JP4704819B2 - Method for manufacturing piezoelectric device - Google Patents

Description

  The present invention relates to a piezoelectric device such as a piezoelectric vibrator or a piezoelectric oscillator used in an electronic device such as a portable communication device or an electronic computer.

  Conventionally, a piezoelectric vibration element in which electrodes are formed on both main surfaces of a piezoelectric element plate is mounted inside a package, for example, a piezoelectric vibrator, a piezoelectric oscillator in which a piezoelectric vibrator and an oscillation circuit are mounted in the same package, or Piezoelectric devices such as a piezoelectric filter that separates a specific frequency band are often used in electronic devices such as portable communication devices and electronic computers. In recent years, piezoelectric devices having a shape corresponding to surface mounting have been developed, and with the miniaturization of electronic equipment, these piezoelectric devices are also being miniaturized.

As an example of such a conventional piezoelectric device, FIG. 6 shows a crystal resonator using quartz as a piezoelectric material. A pair of element connection electrode pads are provided on the bottom surface of the recessed space formed in the container body 21. On this element connection electrode pad, there is mounted a crystal resonator element 22 having a pair of excitation electrodes electrically connected via a conductive adhesive on the front and back main surfaces. A sealing material 23 is attached to the top of the side wall of the surrounding container body 21. A metal lid 24 is placed on the sealing material 23, and the sealing material 23 and the lid 24 are joined by heat welding or the like, whereby the mounting space (recessed space) of the crystal resonator element 22 is hermetically sealed. It is a stopped crystal unit. (For example, see Patent Document 1 below.)

  In such a crystal resonator, when an externally varying voltage is applied between the excitation electrodes of the crystal resonator element 22 via an input / output terminal provided on the lower surface of the container body 21 and an external terminal 25 such as a ground terminal. In addition, vibration is generated in a predetermined vibration mode according to the characteristics of the crystal resonator element 22, and a reference signal having a predetermined frequency is oscillated and output by an external oscillation circuit based on the resonance frequency. Such a reference signal is used as a clock signal in an electronic device such as a portable communication device.

The following documents are disclosed about the piezoelectric device including the above-described crystal resonator and the like.
JP-A-9-116365

  In addition, the applicant did not come to discover prior art documents related to the present invention by the time of the filing of the application other than the prior art documents specified by the prior art document information described above.

  However, according to the conventional piezoelectric device, since it is necessary to form one sealing layer for each piezoelectric device on the top of the side wall that surrounds the recessed space, there is a drawback that productivity is lowered.

  According to the present invention, a sealing material is collectively formed on each device in a state of a master substrate in which a plurality of device formation regions each having a recessed space for mounting the piezoelectric vibration element as described above are connected in a matrix. An object of the present invention is to provide a method of manufacturing a piezoelectric device that can improve productivity.

The method for manufacturing a piezoelectric device of the present invention is a method for manufacturing a piezoelectric device in which at least a piezoelectric vibration element is mounted in a recessed space formed on a substrate, and the recessed space is hermetically sealed by a lid disposed on an opening of the recessed space. in the method, the rectangular device formation region front main surface of the inner is provided with concave space formed by being surrounded by the enclosure, on the outside of the enclosure is provided with a groove, the groove The outer circumference of the device coincides with the outer circumference of the device forming area, and a marginal area is provided in the outer circumference of each device forming area, and an inlet port connected to the groove portion is provided in the marginal area. a step a of forming a master substrate which is configured integrally by arranging the device forming region and捨代region into a plurality matrix consists brazing material gold-tin or gold-germanium into the groove from the inlet portion Seal Step B of forming a sealing material layer filling the timber, mounting the piezoelectric vibrating element in the space portion, then, on top of the sealing material layer, the corresponding lid of each device forming region and捨代region a step C but which place the master lid that is configured integrally by arranging a plurality matrix to seal the space of each hermetically joined to the sealing material layer and the master lid, master And a step D of cutting a portion where the substrate, the sealing material layer, and the master lid body are overlapped to obtain a plurality of piezoelectric devices at the same time.

  According to the method for manufacturing a piezoelectric device of the present invention, the outer periphery of the surrounding portion surrounding the space portion is provided with a groove portion for forming a sealing material, and the device forming region in which the groove portion or the like is formed is provided. By forming a master substrate that is arranged in a matrix and integrally formed in a matrix, and forming a sealing material layer in each groove, the sealing material is collectively applied to each device forming region in the state of the master substrate. Therefore, productivity as a piezoelectric device can be improved.

  Further, according to the method for manufacturing a piezoelectric device of the present invention, a marginal area is provided on the outer periphery of the device formation area, and a sealing material that becomes a sealing material layer formed in the groove portion is provided in the marginal area. By providing the injection port for injection, the exclusive area for each component in the device formation region can be used effectively.

  Furthermore, according to the method for manufacturing a piezoelectric device of the present invention, when the sealing portion is applied to the injection port portion by connecting the injection port portion and the groove portions of the plurality of device formation regions, the groove portion of each device formation region is connected. The encapsulant flows into the device, and the encapsulant layer in each device formation region can be formed collectively.

  Furthermore, according to the method for manufacturing a piezoelectric device of the present invention, since the sealing material is formed of the brazing material, it is possible to improve the impact resistance characteristics as the piezoelectric device.

  FIG. 1 is an exploded perspective view illustrating a crystal resonator as one of piezoelectric devices in a piezoelectric device manufactured by the manufacturing method of the present invention, and FIG. 2 is an assembly of the crystal resonator disclosed in FIG. It is sectional drawing which showed the form after a short time. 1 and 2 generally includes a container body 1, a crystal vibration element 2 as a piezoelectric vibration element, a lid body 3 for hermetically sealing the container body, a container body 1, It is comprised by the sealing material layer 4 for joining the cover body 3. FIG.

  The container body 1 is formed by laminating a plurality of insulating layers made of a ceramic material such as alumina ceramics or glass-ceramics. On the surface, element connection electrode pads 5 for mounting the crystal resonator element 2 are formed. An enclosure 13 is formed in the container body 1 so as to surround the space 11 in which the crystal resonator element 2 is mounted, and a groove 9 is formed outside the enclosure 13 so as to surround the enclosure 13. An annular conductor pattern 6 is formed on the bottom surface of the groove 9, and a plurality of external connection terminal electrodes 7 including an input terminal, an output terminal, and a ground terminal are provided on the outer bottom surface of the container body 1. .

  The pair of element connection electrode pads 5 provided in the container body 1 are electrically connected to excitation electrodes of the crystal resonator element 2 described later on the upper surface side thereof via the conductive adhesive material 8. It is electrically connected to input / output terminals (input terminals, output terminals) via internal via conductors. Further, a conductor pattern 6 is provided on the bottom surface of the groove portion 9, and is electrically connected to a lid 3 to be described later on the upper surface side of the conductive pattern 6 via a sealing material layer 4, and a container body on the lower surface side. 1 is electrically connected to the ground terminal of the external connection terminal electrode 7 on the outer bottom surface of the container body 1 via a via conductor or the like inside.

  The crystal resonator element 2 mounted on the container body 1 is formed by attaching and forming a pair of excitation electrodes on both main surfaces of a crystal piece cut and polished at a predetermined angle from each crystal axis from an artificial crystal. When a fluctuation voltage from the outside is applied to the crystal piece through a pair of excitation electrodes, vibration with a predetermined frequency is caused in a certain vibration mode. Such a quartz crystal resonator element 2 is electrically and mechanically connected via a conductive adhesive 8 between the excitation electrodes attached to both main surfaces thereof and the corresponding element connection electrode pads 5 on the surface of the container body 1. Are connected to the container body 1 by being connected to each other. The conductive adhesive 8 is made by adding and mixing a predetermined amount of conductive particles made of Ag or the like into a resin material made of silicon resin or polyimide resin.

  Then, a lid 3 having substantially the same shape as the outer peripheral shape of the container body 1 is attached to the conductor pattern 6 via a sealing material layer 4 such as gold-tin (Au—Sn), and laser light is placed on the container body 1. The sealing material layer 4 is heated and melted by an annular lamp or a halogen lamp, and the space 11 in which the crystal resonator element 2 inside the sealing material layer 4 is mounted is hermetically sealed. . Further, by forming the sealing material layer 4 in the groove portion 9 provided in the outer peripheral area of the container body 1, impact due to dropping or the like can be absorbed and relaxed by the relatively thick sealing material layer 4. Therefore, it is possible to maintain the reliability as a crystal resonator. In the above-described embodiment, the material using the gold tin (Au—Sn) brazing material is exemplified as the material of the sealing material layer 4, but a gold germanium (Au—Ge) material may be used. Absent.

  As the lid 3, 42 alloy, Kovar, phosphor bronze, or the like may be used, and a Ni or Au metal layer is formed on the surface of the lid 3. The lid 3 is for accommodating the crystal resonator element 2 in a space surrounded by the enclosure 13 and hermetically sealing the container 3, and the container body 1 via the conductor pattern 6 and the sealing layer 4 described above. It is connected to the ground terminal of the external connection terminal electrode 7 on the outer bottom surface. Therefore, when the crystal resonator is used, when the external connection terminal electrode 7 is used for connection to the external circuit mother board, the lid 3 is held at the ground potential, and the crystal resonator element 2 is attached to the lid 3. The shield effect provides good protection from unnecessary external electrical effects such as noise.

Next, a method for manufacturing the above-described piezoelectric device will be described with reference to FIGS. Here, FIGS. 3A and 3B are external perspective views for explaining step A and step B of the manufacturing method of the present invention.
(Process A)
First, as shown in FIGS. 3A and 3B, a master substrate 10 is prepared in which an enclosure 13 that forms a space in which the crystal resonator element 2 is accommodated is formed in each device formation region A. Such a master substrate 10 is formed of a ceramic material such as glass-ceramic or alumina ceramic. The master substrate 10 is integrally formed by arranging a plurality of rectangular device forming areas A and abandoned areas B adjacent to each other, and one main surface side is surrounded by a surrounding body 13. A broken space 11 is provided. In the device forming region A, a groove 9 is formed between the surrounding body 13 and the outer periphery of the device forming region A, and a conductive pattern 6 is formed on the inner surface of the groove 9. 3 is an example in which four device formation areas A are arranged in a matrix of 2 rows × 2 columns, and a replacement area B is arranged between the adjacent device formation areas AA. Is shown. Further, in the捨代region B, injecting a sealing material (FIG. 3 (a)), or to place (FIG. 3 (b)) for the inlet portion 12 is formed.

(Process B)
As shown in FIGS. 3A and 3B, the sealing material layer 4 is formed in the groove portion 9 provided in the device formation region A of the master substrate 10. As shown in FIG. 3A, the sealing material layer 4 is injected with a sealing material such as gold tin (Au—Sn) into the injection port portion 12 provided in the disposal region B of the master substrate 10. It is formed by hardening after filling the groove 9. Further, as shown in FIG. 3B, a solid sealing material is disposed in the injection port portion 12, and this sealing material is heated and melted to fill each groove portion 9 and then re-cured, thereby sealing the sealing material. The layer 4 may be formed.

FIG. 4 is an external perspective view for explaining step C in the manufacturing method of the present invention.
(Process C)
Next, the crystal resonator element 2 is mounted in the space portion 11 of each device formation region A of the master substrate 10. At this time, the excitation electrode of the crystal resonator element 2 and the element connection electrode pad 5 on the inner bottom surface of the space portion 11 are electrically and mechanically connected via the conductive adhesive 8. Then, a master lid 14 formed by integrally arranging a plurality of lids 3 in a matrix on the upper surface of the encapsulant layer 4 is disposed, and each encapsulant layer 4 is connected to each encapsulant layer 4 by a halogen lamp, a xenon lamp, or the like. Join. The master lid 14 is manufactured by forming a metal such as 42 alloy into a predetermined shape using a conventionally known metal processing method.

FIG. 5 is an external perspective view for explaining step D in the manufacturing method of the present invention.
(Process D)
And finally, as shown in FIG. 5, each device formation area A is abandoned area by cutting the part where the master substrate 10 , the sealing material layer 4, and the master lid 14 are overlapped. By separating from B, individual crystal resonators are formed. The master substrate 10 and the like are cut by dicing using a dicer or the like, and a plurality of crystal resonators are obtained simultaneously.

  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, a material using a quartz crystal as an example of the material of the piezoelectric vibration element is illustrated. However, in addition to the crystal, lithium tantalate, lithium niobate, or piezoelectric ceramic is used as long as the material has a piezoelectric effect. It doesn't matter. In the above-described embodiment, the crystal resonator using the crystal resonator element is exemplified and described as the piezoelectric device. However, an integrated circuit element including the piezoelectric resonator element and an oscillation circuit electrically connected thereto is mounted on the container body. Such a piezoelectric oscillator may be used. Furthermore, the present invention can also be applied to the case where another piezoelectric vibration element such as a surface acoustic wave (SAW) filter is used as the piezoelectric vibration element.

FIG. 1 is an exploded perspective view illustrating a crystal resonator which is one of piezoelectric devices in a piezoelectric device manufactured by the manufacturing method of the present invention. FIG. 2 is a cross-sectional view showing a form after the crystal resonator disclosed in FIG. 1 is assembled. FIG. 3 is an external perspective view for explaining step A and step B of the manufacturing method of the present invention, and (a) shows a mode in which a sealing material for forming a sealing material layer is applied to the inlet portion. (B) shows the form which arrange | positions the sealing material which forms a sealing material layer in an injection port part. FIG. 4 is an external perspective view for explaining step C of the manufacturing method of the present invention. FIG. 5 is an external perspective view for explaining step D of the manufacturing method of the present invention. FIG. 6 is a cross-sectional view of a conventional crystal resonator (piezoelectric device).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Container body 2 ... Quartz crystal vibration element (piezoelectric vibration element)
DESCRIPTION OF SYMBOLS 3 ... Cover body 4 ... Sealing material layer 5 ... Electrode pad for element connection 6 ... Conductor pattern 7 ... Terminal electrode for external connection 8 ... Conductive adhesive 9 ... Groove 10 ... Master substrate 11 ... Space 12 ... Inlet 13 ... Go body
14 ... Master lid
A ... Device formation area
B ... Disposal area

Claims (1)

In a method for manufacturing a piezoelectric device, in which at least a piezoelectric vibration element is mounted in a recessed space formed on a substrate, and the recessed space is hermetically sealed by a lid disposed on an opening of the recessed space.
A concave space portion surrounded by a surrounding body is provided on the front main surface inside the rectangular device forming region, and a groove portion is provided outside the surrounding body, and the outer periphery of the groove portion is It coincides with the outer periphery of the device forming region, and a marginal area is provided on the outer periphery of each device forming region, and an inlet port connected to the groove is provided in the marginal region, A step A of forming a master substrate integrally formed by arranging a plurality of device forming regions and the abandoned regions in a matrix shape;
A step B of filling a sealing material made of a brazing material of gold tin or gold germanium into the groove portion from the inlet portion to form a sealing material layer;
A piezoelectric vibration element is mounted in the space, and then a plurality of lids corresponding to each of the device formation region and the abandonment region are arranged in a matrix on the sealing material layer and integrally formed. A step C for disposing a master lid that is sealed, and sealing the space portion by airtightly joining the sealing material layer and the master lid;
And a step D of cutting a portion where the master substrate, the sealing material layer, and the master lid are overlapped to obtain a plurality of piezoelectric devices at the same time. Manufacturing method.

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