Residue removal in metal gate cutting process
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChieh-Ning Feng, Chih-Chang Hung, Bing-Hung Chen, Yih-Ann Lin
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Abstract
A method includes forming a gate dielectric layer, forming a metal gate strip over a bottom portion of the gate dielectric layer, and performing a first etching process on the metal gate strip to remove a portion of the metal gate strip. The first etching process is performed anisotropically. After the first etching process, a second etching process is performed on the metal gate strip to remove a residue portion of the metal gate strip. The second etching process includes an isotropic etching process. A dielectric material is filled into a recess left by the etched portion and the etched residue portion of the metal gate strip.
Claims19
A method comprising:
- forming a gate dielectric layer;
- forming a metal gate strip over a bottom portion of the gate dielectric layer;
- forming a hard mask over the metal gate strip;
- patterning the hard mask;
- performing a first etching process on the metal gate strip to remove a portion of the metal gate strip, wherein the first etching process is performed anisotropically;
- oxidizing the hard mask to form a protection layer on a sidewall of the hard mask;
- after the first etching process, performing a second etching process on the metal gate strip to remove a residue portion of the metal gate strip, wherein the second etching process comprises an isotropic etching process, and wherein the protection layer is exposed to the second etching process;
- and
- filling a dielectric material into a recess left by the etched portion and the etched residue portion of the metal gate strip.
A method comprising:
- forming a gate stack over and contacting a dielectric dummy fin, wherein the gate stack comprises:
- a first portion on a first side of the dielectric dummy fin;
- a second portion on a second side of the dielectric dummy fin;
- a third portion overlapping the gate stack, wherein the third portion interconnects the first portion and the second portion;
- etching the third portion, a first part of the first portion, and a second part of the second portion of the gate stack to reveal a top surface and sidewalls of the dielectric dummy fin, wherein after the etching, a residue portion of the third portion is left, and the residue portion interconnects the first portion and the second portion;
- and
- etching the residue portion.
A method comprising:
- forming a metal gate strip;
- forming an amorphous layer over the metal gate strip;
- forming a patterned hard mask over the amorphous layer;
- etching the amorphous layer using the patterned hard mask as an etching mask, wherein the metal gate strip is revealed;
- etching the metal gate strip to form a recess in the metal gate strip, wherein the recess has a bottom surface lower than a top surface of an underlying dielectric dummy fin, and the top surface and opposite sidewalls of the underlying dielectric dummy fin are exposed to the recess;
- performing a thermal etching process to remove a residue portion of the metal gate strip;
- and
- filling a dielectric material into the recess.
Dependencies are inferred from the claim text.