A thin film piezoelectric device includes a substrate (12) having via
holes (22) and a piezoelectric laminated structure (14) consisting of a
lower electrode (15), a piezoelectric film (16), and an upper electrode
(17) formed on the substrate (12) via an insulation layer (13). A
plurality of thin film piezoelectric resonators (210, 220) are formed for
the via holes (22). The piezoelectric laminated structure (14) includes
diaphragms (23) located to face the via holes (22) and a support area
other than those. The thin film piezoelectric resonators (210, 220) are
electrically connected by the lower electrode (15). When the straight
line in the substrate plane passing through the centers (1, 2) of the
diaphragms (23) of the thin film piezoelectric resonators (210, 220) has
the length D1 of the segment passing through the support area and the
distance between the centers of the diaphragms of the thin film
piezoelectric resonators (210, 220) is D0,the ratio D1/D0 is 0.1 to 0.5.
The via hole (22) is fabricated by the deep graving type reactive ion
etching method.