Bulk acoustic wave resonator and fabrication method therefor

A method for producing a bulk acoustic wave (BAW) resonator, comprising:

• forming a plurality of sacrificial layers and a plurality of piezoelectric layers which are alternately stacked on a substrate;
• forming a capping layer on a top sacrificial layer, and forming a hard mask on the capping layer;
• forming a plurality of first openings extending along a first direction by etching the aforementioned layers in sequence until the substrate is exposed;
• forming a first isolation layer in each opening;
• forming a plurality of second openings extending along a second direction by etching until the substrate is exposed;
• removing the plurality of sacrificial layers through the second openings, to form a plurality of first cavities between adjacent piezoelectric layers, between the piezoelectric layers and the capping layer, and between the piezoelectric layers and the substrate;
• forming a plurality of electrode layers on at least top surfaces and bottom surfaces of the piezoelectric layers through the second openings;
• and
• forming, in the first openings, electrode interconnection layers connected to electrodes at the bottom surfaces of the piezoelectric layers.