Pulsing RF power in etch process to enhance tungsten gapfill performance

Patent metadata

Field	Value
Publication number	US-9978610-B2
Application number	US-201615240807-A
Country	US
Kind code	B2
Filing date	Aug 18, 2016
Priority date	Aug 21, 2015
Publication date	May 22, 2018
Grant date	May 22, 2018

Abstract

Methods and apparatuses for filling features with metal materials such as tungsten-containing materials in a substantially void-free manner are provided. In certain embodiments, the method involves depositing an initial layer of a metal such as a tungsten-containing material followed by removing a portion of the initial layer to form a remaining layer, which is differentially passivated along the depth of the high-aspect ratio feature. The portion may be removed by exposing the tungsten-containing material to a plasma generated from a fluorine-containing nitrogen-containing gas and pulsing and/or ramping the plasma during the exposure.

First claim

What is claimed is:

1. A method comprising:
providing a substrate having a feature partially filled with a metal to a process chamber having a radio frequency plasma source for generating a capacitively coupled or inductively coupled plasma;
exposing the partially filled feature to a fluorine- and nitrogen-based plasma generated by the radio frequency plasma source to remove a portion of the metal; and
pulsing the radio frequency plasma source for generating the capacitively coupled or inductively coupled plasma during the exposure.

2. The method of claim 1 , wherein the metal is tungsten.

3. The method of claim 1 , wherein the radio frequency plasma source is pulsed between an ON state and an OFF state, wherein plasma power during the OFF state is 0 W and the plasma power during the ON state is between about 50 W and about 3000 W.

4. The method of claim 1 , wherein the radio frequency plasma source is pulsed at a frequency between about 1 Hz and about 400 kHz.

5. The method of claim 1 , wherein the radio frequency plasma source is pulsed using a duty cycle between about 10% and about 90%.

6. The method of claim 1 , wherein the radio frequency plasma source is pulsed between an ON state and an OFF state, and wherein the plasma is in the ON state for a duration between about 100 milliseconds and about 10 seconds in each pulse.

7. The method of claim 1 , wherein exposing the partially filled feature to the fluorine- and nitrogen-based plasma comprises flowing a fluorine- and nitrogen-containing gas and igniting the fluorine- and nitrogen-based plasma using the radio frequency plasma source.

8. The method of claim 7 , wherein fluorine- and nitrogen-containing gas flow is pulsed.

9. The method of claim 8 , wherein the fluorine- and nitrogen-containing gas flow is pulsed using a duty cycle between about 30% and about 70%.

10. The method of claim 8 , wherein the fluorine- and nitrogen-containing gas flow is pulsed for a pulse duration between about 0.5 seconds and about 3 seconds.

11. The method of claim 8 , wherein the fluorine- and nitrogen-containing gas is nitrogen trifluoride.

12. The method of claim 1 , further comprising, after removing the portion of the metal, exposing the substrate to a metal-containing precursor to deposit additional metal in the feature.

13. A method comprising:
providing a substrate having a feature partially filled with tungsten to a process chamber having a radio frequency plasma source for generating a capacitively coupled or inductively coupled plasma;
introducing a fluorine- and nitrogen-containing gas to the process chamber;
pulsing flow of the fluorine- and nitrogen-containing gas; and
igniting an inductively coupled or capacitively coupled plasma in the process chamber to generate a fluorine- and nitrogen-based plasma to etch a portion of the tungsten; and
pulsing the radio frequency plasma source for generating the capacitively coupled or inductively coupled plasma during the igniting of the plasma.

14. The method of claim 13 , wherein fluorine- and nitrogen-containing gas flow is pulsed using a duty cycle between about 30% and about 70%.

15. The method of claim 13 , wherein fluorine- and nitrogen-containing gas flow is pulsed for a duration between about 0.5 seconds and about 3 seconds.

16. The method of claim 13 , wherein the fluorine- and nitrogen-containing gas is nitrogen trifluoride.

17. The method of claim 13 , wherein the plasma is pulsed between an ON state and an OFF state, wherein plasma power during the OFF state is 0 W and the plasma power during the ON state is between about 50 W and about 3000 W.

18. The method of claim 13 , wherein the plasma is pulsed at a frequency between about 1 Hz and about 400 kHz.

Assignees

• Lam Res Corp

Inventors

• Fung Waikit
• Meng Liang
• Chandrashekar Anand

Classifications

• H10P72/0421

  for drying etching · CPC title

• H10P14/418

  the conductive layers comprising transition metals · CPC title

• H10P14/43

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

• H10W20/056

  by filling conductive material into holes, grooves or trenches · CPC title

• H10P50/267 Primary

  using plasmas · CPC title