Etching back and selective deposition of metal gate
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsPeng-Soon Lim, Cheng-Lung Hung, Mao-Lin Huang, Weng Chang
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Abstract
A method includes forming a dummy gate stack, forming a dielectric layer, with the dummy gate stack located in the dielectric layer, removing the dummy gate stack to form a opening in the dielectric layer, forming a metal layer extending into the opening, and etching back the metal layer. The remaining portions of the metal layer in the opening have edges lower than a top surface of the dielectric layer. A conductive layer is selectively deposited in the opening. The conductive layer is over the metal layer, and the metal layer and the conductive layer in combination form a replacement gate.
Claims20
A method comprising:
- removing a dummy gate stack in a dielectric layer to form a trench between gate spacers;
- forming a gate dielectric layer extending into the trench;
- forming a metal layer extending into the trench and over the gate dielectric layer;
- forming a protection layer extending into the trench and over the metal layer;
- etching back the protection layer until a top surface of a portion of the protection layer is lower than a top surface of the dielectric layer;
- etching first portions of the gate dielectric layer and second portions of the metal layer in the trench, wherein the protection layer is used as an etching mask during the etching, wherein after the etching, a first top end of the gate dielectric layer is lower than second top ends of the gate spacers, and higher than third top ends of the metal layer;
- and
- after the metal layer is etched, depositing a conductive layer in the trench and on the metal layer, wherein the conductive layer is selectively deposited on the metal layer.
A method comprising:
- forming an inter-layer dielectric;
- removing a first dummy gate stack and a second dummy gate stack to form a first opening and a second opening, respectively, in the inter-layer dielectric;
- forming a gate dielectric layer extending into both of the first opening and the second opening;
- depositing a metal-containing layer, wherein the metal-containing layer comprises a first portion fully filling the first opening, and a second portion partially filling the second opening;
- performing an etching process to etch-back both of the first portion and the second portion of the metal-containing layer;
- and
- selectively depositing a conductive layer in the second opening and on the second portion of the metal-containing layer, wherein at a time a part of the conductive layer has been deposited and before the selectively depositing is finished, a top surface of the inter-layer dielectric is exposed.
A method comprising:
- depositing a high-k dielectric layer extending into a first opening and a second opening in an inter-layer dielectric, wherein a gate spacer is located between the high-k dielectric layer and the inter-layer dielectric;
- depositing a first metal layer fully filling the first opening and partially filling the second opening;
- forming a protection layer over the first metal layer and in the second opening;
- etching portions of the first metal layer and the high-k dielectric layer in the first opening and the second opening, wherein the protection layer is used as an etching mask;
- selectively depositing a second metal layer in the first opening and the second opening and over portions of the first metal layer in the first opening and the second opening;
- and
- forming a gate contact plug extending into the opening to electrically couple to the second metal layer.
Dependencies are inferred from the claim text.