Method and apparatus for nitride spacer etch process implementing in situ interferometry endpoint detection and non-interferometry endpoint monitoring
First Claim
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1. A method for fabricating a spacer of a gate structure, the method comprising:
- performing a first etch process implementing a first etchant gas, the first etch process configured to remove a portion of a spacer layer, leaving a thin spacer layer, the first etch process configured to implement an interferometry endpoint (IEP) detection method to detect the removal of the portion of the spacer layer; and
performing a second etch process implementing a second etchant gas, the second etch process including monitoring by a non-IEP etch endpoint process, the second etch process configured to remove the thin spacer layer, leaving the spacer for the gate structure,wherein the second etchant gas includes a combination of O2, HBr, and SF6.
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Abstract
A method for fabricating a spacer of a gate structure is provided. The method performing a first etch process implementing a first etchant gas. The first etch process is configured to implement an interferometry endpoint (IEP) detection method to detect a removal of a portion of a spacer layer having a specific thickness from over the surface of the substrate, thus leaving a thin spacer layer. The method further includes performing a second etch process for a predetermined period of time implementing a second etchant gas. The second etch process is configured to remove the thin spacer layer, leaving the spacer for the gate structure.
29 Citations
18 Claims
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1. A method for fabricating a spacer of a gate structure, the method comprising:
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performing a first etch process implementing a first etchant gas, the first etch process configured to remove a portion of a spacer layer, leaving a thin spacer layer, the first etch process configured to implement an interferometry endpoint (IEP) detection method to detect the removal of the portion of the spacer layer; and performing a second etch process implementing a second etchant gas, the second etch process including monitoring by a non-IEP etch endpoint process, the second etch process configured to remove the thin spacer layer, leaving the spacer for the gate structure, wherein the second etchant gas includes a combination of O2, HBr, and SF6. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for fabricating a silicon nitride spacer, the method comprising:
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performing a first etch process implementing a first etchant gas in a plasma chamber, the first etch process configured to control a removal of a portion of a silicon nitride layer from over a surface of a substrate by monitoring a light reflected by the silicon nitride layer, the first etch process further configured to leave a thin silicon nitride layer over the surface of the substrate and to maintain a thickness of the thin silicon nitride layer substantially uniform throughout the surface of the substrate and a gate structure formed thereon, the first etchant gas configured to include a combination of CF4, HBr, and O2; and performing a second etch process implementing a second etchant gas, the second etch process including monitoring an optical signal produced by a second plasma during the second etch operation, the second etch process configured to remove the thin silicon nitride layer, leaving the silicon nitride spacer for the gate structure. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method for fabricating a nitride spacer of a gate structure, the method comprising:
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performing a first etch process using a first etchant gas, the first etch process implementing an interferometry endpoint (IEP) detection process to detect a removal of a portion of a nitride spacer layer; discontinuing the first etch process upon removing the portion of the nitride spacer layer, leaving a thin nitride spacer layer; performing a second etch process using a second etchant gas implementing optical emission spectroscopy (OES) endpoint monitoring process, the second etch process configured to remove the thin nitride spacer layer, leaving the nitride spacer for the gate structure; and discontinuing the second etch process in response to the OES monitoring process, wherein the first etchant gas includes a combination of C2F6, CH2F2, and O2 and the second etchant gas includes a combination of O2, HBr, and SF6, the first etchant gas includes a combination of CF4, CH2F2, and O2 and the second etchant gas includes a combination of O2, HBr, and SF6, the first etchant gas includes a combination of CF4, HBr, and O2 and the second etchant gas includes a combination of C2F6, CH2F2, and O2, or the first etchant gas includes a combination of CF4, HBr, O2 and the second etchant gas includes a combination of O2, HBr, and SF6. - View Dependent Claims (16, 17, 18)
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Specification