Laterally sensitive accelerometer and method for making
First Claim
Patent Images
1. A laterally sensitive accelerometer comprising:
- a substrate;
a first anchor attached to the substrate, a tether coupled to the anchor and having a portion free to move in a lateral direction over the substrate in response to acceleration, a tie-bar coupled to the movable portion of the tether, and at least one movable capacitor plate coupled to the tie bar;
a first fixed capacitor plate laterally overlapping the at least one movable capacitor and vertically spaced from the at least one movable capacitor plate; and
a second anchor attached to the substrate; and
a first vertical support coupling the first fixed capacitor plate to the second anchor, wherein the first vertical support is laterally spaced from the at least one movable capacitor plate to allow the at least one movable capacitor plate to move in a lateral direction under the first fixed capacitor plate.
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Accused Products
Abstract
A micromachined capacitor structure having a first anchor (12) attached to the substrate (24), a tether (13) coupled to the anchor (12) and having a portion free to move in a lateral direction over the substrate (24) in response to acceleration. A tie-bar (14) is coupled to the movable portion of the tether (13), and at least one movable capacitor plate (16) is coupled to the tie bar (13). A first fixed capacitor plate (16) is attached to the substrate (24) laterally overlapping and vertically spaced from the at least one movable capacitor plate (16).
34 Citations
18 Claims
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1. A laterally sensitive accelerometer comprising:
- a substrate;
a first anchor attached to the substrate, a tether coupled to the anchor and having a portion free to move in a lateral direction over the substrate in response to acceleration, a tie-bar coupled to the movable portion of the tether, and at least one movable capacitor plate coupled to the tie bar; a first fixed capacitor plate laterally overlapping the at least one movable capacitor and vertically spaced from the at least one movable capacitor plate; and a second anchor attached to the substrate; and
a first vertical support coupling the first fixed capacitor plate to the second anchor, wherein the first vertical support is laterally spaced from the at least one movable capacitor plate to allow the at least one movable capacitor plate to move in a lateral direction under the first fixed capacitor plate. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- a substrate;
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8. A laterally sensitive accelerometer comprising:
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a substrate; a first set of anchors attached to the substrate; a tether spanning between two of the first set of anchors; a first tie-bar having one end coupled to a central portion of the tether; a second tie-bar having one end coupled to the central portion of the tie-bar and spaced from the first tie-bar; a set of rectangular movable capacitor plates, wherein each of the movable capacitor plates has one end attached to the first tie bar and another end attached to the second tie bar in a parallel arrangement; a second set of anchors attached to the substrate; a first set of vertical supports attached to the second set of anchors and extending upwards therefrom; and a first set of fixed capacitor plates, each of the first set of fixed capacitor plates laterally overlapping a portion of one of the movable capacitor plates and attached to at least two of the first set of vertical supports, wherein each of the first set of fixed capacitor plates is substantially parallel to the movable capacitor plates and vertically spaced from the movable capacitor plates. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A method for making a laterally sensitive accelerometer comprising the steps of:
- providing a substrate;
covering the substrate with a first sacrificial layer;
patterning the first sacrificial layer to expose portions of the substrate;
depositing a first polysilicon layer;
patterning the first polysilicon layer to provide a plurality of anchors, a tether coupled between two of the plurality of anchors, and a movable capacitor plate, wherein the movable capacitor plate is coupled to a central portion of the tether;
covering the movable capacitor plate with a second sacrificial dielectric;
patterning the second sacrificial dielectric to expose some of the anchors;
forming a first fixed capacitor plate having a first portion that is attached to at least two of the exposed anchors and a second portion that overhangs the movable capacitor plate and is vertically separated from the movable capacitor plate by the thickness of the second sacrificial dielectric; and
removing the first and second sacrificial layers by etching. - View Dependent Claims (17)
- providing a substrate;
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18. A method for making a laterally sensitive accelerometer comprising the steps of:
- providing a substrate having a surface;
forming a first fixed capacitor plate on the surface of the substrate;
covering the first fixed capacitor plate with a sacrificial layer;
patterning the sacrificial layer to expose portions of the substrate;
depositing a first polysilicon layer;
patterning the first polysilicon layer to provide a plurality of anchors, a tether coupled between two of the plurality of anchors, and a movable capacitor plate, wherein the movable capacitor plate is coupled to a central portion of the tether, has a portion of that overhangs the fixed capacitor plate and is vertically separated from the fixed capacitor plate by the thickness of the sacrificial dielectric; and
removing the sacrificial layer by etching.
- providing a substrate having a surface;
Specification