Plasma processing method
View Patent ↗According to one embodiment of the present invention, there is provided a plasma processing method for forming a pattern of a mask on a laminated film of a magnetic film and a metal oxide film, and the plasma processing method includes: plasma etching the magnetic film in a chamber; and after the plasma etching, plasma cleaning the chamber, wherein the plasma cleaning performs first plasma cleaning of plasma cleaning using a gas mixture of chlorine element-containing gas and boron trichloride gas, and after the first plasma cleaning, second plasma cleaning of removing boron remaining in the chamber.
1. A plasma processing method for transcribing a pattern of a mask onto a laminated film in which a first magnetic film, a metal oxide film arranged over the first magnetic film, and a second magnetic film arranged over the metal oxide film are deposited, the plasma processing method comprising:
etching to plasma-etch the second magnetic film using the mask in a chamber; and
cleaning to plasma-clean the chamber, in which the second magnetic film is plasma-etched, after the etching,
wherein the cleaning includes:
a first plasma cleaning to plasma-clean using a gas mixture of a chlorine gas and boron trichloride gas, and
after the first plasma-cleaning and before another etching in the chamber, a second plasma-cleaning to plasma-clean using a gas mixture of carbon tetrafluoride gas and oxygen gas.
2. The plasma processing method according to claim 1 ,
wherein the first and second magnetic films contain at least one of iron, cobalt, and nickel elements, respectively.
3. The plasma processing method according to claim 1 ,
wherein the etching reaches the first magnetic film.
4. The plasma processing method according to claim 1 ,
wherein the etching does not reach the first magnetic film.
5. The plasma processing method according to claim 1 ,
wherein the metal oxide film is a magnesium oxide film.
6. The plasma processing method according to claim 1 ,
wherein the mask includes a tantalum film, and
wherein in the etching, the second magnetic film is etched using chlorine gas.
7. The plasma processing method according to claim 6 ,
wherein the laminated film functions as a magnetic tunnel junction (MTJ) device having a structure in which the metal oxide film is interposed between the first and second magnetic films.
8. The plasma processing method according to claim 1 ,
wherein, in the etching, the second magnetic film is etched using an inductively-coupled plasma etching apparatus having a Faraday shield, and
wherein a radio frequency voltage applied to the Faraday shield during the second plasma-cleaning is lower than a radio frequency voltage applied to the Faraday shield during the first plasma-cleaning.
9. A plasma processing method for transcribing a pattern of a mask onto a laminated film in which a first magnetic film, a metal oxide film arranged over the first magnetic film, and a second magnetic film arranged over the metal oxide film are deposited, the plasma processing method comprising:
etching to plasma-etch the second magnetic film using the mask in a chamber, the etching producing deposits containing one or more etched materials in the chamber; and
cleaning to plasma-clean the chamber to remove the deposits, in which the second magnetic film is plasma-etched, after the etching,
wherein the cleaning includes:
first plasma cleaning to plasma-clean the chamber to remove the deposits using a gas mixture of a chlorine element-containing gas and boron trichloride gas, the first plasma cleaning producing residual boron in the chamber from the boron trichloride gas, and
after the first plasma-cleaning and before another etching in the chamber, a second plasma-cleaning to remove the residual boron remaining in the chamber, and
wherein the second plasma cleaning uses a gas mixture of carbon tetrafluoride gas and oxygen element-containing gas.
10. The plasma processing method according to claim 9 ,
wherein the first and second magnetic films each contain at least one of iron, cobalt, or nickel elements.
11. The plasma processing method according to claim 9 ,
wherein the etching reaches the first magnetic film.
12. The plasma processing method according to claim 9 ,
wherein the etching does not reach the first magnetic film.
13. The plasma processing method according to claim 9 ,
wherein the metal oxide film is a magnesium oxide film, and
wherein the oxygen element-containing gas is oxygen gas.
14. The plasma processing method according to claim 13 ,
wherein the chlorine element-containing gas is chlorine gas.
15. The plasma processing method according to claim 14 ,
wherein the mask includes a tantalum film, and
wherein in the etching, the second magnetic film is etched using chlorine gas.
16. The plasma processing method according to claim 15 ,
wherein the laminated film functions as a magnetic tunnel junction (MTJ) device having a structure in which the metal oxide film is interposed between the first and second magnetic films.
17. A plasma processing method for transcribing a pattern of a mask onto a laminated film in which a first magnetic film, a metal oxide film arranged over the first magnetic film, and a second magnetic film arranged over the metal oxide film are deposited, the plasma processing method comprising:
etching to plasma-etch the second magnetic film using the mask in a chamber, the etching producing deposits containing one or more etched materials in the chamber; and
cleaning to plasma-clean the chamber to remove the deposits, in which the second magnetic film is plasma-etched, after the etching,
wherein the cleaning includes:
first plasma cleaning to plasma-clean the chamber to remove the deposits using a gas mixture of a chlorine element-containing gas and boron trichloride gas, the first plasma cleaning producing residual boron in the chamber from the boron trichloride gas, and
after the first plasma-cleaning and before another etching in the chamber, a second plasma-cleaning to remove the residual boron remaining in the chamber,
wherein the second plasma cleaning uses a gas mixture of carbon tetrafluoride gas and oxygen element-containing gas,
wherein, in the etching, the second magnetic film is etched using an inductively-coupled plasma etching apparatus having a Faraday shield, and
wherein a radio frequency voltage applied to the Faraday shield during the second plasma-cleaning using the gas mixture of carbon tetrafluoride gas and oxygen element-containing gas is lower than a radio frequency voltage applied to the Faraday shield during the first plasma-cleaning using the gas mixture of the chlorine element-containing gas and boron trichloride gas.
18. The plasma processing method according to claim 17 ,
wherein the metal oxide film is a magnesium oxide film, and
wherein the oxygen element-containing gas is oxygen gas.
19. The plasma processing method according to claim 18 ,
wherein the chlorine element-containing gas is chlorine gas.