Temperature compensation type surface acoustic wave device and manufacturing method thereof

Abstract

The invention provides a temperature compensation type surface acoustic wave device and a manufacturing method thereof. The manufacturing method comprises the following steps: providing a piezoelectric material substrate; coating a first photoresist on the piezoelectric material substrate, exposing and developing the first photoresist, and defining an IDT metal layer semi-buried gully pattern; etching the piezoelectric material substrate to form an IDT metal filling trench corresponding to the IDT metal layer semi-buried trench pattern, and removing the first photoresist; depositing metal on the etched piezoelectric material substrate to form an IDT metal layer, and enabling the IDT metal layer to fill the IDT metal filling trench and overflow the IDT metal filling trench; coating a secondphotoresist on the IDT metal layer, exposing and developing the second photoresist, and defining an IDT pattern; etching the IDT metal layer to form an IDT metal finger strip structure correspondingto the IDT pattern, and removing the second photoresist; and depositing a dielectric material on the piezoelectric material substrate and the IDT metal finger strip structure to form a dielectric layer.

Description

technical field [0001] The invention relates to the technical field of surface acoustic wave devices, in particular to a temperature-compensated surface acoustic wave device (TC-SAW) and a manufacturing method thereof. Background technique [0002] Surface acoustic wave (SAW: surface acoustic wave) devices are based on the piezoelectric effect of piezoelectric materials, electronic devices that use surface acoustic waves on the surface of piezoelectric materials to work, and use interdigital transducers formed on the surface of piezoelectric materials ( IDT: interdigital transducer) (a periodic structure of metal electrodes shaped like hands crossed) converts electrical input signals into surface acoustic waves and is a key component of today's communication devices. Surface acoustic wave devices such as surface acoustic wave filters (hereinafter sometimes referred to as SAW filters) are widely used in front-ends of signal receivers, duplexers and receiving filters. SAW fil...

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Problems solved by technology

[0017] However, in the manufacturing method disclosed in Patent Document 1, it is necessary to use CMP (Chemical Mechanical Polishing) process to polish the IDT metal layer until it is flush with the first dielectric layer. The CMP equipment is expensive, and it is easy to cause cracks. The process is cumbersome and the cost is high. , temperature drift and large shear wave spurious problems

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