DIFFERENTIAL PRESSURE SENSOR FULL OVERPRESSURE PROTECTION DEVICE
First Claim
1. A pressure sensor die assembly for a differential pressure sensor, comprising:
- a base substrate having a first surface and including a first overpressure stop structure on the first surface;
a diaphragm structure coupled to the first surface and comprising;
a first side with a cavity section that includes a first cavity and a second cavity surrounding the first cavity, and a second side opposite from the first side;
a pressure sensing diaphragm portion having a first thickness and defined by the first cavity, the pressure sensing diaphragm portion located over and spaced apart from the first overpressure stop structure such that the first overpressure stop structure protrudes into a portion of the first cavity; and
an overpressure diaphragm portion having a second thickness and defined by the second cavity, the second thickness greater than the first thickness of the pressure sensing diaphragm portion;
wherein the pressure sensing diaphragm portion has a pressure sensing surface on the second side of the diaphragm structure opposite from the first side; and
a top cap coupled to the second side of the diaphragm structure and having a lower surface, the top cap including a second overpressure stop structure on the lower surface, wherein a gap is located between the pressure sensing surface and the second overpressure stop structure prior to overpressure being applied;
wherein when overpressure is applied to the first side of the diaphragm structure, at least some area of the pressure sensing diaphragm portion is deflected such that at least a portion of the pressure sensing surface is in contact with the second overpressure stop structure;
wherein when overpressure is applied to the second side of the diaphragm structure, at least some area of the pressure sensing diaphragm portion is deflected and supported by the first overpressure stop structure;
wherein the first and second overpressure stop structures are each sized to support substantially all of a strained area of the pressure sensing diaphragm portion at an increasing overpressure on the first or second sides of the diaphragm structure.
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Accused Products
Abstract
A pressure sensor die assembly for a differential pressure sensor comprises a base substrate including a first overpressure stop structure on a first surface, and a diaphragm structure coupled to the first surface. The diaphragm structure comprises a first side with a cavity section that includes a first cavity and a second cavity surrounding the first cavity, and a second side opposite from the first side. A pressure sensing diaphragm portion is defined by the first cavity and is located over the first overpressure stop structure. An overpressure diaphragm portion is defined by the second cavity. A top cap coupled to the second side of the diaphragm structure includes a second overpressure stop structure. The overpressure stop structures are each sized to support substantially all of a strained area of the pressure sensing diaphragm portion at an increasing overpressure on the first or second sides of the diaphragm structure.
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Citations
20 Claims
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1. A pressure sensor die assembly for a differential pressure sensor, comprising:
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a base substrate having a first surface and including a first overpressure stop structure on the first surface; a diaphragm structure coupled to the first surface and comprising; a first side with a cavity section that includes a first cavity and a second cavity surrounding the first cavity, and a second side opposite from the first side; a pressure sensing diaphragm portion having a first thickness and defined by the first cavity, the pressure sensing diaphragm portion located over and spaced apart from the first overpressure stop structure such that the first overpressure stop structure protrudes into a portion of the first cavity; and an overpressure diaphragm portion having a second thickness and defined by the second cavity, the second thickness greater than the first thickness of the pressure sensing diaphragm portion; wherein the pressure sensing diaphragm portion has a pressure sensing surface on the second side of the diaphragm structure opposite from the first side; and a top cap coupled to the second side of the diaphragm structure and having a lower surface, the top cap including a second overpressure stop structure on the lower surface, wherein a gap is located between the pressure sensing surface and the second overpressure stop structure prior to overpressure being applied; wherein when overpressure is applied to the first side of the diaphragm structure, at least some area of the pressure sensing diaphragm portion is deflected such that at least a portion of the pressure sensing surface is in contact with the second overpressure stop structure; wherein when overpressure is applied to the second side of the diaphragm structure, at least some area of the pressure sensing diaphragm portion is deflected and supported by the first overpressure stop structure; wherein the first and second overpressure stop structures are each sized to support substantially all of a strained area of the pressure sensing diaphragm portion at an increasing overpressure on the first or second sides of the diaphragm structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of fabricating one or more differential pressure sensor die assemblies with overpressure protection, the method comprising:
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providing a base wafer configured with one or more base substrates; patterning a stop wafer with one or more protruding structures; attaching the stop wafer to the base wafer such that the one or more protruding structures are respectively coupled to the one or more base substrates; removing selected portions of the stop wafer attached to the base wafer such that the one or more protruding structures remain coupled to the one or more base substrates to form a first overpressure stop structure on each base substrate; patterning a diaphragm wafer to form one or more diaphragm structures each with a two step cavity section that includes a first cavity having a first depth, and a second cavity having a second depth less than the first depth and surrounding the first cavity, wherein the one or more diaphragm structures each include a pressure sensing diaphragm portion defined by the first cavity, and an overpressure diaphragm portion that surrounds the pressure sensing diaphragm portion and is defined by the second cavity; patterning a top cap wafer to form one or more top caps each with a second overpressure stop structure on a lower surface of each top cap; attaching the patterned diaphragm wafer to the base wafer such that each first overpressure stop structure respectively protrudes into the first cavity of the one or more diaphragm structures, wherein a gap is maintained between the first overpressure stop structure and the pressure sensing diaphragm portion prior to a high side overpressure being applied to the diaphragm structure; and attaching the patterned top cap wafer to the patterned diaphragm wafer such that a gap is maintained between the second overpressure stop structure and the pressure sensing diaphragm portion prior to a low side overpressure being applied to the diaphragm structure; wherein the first and second overpressure stop structures are each sized to support substantially all of a strained area of the pressure sensing diaphragm portion at an increasing high side or low side overpressure. - View Dependent Claims (15, 16, 17, 18, 19)
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20. A differential pressure sensor, comprising:
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a base substrate including a first overpressure stop structure on a first surface; a diaphragm structure coupled to the first surface and comprising; a first side with a cavity section that includes a first cavity and a second cavity surrounding the first cavity, and a second side opposite from the first side; a pressure sensing diaphragm portion defined by the first cavity and located over the first overpressure stop structure; and an overpressure diaphragm portion defined by the second cavity; and a top cap coupled to the second side of the diaphragm structure and having a lower surface, the top cap including a second overpressure stop structure on the lower surface, wherein a gap is located between the pressure sensing diaphragm portion and the second overpressure stop structure prior to overpressure being applied; wherein the first and second overpressure stop structures are each sized to support substantially all of a strained area of the pressure sensing diaphragm portion at an increasing overpressure on the first or second sides of the diaphragm structure.
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Specification