Plasma etching method
A plasma etching method includes a first process of generating a first plasma from a first processing gas that contains fluorine-containing gas and hydrogen-containing gas, by using a first radio frequency power, to etch a laminated film including a first silicon-containing film layer and a second silicon-containing film layer that is different from the first silicon-containing film layer, with the generated first plasma; and a second process that is performed after the first process and includes generating a second plasma from a second processing gas that contains bromine-containing gas, by using a second radio frequency power, to etch the laminated film with the generated second plasma. Unevenness is formed at an interface between the first silicon-containing film layer and the second silicon-containing film layer in the first process, and the unevenness is removed in the second process.
1. A plasma etching method comprising:
generating a first plasma from a first processing gas using a first radio frequency power, the first processing gas containing a fluorine-containing gas and a hydrogen-containing gas, and excluding bromine-containing gas;
etching a laminated film with the first plasma so as to form an etching opening in the laminated film, the laminated film including a first silicon-containing film layer and a second silicon-containing film layer that is different from the first silicon-containing film layer;
generating a second plasma from a second processing gas using a second radio frequency power after etching the laminated film with the first plasma, the second processing gas containing a bromine-containing gas; and
etching the laminated film with the second plasma, wherein
the etching with the first plasma and the etching with the second plasma are performed via a mask on the laminated film,
unevenness is formed on a side wall of the etching opening at an interface of the first silicon-containing film layer and the second silicon-containing film layer during the etching with the first plasma, and
the unevenness is removed during the etching with the second plasma.
2. The plasma etching method according to claim 1 , wherein the etching with the first plasma and the etching with the second plasma are performed under a temperature less than or equal to −30° C.
3. The plasma etching method according to claim 1 , wherein the second processing gas includes the first processing gas.
4. The plasma etching method according to claim 1 , wherein the second processing gas includes a processing gas that is different from the first processing gas.
5. The plasma etching method according to claim 1 , wherein a radio frequency power that is greater than the first radio frequency power or the second radio frequency power is further applied in at least one of the etching with the first plasma or the etching with the second plasma.
6. The plasma etching method according to claim 1 , wherein the fluorine-containing gas is CF 4 and the hydrogen-containing gas is H 2 .
7. The plasma etching method according to claim 1 , wherein the bromine-containing gas is HBr.
8. The plasma etching method according to claim 1 , wherein the first silicon-containing film layer is a silicon oxide layer, and the second silicon-containing film layer is a silicon nitride film layer.
9. The plasma etching method according to claim 1 , wherein a capacitively coupled plasma processing apparatus is used to perform the plasma etching method.
10. The plasma etching method according to claim 1 , wherein an inductively couple plasma processing apparatus is used to perform the plasma etching method.
11. The plasma etching method according to claim 1 , wherein a mask film having an opening is formed on the laminated film.
12. The plasma etching method according to claim 1 , wherein the laminated film consists of alternating layers of the first silicon-containing film layer and the second silicon-containing film layer.
13. The plasma etching method according to claim 1 , wherein at least one of the first radio frequency power and the second radio frequency power is a continuous wave.
14. The plasma etching method according to claim 1 , wherein at least one of the first radio frequency power and the second radio frequency power is a pulse wave.
15. The plasma etching method according to claim 1 , wherein the etching with the first plasma and the etching with the second plasma, which is performed after the etching with the first plasma, are each performed once.
16. The plasma etching method according to claim 1 , wherein after the etching with the first plasma is performed, the first radio frequency power is not turned off and continues to be applied during the etching with the second plasma.
17. The plasma etching method according to claim 5 , wherein the radio frequency power is a continuous wave.
18. The plasma etching method according to claim 5 , wherein the radio frequency power is a pulse wave.
19. A plasma etching method comprising:
preparing a laminated film including a first silicon-containing film layer and a second silicon-containing film layer that is different from the first silicon-containing film layer;
etching the laminated film with a first plasma containing fluorine and hydrogen so as to form an opening in the laminated film, and excluding bromine; and
etching the laminated film with a second plasma containing bromine after etching the laminated film with the first plasma;
wherein
the etching with the first plasma and the etching with the second plasma are performed via a mask on the laminated film,
unevenness is formed on a side wall of the etching opening at an interface of the first silicon-containing film layer and the second silicon-containing film layer during the etching with the first plasma, and
the unevenness is removed during the etching with the second plasma.
20. A plasma etching method comprising:
preparing a laminated film including a first silicon-containing film layer and a second silicon-containing film layer that is different from the first silicon-containing film layer in a chamber;
supplying a first gas that contains fluorine-containing gas and hydrogen-containing gas, and excluding bromine-containing gas, into the chamber; and
applying a first radio frequency power in the chamber so as to form an etching opening in the laminated film;
supplying a second gas that contains a bromine-containing gas into the chamber; and
applying a second radio frequency power in the chamber;
wherein
etching of the laminated film is performed via a mask on the laminated film,
unevenness is formed on a side wall of the etching opening at an interface of the first silicon-containing film layer and the second silicon-containing film layer during the application of the first radio frequency in the chamber, and
the unevenness is removed during the application of the second radio frequency in the chamber.