Patent · US10529585B2 · B2 · US

Dry stripping of boron carbide hardmask

(11) Publication number

US10529585B2

(21) Application number

15/995,698

(22) Filing date

2018-06-01

(30) Priority date

2017-06-02

(43) Publication date

2020-01-07

(45) Date of grant

2020-01-07

(51) IPC

H10P 72/00; H10P 72/30; C23C 16/32; C23C 16/38

(52) CPC

H10P Generic processes or apparatus for the manufacture or treatment of devices covered by class H10: 50/285, 14/6512, 14/6923, 50/283, 50/73, 70/12, 70/23, 72/0402, 72/0432, 72/0434, 72/0462, 72/0602, 72/3311
C23C Coating metallic material; coating material with metallic material; surface treatment of metallic material by diffusion into the surface, by chemical conversion or substitution; coating by vacuum evaporation, by sputtering, by ion implantation or by chemical vapour deposition, in general: 16/32, 16/38
H01L Semiconductor devices; electric solid state devices not otherwise provided for: 21/02046, 21/0206, 21/31116, 21/31122, 21/31144, 21/67017, 21/67103, 21/67109, 21/6719, 21/67248, 21/67754
H10W Generic packages, interconnections, connectors or other constructional details of devices covered by class H10: 20/0526, 20/054

(73) Assignee

Applied Materials Inc

(72) Inventors

Pramit MANNA; Shishi Jiang; Abhijit Basu Mallick; Kurtis LESCHKIES

(54) Title

Dry stripping of boron carbide hardmask

(57) Abstract

Embodiments of the disclosure generally relate to a method for dry stripping a boron carbide layer deposited on a semiconductor substrate. In one embodiment, the method includes loading the substrate with the boron carbide layer into a pressure vessel, exposing the substrate to a processing gas comprising an oxidizer at a pressure between about 500 Torr and 60 bar, heating the pressure vessel to a temperature greater than a condensation point of the processing gas and removing one or more products of a reaction between the processing gas and the boron carbide layer from the pressure vessel.

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Claims (20)

A method of stripping a boron carbide layer deposited on a substrate, the method comprising: loading the substrate into a processing region of a pressure vessel, the substrate having the boron carbide layer deposited thereon; exposing the substrate to a processing gas comprising an oxidizer at a pressure between about 500 Torr and about 60 bar, wherein the processing gas does not comprise a plasma; heating the processing region of the pressure vessel to a temperature greater than a condensation point of the processing gas; and removing one or more products of a reaction between the processing gas and the boron carbide layer from the pressure vessel.
The method of claim 1 wherein exposing the substrate to a processing gas comprises: exposing the substrate to steam at a pressure greater than about 10 bar.
The method of claim 2, wherein the substrate is exposed to an amount of steam at least ten times an amount of boron carbide deposited on the substrate.
The method of claim 1, wherein the oxidizer is selected from a group consisting of ozone, oxygen, water vapor, heavy water, ammonia, a peroxide, a hydroxide-containing compound, oxygen isotopes and hydrogen isotopes.
The method of claim 4, wherein the oxidizer is hydrogen peroxide.
The method of claim 1, wherein the substrate ape is exposed to an amount of oxidizer in excess of an amount of oxidizer required to completely react with an amount of boron carbide deposited on the substrate.
The method of claim 1, wherein the processing region of the pressure vessel is heated to a temperature between about 300 degrees Celsius and about 700 degrees Celsius.
The method of claim 1, wherein the processing gas comprises about 5% dry steam to about 100% dry steam.
The method of claim 1, wherein the one or more products of the reaction comprise: boron trioxide, carbon dioxide, carbon monoxide, hydrogen, boric acid and metaboric acid.
A method of stripping a boron carbide layer deposited on a plurality of substrates, the method comprising: loading the plurality of substrates simultaneously into a processing region of a pressure vessel, the plurality of substrates each having the boron carbide layer deposited thereon; exposing the plurality of substrates to a processing gas comprising an oxidizer at a pressure between about 500 Torr and about 60 bar; heating the processing region of the pressure vessel to a temperature greater than a condensation point of the processing gas; and removing one or more products of a reaction between the processing gas and the boron carbide layer from the pressure vessel.
The method of claim 10, wherein exposing the plurality of substrates to the processing gas comprises: exposing the plurality of substrates to steam at a pressure greater than about 10 bar.
The method of claim 11, wherein the plurality of substrates are exposed to an amount of steam at least ten times an amount of boron carbide deposited on the plurality of substrates.
The method of claim 10, wherein the oxidizer is selected from a group consisting of ozone, oxygen, water vapor, heavy water, ammonia, a peroxide, a hydroxide-containing compound, oxygen isotopes and hydrogen isotopes.
The method of claim 13, wherein the oxidizer is hydrogen peroxide.
The method of claim 10, wherein the plurality of substrates are exposed to an amount of oxidizer in excess of an amount of oxidizer required to completely react with an amount of boron carbide deposited on the plurality of substrates.
The method of claim 10, wherein the processing region of the pressure vessel is heated to a temperature between about 300 degrees Celsius and about 700 degrees Celsius.
The method of claim 10, wherein the processing gas comprises about 5% dry steam to about 100% dry steam.
The method of claim 10, wherein the one or more products of the reaction comprise: boron trioxide, carbon dioxide, carbon monoxide, hydrogen, boric acid and metaboric acid.
A method of stripping a boron carbide layer deposited on a plurality of substrates, the method comprising: loading the plurality of substrates simultaneously into a processing region of a pressure vessel, the plurality of substrates each having the boron carbide layer deposited thereon; exposing the plurality of substrates to a processing gas comprising steam at a pressure between about 10 bar and about 60 bar; heating the processing region of the pressure vessel to a temperature greater than a condensation point of the processing gas; and removing one or more products of a reaction between the processing gas and the boron carbide layer from the pressure vessel.
The method of claim 19, wherein the processing gas comprises about 5% superheated steam to about 100% superheated steam.

Description

Embodiments of the disclosure generally relate to fabrication of integrated circuits and particularly to a method of dry stripping a boron carbide layer on a semiconductor substrate.

Formation of a semiconductor device, such as memory devices, logic devices, microprocessors, etc., involves formation of a hardmask. A hardmask is formed as a blanket layer on an underlying substrate to be etched. A patterned layer of photo-resist is formed over the hardmask before the hardmask is etched using the photo-resist layer as a pattern. After patterning the hardmask, the photo-resist layer is removed such that the hardmask remains the sole pattern for etching the underlying substrate. While a hardmask is a separate layer formed on the underlying substrate, etched, and then removed from the substrate, improved resistance to the process of etching as well as reduced costs make hardmasks desirable. Films of boron-doped carbon and boron carbide are commonly known to produce high-quality hardmask due to superior patterning performance.

However, boron carbide layers are difficult to remove or strip from the underlying substrate after etching since boron carbide layers cannot be ashed using a conventional oxygen plasma. Boron carbide layers can be dry stripped using fluorine or chlorine along with oxygen; however, fluorine and chlorine are corrosive to dielectric materials such as silicon oxide, silicon nitride, and silicon oxynitride commonly found on semiconductor substrates. A wet-etch solution, if used, can also damage exposed metal surfaces or embedded metals commonly found on semiconductor substrates.

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Record as JSON

{
  "publication_number": "US10529585B2",
  "country": "US",
  "kind": "B2",
  "title": "Dry stripping of boron carbide hardmask",
  "abstract": "Embodiments of the disclosure generally relate to a method for dry stripping a boron carbide layer deposited on a semiconductor substrate. In one embodiment, the method includes loading the substrate with the boron carbide layer into a pressure vessel, exposing the substrate to a processing gas comprising an oxidizer at a pressure between about 500 Torr and 60 bar, heating the pressure vessel to a temperature greater than a condensation point of the processing gas and removing one or more products of a reaction between the processing gas and the boron carbide layer from the pressure vessel.",
  "claims": [
    "1. A method of stripping a boron carbide layer deposited on a substrate, the method comprising: loading the substrate into a processing region of a pressure vessel, the substrate having the boron carbide layer deposited thereon; exposing the substrate to a processing gas comprising an oxidizer at a pressure between about 500 Torr and about 60 bar, wherein the processing gas does not comprise a plasma; heating the processing region of the pressure vessel to a temperature greater than a condensation point of the processing gas; and removing one or more products of a reaction between the processing gas and the boron carbide layer from the pressure vessel.",
    "2. The method of claim 1 wherein exposing the substrate to a processing gas comprises: exposing the substrate to steam at a pressure greater than about 10 bar.",
    "3. The method of claim 2, wherein the substrate is exposed to an amount of steam at least ten times an amount of boron carbide deposited on the substrate.",
    "4. The method of claim 1, wherein the oxidizer is selected from a group consisting of ozone, oxygen, water vapor, heavy water, ammonia, a peroxide, a hydroxide-containing compound, oxygen isotopes and hydrogen isotopes.",
    "5. The method of claim 4, wherein the oxidizer is hydrogen peroxide.",
    "6. The method of claim 1, wherein the substrate ape is exposed to an amount of oxidizer in excess of an amount of oxidizer required to completely react with an amount of boron carbide deposited on the substrate.",
    "7. The method of claim 1, wherein the processing region of the pressure vessel is heated to a temperature between about 300 degrees Celsius and about 700 degrees Celsius.",
    "8. The method of claim 1, wherein the processing gas comprises about 5% dry steam to about 100% dry steam.",
    "9. The method of claim 1, wherein the one or more products of the reaction comprise: boron trioxide, carbon dioxide, carbon monoxide, hydrogen, boric acid and metaboric acid.",
    "10. A method of stripping a boron carbide layer deposited on a plurality of substrates, the method comprising: loading the plurality of substrates simultaneously into a processing region of a pressure vessel, the plurality of substrates each having the boron carbide layer deposited thereon; exposing the plurality of substrates to a processing gas comprising an oxidizer at a pressure between about 500 Torr and about 60 bar; heating the processing region of the pressure vessel to a temperature greater than a condensation point of the processing gas; and removing one or more products of a reaction between the processing gas and the boron carbide layer from the pressure vessel.",
    "11. The method of claim 10, wherein exposing the plurality of substrates to the processing gas comprises: exposing the plurality of substrates to steam at a pressure greater than about 10 bar.",
    "12. The method of claim 11, wherein the plurality of substrates are exposed to an amount of steam at least ten times an amount of boron carbide deposited on the plurality of substrates.",
    "13. The method of claim 10, wherein the oxidizer is selected from a group consisting of ozone, oxygen, water vapor, heavy water, ammonia, a peroxide, a hydroxide-containing compound, oxygen isotopes and hydrogen isotopes.",
    "14. The method of claim 13, wherein the oxidizer is hydrogen peroxide.",
    "15. The method of claim 10, wherein the plurality of substrates are exposed to an amount of oxidizer in excess of an amount of oxidizer required to completely react with an amount of boron carbide deposited on the plurality of substrates.",
    "16. The method of claim 10, wherein the processing region of the pressure vessel is heated to a temperature between about 300 degrees Celsius and about 700 degrees Celsius.",
    "17. The method of claim 10, wherein the processing gas comprises about 5% dry steam to about 100% dry steam.",
    "18. The method of claim 10, wherein the one or more products of the reaction comprise: boron trioxide, carbon dioxide, carbon monoxide, hydrogen, boric acid and metaboric acid.",
    "19. A method of stripping a boron carbide layer deposited on a plurality of substrates, the method comprising: loading the plurality of substrates simultaneously into a processing region of a pressure vessel, the plurality of substrates each having the boron carbide layer deposited thereon; exposing the plurality of substrates to a processing gas comprising steam at a pressure between about 10 bar and about 60 bar; heating the processing region of the pressure vessel to a temperature greater than a condensation point of the processing gas; and removing one or more products of a reaction between the processing gas and the boron carbide layer from the pressure vessel.",
    "20. The method of claim 19, wherein the processing gas comprises about 5% superheated steam to about 100% superheated steam."
  ],
  "description_excerpt": "Embodiments of the disclosure generally relate to fabrication of integrated circuits and particularly to a method of dry stripping a boron carbide layer on a semiconductor substrate.\n\nFormation of a semiconductor device, such as memory devices, logic devices, microprocessors, etc., involves formation of a hardmask. A hardmask is formed as a blanket layer on an underlying substrate to be etched. A patterned layer of photo-resist is formed over the hardmask before the hardmask is etched using the photo-resist layer as a pattern. After patterning the hardmask, the photo-resist layer is removed such that the hardmask remains the sole pattern for etching the underlying substrate. While a hardmask is a separate layer formed on the underlying substrate, etched, and then removed from the substrate, improved resistance to the process of etching as well as reduced costs make hardmasks desirable. Films of boron-doped carbon and boron carbide are commonly known to produce high-quality hardmask due to superior patterning performance.\n\nHowever, boron carbide layers are difficult to remove or strip from the underlying substrate after etching since boron carbide layers cannot be ashed using a conventional oxygen plasma. Boron carbide layers can be dry stripped using fluorine or chlorine along with oxygen; however, fluorine and chlorine are corrosive to dielectric materials such as silicon oxide, silicon nitride, and silicon oxynitride commonly found on semiconductor substrates. A wet-etch solution, if used, can also damage exposed metal surfaces or embedded metals commonly found on semiconductor substrates.",
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  "assignees": [
    "Applied Materials Inc"
  ],
  "inventors": [
    "Pramit MANNA",
    "Shishi Jiang",
    "Abhijit Basu Mallick",
    "Kurtis LESCHKIES"
  ],
  "filing_date": "2018-06-01",
  "publication_date": "2020-01-07",
  "grant_date": "2020-01-07",
  "priority_date": "2017-06-02",
  "application_number": "US-201815995698-A",
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    "US10083834B2",
    "US20180261480A1"
  ]
}

Record 2,364 of 8,000 in Patents full text (MLC-0201). Request the full dataset.