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US 11,696,078 B2Granted
Robust MEMS microphone
AssigneeQUALCOMM Incorporated
InventorsCraig Core, Hamid Basaeri, Robert Littrell
Life of this patent
Estimating the term…
Abstract
A robust MEMS transducer includes a kinetic energy diverter disposed within its frontside cavity. The kinetic energy diverter blunts or diverts kinetic energy in a mass of air moving through the frontside cavity, before that kinetic energy reaches a diaphragm of the MEMS transducer. The kinetic energy diverter renders the MEMS transducer more robust and resistant to damage from such a moving mass of air.
Claims20
A MEMS transducer comprising:
- a semiconductor substrate having a top layer, and a bottom surface opposite the top layer;
- a frontside cavity extending into the substrate from the bottom surface and forming an aperture at the bottom surface;
- a transducer element having a movable diaphragm disposed at the top layer of the substrate and exposed to the aperture through the frontside cavity;
- and
- a rigid kinetic energy diverter configured to divert kinetic energy of a mass of fluid moving toward the movable diaphragm, the rigid kinetic energy diverter disposed within the frontside cavity and extending into the frontside cavity in a direction away from the movable diaphragm, the rigid kinetic energy diverter having an end exposed to the aperture and distal from the diaphragm, such that the exposed distal end is nearer to the bottom surface than it is to the diaphragm, such that the frontside cavity has a plurality of portions separated by the rigid kinetic energy diverter, each portion of the plurality of portions exposing an underside of the transducer element through the frontside cavity, wherein the rigid kinetic energy diverter is contiguous with the top layer.
2 more elements
A method of fabricating a robust MEMS transducer, comprising:
- providing a starting substrate having a top surface and a bottom surface;
- fabricating a transducer structure in or on the top surface;
- and
- fabricating a frontside cavity, the frontside cavity forming an aperture in the bottom surface of the starting substrate and extending inward from the bottom surface towards and to the transducer structure, the frontside cavity comprising a diverter structure suspended within the frontside cavity, the diverter structure having a bottom face, the bottom face being closer to the bottom surface of the starting substrate than to the transducer structure,
- such that the frontside cavity has a plurality of portions separated by the diverter structure, each portion of the plurality of portions exposing an underside of the transducer structure through the frontside cavity, wherein the starting substrate comprises a silicon substrate, and fabricating the frontside cavity comprises etching the frontside cavity into the bottom surface of the silicon substrate, the frontside cavity exposing an underside of the transducer structure, said etching leaving a portion of the silicon substrate to form the diverter structure.
2 more elements
A MEMS transducer comprising:
- a semiconductor substrate having a top layer, and a bottom surface opposite the top layer;
- a frontside cavity extending into the substrate from the bottom surface and forming an aperture at the bottom surface;
- a transducer element comprising a first diaphragm and a second diaphragm disposed at the top layer of the substrate and exposed to the aperture through the frontside cavity, and wherein the first diaphragm and the second diaphragm are separated by a bridge;
- a kinetic energy diverter coupled to the bridge, and configured to divert kinetic energy of a mass of fluid moving toward the transducer element from the aperture, the kinetic energy diverter disposed within the frontside cavity and extending into the frontside cavity in a direction away from the transducer element, the kinetic energy diverter having an end exposed to the aperture and distal from the transducer element, such that the exposed distal end is nearer to the bottom surface than it is to the transducer element.
1 more element
A MEMS transducer comprising:
- a semiconductor substrate having a top layer, and a bottom surface opposite the top layer;
- a frontside cavity extending into the substrate from the bottom surface and forming an aperture at the bottom surface;
- a transducer element having a movable diaphragm disposed at the top layer of the substrate and exposed to the aperture through the frontside cavity;
- and
- a rigid kinetic energy diverter configured to divert kinetic energy of a mass of fluid moving toward the movable diaphragm, the rigid kinetic energy diverter disposed within the frontside cavity and extending into the frontside cavity in a direction away from the movable diaphragm, the rigid kinetic energy diverter having an end exposed to the aperture and distal from the diaphragm, such that the exposed distal end is nearer to the bottom surface than it is to the diaphragm, such that the frontside cavity has a plurality of portions separated by the rigid kinetic energy diverter, each portion of the plurality of portions exposing an underside of the transducer element through the frontside cavity, wherein the exposed end of the rigid kinetic energy diverter is concave.
2 more elements
A MEMS transducer comprising:
- a semiconductor substrate having a top layer, and a bottom surface opposite the top layer;
- a frontside cavity extending into the substrate from the bottom surface and forming an aperture at the bottom surface;
- a transducer element having a movable diaphragm disposed at the top layer of the substrate and exposed to the aperture through the frontside cavity;
- a rigid kinetic energy diverter configured to divert kinetic energy of a mass of fluid moving toward the movable diaphragm, the rigid kinetic energy diverter disposed within the frontside cavity and extending into the frontside cavity in a direction away from the movable diaphragm, the rigid kinetic energy diverter having an end exposed to the aperture and distal from the diaphragm, such that the exposed distal end is nearer to the bottom surface than it is to the diaphragm, such that the frontside cavity has a plurality of portions separated by the rigid kinetic energy diverter, each portion of the plurality of portions exposing an underside of the transducer element through the frontside cavity;
- and
- a backplate forming a variable capacitor with the movable diaphragm, the backplate disposed between the frontside cavity and the movable diaphragm, and wherein the rigid kinetic energy diverter is suspended from the backplate.
3 more elements
Dependencies are inferred from the claim text.