Pressure sensor adjustment using backside mask
First Claim
Patent Images
1. A pressure sensor comprising:
- a diaphragm and a sidewall, the sidewall having an interior side defining a backside cavity, the backside cavity extending from a portion of an insulator layer directly in contact with the diaphragm to a backside opening,wherein the interior side of the sidewall is formed using a deep reactive ion etch and is substantially orthogonal to the diaphragm,wherein the deep reactive ion etch begins at the backside opening and etches towards the diaphragm at a rate that is substantially reduced when the insulator layer is reached, andwherein the backside opening forms a cross shape.
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Abstract
Methods and apparatus for an absolute or gauge pressure sensor having a backside cavity with a substantially vertical interior sidewall. The backside cavity is formed using a DRIE etch or other MEMS micro-machining technique. The backside cavity has an opening that is cross shaped, where the dimensions of the cross may be varied to adjust pressure sensor sensitivity. The cross may have one or more rounded corners to reduce peak stress, for example, the interior corners may be rounded. A sensing conductor may be routed over one or more corners including the interior corners to detect breakage.
23 Citations
28 Claims
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1. A pressure sensor comprising:
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a diaphragm and a sidewall, the sidewall having an interior side defining a backside cavity, the backside cavity extending from a portion of an insulator layer directly in contact with the diaphragm to a backside opening, wherein the interior side of the sidewall is formed using a deep reactive ion etch and is substantially orthogonal to the diaphragm, wherein the deep reactive ion etch begins at the backside opening and etches towards the diaphragm at a rate that is substantially reduced when the insulator layer is reached, and wherein the backside opening forms a cross shape. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A pressure sensor comprising:
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a first silicon layer comprising a diaphragm; an insulator layer below the first silicon layer; a second silicon layer below the insulator layer and having a backside cavity defined by a sidewall, a backside opening, and a portion of the insulator layer below and directly in contact with the diaphragm, wherein the backside cavity is formed using a deep reactive ion etch and the sidewall is substantially orthogonal to the diaphragm, wherein the backside opening forms a cross shape. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A pressure sensor comprising:
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a first silicon layer having a top side and a bottom side and comprising a diaphragm; an insulator layer having a top side and a bottom side, the top side in contact with the bottom side of the first silicon layer; a second silicon layer having a top side and a bottom side, the top side in contact with the bottom side of the insulator layer and having a backside cavity defined by a sidewall, a portion of the bottom side of the insulator layer, and a backside opening in the bottom side of the second silicon layer, wherein the backside cavity is formed using a deep reactive ion etch and the sidewall is substantially orthogonal to the diaphragm, wherein the backside opening forms a cross shape. - View Dependent Claims (24, 25, 26, 27, 28)
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Specification