| 摘要 |
PROBLEM TO BE SOLVED: To provide a super-thin plate piezoelectric device capable of facilitating electrode film thickness control, attaining the conduction with an external connection terminal by bonding, and preventing the degradation in the CI (crystal impedance) value and the generation of unwanted spurious result. SOLUTION: A recessed portion 2 is formed on one surface of a crystal substrate 1 by etching or machining, and a thin-wall portion at the bottom of the portion 2 is used as a vibration portion 3. On a flat side main surface of the substrate 1, a main electrode 5 on the approximate center portion where the portion 3 is positioned, a lead electrode 6 extending from the electrode 5 and a pad electrode 7 connected to the electrode 6 are formed with a film thickness of 50 nm being a desired electrode film thickness. Meanwhile, an electrode 10 having the predetermined film thickness difference from the main electrode 5 for excitation is formed on the whole surface of the recessed portion side main surface, a through hole 11 having the same position and the same dimension as those of the main electrode 5 for excitation is formed on the electrode 10, and then, an overall surface electrode 12 is formed on the recessed portion side main surface of the substrate 1. COPYRIGHT: (C)2004,JPO
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