An acoustic wave filter includes a substrate having voids formed therein; a first resonator disposed on one or more of the voids, and a second resonator disposed on other of the voids. A first trimming layer is provided in the first resonator, and a second trimming layer is provided in the second resonator. The second trimming layer is formed of a material having an etching rate for a given etchant different from that of the first trimming layer.