Acoustic surface wave filter and manufacturing method thereof

Abstract

An acoustic surface wave filter comprises a base (2) and a cap (9), a filter pattern layer is arranged on the base (2), and the filter pattern layer comprises a sending interdigital transducer (3), a receiving interdigital transducer (4), ground wires (7), a signal input port (5) and a signal output port (6); the ground wires (7) comprise a first ground wire (71) connected with the sending interdigital transducer (3) and a second ground wire (72) connected with the receiving interdigital transducer (4); the sending interdigital transducer (3) and the receiving interdigital transducer (4) are rectangular interdigital electrodes formed by two comb electrodes which are interdigitated; corners of common terminals of the comb electrodes of the sending interdigital transducer (3) and the receiving interdigital transducer (4) are round corners. In order to effectively avoid a point effect, corner rounding treatment is adopted at joints of the ground wires and the interdigital electrodes, and the point field intensity is effectively reduced, thereby avoiding punch-through and improving reliability of a device.

Description

technical field [0001] The invention relates to a surface acoustic wave (SAW) filter and a manufacturing method thereof, belonging to the technical field of radio frequency MEMS. Background technique [0002] Surface Acoustic Wave (SAW, SurfaceAcousticWave) is an elastic wave that is generated and propagated on the surface of a piezoelectric substrate material, and whose amplitude decreases rapidly as it goes deeper into the substrate material. With its unique advantages, such as light weight, small size and high reliability, it is widely used in many fields such as mobile communication, radio and television, non-destructive testing, identification and positioning, navigation and telemetry. For example, the dual-band SAW filter with 60MHz bandwidth applied to a 1.0GHz PCS terminal and the SAW filter for dual-mode portable mobile phones developed by Fujitsu (patent publication number JP2005210158A). However, the center frequency f of the surface acoustic wave filter made of ...

AI Technical Summary

Problems solved by technology

The interdigitated strips are too thin. In the SAW propagation project, due to the high ambient temperature, the tip effect is prone to occur, causing the interdigitated strips to break, resulting in complete damage to the SAW

Therefore, it is impossible to meet the needs of the rapid development of surface acoustic waves only by using advanced semiconductor planar technology.

In addition, the thinner the fingers are, the greater the resistance will be, which will generate greater heat energy, which will melt and break the thin fingers, completely destroying the surface acoustic wave, which is very important for the production of high-power Disadvantages of surface acoustic wave devices

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