Etching method and etching apparatus

Patent metadata

Field	Value
Publication number	US-12283489-B2
Application number	US-202017756979-A
Country	US
Kind code	B2
Filing date	Oct 28, 2020
Priority date	Dec 9, 2019
Publication date	Apr 22, 2025
Grant date	Apr 22, 2025

Abstract

An etching method includes: providing, within a chamber, a substrate that includes at least a silicon-containing material and a molybdenum film or a tungsten film which is in an exposed state, and selectively etching the molybdenum film or the tungsten film relative to the silicon-containing material by supplying, into the chamber, an oxidation gas and a hexafluoride gas as an etching gas.

First claim

What is claimed is:

1. An etching method comprising:
providing, within a chamber, a substrate that includes at least a silicon-containing material and a molybdenum film or a tungsten film which is in an exposed state; and
selectively etching the molybdenum film or the tungsten film relative to the silicon-containing material by supplying, into the chamber, an oxidation gas and a hexafluoride gas as an etching gas,
wherein, in the selectively etching the molybdenum film or the tungsten film relative to the silicon-containing material, the molybdenum film or the tungsten film is etched under a condition in which oxidation becomes dominant, and expansion of vacancy on an etched surface is suppressed.

2. The etching method of claim 1 , wherein the hexafluoride gas is at least one selected from a MoF 6 gas, a WF 6 gas, and a SF 6 gas.

3. The etching method of claim 1 , wherein the oxidation gas is selected from an O 2 gas, an O 3 gas, a NO gas, and a N 2 O gas.

4. The etching method of claim 1 , wherein an etching selectivity of the molybdenum film or the tungsten film relative to the silicon-containing material is 50 or more.

5. The etching method of claim 4 , wherein the substrate further includes at least one of an Al 2 O 3 film and a TiN film as a barrier film under the molybdenum film or the tungsten film, and an etching selectivity of the molybdenum film or the tungsten film relative to the Al 2 O 3 film and the TiN film is 50 or more.

6. The etching method of claim 1 , wherein an etching selectivity of the molybdenum film or the tungsten film relative to the silicon-containing material is 450 or more.

7. The etching method of claim 1 , wherein the silicon-containing material is at least one of a Si film, a SiO 2 film, and a SiN film.

8. The etching method of claim 1 , wherein an internal pressure of the chamber in the selectively etching the molybdenum film or the tungsten film relative to the silicon-containing material ranges from 133.3 to 93,326 Pa.

9. The etching method of claim 1 , wherein a temperature of the substrate in the selectively etching the molybdenum film or the tungsten film relative to the silicon-containing material ranges from 50 to 500 degrees C.

10. The etching method of claim 9 , wherein, when the hexafluoride gas is a MoF 6 gas, the temperature of the substrate in the selectively etching the molybdenum film or the tungsten film relative to the silicon-containing material is 50 to 300 degrees C.

11. The etching method of claim 9 , wherein, when the hexafluoride gas is a WF 6 gas, the temperature of the substrate in the selectively etching the molybdenum film or the tungsten film relative to the silicon-containing material is 200 to 500 degrees C.

12. The etching method of claim 1 , wherein, in the selectively etching the molybdenum film or the tungsten film relative to the silicon-containing material, the oxidation gas and the hexafluoride gas are supplied simultaneously, and a flow rate ratio of the oxidation gas to the hexafluoride gas is adjusted to make the oxidation dominant.

13. The etching method of claim 1 , wherein, in the selectively etching the molybdenum film or the tungsten film relative to the silicon-containing material, the oxidation gas and the hexafluoride gas are sequentially supplied, and a ratio of a time for supplying the oxidation gas to a time for supplying the hexafluoride gas is adjusted to make the oxidation dominant.

14. The etching method of claim 1 , wherein the selectively etching the molybdenum film or the tungsten film relative to the silicon-containing material includes simultaneously supplying the oxidation gas and the hexafluoride gas.

15. The etching method of claim 14 , wherein, in the selectively etching the molybdenum film or the tungsten film relative to the silicon-containing material, a ratio of the hexafluoride gas to the oxidation gas when the oxidation gas and the hexafluoride gas are simultaneously supplied ranges from 10:90 to 99.9:0.1.

16. The etching method of claim 1 , wherein the selectively etching the molybdenum film or the tungsten film relative to the silicon-containing material further includes supplying the oxidation gas prior to the simultaneously supplying the oxidation gas and the hexafluoride gas.

17. The etching method of claim 1 , wherein the selectively etching the molybdenum film or the tungsten film relative to the silicon-containing material includes supplying the oxidation gas first, and subsequently stopping the supplying the oxidation gas and supplying the hexafluoride gas.

18. The etching method of claim 17 , wherein, in the selectively etching the molybdenum film or the tungsten film relative to the silicon-containing material, the supplying the oxidation gas and the supplying the hexafluoride gas are alternately repeated multiple times.

19. The etching method of claim 17 , further comprising:
evacuating an interior of the chamber after the supplying the hexafluoride gas.

20. The etching method of claim 17 , further comprising:
evacuating an interior of the chamber between the supplying the oxidation gas and the supplying the hexafluoride gas.

21. An etching method comprising:
providing, within a chamber, a substrate that includes at least a silicon-containing material and a molybdenum film or a tungsten film which is in an exposed state; and
selectively etching the molybdenum film or the tungsten film relative to the silicon-containing material by supplying, into the chamber, an oxidation gas and a hexafluoride gas as an etching gas,
wherein the selectively etching the molybdenum film or the tungsten film relative to the silicon-containing material includes: a first stage of supplying, into the chamber, the oxidation gas and the hexafluoride gas as the etching gas to etch the molybdenum film or the tungsten film, and a second stage of supplying the hexafluoride gas as the etching gas and switching to a condition in which oxidation becomes dominant to etch the molybdenum film or the tungsten film.

22. The etching method of claim 21 , wherein, in the second stage, the oxidation gas and the hexafluoride gas are supplied simultaneously, and a flow rate ratio of the oxidation gas to the hexafluoride gas is adjusted to make the oxidation dominant.

23. The etching method of claim 21 , wherein, in the second stage, the oxidation gas and the hexafluoride gas are sequentially supplied, and a ratio of a time for supplying the oxidation gas to a time for supplying the hexafluoride gas is adjusted to make the oxidation dominant.

Assignees

• Tokyo Electron Ltd

Inventors

• Toda Satoshi
• Shindo Naoki
• Tachibana Mitsuhiro
• Suzuki Haruna
• You Gen

Classifications

• H10P72/0421

  for drying etching · CPC title

• H10P50/642

  Chemical etching · CPC title

• H10P50/266 Primary

  by vapour etching only · CPC title

• H10P72/7604

  the wafers being placed on a susceptor, stage or support · CPC title

• H10P72/0432

  mainly by conduction · CPC title