# US 2017/0287724 A1 · Selective self-aligned patterning of silicon germanium, germanium and type iii/v materials using a sulfur-containing mask

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- Number: US 2017/0287724 A1
- Document ID: US20170287724A1
- Status: Published application
- Kind: A1
- Application number: 15/377,359
- Filed: 2016-12-13
- Published: 2017-10-05
- Earliest claimed: 2016-03-29
- Assignees: Lam Research Corporation
- Applicants: Lam Research Corporation
- Inventors: Daniel Peter; Samantha Tan; Reza Arghavani; Yang Pan
- Web page: https://patentgrep.com/patent/US20170287724A1

## CPC

- H10P 50/642: {Chemical etching}
- H10P 50/00: Etching of wafers, substrates or parts of devices
- H10P 50/692: {characterised by their composition, e.g. multilayer masks or materials}
- H10P 50/694: {characterised by their behaviour during the process, e.g. soluble masks or redeposited masks}
- H10P 70/20: {Cleaning during device manufacture}
- H10P 50/283: {by chemical means}
- H10P 95/08: {Planarisation of organic insulating materials}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A method for patterning a substrate including multiple layers using a sulfur-based mask includes providing a substrate including a first layer and a second layer arranged on the first layer. The first layer includes a material selected from a group consisting of germanium, silicon germanium and type III/V materials. The method includes depositing a mask layer including sulfur species on sidewalls of the first layer and the second layer by exposing the substrate to a first wet chemistry. The method includes removing the mask layer on the sidewalls of the second layer while not completely removing the mask layer on the sidewalls of the first layer by exposing the substrate to a second wet chemistry. The method includes selectively etching the second layer relative to the first layer and the mask layer on the sidewalls of the first layer by exposing the substrate to a third wet chemistry.

## Claims

### Claim 1

A method for patterning a substrate including multiple layers using a sulfur-based mask, comprising:
a) providing a substrate including a first layer and a second layer arranged on the first layer, wherein the first layer includes a material selected from a group consisting of germanium, silicon germanium and type III/V materials;
b) depositing a mask layer including sulfur species on sidewalls of the first layer and the second layer by exposing the substrate to a first wet chemistry;
c) removing the mask layer on the sidewalls of the second layer while not completely removing the mask layer on the sidewalls of the first layer by exposing the substrate to a second wet chemistry; and
d) selectively etching the second layer relative to the first layer and the mask layer on the sidewalls of the first layer by exposing the substrate to a third wet chemistry.

### Claim 2 (depends on 1)

The method of claim 1, further comprising repeating b), c) and d) one or more times.

### Claim 3 (depends on 1)

The method of claim 1, further comprising:
e) performing a clean process prior to b).

### Claim 4 (depends on 3)

The method of claim 3, wherein the clean process includes exposing the substrate to a mixture including deionized water (DIW), aqueous hydrochloric acid (HCl) and aqueous hydrogen peroxide (H2O2) at a predetermined temperature for a predetermined period.

### Claim 5 (depends on 3)

The method of claim 3, wherein the clean process includes exposing the substrate to dilute hydrofluoric acid (HF).

### Claim 6 (depends on 3)

The method of claim 3, further comprising:
f) enhancing a surface of the substrate by exposing the substrate to a fourth wet chemistry to increase bonding of the mask layer before b).

### Claim 7 (depends on 6)

The method of claim 6, further comprising repeating f), b), c) and d) one or more times.

### Claim 8 (depends on 6)

The method of claim 6, wherein exposing the substrate to the fourth wet chemistry includes exposing the substrate to chemistry selected from a group consisting of dilute hydrogen chloride (HCl), dilute hydrogen bromide (HBr), dilute hydrogen iodide (HI), and combinations thereof.

### Claim 9 (depends on 1)

The method of claim 1, wherein exposing the substrate to the first wet chemistry includes exposing the substrate to chemistry selected from a group including ammonium sulfide (NH4)2S, elemental sulfur (S), alkane-thiols, and combinations thereof.

### Claim 10 (depends on 1)

The method of claim 1, wherein exposing the substrate to the second wet chemistry includes exposing the substrate to chemistry selected from a group including a mixture of hydrofluoric acid (HF) and hydrogen peroxide (H2O2), ammonia (NH3), potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), chlorine, sodium peroxide (Na2O2), sodium hypochlorite (NaClO), ozone (O3), potassium cyanide (KCN), a mixture of potassium hydroxide (KOH), potassium ferricyanide K3Fe(CN)6 and water (H2O), a mixture of hydrofluoric acid and nitric acid (HF/HNO3), a mixture of citric acid and H2O2, a mixture of HF/HNO3/acetic acid (HAc) and silver nitrate (AgNO3), a mixture of HNO3 and tartaric acid, ammonium persulfate, and combinations thereof.

### Claim 11 (depends on 1)

The method of claim 1, wherein exposing the substrate to the third wet chemistry includes exposing the substrate to chemistry selected from a group consisting of hydrogen peroxide (H2O2), a mixture of hydrochloric acid (HCl) and hydrogen peroxide (H2O2), a mixture of HCl and nitric acid (HNO3), HNO3, a mixture of hydrofluoric acid, nitric acid and tartaric acid, a mixture of hydrofluoric acid, nitric acid and acetic acid, and combinations thereof.

### Claim 12 (depends on 1)

The method of claim 1, wherein the second layer includes the material and one or more other materials, and wherein the material is greater than or equal to 50% by weight of the second layer.

### Claim 13 (depends on 1)

The method of claim 1, wherein the first layer includes germanium and the second layer includes silicon germanium.

### Claim 14 (depends on 13)

The method of claim 13, wherein the germanium in the second layer comprises greater than or equal to 50% by weight of the second layer.

### Claim 15 (depends on 1)

The method of claim 1, wherein the first layer includes silicon germanium and the second layer includes silicon.

### Claim 16

A method for patterning a substrate including multiple layers using a sulfur-based mask, comprising:
a) providing a substrate including a first layer and a second layer arranged on the first layer, the first layer including a material selected from a group consisting of germanium, silicon germanium and type III/V materials, the second layer including the material and one or more other materials, and the material is greater than or equal to 50% by weight of the second layer;
b) cleaning the substrate;
c) enhancing a surface of the substrate to increase bonding of a mask layer;
d) depositing the mask layer including a sulfur species onto sidewalls of the first layer and the second layer by exposing the substrate to a first wet chemistry;
e) removing the mask layer on the sidewalls of the second layer while not completely removing the mask layer on the sidewalls of the first layer by exposing the substrate to a second wet chemistry;
f) selectively etching the second layer relative to the first layer by exposing the substrate to a third wet chemistry; and
g) repeating d), e) and f) one or more times.

### Claim 17 (depends on 16)

The method of claim 16, wherein b) includes exposing the substrate to a mixture including deionized water (DIW), aqueous hydrochloric acid (HCl) and aqueous hydrogen peroxide (H2O2) at a predetermined temperature for a predetermined period.

### Claim 18 (depends on 17)

The method of claim 17, wherein b) includes exposing the substrate to dilute hydrofluoric acid (HF).

### Claim 19 (depends on 17)

The method of claim 17, wherein c) includes exposing the substrate to chemistry selected from a group consisting of dilute hydrogen chloride (HCl), dilute hydrogen bromide (HBr), and dilute hydrogen iodide (HI), and combinations thereof.

### Claim 20 (depends on 17)

The method of claim 17, wherein the first wet chemistry is selected from a group including ammonium sulfide (NH4)2S, elemental sulfur (S), alkane-thiols, and combinations thereof.

### Claim 21 (depends on 17)

The method of claim 17, wherein the second wet chemistry is selected from a group including a mixture of hydrofluoric acid (HF) and hydrogen peroxide (H2O2), ammonia (NH3), potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), chlorine, sodium peroxide (Na2O2), sodium hypochlorite (NaClO), ozone (O3), potassium cyanide (KCN), a mixture of potassium hydroxide (KOH), potassium ferricyanide K3Fe(CN)6 and water (H2O), a mixture of hydrofluoric acid and nitric acid (HF/HNO3), a mixture of citric acid and H2O2, a mixture of HF/HNO3/acetic acid (HAc) and silver nitrate (AgNO3), a mixture of HNO3 and tartaric acid, ammonium persulfate, and combinations thereof.

### Claim 22 (depends on 17)

The method of claim 17, wherein the third wet chemistry is selected from a group consisting of hydrogen peroxide (H2O2), a mixture of hydrochloric acid (HCl) and hydrogen peroxide (H2O2), a mixture of HCl and nitric acid (HNO3), HNO3, a mixture of hydrofluoric acid, nitric acid and tartaric acid, a mixture of hydrofluoric acid, a mixture of nitric acid and acetic acid, and combinations thereof.

### Claim 23 (depends on 17)

The method of claim 17, wherein the first layer includes germanium and the second layer includes silicon germanium.

### Claim 24 (depends on 17)

The method of claim 17, wherein the first layer includes silicon germanium and the second layer includes silicon.