Pulsed plasma deposition etch step coverage improvement

Patent metadata

Field	Value
Publication number	US-10950430-B2
Application number	US-201916444865-A
Country	US
Kind code	B2
Filing date	Jun 18, 2019
Priority date	Jun 19, 2018
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

Embodiments of the present disclosure relate to methods for in-situ deposition and treatment of a thin film for improved step coverage. In one embodiment, the method for processing a substrate is provided. The method includes forming a dielectric layer on patterned features of the substrate by exposing the substrate to a gas mixture of a first precursor and a second precursor simultaneously with plasma present in a process chamber, wherein the plasma is formed by a first pulsed RF power, exposing the dielectric layer to a first plasma treatment using a gas mixture of nitrogen and helium in the process chamber, and performing a plasma etch process by exposing the dielectric layer to a plasma formed from a gas mixture of a fluorine-containing precursor and a carrier gas, wherein the plasma is formed in the process chamber by a second pulsed RF power.

First claim

The invention claimed is:

1. A method for processing a substrate, comprising:
forming a dielectric layer on exposed surfaces of one or more trenches in the substrate by exposing the substrate to a gas mixture of a first precursor and a second precursor simultaneously with plasma present in a process chamber, wherein the plasma is formed by a first pulsed RF power;
exposing the dielectric layer to a plasma densification treatment using a gas mixture of nitrogen and helium in the process chamber to form a treated dielectric layer;
forming a passivation layer on the treated dielectric layer in the process chamber; and
performing a plasma etch process by exposing the treated dielectric layer and the passivation layer to a plasma formed from a gas mixture of a fluorine-containing precursor and a carrier gas, wherein the plasma is formed in the process chamber by a second pulsed RF power with a frequency of about 5 kHz to about 30 kHz, the plasma etch process etching a top portion of the one or more trenches at a faster rate than at a bottom surface of the one or more trenches.

2. The method of claim 1 , wherein the forming the passivation layer further comprises exposing the treated dielectric layer to a silicon-containing precursor.

3. The method of claim 2 , wherein the silicon-containing precursor comprises silane.

4. The method of claim 2 , wherein the treated dielectric layer is exposed to a nitrogen-containing gas while exposing to the silicon-containing precursor.

5. The method of claim 1 , further comprising:
before and/or after the first plasma densification treatment, purging the process chamber.

6. The method of claim 1 , wherein the trenches have an aspect ratio of about 3:1 to about 10:1.

7. The method of claim 1 , wherein the plasma densification treatment is performed at an RF power of about 300 W to about 1200 W.

8. The method of claim 1 , wherein the plasma etch process prevents a top opening of the one or more trenches from pinching off and a conformal profile of the dielectric layer is obtained.

9. A method for processing a substrate, comprising:
forming a dielectric layer on exposed surfaces of one or more trenches in the substrate by a plasma deposition process, wherein a first plasma is formed by a first pulsed RF power in a process chamber;
densifying the dielectric layer by a plasma treatment to form a treated dielectric layer;
forming a passivation layer on the treated dielectric layer and within the one or more trenches; and
etching a portion of the treated dielectric layer and the passivation layer by a plasma etch process, wherein a second plasma formed from a gas mixture of a fluorine-containing gas and a carrier gas, wherein the second plasma is formed in the process chamber by a second pulsed RF power, a top portion of the one or more trenches etched at a faster rate than at a bottom surface of the one or more trenches.

10. The method of claim 9 , wherein the first and second pulsed RF power has a duty cycle in a range from about 5% to about 30% and a frequency in a range from about 10 kHz to about 20 kHz.

11. The method of claim 9 , wherein the second pulsed RF power has a pulsing width of about 1 μm to about 50 μm.

12. The method of claim 9 , wherein the dielectric layer is silicon nitride.

13. The method of claim 9 , wherein the plasma etch process is performed in a radical-based ambient.

14. The method of claim 9 , wherein the fluorine-containing gas of the plasma etch process comprises NF 3 , F 2 , C 2 F 6 , CF 4 , C 3 F 8 , or SF 6 .

15. The method of claim 14 , wherein the carrier gas of the plasma etch process comprises argon, helium, nitrogen, oxygen, or nitrous oxide.

16. The method of claim 15 , wherein a ratio of the fluorine-containing gas and the carrier gas is in a range of about 1 (fluorine-containing gas):6 (carrier gas) to about 1 (fluorine-containing gas):20 (carrier gas).

17. A method for processing a substrate, comprising:
forming a dielectric layer on patterned features of the substrate by a plasma deposition process, wherein a first plasma is formed by a first pulsed RF power in a process chamber;
densifying the dielectric layer by a plasma treatment using a gas mixture of nitrogen and helium in the process chamber to form a treated dielectric layer;
forming a first passivation layer on the treated dielectric layer;
etching the first passivation layer and a portion of the dielectric layer by a plasma etch process to form an etched dielectric layer, wherein a second plasma is formed in the process chamber by a second pulsed RF power at a frequency of about 5 kHz to about 30 kHz to etch a top surface of the patterned features at a faster etch rate than at a bottom sidewall of the patterned features; and
forming a second passivation layer on the etched dielectric layer.

18. The method of claim 17 , wherein the plasma deposition process comprises flowing a first precursor and a second precursor into the process chamber.

19. The method of claim 18 , wherein the first precursor is a nitrogen-containing precursor comprising ammonia or nitrogen, and the second precursor is a silicon-containing precursor comprising silane or trisilylamine (TSA).

20. The method of claim 17 , wherein the plasma treatment uses a gas mixture of nitrogen and helium in the process chamber.

21. The method of claim 20 , wherein a ratio of the nitrogen and helium in the plasma treatment is in a range of about 1 (nitrogen):3 (helium) to about 1 (nitrogen): 10 (helium).

22. The method of claim 17 , wherein the first and second passivation layers comprise silicon layers.

Assignees

• Applied Materials Inc

Inventors

• Vats Vinayak Veer
• Yu Hang
• Padhi Deenesh
• Li Changling
• Amico Gregory M
• Kamath Sanjay G

Classifications

• H10P50/283 Primary

  by chemical means · CPC title

• H10P50/242

  of Group IV materials · CPC title

• H10P50/28

  of insulating materials · CPC title

• H10P50/00

  Etching of wafers, substrates or parts of devices · CPC title

• H10P14/69433

  the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz · CPC title