Surface acoustic wave element, surface acoustic wave device, surface acoustic wave duplexer, and method of manufacturing surface acoustic wave element

A method of manufacturing a surface acoustic wave duplexer comprising a surface acoustic wave element, the method comprising the steps of:

• forming an electrode film composed of monocrystal aluminum, in which at least one metal of Cu, Ta, W and Ti is segregated in the monocrystal aluminum, on a piezoelectric substrate by sputtering Al alloy;
• forming a thin film electrode by patterning the electrode film;
• forming a bump electrode;
• and
• mounting the thin film electrode and the bump electrode on a mounting substrate having an electrode terminal formed on a surface of the mounting substrate, wherein the bump electrode is disposed between the thin film electrode and the electrode terminal of the mounting substrate.

A method of manufacturing a surface acoustic wave device comprising a surface acoustic wave element, the method comprising the steps of:

• forming an electrode film composed of monocrystal aluminum, in which at least one metal of Cu, Ta, W and Ti is segregated in the monocrystal aluminum, on a piezoelectric substrate by sputtering Al alloy;
• forming a thin film electrode by patterning the electrode film;
• forming a bump electrode;
• and
• mounting the thin film electrode and the bump electrode on a mounting substrate having an electrode terminal formed on a surface of the mounting substrate, wherein the bump electrode is disposed between the thin film electrode and the electrode terminal of the mounting substrate.