# US 10,770,288 B2 · Selective capping processes and structures formed thereby

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- Number: US 10,770,288 B2
- Document ID: US10770288B2
- Status: Granted
- Kind: B2
- Application number: 16/206,192
- Filed: 2018-11-30
- Published: 2019-05-30
- Granted: 2020-09-08
- Earliest claimed: 2017-11-28
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Chih-Chien Chi; Pei-Hsuan Lee; Hung-Wen Su; Hsiao-Kuan Wei; Jui-Fen Chien; Hsin-Yun Hsu
- Web page: https://patentgrep.com/patent/US10770288B2

## CPC

- H10P 95/00: Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass
- H10D 30/024: {of fin field-effect transistors [FinFET]}
- H10D 30/62: Fin field-effect transistors [FinFET]
- H10D 30/6219: {characterised by the source or drain electrodes}
- H10D 62/021: {Forming source or drain recesses by etching e.g. recessing by etching and then refilling}
- H10D 64/01318: {the conductor comprising a layer of alloy material, compound material or organic material contacting the insulator, e.g. TiN (comprising a layer of alloys of Si, Ge or C H10D64/01314)}
- H10D 64/01342: {by deposition, e.g. evaporation, ALD or laser deposition (H10D64/01344 takes precedence)}
- H10D 64/017: {using dummy gates in processes wherein at least parts of the final gates are self-aligned to the dummy gates, i.e. replacement gate processes}
- H10D 64/519: {characterised by their top-view geometrical layouts}
- H10D 64/668: {the layer being a silicide, e.g. TiSi2}
- H10D 84/853: {comprising FinFETs}
- H10P 14/271: {characterised by the preparation of substrate for selective deposition}
- H10P 14/412: {Deposition of metallic or metal-silicide materials}
- H10P 14/6548: {by forming intermediate materials, e.g. capping layers or diffusion barriers}
- H10P 90/1912: {using selective deposition, e.g. epitaxial lateral overgrowth [ELO] or selective deposition of single crystal silicon}
- H10P 95/904: {of Group III-V semiconductors}
- H10W 10/181: {Semiconductor-on-insulator [SOI] isolation regions, e.g. buried oxide regions of SOI wafers}
- H10W 20/01: {Manufacture or treatment}
- H10W 10/014: {using trench refilling with dielectric materials, e.g. shallow trench isolations}
- H10W 10/17: formed using trench refilling with dielectric materials, e.g. shallow trench isolations
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

Embodiments disclosed herein relate generally to capping processes and structures formed thereby. In an embodiment, a conductive feature, formed in a dielectric layer, has a metallic surface, and the dielectric layer has a dielectric surface. The dielectric surface is modified to be hydrophobic by performing a surface modification treatment. After modifying the dielectric surface, a capping layer is formed on the metallic surface by performing a selective deposition process. In another embodiment, a surface of a gate structure is exposed through a dielectric layer. A capping layer is formed on the surface of the gate structure by performing a selective deposition process.

## Claims

### Claim 1

A structure comprising:
a first dielectric layer over a substrate, the first dielectric layer having a dielectric surface terminated with a species comprising a hydrophobic functional group, wherein the hydrophobic functional group is in a monolayer of hydrophobic functional groups along a top surface of the first dielectric layer;
a conductive feature in the first dielectric layer;
a metal cap on the conductive feature, wherein the metal cap comprises a fluorine free tungsten; and
a second dielectric layer on the dielectric surface and the metal cap.

### Claim 2 (depends on 1)

The structure of claim 1, wherein a surface of the conductive feature, on which the metal cap is disposed, is level with the dielectric surface.

### Claim 3 (depends on 1)

The structure of claim 1, wherein the hydrophobic functional group is a hydrocarbon.

### Claim 4 (depends on 1)

The structure of claim 1, wherein the hydrophobic functional group has a general form of —CXH2X+1.

### Claim 5 (depends on 1)

The structure of claim 1, wherein the metal cap has a thickness of between about 30 Å to about 50 Å.

### Claim 6 (depends on 1)

The structure of claim 1, wherein the metal cap comprises tungsten.

### Claim 7 (depends on 1)

The structure of claim 1, wherein the conductive feature is recessed from a surface of the first dielectric layer.

### Claim 8 (depends on 1)

The structure of claim 1, wherein the metal cap comprises cobalt.

### Claim 9

A structure comprising:
a gate structure over an active area on a substrate;
a first dielectric layer over the substrate and along the gate structure;
a monolayer of hydrophobic functional groups along a top surface of the first dielectric layer;
a metal cap on the gate structure, wherein the metal cap has a concentration of chlorine that is less than 1%;
a second dielectric layer over the metal cap and the first dielectric layer; and
a conductive feature through the second dielectric layer to the metal cap.

### Claim 10 (depends on 9)

The structure of claim 9, wherein the metal cap comprises tungsten.

### Claim 11 (depends on 9)

The structure of claim 9, wherein the metal cap has a thickness in a range from 30 Å to 50 Å.

### Claim 12 (depends on 9)

The structure of claim 9, wherein a bottom surface of the metal cap is level with a top surface of the first dielectric layer.

### Claim 13 (depends on 9)

The structure of claim 9, wherein the gate structure comprises:
a gate dielectric layer having a first horizontal portion, a first vertical portion, and a second vertical portion;
a work-function tuning layer having a second horizontal portion, a third vertical portion, and a fourth vertical portion, the second horizontal portion of the work-function tuning layer being over the first horizontal portion of the gate dielectric layer, the third vertical portion and the fourth vertical portion of the work-function tuning layer being disposed laterally between the first vertical portion and the second vertical portion of the gate dielectric layer; and
a gate electrode disposed laterally between the third vertical portion and the fourth vertical portion of the work-function tuning layer, wherein the metal cap is on top surfaces of the gate electrode and the third vertical portion and the fourth vertical portion of the work-function tuning layer.

### Claim 14 (depends on 9)

The structure of claim 9, wherein at least one of the hydrophobic functional groups has a general form of —CXH2X+1.

### Claim 15 (depends on 9)

The structure of claim 9, wherein the metal cap extends away from the substrate further than the monolayer of the hydrophobic functional groups.

### Claim 16

A structure comprising:
a semiconductor fin;
a gate structure over the semiconductor fin;
spacers adjacent to the gate structure;
an interlayer dielectric adjacent to the spacers, wherein the interlayer dielectric is planar with the spacers at a first surface;
a monolayer of a hydrophobic functional group extending along the first surface from over the interlayer dielectric to over the spacers; and
a capping layer in physical contact with the gate structure, the capping layer being in physical contact with a sidewall of the monolayer of the hydrophobic functional group, wherein the capping layer comprises a fluorine free tungsten.

### Claim 17 (depends on 16)

The structure of claim 16, wherein the hydrophobic functional group has a general form of —CXH2X+1.

### Claim 18 (depends on 16)

The structure of claim 16, wherein the capping layer has a thickness of between about 30 Å to about 50 Å.

### Claim 19 (depends on 16)

The structure of claim 16, wherein the capping layer has a concentration of chlorine that is less than 1%.

### Claim 20 (depends on 16)

The structure of claim 16, wherein the capping layer comprises cobalt.