MULTICOMPONENT SACRIFICIAL STRUCTURE
First Claim
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1. An apparatus comprising a microelectromechanical systems device, wherein the micromechanical systems device comprises:
- a sacrificial structure formed over a first structural layer; and
a second structural layer formed over the sacrificial structure, whereinthe second structural layer comprises a plurality of etchant access openings extending through the second structural layer,the sacrificial structure comprises a first portion proximal to the first structural layer and a second portion distal to the first structural layer,one of the first portion and the second portion is selectively etchable in the presence the other of the first portion and the second portion, andthe sacrificial structure is selectively etchable in the presence of the first structural layer and the second structural layer.
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Abstract
A MEMS comprising a sacrificial structure, which comprises a faster etching portion and a slower etching portion, exhibits reduced damage to structural features when in forming a cavity in the MEMS by etching away the sacrificial structure. The differential etching rates mechanically decouple structural layers, thereby reducing stresses in the device during the etching process. Methods and systems are also provided.
18 Citations
51 Claims
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1. An apparatus comprising a microelectromechanical systems device, wherein the micromechanical systems device comprises:
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a sacrificial structure formed over a first structural layer; and a second structural layer formed over the sacrificial structure, wherein the second structural layer comprises a plurality of etchant access openings extending through the second structural layer, the sacrificial structure comprises a first portion proximal to the first structural layer and a second portion distal to the first structural layer, one of the first portion and the second portion is selectively etchable in the presence the other of the first portion and the second portion, and the sacrificial structure is selectively etchable in the presence of the first structural layer and the second structural layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method of fabricating a microelectromechanical systems device, the method comprising:
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forming over a first structural layer a sacrificial structure comprising a first portion proximal to the first structural layer and a second portion distal to the first structural layer, wherein the sacrificial structure is selectively etchable in the presence of the first structural layer and the second structural layer, and one of the first portion and the second portion is selectively etchable in the presence of the other of the first portion and the second portion; forming a second structural layer over the sacrificial structure; and forming a plurality of etchant access openings extending through the second structural layer. - View Dependent Claims (28, 29, 30, 31, 32, 33)
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34. A method of manufacturing a microelectromechanical systems device comprising:
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forming a sacrificial layer over a first layer; forming a second layer over the sacrificial layer; selectively etching the sacrificial layer from between the first layer and the second layer to form at least one pillar extending between the first layer and the second layer; and mechanically decoupling the sacrificial layer from at least one of the first layer and the second layer before etching away the at least one pillar. - View Dependent Claims (35, 36, 37)
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38. An apparatus comprising a microelectromechanical systems device, wherein the micromechanical systems device comprises:
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a first sacrificial layer contacting a first structural layer; a second sacrificial layer formed over the first sacrificial layer; and a second structural layer contacting the second sacrificial layer, wherein the first sacrificial layer and the second sacrificial layer are selectively etchable in the presence of the first structural layer and the second structural layer using a preselected etchant, and one of the first sacrificial layer and second sacrificial layer is etched by the preselected etchant at faster rate than the other. - View Dependent Claims (39)
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40. An apparatus comprising a microelectromechanical systems device, wherein the micromechanical systems device comprises:
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a dielectric layer formed over a first conductive layer; a sacrificial structure formed over the dielectric layer; and a second conductive layer formed over the sacrificial structure, wherein the sacrificial structure is selectively etchable in the presence of the dielectric layer and the second conductive layer using a preselected etchant, and the sacrificial structure comprises a faster etching portion and a slower etching portion with respect to the preselected etchant. - View Dependent Claims (41)
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42. An apparatus comprising a microelectromechanical systems device, wherein the micromechanical systems device comprises:
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a compositionally non-uniform sacrificial structure formed over a first structural layer; and a second structural layer formed over the sacrificial structure, wherein the second structural layer comprises a plurality of etchant access openings extending through the second structural layer, the sacrificial structure is selectively etchable in the presence of the first structural layer and the second structural layer, and a preselected etchant etches the sacrificial structure non-uniformly.
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43. An apparatus comprising a microelectromechanical systems device, wherein the micromechanical systems device comprises:
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a first structural means for supporting the microelectromechanical systems device; a sacrificial means for forming a cavity in the microelectromechanical systems device; and a second structural means for actuating the microelectromechanical systems device, wherein the second structural means comprises a plurality of etchant access means for contacting the sacrificial means with an etchant means, and the sacrificial means comprises a faster etching portion and a slower etching portion. - View Dependent Claims (44, 45, 46)
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47. A method of manufacturing a microelectromechanical systems device comprising:
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forming a sacrificial structure over a first layer; forming a second layer over the sacrificial structure; and selectively etching away the sacrificial structure substantially completely from between the first layer and the second layer using a preselected etchant, wherein the sacrificial structure comprises a faster etching portion and a slower etching portion with respect to the preselected etchant. - View Dependent Claims (48)
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49. An apparatus comprising a microelectromechanical systems device, wherein the micromechanical systems device comprises:
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a sacrificial structure formed over a first structural layer; and a second structural layer formed over the sacrificial structure, wherein the sacrificial structure comprises a first portion and a second portion, one of the first portion and the second portion has a faster intrinsic etching rate using a preselected etchant, the sacrificial structure is selectively etchable in the presence of the first structural layer and the second structural layer using the preselected etchant, and an aspect ratio of a width or length to thickness of the sacrificial structure is at least about 50;
1. - View Dependent Claims (50, 51)
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Specification