Dual-suspension system for MEMS-based devices and method for fabricating same
First Claim
1. A method for fabricating a dual-suspension system for MEMS-based devices comprising the steps of:
- etching the geometry of an upper spring system, a lower spring system, and a proof mass into a substrate, the substrate initially comprising;
a handle wafer having a first side and a second side,a first layer of oxide covering the first side and a second layer of oxide covering the second side, anda first layer of silicon covering the first layer of oxide and a second layer of silicon covering the second layer of oxide, wherein the geometry of the upper spring system, the lower spring system, and the proof mass are etched into each of the first layer of silicon and the second layer of silicon, the regions of the substrate opposite the proof mass and adjacent to the upper spring system and the lower spring system defining a support structure;
applying a protective barrier to cover at least the exposed portions of the first layer of silicon;
etching through portions of the protective barrier and the handle wafer to define the shapes of the upper spring system, the lower spring system, and the proof mass;
removing the remainder of the protective barrier; and
removing the first layer of oxide from the areas in contact with the upper spring system and removing the second layer of oxide from the areas in contact with the lower spring system.
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Accused Products
Abstract
A method for fabricating a dual-suspension system for MEMS-based devices includes: etching the geometry of an upper spring system, a lower spring system, and a proof mass into a substrate; applying a protective barrier to cover at least the exposed portions of the first layer of silicon; etching through portions of the protective barrier and handle wafer to define the shapes of the upper spring system, lower spring system, and proof mass; removing the remainder of the protective barrier; and removing the first layer of oxide from the areas in contact with the upper spring system and removing the second layer of oxide from the areas in contact with the lower spring system. Electrical contacts may be created on the substrate. A wafer may be bonded to the support structure on a side of the substrate. A MEMS-based device fabricated from the method is also provided.
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Citations
32 Claims
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1. A method for fabricating a dual-suspension system for MEMS-based devices comprising the steps of:
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etching the geometry of an upper spring system, a lower spring system, and a proof mass into a substrate, the substrate initially comprising; a handle wafer having a first side and a second side, a first layer of oxide covering the first side and a second layer of oxide covering the second side, and a first layer of silicon covering the first layer of oxide and a second layer of silicon covering the second layer of oxide, wherein the geometry of the upper spring system, the lower spring system, and the proof mass are etched into each of the first layer of silicon and the second layer of silicon, the regions of the substrate opposite the proof mass and adjacent to the upper spring system and the lower spring system defining a support structure; applying a protective barrier to cover at least the exposed portions of the first layer of silicon; etching through portions of the protective barrier and the handle wafer to define the shapes of the upper spring system, the lower spring system, and the proof mass; removing the remainder of the protective barrier; and removing the first layer of oxide from the areas in contact with the upper spring system and removing the second layer of oxide from the areas in contact with the lower spring system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for fabricating a dual-suspension system for MEMS-based devices comprising the steps of:
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etching the geometry of an upper spring system, a lower spring system, and a proof mass into a substrate, the substrate initially comprising; a handle wafer having a first side and a second side, a first layer of oxide covering the first side and a second layer of oxide covering the second side, and a first layer of silicon covering the first layer of oxide and a second layer of silicon covering the second layer of oxide, wherein the geometry of the upper spring system, the lower spring system, and the proof mass are etched into each of the first layer of silicon and the second layer of silicon, the regions of the substrate opposite the proof mass and adjacent to the upper spring system and the lower spring system defining a support structure; applying a protective barrier to cover at least the exposed portions of the first layer of silicon; bonding a wafer to the support structure on at least one side of the substrate; etching through portions of the protective barrier and the handle wafer to define the shapes of the upper spring system, the lower spring system, and the proof mass; removing the remainder of the protective barrier; removing the first layer of oxide from the areas in contact with the upper spring system and removing the second layer of oxide from the areas in contact with the lower spring system; and creating one or more electrical contacts on at least one surface of the substrate. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28)
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29. A method for fabricating a dual-suspension system for MEMS-based devices comprising the steps of:
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etching the geometry of an upper spring system, a lower spring system, and a proof mass into a substrate, the substrate initially comprising; a handle wafer having a first side and a second side, a first layer of oxide covering the first side and a second layer of oxide covering the second side, and a first layer of silicon covering the first layer of oxide and a second layer of silicon covering the second layer of oxide, wherein the geometry of the upper spring system, the lower spring system, and the proof mass are etched into each of the first layer of silicon and the second layer of silicon, the regions of the substrate opposite the proof mass and adjacent to the upper spring system and the lower spring system defining a support structure; applying a protective barrier to cover at least the exposed portions of the first layer of silicon; bonding a wafer to the support structure on at least one side of the substrate by the steps of; applying a bonding layer of oxide to at least one portion of one side of the wafer; creating a trench in at least one portion of the second layer of silicon on the support structure; filling at least a portion of the trench with an adhesive material, aligning the portions of the wafer having the bonding layer of oxide to the trenches, and pressing the wafer to the substrate, wherein at least one bonding region is formed from the contacting of the trenches with the portions of the wafer having the bonding layer of oxide; etching through portions of the protective barrier and the handle wafer to define the shapes of the upper spring system, the lower spring system, and the proof mass; removing the remainder of the protective barrier; removing the first layer of oxide from the areas in contact with the upper spring system and removing the second layer of oxide from the areas in contact with the lower spring system; and creating one or more electrical contacts on at least one surface of the substrate. - View Dependent Claims (30, 31, 32)
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Specification