JP2009246781A - Method of manufacturing piezoelectric device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a piezoelectric device by which productivity of the piezoelectric device is improved without incurring any position deviation upon forming a sealing layer. <P>SOLUTION: In a piezoelectric device, a piezoelectric vibration element is mounted in a container having a recessed space formed of a frame and a substrate and having a piezoelectric vibration element mounting pad inside the recessed space and the inside of the recessed space is hermetically sealed with a cover. The method of manufacturing the piezoelectric device includes: a recess forming process of forming a recess in at least one corner of the frame; a sealing member placing process of placing a sealing member in the recess; and a sealing layer forming process of forming a sealing layer on a sealing conductor pattern provided on an opening-side top surface of the frame of the container by fusing the sealing member. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a piezoelectric device used in an electronic apparatus or the like.

FIG. 6 is a cross-sectional view showing a conventional piezoelectric device. FIG. 7 is an external perspective view showing a sealing material layer forming step which is a conventional method for manufacturing a piezoelectric device.
As shown in FIG. 6, as an example of a conventional piezoelectric device, a quartz crystal resonator 200 using quartz as a piezoelectric material is shown. The crystal resonator 200 is mainly composed of a container body 201 having a recessed space 202, a crystal resonator element 205, and a lid body 206.
The container body 201 includes a substrate part 201a and a frame part 201b. A pair of crystal resonator element mounting pads 203 are provided on the substrate portion 201 a in the recessed space 202 formed in the container body 201.
On the crystal vibration element mounting pad 203, a crystal vibration element 205 having a pair of excitation electrodes electrically connected via a conductive adhesive 204 on the front and back main surfaces is mounted.
A sealing material layer 208 is provided on the top surface of the frame portion 201 b of the container body 201 that surrounds the crystal resonator element 205.
The sealing material layer 208 is covered with a metal lid 206, and the sealing material layer 208 and the lid 206 are bonded to each other to be hermetically sealed.

As a method for manufacturing a piezoelectric device, as shown in FIG. 7, a ring-shaped sealing member 209 is placed on the sealing conductor pattern 207 provided on the opening side top surface of the frame 201 b of the container body 201. There is known a method for manufacturing a piezoelectric device in which a sealing member 209 is disposed and melted to melt and spread on the sealing conductor pattern 207 to form a sealing material layer 208 (for example, Patent Documents). 1).
JP 2007-36970 A

However, in the conventional method for manufacturing the piezoelectric device 200, the plate-shaped sealing member 209 is punched into a ring shape, and the ring-shaped sealing member 209 is formed on the sealing conductor pattern 207 of the frame portion 201b of the container body 201. The sealing material layer 208 is formed by arranging and melting the ring-shaped sealing member 209 on the sealing conductor pattern 207 of the frame portion 201b and melting the ring. There existed a subject that the sealing member 209 of a form caused a position shift.
As described above, since the sealing member 209 is displaced, the sealing material layer 208 is also formed while being displaced, so that there is no sealing material layer 208 on the sealing conductor pattern or very much. There was also a problem that a small number of parts were formed, and hermetic sealing could not be performed.

  Further, since the ring-shaped sealing member 209 is thin and the center is punched, the ring-shaped sealing member 209 is disposed when the ring-shaped sealing member 209 is disposed on the sealing conductor pattern 207 of the frame 201b of the container body 201. There is also a problem that productivity is reduced because the nozzle is easily damaged by contact with a nozzle, a package, and the like.

  Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a method for manufacturing a piezoelectric device that improves the productivity of the piezoelectric device without causing displacement when forming a sealing material layer. And

  The method for manufacturing a piezoelectric device of the present invention includes mounting a piezoelectric vibration element in a container body having a recessed space formed by a frame portion and a substrate portion, and a piezoelectric vibration element mounting pad provided in the recessed space. A method of manufacturing a piezoelectric device in which the inside of the recessed space is hermetically sealed with a lid, wherein a recessed portion forming step for forming a recessed portion in at least one corner of the frame portion, and a sealing member is disposed in the recessed portion And a sealing material layer forming step of melting the sealing member and forming a sealing material layer on the sealing conductor pattern provided on the opening side top surface of the frame portion of the container body. It is characterized by having.

  Further, the recess is formed so as to be located diagonally at the corner of the frame.

According to the method for manufacturing a piezoelectric device of the present invention, by having a hollow portion forming step of forming a hollow portion in at least one corner of the frame portion, and a sealing member arrangement step of arranging a sealing member in the hollow portion, Since the sealing member is fitted in the recess, it is possible to prevent displacement of the sealing member when the sealing member melts.
In addition, the sealing member is disposed in the depression, and heat is applied in a state where the sealing member is not displaced, so that the sealing member wets and spreads on the conductor pattern for sealing, and a sealing material layer is formed. Therefore, the sealing material layer can also be formed without causing a positional shift.

  In addition, since it is not necessary to punch the sealing member into a thin ring shape, when the sealing member is disposed in the hollow portion of the frame portion of the container body, it may be damaged even if it comes into contact with the nozzle or package for placement. Therefore, productivity of the piezoelectric device can be improved.

  Further, since the recess is formed so as to be diagonally located at the corner of the frame portion, when the sealing member is disposed in the recess and melted, the sealing material layer is formed with a uniform thickness. Can be formed.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. A case where quartz is used for the piezoelectric vibration element will be described.
FIG. 1 is an external perspective view showing a piezoelectric device according to an embodiment of the present invention. 2 is a cross-sectional view taken along the line AA in FIG. 3 is a cross-sectional view taken along the line BB of FIG.
Hereinafter, a crystal resonator which is an example of a piezoelectric device will be described.

  A crystal resonator 100 shown in FIGS. 1 to 3 mainly includes a container body 10, a crystal resonator element 20, and a lid body 30. In this quartz crystal resonator 100, roughly, a quartz vibrating element 20 is mounted in a recessed space 11 formed on one main surface of the container body 10, and a sealing conductor pattern of the container body 10 is provided. 12 has a structure in which a sealing material layer 16 provided on 12 and a lid 30 are joined.

As shown in FIGS. 1 and 2, the crystal resonator element 20 is formed by adhering and forming an excitation electrode 22 on a crystal element plate 21, and an alternating voltage from the outside passes through the excitation electrode 22 to generate a crystal element plate. When applied to 21, excitation occurs in a predetermined vibration mode and frequency.
The quartz base plate 21 is a substantially flat plate shape that is cut from an artificial crystalline lens at a predetermined cut angle and is subjected to outer shape processing, and has a planar shape of, for example, a quadrangle.
The excitation electrode 22 is deposited and formed on both the front and back main surfaces of the quartz base plate 21. Such a crystal resonator element 20 includes an excitation electrode 22 attached to both main surfaces thereof and a piezoelectric resonator element mounting pad 13 formed on the bottom surface of the recessed space 11 via a conductive adhesive 40. Then, it is mounted in the recessed space 11 by being electrically and mechanically connected.

The container body 10 includes a substrate portion 10a and frame portions 10b and 10c provided on one main surface of the substrate portion 10a.
For example, the container body 10 is formed by laminating a plurality of substrate portions 10a and frame portions 10b and 10c made of a ceramic material such as alumina ceramic or glass-ceramic.
As shown in FIG. 2, a concave space 11 is formed by one main surface of the substrate portion 10a and the frame portions 10b and 10c, and a hollow portion 15 (see FIG. 4) is formed by the frame portion 10b and the frame portion 10c. ing.
A sealing conductor pattern 12 is formed on the entire periphery of the opening-side top surface of the frame portion 10 c surrounding the recessed space 11 of the container body 10 and inside the recess portion 15.
That is, the sealing conductor pattern 12 is formed in the opening-side top surface of the frame portion 10c and in the hollow portion 15 formed by the frame portion 10b and the frame portion 10c. Therefore, the sealing material layer 16 is formed on the surface of the sealing conductor pattern 12.
In addition, the sealing material layer 16 is also formed in the recess 15.
A piezoelectric vibration element mounting pad 13 is provided on the substrate portion 10 a in the recessed space 11.
External connection electrode terminals 14 are provided at the four corners of the other main surface of the substrate portion 10 a constituting the container body 10.
The piezoelectric vibration element mounting pad 13 and the external connection electrode terminal 14 include a wiring pattern (not shown) formed in the substrate portion 10a in the recessed space 11 of the container body 10, and vias formed in the substrate portion 10a. They are connected by a conductor (not shown).

The hollow portion 15 is formed by a frame portion 10b that is a bottom surface of the hollow portion 15 and a frame portion 10c that is disposed on the frame portion 10b and that is a side surface of the hollow portion 15, and is provided at least one corner of the container body 10. It has been.
The depression 15 is formed so as not to be displaced when a sealing member 50 described later is disposed. By applying heat to the sealing member 50, the sealing member 50 wets and spreads on the sealing conductor pattern 12, and the sealing material layer 17 is formed on the sealing conductor pattern 12.

The sealing conductor pattern 12 is formed on the entire circumference of the opening-side top surface of the frame portion 10 c of the container body 10 and the inner surface of the recess portion 15.
This sealing conductor pattern 12 is for forming a sealing material layer 16 on the sealing conductor pattern 12 by improving the wettability of a sealing member 50 described later.
The sealing conductor pattern 12 has, for example, a nickel (Ni) layer and a gold (Au) layer sequentially formed on the surface of a base layer made of tungsten (W), molybdenum (Mo), etc., and the recess space 11 is formed in an annular shape. It is formed to a thickness of 10 μm to 25 μm by being deposited in a surrounding form.

The sealing member 50 has such a shape that it can be disposed in the recess 15 and is formed by punching a brazing material such as gold tin (Au—Sn).
For example, the component ratio of gold tin brazing material (Au—Sn) is 80% gold and 20% tin.
The shape of the sealing member 50 is adapted to the shape of the recess 15 and may be a columnar shape or a quadrangular prism shape.
Further, the sealing member 50 is formed longer than the depth of the recess 15. That is, the sealing member 50 is melted and provided so as to protrude on the conductive pattern 12 for sealing.

The sealing material layer 16 is formed along the conductor pattern 12 for sealing by applying heat to the sealing member 50. The thickness of the sealing material layer 16 is 10 μm to 40 μm.
This sealing material layer 16 is for joining with the lid body 30 mentioned later and airtightly sealing the inside of the recessed space 11.

  The piezoelectric vibration element mounting pad 13 connected to the excitation electrode 21 and a predetermined terminal among the external connection electrode terminals 14 have a portion formed in the substrate portion 10 a in the recessed space 11 of the container body 10. A wiring pattern (not shown) is connected to a via conductor (not shown) formed inside the substrate portion 10a.

  The conductive adhesive 40 contains a conductive filler in a silicone resin or an epoxy resin. Examples of the conductive powder include aluminum (Al), molybdenum (Mo), tungsten (W), and platinum. A material including any one of (Pt), palladium (Pd), silver (Ag), titanium (Ti), nickel (Ni), nickel iron (NiFe), or a combination thereof is used.

The lid 30 is joined to the sealing material layer 16 provided on the opening side top surface of the frame 10 b of the container body 10.
The lid 30 is manufactured by adopting a conventionally known metal processing method and shaping a metal such as 42 alloy into a predetermined shape. A nickel (Ni) layer is formed on the surface of the lid 30.

Next, a method for manufacturing a piezoelectric device according to an embodiment of the present invention will be described with reference to FIG.
Here, FIG. 4A is a perspective view showing a recess forming step of the method for manufacturing a piezoelectric device according to the embodiment of the present invention, and FIG. 4B is a piezoelectric device according to the embodiment of the present invention. FIG. 4C is a perspective view showing a sealing material layer forming step of the piezoelectric device manufacturing method according to the embodiment of the present invention.

(Indentation forming step)
As shown in FIG. 4A, the hollow portion forming step is a step of forming the hollow portion 15 in the container body 10 when the container body 10 is formed.
The container body 10 is formed as follows. When the substrate portion 10a and the frame portions 10b and 10c are made of alumina ceramics, a sheet for forming each is formed, and the sealing conductor pattern 12, the piezoelectric vibration element mounting pad 13, and the external connection are formed on the sheet to be the substrate portion 10a. A conductor paste to be used as the electrode terminal 14 and the like is applied by well-known screen printing, and a ceramic green sheet is punched out to apply a conductor paste to be a via conductor in a predetermined through hole.
Next, a sheet to be the frame portion 10b is formed. And the sheet | seat used as the frame part 10c is formed. The sheet of the frame portion 10c is provided with a hole that becomes the recess 15.
These are stacked with the frame portion 10b on the substrate portion 10a, the frame portion 10c is stacked on the frame portion 10b, press-molded, and then fired at a high temperature to produce a sheet serving as the container body 10.
Moreover, the hollow part 15 is formed in the column shape and the square pillar shape.
A sealing conductor pattern 12 is provided on the opening-side top surface of the frame 10 c of the container body 10 and the recess 15.

(Sealing member placement process)
FIG. 4B is a process of arranging the sealing member 50 in the recess 15 formed in the frame part 10 c of the container body 10.
The sealing member 50 has a cross-sectional shape that matches the cylindrical shape, quadrangular prism shape, or the like, which is the shape of the recessed portion 15, and is formed longer than the depth of the recessed portion 15. Is also provided protruding. That is, the sealing member 50 is provided so as to project the amount of the wet spreading on the sealing conductor pattern 12.

(Encapsulant layer forming process)
The sealing material layer forming step is a step of melting the sealing member 50 and forming the sealing material layer 16 on the sealing conductor pattern 12 provided on the opening side top surface of the frame portion 10c of the container body 10. is there.
By applying heat to the sealing member 50 disposed in the recess 15, the sealing member 50 is melted and the sealing material layer 16 is formed on the sealing conductor pattern 12.
That is, the sealing member 50 protruding from the sealing conductor pattern 12 spreads on the sealing conductor pattern 12 which is melted by heat of 280 ° C. to 300 ° C., and is sealed on the entire surface of the sealing conductor pattern 12. Layer 16 is formed.
The encapsulant layer 16 is formed by cooling the container body 10 after applying heat of 280 ° C. to 300 ° C. The thickness of the sealing material layer 16 at that time is 10 μm to 20 μm.

(Quartz crystal element mounting process)
Two pairs of piezoelectric vibration element mounting pads 13 are provided on the substrate portion 10 a in the recessed space 11 of the container body 10, and a conductive adhesive 40 is applied to the piezoelectric vibration element mounting pads 13.
The excitation electrode 22 attached to both main surfaces of the piezoelectric vibration element 20 and the piezoelectric vibration element mounting pad 13 formed on the inner bottom surface of the recessed space 11 are electrically and mechanically connected via a conductive adhesive 40. Are connected to the recessed space 11 by being connected to each other.

(Cover body joining process)
The lid body 30 is placed on the sealing material layer 16 so as to cover the opening of the recessed space 11 of the container body 10, and the lid body 30 is removed from the container body by melting the sealing material layer 16 of the container body 10. 10 sealing material layers 16 are bonded. Thus, a crystal resonator as a piezoelectric device is obtained.
For example, as a heating unit, the lid 30 is bonded to the sealing material layer 16 of the container body 10 by irradiating a heat source such as a xenon lamp or a halogen lamp.
The heating temperature at this time is 300 ° C. to 320 ° C., which is higher than the temperature at which the sealing material layer 16 is formed.

According to the method for manufacturing a piezoelectric device of the present invention, there is a recess forming step for forming the recess 15 in at least one corner of the frame portion, and a sealing member arranging step for disposing the sealing member 50 in the recess 15. As a result, the sealing member 50 is in a state of being disposed in the recess 15, so that the sealing member 50 can be prevented from being displaced.
Further, the sealing member 50 is disposed in the depression 15 and heat is applied in a state where the sealing member is not displaced, so that the sealing member 50 spreads evenly along the sealing conductor pattern 12. Since the sealing material layer 16 is formed, the sealing material layer 16 can also be formed without causing displacement.
In addition, since the sealing member 50 is punched into a shape that matches the recess 15, it is not necessary to punch into the ring form, and it is possible to prevent the sealing member 50 from being damaged. Can be improved.
Further, the recess 15 is formed to be diagonally positioned at the corner of the frame 10c, so that when the sealing member 50 is placed in the recess 15 and melted, the sealing material layer 16 Can be formed with a uniform thickness.

In addition, this invention is not limited to the said 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 crystal is used as the piezoelectric material constituting the piezoelectric vibration element 20 has been described. However, as other piezoelectric materials, lithium niobate, lithium tantalate, or piezoelectric ceramics is used as the piezoelectric material. The piezoelectric vibration element used may be used.

(Modification)
Fig.5 (a) is an external appearance perspective view which shows the modification of the container body of the piezoelectric device which concerns on other embodiment of this invention. FIG.5 (b) is an external appearance perspective view which shows the modification of the container body of the piezoelectric device which concerns on other embodiment of this invention. FIG.5 (c) is an external appearance perspective view which shows the modification of the container body of the piezoelectric device which concerns on other embodiment of this invention.
As shown to Fig.5 (a), the container body 10 is good also as a structure which provided the hollow part 15 in one of four corners.
As shown in FIG. 5B, the container body 10 may have a structure in which the recessed portions 15 are provided at three of the four corners.
As shown in FIG. 5C, the container body 10 may have a structure in which the recessed portions 15 are provided in four of the four corners.
Thus, even if it shows to Fig.5 (a)-FIG.5 (c), there exists an effect similar to embodiment.

  Further, in the above-described embodiment, the crystal resonator which is one of the piezoelectric devices has been described as an example, but instead of this, the piezoelectric vibration element 20 and the piezoelectric vibration are placed in the recessed space 11 of the container body 10. Together with the integrated circuit element having the oscillation circuit electrically connected to the element 20 or a separate recessed space 11 formed in the container body 10, the piezoelectric vibrating element 20 and the integrated circuit element are formed in the recessed space 11. The present invention can also be applied to other piezoelectric devices such as a piezoelectric oscillator in which the piezoelectric oscillator is separately mounted and a piezoelectric filter in which the piezoelectric vibration element 20 mounted inside functions as a filter.

It is a disassembled perspective view which shows a piezoelectric vibrator as a piezoelectric device which concerns on embodiment of this invention. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. (A) is a perspective view which shows the hollow part formation process of the manufacturing method of the piezoelectric device which concerns on embodiment of this invention, (b) is the sealing member of the manufacturing method of the piezoelectric device which concerns on embodiment of this invention It is a perspective view which shows an arrangement | positioning process, (c) is a perspective view which shows the sealing material layer formation process of the manufacturing method of the piezoelectric device which concerns on embodiment of this invention. (A) is an external appearance perspective view which shows the modification of the container body of the piezoelectric device which concerns on other embodiment of this invention, (b) is the container body of the piezoelectric device which concerns on other embodiment of this invention. It is an external appearance perspective view which shows a modification, (c) is an external appearance perspective view which shows the modification of the container body of the piezoelectric device which concerns on other embodiment of this invention. It is sectional drawing which shows the conventional piezoelectric device. It is an external appearance perspective view which shows the sealing material layer formation process of the manufacturing method of the conventional piezoelectric device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Container body 10a ... Board | substrate part 10b, 10c ... Frame part 11 ... Recessed space 12 ... Conductive pattern for sealing 13 ... Piezoelectric vibration element mounting pad 14 ... External connection Electrode terminal 15 ... Depression 16 ... Sealing material layer 20 ... Piezoelectric vibration element (crystal vibration element)
DESCRIPTION OF SYMBOLS 21 ... Crystal base plate 22 ... Excitation electrode 30 ... Lid 40 ... Conductive adhesive 50 ... Sealing member

Claims (2)

A piezoelectric vibration element is mounted on a container body having a recessed space formed by a frame portion and a substrate portion, and a piezoelectric vibration element mounting pad is provided in the recessed space, and the inside of the recessed space is covered with a lid. A method of manufacturing a hermetically sealed piezoelectric device comprising:
A recess forming step for forming a recess in the frame; and
A sealing member arrangement step of arranging a sealing member in the recess,
A sealing material layer forming step of melting the sealing member and forming a sealing material layer on the sealing conductor pattern provided on the opening side top surface of the frame portion of the container body. A method for manufacturing a piezoelectric device.   The method for manufacturing a piezoelectric device according to claim 1, wherein the recess is formed so as to be diagonally positioned at a corner of the frame.

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