Acoustic wave device and filter

Abstract

An acoustic wave device and a filter. The acoustic wave device comprises: a substrate, a lower electrode layer, a piezoelectric layer, and an upper electrode layer, which are sequentially stacked from bottom to top, where at least one air cavity is disposed in the substrate at a region corresponding to the upper electrode layer, and at least one of: a first hanging bridge is located at a portion of the upper electrode layer which connects to outside, first hanging roofs are located at an edge and an inner portion of the upper electrode layer, and at least one via hole runs through one of the first hanging roofs which is located at the inner portion of the upper electrode layer; a quantity of the at least one air cavity is greater than one; or the upper electrode layer has a recess extending along a horizontal direction.

Dependencies are inferred from the claim text.