PRESSURE SENSOR FOR HARSH MEDIA SENSING AND FLEXIBLE PACKAGING
First Claim
1. A pressure sensor element, comprising:
- a silicon cap having first and second sides, the first side including a recess extending into the cap, and the cap further having at least one insulated conductive via residing outside of the recess,a silicon die having first and second sides, the first side including a circuit, electrical interconnects, and a silicon diaphragm, the second side having a cavity extending into the die with the bottom surface being the bottom surface of the silicon diaphragm,a bonding layer attaching the first side of the silicon die to the first side of the silicon cap,the recess of the cap encapsulating the top surface of the diaphragm on the die, and the at least one conductive via in the cap electrically connecting with at least one of the electrical interconnects.
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Accused Products
Abstract
MEMS pressure sensing elements, the fabrication methods of the sensing elements, and the packaging methods using the new sensing elements are introduced to provide a way for a harsh media absolute pressure sensing and eliminating the negative effects caused by the gel used in the prior art. The invention uses vertical conductive vias to electrically connect the enclosed circuit to the outside, and uses a fusion bond method to attach a cap with the embedded conductive vias over a device die having a circuit for example a piezoresistive Wheatstone bridge to sense pressure. New packaging methods comprise a) a two-pocket housing structure and using a surface mounting method to attach a new sensing element into one pocket by a ball grid array (BGA), and b) a single pocket structure and using conventional die attach and wire bonding. Both methods can be used for harsh media pressure sensing but without the negative effects caused by the gel in prior art.
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Citations
26 Claims
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1. A pressure sensor element, comprising:
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a silicon cap having first and second sides, the first side including a recess extending into the cap, and the cap further having at least one insulated conductive via residing outside of the recess, a silicon die having first and second sides, the first side including a circuit, electrical interconnects, and a silicon diaphragm, the second side having a cavity extending into the die with the bottom surface being the bottom surface of the silicon diaphragm, a bonding layer attaching the first side of the silicon die to the first side of the silicon cap, the recess of the cap encapsulating the top surface of the diaphragm on the die, and the at least one conductive via in the cap electrically connecting with at least one of the electrical interconnects. - View Dependent Claims (2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, 26)
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5. (canceled)
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17. A pressure sensor comprised of:
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a cover with a port; a housing including first and second pockets, and at least one lead frame extending between the first and second pockets; a pressure sensor element in the first pocket; a metallic connector electrically connecting at least one lead frame with one metal bond pad of the pressure sensor element; at least one integrated circuit (IC) in the second pocket, electrically connected to the pressure sensing element via wires, lead frame and metallic connector; a gel partially filling the second pocket to cover the circuit and wire bonds. - View Dependent Claims (19, 20, 21)
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22. A pressure sensor comprised of:
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a cover; a housing with a port and lead frame, and the housing having top and bottom sides; a pressure sensor element mounted in the housing adhesive material; at least one integrated circuit (IC), electrically connected to the pressure sensing element via wires; a gel partially filling the housing to cover IC, pressure sensor element and wires. - View Dependent Claims (23, 24, 25)
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Specification