Tungsten for wordline applications

• US 9,953,984 B2
• Filed: 02/10/2016
• Issued: 04/24/2018
• Est. Priority Date: 02/11/2015
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Danek, Michal, Bamnolker, Hanna, Humayun, Raashina, Gao, Juwen
• Primary Examiner(s): BOOTH, RICHARD A
• Application Number:
  US15/040,561
• Publication Number:
  US 20160233220A1
• Time in Patent Office: 804 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 16/08 from metal halides
• CPC Class Codes: C23C 16/30 Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
• CPC Class Codes: H01L 21/28088 the final conductor layer next to the insulator being a composite, e.g. TiN
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76876 for deposition from the gas phase, e.g. CVD
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material
• CPC Class Codes: H01L 23/53257 the principal metal being a refractory metal
• CPC Class Codes: H01L 23/53266 Additional layers associated with refractory-metal layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 29/40117 the electrodes comprising a charge-trapping insulator
• CPC Class Codes: H10B 12/34 the transistor being at least partially in a trench in the substrate
• CPC Class Codes: H10B 12/488 Word lines
• CPC Class Codes: H10B 41/27 the channels comprising vertical portions, e.g. U-shaped channels
• CPC Class Codes: H10B 43/27 the channels comprising vertical portions, e.g. U-shaped channels

Abstract

Disclosed herein are methods and related apparatus for formation of tungsten wordlines in memory devices. Also disclosed herein are methods and related apparatus for deposition of fluorine-free tungsten (FFW). According to various embodiments, the methods involve deposition of multi-component tungsten films using tungsten chloride (WCl_x) precursors and boron (B)-containing, silicon (Si)-containing or germanium (Ge)-containing reducing agents.

Claims

1. A method of depositing tungsten on a substrate, the method comprising:

pulsing a reducing agent, wherein the reducing agent is boron (B)-containing, silicon (Si)-containing or germanium (Ge)-containing; and

pulsing a tungsten chloride precursor,

wherein the tungsten chloride precursor is reduced by the reducing agent or a product thereof to form a multi-component tungsten-containing film containing one or more of B, Si, and Ge on the substrate, wherein the multi-component tungsten-containing film contains between 5% and 60% (atomic) B, Si, or Ge, and wherein the between 5% and 60% (atomic) B, Si, or Ge is provided by the reducing agent.

2. The method of claim 1, further comprising pulsing a third reactant to form a ternary tungsten-containing film.

3. The method of claim 1, wherein the multi-component film is a binary film.

4. The method of claim 1, wherein the multi-component tungsten-containing film is a diffusion barrier for a wordline.

5. The method of claim 1, wherein the multi-component tungsten-containing film is a work function layer for a metal gate.

6. The method of claim 1, wherein the substrate temperature during the tungsten chloride pulse is at least 400°

C.

7. The method of claim 1, wherein the temperature during the tungsten chloride pulse is at least 450°

C.

8. The method of claim 1, wherein the temperature during the tungsten chloride pulse is at least 500°

C.

9. The method of claim 1, wherein the substrate temperature during the reducing agent and tungsten chloride pulses is at least 400°

C.

10. The method of claim 1, wherein the substrate temperature during the reducing agent and tungsten chloride pulses is at least 450°

C.

11. The method of claim 1, wherein the substrate temperature during the reducing agent and tungsten chloride pulses is at least 500°

C.

12. The method of claim 1, further comprising depositing a bulk tungsten (W) layer on the multi-component tungsten-containing film.

13. The method of claim 12, wherein the bulk W layer is deposited by a chemical vapor deposition (CVD) reaction between a tungsten chloride precursor and a reducing agent.

14. The method of claim 12, wherein the bulk W layer is deposited directly on the multi-component tungsten-containing film without an intervening layer.

15. The method of claim 1, wherein the multi-component tungsten-containing film is deposited directly on an insulating film.

16. The method of claim 15, wherein the insulating film is an oxide or nitride film.

17. The method of claim 1, wherein the method further comprises decomposition of the reducing agent to form a layer of B, Si, or Ge on the substrate.

18. The method of claim 1, wherein the multi-component tungsten-containing film contains between 15% and 50% (atomic) B, Si, or Ge.

19. The method of claim 1, wherein the multi-component tungsten-containing film is selected from the group consisting of WGe_x, WGe_xN_y, WGe_xC_y, WB_xGe_yN_z, and WGe_xC_yN_z wherein x, y, and z are numbers greater than zero.

20. A method of depositing tungsten on a substrate, the method comprising:

pulsing a (Ge)-containing reducing agent; and

pulsing a tungsten chloride precursor, wherein the tungsten chloride precursor is reduced by the Ge-containing reducing agent or a product thereof to form a multi-component tungsten-containing film containing between 5% and 60% (atomic) Ge, wherein the between 5% and 60% (atomic) Ge is provided by the Ge-containing reducing agent.