Acoustic wave filter, communication module, and method for manufacturing the filter

A duplexer comprising filters, at least one of the filters including:

• a substrate;
• resonators that are arranged on the substrate and excite acoustic waves;
• a ground terminal on the substrate;
• interconnection lines interconnecting the resonators and connecting predetermined ends of the resonators to the ground terminal;
• and
• shield electrodes disposed so that respective ones of the shield electrodes are close to and face corresponding ones of the interconnection lines,
• wherein the shield electrodes are formed into a single shield electrode having openings, and respective ones of the openings are formed above corresponding ones of the resonators.

A communication module comprising a filter and a signal circuit connected to the filter, the filter including:

• a substrate;
• resonators that are arranged on the substrate and excite acoustic waves;
• a ground terminal on the substrate;
• interconnection lines interconnecting the resonators and connecting predetermined ends of the resonators to the ground terminal;
• and
• shield electrodes disposed so that respective ones of the shield electrodes are close to and face corresponding ones of the interconnection lines,
• wherein the shield electrodes are formed into a single shield electrode having openings, and respective ones of the openings are formed above corresponding ones of the resonators.

A method for manufacturing an acoustic wave filter, comprising:

• forming, on a substrate, resonators exciting acoustic waves and interconnection lines interconnecting the resonators;
• forming a dielectric layer so as to cover the interconnection lines;
• forming a pattern having an opening on the dielectric layer by resist;
• forming a metal layer in the opening;
• and
• removing the resist,
• the metal layer being a shield layer that is close to and face the interconnection lines through the dielectric layer.