MEMS fabrication process with two cavities operating at different pressures
First Claim
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1. A MEMS sensor device, comprising:
- a plurality of vertically-stacked inertial transducer elements, each formed in different layer of a multi-layer semiconductor structure forming a single integrated circuit device; and
a cap device bonded to the multi-layer semiconductor structure to protect at least a first exposed inertial transducer element from ambient environmental conditions.
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Abstract
A method and apparatus are described for fabricating a high aspect ratio MEMS sensor device having multiple vertically-stacked inertial transducer elements (101B, 110D) formed in different layers of a multi-layer semiconductor structure (100) and one or more cap devices (200, 300) bonded to the multi-layer semiconductor structure (100) to protect any exposed inertial transducer element from ambient environmental conditions.
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Citations
20 Claims
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1. A MEMS sensor device, comprising:
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a plurality of vertically-stacked inertial transducer elements, each formed in different layer of a multi-layer semiconductor structure forming a single integrated circuit device; and a cap device bonded to the multi-layer semiconductor structure to protect at least a first exposed inertial transducer element from ambient environmental conditions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for fabricating a transducer comprising:
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providing a MEMS wafer structure comprising a first semiconductor substrate layer and a second semiconductor layer that is formed over the first semiconductor substrate layer and etched to form a first MEMS transducer element and surrounding frame support elements; forming a first patterned metal layer on a first surface of the second semiconductor layer to define part of a first sealing ring structure on the surrounding frame support elements; providing a first cap wafer structure comprising a second substrate layer and a second patterned metal layer formed on a first surface of the second substrate layer; placing the MEMS wafer structure on the first cap wafer structure so that the first and second patterned metal layers are aligned; bonding the MEMS wafer structure to the first cap wafer structure using a first bonding process to form a bond between the first and second patterned metal layers to thereby form the first sealing ring structure on the surrounding frame support elements to surround the first MEMS transducer element; etching the first semiconductor substrate layer with a deep reactive ion etch process to form a second MEMS transducer element and surrounding frame support elements from the first semiconductor substrate layer; providing a second cap wafer structure comprising a third substrate layer having a sensor cavity; placing the second cap wafer structure on the MEMS wafer structure so that the sensor cavity and second MEMS transducer element are aligned; and bonding the second cap wafer structure to the MEMS wafer structure using a second bonding process. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A high aspect ratio transducer, comprising:
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a first routed cap structure comprising a substrate, a plurality of first metal interconnect bond spacer structures, and a high vacuum cavity formed in the substrate to define a first inertial transducer space; a first polycrystalline semiconductor substrate structure attached to the plurality of first metal interconnect bond spacer structures and comprising a first high aspect ratio proof mass element which is aligned with the first inertial transducer space, the first polycrystalline semiconductor substrate structure comprising; a first surface on which a second patterned metallic layer is formed and bonded to the plurality of first metal interconnect bond spacer structures, and a second surface on which a plurality of spacer structures are formed to define one or more out-of-plane sensing electrode spaces; a second monocrystalline semiconductor substrate structure attached to the plurality of spacer structures and comprising a second high aspect ratio proof mass element, the second monocrystalline semiconductor substrate structure comprising; a first surface attached to one or more patterned bonding layers, and a second surface on which one or more out-of-plane sensing electrodes are formed in alignment with the one or more out-of-plane sensing electrode spaces; and a second cap structure attached to the one or more patterned bonding layers and comprising a substrate in which a cavity is formed to define a second inertial transducer space which is aligned with the second inertial transducer. - View Dependent Claims (20)
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Specification