Patent ID: 7596840

Claim:
A method for manufacturing a piezoelectric thin film resonator, comprising: forming a buffer layer including MgO or SrO, above a single-crystal sapphire substrate; forming a piezoelectric thin film above the buffer layer; forming a first electrode above the piezoelectric thin film; forming a protection layer above the first electrode; preparing a silicon substrate having a silicon oxide layer; bonding the silicon substrate to the single-crystal sapphire substrate having the buffer layer, the piezoelectric thin film, the first electrode and the protection layer; separating the single-crystal sapphire substrate from the piezoelectric thin film by etching the buffer layer; after separating the single-crystal sapphire substrate from the piezoelectric thin film forming a second electrode above the piezoelectric thin film; and patterning the second electrode, the piezoelectric thin film and the first electrode.