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US 11,056,392 B2Granted
FinFET devices having gate stacks with protruding parts and method of forming the same
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsCheng-Chien Li, Wei-Shuo Ho, Huang-Chao Chang, Wei-Zhe Jhang
Life of this patent
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Abstract
A method for forming a FinFET device is described. The method includes the following steps. A substrate is patterned to form fins. Dummy gate stack is formed on the substrate and over the fins, wherein the dummy gate stack may be formed by the following steps: a dummy layer is formed; a first etching step is performed on the dummy layer with a bromine containing etching gas to form a dummy strip; a second etching step is performed on the dummy strip with a chlorine containing etching gas to form the dummy gate stack. The dummy gate stack is replaced with a gate stack.
Claims20
A method for forming a FinFET device, comprising:
- patterning a substrate to form fins;
- forming a dummy gate stack on the substrate and over the fins, wherein forming the dummy gate stack comprises:
- forming a dummy layer covering the fins;
- forming a hard mask layer over the dummy layer;
- performing a first etching step to remove portions of the dummy layer and portions of the hard mask layer with a bromine containing etching gas as a main etching gas in the first etching step to form a dummy strip and a hard mask strip, wherein after the first etching step, the dummy strip is formed with a first part located over the fins, and a plurality of tapered second parts in physical contact with sidewalls of the first part and sidewalls of the fins, and the hard mask strip overlaps with the first part of the dummy strip and does not overlap with the plurality of tapered second parts of the dummy strip, and the first etching step reveals portions of the fins;
- and
- performing a second etching step to remove portions of the plurality of tapered second parts of the dummy strip from the sidewalls of the first part and from the sidewalls of the fins with a chlorine containing etching gas to form the dummy gate stack, wherein the chlorine containing etching gas is selected as a main etching gas in the second etching step on the basis that it has a smaller molecular weight of ion as compared to the bromine containing etching gas;
- forming a blanket layer over the dummy gate stack, and performing an etching of the blanket layer to form spacers located on both sides of the dummy gate stack;
- and
- replacing the dummy gate stack with a gate stack.
7 more elements
A method for forming a FinFET device, comprising:
- patterning a substrate to form fins extending along a first direction;
- forming a dummy gate stack on the substrate and over the fins, wherein forming the dummy gate stack comprises:
- forming a dummy layer having a planar top surface;
- performing an etching step on the dummy layer to form a dummy strip, wherein the etching step only consisting of a first etching step and a second etching step, wherein
- the first etching step is performed on the planar top surface of the dummy layer using a first etching gas to form the dummy strip, wherein the dummy strip has an upper portion with a substantially vertical profile, and a lower portion with separate protruding parts with tapered profiles, and wherein four of the protruding parts are located at corners where the dummy strip intersects with each of the fins;
- and
- the second etching step of the dummy strip is performed to reduce a height and a width of the four of the protruding parts located at the corners where the dummy strip intersects with each of the fins, wherein the second etching step is performed using a second etching gas with a smaller molecular weight of ion as compared to the first etching gas;
- and
- replacing the upper portion and the lower portion with the separate protruding parts of the dummy gate stack with a gate stack.
6 more elements
A method for forming a FinFET device, comprising:
- patterning a substrate to form fins extending along a first direction;
- forming dummy gate stacks on the substrate and over the fins along a second direction perpendicular to the first direction, wherein forming the dummy gate stacks comprises:
- forming a dummy layer;
- performing a first etching step of the dummy layer using a first etching gas to form a first dummy strip and a second dummy strip physically separated from one another, wherein the first dummy strip has a first part that extends along the second direction, and a plurality of tapered second parts located at corners where the first part intersects with the fins, wherein the plurality of tapered second parts is located below a top surface of the fins, the second dummy strip has a third part that extends in parallel with the first part along the second direction, and a plurality of tapered fourth parts located at corners where the third part intersects with the fins, wherein the plurality of tapered fourth parts is located below another top surface of the fins, and the plurality of tapered second parts is facing the plurality of tapered fourth parts and spaced apart from the plurality of tapered fourth parts by a first distance;
- and
- performing a second etching step to reduce a dimension of the plurality of tapered second parts of the first dummy strip, and to reduce a dimension of the plurality of tapered fourth parts of the second dummy strip so that the first distance between the plurality of tapered second parts and the plurality of tapered fourth parts is increased, and wherein the second etching step is performed using a second etching gas with a smaller molecular weight of ion as compared to the first etching gas;
- and
- replacing the dummy gate stacks with gate stacks.
5 more elements
Dependencies are inferred from the claim text.