JPH05121993A - Surface acoustic wave device - Google Patents

Abstract

PURPOSE:To improve the reliability by arranging a lateral finger interconnecting electrically a split finger at a position apart from a tip of adjacent split fingers having an equi-potential by a considerable distance so as to prevent a broken interdigital electrode due to electrostatic destruction in the manufacture process. CONSTITUTION:Split fingers 5 being parts of an interdigital electrode 2 are arranged with lateral fingers 4a, 4b at a position apart from the tip of split fingers 5a, 5b of equi-potential, the split fingers 5a, 5b of equi-potential are interconnected electrically by a lateral finger 4. The lateral finger 4 is arranged at a position apart from the tip of the finger 5 to a degree that the effect of static capacitance formed between the lateral fingers 4a, 4b provided to the stimulation split finger and a dummy split finger is not almost caused. Thus, even when the part between the finger 5a and the common terminal 6 is broken, since the finger 5a connects to the other finger 5b via the lateral finger 4a, the connection between the finger 5a and the common terminal 6 is maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface acoustic wave device, and more particularly to a surface acoustic wave device provided with measures for preventing disconnection of a comb-shaped electrode in a manufacturing process.

[0002]

2. Description of the Related Art A surface acoustic wave device is usually formed by arranging a comb-shaped electrode (IDT) 12, an input / output electrode 13 and the like on the main surface of a surface acoustic wave substrate 11 as shown in FIG. Has been done. Then, a plurality of split fingers (electrode fingers) 15 constituting the comb-shaped electrode 12
(FIG. 3) has a problem that it is fine and easily broken due to static electricity generated in the manufacturing process or static electricity generated by temperature change in the manufacturing process when the substrate has a strong pyroelectric property.

Therefore, the comb-shaped electrode 1 in the manufacturing process
In order to prevent disconnection of wire 2, the split fingers 15 (for example, 15
a, 15b) has a lateral finger 14 (for example, 14
A surface acoustic wave device having an electrode pattern in which adjacent split fingers (for example, 15a and 15b) are electrically connected by disposing a) is used.

[0004]

However, in the surface acoustic wave device having the above-mentioned electrode pattern, it is possible to prevent disconnection failure of the comb-shaped electrode 12 in the manufacturing process. 14a,
The capacitance formed between 14b) increases, and the capacitance is 3% compared to the conventional surface acoustic wave device without the lateral fingers.
There is a problem that the amplitude characteristics of the surface acoustic wave device change, such as the dB bandwidth becoming larger.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a surface acoustic wave device capable of preventing disconnection of a comb-shaped electrode without changing amplitude characteristics. .

[0006]

In order to achieve the above object, the surface acoustic wave device of the present invention is a surface acoustic wave device comprising a surface acoustic wave substrate on which comb electrodes are arranged. Among the split fingers forming the electrode, a lateral finger electrically connecting the split fingers is disposed at a position apart from the tips of the adjacent split fingers of the same potential.

[0007]

Operation Among the split fingers constituting the comb-teeth-shaped electrode (IDT), adjacent split fingers having the same potential are electrically connected by the lateral finger arranged at a position apart from the tip thereof, so that the manufacturing is performed. It is possible to prevent breakage of the comb-shaped electrode due to contact with foreign matter or electrostatic breakdown in the process, and since the horizontal fingers are separated from the split finger tips, the opposing split finger tips for excitation and dummy The facing length of the tips of the fingers is substantially the same as the facing length in the case where the horizontal finger is not provided, and the electrostatic capacitance does not increase, and stable amplitude characteristics can be maintained.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. As in the conventional surface acoustic wave device, the surface acoustic wave device according to the embodiment of the present invention has a comb-shaped electrode (IDT) on the main surface of the surface acoustic wave substrate 1 as shown in FIG.
2, formed by arranging the input / output electrodes 3 and the like. The split finger 5 that constitutes the inter-comb-tooth electrode 2 of the surface acoustic wave device of this embodiment is shown in FIG.
As shown in, the horizontal fingers 4 (for example, 4a and 4b) are arranged at positions apart from the tips of the adjacent split fingers 5 (for example, 5a and 5b) having the same potential. , And the split fingers (for example, 5a and 5b) of the same potential are electrically connected.

Further, the lateral fingers 4 are split to the extent that there is almost no effect of capacitance formed between the exciting split fingers and the lateral fingers (for example, 4a and 4b) provided on the dummy split fingers. It is arranged at a position away from the tip of the finger 5.

Therefore, for example, even if one split finger (for example, 5a) is disconnected from the common terminal 6, the split finger 5a is connected to the other split finger 5b through the horizontal finger 4a. , The connection between the split finger 5a and the common terminal 6 is maintained.

Further, in the surface acoustic wave device of the above-mentioned embodiment, when the opposing lengths of the tip ends of the exciting split fingers and the dummy split fingers which are opposed to each other are substantially not provided with the lateral fingers. Since it is the same as the facing length, the capacitance does not increase, and stable amplitude characteristics can be secured.

Next, as a specific example, the center frequency is 47.
Table 1 shows the results of measuring the characteristics of a surface acoustic wave filter (not shown) having a 9.5 MHz and 3 dB bandwidth of 27 MHz.

[0013]

[Table 1]

In the surface acoustic wave filter of this embodiment, the horizontal finger 4 is arranged at a position where the distance D (FIG. 1) from the tip of the split finger 5 to the horizontal finger 4 is 20 μm. In addition, Table 1 has shown the average value of the result measured about 50 samples (n = 50).

Further, Table 1 shows a conventional example 1 (FIG. 3) in which a horizontal finger is provided at the tip of an adjacent split finger having the same potential, and a conventional example 2 (not shown) in which no horizontal finger is provided. The measurement results for () are simultaneously shown.

As shown in Table 1, in the conventional example 1 in which the horizontal finger is provided at the tip of the split finger, both the frequency and the 3 dB band width fluctuate due to the increase in capacitance, The surface acoustic wave filter according to the embodiment of the present invention has almost no change in capacitance as compared with the conventional example 2 in which the horizontal fingers are not provided, and the frequency and the 3 dB bandwidth are almost the same as those of the conventional example 2. Similar measurement results were obtained.

As a result of observing the surface acoustic wave filter according to this example, it was confirmed that no wire breakage due to electrostatic breakdown occurred.

Although the surface acoustic wave filter has been described in the above embodiment, the present invention is not limited to the surface acoustic wave filter, and the surface acoustic wave is formed by arranging the comb-teeth electrodes (IDT) on the substrate. It is possible to apply to various surface acoustic wave devices using the element.

[0019]

As described above, according to the surface acoustic wave device of the present invention, among the split fingers forming the comb-shaped electrode, the split fingers are separated by a considerable distance from the tips of the adjacent split fingers of the same potential. Since the horizontal fingers for electrically connecting the fingers are arranged, it is possible to prevent disconnection of the comb-shaped electrode due to electrostatic breakdown in the manufacturing process,
It is possible to prevent an increase in capacitance due to the opposing lateral fingers, ensure stable amplitude characteristics, and improve reliability.

[Brief description of drawings]

FIG. 1 is a plan view showing a comb-shaped electrode of a surface acoustic wave device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a surface acoustic wave device according to an embodiment of the present invention.

FIG. 3 is a plan view showing a comb-shaped electrode of a conventional surface acoustic wave device.

[Explanation of symbols]

 1 Surface acoustic wave substrate 2 Comb-shaped electrodes (IDT) 4, 4a, 4b Horizontal fingers 5, 5a, 5b Split finger

Claims (1)

[Claims] 1. A surface acoustic wave device comprising a surface-acoustic-wave substrate on which comb-teeth-shaped electrodes are arranged. A surface acoustic wave device characterized in that a lateral finger for electrically connecting the split finger is disposed at a position.