Integrated electromechanical switch and tunable capacitor and method of making the same
First Claim
1. An electromechanical device comprising:
- a substrate;
a moveable beam attached to the substrate, the moveable beam being formed from a conductive layer and at least one dielectric layer; and
a fixed beam positioned above and separated from the moveable beam by a cavity, the fixed beam being formed from a conductive layer and a dielectric mechanical support layer.
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Accused Products
Abstract
A monolithically integrated, electromechanical microwave switch, capable of handling signals from DC to millimeter-wave frequencies, and an integrated electromechanical tunable capacitor are described. Both electromechanical devices include movable beams actuated either by thermo-mechanical or by electrostatic forces. The devices are fabricated directly on finished silicon-based integrated circuit wafers, such as CMOS, BiCMOS or bipolar wafers. The movable beams are formed by selectively removing the supporting silicon underneath the thin films available in a silicon-based integrated circuit technology, which incorporates at least one polysilicon layer and two metallization layers. A cavity and a thick, low-loss metallization are used to form an electrode above the movable beam. A thick mechanical support layer is formed on regions where the cavity is located, or substrate is bulk-micro-machined, i.e., etched.
32 Citations
42 Claims
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1. An electromechanical device comprising:
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a substrate;
a moveable beam attached to the substrate, the moveable beam being formed from a conductive layer and at least one dielectric layer; and
a fixed beam positioned above and separated from the moveable beam by a cavity, the fixed beam being formed from a conductive layer and a dielectric mechanical support layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A electromechanical device comprising:
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a semiconductor substrate;
a moveable beam formed on the substrate by a standard integrated process flow from at least one conductive layer and plurality of dielectric layers;
the moveable beam being attached to the substrate at one or more points, the semiconductor substrate being selectively etched underneath the moveable beam;
a fixed beam formed directly above the moveable beam and separated from the movable beam by an air cavity, the fixed beam being formed from at least one conductive layer, plurality of dielectric layers and at least one mechanical support layer; and
an integrated circuit also formed on the substrate, the integrated circuit sensing and controlling the position of the moveable beam by controlling the voltage or current flowing to the movable beam. - View Dependent Claims (21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 39, 40, 41, 42)
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26. A method of forming an electromechanical device comprising the steps of:
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fabricating a first beam and an integrated circuit monolithically on a semiconductor substrate using standard semiconductor process flows;
patterning an air cavity above the first beam using a sacrificial material;
fabricating a second beam by performing the steps of;
depositing a first conductive material on the sacrificial material by means of sputtering or evaporation;
patterning a sacrificial mold for a second conductive layer;
electrodepositing a thick second conductive layer over the mold;
removing the sacrificial mold and an excess amount of the second conductive layer underneath the mold;
depositing and patterning a mechanical support layer on top of the device;
patterning and etching the semiconductor substrate from a backside of the substrate; and
releasing the first beam so as to be movable by removing the sacrificial material on top of the first beam.
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38. A method of forming an electromechanical device comprising the steps of:
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fabricating a moveable beam and an integrated circuit on a semiconductor substrate using standard semiconductor process flows;
patterning an air-gap above the movable beam using a sacrificial material;
fabricating a fixed beam by;
depositing a thick conductive film on the sacrificial material by means of sputtering or evaporation;
patterning the conductive film via standard photolithography; and
etching the conductive film;
depositing and patterning a mechanical support layer on top of an area covered by the device;
patterning and etching the semiconductor substrate from a backside of the substrate; and
releasing the moveable beam by removing the sacrificial layer placed on top of the moveable beam.
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Specification