Spacers with rectangular profile and methods of forming the same
First Claim
Patent Images
1. A method comprising:
- forming a spacer layer on a first top surface and sidewalls of a patterned feature, wherein the patterned feature is overlying a base layer, wherein the spacer layer comprises first horizontal portions directly on the base layer, and the first horizontal portions cover an entire top surface of the base layer, with the entire top surface being between the patterned feature and a neighboring patterned feature;
forming a protection layer contacting a second top surface and a sidewall surface of the spacer layer, wherein the protection layer comprises second horizontal portions over the first horizontal portions;
removing the second horizontal portions of the protection layer, wherein vertical portions of the protection layer remain after the removing;
etching the spacer layer using the remaining vertical portions of the protection layer as an etching mask to remove all horizontal portions of the spacer layer, wherein the vertical portions of the spacer layer and the remaining vertical portions of the protection layer remain to form spacers;
after the etching the spacer layer, removing the patterned feature;
etching the base layer and the vertical portions of the protection layer to form a trench in the base layer, wherein the spacers are used as an etching mask;
filling the trench with a metal; and
removing the spacers.
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Abstract
A method includes forming a spacer layer on a top surface and sidewalls of a patterned feature, wherein the patterned feature is overlying a base layer, A protection layer is formed to contact a top surface and a sidewall surface of the spacer layer. The horizontal portions of the protection layer are removed, wherein vertical portions of the protect layer remain after the removal. The spacer layer is etched to remove horizontal portions of the spacer layer, wherein vertical portions of the spacer layer remain to form parts of spacers.
16 Citations
13 Claims
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1. A method comprising:
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forming a spacer layer on a first top surface and sidewalls of a patterned feature, wherein the patterned feature is overlying a base layer, wherein the spacer layer comprises first horizontal portions directly on the base layer, and the first horizontal portions cover an entire top surface of the base layer, with the entire top surface being between the patterned feature and a neighboring patterned feature; forming a protection layer contacting a second top surface and a sidewall surface of the spacer layer, wherein the protection layer comprises second horizontal portions over the first horizontal portions; removing the second horizontal portions of the protection layer, wherein vertical portions of the protection layer remain after the removing; etching the spacer layer using the remaining vertical portions of the protection layer as an etching mask to remove all horizontal portions of the spacer layer, wherein the vertical portions of the spacer layer and the remaining vertical portions of the protection layer remain to form spacers; after the etching the spacer layer, removing the patterned feature; etching the base layer and the vertical portions of the protection layer to form a trench in the base layer, wherein the spacers are used as an etching mask; filling the trench with a metal; and removing the spacers. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method comprising:
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forming a spacer layer comprising; a top portion on a top surface of a first and a second patterned feature; vertical portions on opposite sidewalls of the first and the second patterned features; and first horizontal portions with bottom surfaces contacting top surface of a base layer, wherein the first horizontal portions extend from the first patterned feature to the second patterned feature; performing a nitridation or an oxidation to convert a surface layer of the spacer layer into a protection layer, wherein a bottom layer of the spacer layer remains after the nitridation or the oxidation; performing an anisotropic etching to remove a horizontal portion of the protection layer, wherein vertical portions of the protection layer remains on sidewalls of remaining portions of the vertical portions of the spacer layer; and removing a portion of the bottom layer in the top portion of the spacer layer using the vertical portions of the protection layer as an etching mask, wherein remaining portions of the vertical portions of the spacer layer and the vertical portions of the protection layer remain as masks; removing the first and the second patterned features; etching the base layer using the masks as an etching mask; and removing the remaining portions of the vertical portions of the spacer layer and the vertical portions of the protection layer. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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Specification