Hinged MEMS diaphragm
First Claim
1. A micromechanical structure, comprising:
- a substrate having a through hole;
a residual portion of a sacrificial oxide layer peripheral to the through hole formed on the substrate; and
a polysilicon layer overlying the through hole, patterned to have;
a planar portion;
at least one supporting portion connecting the planar portion overlying the through hole to a portion of the polysilicon layer supported on the residual portion of the sacrificial oxide layer peripheral to the through hole, the at least one supporting portion being configured to permit movement of the planar portion with respect to the substrate;
a first pattern of polysilicon stiffeners formed extending beneath the planar portion overlying the through hole, the first pattern of polysilicon stiffeners having a first depth and being configured to stiffen the planar portion; and
a second pattern of polysilicon ribs selectively disposed proximate to the at least one supporting portion, attached near a periphery of the planar portion, wherein the polysilicon ribs extend from the planar portion to a depth beyond a depth of the polysilicon stiffeners, and extend laterally beyond an edge of the planar portion.
1 Assignment
0 Petitions
Accused Products
Abstract
A micromechanical structure, comprising a substrate having a through hole; a residual portion of a sacrificial oxide layer peripheral to the hole; and a polysilicon layer overlying the hole, patterned to have a planar portion; a supporting portion connecting the planar portion to polysilicon on the residual portion; polysilicon stiffeners formed extending beneath the planar portion overlying the hole; and polysilicon ribs surrounding the supporting portion, attached near a periphery of the planar portion. The polysilicon ribs extend to a depth beyond the stiffeners, and extend laterally beyond an edge of the planar portion. The polysilicon ribs are released from the substrate during manufacturing after the planar region, and reduce stress on the supporting portion.
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Citations
20 Claims
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1. A micromechanical structure, comprising:
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a substrate having a through hole; a residual portion of a sacrificial oxide layer peripheral to the through hole formed on the substrate; and a polysilicon layer overlying the through hole, patterned to have; a planar portion; at least one supporting portion connecting the planar portion overlying the through hole to a portion of the polysilicon layer supported on the residual portion of the sacrificial oxide layer peripheral to the through hole, the at least one supporting portion being configured to permit movement of the planar portion with respect to the substrate; a first pattern of polysilicon stiffeners formed extending beneath the planar portion overlying the through hole, the first pattern of polysilicon stiffeners having a first depth and being configured to stiffen the planar portion; and a second pattern of polysilicon ribs selectively disposed proximate to the at least one supporting portion, attached near a periphery of the planar portion, wherein the polysilicon ribs extend from the planar portion to a depth beyond a depth of the polysilicon stiffeners, and extend laterally beyond an edge of the planar portion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A micromechanical structure, comprising:
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a substrate having at least one through hole; a residual portion of a sacrificial oxide layer peripheral to the at least one through hole formed on the substrate; and a polysilicon layer overlying the at least one through hole and the residual portion of the sacrificial oxide layer; each respective through hole being associated with a patterned region of the polysilicon layer comprising; a planar portion overlying the respective through hole; at least one supporting portion connecting a the planar portion to a portion of the polysilicon layer on the residual portion of the sacrificial oxide layer peripheral to the respective through hole, being configured to permit movement of the planar portion with respect to the substrate; a first pattern of polysilicon stiffeners formed extending beneath the planar portion overlying the respective through hole, configured to stiffen the planar portion; and a second pattern of polysilicon ribs selectively disposed surrounding the at least one supporting portion, attached near a periphery of the planar portion, wherein the polysilicon ribs extend from the planar portion to a depth beyond a depth of the polysilicon stiffeners, and extend laterally beyond an edge of the respective planar portion. - View Dependent Claims (10, 11, 12, 13)
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14. A micromechanical structure, comprising:
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at least one trench etched into a substrate; a sacrificial layer formed on the substrate and walls of the at least one trench; a structural layer deposited over the sacrificial layer and the trench, having at least one separated structure having a respective peripheral boundary etched from the structural layer, wherein at least a portion of the structural layer overlying portions of the at least one trench is removed, exposing a portion of the structural layer extending into the at least one trench preserved at the respective peripheral boundary, to thereby define a respective supporting member which extends across the peripheral boundary; and at least one void formed through the substrate and the sacrificial layer, configured to expose an underside of the structural layer; wherein the sacrificial layer has higher residual compressive stresses than the structural layer, such that an unconstrained region of the sacrificial layer adjacent to the structural layer is subject to mechanical distortion in response to a difference in the respective residual compressive stresses, and the portion of the sacrificial layer surrounding the exposed portion of the structural layer extending into the trench preserved at the peripheral boundary is configured to be preserved during a removal of the sacrificial layer under the structural layer through the substrate during a formation of the at least one void to prevent damage to the structural layer, and to be removed after formation of the at least one void. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification