Capacitive micromachined ultrasonic transducer and method of fabricating the same
A capacitive micromachined ultrasonic transducer includes a device substrate including a first trench confining a plurality of first parts corresponding to a plurality of elements and a second trench confining a second part separated from the plurality of first parts, a supporting unit provided on the device substrate for confining a plurality of cavities corresponding to each of the plurality of elements, a membrane provided on the supporting unit to cover the plurality of cavities, an upper electrode provided on the membrane and electrically connected to the second part in the second trench through a via hole passing through the membrane and the supporting unit, and a through-silicon via (TSV) substrate provided on a lower surface of the device substrate, and including a plurality of first via metals connected to the plurality of first parts and a second via metal connected to the second part.
1. A capacitive micromachined ultrasonic transducer comprising:
a device substrate comprising (i) a first trench confining a plurality of first parts corresponding to a plurality of elements, and (ii) a second trench confining a second part separated from the plurality of first parts;
a supporting unit provided on the device substrate for confining a plurality of cavities corresponding to each of the plurality of elements;
a membrane provided on the supporting unit to cover the plurality of cavities;
an upper electrode provided on the membrane and electrically connected to the second part in the second trench of the device substrate through a via hole passing through the membrane and the supporting unit; and
a through-silicon via (TSV) substrate provided on a lower surface of the device substrate, the TSV substrate comprising a plurality of first via metals connected to the plurality of first parts in the device substrate and a second via metal connected to the second part in the device substrate.
2. The capacitive micromachined ultrasonic transducer of claim 1 , wherein the first trench is grid-shaped.
3. The capacitive micromachined ultrasonic transducer of claim 1 , wherein the device substrate comprises a conductive silicon substrate.
4. The capacitive micromachined ultrasonic transducer of claim 3 , wherein the device substrate has a thickness from 10 μm to 50 μm.
5. The capacitive micromachined ultrasonic transducer of claim 4 , wherein the first trench and the second trench have a same first width.
6. The capacitive micromachined ultrasonic transducer of claim 5 , wherein the first width is from 1 μm to 10 μm.
7. The capacitive micromachined ultrasonic transducer of claim 1 , wherein the first trench and the second trench are filled with an insulating material.
8. The capacitive micromachined ultrasonic transducer of claim 1 , further comprising:
a plurality of first bonding metals provided between the plurality of first parts and the plurality of first via metals; and
a second bonding metal provided between the second part and the second via metal.
9. The capacitive micromachined ultrasonic transducer of claim 1 , further comprising an insulating layer provided between the device substrate and the supporting unit and through which the via hole penetrates so that the second part contacts the upper electrode.
10. The capacitive micromachined ultrasonic transducer of claim 1 , further comprising an insulating layer provided between the membrane and the supporting unit and through which the via hole penetrates so that the second part contacts the upper electrode.