JP2016181879A - Method of manufacturing piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a piezoelectric device which can keep joining strength of a cover body to a package, and improve hermetic sealing properties, while suppressing occurrence of a crack on the package.SOLUTION: A method of manufacturing a piezoelectric device includes: a piezoelectric element mounting step for mounting a piezoelectric element 120 on an electrode pad 111 via a conductive adhesive 140; a cover body placing step for placing a cover body 130 on a package 110 via a joining member 140; a vacuum step for storing the package 110 in which the cover body 130 is placed on a chamber portion of a sealing device, and making the inside of the chamber portion into a vacuum atmosphere; and a cover body joining step for raising temperature in the chamber portion of the sealing device to a first reach temperature T1, lowering that to a second reach temperature T2 after reaching the first reach temperature T1, injecting nitrogen into the chamber portion of the sealing position while the temperature reaches the second reach temperature T2, and further lowering the temperature to join the cover body 130 to the package 110 via a joining member 131.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing a piezoelectric device used in electronic equipment and the like.

In the conventional method of manufacturing a piezoelectric device, a conductive adhesive is applied on an electrode pad provided on the upper surface of a package, and a piezoelectric element is placed on the conductive adhesive, and the conductive adhesive is heated and cured. There is known a manufacturing method including a step of conducting and fixing an electrode pad and a piezoelectric element and a step of bonding a lid and a package via a bonding member (for example, see Patent Document 1). Also,
When joining a lid and a package via a joining member, it is known to apply heat to the joining member while bringing a weighting jig into contact with the lid or the package (for example, see Patent Document 2). .

JP 2007-235340 A JP 2007-005457 A

  In the conventional method for manufacturing a piezoelectric device described above, when the lid and the package are joined via the joining member, the weight jig is brought into contact with the lid or the package. There is a risk of causing cracks in the package due to the contact. In addition, due to variations in the load applied to the package due to the inclination of the package arranged in the alignment jig, the bonding member does not melt, and the bonding strength between the lid and the package is lowered, thereby hermetically sealing There was a possibility that the property could not be maintained.

  The present invention has been made in view of the above problems, and the object thereof is to maintain the bonding strength between the lid and the package and improve the hermetic sealing property while suppressing the occurrence of cracks in the package. A method for manufacturing a piezoelectric device is provided.

  The piezoelectric device manufacturing method of the present invention includes a piezoelectric element mounting step of mounting a piezoelectric element on an electrode pad provided on the upper surface of the package via a conductive adhesive, and a bonding member on the package so as to cover the piezoelectric element. A lid placing step for placing the lid on, a vacuum step for accommodating the package on which the lid is placed in the chamber portion of the sealing device and making the inside of the chamber portion a vacuum atmosphere, and a chamber for the sealing device Raise the temperature in the part until it reaches the first ultimate temperature, reach the first ultimate temperature, lower it to the second ultimate temperature, and inject nitrogen into the chamber part of the sealing device at the second ultimate temperature, And a lid body joining step for joining the lid body to the package via the joining member by further lowering the temperature.

  According to the piezoelectric device manufacturing method of the present invention, the piezoelectric element mounting step of mounting the piezoelectric element on the electrode pad provided on the upper surface of the package via the conductive adhesive, and the bonding to the package so as to cover the piezoelectric element A lid placing step for placing the lid through the member, a vacuum step for accommodating the package on which the lid is placed in the chamber portion of the sealing device, and making the inside of the chamber a vacuum atmosphere, Raise the temperature in the chamber part until it reaches the first ultimate temperature, and after reaching the first ultimate temperature, lower it to the second ultimate temperature, and in the state of reaching the second ultimate temperature, inside the chamber part of the sealing device A lid joining step of joining the lid to the package via the joining member by injecting nitrogen and further lowering the temperature. By doing so, nitrogen is injected into the chamber portion of the sealing device in a state where the second ultimate temperature is reached, so that the package or the lid is pressurized with nitrogen. Therefore, it is not necessary to bring the weight jig into contact with the package or the lid, and it is possible to suppress the generation of cracks in the package. In addition, even if there is an inclination of the package arranged in the alignment jig, by introducing nitrogen, the package is uniformly loaded, so that the joining member is melted by suppressing the sealing variation, By improving the bonding strength between the lid and the package, the hermetic sealability can be improved.

It is a disassembled perspective view which shows the piezoelectric device formed with the manufacturing method of the piezoelectric device which concerns on embodiment of this invention. It is AA sectional drawing of FIG. (A) is sectional drawing which shows the state which apply | coated the electroconductive adhesive of the piezoelectric element mounting process of the manufacturing method of the piezoelectric device which concerns on embodiment of this invention, (b) concerns on embodiment of this invention. It is sectional drawing which shows the state which mounted the piezoelectric element of the piezoelectric element mounting process of the manufacturing method of a piezoelectric device, (c) is a cross section which shows the cover body mounting process of the manufacturing method of the piezoelectric device which concerns on embodiment of this invention. FIG. It is a graph which shows the temperature and the degree of vacuum in the chamber part of the sealing device before joining after joining, when joining a lid. It is the schematic of the sealing device used with the manufacturing method of the piezoelectric device which concerns on embodiment of this invention.

(Piezoelectric device)
The piezoelectric device in this embodiment includes a package 110 and a piezoelectric element 120 joined to the package 110 as shown in FIGS. 1 and 2. The package 110 has a recess K surrounded by the upper surface of the substrate 110a and the inner surface of the frame 110b. Such a piezoelectric device is used to output a reference signal used in an electronic device or the like.

  The substrate 110a has a rectangular shape and functions as a mounting member for mounting the piezoelectric element 120 mounted on the upper surface. A pair of electrode pads 111 for mounting the piezoelectric element 120 is provided on the upper surface of the substrate 110a.

In addition, external terminals 112 are provided at the four corners of the lower surface of the substrate 110a. Further, two of the four external terminals 112 are electrically connected to the piezoelectric element 120. In addition, the pair of external terminals 112 that are electrically connected to the piezoelectric element 120 are provided to be positioned diagonally on the lower surface of the substrate 110a.

  The substrate 110a is made of an insulating layer made of a ceramic material such as alumina ceramic or glass-ceramic. The substrate 110a may be one using an insulating layer or may be a laminate of a plurality of insulating layers. A wiring pattern (not shown) for electrically connecting the electrode pads 111 provided on the upper surface of the frame 110b and the external terminals 112 provided on the lower surface of the substrate 110a on the surface and inside of the substrate 110a. And via conductors (not shown).

  The frame 110b is disposed on the upper surface of the substrate 110a, and is for forming the recess K on the upper surface of the substrate 110a. The frame 110b is made of a ceramic material such as alumina ceramics or glass-ceramics, and is formed integrally with the substrate 110a.

  The electrode pad 111 is for mounting the piezoelectric element 120. A pair of electrode pads 111 are provided on the upper surface of the substrate 110a, and are provided adjacent to each other along one side of the inner periphery of the substrate 110a inside the frame 110b.

  The external terminal 112 is used for bonding to a mounting pad (not shown) on an external mounting substrate such as an electric device. The external terminals 112 are provided at the four corners of the lower surface of the substrate 110a. At least one of the external terminals 112 is electrically connected to the sealing conductor pattern 113 via a via conductor (not shown). In addition, at least one of the external terminals 112 is connected to a mounting pad connected to a ground potential that is a reference potential on a mounting substrate such as an electronic device. Thereby, the lid 130 bonded to the sealing conductor pattern 113 is connected to the external terminal 112 having the ground potential. Therefore, the shielding performance in the recess K by the lid 130 is improved.

  The sealing conductor pattern 113 plays a role of improving the wettability of the bonding member 131 when bonded to the lid 130 via the bonding member 131. The sealing conductor pattern 113 is electrically connected to at least one of the external terminals 112 via a via conductor (not shown). The sealing conductor pattern 113 is formed to have a thickness of, for example, 10 to 25 μm by sequentially applying nickel plating and gold plating on the surface of the conductor pattern made of, for example, tungsten or molybdenum so as to surround the upper surface of the frame 110b in an annular shape. Has been.

  Here, a method for manufacturing the substrate 110a and the frame 110b will be described. When the substrate 110a and the frame 110b are made of alumina ceramics, first, a plurality of ceramic green sheets obtained by adding and mixing an appropriate organic solvent or the like to a predetermined ceramic material powder is prepared. In addition, a predetermined conductor paste is applied to the surface of the ceramic green sheet or a through-hole previously punched by punching the ceramic green sheet by screen printing or the like. Further, these green sheets are laminated and press-molded and fired at a high temperature. Finally, it is produced by applying nickel plating, gold plating, silver palladium, or the like to predetermined portions of the conductor pattern, specifically, the portions to be the electrode pads 111, the external terminals 112, and the sealing conductor pattern 113. Moreover, the conductor paste is comprised from the sintered compact etc. of metal powders, such as tungsten, molybdenum, copper, silver, or silver palladium, for example.

  As shown in FIGS. 1 and 2, the piezoelectric element 120 is bonded onto the electrode pad 111 via a conductive adhesive 140. The piezoelectric element 120 plays a role of oscillating a reference signal of an electronic device or the like by stable mechanical vibration and a piezoelectric effect.

  Further, as shown in FIGS. 1 and 2, the piezoelectric element 120 has a structure in which an excitation electrode 122 and an extraction electrode 123 are attached to the upper surface and the lower surface of the crystal base plate 121, respectively. . The excitation electrode 122 is formed by depositing and forming a metal in a predetermined pattern on each of the upper surface and the lower surface of the quartz base plate 121. The excitation electrode 122 includes a first excitation electrode 122a on the upper surface and a second excitation electrode 122b on the lower surface. The extraction electrode 123 extends from the excitation electrode 122 toward one side of the crystal base plate 121. The extraction electrode 123 includes a first extraction electrode 123a on the upper surface and a second extraction electrode 123b on the lower surface. The first extraction electrode 123 a is extracted from the first excitation electrode 122 a and is provided so as to extend toward one side of the crystal base plate 121. The second extraction electrode 123 b is extracted from the second excitation electrode 122 b and is provided so as to extend toward one side of the crystal base plate 121. That is, the extraction electrode 123 is provided in a shape along the long side or the short side of the quartz base plate 121. In the present embodiment, one end of the piezoelectric element 120 connected to the first electrode pad 111a and the second electrode pad 111b is a fixed end connected to the upper surface of the substrate 110a, and the other end is between the upper surface of the substrate 110a. The piezoelectric element 120 is fixed on the substrate 110a by a cantilevered support structure with a free end.

  Here, the operation of the piezoelectric element 120 will be described. In the piezoelectric element 120, when an alternating voltage from the outside is applied from the extraction electrode 123 to the crystal base plate 121 via the excitation electrode 122, the crystal base plate 121 is excited in a predetermined vibration mode and frequency. ing.

  Here, a method for manufacturing the piezoelectric element 120 will be described. First, the piezoelectric element 120 is cut from the artificial crystalline lens at a predetermined cut angle to reduce the thickness of the outer periphery of the crystal base plate 121, and the central portion of the crystal base plate 121 is thicker than the outer peripheral portion of the crystal base plate 121. The bevel processing provided is performed. The piezoelectric element 120 is manufactured by forming the excitation electrode 122 and the extraction electrode 123 by depositing a metal film on both main surfaces of the quartz base plate 121 by photolithography, vapor deposition, or sputtering. Is done.

  The lid 130 is for hermetically sealing the recess K in a vacuum state or the recess K filled with nitrogen gas or the like. Specifically, the lid body 130 is a joining member provided on the upper surface of the frame body 110b and the lower surface of the lid body 130 in a nitrogen atmosphere or a vacuum atmosphere. 131 is melt-bonded by applying heat. By doing so, the sealing lid 130 is joined to the upper surface of the frame 110b.

  The joining member 131 is used to join the lower surface of the lid 130 and the outer peripheral edge of the upper surface of the frame 110b. As shown in FIG. 2, the joining member 131 is provided from the lower surface of the lid 130 to the outer peripheral edge on the frame 110 b. The glass bonding member 131 is made of, for example, low melting glass or lead oxide glass containing vanadium which is a glass that melts at 300 to 400 ° C. Glass is pasty with a binder and a solvent added, and is melted and then solidified to adhere to other members. The joining member 131 is provided, for example, by applying glass frit paste along the outer peripheral edge of the frame 110b by screen printing and drying. Further, when the joining member 131 is printed on the upper surface of the frame 110b, the joining member 131 is printed in an annular shape so that the joining members 131 overlap the four corners of the frame 110b. Therefore, the thickness of the bonding member 131 at the four corners is provided to be thicker than the thickness of other portions where the bonding member 131 is provided. The composition of the lead oxide glass is composed of lead oxide, lead fluoride, titanium dioxide, niobium oxide, bismuth oxide, boron oxide, zinc oxide, ferric oxide, copper oxide and calcium oxide. Moreover, the thickness of the joining member 131 in the vertical direction is 10 to 50 μm. By using this thickness, the hermetic sealability in the recess K can be maintained.

(Sealing device)
As shown in FIG. 5, the sealing device includes a chamber portion 11, a pedestal portion 12 for placing and fixing a conveyance jig containing a package 110 in the chamber portion 11, a xenon lamp, a halogen lamp, or the like. A heat source unit 13, a vacuum exhaust unit 14 for evacuating the chamber unit 11, a nitrogen supply unit 15 for creating a nitrogen atmosphere in the chamber unit 11, a temperature, a degree of vacuum, and a nitrogen flow rate in the chamber unit It is comprised by the control part 16 for controlling. The sealing device includes a chamber portion 11 that can keep the inside airtight by closing the door. The chamber portion 11 includes a pedestal portion 12 that holds a plurality or a plurality of piezoelectric devices in which a lid body 130 is arranged via a bonding member 131 of a package 110 in which a crystal element 120 is mounted in a recess K. ing.

  The pedestal portion 12 is provided in the chamber portion 11 and is introduced from a carry-in door (not shown), and after the lid is joined to the package, it is taken out from the carry-out door (not shown). . The pedestal unit 12 has a temperature detection unit including a temperature sensor configured with a thermocouple or the like for detecting the temperature in the chamber unit 11.

  The heat source part 13 is for raising the temperature in the chamber part 11. The heat source unit 13 is provided outside so as to be in contact with the chamber unit 11, and transmits heat into the chamber unit via the chamber unit 11. The heat source unit 13 is configured as a halogen lamp or a xenon lamp. A xenon lamp is a bulb in which a cathode and an anode are arranged inside. The xenon lamp condenses the position of the highest luminance of the light emitting part at the focal point of the condensing mirror and emits it to the focal point from the exit end of the optical fiber. is there. Similarly, the halogen lamp is provided with a tungsten filament in a bulb and sealed with a halogen gas. The power supply unit is composed of an AC power supply. The power supply unit AC / DC converts the voltage of the drive current supplied from the AC power supply, and stably applies the drive current to the heat source unit 13 with a constant voltage.

  In the chamber part 11, the gas detection part 18 which consists of a gas sensor which detects the degree of vacuum or gas concentration in the chamber part 11, such as a pressure sensor and an oxygen sensor, is provided. The chamber 11 is connected to a vacuum exhaust unit 14 such as a vacuum pump and a nitrogen supply unit 15. The temperature detection unit 17, the gas detection unit 18, the vacuum exhaust unit 14, and the nitrogen supply unit 15 are connected to the control unit 16. As a result, the inside of the chamber can be evacuated while monitoring the gas pressure or nitrogen concentration in the chamber.

(Production method)
Next, a method for manufacturing a piezoelectric device according to an embodiment of the present invention will be described with reference to FIGS. In the method for manufacturing a piezoelectric device according to the present embodiment, the piezoelectric element 120 is placed on the electrode pad 111 provided on the package 110 via the conductive adhesive 140, and the conductive adhesive 140 is cured, whereby the crystal element 120. A piezoelectric element mounting step for mounting the lid body, a lid body placing step for placing the lid body 130 on the package 110 via the bonding member 131 so as to cover the piezoelectric element 120, and a chamber of the sealing device (not shown). The package 110 in which the lid body 130 is placed is accommodated in the part, the vacuum process for making the inside of the chamber part into a vacuum atmosphere, and the temperature in the chamber part of the sealing device is raised until the first attainment temperature T1 is reached. After reaching the temperature T1, the temperature is lowered to the second ultimate temperature T2, nitrogen is injected into the chamber portion of the sealing device at the second ultimate temperature T2, and the temperature is further lowered. It includes lid bonding step of bonding the lid 130 to the package 110 via member 131.

(Piezoelectric element mounting process)
In the piezoelectric element process, as shown in FIGS. 3A and 3B, a conductive adhesive 140 is applied to the electrode pad 111 provided on the upper surface of the substrate 110 a, and a piezoelectric material is applied on the conductive adhesive 140. This is a step of mounting the piezoelectric element 120 by disposing the element 120 and curing the conductive adhesive 140. In the piezoelectric element mounting step, the piezoelectric element 120 is mounted on the conductive adhesive 140 such that the lead electrode 123 of the piezoelectric element 120 and the conductive adhesive 140 applied on the electrode pad 111 of the package 110 face each other. Put. Next, in a state where the package 110 is accommodated in the internal space of the curing annealing furnace in the air atmosphere or nitrogen atmosphere, the conductive adhesive 140 is heated and cured, and the electrode pad 111 and the piezoelectric element 120 are conductively fixed.

  The conductive adhesive 140 includes conductive powder as a conductive filler in a binder such as silicone resin. Examples of the conductive powder include aluminum (Al), molybdenum (Mo), tungsten ( W), platinum (Pt), palladium (Pd), silver (Ag), titanium (Ti), nickel (Ni), nickel iron (NiFe), or any combination thereof is used. Yes. The inner diameter of the nozzle corresponds as appropriate depending on the particle size of the conductive powder.

  A curing annealing furnace (not shown) includes a furnace body, a heating unit, a supply unit, and a control unit. The furnace body has an internal space and serves to store the package 110. The heating unit plays a role of heating the internal space to a predetermined temperature. For example, a halogen lamp or a xenon lamp is used as the heating unit. The supply unit serves to supply gas to the internal space. For example, nitrogen is used as the gas. The control unit controls the temperature and oxygen concentration of the internal space of the furnace body, the temperature increase rate of the heating unit, and the gas supply amount of the supply unit.

(Cover body placing process)
The lid placing step is a step of placing the lid 130 on the package 110 via the bonding member 131 such that the lid 130 covers the piezoelectric element 120 as shown in FIG. In the lid placing step, as shown in FIG. 3C, the lid 130 is sucked by the suction nozzle NZ of the lid mounting apparatus and placed on the upper surface of the frame 110 b of the package 110 via the bonding member 131. Has been.

(Vacuum process)
The vacuum process is a process in which the package 110 on which the lid 130 is placed is accommodated in the chamber part 11 (see FIG. 5) of the sealing device, and the inside of the chamber part 11 is made a vacuum atmosphere. Further, the inside of the chamber unit 11 of the sealing device is evacuated by the vacuum exhaust unit 14 (see FIG. 5) so that the degree of vacuum is 10 ⁻⁴ to 10 ⁻² (Pa). ing.

(Cover body joining process)
In the lid bonding step, the temperature in the chamber portion 11 of the sealing device is increased until it reaches the first ultimate temperature T1, and after reaching the first ultimate temperature T1, it is lowered to the second ultimate temperature T2. In this step, nitrogen is injected into the chamber portion 11 of the sealing device at the ultimate temperature T2, and the temperature is further lowered to join the lid 130 to the package 110 via the joining member 131. In the lid joining step, the temperature is increased until it reaches the first attainment temperature T1 shown in the graph of FIG. 4, and after reaching the first attainment temperature T1, the second attainment temperature shown in the graph of FIG. The lid 130 is joined to the package 110 via the joining member 131 by lowering to T2, injecting nitrogen into the chamber portion 11 of the sealing device at the second ultimate temperature T2, and further lowering the temperature. . The graph of FIG. 4 shows the temperature and the degree of vacuum in the chamber portion 11 of the sealing device from before joining to after joining, when joining the lid. The straight line graph shows the progress of the temperature in the chamber portion 11. The one-dot chain line graph shows the progress of the degree of vacuum in the chamber portion 11. The first ultimate temperature T1 described in the graph of FIG. 4 is the melting point of the joining member 131, and is 290 to 330 ° C. when the joining member 131 is made of glass.

As shown in the graph of FIG. 4, the temperature in the chamber portion 11 of the sealing device continues to rise until the first ultimate temperature T1 is reached. Next, after reaching the first ultimate temperature T1, the temperature is lowered to the second ultimate temperature T2, and nitrogen is injected into the chamber portion 11 of the sealing device at the second ultimate temperature T2. The second ultimate temperature T2 described in the graph of FIG. 4 is a softening point of the joining member 131, and is 250 to 290 ° C. when the joining member 131 is made of glass. Further, the inside of the chamber portion 11 of the sealing device is evacuated by the vacuum exhaust portion 14 so that the degree of vacuum is 10 ⁴ to 10 ⁵ (Pa) by injecting nitrogen. ing.

  In this way, the temperature in the chamber portion of the sealing device is raised until it reaches the first ultimate temperature T1, and after reaching the first ultimate temperature T1, it is lowered to the second ultimate temperature T2, and at the second ultimate temperature T2. By injecting nitrogen into the chamber portion of the sealing device, the nitrogen is injected under the temperature condition indicating the softening point of the bonding member 131, so that the bonding member 131 is in a gel state by nitrogen injection. A force that the increased atmospheric pressure presses the lid 130 downward is applied. Therefore, since the force with which the lid body 130 presses the package 110 is increased while suppressing the fluidity of the bonding member 131, the bonding member 131 is suppressed from flowing into the concave portion K and the side surface of the package 110, and is optimal for bonding. Since the thickness of the joining member 131 can be easily controlled, the lid 130 can be stably joined to the package 110. Further, by doing so, the lid body 130 can be joined without attaching a weighting jig, so that cracks and the like of the package 110 can be reduced. In addition, the temperature is raised to the first ultimate temperature T1, which is the melting point of the joining member 131, and the joining member 131 and the lid 130 are firmly joined, and then the second ultimate temperature, which is the softening point of the joining member, from the first attainment temperature T1. The lid 130 can be more stably joined to the package 110 by lowering the temperature to T2 and increasing the pressure in the chamber portion 11 from the second ultimate temperature T2 and simultaneously increasing the viscosity of the joining member 131. it can.

  When the bonding member 131 is made of glass, it can be prevented from flowing out to the side surface of the package 110 by becoming a gel at the softening point that is the second ultimate temperature T2. Moreover, by suppressing the bonding member 131 from flowing out, the bonding strength between the lid 130 and the package 110 can be ensured, and the hermetic sealing property in the recess K can be maintained.

  According to the piezoelectric device manufacturing method of the present invention, the piezoelectric element mounting step of mounting the piezoelectric element 120 on the electrode pad 111 provided on the upper surface of the package 110 via the conductive adhesive 140, and the piezoelectric element 120 are covered. The lid 110 is placed on the package 110 via the bonding member 140, and the package 110 on which the lid 130 is placed on the chamber 11 of the sealing device is accommodated. And the temperature in the chamber portion 11 of the sealing device is raised until reaching the first ultimate temperature T1, and after reaching the first ultimate temperature T1, is lowered to the second ultimate temperature T2. In the state where the second ultimate temperature T2 has been reached, nitrogen is injected into the chamber portion 11 of the sealing device, and the temperature is further lowered, so that the lid body 130 is sealed via the joining member 131. It includes a lid bonding step of bonding the over-di 110. In this way, the temperature in the chamber portion of the sealing device is raised until it reaches the first ultimate temperature T1, and after reaching the first ultimate temperature T1, it is lowered to the second ultimate temperature T2, and at the second ultimate temperature T2. By injecting nitrogen into the chamber portion 11 of the sealing device and injecting nitrogen under a temperature condition indicating the softening point of the joining member 131, the joining member 131 is in a gel state. A pressure is applied to the air pressure raised by the injection to press the lid 130 downward. Therefore, since the force with which the lid body 130 presses the package 110 is increased while suppressing the fluidity of the bonding member 131, the bonding member 131 is suppressed from flowing into the concave portion K and the side surface of the package 110, and is optimal for bonding. Since the thickness of the joining member 131 can be easily controlled, the lid 130 can be stably joined to the package 110. Further, by doing so, the lid body 130 can be joined without attaching a weighting jig, so that cracks and the like of the package 110 can be reduced.

  Further, according to the method for manufacturing a piezoelectric device of the present invention, since the joining member 131 is made of glass, it becomes a gel at the softening point that is the second ultimate temperature T2, and the joining member 131 flows out to the side surface of the package 110. Can be suppressed. By suppressing the bonding member 131 from flowing out, the bonding strength between the lid 130 and the package 110 can be ensured, and the hermetic sealing property in the recess K can be maintained.

  In addition, this invention is not limited to the above-mentioned embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention. For example, in the above-described embodiment, the case where quartz is used as the piezoelectric material constituting the piezoelectric element has been described. However, as other piezoelectric materials, lithium niobate, lithium tantalate, or piezoelectric ceramics is used as the piezoelectric material. A piezoelectric element may be used.

  In the above embodiment, the case where the piezoelectric element 120 uses an AT crystal element has been described. However, a tuning fork type bending having a base and two flat plate-shaped vibrating arms extending in the same direction from the side surface of the base is described. A crystal element may be used. The piezoelectric element includes a crystal piece, an excitation electrode provided on the surface of the crystal piece, an extraction electrode, and a frequency adjusting metal film. The crystal piece includes a crystal base portion and a crystal vibration portion, and the crystal vibration portion includes a first crystal vibration portion and a second crystal vibration portion. The crystal base has an orthogonal coordinate system in which the electrical axis is the X axis, the mechanical axis is the Y axis, and the optical axis is the Z axis as the crystal axis direction, within a range of −5 ° to + 5 ° around the X axis. This is a flat plate having a substantially rectangular shape in a plan view in which the direction of the rotated Z ′ axis is the thickness direction. The first crystal vibrating part and the second crystal vibrating part are extended in parallel with the Y′-axis direction from one side of the crystal base part. Such a crystal piece has a tuning fork shape in which a crystal base and each crystal vibration part are integrated, and is manufactured by a photolithography technique and a chemical etching technique.

DESCRIPTION OF SYMBOLS 110 ... Package 110a ... Board | substrate 110b ... Frame part 111 ... Electrode pad 112 ... External terminal 120 ... Piezoelectric element 121 ... Piezoelectric base plate 122 ... Excitation electrode 123. .... Extraction electrode 130 ... Lid 131 ... Joining member 140 ... Conductive adhesive T1 ... First reached temperature T2 ... Second reached temperature

Claims (2)

A piezoelectric element mounting step of mounting the piezoelectric element on the electrode pad provided on the upper surface of the package via a conductive adhesive;
A lid placing step for placing a lid on the package via a bonding member so as to cover the piezoelectric element;
A vacuum step of accommodating the package on which the lid is placed in a chamber portion of a sealing device, and making the inside of the chamber portion a vacuum atmosphere;
The temperature in the chamber portion of the sealing device is increased until reaching the first ultimate temperature, and after reaching the first ultimate temperature, the temperature is lowered to the second ultimate temperature, and the temperature of the sealing device is reduced to the second ultimate temperature. And a lid joining process for joining the lid to the package through the joining member by injecting nitrogen into the chamber and further lowering the temperature. Method. A method of manufacturing a piezoelectric device according to claim 1,
The method for manufacturing a piezoelectric device according to claim 1, wherein the joining member is made of glass.

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