Ultra-high aspect ratio dielectric etch
AssigneeLam Research Corporation
InventorsKyeong-Koo Chi, Erik A. Edelberg
Life of this patent
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Abstract
A method for etching an ultra high aspect ratio feature in a dielectric layer through a carbon based mask is provided. The dielectric layer is selectively etched with respect to the carbon based mask, wherein the selective etching provides a net deposition of a fluorocarbon based polymer on the carbon based mask. The selective etch is stopped. The fluorocarbon polymer is selectively removed with respect to the carbon based mask, so that the carbon based mask remains, using a trimming. The selectively removing the fluorocarbon polymer is stopped. The dielectric layer is again selectively etched with respect to the carbon based mask, wherein the second selectively etching provides a net deposition of a fluorocarbon based polymer on the carbon based mask.
Claims18
A method for etching an ultra high aspect ratio feature in a dielectric layer through a carbon based mask, comprising:
- a first selectively etching the dielectric layer with respect to the carbon based mask, wherein the first selectively etching provides a selective etch of the dielectric layer, while depositing a net deposition of a fluorocarbon based polymer on the carbon based mask;
- stopping the selective etch;
- selectively remove the fluorocarbon polymer with respect to the carbon based mask, so that the carbon based mask remains, using a trimming;
- stopping the selectively removing the fluorocarbon polymer;
- and
- a second selectively etching the dielectric layer with respect to the carbon based mask, wherein the second selectively etching provides a selective etch of the dielectric layer, while depositing a net deposition of a fluorocarbon based polymer on the carbon based mask.
A method for etching a plurality of features with an aspect ratio of at least 30:1 in a single dielectric layer through an amorphous carbon mask, comprising:
- a first selectively etching the dielectric layer with respect to the amorphous carbon mask, wherein the first selectively etching provides a selective etch of the dielectric layer, while depositing a net deposition of a fluorocarbon based polymer on the amorphous carbon mask, comprising:
- providing a gas comprising a fluorocarbon containing molecule and an oxygen containing molecule to a process chamber;
- forming the gas into a plasma;
- and
- stopping the selective etch;
- selectively remove the fluorocarbon polymer with respect to the amorphous carbon mask with a selectivity of at least 1.1 to 1, so that the amorphous carbon mask remains and a net fluorocarbon polymer is removed using a trimming, comprising:
- providing a trimming gas, comprising an oxygen containing gas for ashing the fluorocarbon polymer;
- energizing the trimming gas to form a plasma;
- and
- stopping the selectively removing the fluorocarbon polymer;
- and
- a second selectively etching the dielectric layer with respect to the amorphous carbon mask, wherein the second selectively etching provides a selective etch of the dielectric layer, while depositing a net deposition of a fluorocarbon based polymer on the amorphous carbon mask.
Dependencies are inferred from the claim text.