Transducer and method for manufacturing same
A vibrating film has, at a portion of an outer peripheral edge of the vibrating film, a connection portion connected to a supporting body, a cantilever is formed that includes the vibrating film and a portion of a piezoelectric element disposed on the vibrating film and has a fixed end and a free end, an internal wiring with one end portion side being electrically connected to the piezoelectric element and having, at another end portion side, a pad portion for external wiring connection on a supporting body outside the vibrating film and a protective substrate having a wall portion formed such as to surround the cantilever and being fixed to the supporting body are further included, the wall portion has, at a location corresponding to a length intermediate portion of the connection portion, a cutout portion in which the wall portion is not present, and the pad portion is disposed at the cutout portion side with respect to the connection portion.
1 . A transducer comprising:
a supporting body that has a cavity;
a vibrating film that is provided facing the cavity and capable of vibrating in the facing direction; and
a piezoelectric element at least a portion of which is formed on a front surface of the vibrating film at an opposite side to the cavity; and
wherein the vibrating film has, at a portion of an outer peripheral edge of the vibrating film, a connection portion connected to the supporting body;
a cantilever is formed that includes the vibrating film and a portion of the piezoelectric element disposed on the vibrating film and has a fixed end and a free end;
an internal wiring with one end portion side being electrically connected to the piezoelectric element and having, at another end portion side, a pad portion for external wiring connection on the supporting body outside the vibrating film and
a protective substrate having a wall portion formed such as to surround the cantilever and being fixed to the supporting body are further included,
the wall portion has, at a location corresponding to a length intermediate portion of the connection portion, a cutout portion in which the wall portion is not present, and
the pad portion is disposed at the cutout portion side with respect to the connection portion.
2 . The transducer according to claim 1 , wherein the piezoelectric element includes a lower electrode at least a portion of which is disposed on the vibrating film, a piezoelectric film that is formed on the lower electrode, and an upper electrode that is formed on the piezoelectric film and
the internal wiring includes
an upper wiring that is disposed such as to straddle the length intermediate portion of the connection portion, has one end portion side electrically connected to the upper electrode on the vibrating film, and has a first pad portion for external wiring connection on the supporting body outside the vibrating film and
a lower wiring that has one end portion side electrically connected to the lower electrode and has a second pad portion for external wiring connection on the supporting body outside the vibrating film.
3 . The transducer according to claim 2 , wherein the supporting body includes
a supporting substrate that has the cavity and
a frame body that is formed on the supporting substrate and formed such as to surround the cavity,
the connection portion of the vibrating film is connected to the frame body, and
a slit in communication with the cavity is formed between the frame body and an outer peripheral edge of the vibrating film excluding the connection portion.
4 . The transducer according to claim 3 , comprising: a hydrogen barrier film that covers a front surface of the frame body, the front surface of the vibrating film, and a front surface of the piezoelectric element; and
an insulating interlayer film that is selectively formed on the hydrogen barrier film; and
wherein the upper wiring is formed on the insulating interlayer film, the one end portion side of the upper wiring penetrates through a laminated film of the hydrogen barrier film and the insulating interlayer film and is electrically connected to the upper electrode,
the lower wiring is formed on the insulating interlayer film, and the one end portion side of the lower wiring penetrates through the laminated film of the hydrogen barrier film and the insulating interlayer film and is electrically connected to the lower electrode.
5 . The transducer according to claim 4 , comprising: a passivation film that is formed on the insulating interlayer film and covers the upper wiring and the lower wiring.
6 . The transducer according to claim 2 , wherein a resin that is embedded in the cutout portion.
7 . The transducer according to claim 2 , wherein the protective substrate has an eave-shaped portion that is disposed along the cutout portion at a portion further to the vibrating film side than the cutout portion.
8 . A method for manufacturing a transducer comprising:
a step of forming a piezoelectric element on a vibrating film formation layer that is formed on a supporting substrate;
a step of forming a slit penetrating through the vibrating film formation layer in a thickness direction to form, in the vibrating film formation layer, a vibrating film and a frame body that surrounds the vibrating film and with which a portion is connected to a portion of an outer peripheral edge of the vibrating film;
a step of forming an internal wiring with one end portion side being electrically connected to the piezoelectric element and having, at another end portion side, a pad portion for external wiring connection on the frame body; and
a step of etching the supporting substrate from a cavity formation planned region of a front surface of the supporting substrate at an opposite side to the vibrating film formation layer to form, in a region facing the vibrating film, a cavity that is in communication with the slit; and
wherein a cantilever that includes the vibrating film and a portion of the piezoelectric element disposed on the vibrating film and has a fixed end and a free end is formed by the step of forming the cavity,
a step of fixing, to the supporting body, a protective substrate having a wall portion formed such as to surround the cantilever is further included,
the wall portion has, at a location corresponding to a length intermediate portion of the connection portion, a cutout portion in which the wall portion is not present, and the pad portion is disposed at the cutout portion side with respect to the connection portion.