# US 2021/0242089 A1 · Localized etch stop layer

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- Number: US 2021/0242089 A1
- Document ID: US20210242089A1
- Status: Published application
- Kind: A1
- Application number: 16/781,078
- Filed: 2020-02-04
- Published: 2021-08-05
- Earliest claimed: 2020-02-04
- Assignees: Tokyo Electron Limited
- Applicants: Tokyo Electron Limited
- Inventors: Yun Han; Andrew Metz; Xinghua Sun; David L. O'Meara; Kandabara Tapily; Henan Zhang; Shan Hu
- Web page: https://patentgrep.com/patent/US20210242089A1

## CPC

- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10D 30/024: {of fin field-effect transistors [FinFET]}
- H10D 30/6219: {characterised by the source or drain electrodes}
- 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 84/013: {Manufacturing their source or drain regions, e.g. silicided source or drain regions}
- H10D 84/0149: {Manufacturing their interconnections or electrodes, e.g. source or drain electrodes}
- H10D 84/0158: {the components including FinFETs}
- H10D 84/834: {comprising FinFETs}
- H10P 14/6339: {deposition by cyclic CVD, e.g. ALD, ALE or pulsed CVD}
- H10P 14/683: {carbon-based polymeric organic materials, e.g. polyimides, poly cyclobutene or PVC}
- H10P 50/287: {by chemical means}
- H10W 20/069: {by forming self-aligned vias or self-aligned contact plugs}
- H10D 30/797: {being in source or drain regions, e.g. SiGe source or drain}
- H10D 62/822: comprising only Group IV materials heterojunctions, e.g. Si/Ge heterojunctions
- H10W 20/0765: {the thin functional dielectric layers being temporary, e.g. sacrificial layers}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

In one embodiment, a method includes providing a substrate comprising a source/drain contact region and a dummy gate, forming a first etch stop layer aligned to the source/drain contact region, where the first etch stop layer does not cover the dummy gate. The method may include forming a second etch stop layer over the first etch stop layer, the second etch stop layer covering the first etch stop layer and the dummy gate. The method may include converting the dummy gate to a metal gate. The method may include removing the second etch stop layer using a plasma etching process. The method may include removing the first etch stop layer.

## Claims

### Claim 1

A method comprising:
providing a substrate comprising a source/drain contact region and a dummy gate;
forming a first etch stop layer aligned to the source/drain contact region, the first etch stop layer not covering the dummy gate;
forming a second etch stop layer over the first etch stop layer, the second etch stop layer covering the first etch stop layer and the dummy gate;
converting the dummy gate to a metal gate;
removing the second etch stop layer using a plasma etching process; and
removing the first etch stop layer.

### Claim 2 (depends on 1)

The method of claim 1, wherein forming the first etch stop layer comprises selectively depositing the first etch stop layer only over the source/drain contact region without depositing over the dummy gate.

### Claim 3 (depends on 1)

The method of claim 1, wherein forming the first etch stop layer comprises using an etch back process.

### Claim 4 (depends on 3)

The method of claim 3, wherein forming the first etch stop layer using an etch back process comprises:
depositing a conformal layer using an atomic layer deposition process;
depositing an organic fill over the conformal layer;
using an etch back process, removing portions of the organic fill to expose portions of the conformal layer;
removing the exposed conformal layer; and
removing the remaining portions of the organic fill.

### Claim 5 (depends on 1)

The method of claim 1, wherein the first etch stop layer comprises a metal, and wherein the second etch layer comprises silicon.

### Claim 6 (depends on 1)

The method of claim 1, wherein the first etch stop layer comprises aluminum oxide, titanium oxide, aluminum nitride, or titanium nitride, and wherein the second etch layer comprises silicon nitride.

### Claim 7 (depends on 1)

The method of claim 1, further comprising depositing a metal to physically contact the source/drain contact region.

### Claim 8 (depends on 1)

The method of claim 1, wherein removing the first etch stop layer comprises using a wet etch chemistry.

### Claim 9

A method comprising:
providing a plurality of fins over a substrate and a plurality of dummy gates over the plurality of fins;
forming epitaxial regions over each of the plurality of fins, the epitaxial regions extending between adjacent ones of the plurality of dummy gates;
forming localized etch stop regions covering the epitaxial regions, the localized etch stop regions being formed locally only over the epitaxial regions without covering the plurality of dummy gates;
depositing a global etch stop layer over the substrate, the global etch stop layer covering the plurality of dummy gates and the localized etch stop regions;
depositing an insulating material over the global etch stop layer;
converting the plurality of dummy gates to a plurality of metal gates;
using a contact opening mask, removing an underlying portion of the insulating material to expose an underlying portion of the global etch stop layer;
removing the underlying portion of the global etch stop layer by a plasma etch process; and
removing the localized etch stop regions.

### Claim 10 (depends on 9)

The method of claim 9, wherein forming the localized etch stop regions comprises selectively depositing the localized etch stop regions only over the epitaxial regions without covering the plurality of dummy gates.

### Claim 11 (depends on 9)

The method of claim 9, wherein forming the localized etch stop regions comprises using an etch back process.

### Claim 12 (depends on 11)

The method of claim 11, wherein forming the localized etch stop regions using an etch back process comprises depositing a conformal layer using an atomic layer deposition process;
depositing an organic fill over the conformal layer;
using an etch back process, removing portions of the organic fill to expose portions of the conformal layer;
removing the exposed conformal layer; and
removing the remaining portions of the organic fill.

### Claim 13 (depends on 9)

The method of claim 9, wherein the localized etch stop regions comprise a metal, and wherein the global etch stop layer comprises silicon.

### Claim 14 (depends on 9)

The method of claim 9, wherein the localized etch stop regions comprise aluminum oxide, titanium oxide, aluminum nitride, or titanium nitride, and wherein the global etch stop layer comprises silicon nitride.

### Claim 15 (depends on 9)

The method of claim 9, further comprising depositing a metal to physically contact with contact areas of the epitaxial regions.

### Claim 16 (depends on 9)

The method of claim 9, wherein removing the localized etch stop regions comprises using a wet etch chemistry.

### Claim 17

A semiconductor device comprising:
a fin disposed over a semiconductor substrate;
an isolation region disposed proximate to the fin;
a metal gate disposed over the fin;
a raised source/drain region disposed over the fin, the top surface comprising a contact area and remaining area;
a metal based etch stop layer disposed over the raised source/drain region, the metal based etch stop layer covering substantially all of the remaining area of the top surface of the raised source/drain region; and
a nitride etch stop layer disposed over the metal based etch stop layer and the isolation region, the nitride etch stop layer contacting the isolation region and separated from the remaining area of the top surface by the metal based etch stop layer.

### Claim 18 (depends on 17)

The device of claim 17, wherein the nitride etch stop layer is disposed along sidewalls of the metal gate.

### Claim 19 (depends on 17)

The device of claim 17, wherein the metal based etch stop layer comprises aluminum oxide, titanium oxide, aluminum nitride, or titanium nitride, and wherein the nitride etch stop layer comprises silicon nitride.

### Claim 20 (depends on 17)

The device of claim 17, further comprising a contact plug contacting the contact area of the raised source/drain region.