Method for manufacturing capacitive micromachined ultrasonic transducer and apparatus configured to obtain subject information using the capacitive micromachined ultrasonic transducer

A method for manufacturing a capacitive micromachined ultrasonic transducer having a vibrating membrane, a substrate, and a vibrating-membrane-supporting member configured to support the vibrating membrane to form a cavity between the substrate and the vibrating membrane, comprising steps of:

• forming a first insulating layer on either side of the substrate, the first insulating layer patterned to serve as the vibrating-membrane-supporting member;
• overlaying the vibrating membrane on the patterned first insulating layer;
• bonding the first insulating layer and the vibrating membrane by heat treatment after overlaying the vibrating membrane on the patterned first insulating layer;
• and
• forming a second insulating layer on a surface of the substrate or the vibrating membrane exposed to the cavity by introducing a gas into the cavity through a communication portion that allows the cavity to communicate with an outside of the capacitive micromachined ultrasonic transducer and subsequent thermal oxidation in an atmosphere containing the gas, after overlaying the vibrating membrane on the patterned first insulating layer, wherein
• with the cavity communicating with the outside of the capacitive micromachined ultrasonic transducer through the communication portion, the first insulating layer and the vibrating membrane are bonded by heat treatment and the second insulating layer is formed by thermal oxidation in a single heating step.