Elastic wave device and method for manufacturing the same

摘要

A method of manufacturing an elastic wave device is provided with a lamination step of forming, on a substrate (1), a plurality of elastic wave devices, each of which includes a lower electrode (2), a piezoelectric film (3), and an upper electrode (4); a measuring step for measuring the operation frequency distribution of the elastic wave devices on the substrate (1); and an adjusting step for forming an adjusting region, in which the thickness of the elastic wave device is different from the thicknesses of other portions in a resonance portion of each elastic wave device, corresponding with the distribution of the operation frequencies. The adjusting region is formed so that the size of the area of the adjusting region of the resonator portion of each elastic wave device is different in accordance with the operation frequency distribution that is measured. Thus, the frequency characteristics of the elastic wave devices are easily adjusted by a small number of steps.

主权项

1. A method of manufacturing an elastic wave device comprising:
a laminating step of forming on a substrate a plurality of the elastic wave devices, which are ladder type filters each including a serial resonator and a parallel resonator, each of the serial and parallel resonators including a lower electrode, a piezoelectric film formed over said lower electrode, and an upper electrode formed at a position facing the lower electrode through said piezoelectric film therebetween, each parallel resonator including a mass load film formed over said upper electrode, and the mass load film being absent in the serial resonators; a measuring step of measuring a distribution of operating frequencies of the plurality of elastic wave devices on said substrate, a region where said lower electrode and said upper electrode face each other through the piezoelectric film therebetween functioning as a resonance portion; and an adjusting step of forming, at said resonance portion of respective serial and parallel resonators, an adjusting region in which the thickness of said resonator differs from other portions of the resonance portion, in accordance with the distribution of said operating frequencies, wherein said adjusting region is formed in said adjusting step such that the size of the area of said adjusting region in said resonance portion varies in accordance with said measured distribution of said operating frequencies, and wherein said adjusting region is formed of an adjusting film formed on at least a portion of said upper electrode or said mass load film, the adjusting film having island-shaped patterns disposed randomly.