Sealed force sensor with etch stop layer
AssigneeNextInput, Inc.
InventorsJulius Minglin Tsai, Ryan Diestelhorst, Dan Benjamin
Life of this patent
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Abstract
An example microelectromechanical system (MEMS) force sensor is described herein. The MEMS force sensor can include a sensor die configured to receive an applied force. The sensor die can include a first substrate and a second substrate, where a cavity is formed in the first substrate, and where at least a portion of the second substrate defines a deformable membrane. The MEMS force sensor can also include an etch stop layer arranged between the first substrate and the second substrate, and a sensing element arranged on a surface of the second substrate. The sensing element can be configured to convert a strain on the surface of the membrane substrate to an analog electrical signal that is proportional to the strain.
Claims27
A microelectromechanical system (MEMS) force sensor, comprising:
- a sensor die configured to receive an applied force, the sensor die comprising a first substrate and a second substrate, wherein a cavity is formed in the first substrate, and wherein at least a portion of the second substrate defines a deformable membrane;
- an etch stop layer arranged between the first substrate and the second substrate;
- a sensing element arranged on a surface of the second substrate, wherein the sensing element is configured to convert a strain on the surface of the second substrate to an analog electrical signal that is proportional to the strain;
- a protective layer arranged on the surface of the second substrate;
- and
- a conductive pad arranged on the protective layer and electrically coupled to the sensing element, wherein the protective layer at least partially covers one or more of the sensing element, the surface of the second substrate, and the conductive pad.
A method of manufacturing a microelectromechanical system (MEMS) force sensor, the method comprising:
- providing a first substrate, a second substrate, a protective layer arranged on the surface of the second substrate, a conductive pad arranged on the protective layer, and an etch stop layer, wherein:
- the etch stop layer is arranged between the first and second substrates,
- a sensing element is arranged on a surface of the second substrate, and
- the protective layer is electrically coupled to the sensing element and at least partially covers one or more of the sensing element, the surface of the second substrate, and the conductive pad;
- and
- etching the first substrate, wherein the etch process removes a portion of the first substrate to form a cavity in the first substrate.
A microelectromechanical system (MEMS) force sensor comprising:
- a sensor die configured to receive an applied force, the sensor die comprising a first substrate and a second substrate, wherein a cavity is formed in the first substrate, and wherein at least a portion of the second substrate defines a deformable membrane;
- an etch stop layer arranged between the first substrate and the second substrate, wherein an etch rate of the etch stop layer is different than an etch rate of the first substrate and wherein an etch rate ratio between the etch rate of the first substrate and the etch rate of the etch stop layer is between 50 and 150;
- and
- a sensing element arranged on a surface of the second substrate, wherein the sensing element is configured to convert a strain on the surface of the second substrate to an analog electrical signal that is proportional to the strain.
Dependencies are inferred from the claim text.