Etching method and etching apparatus

Abstract

We provide technology to improve the etching shape. [Solution] The disclosed etching method includes (a) providing a substrate having a base film, a silicon-containing film on the base film, and a mask on the silicon-containing film into a chamber; (b) etching the silicon-containing film to form recesses using a first plasma generated from a first processing gas containing hydrogen fluoride gas and tungsten-containing gas; and (c) after step (b), further etching the silicon-containing film using a second plasma generated from a second processing gas containing hydrogen fluoride gas, wherein the second processing gas does not contain tungsten-containing gas, or contains tungsten-containing gas at a flow rate less than that of the tungsten-containing gas in the first processing gas.

Claims

1. (a) A step of providing a substrate having a base film, a silicon-containing film on the base film, and a mask on the silicon-containing film into a chamber, (b) A step of etching the silicon-containing film to form recesses using a first plasma generated from a first processing gas containing hydrogen fluoride gas and tungsten-containing gas, (c) After (b) above, a step of further etching the silicon-containing film using a second plasma generated from a second processing gas containing hydrogen fluoride gas, Includes, The second processing gas either does not contain tungsten-containing gas, or contains tungsten-containing gas at a flow rate lower than that of the tungsten-containing gas in the first processing gas. Etching method.

2. The tungsten-containing gas is WF ６ The etching method according to claim 1, including the following:

3. The etching method according to claim 1 or 2, wherein the first processing gas further comprises a phosphorus-containing gas.

4. The etching method according to claim 3, wherein the second processing gas does not contain phosphorus-containing gas, or contains phosphorus-containing gas at a flow rate less than that of the phosphorus-containing gas in the first processing gas.

5. The etching of the silicon-containing film in (b) above is stopped while the silicon-containing film remains between the underlayer film and the bottom of the recess. The etching of the silicon-containing film in (c) above is initiated in the state described above and carried out over a period including the time when the underlying film is exposed. The etching method according to claim 4.

6. The etching method according to claim 1 or 2, wherein the second processing gas further comprises xenon gas.

7. The etching method according to claim 6, wherein the first processing gas does not contain xenon gas, or contains xenon gas at a flow rate less than the flow rate of the xenon gas in the second processing gas.

8. The etching method according to claim 7, wherein each of the first processing gas and the second processing gas contains nitrogen trifluoride gas.

9. The first processing gas includes nitrogen trifluoride gas. The second processing gas either does not contain nitrogen trifluoride gas, or contains nitrogen trifluoride gas at a flow rate lower than that of the nitrogen trifluoride gas in the first processing gas. The second processing gas further contains an oxygen-containing gas and a noble gas. The first processing gas does not contain noble gas, or contains noble gas at a flow rate less than that of the noble gas in the second processing gas. The etching method according to claim 4.

10. The etching method according to claim 1, wherein (b) is performed until the underlying film is exposed in the recess or until at least a portion of the underlying film is exposed in the recess.

11. The etching method according to claim 1, wherein (b) is carried out until a portion of the undercoat is etched.

12. The etching method according to claim 1, comprising performing a cycle including (b) and (c) multiple times.

13. The etching method according to claim 1, wherein (b) is an etching method according to claim 1, wherein the silicon-containing film is etched while forming a first protrusion at a first position of the mask that reduces the width of the opening of the mask, and forming a second protrusion at a second position of the mask below the first position that reduces the width of the opening of the mask.

14. The first processing gas further contains a carbon-containing gas which is the source of the first protrusion. The tungsten-containing gas in the first processing gas is the source of the second protrusion. In (b) above, the amounts of hydrogen species and fluorine species in the first plasma are adjusted so that the second protrusion is formed below the first protrusion. The etching method according to claim 13.

15. In (b) above, a reverse tapered recess is formed in the silicon-containing film, In (c) above, the shape of the recess is made rectangular. The etching method according to claim 1.

16. (a) A step of providing a substrate having a base film, a silicon-containing film on the base film, and a mask on the silicon-containing film into a chamber, (b) A step of etching the silicon-containing film using a first plasma generated from a first processing gas to form a recess, (c) After (b) above, a step of further etching the silicon-containing film using a second plasma generated from a second processing gas, Includes, The first processing gas comprises a single gas or mixed gas containing fluorine and hydrogen, and a metal-containing gas. The second processing gas includes a single gas or mixed gas containing fluorine and hydrogen, The second processing gas either does not contain the metal-containing gas, or contains the metal-containing gas at a flow rate lower than that of the metal-containing gas in the first processing gas. Etching method.

17. The etching method according to claim 16, wherein the metal-containing gas comprises at least one metal selected from the group consisting of tungsten, molybdenum, titanium, and ruthenium.

18. The etching method according to claim 16 or 17, wherein the first processing gas further comprises a phosphorus-containing gas.

19. The etching method according to claim 18, wherein the second processing gas does not contain phosphorus-containing gas, or contains phosphorus-containing gas at a flow rate less than that of the phosphorus-containing gas in the first processing gas.

20. The etching of the silicon-containing film in (b) above is stopped while the silicon-containing film remains between the underlayer film and the bottom of the recess. The etching of the silicon-containing film in (c) above is initiated in the state described above and carried out over a period including the time when the underlying film is exposed. The etching method according to claim 19.

21. The etching method according to claim 16, wherein the second processing gas further comprises a noble gas.

22. The etching method according to claim 21, wherein the first processing gas does not contain the noble gas, or contains the noble gas at a flow rate less than the flow rate of the noble gas in the second processing gas.

23. The etching method according to claim 21 or 22, wherein the noble gas includes at least one selected from the group consisting of argon gas, krypton gas, xenon gas, and radon gas.

24. The etching method according to claim 22, wherein each of the first processing gas and the second processing gas contains nitrogen trifluoride gas.

25. The first processing gas includes nitrogen trifluoride gas. The second processing gas either does not contain nitrogen trifluoride gas, or contains nitrogen trifluoride gas at a flow rate lower than that of the nitrogen trifluoride gas in the first processing gas. The second processing gas further contains an oxygen-containing gas and a noble gas. The first processing gas does not contain noble gas, or contains noble gas at a flow rate less than that of the noble gas in the second processing gas. The etching method according to claim 19.

26. The etching method according to claim 16, wherein (b) is an etching method in which the silicon-containing film is etched while forming a first protrusion at a first position of the mask that reduces the width of the opening of the mask, and forming a second protrusion at a second position of the mask below the first position that reduces the width of the opening of the mask.

27. The first processing gas further contains a carbon-containing gas which is the source of the first protrusion. The metal-containing gas in the first processing gas is the source of the second protrusion. In (b) above, the amounts of hydrogen species and fluorine species in the first plasma are adjusted so that the second protrusion is formed below the first protrusion. The etching method according to claim 26.

28. Chamber and, The substrate support portion in the chamber, Plasma generation section, A control unit configured to control the plasma generation unit, Includes, The control unit, (a) A step of providing a substrate having a base film, a silicon-containing film on the base film, and a mask on the silicon-containing film into the chamber, (b) A step of etching the silicon-containing film to form recesses using a first plasma generated from a first processing gas containing hydrogen fluoride gas and tungsten-containing gas, (c) A step after (b) above, further etching the silicon-containing film using a second plasma generated from a second processing gas containing hydrogen fluoride gas, wherein the second processing gas does not contain the tungsten-containing gas, or contains the tungsten-containing gas at a flow rate lower than that of the tungsten-containing gas in the first processing gas, An etching apparatus configured to perform a process that includes the following.

29. The tungsten-containing gas is WF ６ The etching apparatus according to claim 28, including the following:

30. The etching apparatus according to claim 28 or 29, wherein the first processing gas further comprises a phosphorus-containing gas.

31. The etching apparatus according to claim 30, wherein the second processing gas does not contain phosphorus-containing gas, or contains phosphorus-containing gas at a flow rate less than that of the phosphorus-containing gas in the first processing gas.

32. The control unit, The etching of the silicon-containing film in (b) above is stopped while the silicon-containing film remains between the base film and the bottom of the recess. The etching of the silicon-containing film in (c) above is performed starting in the above state and during a period including when the underlying film is exposed. The etching apparatus according to claim 31, configured as described above.

33. The etching apparatus according to claim 28 or 29, wherein the second processing gas further comprises xenon gas.

34. The etching apparatus according to claim 33, wherein the first processing gas does not contain xenon gas, or contains xenon gas at a flow rate less than the flow rate of the xenon gas in the second processing gas.

35. The etching apparatus according to claim 34, wherein each of the first processing gas and the second processing gas contains nitrogen trifluoride gas.

36. The first processing gas includes nitrogen trifluoride gas. The second processing gas either does not contain nitrogen trifluoride gas, or contains nitrogen trifluoride gas at a flow rate lower than that of the nitrogen trifluoride gas in the first processing gas. The second processing gas further contains an oxygen-containing gas and a noble gas. The first processing gas does not contain noble gas, or contains noble gas at a flow rate less than that of the noble gas in the second processing gas. The etching apparatus according to claim 31.

37. The first processing gas further comprises a carbon-containing gas which is a source for forming a first protrusion at a first position of the mask that reduces the width of the opening of the mask, The tungsten-containing gas in the first processing gas is a source for forming a second protrusion at a second position of the mask below the first position, which reduces the width of the opening of the mask. The control unit is configured to adjust the amount of hydrogen species and fluorine species in the first plasma in order to form the second protrusion below the first protrusion in (b). The etching apparatus according to claim 28.

38. The system further comprises a gas supply unit configured to supply the first processing gas and the second processing gas into the chamber, The control unit is configured to further control the gas supply unit. The etching apparatus according to claim 28.

39. Chamber and, The substrate support portion in the chamber, Plasma generation section, A control unit configured to control the plasma generation unit, Includes, The control unit, (a) A step of providing a substrate having a film to be etched and a mask on the film to be etched into the chamber, (b) A step of etching the film to be etched using plasma generated from a processing gas containing hydrogen fluoride gas to form recesses, The process including (b) is performed, and (b) is performed in the chamber with a metal supply source present, thereby forming a first protrusion at a first position on the mask that reduces the width of the opening of the mask, and forming a second protrusion at a second position on the mask below the first position that reduces the width of the opening of the mask, while etching the film to be etched. Etching equipment.

40. The aforementioned processing gas further contains a metal-containing gas, The metal supply source is the metal-containing gas. The etching apparatus according to claim 39.

41. The etching apparatus according to claim 39, wherein the metal supply source is formed from a metal-containing material and is an upper electrode positioned above the substrate support so as to face the substrate support and / or an edge ring made of the metal-containing material positioned around the substrate supported by the substrate support.

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