JP4706546B2 - Method for manufacturing piezoelectric vibration device - Google Patents

Description

The present invention relates to a method for manufacturing a piezoelectric vibration device .

  Currently, examples of the piezoelectric vibration device include a crystal oscillator and a crystal resonator. In this type of piezoelectric vibration device, the main body casing is formed of a rectangular parallelepiped package. This package includes a base and a lid, and at least a piezoelectric vibrating piece such as a quartz vibrating piece is held and bonded to the base by a conductive bonding material. The base and the lid are bonded with a bonding material, whereby the piezoelectric vibrating reed inside the package is hermetically sealed (see, for example, Patent Document 1 below).

In Patent Document 1 described below, a base and a lid are thermally bonded by a bonding material (sealing by brazing or the like in Patent Document 1) using an energy beam such as a laser. In this thermal bonding, the bonding material is heated and melted, and the base and the lid are bonded via the molten bonding material.
JP 2005-191709 A

  By the way, when the bonding material is heated by the energy beam, the temperature of the bonding material can be raised to a desired melting temperature in a short time. As the temperature of the bonding material is raised to a desired melting temperature in a short time, the temperature of the base and the lid also rises rapidly. That is, the thermal gradient of the base and the lid becomes steep. The steep thermal gradient between the base and the lid causes problems of the main body housing such as cracking or distortion of the base or the lid when the base and the lid are joined. In addition, a splash (spark) is generated when the base and the lid are joined, and this splash causes a change or shift in the oscillation frequency of the piezoelectric vibration device.

Accordingly, in order to solve the above-described problems, an object of the present invention is to provide a method for manufacturing a piezoelectric vibration device that suppresses a steep thermal gradient between a lid and a base when the lid and the base are joined.

  In order to achieve the above object, a method of manufacturing a piezoelectric vibration device according to the present invention includes at least a piezoelectric vibration piece hermetically sealed on the base in an internal space of a main body housing formed by joining a lid and a base. In the method of manufacturing a piezoelectric vibrating device, the lid and the base are bonded by thermal bonding using a bonding material, and the bonding is performed while gradually increasing the temperature of the bonding material based on a preset heating condition. It has a thermal joining process which heats material and joins the lid and the base.

  According to the present invention, the bonding between the lid and the base is a thermal bonding using a bonding material, and includes a thermal bonding process. Therefore, by gradually increasing the temperature of the bonding material, the lid and the base are joined. It is possible to suppress a steep thermal gradient of the lid and the base (the main body casing) at the time of joining. For example, the malfunction of the main body casing such that the main body casing is cracked or distorted due to a steep thermal gradient of the main body casing caused by rapid heating of the bonding material when the lid and the base are joined. Can be suppressed. Therefore, as a countermeasure for preventing cracks in the main body casing, it is not necessary to attach a Kovar ring or the like to the joint between the lid and the base, and as a result, Kovar provided in the internal space of the main body casing in order to use the Kovar ring. It is possible to suppress a reduction in the volume of the internal space of the main body housing without requiring a space for holding the ring. In addition, it is possible to suppress the occurrence of splash (spark) at the time of joining the lid and the base, and it is possible to suppress a change or shift in the oscillation frequency of the piezoelectric vibration device due to the splash. It becomes. In addition, the bonding between the lid and the base is a thermal bonding using a bonding material, and includes a thermal bonding step. Therefore, when the bonding of the lid and the base is performed by gradually increasing the temperature of the bonding material. It is possible to suppress a steep thermal gradient of the lid and the base (the main body casing) in the case, and as a result, heat is gently transmitted to the lid and the base, and the coefficient of thermal expansion between the lid and the base is reduced. It is possible to suppress problems due to the difference (deformation of the main body casing, etc.). In addition, when the temperature of the bonding material is suddenly increased by the rapid heating (steep thermal gradient) to the bonding material when the lid and the base are bonded, gas is generated in the internal space of the main body housing. This gas remains in the internal space of the main body housing, and the residual gas increases the internal pressure of the main body housing or contaminates the internal space of the main body housing. However, according to the present invention, the bonding between the lid and the base is a thermal bonding using a bonding material, and includes a thermal bonding process, so that the temperature of the bonding material increases rapidly. There is no such a thing, and it becomes possible to suppress such a malfunction.

  In the method, the thermal bonding step includes an energy beam step of irradiating the lid with an energy beam to heat the bonding material, and a heat plate used for the main body housing with a lower energy than the energy beam. A heat plate step of indirectly heating the material, the temperature increase rate of the bonding material by the heat plate step is lower than the temperature increase rate of the bonding material by the energy beam step, the heat plate step, It may be a process preceding at least the energy beam process.

  In this case, the thermal bonding process includes an energy beam process and a heat plate process, and the temperature increase rate of the bonding material by the heat plate process is lower than the temperature increase rate of the bonding material by the energy beam process, Since the heat plate process is a process preceding at least the energy beam process, the lid and the base (the main body casing) at the time of joining the lid and the base by gradually increasing the temperature of the bonding material. ) Is preferable to moderate the thermal gradient. The thermal bonding process includes an energy beam process and a heat plate process, and a temperature increase rate of the bonding material by the heat plate process is lower than a temperature increase rate of the bonding material by the energy beam process. Since the plate process is a process preceding at least the energy beam process, it is possible to suppress heat dissipation from the portion of the main body housing on the heat plate side when the lid and the base are joined. It becomes possible to increase the joining efficiency between the lid and the base. In addition, among the above-described configurations, the heat plate process is at least a process prior to the energy beam process, and the heat plate process is performed regardless of whether the heat plate process is continued or not. The energy beam process is performed after the heat plate process.

  In the method, the bonding material may be a low melting point material.

  In this case, since the bonding material is a low melting point material, the melting temperature of the bonding material is low, and as a result, it is possible to reduce the thermal gradient of the main body housing at the time of bonding the lid and the base. Become. Therefore, even when the temperature of the bonding material is gradually increased, it is possible to suppress an increase in the bonding time between the lid and the base.

  In the method, a bonding region for bonding to the lid may be formed on the base, and a width of the bonding region may be set to 200 μm or less.

  In this case, a bonding region for bonding to the lid is formed in the base, and the width of the bonding region is set to 200 μm or less, so that the bonding region between the base and the lid in the main body housing is suppressed. This is preferable for reducing the size of the main body casing. In particular, when removing a large number of the bases from a single flat plate, it is necessary to separate (split) the large number of bases from the frame material of the flat plate. In some cases, the width of the base portion related to the bonding region becomes narrower than a predetermined width, resulting in a defect of the base. However, according to the present invention, even in such a case, the base can be used without being defective. Further, in this case, even if the width of the base portion related to the joining region is narrower than in the conventional technique, the base or the lid is cracked when the base and the lid are joined. It is possible to suppress or prevent airtight defects inside the main body casing.

  In the method, the thermal bonding step includes a first thermal bonding step in which a lid and the base are bonded except for a part of the main body housing, and one of the main body housings after the first thermal bonding step. And a second thermal bonding step of bonding the lid and the base with respect to the portion.

  In this case, since the thermal bonding process includes a first thermal bonding process and a second thermal bonding process, the gas generated in the internal space of the main body housing in the first thermal bonding process is converted into the second thermal bonding process. It becomes possible to exhaust to the outside of the main body casing.

  In the method, the heating condition may increase the heating temperature of the bonding material based on a preset temperature increase rate.

  In this case, since the heating condition increases the heating temperature of the bonding material based on a preset temperature increase rate, it is possible to prevent the bonding material from being extended while suppressing an increase in the bonding time between the lid and the base. By gradually increasing the temperature, it is possible to moderate the thermal gradient of the lid and the base (the main body housing) when the lid and the base are joined.

  In the method, the heating condition may be a constant heating temperature of the bonding material.

  In this case, since the heating condition makes the heating temperature of the bonding material constant, by gradually increasing the temperature of the bonding material, the lid and the base (the main body at the time of bonding the lid and the base) This is suitable for gradual thermal gradient of the casing.

  In the method, the heating condition sets a constant interval for the heating time of the bonding material, makes the heating temperature of the bonding material constant in the interval, and the heating temperature of the bonding material between the intervals. May be raised based on a preset temperature rise rate.

  In this case, the heating condition sets a fixed interval for the heating time of the bonding material, makes the heating temperature of the bonding material constant in the interval, and sets the heating temperature of the bonding material between the intervals. Since the temperature is increased based on a preset temperature increase rate, the thermal gradient of the lid and the base (the main body housing) at the time of joining the lid and the base is increased by gradually increasing the temperature of the joining material. It is suitable for making it gentle.

According to the method for manufacturing a piezoelectric vibrating device according to the present invention, it is possible to suppress a steep thermal gradient between the lid and the base when the lid and the base are joined.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, a case where the present invention is applied to a crystal resonator as a piezoelectric vibration device is shown.

  In the crystal resonator 1 according to the present embodiment, as shown in FIG. 1, a tuning fork type crystal vibrating piece 2 (piezoelectric vibrating piece in the present invention), a base 3 holding the crystal vibrating piece 2, and a base 3 And a lid 4 for hermetically sealing the held crystal vibrating piece 2.

  In this crystal unit 1, a main body housing 5 is composed of a base 3 and a lid 4. The base 3 and the lid 4 are thermally bonded via a bonding material 61 to form an internal space of the main body casing 5, and the crystal resonator element conductive bonding is formed on the base 3 in the internal space of the main body casing 5. The quartz crystal vibrating piece 2 is held and bonded via a material 62 (hereinafter also referred to as a conductive bonding material for the vibrating piece), and the internal space of the main body housing 5 is hermetically sealed. At this time, as shown in FIG. 1, the base 3 and the crystal vibrating piece 2 are ultrasonically bonded and electromechanically bonded by the FCB (Flip Chip Bonding) method using the conductive bonding material 62 for the vibrating piece. ing. The resonator element conductive bonding material 62 used in the present embodiment is a connection bump made of a metal material such as gold. In this embodiment, a low melting point material made of gold (or silver) and tin is used for the bonding material 61. Next, each configuration of the crystal resonator 1 will be described.

  As shown in FIG. 1, the crystal vibrating piece 2 is a tuning fork type crystal vibrating piece, and is formed by etching from a crystal piece made of anisotropic material. The substrate 21 of the quartz crystal vibrating piece 2 is composed of two leg portions 22 and a base portion 23, and the outer peripheral shape thereof is a substantially rectangular parallelepiped shape, and the two leg portions 22 are formed so as to protrude from the base portion 23. In addition, grooves 25 are formed in both main surfaces 24 of the two leg portions 22 in order to improve the series resonance resistance value that deteriorates due to the miniaturization of the crystal vibrating piece 2. On both main surfaces 24 of the quartz crystal vibrating piece 2, two excitation electrodes 26 configured with different potentials, and lead electrodes 27 for electromechanically joining these excitation electrodes 26 to the electrode pads 34 of the base 3. And the extraction electrode 27 is extracted from the excitation electrode 26 to the base 23. Then, the lead electrode 27 formed on the base 23 and the electrode pad 34 of the base 3 are joined by the conductive member 62 for the resonator element, and the excitation electrode 26 and the electrode pad 34 are electromechanically joined. The excitation electrode 26 and the extraction electrode 27 of the quartz crystal resonator element 2 are, for example, a laminated thin film composed of a chromium base electrode layer and a gold upper electrode layer. This thin film is formed on the entire surface by a technique such as vacuum deposition or sputtering, and then formed into a desired shape by metal etching by photolithography.

  As shown in FIG. 1, the base 3 is formed in a box-like body composed of a bottom portion 31 and a bank portion 32 extending upward from the bottom portion 31. The base 3 is formed by laminating a rectangular parallelepiped of a ceramic material on a single plate having a rectangular shape in a plan view made of a ceramic material, and integrally firing in a concave shape. Moreover, the bank part 32 is shape | molded along the surface outer periphery of the bottom part 31 shown to Fig.1 (a). The upper surface of the bank portion 32 is a bonding area with the lid 4, and the width of the bonding area is set to 200 μm or less. In this bonding region, a metallized layer 33 (for example, a structure in which nickel and gold are plated in this order on the tungsten metallized layer) for bonding to the lid 4 is provided. The base 3 is formed with a plurality of electrode pads 34 that are electromechanically bonded to the excitation electrodes 26 of the crystal vibrating piece 2. These electrode pads 34 are each electromechanically bonded to terminal electrodes 35 formed on the outer peripheral back surface of the base 3. These terminal electrodes 35 are connected to external parts and external devices. The electrode pads 34 and the terminal electrodes 35 are formed by printing integrally with the base 3 after printing a metallized material such as tungsten or molybdenum. Some of these electrode pads 34 and terminal electrodes 35 are formed by forming nickel plating on the upper portion of the metallization and forming gold plating on the upper portion thereof.

  The lid 4 is made of a metal material, and is formed into a single plate having a rectangular shape in plan view, as shown in FIG. A bonding material 61 is formed on the lower surface of the lid 4. The lid 4 is mechanically joined to the base 3 via a joining material 61 by a technique such as seam welding or beam welding, so that the body housing 5 of the crystal unit 1 is constituted by the lid 4 and the base 3. . The lid 4 is made of, for example, four layers of metal materials having different thermal expansion coefficients. Specifically, the bonding material 61, the nickel layer, the kovar layer, and the nickel layer are sequentially laminated from the lower surface of the lid 4 that serves as a bonding surface with the base 3. In this embodiment, the bonding material 61 is formed into an annular layer along the outer peripheral edge of the lower surface of the lid 4 and is made of tin and gold (the ratio of tin and gold is about 2 to 8) or tin and silver. Consists of layers.

  In the crystal resonator 1 described above, the crystal vibrating piece 2 is ultrasonically bonded to the base 3 by the FCB method using the conductive bonding material 62 for the vibrating piece, and after the crystal vibrating piece 2 is bonded to the base 3, the base 3 And the lid 4 are thermally bonded using the bonding material 61, and the crystal vibrating piece 2 is hermetically sealed on the base 3 in the internal space of the main body housing 5 formed by thermal bonding of the lid 4 and the base 3. Manufactured. In addition, the heat joining of the base 3 and the lid | cover 4 here is performed by the process shown below.

  The heat bonding between the base 3 and the lid 4 is performed by an in-line type bonding apparatus 8 (see FIG. 2) that simultaneously bonds the plurality of bases 3 and the lid 4 using a pallet 81 (FIG. 2).

  As shown in FIG. 2, the in-line type joining device 8 raises the temperature of the base 3 and the lid 4 arranged on the pallet 81, and the transport outlet 82 for transporting and unloading the pallet 81 to and from the joining device 8. A heat plate 83, a heat insulating portion 84 that insulates the heat of the heat plate 83 so as not to be transmitted to a movable portion (mechanism / drive portion not shown) of the apparatus 8, and a lid placement portion 85 that places the lid 4 on the base 3. And a laser part 86 for thermally joining the base 3 and the lid 4 with a laser. As shown in FIG. 2, a heat plate 83 is disposed below the conveyance exit path 82, a heat insulating portion 84 is disposed below the heat plate 83, and a movable portion (mechanism / drive portion) (not shown) is disposed below the heat insulating portion 84. It is arranged. In addition, a lid placement portion 85 and a laser portion 86 are arranged above the conveyance exit path 82. In the joining apparatus 8 shown in FIG. 2, the pallet 81 is transported on the transport exit path 82 along the arrow direction.

  The conveyance exit path 82 may be a pickup type conveyance exit path that picks up the pallet 81 and conveys the pallet 81 to the lid placement portion 85 and the laser portion 86, and the pallet 81 is sequentially flowed (moved) to the lid placement portion 85. Alternatively, the conveyor path 82 may be a belt conveyor type that conveys the laser part 86.

  In the heat plate 83, the heating temperature can be arbitrarily set and changed depending on the thermal bonding environment and the number of simultaneous bondings of the base 3 and the lid 4. In the present embodiment, since the melting temperature of the bonding material 61 is 280 ° C., the heating temperature of the heat plate 83 is set so that the temperature of the bonding material 61 is increased by 50 ° C. by the heat plate 83.

  The heat insulating part 84 insulates the movable part (mechanism / drive part) using a fluid such as gas (inert gas or the like) or liquid (water).

  In the laser unit 86, laser scanning, laser output, laser scanning method, and the like when performing thermal bonding between the base 3 and the lid 4 are set based on preset heating conditions.

  In the thermal bonding of the base 3 and the lid 4 using the above-described inline type bonding apparatus 8, first, the base 3 provided with 20 bonding materials 61 on one pallet 81 is formed in a matrix (in this embodiment, 2). × 10). 2 shows a state in which the base 3 is arranged only in the leftmost pallet 81 in the figure, and the state in which the base 3 is arranged in other pallets 81 is omitted.

  The pallet 81 on which the base 3 is arranged is transported to the transport exit path 82. At this time, the base 3 and the bonding material 61 are heated by the heat plate 83 while gradually increasing the temperature of the bonding material 61 based on a preset heating condition. The bonding material 61 is indirectly heated by the heat plate 83 (heat plate process referred to in the present invention). The heating condition of the heat plate process is set so that the temperature of the bonding material 61 increases by 50 ° C. when the base 3 and the lid 4 are bonded by the laser unit 86. Moreover, the heat energy by the heat plate 83 is set to be constant, and thereby the heating temperature of the bonding material 61 is constant.

  The pallet 81 is conveyed while the base 3 and the bonding material 61 are heated by the heat plate 83, and the lid 4 is arranged on the 20 bases 3 on the pallet 81 by the lid placement unit 85. During this process, the lid 4 is heated by the heat plate 83.

  After the lid 4 is disposed on the base 3, the lid 4 is thermally bonded to the bonding region (metallized layer 33) of the base 3 in the laser unit 86 (energy beam process referred to in the present invention). Here, as shown in FIG. 3, the bonding material 61 on the upper surface of the bank portion 32 is rotated clockwise (in the direction of the arrow) from one corner (the lower left corner of the base 3 in the drawing) of the bonding region (metallized layer 33) of the base 3. The base 3 and the lid 4 are melted by laser, and thermal bonding between the base 3 and the lid 4 is performed based on preset heating conditions. Specifically, in the thermal bonding of the bonding region (metallized layer 33) of the base 3 by the laser according to the present embodiment, the upper surface (periphery in plan view) of the bank portion 32 of the base 3 is turned around a plurality of times in the clockwise direction (arrow direction). Thermal joining of the base 3 and the lid 4 is performed. The heating condition of the energy beam process is set so that the temperature of the bonding material 61 is increased by 280 ° C. when the base 3 and the lid 4 are bonded by the laser unit 86. Further, the heat energy by the laser is set to be constant, and thereby the heating temperature of the bonding material 61 becomes constant. Further, in this energy beam process, the base 3 and the lid 4 are thermally bonded by energy higher than the heat energy by the heat plate 83 described above. That is, the temperature increase rate of the bonding material 61 by the heat plate process is set lower than the temperature increase rate of the bonding material 61 by the energy beam process.

  As described above, the base 3 and the lid 4 are thermally bonded by the heat plate process and the energy beam process to constitute the main body casing 5. After that, the main body housing 5 is unloaded from the conveyance exit path 82, and the thermal bonding process (the heat plate process and the energy beam process described above) between the base 3 and the lid 4 in the bonding apparatus 8 is completed. Note that the heating conditions of the main heat bonding process are as described above, in which the heating temperature of the bonding material 61 in the heat plate process and the energy beam process is made constant, and the temperature increase rate of the bonding material 61 in the heat plate process is the energy beam. It is to set lower than the temperature increase rate of the bonding material 61 by the process. In other words, the heating conditions are classified into the heating time of the bonding material 61 as the single heating time of the heat plate process alone and the combined heating time consisting of the heat plate process and the energy beam process (setting of intervals in the present invention). The heating temperature of the bonding material 61 in the single heating time and the combined heating time is made constant, and the heating temperature of the bonding material 61 is set based on a preset temperature increase rate when shifting from the single heating time to the combined heating time. It is to raise.

  According to the above-described embodiment, since the bonding between the lid 4 and the base 3 is thermal bonding using the bonding material 61 and includes a thermal bonding process, the lid 4 can be obtained by gradually increasing the temperature of the bonding material 61. A steep thermal gradient between the lid 4 and the base 3 (main body housing 5) at the time of joining to the base 3 can be suppressed. For example, the malfunction of the main body housing 5 such as the main body housing 5 being cracked or distorted due to the steep thermal gradient of the main body housing 5 caused by the rapid heating of the bonding material 61 when the lid 4 and the base 3 are joined. Can be suppressed. Therefore, it is not necessary to attach a Kovar ring or the like to the joint between the lid 4 and the base 3 as a measure for preventing cracks in the main body casing 5, and as a result, Kovar provided in the internal space of the main body casing 5 to use the Kovar ring. A space for holding the ring is not required, and the volume of the internal space of the main body housing 5 can be suppressed from being reduced. In addition, it is possible to suppress the occurrence of splash (spark) when the lid 4 and the base 3 are joined, and it is possible to suppress a change or shift in the oscillation frequency of the crystal resonator 1 due to the splash. it can.

  In addition, since the bonding between the lid 4 and the base 3 is thermal bonding using the bonding material 61 and includes a thermal bonding process, the temperature of the bonding material 61 is gradually increased so that the lid 4 and the base 3 can be bonded. The steep thermal gradient of the lid 4 and the base 3 (main body housing 5) can be suppressed, and as a result, heat is gently transmitted to the lid 4 and the base 3, and the difference in thermal expansion coefficient between the lid 4 and the base 3 is reduced. Inconvenience (deformation of the main body housing 5 and the like) due to can be suppressed.

  Further, when the temperature of the bonding material 61 is rapidly increased by the rapid heating (steep thermal gradient) to the bonding material 61 when the lid 4 and the base 3 are bonded, gas is generated in the internal space of the main body housing 5. This gas remains in the internal space of the main body housing 5, and the internal pressure of the main body housing 5 increases due to the remaining gas or the internal space of the main body housing 5 is contaminated. However, according to the present embodiment, the bonding of the lid 4 and the base 3 is a thermal bonding using the bonding material 61 and includes a thermal bonding process, so that the temperature of the bonding material 61 rapidly increases. Such a problem can be suppressed.

  Further, the thermal bonding process includes an energy beam process and a heat plate process. The temperature increase rate of the bonding material 61 by the heat plate process is lower than the temperature increase rate of the bonding material 61 by the energy beam process. Since it is a process at least before the energy beam process, the thermal gradient of the lid 4 and the base 3 (main body casing 5) during the joining of the lid 4 and the base 3 is moderated by gradually increasing the temperature of the bonding material 61. Is preferable.

  Further, the thermal bonding process includes an energy beam process and a heat plate process. The temperature increase rate of the bonding material 61 by the heat plate process is lower than the temperature increase rate of the bonding material 61 by the energy beam process. Since it is at least a process prior to the energy beam process, it is possible to suppress heat radiation from the body housing 5 portion on the heat plate 83 side when the lid 4 and the base 3 are joined. Bonding efficiency can be increased. Of the processes of the above-described embodiments, the heat plate process is at least a process prior to the energy beam process, and the energy beam is performed regardless of whether the heat plate process is performed or not. The process is performed after the heat plate process.

  Further, since the bonding material 61 is a low-melting-point material, it is possible to suppress an increase in the bonding time between the lid 4 and the base 3 even when the temperature of the bonding material 61 is gradually increased.

  In addition, since a joining area for joining the lid 4 is formed in the base 3 and the width of the joining area is set to 200 μm or less, the joining area between the base 3 and the lid 4 in the main body housing 5 is suppressed, and This is preferable for reducing the size of the main body housing 5. The aspect ratio between the width and height of the bank portion 32 of the base 3 preferably has a relationship of height> width.

  Further, since the heating condition increases the heating temperature of the bonding material 61 based on the temperature increase rate set in advance as described above, the bonding material is suppressed while preventing the bonding time between the lid 4 and the base 3 from being extended. By gradually increasing the temperature of 61, the thermal gradient of the lid 4 and the base 3 (main body housing 5) when the lid 4 and the base 3 are joined can be moderated.

  Further, since the bonding material 61 is formed into an annular layer along the outer peripheral edge of the lower surface of the lid 4, the amount of the bonding material 61 disposed in the main body housing 5 (internal space) can be suppressed. As a result, generation of gas can be suppressed. In particular, it is preferable when gold and tin are used as the material of the bonding material 61.

  In this embodiment, the bonding material 61 made of gold (silver) and tin is used. However, the bonding material 61 is not limited to this, and may be a low melting point material such as copper or tin alone or lead-free solder. Moreover, other metal materials, such as a silver solder (a lid | cover material is required when using a silver solder), may be sufficient. For example, when a copper layer is used as the bonding material 61 on the lower surface side (bonding surface with the base 3) of the lid 4, thermal bonding with the base 3 made of ceramic is easier than other layers. Further, since the Kovar layer is laminated on this copper layer, the thermal expansion coefficient of the base 3 and the lid 4 can be made equal by making the thermal expansion coefficient of the ceramic base 3 substantially the same.

  In this embodiment, the material of the lid 4 described above is used. However, the present invention is not limited to this, and according to this embodiment, the thermal gradient of the lid 4 itself can be suppressed. It is also possible to comprise a Kovar layer and a nickel layer.

  Further, in this embodiment, the base 3 and the lid 4 are thermally bonded by the laser by the laser unit 86. However, this is a preferred example, and is not limited to this. What is necessary is just thermal joining with the lid | cover 4, and you may perform thermal joining with the base 3 and the lid | cover 4 by an electron beam.

  In this embodiment, the quartz crystal resonator element 2 is hermetically sealed on the base 3 in the internal space of the main body housing 5, but the members provided on the base 3 in the internal space of the main body housing 5 are The crystal vibrating piece 2 is not limited to a single unit, and an electronic component such as an integrated circuit element or another crystal vibrating piece may be provided.

  Further, in this embodiment, as shown in FIG. 1, a lid 4 formed in a rectangular parallelepiped on a rectangular plate in plan view and a base 3 formed in a concave shape are used, but the present invention is not limited to this. It is not something. If the crystal vibrating piece 2 can be hermetically sealed by the base 3 and the lid 4, the shapes of the base and the lid may be arbitrarily set. That is, the joining region of the base 3 is not limited to the bank portion 32 formed along the outer periphery of the surface of the bottom portion 31, and the lid 4 and the base 3 are thermally joined, and the internal space of the main body housing 5 is formed. As long as it is possible to form and hermetically seal the internal space, it may be designed arbitrarily.

  In this embodiment, the tuning fork type crystal vibrating piece is used as the crystal vibrating piece 2. However, the present invention is not limited to this, and a thickness-shear vibration type crystal vibrating piece may be used. For example, as shown in FIG. The crystal vibrating piece 7 may be used. As shown in FIG. 4, the quartz crystal vibrating piece 7 includes an AT-cut quartz piece substrate 71 and is formed into a rectangular parallelepiped having a rectangular shape in plan view. That is, the outer peripheral shape of the substrate 71 is a rectangular parallelepiped shape. In order to cope with the high frequency of the crystal vibrating piece 7, the main surface 72 of the substrate 71 is formed with a recess 75 by a technique such as etching, and a part of the crystal vibrating piece 7 is formed thin. Yes. Excitation electrodes 73 are formed on both main surfaces 72 of the thin quartz resonator element 7 (inner bottom surfaces of the recesses 75), and these excitation electrodes 73 are connected to external electrodes (this embodiment) by the conductive adhesive 62 for the resonator element. Then, an extraction electrode 74 extracted from the excitation electrode 73 is formed for electromechanical bonding with the electrode pad 34) of the base 3. The excitation electrode 73 and the extraction electrode 74 are formed by photolithography, for example, in the order of chromium and gold (Cr—Au) from the substrate 71 side, or chromium, gold, and chromium (Cr—Au—Cr). Or in order of chromium, gold, nickel (Cr—Au—Ni), or in order of chromium, silver, chromium (Cr—Ag—Cr), or in order of chromium, nickel (Cr—Ni), or nickel, It is formed by stacking chromium (Ni—Cr) in this order.

  In the present embodiment, the quartz crystal vibrating piece 2 is directly joined to the base 3 by the vibrating piece conductive bonding material 62, but the present invention is not limited to this, and the quartz crystal vibrating piece 2 is connected via another member. May be indirectly joined to the base 3. For example, the crystal vibrating piece 2 may be joined to the base 3 via a support material in order to reduce external stress on the crystal vibrating piece 2.

  In the crystal resonator 1 according to the above-described embodiment, only the connection bump made of a metal material such as gold is used as the vibration piece conductive bonding material 62, but the connection piece made of another metal material is used. Also good. Moreover, you may use the conductive resin adhesive which consists of not only a connection bump but a silicone resin.

  In this embodiment, a tungsten metallized layer is used as the material of the metallized layer 33 of the base 3, but the present invention is not limited to this, and a molybdenum metallized layer may be used, which consists of tungsten and molybdenum. A metallized layer may be used.

  In the present embodiment, the metallized layer 33 of the base 3 and the bonding material 61 are distinguished from each other, but the structure is not limited thereto. The metallized layer 33 is included in a part of the bonding material 61. It is good also as a structure.

  In the present embodiment, the bonding material 61 is formed on the lower surface of the lid 4, but the present invention is not limited to this. For example, the bonding material 61 may be formed on the metallized layer 33 of the base 3 and the base 3 and the lid 4 may be thermally bonded. In this case, the uppermost surface of the metallized layer 33 of the base 3 is a gold plating layer. It is preferable. Further, the bonding material 61 may be disposed at the time of thermal bonding between the base 3 and the lid 4 without being formed in advance on the lower surface of the lid 4 or the metallized layer 33 of the base 3.

  In this embodiment, the bonding material 61 is composed of tin and gold, or tin and silver. However, the present invention is not limited to this, and other combinations may be used as long as they are alloys.

  In the present embodiment, the bonding material 61 is formed in an annular layer along the outer peripheral edge of the lower surface of the lid 4. However, the present invention is not limited to this, and the bonding material 61 is formed on the entire lower surface of the lid 4. May be.

  Further, in the present embodiment, the lid placement portion 85 and the laser portion 86 are arranged in parallel above the transport exit path 82, but the present invention is not limited to this, and the lid is disposed at the same position above the transport exit path 82. The part 85 and the laser part 86 may be arranged.

  In this embodiment, the heat plate process is performed first, and the energy beam process is performed while performing the heat plate process. However, the present invention is not limited to this, and the heat plate process is at least more than the energy beam process. It may be a pre-process, and the heat plate process may be performed, and the energy beam process may be performed after the heat plate process.

  Further, in the energy beam process of the present embodiment, the base 3 and the lid 4 are thermally bonded by the laser by turning around the upper surface (outer periphery in plan view) of the base 3 in a plurality of clockwise directions. Is a preferred example and is not limited to this. The base 3 and the lid 4 are thermally bonded by laser by turning the upper surface (outer periphery in plan view) of the base 3 clockwise one turn. Also good.

  Further, in the energy beam process of the present embodiment, the base 3 and the lid 4 are thermally bonded by the laser by turning the upper surface (outer periphery in plan view) of the base 3 in the clockwise direction. Instead, the base 3 and the lid 4 may be thermally bonded by laser while turning the upper surface (outer periphery in plan view) of the bank portion 32 of the base 3 counterclockwise.

  Further, in the energy beam process of the present embodiment, the base 3 and the lid 4 are thermally bonded by the laser by turning around the upper surface (outer periphery in plan view) of the base 3 in a plurality of clockwise directions. It is not limited to this, The order of the side which performs thermal joining among the upper surfaces (planar view outer periphery) of the bank part 32 of the base 3 is set, and the thermal joining of the base 3 and the lid 4 is performed based on the set order. You may go. Specifically, taking the base 3 shown in FIG. 3 as an example, thermal bonding with the lid 4 is performed twice on the opposite side along the longitudinal direction of the upper surface of the bank portion 32, and then facing along the short direction. You may heat-join the lid | cover 4 about the edge | side once.

  Further, in the energy beam process of the present embodiment, the base 3 and the lid 4 are thermally bonded by the laser by turning the upper surface (outer periphery in plan view) of the base 3 in the clockwise direction. However, the base 3 and the lid 4 may be temporarily fixed and joined. In this case, when the base 3 and the lid 4 are joined, it is possible to improve the joining accuracy by suppressing the lid 4 from being lifted with respect to the base 3. As a result, uniform heat can be applied to the entire upper surface (outer periphery in plan view) of the bank portion 32 of the base 3.

  Further, in the energy beam process of the present embodiment, the base 3 and the lid 4 are thermally bonded by the laser by turning around the upper surface (outer periphery in plan view) of the base 3 in a plurality of clockwise directions. Is a preferred example and is not limited thereto. For example, the energy beam process removes a part of the main body housing 5 and joins the lid 4 and the base 3, and the lid 4 covers a part of the main body housing 5 after the first thermal joining step. And a second thermal bonding step for bonding the base 3 to the base 3. A specific example is shown in FIG. As shown in FIG. 5, the upper surface (outer periphery in plan view) of the bank portion 32 of the base 3 is slightly turned clockwise in the direction of the solid arrow in the clockwise direction, and the base 3 and the lid 4 are thermally bonded by laser (first heat). Joining process). After the first thermal bonding step, the gas generated in the internal space of the main body housing 5 is exhausted, and after the gas is exhausted, the base 3 and the lid 4 are not thermally bonded by laser (metallized region). The layer 33) is thermally bonded by laser between the base 3 and the lid 4 in the direction of the broken line arrow. In this case, since the thermal bonding process (in this specific example, the energy beam process) includes the first thermal bonding process and the second thermal bonding process, the gas generated in the internal space of the main body housing 5 in the first thermal bonding process is reduced. In the second heat bonding step, the air can be exhausted to the outside of the main body housing 5. In this specific example, a heat bonding process is employed in which the upper surface (outer periphery in plan view) of the base 3 of the base 3 described above is turned clockwise once and the base 3 and the lid 4 are thermally bonded by laser. Needless to say, the present invention is not limited to this.

  Further, in this embodiment, the heating temperature of the bonding material 61 in the heat plate process and the energy beam process is made constant, and the temperature increase rate of the bonding material 61 in the heat plate process is higher than the temperature increase rate of the bonding material 61 in the energy beam process. However, this is a preferable example for shortening the manufacturing time, and the present invention is not limited to this. For example, the heating temperature of the bonding material 61 in the heat plate process and the energy beam process may be made constant, and the temperature increase rate of the bonding material 61 in the heat plate process and the energy beam process may be set constant. Even in this case, as in the above-described embodiment, the temperature of the lid 4 and the base 3 (main body casing 5) is increased when the lid 4 and the base 3 are joined by gradually increasing the temperature of the joining material 61. It is suitable for making the gradient gentle.

  In this embodiment, the heating time of the bonding material 61 is classified into a single heating time for the heat plate process alone and a combined heating time for the heat plate process and the energy beam process. The heating temperature of the bonding material 61 is made constant, and the heating temperature of the bonding material 61 in each single heating time and combined heating time is increased based on a preset temperature increase rate. However, the present invention is not limited to this. A fixed interval is set for the heating time of the bonding material 61, the heating temperature of the bonding material 61 in the interval is made constant, and the heating temperature of the bonding material 61 is set in advance between the intervals. What is necessary is just to raise based on the set temperature rise rate. For example, in the above-described embodiment, in the energy beam process, the base 3 and the lid 4 are thermally bonded by the laser by turning around the upper surface (outer periphery in plan view) of the base 3 in a plurality of clockwise directions. The fixed interval is set to a time (which may be a step) in which the base 3 and the lid 4 are thermally bonded by the laser around the circumference of the base 3 in a plan view in the clockwise direction. The heating temperature may be increased by a certain amount. Even in this case, as in the above-described embodiment, the temperature of the lid 4 and the base 3 (main body casing 5) is increased when the lid 4 and the base 3 are joined by gradually increasing the temperature of the joining material 61. It is suitable for making the gradient gentle.

  It should be noted that the present invention can be implemented in various other forms without departing from the spirit, gist, or main features. For this reason, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

The present invention can be applied to a method for manufacturing a piezoelectric vibration device such as a crystal resonator or a crystal oscillator.

FIG. 1 is a schematic configuration diagram of a crystal resonator according to the present embodiment. FIG. 1A is a schematic plan view showing the inside of the crystal resonator. FIG.1 (b) is the sectional view on the AA line of Fig.1 (a). FIG. 2 is a schematic configuration perspective view of the in-line type joining apparatus according to the present embodiment. FIG. 3 is a schematic plan view of the base showing the thermal bonding process between the base and the lid by the laser part in the manufacturing method (thermal bonding process) of the crystal resonator according to this example. FIG. 4 is a schematic configuration diagram of a quartz crystal resonator element according to another example of the present embodiment. FIG. 4A is a schematic plan view showing the inside of the crystal resonator. FIG. 4B is a cross-sectional view taken along line A′-A ′ of FIG. FIG. 5 is a schematic plan view of a base showing a thermal bonding process between a base and a lid by a laser part in a method for manufacturing a crystal resonator (thermal bonding process) according to another example of the present embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crystal resonator 2 Tuning fork type crystal vibrating piece 3 Base 33 Metallized layer 4 Lid 5 Body housing 61 Bonding material 7 Crystal vibrating piece 83 Heat plate 86 Laser part

Claims (8)

In the method of manufacturing a piezoelectric vibration device in which at least a piezoelectric vibrating piece is hermetically sealed on the base in the internal space of the main body casing formed by joining the lid and the base,
Bonding the lid and the base is thermal bonding using a bonding material,
A piezoelectric vibration device comprising: a thermal bonding step of bonding the lid and the base by heating the bonding material while gradually raising the temperature of the bonding material based on a preset heating condition Production method. The thermal bonding process includes an energy beam process in which the lid is irradiated with an energy beam to heat the bonding material, and the bonding material is indirectly applied with energy lower than the energy beam using a heat plate in the main body housing. And a heat plate process for heating to
The temperature increase rate of the bonding material by the heat plate process is lower than the temperature increase rate of the bonding material by the energy beam process,
The method of manufacturing a piezoelectric vibration device according to claim 1, wherein the heat plate process is a process preceding at least the energy beam process.   The method for manufacturing a piezoelectric vibration device according to claim 1, wherein the bonding material is a low melting point material.   The piezoelectric vibration device according to claim 1, wherein a bonding region for bonding to the lid is formed on the base, and a width of the bonding region is set to 200 μm or less. Manufacturing method.   The thermal bonding step includes a first thermal bonding step in which a lid and the base are bonded except for a part of the main body housing, and a lid on a part of the main body housing after the first thermal bonding step. 5. The method of manufacturing a piezoelectric vibration device according to claim 1, further comprising a second thermal bonding step of performing bonding with the base.   The method for manufacturing a piezoelectric vibration device according to claim 1, wherein the heating condition is to raise the heating temperature of the bonding material based on a preset temperature increase rate.   6. The method of manufacturing a piezoelectric vibration device according to claim 1, wherein the heating condition is such that a heating temperature of the bonding material is constant.   The heating conditions set a certain interval for the heating time of the bonding material, set the heating temperature of the bonding material within the interval constant, and preset the heating temperature of the bonding material between the intervals. The method of manufacturing a piezoelectric vibration device according to claim 1, wherein the temperature is increased based on a rate of temperature increase.

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