To provide a method of manufacturing a BAW resonance device can improve a mechanical quality factor of a resonator.
A recess 1b is formed by etching a scheduled region of etching start of a cavity 1a on one surface of a support substrate 1 comprising an MgO substrate (Fig.1(d)). A lower electrode 31 and a piezoelectric layer 32 made of a lead-based piezoelectric material (for example, PZT) are formed at the one surface side of the support substrate 1 (Fig.1(l)). An insulating layer 4 is formed (Fig.1(p)). An upper electrode is formed, and then an etching hole 41 is formed in the insulating layer 4 surrounding the resonator (Fig.1(v)). An etching liquid is introduced through the etching hole 41 of the insulating layer 4 and the recess 1b to etch the support substrate 1, thus forming the cavity 1a (Fig.1(w)).
HAYAZAKI YOSHIKI
YAMAUCHI NORIHIRO
SHIRAI TAKEO
MATSUSHIMA CHOMEI
Atsuo Mori
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