Ultrasonic transducer structure, ultrasonic transducer, and method of manufacturing ultrasonic transducer
An ultrasonic transducer structure, an ultrasonic transducer, and a method of manufacturing the ultrasonic transducer are provided. The ultrasonic transducer structure includes a driving wafer that includes a driving circuit; and an ultrasonic transducer wafer that is disposed on the driving wafer and includes a first wafer in which a via-hole is formed, a first insulating layer formed on the first wafer, a second wafer spaced apart from the first insulating layer, and a cavity formed between the first insulating layer and the second wafer.
1. An ultrasonic transducer comprising:
a first substrate that comprises a driving circuit;
a first insulating layer that is disposed on the first substrate;
a second substrate that is disposed on the first insulating layer and has a via-hole therein;
a support portion that is disposed above and spaced apart from the second substrate;
a thin film that is supported by the support portion and is spaced apart from the second substrate; and
a cavity between the second substrate and the thin film,
wherein the first substrate and the second substrate are directly bonded to each other with the first insulating layer therebetween.
2. The ultrasonic transducer of claim 1 , wherein the first substrate is an application-specific integrated circuit substrate.
3. The ultrasonic transducer of claim 1 , wherein the second substrate is a low-resistivity silicon substrate.
4. The ultrasonic transducer of claim 1 , wherein the third substrate is a silicon substrate.
5. The ultrasonic transducer of claim 1 , wherein the first substrate and the second substrate are bonded to each other by using eutectic bonding or polymer bonding.
6. The ultrasonic transducer of claim 1 , wherein each of the first substrate and the second substrate comprises a plurality of connecting portions, and each of the connecting portions is formed of at least one material selected from the group consisting of gold (Au), copper (Cu), stannum (SN), silver (Ag), aluminum (Al), platinum (Pt), titanium (Ti), nickel (Ni), and chromium (Cr).