The invention relates to the technical field of piezoelectric single-
crystal filters, in particular to a filter based on a heterogeneous integrated piezoelectric single-
crystal thin film and a preparation method, the filter comprises a
Si substrate, a dry film, the piezoelectric single-
crystal thin film, a SiO2 layer and a Si
wafer are sequentially arranged on the
Si substrate,
metal balls are arranged on the Si
wafer, the
metal balls are connected with electrodes, and the electrodes are connected with the piezoelectric single-crystal thin film. And the
electrode passes through the Si
wafer and the SiO2 layer and is connected with the piezoelectric
single crystal film. When the filter is prepared, bonding packaging can be performed after a cavity area is etched on a dry film, a
resonance area is directly defined through a photoetching process, the influence of
etching on the strength of the piezoelectric
single crystal film is avoided, a
silicon wafer bonding technology can be combined, double-sided packaging can be realized, and
batch production is supported; in the process, only the
electrode patterning step needs to be adjusted according to the type of the filter, and then the existing MEMS
process integration is utilized, so that the preparation of the FBAR and the XBAR on the same
production line is realized, the process compatibility is good, and the problems that the existing preparation method is poor in compatibility and is difficult to realize large-scale production are solved.