# US 12,015,068 B2 · Gate structure and method of fabricating the same

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- Number: US 12,015,068 B2
- Document ID: US12015068B2
- Status: Granted
- Kind: B2
- Application number: 17/713,168
- Filed: 2022-04-04
- Published: 2022-07-21
- Granted: 2024-06-18
- Earliest claimed: 2015-11-30
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company Limited
- Inventors: Bo-Wen Hsieh; Yi-Chun Lo; Wen-Jia Hsieh
- Web page: https://patentgrep.com/patent/US12015068B2

## CPC

- H10D 64/518: {characterised by their lengths or sectional shapes}
- H10D 30/022: {having lightly-doped source or drain extensions selectively formed at the sides of the gates}
- H10D 30/0227: {having both lightly-doped source and drain extensions and source and drain regions self-aligned to the sides of the gate, e.g. lightly-doped drain [LDD] MOSFET or double-diffused drain [DDD] MOSFET}
- 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 64/017: {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 64/667: {the conductor comprising a layer of alloy material, compound material or organic material contacting the insulator, e.g. TiN workfunction layers (having lateral variation H10D64/671)}
- H10D 64/669: {the conductor further comprising additional layers of alloy material, compound material or organic material, e.g. TaN/TiAlN}
- H10P 50/667: {by liquid etching only}
- H10P 50/71: {using masks for conductive or resistive materials}
- H10P 76/2043: {using an anti-reflective coating}
- H10D 64/685: {being perpendicular to the channel plane}
- H10D 64/691: {comprising metallic compounds, e.g. metal oxides or metal silicates (insulators comprising nitrogen H10D64/693)}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A gate structure includes at least one spacer defining a gate region over a semiconductor substrate, a gate dielectric layer disposed on the gate region over the semiconductor substrate, a first work function metal layer disposed over the gate dielectric layer and lining a bottom surface of an inner sidewall of the spacer, and a filling metal partially wrapped by the first work function metal layer. The filling metal includes a first portion and a second portion, wherein the first portion is between the second portion and the semiconductor substrate, and the second portion is wider than the first portion.

## Claims

### Claim 1

A gate structure, comprising:
a first dielectric element;
a second dielectric element; and
a filling metal disposed between the first dielectric element and the second dielectric element, wherein:
in a first portion of the filling metal, a width of the filling metal decreases at a first rate moving toward a bottom surface of the filling metal,
in a second portion of the filling metal, the width of the filling metal decreases at a second rate moving toward the bottom surface of the filling metal,
the second rate is less than the first rate,
the second portion of the filling metal is under the first portion of the filling metal,
in a third portion of the filling metal between the first portion of the filling metal and the second portion of the filling metal, the width of the filling metal decreases at a third rate moving toward the bottom surface of the filling metal, and
the third rate is greater than the first rate and the second rate.

### Claim 2 (depends on 1)

The gate structure of claim 1, wherein:
in a fourth portion of the filling metal, the width of the filling metal decreases at a fourth rate moving toward the bottom surface of the filling metal,
the fourth rate is less than the second rate, and
the fourth portion of the filling metal is under the second portion of the filling metal.

### Claim 3 (depends on 1)

The gate structure of claim 1, comprising:
a protection layer extending between the first dielectric element and the second dielectric element and overlying the filling metal.

### Claim 4 (depends on 1)

The gate structure of claim 1, comprising:
a first work function metal layer disposed between the first dielectric element and the filling metal to separate the first dielectric element from the filling metal.

### Claim 5 (depends on 4)

The gate structure of claim 4, comprising:
a protection layer overlying the filling metal, wherein the protection layer is in contact with a sidewall of the first dielectric element and a top surface of the first work function metal layer.

### Claim 6 (depends on 4)

The gate structure of claim 4, comprising:
a second work function metal layer disposed between the first work function metal layer and the filling metal, wherein:
the first portion of the filling metal is in contact with the first work function metal layer, and
the second portion of the filling metal is in contact with the second work function metal layer.

### Claim 7 (depends on 1)

The gate structure of claim 1, comprising:
a first work function metal layer disposed between the first dielectric element and the filling metal;
a second work function metal layer disposed between the first work function metal layer and the filling metal; and
a third work function metal layer disposed between the second work function metal layer and the filling metal.

### Claim 8 (depends on 7)

The gate structure of claim 7, wherein the filling metal contacts the first work function metal layer.

### Claim 9 (depends on 7)

The gate structure of claim 7, comprising a protection layer spaced apart from the third work function metal layer by the filling metal.

### Claim 10 (depends on 9)

The gate structure of claim 9, wherein the protection layer contacts the first work function metal layer.

### Claim 11

A gate structure, comprising:
a first dielectric element;
a second dielectric element;
a filling metal disposed between the first dielectric element and the second dielectric element;
a first work function metal layer disposed between the first dielectric element and the filling metal; and
a second work function metal layer, wherein:
the first work function metal layer is present between a first portion of the second work function metal layer and the first dielectric element,
the first work function metal layer is not present between a second portion of the second work function metal layer and the first dielectric element,
the first work function metal layer, the first portion of the second work function metal layer, and the filling metal are laterally coincident such that a plane extending parallel to a top surface of the filling metal intersects each of the first work function metal layer, the first portion of the second work function metal layer, and the filling metal,
in a first portion of the filling metal, a width of the filling metal decreases at a first rate moving toward a bottom surface of the filling metal,
in a second portion of the filling metal, the width of the filling metal decreases at a second rate moving toward the bottom surface of the filling metal,
the second rate is less than the first rate,
the second portion of the filling metal is under the first portion of the filling metal,
in a third portion of the filling metal between the first portion of the filling metal and the second portion of the filling metal, the width of the filling metal decreases at a third rate moving toward the bottom surface of the filling metal, and
the third rate is greater than the first rate and the second rate.

### Claim 12 (depends on 11)

The gate structure of claim 11, wherein the second portion of the second work function metal layer is above the first portion of the second work function metal layer.

### Claim 13 (depends on 11)

The gate structure of claim 11, wherein the second work function metal layer is between an uppermost surface of the first work function metal layer and the filling metal.

### Claim 14 (depends on 11)

The gate structure of claim 11, comprising:
a third work function metal layer between the first dielectric element and the first work function metal layer.

### Claim 15 (depends on 14)

The gate structure of claim 14, wherein the second work function metal layer contacts the third work function metal layer.

### Claim 16 (depends on 11)

The gate structure of claim 11, comprising a protection layer overlying the filling metal and disposed between the first dielectric element and the second dielectric element.

### Claim 17

A gate structure, comprising:
a first dielectric element;
a second dielectric element;
a filling metal disposed between the first dielectric element and the second dielectric element, wherein:
in a first portion of the filling metal, a width of the filling metal decreases at a first rate moving toward a bottom surface of the filling metal,
in a second portion of the filling metal, the width of the filling metal decreases at a second rate moving toward the bottom surface of the filling metal,
the second rate is less than the first rate, and
the second portion of the filling metal is under the first portion of the filling metal;
a first work function metal layer disposed between the first dielectric element and the filling metal;
a second work function metal layer disposed between the first work function metal layer and the filling metal;
a third work function metal layer disposed between the second work function metal layer and the filling metal; and
a protection layer spaced apart from the third work function metal layer by the filling metal.

### Claim 18 (depends on 17)

The gate structure of claim 17, wherein the protection layer contacts the first work function metal layer.

### Claim 19 (depends on 17)

The gate structure of claim 17, wherein the filling metal contacts the first work function metal layer.

### Claim 20 (depends on 17)

The gate structure of claim 17, wherein the second work function metal layer is spaced apart from the filling metal by the third work function metal layer such that the second work function metal layer does not contact the filling metal.