Piezoelectric thin film resonator, piezoelectric thin film resonator filter and manufacturing method thereof

A piezoelectric thin film bulk acoustic wave resonator filter comprising:

• a substrate;
• and
• a plurality of piezoelectric thin film bulk acoustic wave resonators provided on the substrate,
• wherein at least one piezoelectric thin film bulk acoustic wave resonator includes:
• a laminated structure including a first metal electrode film formed in a vacuum, a piezoelectric thin film formed on the first metal electrode film and a second metal electrode film formed on the piezoelectric thin film, the laminated structure being formed on the substrate;
• an acoustic insulating layer formed on the substrate at a position corresponding to the laminated structure, and
• a protection film formed on the second metal electrode film wherein an interface between the protection film and the second metal electrode film has a concentration of at least one of oxygen and hydrogen that is less than 1.E+21 atoms/cc.