High fidelity patterning employing a fluorohydrocarbon-containing polymer
First Claim
1. A method of forming a patterned structure comprising:
- forming a stack comprising, from bottom to top, a substrate, a hard mask layer that is not carbon-based, a soft mask layer including a carbon-based material, and a photoresist;
lithographically patterning said photoresist; and
transferring a pattern in said photoresist into said soft mask layer employing an anisotropic etch, wherein a carbon-rich polymer including carbon and fluorine is formed on sidewalls around an opening of said soft mask layer, wherein an atomic ratio of carbon to fluorine is greater than 1 within said carbon-rich polymer, wherein said anisotropic etch employs a fluorohydrocarbon-containing plasma, and said carbon-rich polymer is generated by interaction of said fluorohydrocarbon-containing plasma with said soft mask layer, and wherein said fluorohydrocarbon-containing includes ions of CxHyFz, wherein x is an integer selected from 3, 4, 5, and 6, y and z are positive integers, and y is greater than z.
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Abstract
A stack of a hard mask layer, a soft mask layer, and a photoresist is formed on a substrate. The photoresist is patterned to include at least one opening. The pattern is transferred into the soft mask layer by an anisotropic etch, which forms a carbon-rich polymer that includes more carbon than fluorine. The carbon-rich polymer can be formed by employing a fluorohydrocarbon-containing plasma generated with fluorohydrocarbon molecules including more hydrogen than fluorine. The carbon-rich polymer coats the sidewalls of the soft mask layer, and prevents widening of the pattern transferred into the soft mask. The photoresist is subsequently removed, and the pattern in the soft mask layer is transferred into the hard mask layer. Sidewalls of the hard mask layer are coated with the carbon-rich polymer to prevent widening of the pattern transferred into the hard mask.
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Citations
12 Claims
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1. A method of forming a patterned structure comprising:
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forming a stack comprising, from bottom to top, a substrate, a hard mask layer that is not carbon-based, a soft mask layer including a carbon-based material, and a photoresist; lithographically patterning said photoresist; and transferring a pattern in said photoresist into said soft mask layer employing an anisotropic etch, wherein a carbon-rich polymer including carbon and fluorine is formed on sidewalls around an opening of said soft mask layer, wherein an atomic ratio of carbon to fluorine is greater than 1 within said carbon-rich polymer, wherein said anisotropic etch employs a fluorohydrocarbon-containing plasma, and said carbon-rich polymer is generated by interaction of said fluorohydrocarbon-containing plasma with said soft mask layer, and wherein said fluorohydrocarbon-containing includes ions of CxHyFz, wherein x is an integer selected from 3, 4, 5, and 6, y and z are positive integers, and y is greater than z. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 11, 12)
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9. A method of forming a patterned structure comprising:
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forming a stack comprising, from bottom to top, a substrate, a hard mask layer that is not carbon-based, a soft mask layer including a carbon-based material, and a photoresist; lithographically patterning said photoresist; patterning said soft mask layer by transferring a pattern in said photoresist into said soft mask layer; and transferring a pattern in said soft mask layer into said hard mask layer employing an anisotropic etch, wherein a carbon-rich polymer including carbon and fluorine is formed contiguously on a top surface of said soft mask layer, on sidewalls of said soft mask layer, and on sidewalls of said hard mask layer, wherein an atomic ratio of carbon to fluorine is greater than 1 within said carbon-rich polymer, wherein said anisotropic etch employs a fluorohydrocarbon-containing plasma, and said carbon-rich polymer is generated by interaction of said fluorohydrocarbon-containing plasma with said soft mask layer, and wherein said fluorohydrocarbon-containing plasma includes ions of CpHqFr, wherein p is an integer selected from 3, 4, 5, and 6, q and r are positive integers, and q is greater than r. - View Dependent Claims (10)
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Specification