Method for manufacturing device
A method for manufacturing a device including an active layer and a support substrate bonded to the active layer on one surface side, the active layer including an element, an electrode configured to drive the element, a frame portion disposed around the element, and an electrode pad disposed in the frame portion and coupled to the electrode, the method including: forming a protective film at the other surface side of the frame portion and the other surface side of the element, the protective film being resistant to an etchant and including a first opening portion formed between an outer shape of the element and the frame portion and a second opening portion formed on the electrode pad; and forming a space between the element and the support substrate by etching the support substrate with the etchant passing through the first opening portion.
1 . A method for manufacturing a vibration device in which a frame portion, an element substrate including a plurality of beam-shaped elements disposed in a cavity inside the frame portion and extending from an inside of the frame portion, a buried oxide (BOX) layer, and a support substrate are laminated in this order,
a piezoelectric drive unit is laminated on a surface of the plurality of beam-shaped elements opposite the BOX layer, and
a first electrode pad and a second electrode pad are laminated on a surface of the frame portion opposite the BOX layer, the method comprising:
forming the piezoelectric drive unit by laminating a first element electrode, a piezoelectric layer, and a second element electrode in this order on the surface of the beam-shaped elements opposite the BOX layer;
forming a protective film that is resistant to an etchant on the frame portion and on the piezoelectric drive unit of the plurality of beam-shaped elements so as to form a first opening portion between an outer shape of the plurality of beam-shaped elements and the frame portion, and to form second opening portions over the first electrode pad and the second electrode pad;
forming a space between the plurality of beam-shaped elements and the support substrate by etching the support substrate with the etchant that passes through the first opening portion; and
disposing titanium nitride on the surfaces of the first electrode pad and the second electrode pad exposed from the second opening portions,
wherein the first electrode pad is connected to the first element electrode,
the second electrode pad is connected to the second element electrode, and
adjacent elements amount the plurality of beam-shaped elements vibrate in reversed phases.
2 . The method for manufacturing a vibration device according to claim 1 , wherein
the protective film is made of silicon oxide.
3 . The method for manufacturing a vibration device according to claim 1 , wherein
the support substrate is a silicon substrate, and
the etchant is tetramethylammonium hydroxide.
4 . The method for manufacturing a vibration device according to claim 1 , further comprising:
simultaneously forming the first opening portion and the second opening portion after forming the protective film.