Fabrication of capacitive micromachined ultrasonic transducers by micro-stereolithography
AssigneeKoninklijke Philips Electronics N.V.
InventorJohn Douglas Fraser
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Abstract
An ultrasonic transducer is formed by a plurality of cMUT cells, each comprising a charged diaphragm plate capacitively opposing an oppositely charged base plate. The cMUT cells can be fabricated by conventional semiconductor processes and hence integrated with ancillary transducer circuitry such as a bias charge regulator. The cMUT cells can also be fabricated by micro-stereolithography whereby the cells can be formed using a variety of polymers and other materials.
Claims20
A method for fabricating a capacitive micromachined ultrasonic transducer cell on a substrate, said cell comprising a base plate which retains a first electrical charge, a support, and a diaphragm plate which retains a second electrical charge comprising depositing materials on said substrate to build up at least one of said base plate, said support, and said diaphragm plate by micro-stereolithography.
A capacitive micromachined ultrasonic transducer cell comprising:
- a base plate which retains a first electrical charge;
- a support having a top and a bottom, said bottom being located on said base plate and;
- a diaphragm plate which retains a second electrical charge and is supported by the top of said support in a capacitive relationship with said base plate;
- wherein said base plate includes a substrate having an acoustic attenuation at an ultrasonic frequency of interest which is greater than the acoustic attenuation of silicon or glass.
A method for fabricating a micromachined ultrasonic transducer cell on a substrate comprising:
- depositing multiple layers of materials at one or more selected locations on said substrate to build up a support for a diaphragm on said substrate by micro-stereolithography;
- and
- overlaying a diaphragm over said support.
Dependencies are inferred from the claim text.