Fabrication method of a ladder filter

摘要

A ladder filter includes a series resonator (S) having a first film laminate in which an upper electrode (16) and a lower electrode (12) face each other across a piezoelectric film (14), and a first film (22) provided on the first film laminate, and a parallel resonator (P) having a second film laminate having a structure similar to that of the first film laminate, a second film (20) provided on the second film laminate, and another first film (22) identical to the first film.