Boron doped tungsten carbide for hardmask applications

• US 10,403,502 B2
• Filed: 01/29/2018
• Issued: 09/03/2019
• Est. Priority Date: 02/01/2017
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Venkatasubramanian, Eswaranand, Mallick, Abhijit Basu, Roy, Susmit Singha, Koshizawa, Takehito
• Primary Examiner(s): Nicely, Joseph C.
• Application Number:
  US15/882,204
• Publication Number:
  US 20180218902A1
• Time in Patent Office: 582 Days
• CPC Class Codes: C23C 16/0272 Deposition of sub-layers, e.g. to promote the adhesion of the main coating
• CPC Class Codes: C23C 16/32 Carbides
• CPC Class Codes: C23C 16/342 Boron nitride
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/50 using electric discharges generation and control of plasma in discharge tubes for surface treatment H01J37/32, H01J37/34
• CPC Class Codes: C23C 16/505 using radio frequency discharges
• CPC Class Codes: H01L 21/02175 characterised by the metal H01L21/02197 takes precedence
• CPC Class Codes: H01L 21/02205 the layer being characterised by the precursor material for deposition
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/02304 formation of intermediate layers, e.g. buffer layers, layers to improve adhesion, lattice match or diffusion barriers
• CPC Class Codes: H01L 21/0332 characterised by their composition, e.g. multilayer masks, materials
• CPC Class Codes: H01L 21/31111 by chemical means
• CPC Class Codes: H01L 21/31122 of layers not containing Si, e.g. PZT, Al2O3
• CPC Class Codes: H01L 21/31144 using masks

Abstract

Implementations of the present disclosure generally relate to the fabrication of integrated circuits. More particularly, the implementations described herein provide techniques for deposition of hardmask films on a substrate. In one implementation, a method of forming a hardmask layer on a substrate is provided. The method comprises forming a seed layer on a substrate by supplying a seed layer gas mixture in a processing chamber. The method further includes forming a transition layer comprising tungsten, boron and carbon on the seed layer by supplying a transition layer gas mixture in the processing chamber. The method further includes forming a bulk hardmask layer comprising tungsten, boron and carbon on the transition layer by supplying a main deposition gas mixture in the processing chamber.

Claims

1. A method of forming a hardmask layer on a substrate comprising:

forming a seed layer on a substrate by supplying a seed layer gas mixture in a processing chamber;

forming a transition layer comprising tungsten, boron and carbon on the seed layer by supplying a transition layer gas mixture in the processing chamber; and

forming a bulk hardmask layer comprising tungsten, boron and carbon on the transition layer by supplying a main deposition gas mixture in the processing chamber.

2. The method of claim 1, wherein the transition layer gas mixture comprises at least a boron-based precursor gas, a carbon-based precursor gas and a tungsten-based precursor gas.

3. The method of claim 2, wherein the main deposition gas mixture comprises the boron-based precursor gas, the carbon-based precursor gas and the tungsten-based precursor gas.

4. The method of claim 3, wherein the seed layer gas mixture comprises at least the boron-based precursor gas and the carbon-based precursor gas.

5. The method of claim 3, wherein the boron-based precursor gas is B₂H₆, the carbon-based precursor gas is C₃H₆, and the tungsten-based precursor gas is WF₆.

6. The method of claim 2, wherein the transition layer gas mixture is supplied to the processing chamber by reducing a gas flow rate of the carbon-based precursor gas while maintaining a steady gas flow rate of the boron-based precursor gas.

7. The method of claim 6, wherein the transition layer gas mixture is supplied to the processing chamber by ramping up a gas flow rate of the tungsten-based precursor gas.

8. The method of claim 7, wherein the main deposition gas mixture is supplied to the processing chamber by steadily supplying the boron-based precursor gas, the carbon-based precursor gas, and the tungsten-based precursor gas.

9. The method of claim 8, further comprising supplying a hydrogen-based precursor gas into the processing chamber while forming the seed layer, forming the transition layer, and forming the bulk hardmask layer.

10. The method of claim 9, wherein supplying the hydrogen-based precursor gas into the processing chamber comprises steadily supplying the hydrogen-based precursor gas into the processing chamber.

11. The method of claim 1, further comprising:

ramping a high frequency RF power while forming the seed layer and forming the transition layer; and

steadily supplying the high frequency RF power while forming the bulk hardmask layer.

12. The method of claim 1, further comprising supplying a low frequency RF power while forming the transition layer and forming the bulk hardmask layer.

13. The method of claim 12, further comprising applying a bias to the substrate while supplying the low frequency RF power.

14. The method of claim 1, wherein the seed layer is selected from a boron carbide (BC) seed layer, a boron nitride (BN) seed layer, a boron carbon nitride (BCN) seed layer, a carbon nitride (CN) seed layer, a silicon carbide (SiC) seed layer, a silicon nitride (SiN) seed layer, a boron-based seed layer, a carbon seed layer, a titanium nitride (TiN) seed layer, or a tungsten silicide (WSi) seed layer.

15. A method of forming a hardmask layer comprising:

supplying a gas mixture including at least a boron-based precursor gas and a carbon-based precursor gas onto a surface of a substrate disposed in a processing chamber to form a seed layer on the substrate;

ramping down the carbon-based precursor gas and ramping up a tungsten-based precursor gas supplied in the gas mixture while maintaining a steady flow of the boron-based precursor gas into the processing chamber to form a transition layer on the seed layer; and

continuously supplying the tungsten-based precursor gas in the gas mixture until the tungsten-based precursor gas reaches a predetermined flow rate and maintaining the tungsten-based precursor gas at a steady predetermined flow rate to form a bulk hardmask layer.

16. The method of claim 15, wherein the seed layer is a boron carbide layer, the transition layer is a gradient tungsten boron carbide layer, and the bulk hardmask layer is a tungsten boron carbide layer.

17. The method of claim 15, further comprising:

ramping a high frequency RF power while forming the seed layer and forming the transition layer; and

steadily supplying the high frequency RF power while forming the bulk hardmask layer.

18. A hardmask layer, comprising:

a seed layer, a transition layer and a bulk hardmask layer disposed on the transition layer, wherein the seed layer is a boron carbide layer, the transition layer is a gradient tungsten boron carbide layer and the bulk hardmask layer is a tungsten boron carbide layer.

19. The hardmask layer of claim 18, wherein the hardmask layer comprises from about 50 to about 70 atomic percentage of tungsten, from about 10 to about 30 atomic percentage of carbon, and from about 10 to about 20 atomic percentage of boron.

20. The hardmask layer of claim 18, wherein the hardmask layer has a gradient film structure.