Microfabricated ultrasonic transducers and related apparatus and methods
First Claim
Patent Images
1. A capacitive micromachined ultrasonic transducer (CMUT) substrate, comprising:
- a first substrate having a plurality of ultrasonic transducer cavities formed in a first thermal oxide layer, the plurality of ultrasonic transducer cavities bounded on at least one side by a flexible membrane; and
a second substrate having a second thermal oxide layer, bonded to the first thermal oxide layer, defining an oxide-to-oxide bond that seals the plurality of cavities, the plurality of ultrasonic transducer cavities having an internal pressure from about 1×
10−
3 Torr to about 1×
10−
5 Torr.
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Abstract
Micromachined ultrasonic transducers integrated with complementary metal oxide semiconductor (CMOS) substrates are described, as well as methods of fabricating such devices. Fabrication may involve two separate wafer bonding steps. Wafer bonding may be used to fabricate sealed cavities in a substrate. Wafer bonding may also be used to bond the substrate to another substrate, such as a CMOS wafer. At least the second wafer bonding may be performed at a low temperature.
201 Citations
10 Claims
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1. A capacitive micromachined ultrasonic transducer (CMUT) substrate, comprising:
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a first substrate having a plurality of ultrasonic transducer cavities formed in a first thermal oxide layer, the plurality of ultrasonic transducer cavities bounded on at least one side by a flexible membrane; and a second substrate having a second thermal oxide layer, bonded to the first thermal oxide layer, defining an oxide-to-oxide bond that seals the plurality of cavities, the plurality of ultrasonic transducer cavities having an internal pressure from about 1×
10−
3 Torr to about 1×
10−
5 Torr. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification