US 11,688,797 B2Granted

Semiconductor device and forming method thereof

AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.

InventorsHsin-Yi Lee, Cheng-Lung Hung, Chi On Chui

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Abstract

A method of forming a semiconductor device including forming a fin structure having a stack of alternating first semiconductor layers and second semiconductor layers over a substrate, the first semiconductor layers and the second semiconductor layers having different compositions, forming a dummy gate structure across the fin structure, forming gate spacers on opposite sidewalls of the dummy gate structure, respectively, removing the dummy gate structure to form a gate trench between the gate spacers, etching the first semiconductor layers in the gate trench, such that the second semiconductor layers are suspended in the gate trench to serve as nanosheets, forming a work function metal layer surrounding each of the nanosheets, and depositing a fill metal layer over the work function metal layer without using a fluorine-containing precursor.

Claims20

Dependent claims

A method of forming a semiconductor device, comprising:

forming a fin structure having a stack of alternating first semiconductor layers and second semiconductor layers over a substrate, the first semiconductor layers and the second semiconductor layers having different compositions;
forming a dummy gate structure across the fin structure;
forming gate spacers on opposite sidewalls of the dummy gate structure, respectively;
removing the dummy gate structure to form a gate trench between the gate spacers;
etching the first semiconductor layers in the gate trench, such that the second semiconductor layers are suspended in the gate trench to serve as nanosheets;
forming a work function metal layer surrounding each of the nanosheets, wherein the work function metal layer on adjacent nanosheets merges as a single continuous layer, and wherein from a cross-sectional view, each of the nanosheets has arc-shaped sides, and the single continuous layer has repeating arc patterns corresponding to the arc-shaped sides of the nanosheets in a one-to-one manner;
forming a glue layer on the work function metal layer, wherein the glue layer has a thickness less than a thickness of the work function metal layer;
and
depositing a fill metal layer over the work function metal layer without using a fluorine-containing precursor, wherein depositing the fill metal layer comprises:
conformally forming a first fluorine-free metal sublayer over the glue layer, wherein the first fluorine-free metal sublayer comprises TaN,
conformally forming a second fluorine-free metal sublayer over the first fluorine-free metal sublayer, wherein the second fluorine-free metal sublayer comprises TiN or tungsten;
and
forming a third fluorine-free metal sublayer over the second fluorine-free metal sublayer.

10 more elements

A method of forming a semiconductor device, comprising:

forming a fin structure having a stack of alternating first semiconductor layers and second semiconductor layers over a substrate;
forming a dummy gate structure across the fin structure;
forming gate spacers on opposite sidewalls of the dummy gate structure, respectively;
removing the dummy gate structure to form a gate trench between the gate spacers;
etching the first semiconductor layers in the gate trench, such that the second semiconductor layers are suspended in the gate trench to serve as nanosheets;
and
forming a metal gate structure filling up the gate trench, where formation of the metal gate structure comprising:
forming a first work function metal layer surrounding each of the nanosheets, wherein the first work function metal layer on adjacent nanosheets merges as a single continuous layer, and wherein from a cross-sectional view, each of the nanosheets has arc-shaped sides, and the single continuous layer has repeating arc patterns corresponding to the arc-shaped sides of the nanosheets in a one-to-one manner;
forming a glue layer surrounding the first work function metal layer, wherein the glue layer has a thickness less than a thickness of the first work function metal layer;
and
forming a second work function metal layer over the glue layer such that the second work function metal layer fills the gate trench between the gate spacers, wherein the second work function metal layer is an outermost layer of the metal gate structure, the second work function metal layer is fluorine-free, and the second work function metal layer comprises:
a first fluorine-free metal sublayer conformally over the glue layer, wherein the first fluorine-free metal sublayer comprises TaN,
a second fluorine-free metal sublayer conformally over the first fluorine-free metal sublayer, wherein the second fluorine-free metal sublayer comprises TiN or tungsten;
and
a third fluorine-free metal sublayer over the second fluorine-free metal sublayer.

12 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/140,308Filed 4 Jan 2021
Published: US 2022/0216323 A17 Jul 2022
Granted: 27 Jun 2023
Term ends: Not estimatedThe source records don’t support an estimate.

Classification16 codes

H10D 30/0243
Of fin field-effect transistors [FinFET]: using dummy structures having essentially the same shapes as the semiconductor bodies, e.g. to provide…
H10D 30/0191
Of FETs having stacked nanowire, nanosheet or nanoribbon channels: forming stacked channels, e.g. changing their shapes or sizes
H10D 30/503
Characterised by the stacked channels: having non-rectangular cross-sections
H10D 30/6211
Fin field-effect transistors [FinFET]: having fin-shaped semiconductor bodies integral with the bulk semiconductor substrates