Methods of etching films with reduced surface roughness

Patent metadata

Field	Value
Publication number	US-9896770-B2
Application number	US-201615383556-A
Country	US
Kind code	B2
Filing date	Dec 19, 2016
Priority date	Jul 29, 2014
Publication date	Feb 20, 2018
Grant date	Feb 20, 2018

Abstract

Provided are methods for etching films comprising transition metals which help to minimize higher etch rates at the grain boundaries of polycrystalline materials. Certain methods pertain to amorphization of the polycrystalline material, other pertain to plasma treatments, and yet other pertain to the use of small doses of halide transfer agents in the etch process.

First claim

What is claimed is:

1. A method comprising:
providing a polycrystalline film comprising a transition metal;
exposing the polycrystalline film to a plasma to amorphize at least a portion of the polycrystalline film to provide an amorphous region;
activating at least a portion of the polycrystalline film to provide an activated surface; and
etching at least a portion of the activated surface by exposing the activated surface to a reagent comprising a Lewis base or pi acid.

2. The method of claim 1 , wherein etching the activated surface comprises creating a vapor phase coordination complex of the transition metal coordinated to one or more ligands from the reagent.

3. The method of claim 1 , wherein the Lewis base or pi acid comprises a chelating amine represented by the structure:

wherein each R a is independently hydrogen or C1-C4 alkyl group with the proviso that not all of the R a groups are hydrogen.

4. The method of claim 3 , wherein the chelating amine is selected from the group consisting of N,N,N′,N′-tetramethylethylene diamine (TMEDA), ethylene diamine, N,N′-dimethylethylenediamine, 2-(aminomethyl)pyridine, 2-[(alkylamino)methyl]pyridine, and 2-[(dialkylamino)methyl]pyridine, wherein the alkyl group is a C1-C6 alkyl group.

5. The method of claim 1 , wherein the Lewis base or pi acid comprises CO, PR 1 3 , wherein each R 1 is independently a C1-C6 alkyl group, 1,2-bis(difluorophosphino)ethane, N 2 O, NO, NH 3 , NR 2 3 , wherein each R 2 is independently hydrogen C1-C6 branched or unbranched, substituted or unsubstituted, alkyl, allyl or cyclic hydrocarbon or heteroatomic group, or a compound having the structure:

wherein each R b is independently hydrogen, R or C1-C4 alkyl.

6. The method of claim 1 , wherein the pi acid comprises AlHnXmRcp, wherein X is a halogen, the sum of n+m+p is 3, and Rc is C1-C6 alkyl.

7. The method of claim 1 , wherein activating at least a portion of the polycrystalline film comprises exposing the polycrystalline film to a transfer agent selected from the group consisting of Cl 2 , Br 2 and I 2 .

8. The method of claim 1 , wherein the polycrystalline film comprises cobalt.

9. The method of claim 1 , wherein the polycrystalline film comprises a metal selected from the group consisting of Co, Cu, Ru, Ni, Fe, Pt, Mn and Pd.

10. The method of claim 1 , further comprising repeating amorphizing, activating and etching the substrate.

11. A method of etching a substrate, the method comprising:
providing a polycrystalline film comprising cobalt;
amorphizing the polycrystalline film by exposing the polycrystalline film to an inert plasma, reducing gas or reagent vapor;
activating at least a portion of the amorphized polycrystalline film by exposing the amorphized polycrystalline film to a halide transfer agent to provide an activated substrate surface; and
exposing the activated substrate surface to a reagent comprising a Lewis base or pi acid to provide a vapor phase coordination complex comprising one or more cobalt atoms coordinated to one or more ligands from the reagent.

12. The method of claim 11 , wherein the Lewis base or pi acid comprises CO, PR 1 3 , wherein each R 1 is independently a C1-C6 alkyl group, 1,2-bis(difluorophosphino)ethane, N 2 O, NO, NH 3 , NR 2 3 , wherein each R 2 is independently hydrogen C1-C6 branched or unbranched, substituted or unsubstituted, alkyl, allyl or cyclic hydrocarbon or heteroatomic group, or a compound having the structure:

wherein each R b is independently hydrogen, R or C1-C4 alkyl.

13. The method of claim 11 , wherein the pi acid comprises AlH n X m R c p , wherein X is a halogen, the sum of n+m+p is 3, and R c is C1-C6 alkyl.

14. The method of claim 13 , wherein the Lewis base or pi acid comprises a chelating amine selected from the group consisting of N,N,N′,N′-tetramethylethylene diamine, ethylene diamine, N,N′-dimethylethylenediamine, 2-(aminomethyl)pyridine, 2-[(alkylamino)methyl]pyridine, and 2-[(dialkylamino)methyl]pyridine, wherein the alkyl group is C1-C6 alkyl.

15. The method of claim 11 , wherein the halide transfer agent is selected from the group consisting of Cl 2 , Br 2 and I 2 .

16. The method of claim 11 , wherein the polycrystalline film further comprises one or more metal selected from Cu, Ru, Ni, Fe, Pt, Mn or Pd.

Assignees

• Applied Materials Inc

Inventors

• Schmiege Benjamin
• Ingle Nitin K
• Nemani Srinivas D
• Anthis Jeffrey W
• Wang Xikun
• Liu Jie
• Benjaminson David

Classifications

• H01J37/32009

  Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources (plasma generation in general H05H1/24) · CPC title

• C30B33/12

  in gas atmosphere or plasma · CPC title

• C23F1/12 Primary

  Gaseous compositions · CPC title

• C23F4/00

  Processes for removing metallic material from surfaces, not provided for in group C23F1/00 or C23F3/00 · CPC title

• H01J2237/334

  Etching · CPC title