Selective etching of MEMS using gaseous halides and reactive co-etchants
First Claim
1. A method for fabricating a microelectromechanical systems device comprising:
- providing a substrate in an etching chamber;
contacting a microelectromechanical systems device formed on the substrate with a vapor phase etchant comprising a gaseous halide and a co-etchant by flowing the vapor phase etchant and the co-etchant into the etching chamber, whereinthe microelectromechanical systems device comprises a target material and a structural material;
the target material and the structural material are both etchable by the gaseous halide with an etching selectivity between the target material and the structural material of at least about 50;
1 in the absence of the co-etchant; and
the co-etchant is present in an amount effective to improve the etching selectivity between the target material and the structural material by at least about 2-times compared with the etching selectivity in the absence of the co-etchant.
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Accused Products
Abstract
A method for etching a target material in the presence of a structural material with improved selectivity uses a vapor phase etchant and a co-etchant. Embodiments of the method exhibit improved selectivities of from at least about 2-times to at least about 100-times compared with a similar etching process not using a co-etchant. In some embodiments, the target material comprises a metal etchable by the vapor phase etchant. Embodiments of the method are particularly useful in the manufacture of MEMS devices, for example, interferometric modulators. In some embodiments, the target material comprises a metal etchable by the vapor phase etchant, for example, molybdenum and the structural material comprises a dielectric, for example silicon dioxide.
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Citations
37 Claims
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1. A method for fabricating a microelectromechanical systems device comprising:
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providing a substrate in an etching chamber; contacting a microelectromechanical systems device formed on the substrate with a vapor phase etchant comprising a gaseous halide and a co-etchant by flowing the vapor phase etchant and the co-etchant into the etching chamber, wherein the microelectromechanical systems device comprises a target material and a structural material; the target material and the structural material are both etchable by the gaseous halide with an etching selectivity between the target material and the structural material of at least about 50;
1 in the absence of the co-etchant; andthe co-etchant is present in an amount effective to improve the etching selectivity between the target material and the structural material by at least about 2-times compared with the etching selectivity in the absence of the co-etchant. - 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, 35, 36, 37)
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25. A method for fabricating a microelectromechanical systems device comprising:
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contacting a microelectromechanical systems device with a vapor phase etchant means and a co-etchant means, wherein the microelectromechanical systems device comprises a metal target material and a structural material; and the co-etchant means is present in an amount effective to improve an etching selectivity between the target material and the structural material by at least 2-times compared with an etching selectivity between the target material and the structural material in the absence of the co-etchant means.
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26. A method for fabricating an interferometric modulator comprising:
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contacting an unreleased interferometric modulator with a vapor phase etchant and a vapor phase co-etchant, wherein the unreleased interferometric modulator comprises a sacrificial material in contact with a dielectric material, and at least a portion of the sacrificial material when etched away forms a cavity; and etching away substantially all of the at least a portion of the sacrificial material, wherein the co-etchant is present in an amount sufficient to improve the etching selectivity between the sacrificial material and the dielectric material by at least 2-times. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34)
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Specification