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US 9,499,392 B2Granted
CMOS ultrasonic transducers and related apparatus and methods
AssigneeButterfly Network, Inc.
InventorsJonathan M. Rothberg, Keith G. Fife, Tyler S. Ralston, Gregory L. Charvat, Nevada J. Sanchez
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Abstract
CMOS Ultrasonic Transducers and processes for making such devices are described. The processes may include forming cavities on a first wafer and bonding the first wafer to a second wafer. The second wafer may be processed to form a membrane for the cavities. Electrical access to the cavities may be provided.
Claims6
A method comprising:
- depositing a first conductive layer on a silicon wafer;
- depositing a second conductive layer on the first conductive layer;
- depositing a first layer of SiO2 on the second conductive layer;
- etching at least one cavity in the first layer of SiO2, a bottom surface of the at least one cavity corresponding to the second conductive layer;
- depositing a second layer of SiO2 on the first layer of SiO2;
- planarizing the second layer of SiO2;
- bonding a second wafer comprising silicon to the silicon wafer with a fusion bond;
- thinning a backside of the second wafer distal the at least one cavity to form a membrane over the at least one cavity;
- and
- depositing a third conductive layer on the membrane.
7 more elements
Dependencies are inferred from the claim text.