High-temperature surface acoustic wave device chip adopting array hole extraction electrode and manufacturing method of the high-temperature surface acoustic wave device chip

Abstract

The invention relates to a high-temperature surface acoustic wave device chip adopting an array hole extraction electrode and a manufacturing method of the high-temperature surface acoustic wave device chip. A channel I is arranged between a bottom electrode and a top metal, and a channel II is arranged between an upper electrode and the top metal, thereby sharing risks by using the number advantage of array holes, and greatly improving the electrical reliability of the device chip; in addition, the array holes are designed to be round holes, so that the problem that photoresist generated by square holes is not completely removed is solved; a step hole design is adopted in the channel I to isolate a piezoelectric film from metal deposited on the side wall of the hole, and an electric field generated between the upper electrode and the metal on the side wall of the hole is avoided; the high temperature resistance is improved by taking SiC as a substrate material, the insertion loss of a device is effectively reduced by taking Cu as an upper electrode material, physical or chemical separation is carried out on each chip on a wafer while a bottom electrode window is formed when the piezoelectric film is etched, and the condition that the piezoelectric film is damaged due to overlarge mechanical force in the scribing process is avoided.

Description

technical field [0001] The invention belongs to the technical field of semiconductor design and manufacture, and in particular relates to a high-temperature surface acoustic wave device chip and a manufacturing method thereof using array hole lead-out electrodes. Background technique [0002] The bottom electrode of the surface acoustic wave device has two configurations: grounded and floating. The electrode configuration will affect the electric field distribution in the piezoelectric film. The configuration of the grounded bottom surface needs to etch the piezoelectric film and the isolation layer, and open holes to connect the bottom electrode to the top metal; the configuration of the floating bottom surface does not need to open holes. The isolation layer not only isolates the top metal from the piezoelectric film, but also protects the piezoelectric film and the upper electrode (including interdigital transducers and reflection grids) from dust, impurities and corrosiv...

AI Technical Summary

Problems solved by technology

Chinese patent CN201710812303.7 provides a surface acoustic wave high-temperature pressure sensor chip based on SOI and piezoelectric film and its preparation method. The sensor chip uses a single-hole lead-out electrode, which has a high risk of electrical disconnection, and the hole shape is a square hole. The disadvantage of the square hole is that it is not easy to remove the photoresist at the edges and corners. The photoresist is non-conductive and will affect the conductivity of the circuit; in addition, the metal deposited on the side wall of the hole is in direct contact with the piezoelectric film, which will change the thickness of the piezoelectric film. Electric field distribution; traditional high-temperature MEMS devices generally use Si substrates or SOI substrates. When Si is at an ambient temperature > 200°C, the semiconductor performance will decrease and fail, and the ambient temperature > 600°C will cause mechanical properties to decrease and fail; traditional MEMS devices generally use Au, Al, Mo, Nb, Pt, W, Ti, etc. are used as upper electrode materials. These materials have the characteristics of high resistivity, resulting in large insertion loss of the device.

Images