Preparation method of high-frequency bulk acoustic wave delay line transducer and high-frequency bulk acoustic wave delay line

Abstract

The invention discloses a manufacturing method for a high-frequency bulk acoustic wave delay line energy converter and a high-frequency bulk acoustic wave delay line. When the energy converter is manufactured, bottom electrode films are deposited on the two end faces of a sound bearing medium and photoetched through an upper electrode photoetching plate to form bottom electrode patterns; piezoelectric layer films are deposited on the bottom electrodes at the two ends; upper electrode films are deposited on the piezoelectric layer films at the two ends and photoetched through a bottom electrode photoetching plate to form upper electrode patterns. The aluminum nitride piezoelectric films do not need photoetching, the manufacturing technology is simplified, damage to the bottom electrode film patterns when aluminum nitride is etched is avoided, and influence on quality of follow-up processes by residues on the erosion surface of the aluminum nitride is avoided. The manufacturing technology for the high-frequency bulk acoustic wave delay line can be optimized, the manufacturing technology for the high-frequency bulk acoustic wave delay line energy converter can be simplified, the yield of technical manufacturing of devices can be increased, and product reliability can be improved.

Description

technical field [0001] The invention relates to the improvement of a bulk acoustic wave delay line, specifically refers to a preparation method of a high-frequency bulk acoustic wave delay line transducer, and also relates to a high-frequency bulk acoustic wave delay line based on the transducer, belonging to the technical field of microacoustic thin film devices. Background technique [0002] The bulk acoustic wave delay line is mainly used for the reference calibration of the wireless altimeter, and has the characteristics of high frequency, wide band, low insertion loss, small size and high stability. It has irreplaceable advantages in microwave system signal processing, especially in microwave delayed signal processing. [0003] With the development of new electronic equipment systems, the application of higher frequency bulk acoustic wave delay lines is also required. [0004] The thin-film piezoelectric transducer is the basis of the bulk acoustic wave delay line, and...

AI Technical Summary

Problems solved by technology

[0011] 1. This structure needs to etch the piezoelectric film material, which involves a complex selective etching process for various materials, especially for high-frequency bulk acoustic wave delay lines. Since the piezoelectric film is very thin, it is easy to cause the bottom electrode to be damaged during the process. The thin film is corroded; the piezoelectric thin film is not clean or corroded, and there are impurities remaining, which will greatly deteriorate the performance index of the bulk acoustic wave delay line

[0012] 2. After the pattern forming of the piezoelectric layer is completed, the aluminum metal film of the upper electrode is directly deposited on the piezoelectric layer. The adhesion of the aluminum film on the aluminum nitride film is poor, and it is easy to fall off when the upper electrode is photolithographically formed, resulting in process preparation Yield drops, and there are hidden dangers in product reliability

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