The invention belongs to the technical field of MEMS loudspeakers, and particularly relates to a preparation method of a PZT
loudspeaker based on a back guide structure. Comprising the steps that a bottom
electrode metal film and a PZT piezoelectric film are sequentially sputtered on the front face of a device at high temperature through a magnetron
sputtering PVD technology; performing a bottom
electrode layer structure photoetching process; performing a top
electrode layer photoetching process; performing an upper and lower electrode
isolation layer photoetching process, performing a front surface back guide hole structure photoetching process, and
etching a top
silicon layer of the
SOI substrate material sheet through ICP (
Inductively Coupled Plasma) to form a device back guide hole structure; depositing a
Parylene protection material on the front side by a vacuum vapor
deposition process; and performing a back photoetching process, and
etching the back of the
SOI substrate material sheet through ICP (
Inductively Coupled Plasma) to form a device diaphragm cavity structure. According to the invention, the air circulation resistance of the rear cavity can be accurately controlled, the quality-spring property of the diaphragm can be matched, the rigidity and damping of the diaphragm can be balanced, the
resonance peak can be effectively reduced, the low-
frequency response bandwidth can be expanded, and the SPL can be improved.