JPH0514099A - Manufacture of surface acoustic wave device - Google Patents

Abstract

PURPOSE:To effectively suppress a re-reflection of an undesired surface acoustic wave by cutting a large sized piezoelectric substrate base material into a piezoelectric substrate with a blade whose both major sides are drawn. CONSTITUTION:In the case of manufacturing the surface acoustic wave device in which a transmission electrode and a reception electrode are formed to the surface of a piezoelectric substrate whose both ends in the direction of propagation of a surface acoustic wave are chamferred, at first a large sized piezoelectric substrate base material 10 is prepared from which plural piezoelectric substrates 1 can be extracted. Then a transmission electrode 2, a reception electrode 3, absorbing members 4a, 4b are formed corresponding to each surface acoustic wave device and the large sized piezoelectric substrate base material 10 is cut off in response to the shape of each surface acoustic wave device. Concretely, the large sized piezoelectric substrate base material 10 is adhered to a reference face 20 of a cutter via an adhesive resin sheet 21 and the material 10 is cut off by using a blade 23 whose major sides are drawn. Thus, the re- reflection of an undesired surface acoustic wave is effectively suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a surface acoustic wave device such as a surface acoustic wave filter.

[0002]

2. Description of the Related Art Conventionally, a surface acoustic wave device has been widely used as a device for extracting first and second intermediate frequencies of a communication device or an audio / video device or for extracting a video signal.

The surface acoustic wave device is, as shown in FIG.
The transmission electrode 2 and the reception electrode 3 are formed on the piezoelectric substrate 1,
Further, absorbing members 4a and 4b that absorb unnecessary surface acoustic waves are formed at both ends in the propagation direction of the surface acoustic waves.
(JP-A-2-2504) Surface acoustic waves on the piezoelectric substrate 1 are propagated from the transmitting electrode 2 to the receiving electrode 3, but unnecessary surface acoustic waves and bulk waves are generated other than during the period. In particular, unnecessary surface acoustic waves are re-reflected at the ends of the piezoelectric substrate 1 and adversely affect the regular surface acoustic waves between the transmitting electrode 2 and the receiving electrode 3. For this reason, in particular, both ends of the piezoelectric substrate 1 are coated with absorbing members 4a and 4b having a shape having a high efficiency of absorbing unnecessary surface acoustic waves, for example, silicone rubber or epoxy resin. However, there is not enough effect to absorb unnecessary surface acoustic waves that are re-reflected at the end of the substrate 1,
Both ends of the substrate 1 in the propagation direction of surface acoustic waves were chamfered.

[0004]

However, the above chamfering process is
After cutting the piezoelectric substrate base material from which a plurality of piezoelectric substrates 1 can be extracted, the end portions of the individual piezoelectric substrates 1 must be chamfered, which significantly reduces the mass productivity as the number of processing steps increases. there were.

The present invention has been devised in view of the above-mentioned problems, and an object thereof is a surface elasticity capable of effectively suppressing unnecessary re-reflection of surface acoustic waves without adding a manufacturing process. It is to provide a method of manufacturing a wave device.

[0006]

According to the present invention, there is provided a surface acoustic wave device in which a transmitting electrode and a receiving electrode are formed on the surface of a piezoelectric substrate having chamfered ends in the surface acoustic wave propagation direction. In the manufacturing method, a method for manufacturing a surface acoustic wave device is characterized in that it includes a step of cutting the large-sized base material with a blade whose both main surfaces are narrowed down.

[0007]

According to the present invention, when cutting from the large-sized base material of the piezoelectric substrate, the cutting portion corresponding to the end face of the piezoelectric substrate is cut by the blade whose both main surfaces are narrowed with a constant curvature. In this state, the end surface of the piezoelectric substrate is already the R surface. As a result, re-reflection of unnecessary surface acoustic waves can be effectively suppressed, and no special chamfering process is required, so that the mass productivity of manufacturing is significantly improved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is an external perspective view of a surface acoustic wave device manufactured according to the present invention.

Reference numeral 1 is a piezoelectric substrate, and 2 is a piezoelectric substrate 1.
The transmitting electrodes 3 formed above are receiving electrodes 4a and 4b are absorbing members for absorbing unnecessary surface acoustic waves at both ends in the propagation direction of the surface acoustic waves.

The piezoelectric substrate 1 is composed of a single crystal of lithium niobate, lithium tantalate, α-quartz or the like, or a piezoelectric ceramic of lead zirconate titanate or the like, and is sliced in a predetermined crystal orientation or in a predetermined polarization direction. It is polarized and cut, for example, width 1.1mm, length 8.5m
It has a rectangular shape of m and a thickness of 0.45 mm.

Further, both ends of the piezoelectric substrate 1 in the surface acoustic wave propagation direction are chamfered 1a and 1b so that their ridge lines are R-shaped.

The transmitting electrode 2 and the receiving electrode 3 are comb-teeth electrodes made of aluminum or the like, and their intervals are appropriately set according to the excitation frequency of the surface acoustic wave. Also, the transmission electrode 2
Is a weighted electrode structure, and the receiving electrode 3 is a normal type electrode. Specifically, a metal film such as aluminum is formed on the piezoelectric substrate 1 by a thin film technique, and then an electrode having a predetermined shape is formed by using a photolithography technique.

The absorbing members 4a and 4b are made of silicone rubber, epoxy resin or the like, and are formed at both ends of the substrate 1 in the propagation direction. Specifically, it is applied by a thick film printing method or the like so as to surround the R surface processing 1a and 1b portions of the substrate 1 and a part of the electrodes.

The surface acoustic wave device having the above structure is manufactured by the following steps.

In the first step, first, a large piezoelectric substrate base material from which a plurality of piezoelectric substrates 1 can be extracted is prepared.

In the next step, the transmitting electrode 2, the receiving electrode 3, the absorbing members 4a, 4 are arranged so as to correspond to the surface acoustic wave devices.
b is formed by the method described above.

In the next step, a large piezoelectric substrate base material 10 is used.
Is cut according to the shape of each surface acoustic wave device. Specifically, as shown in FIG. 2, it is adhesively fixed to the reference surface 20 of the cutting device via the adhesive resin sheet 21, and is cut by the blade 23. At this time, the cut portion (not shown in FIG. 2) parallel to the propagation direction of the surface acoustic wave is formed by a normal blade having a flat tip at the tip of the chip. The cutting portion 22 in the (orthogonal direction) is formed by a rotating blade 23.

FIG. 3 is an external perspective view of the blade 23.
FIG. 4 is a sectional view showing the tip shape. Blade 23
Has a disk shape, and both main surfaces at its tip have a surface (reverse R) 24 narrowed down with a constant curvature. Further, diamond particles having a predetermined particle size are attached to the cut portion.
Here, the narrowing depth a of the reverse R surface 24 is set to at least about the thickness of the piezoelectric substrate 1, and is 0.40 to 0.
It is 45 mm.

The piezoelectric substrate base material 1 is run by rotating such a blade 23 in the front-back direction of the paper surface of FIG.
The cut portion 22 is formed at 0.

As a result, the end face in the propagation direction of the piezoelectric substrate 1 cut by the cutting portion 22 is the reverse R of the blade 23.
The R surface processing 1a, 1b is performed corresponding to the surface 24. In addition, in FIG. 2, the dotted line indicates the next blade 2.
The part cut by the scan of 3 is shown.

In the next step, the piezoelectric substrate 1 is peeled off from the resin sheet 21 to achieve each surface acoustic wave device. The absorbing members 4a and 4b may be applied after being separated into individual surface acoustic wave devices, or may be applied immediately before being separated from the resin sheet 21.

According to the above manufacturing method, the cut portions 22 corresponding to both ends of the piezoelectric substrate 1 in the surface acoustic wave propagation direction are formed,
(Reverse R) surface 24 where both main surfaces at the tip are narrowed down with a constant curvature
Since it is formed by the blade 23 having the above-mentioned shape, the end faces of the piezoelectric substrate 1 are already R-face processed 1a and 1b when cut. Therefore, R chamfering is easily achieved at the end portion of the piezoelectric substrate 1 in the surface acoustic wave propagation direction without adding a special chamfering step.

The surface acoustic wave device manufactured by the above-described manufacturing method can effectively suppress unnecessary surface acoustic waves that adversely affect the surface acoustic wave propagating from the transmitting electrode 2 to the receiving electrode 3, and the absorbing member 4a. The space of 4b can be reduced, the element can be miniaturized, a large number can be obtained, and the cost can be reduced.

[0025]

According to the present invention, a surface acoustic wave device capable of effectively suppressing unnecessary re-reflection of surface acoustic waves can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a perspective view of a surface acoustic wave device.

FIG. 2 is a cross-sectional view showing a state where a cut portion is formed by the manufacturing method of the present invention.

FIG. 3 is a perspective view of a blade used in the manufacturing method of the present invention.

FIG. 4 is a partially enlarged view of a blade.

[Explanation of symbols]

 1 --- Piezoelectric substrate 10 --- Piezoelectric substrate base material 2 --- Transmission electrode 3 --- Reception electrodes 4a, 4b ... Absorption member 20・ ・ ・ Reference surface 21 ・ ・ ・ ・ ・ ・ Adhesive resin sheet 22 ・ ・ ・ ・ ・ Cutting part 23 ・ ・ ・ ・ ・ ・ Blade

Claims (1)

Claim: What is claimed is: 1. When manufacturing a surface acoustic wave device comprising a transmitting electrode and a receiving electrode formed on a surface of a piezoelectric substrate whose ends are chamfered in the surface acoustic wave propagation direction, A method for manufacturing a surface acoustic wave device, comprising: cutting a large base material with a blade whose both main surfaces are narrowed.