Low temperature plasma deposition process for carbon layer deposition

• US 20060264060A1
• Filed: 05/17/2005
• Published: 11/23/2006
• Est. Priority Date: 05/17/2005
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Ramaswamy, Kartik, Mayur, Abhilash J., Hanawa, Hiroji, Collins, Kenneth S., Nguyen, Andrew, Al-Bayati, Amir, Parihar, Vijay, Jennings, Dean, Gallo, Biagio, Ma, Kai
• Granted Patent: US 7,312,162 B2
• Time in Patent Office: Days
• US Class Current: 438/758
• CPC Class Codes: C23C 16/26 Deposition of carbon only
• CPC Class Codes: C23C 16/505 using radio frequency discharges
• CPC Class Codes: C23C 16/52 Controlling or regulating the coating process C23C16/45557, C23C16/279 take precedence
• CPC Class Codes: H01L 21/02115 the material being carbon, e.g. alpha-C, diamond or hydrogen doped carbon
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/268 using electromagnetic radiation, e.g. laser radiation
• CPC Class Codes: H01L 21/3146 Carbon layers, e.g. diamond-like layers

Abstract

A method of depositing a carbon layer on a workpiece includes placing the workpiece in a reactor chamber, introducing a carbon-containing process gas into the chamber, generating a reentrant toroidal RF plasma current in a reentrant path that includes a process zone overlying the workpiece by coupling plasma RF source power to an external portion of the reentrant path, and coupling RF plasma bias power or bias voltage to the workpiece.

Claims

1. A method of depositing a carbon layer on a workpiece, comprising:

placing the workpiece in a reactor chamber;

introducing a carbon-containing process gas into the chamber;

generating a reentrant toroidal RF plasma current in a reentrant path that includes a process zone overlying the workpiece by coupling plasma RF source power to an external portion of said reentrant path; and

coupling RF plasma bias power or bias voltage to the workpiece.

2. The method of claim 1 wherein the step of introducing the carbon-containing process gas comprises introducing the process gas through a gas distribution plate overlying the workpiece and underlying the external portion of the reentrant path.

3. The method of claim 1 wherein said process gas comprises a hydrogen-carbon chemical species.

4. The method of claim 1 further comprising setting conductivity of the carbon layer between insulative and semiconductive by at least one of:

(1) adjusting the ion bombardment energy at the wafer surface,

(2) adjusting the workpiece temperature,

(3) selecting the hydrogen-carbon gas species of the process gas in accordance with a hydrogen-carbon ratio of the gas,

(4) diluting the process gas with hydrogen,

(5) diluting the process gas with an inert gas such as helium, neon, argon or xenon,

(6) adjusting the flux of energetic ions at the wafer surface relative to the flux of carbon-containing radical species to the wafer surface,

(7) adding to the process gas a precursor additive gas of one of;

(a) a semi-conductivity-enhancing species, (b) a resistivity-enhancing species;

(8) implanting in the deposited carbon layer one of;

(a) a semiconductivity-enhancing species, (b) a resistivity-enhancing species.

5. The method of claim 1 further comprising setting the transparency or opacity of the carbon layer by at least one of:

(1) adjusting the ion bombardment energy at the wafer surface,

(2) adjusting the workpiece temperature,

(3) selecting the hydrogen-carbon gas species of the process gas in accordance with a hydrogen-carbon ratio of the gas,

(4) diluting the process gas with hydrogen,

(5) diluting the process gas with an inert gas such as helium, neon, argon or xenon,

(6) adjusting the flux of energetic ions at the wafer surface relative to the flux of carbon-containing radical species to the wafer surface,

(7) adding to the process gas a precursor additive gas of one of;

(a) an absorption-enhancing species, (b) a transparency-enhancing species;

(8) implanting in the deposited carbon layer one of;

(a) an absorption-enhancing species, (b) a transparency-enhancing species.

6. The method of claim 5 wherein the absorption-enhancing species is one of boron, nitrogen, sulfur.

7. The method of claim 5 wherein the transparency-enhancing species is fluorine.

8. The method of claim 1 further comprising enhancing the adhesion of the deposited carbon layer to the underlying workpiece by setting the bias power or bias voltage to a sufficiently high level.

9. The method of claim 1 further comprising enhancing adhesion o the deposited carbon layer to the underlying workpiece by increasing the level of the bias power.

10. The method of claim 1 further comprising setting stress within the deposited carbon layer to one of compressive stress and tensile stress by adjusting the bias power or bias voltage.

11. The method of claim 1 further comprising increasing compressive stress in the deposited carbon layer by increasing said bias power or bias voltage.

12. The method of claim 1 further comprising controlling the conformality of the deposited carbon layer by setting the level of said RF plasma source power.

13. The method of claim 1 further comprising enhancing optical absorption of the deposited carbon layer by heating the carbon layer following completion of its deposition.

14. The method of claim 13 wherein the carbon layer is heated to about 400 degrees C.

15. The method of claim 1 wherein said process gas is a fluorocarbon gas.

16. The method of claim 4 wherein:

the step of adjusting the energy of ions incident on the workpiece comprises at least one of;

adjusting the bias power or bias voltage,

adjusting the pressure inside the chamber;

the step of adjusting the flux of ions incident on the wafer comprises at least one of;

adjusting the source power;

adjusting the pressure inside the chamber,

adjusting the dilution gas flow rate.

17. The method of claim 5 wherein:

the step of adjusting the energy of ions incident on the workpiece comprises at least one of;

adjusting the bias power or bias voltage,

adjusting the pressure inside the chamber;

the step of adjusting the flux of ions incident on the wafer comprises at least one of;

adjusting the source power;

adjusting the pressure inside the chamber,

adjusting the dilution gas flow rate.

18. The method of claim 1 further comprising including a layer-enhancing additive gas that enhances thermal properties of the deposited carbon layer.

19. The method of claim 18 wherein said layer-enhancing additive gas comprises a combination of a boron-containing gas and a nitrogen-containing gas.

20. The method of claim 19 wherein said process gas comprises a hydrocarbon gas, said boron-containing gas comprises B2H6 and said nitrogen-containing gas comprises N2.