3D stacked piezoresistive pressure sensor
First Claim
1. A pressure sensor device comprising:
- a MEMS pressure sensing element having first and second sides with a flexible diaphragm and a Wheatstone bridge circuit on the first side;
a first integrated circuit comprising a substrate with first and second sides, electronic circuitry formed into a predetermined portion of the first side and a recess formed into the second side, the second side of the first integrated circuit being attached to the first side of the MEMS pressure sensing element, the recess of the first integrated circuit and the first side of the MEMS pressure sensing element defining a substantially evacuated cavity;
a first plurality of conductive vias formed into the first integrated circuit substrate such that the first plurality of vias extend through the substrate and electrically connect the Wheatstone bridge circuit of the MEMS pressure sensing element to the circuitry formed into the first side of the first integrated circuit; and
at least one of;
i) a layer of silicon dioxide between the first side of the MEMS pressure sensing element and the second side of the first integrated circuit, the layer of silicon dioxide forming a silicon fusion bond between the MEMS pressure sensing element and the integrated circuit; and
an intermetallic bond formed between at least one of the conductive vias and an electrical contact on the first side of the MEMS pressure sensing element;
andii) a layer of glass frit located between the first side of the MEMS pressure sensing element and the second side of the first integrated circuit, the layer of glass frit forming a bond between the MEMS pressure sensing element and the first integrated circuit; and
an electrically conductive protuberance between at least one of the conductive vias and an electrical contact on the first side of the MEMS pressure sensing element.
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Accused Products
Abstract
In a microelectromechanical system (MEMS) pressure sensor, thin and fragile bond wires that are used in the prior art to connect a MEMS pressure sensing element to an application specific integrated circuit (ASIC) for the input and output signals between these two chips are replaced by stacking the ASIC on the MEMS pressure sensing element and connecting each other using conductive vias formed in the ASIC. Gel used to protect the bond wires, ASIC and MEMS pressure sensing element can be eliminated if bond wires are no longer used. Stacking the ASIC on the MEMS pressure sensing element and connecting them using conductive vias enables a reduction in the size and cost of a housing in which the devices are placed and protected.
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Citations
28 Claims
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1. A pressure sensor device comprising:
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a MEMS pressure sensing element having first and second sides with a flexible diaphragm and a Wheatstone bridge circuit on the first side; a first integrated circuit comprising a substrate with first and second sides, electronic circuitry formed into a predetermined portion of the first side and a recess formed into the second side, the second side of the first integrated circuit being attached to the first side of the MEMS pressure sensing element, the recess of the first integrated circuit and the first side of the MEMS pressure sensing element defining a substantially evacuated cavity; a first plurality of conductive vias formed into the first integrated circuit substrate such that the first plurality of vias extend through the substrate and electrically connect the Wheatstone bridge circuit of the MEMS pressure sensing element to the circuitry formed into the first side of the first integrated circuit; and at least one of; i) a layer of silicon dioxide between the first side of the MEMS pressure sensing element and the second side of the first integrated circuit, the layer of silicon dioxide forming a silicon fusion bond between the MEMS pressure sensing element and the integrated circuit; and
an intermetallic bond formed between at least one of the conductive vias and an electrical contact on the first side of the MEMS pressure sensing element;and ii) a layer of glass frit located between the first side of the MEMS pressure sensing element and the second side of the first integrated circuit, the layer of glass frit forming a bond between the MEMS pressure sensing element and the first integrated circuit; and
an electrically conductive protuberance between at least one of the conductive vias and an electrical contact on the first side of the MEMS pressure sensing element. - View Dependent Claims (2, 3, 4, 5)
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6. A pressure sensor device comprising:
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a MEMS pressure sensing element having first and second sides with a flexible diaphragm and a Wheatstone bridge circuit on the first side; a first integrated circuit comprising a substrate with first and second sides, electronic circuitry formed into a predetermined portion of the first side and a recess formed into the second side, the second side of the first integrated circuit being attached to the first side of the MEMS pressure sensing element, the recess of the first integrated circuit and the first side of the MEMS pressure sensing element defining a cavity; a first plurality of conductive vias formed into the first integrated circuit substrate such that the first plurality of vias extend through the substrate and electrically connect the Wheatstone bridge circuit of the MEMS pressure sensing element to the circuitry formed into the first side of the first integrated circuit; and at least one of; i) a layer of silicon dioxide between the first side of the MEMS pressure sensing element and the second side of the first integrated circuit, the layer of silicon dioxide forming a silicon fusion bond between the MEMS pressure sensing element and the integrated circuit, the second side further comprising at least one trench formed to extend into the recess; and
an intermetallic bond formed between at least one of the conductive vias and an electrical contact on the first side of the MEMS pressure sensing element;and ii) a layer of glass frit located between the first side of the MEMS pressure sensing element and the second side of the first integrated circuit, the layer of glass frit forming a bond between the MEMS pressure sensing element and the first integrated circuit; and
an electrically conductive protuberance between at least one of the conductive vias and an electrical contact on the first side of the MEMS pressure sensing element, wherein the layer of glass frit is patterned to provide at least one media path through the layer of glass fit, the media path being configured to allow a predetermined fluid to pass through the media path and to the recess formed into the second side of the first integrated circuit. - View Dependent Claims (7, 8, 9)
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10. A pressure sensor module comprising:
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a pressure sensor device comprising; a MEMS pressure sensing element having first and second sides with a flexible diaphragm and a Wheatstone bridge circuit on the first side; a first integrated circuit comprising a substrate with first and second sides, electronic circuitry formed into a predetermined portion of the first side and a recess formed into the second side, the second side of the first integrated circuit being attached to the first side of the MEMS pressure sensing element, the recess of the first integrated circuit and the first side of the MEMS pressure sensing element defining a substantially evacuated cavity; and a first plurality of conductive vias formed into the first integrated circuit substrate such that the first plurality of vias extend through the substrate and electrically connect the Wheatstone bridge circuit of the MEMS pressure sensing element to the circuitry formed into the first side of the first integrated circuit; a housing having a pocket that encloses the pressure sensor device and a pressure port configured to allow a predetermined fluid to apply pressure to the diaphragm; and a lead frame that extends from an electrical contact on the first side of the first integrated circuit through the housing, the electrical contact on the first side of the first integrated circuit comprising at least one of an electrically conductive protuberance and an electrically conductive adhesive. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A pressure sensor module comprising:
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a pressure sensor device comprising; a MEMS pressure sensing element having first and second sides with a flexible diaphragm and a Wheatstone bridge circuit on the first side; a first integrated circuit comprising a substrate with first and second sides, electronic circuitry formed into a predetermined portion of the first side and a recess formed into the second side, the second side of the first integrated circuit being attached to the first side of the MEMS pressure sensing element, the recess of the first integrated circuit and the first side of the MEMS pressure sensing element defining a substantially evacuated cavity; and a first plurality of conductive vias formed into the first integrated circuit substrate such that the first plurality of vias extend through the substrate and electrically connect the Wheatstone bridge circuit of the MEMS pressure sensing element to the circuitry formed into the first side of the first integrated circuit; and at least one of; i) a layer of silicon dioxide between the first side of the MEMS pressure sensing element and the second side of the first integrated circuit, the layer of silicon dioxide forming a silicon fusion bond between the MEMS pressure sensing element and the integrated circuit; and
an intermetallic bond formed between at least one of the conductive vias and an electrical contact on the first side of the MEMS pressure sensing element;and ii) a layer of glass frit located between the first side of the MEMS pressure sensing element and the second side of the first integrated circuit, the layer of glass frit forming a bond between the MEMS pressure sensing element and the first integrated circuit; and
an electrically conductive protuberance between at least one of the conductive vias and an electrical contact on the first side of the MEMS pressure sensing element;a housing having a pocket that encloses the pressure sensing device and a pressure port configured to allow a predetermined fluid to apply pressure to the diaphragm; a lead frame that extends from inside the pocket through the housing; a bond wire that extends from an electrical contact on the first side of the first integrated circuit to the lead frame; and an adhesive layer located between the second side of the MEMS pressure sensing element and an interior surface of the pocket through which the pressure port is formed, the adhesive layer surrounding and sealing the pressure port to the second side of the MEMS pressure sensing element. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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25. A pressure sensor module comprising:
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a pressure sensor device comprising; a MEMS pressure sensing element having first and second sides with a flexible diaphragm and a Wheatstone bridge circuit on the first side; a first integrated circuit comprising a substrate with first and second sides, electronic circuitry formed into a predetermined portion of the first side and a recess formed into the second side, the second side of the first integrated circuit being attached to the first side of the MEMS pressure sensing element, the recess of the first integrated circuit and the first side of the MEMS pressure sensing element defining a cavity; a first plurality of conductive vias formed into the first integrated circuit substrate such that the first plurality of vias extend through the substrate and electrically connect the Wheatstone bridge circuit of the MEMS pressure sensing element to the circuitry formed into the first side of the first integrated circuit; and at least one of; i) a layer of silicon dioxide between the first side of the MEMS pressure sensing element and the second side of the first integrated circuit, the layer of silicon dioxide forming a silicon fusion bond between the MEMS pressure sensing element and the integrated circuit, the second side further comprising at least one trench formed to extend into the recess; and
an intermetallic bond formed between at least one of the conductive vias and an electrical contact on the first side of the MEMS pressure sensing element;and ii) a layer of glass frit located between the first side of the MEMS pressure sensing element and the second side of the first integrated circuit, the layer of glass frit forming a bond between the MEMS pressure sensing element and the first integrated circuit; and
an electrically conductive protuberance between at least one of the conductive vias and an electrical contact on the first side of the MEMS pressure sensing element wherein the layer of glass frit is patterned to provide at least one media path through the layer of glass frit, the media path being configured to allow a predetermined fluid to pass through the media path and to the recess formed into the second side of the first integrated circuit;a housing having a pocket that encloses the pressure sensing device and a pressure port configured to allow a predetermined fluid to apply pressure to the diaphragm; a lead frame that extends from inside the pocket through the housing; a bond wire that extends from an electrical contact on the first side of the first integrated circuit to the lead frame; and an adhesive layer located between the second side of the MEMS pressure sensing element and an interior surface of the pocket through which the pressure port is formed, the adhesive layer surrounding and sealing the pressure port to the second side of the MEMS pressure sensing element. - View Dependent Claims (26, 27, 28)
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Specification