Method for photoetching piezoelectric film transducers on two sides of acoustic bulk wave

Abstract

The invention relates to a double-sided photolithography production method for a bulk acoustic wave piezoelectric film transducer. The steps are: 1) According to the designed electrode patterns of each layer of the bottom electrode, piezoelectric film and upper electrode, make a double-sided photolithography mask for the bottom electrode. Membrane, piezoelectric film for overlaying and upper electrode mask; 2) Form a bottom electrode metal film at both ends of the sound transmission medium; 3) Double-sided photolithography of the bottom electrode pattern on the bottom electrode metal film; 4) In the transmission Sputtering piezoelectric films on both ends of the sound medium; 5) evaporating or sputtering upper electrode films on both ends of the sound transmission medium; 6) overlaying to produce piezoelectric film patterns; 7) overlaying to produce upper electrode patterns. The invention solves the problems that mechanical masks cannot produce small-sized patterns, and the pattern production is irregular and has poor precision. The precision of the mask and the consistency of the electrode patterns can reach the micron level, and the sound transmission medium has a large size range and can It achieves high alignment accuracy at both ends within the range of 2mm to 90mm, and the alignment can be less than 5 microns.

Description

technical field [0001] The invention relates to a piezoelectric thin film transducer, which is a core component of a bulk acoustic wave microwave delay line, and specifically refers to a process for manufacturing a piezoelectric thin film transducer at both ends of a sound transmission medium. Background technique [0002] The core part of the bulk acoustic wave microwave delay line is the piezoelectric film transducer. According to different positions, piezoelectric film transducers are divided into input transducers and output transducers, both of which have exactly the same structure, located symmetrically at both ends of the sound transmission medium (crystal), and the input transducer at the input end of the sound transmission medium The transducer located at the output end of the sound transmission medium is the output transducer. [0003] According to the pattern and requirements of the electrode film of each layer of the designed transducer, make the corresponding p...

AI Technical Summary

Problems solved by technology

The graphics produced by the mechanical mask are not standardized and the precision is poor. If the graphic design size is less than 0.1mm, there will be problems in the production of the mechanical mask

At the same time, the fixing of the mask and the fixture depends on manual positioning, the positioning accuracy is poor, and the collimation accuracy of the fabricated electrode pattern is poor, resulting in the insertion loss and tertiary suppression of the bulk acoustic wave microwave delay line being out of tolerance, and the product yield is low.