JP3390348B2 - Quartz crystal resonator and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystal unit used for portable information equipment and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a conventional crystal oscillator, a structure is known in which a lid and a case are joined to the upper and lower surfaces of a frame-attached oscillator piece by soldering. (For example, JP-A-56-119518
(See the official gazette).

[0003]

In the conventional crystal unit, since low fusion metal such as solder or low melting point glass is used for joining the lid and the case, it is necessary to adjust the frequency when joining the lid and the case. There is a problem in that metal or organic matter is attached to the crystal resonator piece due to outgas generated by heating at the time, crystal impedance increases, and the frequency characteristic of the resonator deteriorates.

[0004]

According to the present invention, metal layers are provided on the upper surface and the lower surface of an outer frame formed integrally with a crystal unit, and the metal layer, the lid and the case are anodically bonded. Thus, by anodic-bonding the metal layer, the lid, and the case to each other, outgas is prevented from adhering to the crystal resonator piece and an increase in crystal impedance is prevented.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In a crystal resonator of the present invention, an outer frame integrally formed with a crystal resonator piece, a mounting electrode at the base of the crystal resonator piece, and a metal layer on the upper surface of the outer frame. A metal layer on the lower surface, and a lid having a concave portion on the surface facing the crystal oscillator piece, which is disposed on the upper surface of the outer frame via the metal layer,
A case is used which is disposed on the lower surface of the outer frame via the metal layer on the lower surface, has a recess on the surface facing the crystal resonator piece, and has a through hole electrically connected to the mounting electrode.

Glass is used for the lid and the case. Besides glass, quartz and silicon can also be used. Furthermore, it is preferable that the crystal has the same cut surface as the crystal resonator piece. Since the crystal resonator configured as described above does not use a sealant, it works so as not to cause an increase in crystal impedance due to outgas. Further, in the present invention, a crystal oscillator piece, an outer frame integrally formed with the crystal oscillator piece, thicker than a thickness of the crystal oscillator piece, a mounting electrode at a base portion of the crystal oscillator piece, and the external member. A metal layer on the upper surface of the frame and a metal layer on the lower surface, a lid arranged on the upper surface of the outer frame via the metal layer, and arranged on the lower surface of the outer frame via the metal layer on the lower surface, and A case having a through hole electrically connected to the mounting electrode is used.

By using the above-mentioned lid, case and crystal oscillator piece, the crystal oscillator can be made thin as a whole and its mechanical strength can be enhanced. Further, a step of forming a plurality of crystal oscillator pieces and an outer frame integrally connected to the crystal oscillator pieces on a first substrate made of crystal, and mounting electrodes on the crystal oscillator piece and a surface of the outer frame. Forming a metal layer on the
Forming a recess on the surface of the second substrate facing the upper surface of the crystal resonator piece; forming a recess on the surface of the third substrate facing the lower surface of the crystal resonator piece; The step of arranging the surface of the second substrate having the concave portion on the upper surface of the substrate and performing anodic bonding via the metal layer;
The quartz resonator is manufactured by the steps of disposing the surface of the third substrate having the concave portion on the upper surface of the substrate, performing anodic bonding through the metal layer, and cutting the outer frame. Through this process, the crystal unit can be manufactured on a wafer-by-wafer basis.

Finally, a step of forming a plurality of crystal oscillator pieces and an outer frame integrally connected to the crystal oscillator pieces on a first substrate made of crystal, and etching the crystal oscillator pieces to obtain a thickness. And a step of forming a metal layer on the surface of the mounting electrode and the outer frame on the crystal unit, the first
Placing a second substrate on the upper surface of the substrate and performing anodic bonding via the metal layer, and placing a third substrate on the upper surface of the first substrate and performing anodic bonding via the metal layer When,
A crystal oscillator is manufactured from the step of cutting the outer frame. As a result, a thin crystal resonator having high material strength for the lid and the case can be obtained.

Further, a piezoelectric vibrator using a SAW device, a mechanical filter or PZT can be manufactured by the same process.

[0010]

Embodiments will be described below with reference to the drawings. (Embodiment 1) In the embodiment shown in FIG. 1, a tuning fork type crystal resonator piece 60 and an outer frame 50 connected to one end of the crystal resonator piece 60 are formed on a quartz substrate by etching. Next, the mounting electrode 90 and the metal layers 30 and 40 are formed on the surfaces of the crystal unit 60 and the outer frame 50, respectively.

Next, the lid 10 made of glass having the recess 12 etched on the surface facing the upper surface of the crystal unit 60 is anodically bonded. Finally, the crystal unit 60
The case having the glass 70 having the concave portion 72 formed by etching on the surface facing the lower surface of 1 is anodically bonded. FIG. 2 is a diagram showing the crystal resonator piece 60 and the outer frame 50. The excitation electrode 80 is provided on the upper surface of one vibrating portion of the tuning fork type crystal resonator piece 60 and the excitation electrode 81 is provided on the upper surface of the other vibrating portion. Have. Here, the crystal oscillator piece 60 is integrally formed with the outer frame 60 via a base portion 65 that supports the vibrating portion.

FIG. 3 is a view showing a cross section taken along the line AA 'in FIG. The case 70 having the above, the crystal unit 60 having the excitation electrodes 81 and 83, the base 65 having the mounting electrodes 91 and 92, and the crystal unit 60 are formed integrally with the metal layers 30 and 40 on the surface. The outer frame 50 has.

FIG. 4 is a diagram showing an external electrode portion connected to the wiring on the circuit board. First, a case 70 having a tapered through hole 100 having a large opening toward the lower part of the case is arranged corresponding to the central portion of the attachment electrode 92 on the lower surface of the outer frame 50. Next, the outer electrode 1 including two layers of Cr and Au is formed on the inner surface of the through hole 70, the surface of the mounting electrode 92, and the surface of the case by sputtering.
Form 10.

(Example 2) As another example, in FIG. 5, a flat plate is used for the lid 10 and the case 70, and the thickness of the crystal unit 60 is made thinner than the thickness of the base portion 65 and the outer frame 50. Indicates. The crystal oscillator piece 60 has a thickness of the upper surface and the lower surface reduced by half etching. As a result, by using a flat plate for the lid 10 and the case 70, the mechanical strength of the entire crystal unit is increased, and it is possible to prevent deformation of the crystal unit used in a vacuum state such as a tuning fork type crystal unit. Lid 1
It is possible to prevent the destruction of the case 0 or the case 70 due to an external impact. Furthermore, the plate thickness of the lid 10 and the case 70 can be made thin, and as a result, a crystal oscillator having a small dimension in the height direction can be obtained.

(Embodiment 3) In FIG. 1, the lid 10 and the case 70 have the same plane orientation (cut surface) as the crystal oscillator piece 60.
It was formed of a crystal having. By forming a crystal having the same plane orientation, the coefficient of thermal expansion becomes the same as that of the crystal unit 60, so that twisting or bending due to heating and cooling during sealing or mounting does not occur, and reliability during mounting is high. Increase.

Example 4 A SAW device having an Al electrode formed on an AlN substrate was formed instead of the crystal unit shown in FIG. As a result, a SAW device having a smaller thickness than the conventional product could be formed.

[0017]

The present invention is carried out in the form as described above, and has the following effects. By combining the crystal unit and the metal layer, outgas from the low melting point metal can be prevented, so that the frequency characteristic of the crystal unit can be improved.

Since the use of lead contained in the solder can be stopped, environmental problems can be solved.
Further, it is possible to omit the conventional mounting step of the vibrator piece and the sealing agent film forming step, and the mounting and sealing steps of the vibrator piece can be integrated so that the manufacturing process can be shortened.

[Brief description of drawings]

FIG. 1 is a perspective view showing a crystal resonator of the present invention.

FIG. 2 is a top view showing a crystal resonator piece according to the present invention.

FIG. 3 is a cross-sectional view of a crystal unit according to the present invention.

FIG. 4 is a sectional view of an external electrode of the present invention.

FIG. 5 is a cross-sectional view showing another embodiment of the present invention.

[Explanation of symbols]

10 lid 12 recess 30 metal layers 40 metal layer 50 outer frame 60 crystal unit 65 base 70 cases 72 recess 80, 81, 83 Excitation electrode 90, 91, 92 mounting electrodes 100 through holes 110 external electrodes

Continued front page       (56) Reference JP-A-7-283676 (JP, A)                 Japanese Patent Laid-Open No. 7-66674 (JP, A)                 JP-A-6-303080 (JP, A)                 JP-A-6-310971 (JP, A)                 JP-A-6-303079 (JP, A)                 JP-A-5-199056 (JP, A)                 JP-A-56-44213 (JP, A)                 JP-A-53-23588 (JP, A)                 JP-A-6-283951 (JP, A)                 JP-A-4-284006 (JP, A)                 Japanese Patent Publication Sho 61-25249 (JP, B2)

Claims (5)

(57) [Claims] 1. A crystal oscillator piece and an outer frame are integrally formed.
The crystal substrate, the metal layers provided on the upper surface and the lower surface of the outer frame, and the concave portion are formed on the surface facing the upper surface of the crystal unit.
The lid and the bottom face of the crystal unit that has a concave
Is a case with, wherein the cover and the case, is formed of glass or silicon
And the crystal substrate and the lid are the upper surface of the outer frame.
Bonded by anodic bonding using the metal layer provided in
The crystal substrate and the case are provided on the lower surface of the outer frame.
Characterized by being joined by anodic bonding using a different metal layer
And a crystal unit. 2. A crystal unit and a thickness of the crystal unit.
A quartz substrate integrally formed with a thicker outer frame , metal layers provided on upper and lower surfaces of the outer frame, and a lid and a case provided so as to sandwich the quartz substrate.
When, wherein the cover and the case, is formed of glass or silicon
And the crystal substrate and the lid are the upper surface of the outer frame.
Bonded by anodic bonding using the metal layer provided in
The crystal substrate and the case are provided on the lower surface of the outer frame.
Characterized by being joined by anodic bonding using a different metal layer
And a crystal unit. 3. An excitation electrode and a mounting electrode are provided on the quartz substrate.
A case corresponding to the mounting electrode is provided on the case.
In addition, the taper shape becomes smaller toward the mounting electrode side.
Through hole is provided and the inner surface of the through hole is
An external power source is formed by sputtering so as to cover the mounting electrode.
The pole according to claim 1 or 2, wherein a pole is provided.
Mounted crystal unit. 4. A crystal unit on a first substrate made of crystal.
And forming an outer frame integrally connected to the crystal unit.
A step, a step of forming a metal layer on the surface of the outer frame, and a step of forming an attachment electrode on the first substrate made of the crystal.
And a recess is formed on the second substrate made of glass or silicon.
And the step of forming a recess in the third substrate made of glass or silicon
And a step of forming a tapered through hole in the third substrate.
And one surface of the crystal unit and the recess of the second substrate.
Are arranged so as to face each other, and anodic bonding using the metal layer
Bonding the first substrate and the second substrate by
And the other surface of the crystal unit and the recess of the third substrate.
Are facing each other, and the small size of the tapered through hole
Make sure that the opening on the bottom and the mounting electrode are in contact with each other.
The first substrate and the second substrate are arranged, and the metal layer is
The first substrate and the third substrate according to the anodic bonding used.
And a step of anodic bonding the first substrate and the third substrate,
Cover the inner surface of the through hole with the mounting electrode.
Method for manufacturing a quartz oscillator, characterized in that it comprises a step of forming external electrodes in sputtering, a. 5. A crystal resonator piece on a first substrate made of crystal.
And forming an outer frame integrally connected to the crystal unit.
Step, etching the quartz crystal piece on the first substrate,
A step of making the thickness of the crystal unit thinner than that of the outer frame, a step of forming a metal layer on the surface of the outer frame, and a step of forming a mounting electrode on the first substrate made of the crystal.
And a second substrate made of glass or silicon and the crystal oscillator.
The second substrate and the second substrate so that one surfaces of the armature pieces face each other.
Arranging the first substrate and anodic bonding using the metal layer
Bonding the first substrate and the second substrate by
And a taper on a third substrate made of glass or silicon.
The step of forming a through hole and the other surface of the crystal unit facing the third substrate.
And the smaller tapered through hole
Of the first electrode so that the opening of the
A substrate and the second substrate are arranged, and a positive electrode using the metal layer is arranged.
Bonding the first substrate and the third substrate by polar bonding
And a step of anodic bonding the first substrate and the third substrate,
Cover the inner surface of the through hole with the mounting electrode.
Method for manufacturing a quartz oscillator, characterized in that it comprises a step of forming external electrodes in sputtering, a.