Cantilever pressure transducer
First Claim
Patent Images
1. A micromechanical device comprising:
- a frame having an opening;
at least one cantilever structure attached to said frame over a portion of a perimeter of said opening and covering a majority of said opening; and
said cantilever structure including three adjacent sublayers designated first, second and third such that said second sublayer is adjacent to said first and third sublayers, said first and third sublayers formed of substantially the same first material and having about the same average stress, and said second layer formed of a second material and having a minimum stress and a maximum stress, the difference between said maximum stress and said minimum stress being less than the magnitude of the average stress of said first sublayer.
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Abstract
Micromachined cantilever pressure transducers, which work both as microphones and as microspeakers, are disclosed. These devices are made possible by novel methods for producing flat, thin film multilayer or polymeric cantilevers.
154 Citations
29 Claims
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1. A micromechanical device comprising:
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a frame having an opening; at least one cantilever structure attached to said frame over a portion of a perimeter of said opening and covering a majority of said opening; and said cantilever structure including three adjacent sublayers designated first, second and third such that said second sublayer is adjacent to said first and third sublayers, said first and third sublayers formed of substantially the same first material and having about the same average stress, and said second layer formed of a second material and having a minimum stress and a maximum stress, the difference between said maximum stress and said minimum stress being less than the magnitude of the average stress of said first sublayer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 29)
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14. A micromechanical device, comprising:
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a substrate having first and second surfaces, and a cavity with an opening at said first surface; at least one multilayer cantilever structure attached to said first surface of said substrate over a portion of a perimeter of said opening and covering a majority of said opening; and wherein said cantilever structure includes three adjacent sublayers designated first, second and third such that said second sublayer is adjacent to said first and third sublayers, said first and third sublayers having about the same average stress, said second sublayer having a maximum stress and a minimum stress, compressive and tensile stresses considered to have opposite sign, and the magnitude of the difference between said maximum stress and said minimum stress being less than the magnitude of the average stress of said first sublayer, said first, second and third sublayers including silicon nitride.
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15. A micromechanical device comprising:
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a substrate having first and second surfaces, and a cavity with an opening at said first surface; at least one multilayer cantilever structure attached to said first surface of said substrate over a portion of a perimeter of said opening and covering a majority of said opening; and wherein said cantilever structure includes three adjacent sublayers designated first, second and third such that said second sublayer is adjacent to said first and third sublayers, said first and third sublayers having about the same average stress, said second sublayer having a maximum stress and a minimum stress, compressive and tensile stresses considered to have opposite sign, the magnitude of the difference between said maximum stress and said minimum stress being less than the magnitude of the average stress of said first sublayer, and said first and third sublayers having opposite stress gradients, said first, second and third sublayers including silicon nitride.
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16. A micromechanical device, comprising:
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a substrate having first and second surfaces, and a cavity with an opening at said first surface; at least one multilayer cantilever structure attached to said first surface of said substrate over a portion of a perimeter of said opening and covering a majority of said opening; and wherein said cantilever structure includes three adjacent sublayers designated first, second and third such that said second sublayer is adjacent to said first and third sublayers, said first and third sublayers having about the same average stress, said second sublayer having a maximum stress and a minimum stress, compressive and tensile stresses considered to have opposite sign, the magnitude of the difference between said maximum stress and minimum stress being less than the magnitude of the average stress of said first sublayer, and an average stress of said second sublayer is less than the average stress of said first sublayer, said first, second and third sublayers including silicon nitride.
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17. A method for fabrication of a polymeric cantilever structure, comprising:
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providing a first mold element having features raised above a first flat surface; coating said first surface with a polymer precursor; placing a second mold element with a second flat surface parallel to the first surface and in contact with the raised features; and polymerizing said polymer precursor.
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18. A method for fabrication of a thin film cantilever structure, comprising:
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providing an article comprising a substantially planar first thin film, said thin film having first and second exposed surfaces; growing second and third thin films on said first and second surfaces, respectively, to form a thin film multilayer; and etching at least one slit through at least part of the thin film multilayer to define at least one multilayer thin film cantilever. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification