Mitigation of time dependent dielectric breakdown
First Claim
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1. A method, comprising:
- forming a dielectric layer with an opening;
forming a multilayer gate metal stack in the opening to cover sidewalls of the opening and a top surface of the dielectric layer;
depositing a spacer layer on the multilayer gate metal stack;
etching the spacer layer with an anisotropic etchback process to form spacers on portions of the multilayer gate metal stack covering the sidewalls of the opening;
depositing a metal on the multilayer gate metal stack to fill the opening; and
after depositing the metal, planarizing the top surface of the dielectric layer to remove the multilayer gate metal stack and the metal from the top surface of the dielectric layer.
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Abstract
The present disclosure describes an exemplary replacement gate process that forms spacer layers in a gate stack to mitigate time dependent dielectric breakdown (TDDB) failures. For example, the method can include a partially fabricated gate structure with a first recess. A spacer layer is deposited into the first recess and etched with an anisotropic etchback (EB) process to form a second recess that has a smaller aperture than the first recess. A metal fill layer is deposited into the second recess.
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Citations
20 Claims
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1. A method, comprising:
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forming a dielectric layer with an opening; forming a multilayer gate metal stack in the opening to cover sidewalls of the opening and a top surface of the dielectric layer; depositing a spacer layer on the multilayer gate metal stack; etching the spacer layer with an anisotropic etchback process to form spacers on portions of the multilayer gate metal stack covering the sidewalls of the opening; depositing a metal on the multilayer gate metal stack to fill the opening; and after depositing the metal, planarizing the top surface of the dielectric layer to remove the multilayer gate metal stack and the metal from the top surface of the dielectric layer. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A structure, comprising:
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a substrate; two opposing spacers on the substrate; a first dielectric disposed over the substrate between the two opposing spacers; a second dielectric conformally deposited between the two opposing spacers and over the first dielectric; a multilayer gate metal stack conformally deposited over the second dielectric, wherein the multilayer gate metal stack comprises a first recess with side surfaces and a bottom surface between the side surfaces, wherein the side surfaces and the bottom surface expose a topmost layer of the multilayer gate metal stack; a spacer layer disposed over the side surfaces of the first recess to form a second recess smaller than the first recess, wherein the spacer layer comprises a third dielectric; and a metal deposited into the second recess. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A method, comprising:
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providing a substrate; forming two opposing spacers on the substrate; forming a first dielectric over the substrate between the two opposing spacers; depositing a second dielectric between the two opposing spacers and over the first dielectric; depositing a multilayer gate metal stack over the second dielectric and over sides of the two opposing spacers to form a first recess with side surfaces; depositing a spacer layer over the side surfaces of the first recess to form a second recess smaller than the first recess, wherein the spacer layer comprises a third dielectric; and depositing a metal into the second recess. - View Dependent Claims (17, 18, 19, 20)
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Specification