JPH0918276A - Piezoelectric resonator and piezoelectric parts using the resonator - Google Patents

Abstract

PURPOSE: To prevent self-welding between an Ag electrode provided on the surface of a piezoelectric material substrate and a metallic terminal whose surface an Ag film brought into contact with this Ag electrode is provided on. CONSTITUTION: Metallic films 4 having a high melting point are formed on oscillation electrodes 3 which are provided on front and rear faces of a piezoelectric material substrate 2 and consist of Ag. Ni, Cr, W, Ti, Mo, Ni-Cu (Monel), or alloys of these metals is used as materials of these metallic films 4. It is preferable that the thickness of these metallic films 4 is about <=1/10 of the thickness of oscillation electrodes 3 or <=1μ.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric resonator, and more particularly to a piezoelectric resonator used when constructing an oscillation circuit, a filter circuit and the like, and a piezoelectric component using this piezoelectric resonator.

[0002]

2. Description of the Related Art As one type of piezoelectric component, one having a structure including a piezoelectric resonator and a metal terminal for holding the piezoelectric resonator is known. The piezoelectric resonator has a piezoelectric substrate and vibrating electrodes and extraction electrodes provided on the front and back surfaces of the piezoelectric substrate. These vibrating electrodes and extraction electrodes are usually made of Ag. On the other hand, the metal terminal is obtained by providing an Ag film on the surface of a plate material such as phosphor bronze by means such as plating. Then, the metal terminal is brought into contact with the vibrating electrode or the extraction electrode, and the piezoelectric resonator is held by the metal terminal.

[0003]

In the conventional piezoelectric component, both the vibrating electrode and the extraction electrode of the piezoelectric resonator and the surface coating film of the metal terminal are made of Ag. However, because Ag has a property of easily self-bonding,
Fusing may occur at the portion where the metal terminal is in contact with the vibrating electrode or the extraction electrode. In such a case, vibration energy generated when the piezoelectric resonator resonates is applied to the fusion-bonded portion of the metal terminal and the vibrating electrode, part of the vibrating electrode is peeled off from the piezoelectric substrate, and the vibrating electrode and the metal terminal There was a risk of poor continuity.

Therefore, an object of the present invention is to provide a piezoelectric resonator in which an Ag electrode provided on the surface of a piezoelectric substrate and a metal terminal provided with an Ag film contacting the Ag electrode on the surface are less likely to be fused together, and this piezoelectric resonance. It is to provide a piezoelectric component using a child.

[0005]

In order to achieve the above objects, a piezoelectric resonator according to the present invention comprises (a) a piezoelectric substrate and
(B) an Ag electrode provided on the surface of the piezoelectric substrate,
(C) a high melting point metal film provided on the surface of the Ag electrode,
It is characterized by having. The high melting point metal film is preferably elastically in contact with a metal terminal provided with an Ag film on its surface.

A piezoelectric component according to the present invention comprises (d) the piezoelectric resonator according to claim 1 or 2, and (e)
And a metal terminal having an Ag film on the surface thereof, which holds the piezoelectric resonator by contacting the surface of the high melting point metal film of the piezoelectric resonator.

[0007]

With the above structure, A provided on the surface of the piezoelectric substrate
Since the g-electrode contacts the Ag film of the metal terminal through the metal film having a high melting point, direct contact between the Ag electrode and the Ag film is lost, and Ag self-fusion is prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a piezoelectric resonator according to the present invention and a piezoelectric component using the piezoelectric resonator will be described below with reference to the accompanying drawings. As shown in FIG. 1, the piezoelectric resonator 1
Is composed of a piezoelectric substrate 2, a vibrating electrode 3 provided on the entire front and back surfaces of the piezoelectric substrate 2, and a high melting point metal film 4 provided on the surface of the vibrating electrode 3. The piezoelectric substrate 2 is P
It is made of a ceramic such as ZT, a crystal, or a single crystal such as LiTaO ₃ . The vibrating electrode 3 is formed by means such as Ag sputtering, vapor deposition, or print drying.

The high melting point metal film 4 is made of a metal having a higher melting point than the vibrating electrode 3, such as Ni, Cr, W, Ti, Mo, Ni.
-Cu (monel) or the like and alloys thereof are used and are formed on the vibrating electrode 3 by means such as sputtering, vapor deposition or print drying. The thickness of the metal film 4 is set so as not to impair the characteristics of the vibrating electrode 3.
Specifically, about 1/10 or less of the film thickness of the vibrating electrode 3 or 1 μ
It is preferable to select one of m or less, whichever is smaller (for example, in the case of Ni—Cu, about 0.2 μm is preferable).

FIG. 2 shows a resonator 9 assembled using the piezoelectric resonator 1 thus obtained. This resonator 9 is KH
It operates in the z band, and the inner case 10 has metal terminals 11,
The piezoelectric resonator 1 and the metal terminal 13 are housed in an overlapping manner, the opening of the inner case 10 is closed with an inner lid 14, further covered with an outer case 15, and sealed with a sealing resin 16. The piezoelectric resonator 1 is sandwiched between the metal terminals 11 and 13 at the front and back central portions thereof and vibrates in a spreading vibration mode. The metal terminals 11 and 13 are obtained by providing an Ag film on the surface of a plate material such as phosphor bronze by means such as plating. Metal terminals 11, 13
Has a spring property and is elastically in contact with the piezoelectric resonator 1 as a contact.

In the resonator 9 having the above structure, the vibrating electrode 3 of the piezoelectric resonator 1 elastically contacts with the metal terminals 11 and 13 through the metal film 4 having a high melting point.
Does not self-melt with Ag of the metal terminals 11 and 13, and even if vibration energy generated when the piezoelectric resonator 1 resonates is applied to the contact portion between the vibrating electrode 3 and the metal terminals 11 and 13, There is no concern that a part of the electrode 3 will be peeled off from the piezoelectric substrate 2.

The piezoelectric resonator according to the present invention and the piezoelectric component using the piezoelectric resonator are not limited to those in the above embodiment, but can be variously modified within the scope of the invention. In the above-described embodiment, the case of individual production is described, but in general, in mass production, the piezoelectric resonator is manufactured in the state of the mother substrate, so that the high melting point metal film is formed on the mother substrate.

The high melting point metal film is formed on the piezoelectric substrate A.
The g electrode does not necessarily have to be formed on the entire surface of the g electrode, and may be locally formed at a portion in contact with the metal terminal.

[0014]

As is apparent from the above description, according to the present invention, since the high melting point metal film is provided on the surface of the Ag electrode of the piezoelectric resonator, the Ag electrode is formed through the high melting point metal film. , A
The g film comes into contact with the metal terminal provided on the surface.
Direct contact between the g electrode and the Ag film is prevented, and Ag does not self-bond. As a result, problems such as a part of the Ag electrode being peeled off from the piezoelectric substrate are eliminated, and the reliability of electrical connection between the Ag electrode and the metal terminal is improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a piezoelectric resonator according to the present invention.

FIG. 2 is a sectional view showing a piezoelectric component using the piezoelectric resonator shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Piezoelectric resonator 2 ... Piezoelectric substrate 3 ... Vibration electrode (Ag electrode) 4 ... High melting point metal film 9 ... Resonator (piezoelectric component) 11, 13 ... Metal terminals

Claims (3)

[Claims] 1. A piezoelectric resonator comprising: a piezoelectric substrate; an Ag electrode provided on the surface of the piezoelectric substrate; and a high melting point metal film provided on the surface of the Ag electrode. 2. The piezoelectric film according to claim 1, wherein the high-melting-point metal film has a portion on its surface that elastically contacts with a metal terminal provided with an Ag film on the surface. Resonator. 3. A piezoelectric resonator according to claim 1 or 2, and an Ag film for holding the piezoelectric resonator in contact with a high melting point metal film surface of the piezoelectric resonator, the surface being provided with an Ag film. A piezoelectric component comprising a metal terminal and