is directed toward the bottom of the opening, and the lid member is accommodated in the opening.

Next, metal solder is provided on the flange lower surface 43B of the flange portion 43 . The metal solder is a gold-tin (Au—Sn)-based eutectic alloy. Note that 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 oscillator 10 is mounted is housed in the opening with the crystal oscillator 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 base member 30 and the lid member 40 are joined together (S50).

The metal solder is heated to soften, and the softened metal solder is cooled to solidify. The solidified metal solder forms the joint member 50 together with the metallized layer of the base member 30, joins the base member 30 and the lid member 40, and seals the recess 49 corresponding to the internal space. The heat treatment in step S50 corresponds to an example of the "first heat treatment" according to the present invention.

Next, a resin film CT is formed (S60).

The sealed crystal oscillator 1 is heated, and the raw material for the resin film CT is supplied from the resin member 70 . Specifically, the raw material of the resin film CT is scattered from the resin member 70 and deposited on the exposed surface of the internal space to form the resin film CT. The resin film CT covers the crystal vibrating element 10 , the base member 30 , the lid member 40 and the bonding member 50 . The heat treatment in step S60 corresponds to an example of the "second heat treatment" according to the present invention.

Although the first heat treatment and the second heat treatment are different heat treatments in the present embodiment, the first heat treatment and the second heat treatment may be the same heat treatment. In other words, the base member 30 and the lid member 40 may be bonded and the resin film CT may be formed in one heat treatment.

Finally, the crystal oscillator 1 is taken out from the storage tray.

The order of the step S10 of preparing the base member 30, the step S20 of preparing the lid member 40, and the step of preparing the crystal vibrating element 10 is not limited to the above. Step S<b>10 may be performed after step S<b>20 or after the step of preparing crystal oscillator 10 . Step S<b>20 may be performed after the step of preparing crystal oscillator 10 .

Moreover, the resin-based adhesive paste that forms the resin member 70 may be cured after the step S40 of housing the crystal vibrating element 10 . For example, the heat treatment for curing the bonding member 50 in the step S50 of bonding the base member 30 and the lid member 40 may be used to heat and cure the resin-based adhesive paste that forms the resin member 70 . In such a case, the resin film CT may be formed in the step of curing the resin member 70 .

As described above, in the first embodiment, the base member 30 is provided with the resin member 70 that serves as the supply source of the resin film CT for covering the foreign matter DS. According to this, the adhesion of the foreign matter DS to the crystal vibrating element 10 or the falling off from the crystal vibrating element 10 is suppressed, thereby suppressing the frequency fluctuation.

Since the resin member 70 is provided in the region outside the crystal vibrating element 10 in plan view, deterioration of vibration characteristics due to interference between the crystal vibrating element 10 and the resin member 70 does not occur.

The resin member 70 is composed of a plurality of resin pieces 71 to 74, and since the plurality of resin pieces 71 to 74 are evenly arranged around the crystal vibrating element 10 in plan view, unevenness of the resin film CT can be reduced. .

At least one of the plurality of resin pieces 71 to 74 is provided on the opposite side of the crystal vibrating element 10 from the conductive holding members 36a and 36b in plan view. Therefore, even if the resin pieces on the side of the conductive holding members 36a and 36b in the crystal vibrating element 10 are omitted in plan view, the conductive holding members 36a and 36b can also be used as supply sources for the resin film CT. CT unevenness can be reduced. In other words, frequency fluctuation can be suppressed while downsizing is achieved by partly omitting the resin pieces.

The configuration of a crystal oscillator 1 according to another embodiment of the present invention will be described below. In addition, in the following embodiment, the description of matters common to the first embodiment will be omitted, and only the points of difference will be described. In particular, similar actions and effects due to similar configurations will not be mentioned successively.

<Second embodiment>
The configuration of the crystal resonator 2 according to the second embodiment will be described with reference to FIG. FIG. 5 is a cross-sectional view schematically showing the configuration of a crystal oscillator according to the second embodiment.

In this embodiment, the resin member 270 is provided on the ceiling wall portion 41 of the lid member 40 . Note that the resin member 270 may be provided on the side wall portion 42 of the lid member 40 .

<Third Embodiment>
The configuration of the crystal resonator 3 according to the second embodiment will be described with reference to FIG. FIG. 6 is a plan view schematically showing the configuration of a base member and a crystal vibrating element according to the third embodiment.

In plan view, the resin member 370 is provided in a frame shape surrounding the crystal vibrating element 10 . The shape of the resin member 370 is not limited to a frame shape as long as the resin member 370 is provided along the crystal vibrating element 10 or the bonding member 50 in the region surrounding the crystal vibrating element 10 . For example, the resin member 370 may be provided in an L shape along the corners of the crystal vibrating element 10, and may be formed in a U shape on the opposite side of the crystal vibrating element 10 from the side of the conductive holding members 36a and 36b. may be provided.

Some or all of the embodiments of the present invention are described below. In addition, the present invention is not limited to the following additional remarks.

According to one aspect of the present invention, there are provided: a crystal resonator element having a piezoelectric piece and an excitation electrode configured to apply a voltage to the piezoelectric piece; a base member on which the crystal resonator element is mounted; the crystal resonator element and the base member; a conductive holding member that electrically connects the base member, a cover member that accommodates the crystal oscillator in an internal space provided between the base member and the base member, and a joining member that joins the base member and the cover member; A crystal oscillator is provided in which at least one of the base member and the lid member in the internal space is provided with a resin member serving as a supply source of a resin film for covering foreign matter present in the internal space.

As one aspect, in plan view, the resin member is provided in a region outside the crystal vibrating element.

As one aspect, the resin member includes a plurality of resin pieces.

As one aspect, in plan view, the plurality of resin pieces are evenly arranged around the crystal vibrating element.

As one mode, in a plan view, at least one of the plurality of resin pieces is provided on the opposite side of the crystal vibrating element to the conductive holding member.

As one aspect, in a plan view, the resin member is provided in an L-shape, a U-shape, or a frame shape surrounding at least a portion of the crystal vibrating element.

As one aspect, the resin member is spaced apart from the joining member.

According to another aspect of the present invention, preparing a base member; preparing a lid member; providing a resin member in at least one of the base member and the lid member; Mounting, mounting one of the base member and the lid member on the other, and covering the foreign matter present in the interior space by using the resin member accommodated in the interior space between the base member and the lid member as a supply source. and forming a resin film to form a crystal oscillator.

One aspect includes a first heat treatment for heating a joining member between a base member and a lid member, and a second heat treatment for forming a resin film using a resin member as a supply source.

As one aspect, the first heat treatment and the second heat treatment are the same heat treatment.

As one aspect, the first heat treatment and the second heat treatment are different heat treatments.

It should be noted that the embodiments according to the present invention are not limited to crystal resonators, and can also be applied to other piezoelectric resonators (Piezoelectric Resonator Unit). Piezoelectric pieces suitably used in the piezoelectric vibrator according to this embodiment include, for example, piezoelectric ceramics such as lead zirconate titanate (PZT) and aluminum nitride, and piezoelectric single crystals such as lithium niobate and lithium tantalate. However, it is not limited to these and can be selected as appropriate.

Embodiments according to the present invention are applicable to any device, such as a timing device, a sound generator, an oscillator, a load sensor, or the like, which performs electromechanical energy conversion by means of a piezoelectric effect, without particular limitation.

As described above, according to one aspect of the present invention, it is possible to provide a piezoelectric vibrator capable of suppressing frequency fluctuation and a method for manufacturing the same.

In addition, the embodiment described above is intended to facilitate understanding of the present invention, and is not intended to limit and interpret the present invention. The present invention may be modified/improved without departing from its spirit, and the present invention also includes equivalents thereof. In other words, any embodiment appropriately modified in design by a person skilled in the art is also included in the scope of the present invention as long as it has the features of the present invention. For example, each element provided in each embodiment and its arrangement, material, condition, shape, size, etc. are not limited to those illustrated and can be changed as appropriate. Moreover, each element provided in each embodiment can be combined as long as it is technically possible, and a combination thereof is also included in the scope of the present invention as long as it includes the features of the present invention.

1 ... crystal oscillator,
10 ... crystal oscillator,
11... crystal piece,
14a, 14b... excitation electrodes,
15a, 15b... Extraction electrodes,
16a, 16b ... connection electrodes,
17 ... excitation unit,
18... Peripheral part,
30 ... Base member,
36a, 36b... Conductive holding member 40... Lid member,
50... Joining member 70... Resin member,
71, 72, 73, 74... resin pieces,
CT: resin film,
DS: foreign matter.

Claims (12)

a piezoelectric vibration element having a piezoelectric piece and an excitation electrode configured to apply a voltage to the piezoelectric piece;
a base member on which the piezoelectric vibration element is mounted;
a conductive holding member that electrically connects the piezoelectric vibrating element and the base member;
a lid member that accommodates the piezoelectric vibrating element in an internal space provided between the base member;
a joining member that joins the base member and the lid member;
with
In the internal space, at least one of the base member and the lid member is provided with a resin member serving as a supply source of a resin film for covering foreign matter present in the internal space.
piezoelectric vibrator. In plan view, the resin member is provided in a region outside the piezoelectric vibrating element,
The piezoelectric vibrator according to claim 1. The resin member includes a plurality of resin pieces,
The piezoelectric vibrator according to claim 2. In plan view, the plurality of resin pieces are evenly arranged around the piezoelectric vibrating element,
The piezoelectric vibrator according to claim 3. In plan view, at least one of the plurality of resin pieces is provided on a side of the piezoelectric vibrating element opposite to the conductive holding member,
The piezoelectric vibrator according to claim 3 or 4. In plan view, the resin member is provided in an L-shape, a U-shape, or a frame shape surrounding at least a portion of the piezoelectric vibrating element.
The piezoelectric vibrator according to claim 2. The resin member is separated from the joining member,
The piezoelectric vibrator according to any one of claims 1 to 6. The piezoelectric vibrating element is a crystal vibrating element using a crystal piece as the piezoelectric piece,
The piezoelectric vibrator according to any one of claims 1 to 7. providing a base member;
providing a lid member;
providing a resin member on at least one of the base member and the lid member;
mounting a piezoelectric vibration element on the base member;
mounting one of the base member and the lid member on the other;
forming a resin film to cover foreign matter present in the internal space using the resin member accommodated in the internal space between the base member and the lid member as a supply source;
including,
A method for manufacturing a piezoelectric vibrator. a first heat treatment for heating a joining member between the base member and the lid member;
a second heat treatment for forming the resin film using the resin member as a supply source;
10. The method of manufacturing the piezoelectric vibrator according to claim 9. The first heat treatment and the second heat treatment are the same heat treatment,
11. The method of manufacturing the piezoelectric vibrator according to claim 10. The first heat treatment and the second heat treatment are different heat treatments,
11. The method of manufacturing the piezoelectric vibrator according to claim 10.

Images