Capacitance-based pressure sensor including pressure vessel(s)
AssigneeKionix, Inc.
InventorScott G. Adams
Life of this patent
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Abstract
Techniques are described herein that perform capacitance-based pressure sensing using pressure vessel(s). A pressure vessel is an object that has a cross section that defines a void. The void has a shape that is configured to change based on a change of pressure difference between a cavity pressure in a cavity in which at least a portion of the pressure vessel is suspended and a vessel pressure in the pressure vessel. The pressure vessel may be formed in the shape of an enclosed loop (e.g., along a path that is perpendicular to the cross section), resulting in a looped pressure vessel. For instance, an end of the pressure vessel may be connected to another end of the pressure vessel to form the enclosed loop.
Claims28
A pressure sensor comprising:
- a semiconductor substrate that includes a first cavity;
- a pressure vessel having a cross section that defines a void, the void having a shape that is configured to change based on a change of pressure difference between a cavity pressure in the first cavity and a vessel pressure in the pressure vessel, at least a first portion of the pressure vessel suspended in the first cavity;
- and
- a capacitive structure coupled to the first portion of the pressure vessel, the capacitive structure configured to provide a first capacitance that changes with the shape of the void.
A method comprising:
- providing a semiconductor substrate that includes a cavity;
- fabricating a pressure vessel having a cross section that defines a void, the void having a shape that is configured to change based on a change of pressure difference between a cavity pressure in the cavity and a vessel pressure in the pressure vessel, at least a portion of the pressure vessel suspended in the cavity;
- and
- fabricating a capacitive structure coupled to the portion of the pressure vessel, the capacitive structure configured to provide a capacitance that changes with the shape of the void.
A method comprising:
- embedding at least a support portion of a pressure vessel that is in a shape of an enclosed loop in a semiconductor substrate external to a cavity in the semiconductor substrate in which the pressure vessel is suspended, the pressure vessel having a cross section that defines a void, the void having a shape that is configured to change based on a change of pressure difference between a cavity pressure in the cavity and a vessel pressure in the pressure vessel, the enclosed loop having an inner perimeter and an outer perimeter;
- providing first and second metallization layers on respective inner and outer perimeters of the enclosed loop, the first metallization layer being electrically connected to a portion of the semiconductor substrate that is within the inner perimeter of the enclosed loop;
- routing a first metallization trace from the portion of the semiconductor substrate that is within the inner perimeter of the enclosed loop to a first electrode on a top surface of the semiconductor substrate that is outside an isolation barrier that surrounds the cavity;
- and
- routing a second metallization trace from the second metallization layer to a second electrode on the top surface of the semiconductor substrate that is outside the isolation barrier.
A method comprising:
- receiving a cavity pressure in a cavity that is included in a semiconductor substrate of a pressure sensor;
- receiving a vessel pressure in a pressure vessel of the pressure sensor, at least a portion of the pressure vessel being suspended in the cavity;
- and
- measuring a capacitance that changes with a shape of a void that is defined by a cross section of the pressure vessel using a capacitive structure that is coupled to the portion of the pressure vessel.
Dependencies are inferred from the claim text.