JPH098593A - Oscillator and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a vibrator and a manufacturing method thereof, and an object thereof is to prevent deterioration of vibration characteristics. In order to achieve this object, the present invention provides
The excitation electrodes 8 and 9 of the vibrating portion 7 are configured by providing Ti layers 8b and 9b below the Au layers 8a and 9a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrator such as a crystal and a method for manufacturing the vibrator.

[0002]

2. Description of the Related Art A conventional vibrator of this type includes a vibrating plate and first and second covers which cover the front and back surfaces of the vibrating plate and sandwich the outer peripheral portion of the vibrating plate at its outer peripheral portion. Prepared,
The vibrating plate had a tongue-shaped vibrating portion inside a portion sandwiched by the first and second covers, and excitation electrodes were formed on the front and back surfaces of the vibrating portion. In addition, the excitation electrode is provided under the Au layer with C in order to improve the adhesion between Au and the diaphragm.
It was formed by providing the r layer.

[0003]

When the diaphragm and the first or second cover in the above-mentioned conventional example are joined, or the first or second cover joined to the diaphragm is annealed, When quartz is used, it is performed by heating in an atmosphere at 500 ° C. lower than the phase transition point. During this heating, Cr in the lower layer of the excitation electrode violently diffuses into Au in the upper layer, Oxidize on the surface of Au, and at this time, protrusions having a height of 3000 to 5000 angstroms are formed on the surface. These protrusions cause deterioration of the vibration characteristics of the vibrator.Because an oxide film layer is formed on the surface of the excitation electrode, the resistance value when extracting the electrode to the outside through the through hole provided in the cover increases. As a result, the Ci value is increased.

Therefore, an object of the present invention is to prevent the vibration characteristic from deteriorating and to prevent the Ci value from increasing.

[0005]

In order to achieve this object, the present invention suppresses oxidation on the surface due to heat treatment by providing a Ti electrode below the Au layer for the excitation electrode. At this time, by setting the Ti film thickness to 500 angstroms or less, the deterioration of the Ci value can be further suppressed. In addition, heat treatment is performed at 5.0 × 10 ^-5 T
By carrying out in a high vacuum atmosphere of orr or lower, it is possible to further suppress the lower layer Ti from diffusing to the surface and oxidizing.

[0006]

According to the above means, Ti is more A than Cr
Since it is difficult to diffuse in u and is not easily oxidized on the surface, it is possible to suppress the oxidation on the surface of the excitation electrode due to the heat treatment. As a result, no protrusion is formed on the surface of the excitation electrode after the heat treatment, and it is possible to prevent deterioration of the vibration characteristics of the vibrator. At this time, if the film thickness of Ti is set to 500 angstroms or less, the amount of Ti diffused into Au due to the heat treatment is reduced, so that the specific resistance of the excitation electrode can be reduced, and the Ci value of the vibrator is not deteriorated. Can be prevented. Further, in order to reduce the partial pressure of oxygen in the atmosphere during heating, which is the cause of this oxidation, heat treatment is performed in a high vacuum atmosphere of 5.0 × 10 ⁻⁵ Torr or less, so that the oxidation electrode surface is oxidized. It can be further suppressed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 is a vibrating plate having a plate thickness of 100 μm.
It is composed of a quartz plate. On the front and back of the diaphragm 1,
The covers 2 and 3 made of a crystal plate having a plate thickness of 400 μm are bonded by direct bonding of the crystals while being heated and pressed at a temperature lower than the phase transition point of the crystals. The external electrodes 4, 5 in FIG. 1 are arranged on both sides of the back surface of the cover 3. As shown in FIGS. 2 and 3, the vibrating plate 1 has a U-shaped cut groove 6 formed inward thereof, thereby forming a tongue-shaped vibrating portion 7. Excitation electrodes 8 and 9 are formed on the front and back surfaces of the vibrating portion 7, and lead electrodes 11 and 12 thereof are drawn out via a root portion 10 of the vibrating portion 7, respectively. As shown in FIGS. 2 to 5, the end portion of the inner lead electrode 11 forms the through hole 13 in the diaphragm 1.
3, and then extended to the opposite side of the base 10 through the side of the vibrating part 7 as shown in FIG. Further, the lead electrode 12 forms a connection portion 15 on the base portion 10 side. Then, the through hole 1 formed in the cover 3 corresponding to these connecting portions 14 and 15
The external electrodes 4 and 5 are connected via the conductors 18 in 6 and 17, respectively. It should be noted that the covers 2 and 3 sandwich the front and back outer peripheral portions of the diaphragm 1 at their outer peripheral portions, and are directly joined, but they are joined at the outer peripheral portion of the kerf 6 of the diaphragm 1. That is, the portion where the lead electrode 11 passes through the side of the vibrating portion 7 is joined to the cover 3 on the outside thereof. Thus, in order to form the lead electrode 11 on the side of the vibrating portion 7 on the rear surface side of the vibrating plate 1 as described above, as shown in FIGS. The plate thickness is made thick only at the sandwiching portion between and, and the plate thickness is made thin at the portions where the vibrating portion 7 and the lead electrodes 11 and 12 are formed by etching. FIG. 4 clearly shows the diaphragm 1 after the etching step, and the thickness of the rear surface portion corresponding to the frame line 19 is reduced by etching. Also,
The outer peripheral portion of the frame line 19 is a portion sandwiched and joined by the covers 2 and 3, and as is clear from FIG. 4,
The holding width 20 on the longitudinal side of the diaphragm 1 is made wider than the holding width 21 on the short side.

Since the lead electrode 11 is provided on the side of the vibrating portion 7 as shown in FIG.
Is shifted from the center of the diaphragm 1 to one side.

The cut groove 6 in the root portion 10 has a semicircular shape as shown in FIG. 4, so that cracks are less likely to occur even when an excessive impact is applied.

The through holes 16 and 17 are provided by sandblasting the cover 3 in a single plate state, and have a substantially truncated cone shape. The cover 3 is washed with pure water after the sandblasting, and the surface and the through holes 16 and 17 are removed.
Remove dust inside. Then, the cover 3 and the quartz diaphragm 1 are joined together, and then heat treatment is performed for 1 hour at 500 ° C. lower than 573 ° C. which is the phase transition point of the quartz cover 3 (in this case, the expression of annealing is Which is more appropriate, and will be referred to as annealing hereinafter). As a result of this annealing, the through hole 1
The cracks formed on the inner wall surface during the formation of Nos. 6 and 17 will disappear.

During this annealing, 5.0 × 10 ^-5 Torr
By annealing in the following high vacuum, oxidation on the surfaces of the excitation electrodes 8 and 9 is suppressed, and deterioration of the oscillator characteristics is prevented.

FIG. 7 is a cross-sectional view of a main portion of the vibrating portion 7 of the diaphragm 1 and the excitation electrodes 8 and 9. The excitation electrode 8 has a laminated structure of Au layers 8a and 9a and Ti layers 8b and 9b thereunder. ，
9 is composed. The thickness of the Au layer 8a is 3000 to 5
By setting the thickness of the Ti layers 8b and 9b to 500 angstroms or less for 000 angstroms,
Further, oxidation on the surfaces of the excitation electrodes 8 and 9 is suppressed to prevent deterioration of characteristics.

[0013]

As described above, according to the present invention, since the excitation electrode of the vibrating portion is constituted by providing the Ti layer below the Au layer,
Oxidation on the surface of the excitation electrode after heat treatment can be suppressed, and formation of protrusions on the surface of the excitation electrode can be prevented,
As a result, it is possible to prevent the characteristics of the vibrator from deteriorating, and
It is possible to prevent the value from decreasing.

[Brief description of drawings]

FIG. 1 is a perspective view of one embodiment of the present invention.

FIG. 2 is an exploded perspective view thereof.

FIG. 3 is an exploded perspective view thereof.

FIG. 4 is a top view of the diaphragm.

5 is a sectional view of the vibrator in which covers 2 and 3 are joined to the vibrating plate of FIG.

6 is a cross-sectional view of the vibrator in which covers 2 and 3 are joined to the vibrating plate of FIG. 4;

FIG. 7 is a cross-sectional view of a main part of a vibrating part 7 of a diaphragm 1 and excitation electrodes 8 and 9.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vibration plate 2 Cover 3 Cover 4 External electrode 5 External electrode 6 Cut groove 7 Vibrating part 8 Excitation electrode 8a Au layer 8b Ti layer 9 Excitation electrode 9a Au layer 9b Ti layer 10 Root part 11 Lead electrode 12 Lead electrode 13 Through Hole 14 Connection part 15 Connection part 16 Through hole 17 Through hole 18 Conductor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiichiro Sakaguchi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A diaphragm, comprising: a diaphragm; first and second covers that cover the front and back surfaces of the diaphragm and sandwich the outer periphery of the diaphragm with the outer periphery thereof. The first and second covers have a tongue-like vibrating portion inside the nipping portion, and excitation electrodes are formed on the front and back surfaces of the vibrating portion.
Lead electrodes are drawn out from the excitation electrodes on the front and back sides through the roots of the vibrating portions, and the lead electrodes on the front and back sides are conductors provided in the through holes of the first or second cover. In the vibrator which is electrically connected to the first and second external electrodes via the vibrator, the excitation electrode is formed by providing at least a Ti layer below the Au layer. 2. The vibrator according to claim 1, wherein the excitation electrode is formed by providing a Ti layer of 500 angstroms or less under an Au layer of 3000 to 5000 angstroms. 3. The vibrating plate of the vibrator according to claim 1, and
Or, the one to which the second cover is joined is approximately 500 ° C,
A method of manufacturing a vibrator, comprising heating in an atmosphere having a vacuum degree of about 5.0 × 10 ⁻⁵ Torr or less.