A method of forming a filter device has a bonding layer formed on a substrate having at least a location for a first cavity and a location for a second cavity on a single die. A piezoelectric plate is bonded to the bonding layer and spans the first and the second cavity. Excess portions of piezoelectric plate are removed that extend a certain length past the perimeter of the first cavity and of the second cavity. Excess portions may be piezoelectric material that extends in the length and width direction past the perimeter of a cavity by more than between 2 and 25 percent of the cavity perimeter. An interdigital transducer (IDT) is on a front surface of the piezoelectric plate and having interleaved fingers over the first cavity.