Ruggedized MEMS force die
First Claim
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1. A MEMS force die, comprising:
- a protective platform for receiving an applied force; and
a force sensor having a center and an outer edge, wherein the force sensor is bonded to the protective platform at a plurality of peripheral points along at least a portion of the outer edge, the force sensor comprising a plurality of flexible sensing elements having one or more piezoresistive strain gauges formed on an upper surface of the flexible sensing elements, each of the flexible sensing elements having a thickness less than a thickness at the center of the force sensor, the flexible sensing elements being configured to deflect in response to the applied force received by the protective platform and transferred to the force sensor, and the one or more piezoresistive strain gauges providing an output signal proportional to the applied force,wherein the force sensor defines a gap at the center thereof, the gap being arranged between the protective platform and the force sensor, and a depth of the gap being configured to limit an amount of deflection of the flexible sensing elements,wherein the protective platform is above the flexible sensing elements in a thickness direction, andwherein the plurality of peripheral points are arranged over the flexible sensing elements.
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Abstract
Described herein are ruggedized wafer level MEMS force dies composed of a platform and a silicon sensor. The silicon sensor employs multiple flexible sensing elements containing Piezoresistive strain gages and wire bonds.
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Citations
18 Claims
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1. A MEMS force die, comprising:
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a protective platform for receiving an applied force; and a force sensor having a center and an outer edge, wherein the force sensor is bonded to the protective platform at a plurality of peripheral points along at least a portion of the outer edge, the force sensor comprising a plurality of flexible sensing elements having one or more piezoresistive strain gauges formed on an upper surface of the flexible sensing elements, each of the flexible sensing elements having a thickness less than a thickness at the center of the force sensor, the flexible sensing elements being configured to deflect in response to the applied force received by the protective platform and transferred to the force sensor, and the one or more piezoresistive strain gauges providing an output signal proportional to the applied force, wherein the force sensor defines a gap at the center thereof, the gap being arranged between the protective platform and the force sensor, and a depth of the gap being configured to limit an amount of deflection of the flexible sensing elements, wherein the protective platform is above the flexible sensing elements in a thickness direction, and wherein the plurality of peripheral points are arranged over the flexible sensing elements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for manufacturing a MEMS force die, comprising:
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etching an upper side of a sensor wafer to form a gap and at least one linking area; etching a bottom side of the sensor wafer to form at least one diaphragm; forming one or more piezoresistive strain gauges on the diaphragm; bonding the at least one linking area of the sensor wafer to a protective platform wafer to form bonded areas at a plurality of peripheral points, wherein the gap is arranged between the bonded sensor wafer and protective platform wafer; and dicing the bonded sensor wafer and protective platform wafer along one or more lines intersecting the bonded areas to form a plurality of flexible sensing elements from the diaphragm, the flexible sensing elements being configured to deflect in response to an applied force received by the diced protective platform wafer and transferred to the diced sensor wafer, and the one or more piezoresistive strain gauges providing an output signal proportional to the applied force, wherein a depth of the gap is configured to limit an amount of deflection of the flexible sensing elements, wherein the gap is at a center of the diced sensor wafer and the plurality of peripheral points are along at least a portion of an outer edge of the diced sensor wafer, wherein each of the flexible sensing elements has a thickness less than a thickness at the center of the diced sensor wafer, wherein the diced protective platform wafer is above the flexible sensing elements in a thickness direction, wherein the one or more piezoresistive strain gauges are arranged on an upper surface of the flexible sensing elements, and wherein the plurality of peripheral points are arranged over the flexible sensing elements. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification