Feature fill with nucleation inhibition

Patent metadata

Field	Value
Publication number	US-11901227-B2
Application number	US-202117497702-A
Country	US
Kind code	B2
Filing date	Oct 8, 2021
Priority date	Sep 30, 2014
Publication date	Feb 13, 2024
Grant date	Feb 13, 2024

Abstract

Described herein are methods of filling features with tungsten, and related systems and apparatus, involving inhibition of tungsten nucleation. In some embodiments, the methods involve selective inhibition along a feature profile. Methods of selectively inhibiting tungsten nucleation can include exposing the feature to a direct or remote plasma. Pre-inhibition and post-inhibition treatments are used to modulate the inhibition effect, facilitating feature fill using inhibition across a wide process window. The methods described herein can be used to fill vertical features, such as in tungsten vias, and horizontal features, such as vertical NAND (VNAND) wordlines. The methods may be used for both conformal fill and bottom-up/inside-out fill. Examples of applications include logic and memory contact fill, DRAM buried wordline fill, vertically integrated memory gate and wordline fill, and 3-D integration using through-silicon vias.

First claim

The invention claimed is:

1. A method comprising:
providing a 3-D structure of a partially manufactured semiconductor substrate, the 3-D structure comprising sidewalls, a plurality of openings in the sidewalls leading to a plurality of features having a plurality of interior regions fluidically accessible through the openings, the plurality of interior regions comprising a tungsten layer deposited on a tungsten nucleation layer;
exposing the tungsten layer of the 3-D structure to diborane; and
after exposing the 3-D structure to diborane, exposing the 3-D structure to an inhibition chemistry to inhibit metal deposition on the tungsten layer.

2. The method of claim 1 , wherein the inhibition chemistry comprises a nitrogen-containing inhibition chemistry.

3. The method of claim 2 , wherein exposing the 3-D structure to an inhibition chemistry comprises exposing the 3-D structure to nitrogen trifluoride (NF 3 ).

4. The method of claim 3 , wherein exposing the 3-D structure to an inhibition chemistry comprises exposing the 3-D structure to a plasma generated from a nitrogen-containing gas.

5. The method of claim 3 , further comprising depositing tungsten in the plurality of features.

6. The method of claim 5 , wherein tungsten is preferentially deposited further in the features than at the feature openings.

7. The method of claim 5 , further comprising, after depositing tungsten in the plurality of features, exposing the 3-D structure to the inhibition chemistry.

8. The method of claim 7 , further comprising, after depositing tungsten in the plurality of features and prior to exposing the 3-D structure to the inhibition chemistry, exposing the 3-D structure to diborane.

9. A method comprising:
providing a feature to be filled with tungsten;
exposing a tungsten layer deposited on a nucleation layer of the feature to diborane; and
after exposing the tungsten layer of the feature to diborane and prior to depositing additional tungsten in the feature, inhibiting tungsten nucleation in the feature.

10. The method of claim 9 , further comprising, depositing additional tungsten in the feature.

11. The method of claim 9 , wherein inhibiting tungsten nucleation in the feature comprising exposing the feature to nitrogen trifluoride (NF 3 ).

12. The method of claim 9 , wherein inhibiting tungsten nucleation in the feature comprises exposing the feature to a plasma.

13. The method of claim 9 , the plasma is generated from a nitrogen-containing gas.

14. The method of claim 13 , wherein the nitrogen-containing gas comprises N 2 .

15. The method of claim 9 , wherein inhibiting tungsten nucleation in the feature is a non-plasma process.

16. The method of claim 9 , wherein the feature is a wordline feature of a 3D NAND structure.

17. The method of claim 16 , wherein wordline feature comprises a constriction formed by pillars of the 3D NAND structure and wherein inhibiting tungsten nucleation in the feature comprises preferentially inhibiting tungsten nucleation at the constriction than at a feature opening.

18. A method comprising:
providing a 3-D structure of a partially manufactured semiconductor substrate, the 3-D structure comprising sidewalls, a plurality of openings in the sidewalls leading to a plurality of features having a plurality of interior regions fluidically accessible through the openings, wherein the plurality of features each comprise a constriction formed by a pillar of the 3-D structure, the plurality of interior regions comprising a tungsten layer deposited on a nucleation layer;
exposing the tungsten layer of the 3-D structure to diborane;
after exposing the tungsten layer of the 3-D structure to diborane, exposing the 3-D structure to nitrogen trifluoride (NF 3 ) to preferentially inhibit tungsten nucleation at the constrictions; and
after exposing the 3-D structure to NF 3 , depositing tungsten in the plurality of features, wherein tungsten is preferentially depositing further within the plurality of features than at the constrictions.

Assignees

• Lam Res Corp

Inventors

• Chandrashekar Anand
• Jeng Esther
• Humayun Raashina
• Danek Michal
• Gao Juwen
• Wang Deqi

Classifications

• H10W20/0245

  comprising use of blind vias during the manufacture · CPC title

• H10W20/0261

  characterised by the filling method or the material of the conductive fill · CPC title

• H10P95/90

  Thermal treatments, e.g. annealing or sintering · CPC title

• H10P95/00

  Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass · CPC title

• H10P14/43

  Chemical deposition, e.g. chemical vapour deposition [CVD] · CPC title