A processing method for suppressing clutter in surface acoustic wave filter

Abstract

The present invention discloses a processing method for suppressing the clutter of a surface acoustic wave filter. An interdigitated finger transducer is manufactured on a piezoelectric substrate, and the chip is sliced ​​and cut by a V-shaped dicing knife, so that the end face of the surface acoustic wave filter chip is inclined. The blade of the V-shaped dicing knife is V-shaped, and the angle of the V-shaped blade is 5° to 70°. The V-shaped dicing knife is made of metal or resin material. The clutter generated when the interdigitated finger transducer excites the surface wave is reflected by the inclined surfaces at both ends, thereby reducing the parasitic response within the passband of the surface acoustic wave filter and ensuring the normal operation of the passband frequency response of the surface acoustic wave filter. The production process can be simplified, the area of ​​the surface acoustic wave chip can be reduced, and a surface acoustic wave filter chip with higher electrical performance can be achieved.

Description

Technical Field

[0001] The invention relates to a surface acoustic wave filter manufacturing technology in the communication field, and in particular to a processing method for suppressing clutter in the surface acoustic wave filter. Background Art

[0002] The surface acoustic wave filter is a transducer-type passive bandpass filter made by utilizing the piezoelectric effect of crystals such as lithium tantalate, lithium niobate, and quartz and the physical characteristics of surface acoustic wave propagation.

[0003] With the development of technology, there are higher requirements for the electrical performance of surface acoustic wave filters. In order to suppress the clutter response in the passband, in addition to doing enough work in design, some of the two ends of the surface acoustic wave filter chip need to be processed. The usual method is to obliquely divide the two ends of the surface acoustic wave filter chip into a parallelogram.

[0004] like Figure 1 As shown in the figure, while exciting the surface acoustic wave, it also brings unwanted clutter such as body wave and shallow body wave. When these clutter are reflected to the vertical cutting end face, they will be reflected to the receiving transducer, resulting in large passband ripple. The traditional solution is to increase the reflection angle at both ends of the chip and design the entire chip into a parallelogram.

[0005] The disadvantages of the above-mentioned prior art are that it will lead to an increase in chip area and an increase in packaging volume. Summary of the invention

[0006] The purpose of the present invention is to provide a processing method for suppressing clutter in a surface acoustic wave filter, aiming at suppressing clutter in the process of surface acoustic wave transmission.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] The processing method for suppressing clutter of a surface acoustic wave filter of the present invention manufactures an interdigitated transducer on a piezoelectric substrate, and performs dicing and cutting by a V-shaped dicing knife, so that the end face of the surface acoustic wave filter chip is inclined.

[0009] It can be seen from the technical solution provided by the present invention that the processing method for suppressing the clutter of the surface acoustic wave filter provided by the embodiment of the present invention mainly uses a V-shaped dicing knife to make the cutting surface form a certain angle with the surface acoustic wave transmission surface when cutting the chip, so that useless clutter such as body waves and shallow body waves accompanying the surface acoustic wave transmission process is reflected by the inclined end face. The production process of the surface acoustic wave filter is simplified, the processing efficiency is improved, and the chip volume is reduced. The saved space can realize a surface acoustic wave filter chip with higher electrical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of a surface acoustic wave filter after conventional wafer cutting in the prior art;

[0011] Figure 2 Schematic diagram of V-knife cutting of a surface acoustic wave filter substrate in an embodiment of the present invention.

[0012] In the figure:

[0013] 1. V-shaped dicing knife, 2. SAW filter chip interdigital transducer, 3. Piezoelectric substrate, 4. Cutting path. DETAILED DESCRIPTION

[0014] The embodiments of the present invention will be described in further detail below. The contents not described in detail in the embodiments of the present invention belong to the prior art known to those skilled in the art.

[0015] The preferred embodiment of the processing method for suppressing clutter in a surface acoustic wave filter of the present invention is as follows:

[0016] An interdigital transducer is manufactured on a piezoelectric substrate, and the chip is diced and cut by a V-shaped dicing knife to make the end face of the SAW filter chip be inclined.

[0017] The blade of the V-shaped dicing knife is V-shaped, and the angle of the V-shaped blade is 5° to 70°.

[0018] The V-shaped dicing knife is made of metal or resin material.

[0019] The interdigital transducer is made of conductive metal material, and the piezoelectric substrate is made of lithium tantalate, lithium niobate or quartz after grinding and polishing.

[0020] The clutter generated when the interdigital transducer excites the surface wave is reflected by the inclined surfaces at both ends, thereby reducing the parasitic response in the passband of the surface acoustic wave filter.

[0021] The processing method for suppressing clutter in the surface acoustic wave filter of the present invention is intended to suppress clutter in the process of surface acoustic wave transmission. According to the principle of the surface acoustic wave filter, an interdigitated transducer is made on a piezoelectric substrate. The end face of the surface acoustic wave filter chip is V-shaped by dicing with an angled cutting knife, which is conducive to the reflection and dissipation of clutter, and plays the same role as the parallelogram chip, ensuring the normal operation of the passband frequency response of the surface acoustic wave filter. The production process can be simplified and the area of ​​the surface acoustic wave chip can be reduced.

[0022] The present invention can also cut the chip end face into an inclined surface without changing the original chip size, thereby playing the same role in suppressing noise. The surface acoustic wave filter used in this method adopts a transmission-type design structure, including a wafer substrate and an interdigitated transducer. When cutting the chip, a V-shaped dicing knife is mainly used to form a certain angle between the cutting surface and the surface acoustic wave transmission surface. As a result, useless noise such as body waves and shallow body waves accompanying the surface acoustic wave transmission process are reflected by the inclined end face. The present application simplifies the production process of the surface acoustic wave filter, improves processing efficiency, and at the same time reduces the chip size. The saved space can realize a surface acoustic wave filter chip with higher electrical performance. Specific embodiment:

[0024] According to the normal semiconductor chip processing process, surface acoustic wave filter chip wafers are produced.

[0025] like Figure 2 As shown, the blade of the V-shaped dicing knife 1 has a certain angle, and when the angle is between 5° and 70°, it can effectively reflect the scattered end surface noise.

[0026] The interdigital transducer 2 is made of conductive metal material. The input transducer uses the positive piezoelectric effect to excite surface acoustic waves, and at the same time excites unwanted clutter such as body waves and shallow body waves. When the sound wave is transmitted to the output transducer, the output transducer uses the inverse piezoelectric effect to convert the sound signal into an electrical signal.

[0027] The base material of the piezoelectric substrate 3 of the surface acoustic wave filter is usually made of piezoelectric single crystal materials such as lithium tantalate, lithium niobate, and quartz through grinding and polishing.

[0028] The cutting path 4 is the groove after the dicing knife cuts, and its angle is consistent with the design angle of the dicing knife. It is used to reflect the clutter at both ends of the chip.

[0029] By slicing the wafer with an angled cutting knife, the influence of noise caused by surface acoustic wave transmission can be eliminated, while reducing the chip packaging size.

[0030] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A processing method for suppressing clutter in a surface acoustic wave filter, wherein an interdigitated transducer is manufactured on a piezoelectric substrate, characterized in that: Slice and cut using a V-shaped dicing knife to make the end surface of the SAW filter chip be inclined; The blade of the V-shaped dicing knife is V-shaped, and the angle of the V-shaped blade is 5° to 70°; The V-shaped dicing knife is made of metal or resin material; The interdigital transducer is made of conductive metal material, and the piezoelectric substrate is made of lithium tantalate, lithium niobate or quartz after grinding and polishing; The clutter generated when the interdigital transducer excites the surface wave is reflected by the inclined surfaces at both ends, thereby reducing the parasitic response in the passband of the surface acoustic wave filter.

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