JPH088679A - Piezoelectric resonator and its production - Google Patents

Abstract

PURPOSE:To prevent a solder from flowing out to an oscillation electrode to cause undesired damping of oscillation at the time of soldering a lead terminal to a terminal electrode. CONSTITUTION:Oscillation electrodes 3 to 6, 12, and 13, terminal electrodes 7, 8, and 14, and connection lines 9 to 11, 15, and 16 which connect them are given by a first metallic film 28 formed on a piezoelectric substrate 2 and a second metallic film 29 formed on this metallic film 28, and the first metallic film 28 is made of Ni-Cu alloy or the like to which solder is difficult to stuck, and the second metallic film 29 is provided with the part where the first metallic film 28 is exposed in a part of each of connection lines 9, 10, 15, and 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric resonator used as a filter, an oscillator, a discriminator, a trap element, etc., and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 4 is of interest to the present invention.
For example, a piezoelectric resonator used as a filter or a discriminator is shown. The piezoelectric resonator 1 shown here includes a piezoelectric substrate 2 made of, for example, ceramic. In FIG. 4, (a) shows the configuration on the upper main surface side of the piezoelectric substrate 2, and (b) shows the configuration on the lower main surface side as well. The piezoelectric resonator 1 constitutes an energy trapping type resonator utilizing thickness shear vibration.

On the upper main surface of the piezoelectric substrate 2, as shown in FIG.
As shown in Figure 2, two sets of vibrating electrodes 3 and 4 and 5 and 6 separated from each other are formed. Further, terminal electrodes 7 and 8 are formed at the respective ends of the piezoelectric substrate 2. The terminal electrode 7 is connected to the vibrating electrode 3 via the connection line 9.
The terminal electrode 8 is connected to the vibrating electrode 6 via the connection line 10. The vibrating electrodes 4 and 5 are
They are connected to each other by a connection line 11.

On the other hand, on the lower main surface of the piezoelectric substrate 2, FIG.
As shown in (b), a vibrating electrode 12 commonly facing the pair of vibrating electrodes 3 and 4 and a vibrating electrode 13 commonly facing the pair of vibrating electrodes 5 and 6 are formed. In addition, a terminal electrode 14 is formed at the center of the piezoelectric substrate 2 in the longitudinal direction. Terminal electrode 14 and vibrating electrode 12
And 13 are connected to each other via connection lines 15 and 16, respectively.

Lead terminals 17 to 19 are attached to the above-described piezoelectric resonator 1 as required. More specifically, the lead terminal 17 is the terminal electrode 7, the lead terminal 18 is the terminal electrode 8, and the lead terminal 19 is the terminal electrode 14.
Are connected by solders 20, 21 and 22, respectively.

The solders 20-22 described above, when applied, tend to flow over the connecting lines 9, 10, 15 and 16 and onto the vibrating electrodes 3, 6, 12 and 13. However, these solders 20-22
On the vibrating electrodes 3, 6, 12 and 13,
The vibrations excited by the vibrating electrodes 3, 6, 12 and 13 cause undesired damping. Therefore, in such a state, a large loss is caused in the electric characteristics of the piezoelectric resonator 1 and the characteristic failure of the piezoelectric resonator 1 is caused.

In order to solve the above problems, FIG.
As shown in FIG. 5, the solder outflow preventing resin films 23, 24, 25 are provided so as to cross the connection lines 9, 10, 15 and 16.
It is described in Japanese Utility Model Laid-Open No. 2-106723 that the and 26 are formed by printing, for example.

[0008]

However, in order to form the above-mentioned resin films 23 to 26, for example, a printing process is required, resulting in an increase in the number of processes for manufacturing the piezoelectric resonator 1. .

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a piezoelectric resonator and a method for manufacturing the same, which can prevent the solder from flowing out without increasing the number of steps.

[0010]

According to the present invention, a vibrating electrode, a connection line and a terminal electrode formed on a piezoelectric substrate are
Heretofore, attention has been paid to the fact that it has a two-layer structure of a first metal film for increasing the adhesion strength with a piezoelectric substrate and a second metal film that provides good solderability and has a low electric resistance. It was done.

The piezoelectric resonator according to the present invention includes a piezoelectric substrate, a plurality of vibrating electrodes facing each other, and a plurality of terminal electrodes connected to the vibrating electrodes via connection lines. These vibrating electrodes, connection lines and terminal electrodes are provided by the first metal film formed on the piezoelectric substrate and the second metal film formed thereon, as described above. In such a piezoelectric resonator, according to the present invention, in order to solve the above-mentioned technical problem, the first metal film is made of a metal that is hard to be soldered, and the second metal film is formed in a part of each connection line. It is characterized in that it has a portion for exposing the first metal film.

Also, in the method of manufacturing a piezoelectric resonator according to the present invention, a piezoelectric substrate is prepared, a first metal film is formed on the piezoelectric substrate, and a second metal film is formed on the first metal film. And first
And patterning the second metal film to form a plurality of vibrating electrodes facing each other and a plurality of terminal electrodes connected to the vibrating electrodes via connection lines, respectively.
In order to solve the above-mentioned technical problems, the first metal film is formed of a metal that does not easily adhere to solder, and the second metal film corresponds to a part of each connection line. It is characterized in that it is formed so as to expose the first metal film.

[0013]

In the piezoelectric resonator according to the present invention, since the first metal film is exposed at a part of the connection line, the solder is prevented from flowing out at this part due to the property of the first metal film that the solder is hard to stick. It can be stopped.

Further, in the method for manufacturing a piezoelectric resonator according to the present invention, when the second metal film is formed on the first metal film made of a metal which is hard to be soldered, a region corresponding to a part of the connection line is formed. Since the first metal film is exposed in step 1, the first metal film is exposed in a part of the connection line when the vibrating electrode, the connection line and the terminal electrode are formed by the subsequent patterning.

[0015]

As described above, according to the present invention, the function of preventing solder outflow can be exerted only by exposing a part of the first metal film made of a metal to which solder is difficult to adhere from the second metal film. be able to. Therefore, when forming the second metal film, it suffices to expose the first metal film at a desired portion by using a mask or the like. Therefore, the number of steps can be reduced, and as a result, the manufacturing cost of the piezoelectric resonator can be reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view corresponding to FIG. 4, showing a piezoelectric resonator 1a according to an embodiment of the present invention. The piezoelectric resonator 1a shown in FIG. 1 includes many elements common to the piezoelectric resonator 1 shown in FIG. Therefore, in FIG. 1, the elements corresponding to the elements shown in FIG. 4 are denoted by the same reference numerals, and the duplicate description will be omitted.

The piezoelectric resonator 1a shown in FIG. 1 is preferably manufactured as follows in order to efficiently obtain a plurality of piezoelectric resonators.

First, as shown in FIG. 2A, a mother piezoelectric substrate 27 is prepared. The mother piezoelectric substrate 27 is to be cut later to provide a plurality of piezoelectric substrates 2 for the individual piezoelectric resonators 1a. The mother piezoelectric substrate 27 is made of, for example, ceramic and is polarized.
After being polished, the first metal film 28 is formed on the main surface thereof. The first metal film 28 has a function of increasing the adhesion strength with the mother piezoelectric substrate 27, preventing solder erosion, and having a property of preventing solder from sticking. To meet these demands, the first metal film 28 is made of, for example, a Ni—Cu alloy or Cr, and is formed by sputtering or the like.

Next, as shown in FIG. 2B, a second metal film 29 is formed on the first metal film 28. The second metal film 29 is made of a metal that provides good solderability and has a low electric resistance. Therefore, the second metal film 29
Is made of, for example, Ag and is formed by vacuum vapor deposition or sputtering. When forming this second metal film 29, for example, a mask is used, whereby
The first metal film 28 is exposed in a region corresponding to a part of the connection lines 9 and 10.

Next, as shown in FIG. 3, the first and second
The metal films 28 and 29 of FIG.
Patterns corresponding to the vibrating electrodes 3 to 6, the terminal electrodes 7 and 8 and the connection lines 9 to 11 shown in (a) are formed. At this stage, the first metal film 28 is exposed in the regions corresponding to a part of each of the connection lines 9 and 10. The first and second metal films 28 and 2
The patterning of 9 is achieved, for example, by forming a resist film by printing and then etching.

Although the above-described steps are for obtaining the structure shown in FIG. 1A of the piezoelectric resonator 1a to be obtained, the same process for obtaining the structure shown in FIG. This step is performed on the other main surface side (not shown) of the mother piezoelectric substrate 27.

Next, the mother piezoelectric substrate 27 is cut along a cutting line 30 shown by a chain line in FIG. As a result, a plurality of piezoelectric resonators 1a shown in FIG. 1 are obtained.

The solder electrodes 20 to 2 are respectively attached to the terminal electrodes 7, 8 and 14 of the piezoelectric resonator 1a thus obtained.
2, the lead terminals 17 to 19 are connected. Since the first metal film 28 is exposed so as to cross each of the connection lines 9, 10, 15 and 16 and the solder is hard to stick to these portions, the solders 20 to 22 are provided.
It is prevented by such a first metal film 28 that the liquid flows out to the vibrating electrodes 3, 6, 12 and 13.

The size of the exposed portion of the first metal film 28 as described above is about 0.2 mm, for example. Therefore, the lack of the second metal film 29 caused by the exposure of the first metal film 28 is not enough to cause the deterioration of the performance of the piezoelectric resonator 1a.

Although the present invention has been described above with reference to the illustrated embodiments, several other modifications are possible within the scope of the present invention.

First, the piezoelectric resonator to which the present invention is applied is not limited to the one used as the energy trapping type filter or discriminator utilizing the thickness shear vibration as described above, but other types or other uses. It may be a piezoelectric resonator. In short, the terminal electrode is connected to the vibration electrode provided in the piezoelectric resonator via the connection line,
The present invention can be advantageously applied to any piezoelectric resonator as long as the terminal electrode is soldered.

The soldering applied to the terminal electrodes as described above may be for connecting not only the lead terminals but also electric parts other than the lead terminals.

Regarding the method of manufacturing the piezoelectric resonator, the mother piezoelectric substrate 27 is prepared in the above-mentioned embodiment, but the piezoelectric substrate for each piezoelectric resonator is first prepared, and then the vibrating electrodes and terminals are prepared. Processes for forming electrodes and connection lines may be performed.

Further, the piezoelectric resonator according to the present invention can be manufactured not only by the manufacturing method described in claim 2 but also by another manufacturing method. For example, on a piezoelectric substrate,
A first metal film is formed, the first metal film is first patterned, and then a second metal film is formed by using a mask or the like so that a part of the second metal film is exposed. May be formed.

[Brief description of drawings]

1 shows a piezoelectric resonator 1a according to an embodiment of the present invention, (a) is a front view of the piezoelectric resonator 1a,
(B) is a rear view of the same.

FIG. 2 shows a mother piezoelectric substrate 27 prepared to obtain the piezoelectric resonator 1a shown in FIG. 1, (a) showing a state where a first metal film 28 is formed on the mother piezoelectric substrate 27, (b) )
Shows the state in which the second metal film 29 is formed on the first metal film 28.

FIG. 3 is a first and second metal film 2 shown in FIG. 2 (b).
FIG. 30 is a plan view of the mother piezoelectric substrate 27 showing a state after patterning 8 and 29.

FIG. 4 Conventional piezoelectric resonator 1 of interest to the present invention
And (a) is a front view and (b) is a rear view.

[Explanation of symbols]

 1a Piezoelectric resonator 2 Piezoelectric substrate 3 to 6,12,13 Vibrating electrode 7,8,14 Terminal electrode 9 to 11,15,16 Connection line 17 to 19 Lead terminal 20 to 22 Solder 27 Mother piezoelectric substrate 28 First metal Film 29 Second metal film

Claims (2)

[Claims] 1. A vibrating electrode, comprising: a piezoelectric substrate; a plurality of vibrating electrodes facing each other; and a plurality of terminal electrodes connected to the vibrating electrodes via connection lines, respectively.
In the piezoelectric resonator, the connection line and the terminal electrode are provided by a first metal film formed on the piezoelectric substrate and a second metal film formed on the first metal film. The piezoelectric resonator is characterized in that the film is made of a metal to which solder is hard to adhere, and the second metal film has a part exposing a part of the connection line to the first metal film. 2. A piezoelectric substrate is prepared, a first metal film is formed on the piezoelectric substrate, a second metal film is formed on the first metal film, and the first and second metals are formed. A method for manufacturing a piezoelectric resonator, comprising steps of patterning a film to form a plurality of vibrating electrodes facing each other and a plurality of terminal electrodes connected to these vibrating electrodes via connection lines, respectively. The first metal film is formed of a metal to which solder is hard to attach, and the second metal film is formed so as to expose the first metal film in a region corresponding to a part of each connection line. A method for manufacturing a piezoelectric resonator, comprising: