A micro-electro-mechanical transducer (such as a cMUT) that has a movable mechanical part to transform energy. The transducer (511) has a substrate (501), a top plate (540), and a resilient structure (520) therebetween. The resilient structure has multiple connectors (530) distributed over the device element area to vertically transport the top player with distributed support not limited to edges. The resilient structure (520) may be cantilevers, or cantilever-containing structures such as bridges or crossbars, formed using a middle spring layer coveting cavities on the substrate. Connectors (530) define a transducing space below the top plate (540). The resilient structure (520) such as cantilevers enable a vertical displacement of the connectors, which transports the top plate (540) in a piston-like motion to change the transducing space and to effectuate energy transformation. No separate cells are necessary for each addressable transducer element. Multiple device elements can be made on the same substrate.

Micro-Electro-Mechanical Transducers

A method for fabricating a micro-electro-mechanical device (such as a cMUT) is disclosed. The method combines a subst (201), a middle spring layer (220) and a top plate (240) using wafer bonding technology or sacrificial technology. A cavity (202) is formed on either the top of the substrate or the bottom of the middle spring layer. A connector (230) is formed on either the top of t middle spring layer or the bottom of the top plate. Upon joining the three layers, the connector defines a transducing space between top plate and the middle spring layer. The connector is horizontally distanced from the sidewall to define a cantilever anchored at th sidewall. The cantilever and the cavity allow a vertical displacement of the connector, which transports the top wafer in a piston-like motion to change the transducing space. Multiple device elements can be made on the same substrate.

Methods for fabricating micro-electro-mechanical devices

A through-wafer interconnect and a method for fabricating the same are disclosed. The method starts with a conductive wafer to form a patterned trench by removing material of the conductive wafer. The patterned trench extends in depth from the front side to the backside of the wafer, and has an annular opening generally dividing the conductive wafer into an inner portion and an outer portion whereby the inner portion of the conductive wafer is insulated from the outer portion and serves as a through-wafer conductor. A dielectric material is formed or added into the patterned trench mechanical to support and electrically insulate the through-wafer conductor. Multiple conductors can be formed in an array.

Through-wafer interconnection

A micro-electro-mechanical transducer (such as a cMUT) having two electrodes 810, 840 separated by an insulator 830 with an insulation extension 840 is disclosed The two electrodes 810, 840 define a transducing gap therebetween The insulator has an insulating support disposed generally between the two electrodes 810, 840 and an insulation extension 830 extending into at least one of two electrodes 810 to increase the effective insulation without having to increase the transducing gap Methods for fabricating the micro-electro-mechanical transducer are also disclosed The methods may be used in both conventional membrane-based cMUTs and cMUTs having embedded springs transporting a rigid top plate.

Micro-Electro-Mechanical Transducer Having an Insulation Extension

A micro-electro-mechanical transducer (such as a cMUT) is disclosed. The transducer has a substrate, a top plate, and a middle spring layer therebetween. The substrate and the middle spring layer define cavities therebetween sidewalled by standing features. The middle spring layer is anchored by the standing features to create cantilevers over the cavities to enable a vertical displacement of connectors placed on the middle spring layer. The connectors define a transducing space between the middle spring layer and the top plate. The top plate is transported by the vertical displacement of the connectors in a piston-like motion to change the transducing space and to effectuate energy transformation. Various configurations of cantilevers, including single cantilevers, back-to-back double cantilevers and head-to-head double cantilevers (bridges) are possible.

Middle spring supported micro-electro-mechanical transducers

We have proposed an electrostatic digital micromirror utilizing interdigitated cantilevers. The electrostatically-actuated microstructure has been fabricated by the electroplated-nickel surface micromachining. Thanks to the unique design of the interdigitated cantilevers, the micromirror has an operational mechanism of a seesaw allowing accurate, reliable control of the final rotating angle. The fabricated digital micromirror has shown the rotating angle of /spl plusmn/9 degrees with an actuation voltage of 60 V.

Ji-hyuk Kim

Papers

Electrostatic digital micromirror using interdigitated cantilevers