Method for manufacturing semiconductor device

1. A method for manufacturing a semiconductor device, the method comprising:

forming a hole extending in a first direction in a workpiece, the workpiece including a first layer of a first material, a second layer of a second material stacked on the first layer in the first direction, a third layer of the first material stacked on the second layer in the first direction, and a fourth layer of the second material stacked on the third layer in the first direction;

forming a first film on an upper surface of the workpiece and an upper portion of a side wall of the hole;

forming a second film on a surface of the first film;

selectively removing the first film and the second film at the same time from the upper surface of the workpiece using a first etchant so that at least a part of the first film formed on the upper portion and at least a part of the second film formed on the surface of the first film remain; and

removing at least a part of a portion of the workpiece which is exposed through the hole using a second etchant,

wherein an etching rate of the first film by the first etchant is higher than an etching rate of the second film by the first etchant.

2. The method according to claim 1 , wherein the first layer includes a silicon oxide, and the second layer includes a silicon nitride.

3. The method according to claim 1 , wherein the first film is formed using a gas including hydrocarbon.

4. The method according to claim 1 , wherein the first film includes a carbon film, and the second film includes a metal oxide film.

5. The method according to claim 4 , wherein a metallic element included in the metal oxide film includes at least one element selected from the group consisting of tungsten, molybdenum, titanium, aluminum, rhenium, iridium, platinum, and ruthenium.

6. The method according to claim 5 , wherein the forming of the second film is performed in a chamber in which the forming of the first film is performed.

7. The method according to claim 6 , wherein the selectively removing using the first etchant is performed in the chamber.

8. The method according to claim 7 , wherein

in the forming of the first film, a part of the first film is formed on at least part of an inner wall of the chamber, and

in the forming of the second film, a part of the second film is formed on at least part of the first film formed on the inner wall of the chamber.

9. The method according to claim 8 , wherein the removing using the first etchant includes:

removing at least a part of the first film formed on the inner wall of the chamber, and at least a part of the second film formed on the first film on the inner wall of the chamber.

10. The method according to claim 9 , wherein the removing using the second etchant is performed in the chamber.

11. The method according to claim 10 , wherein the forming of the hole is performed in the chamber.

12. The method according to claim 11 , wherein

the forming of the first film includes supplying first power from a first power source to a stage where the workpiece is placed,

the forming of the second film includes supplying third power from the first power source and fourth power from a second power source to the stage, and supplying fifth power from a third power source to an electrode,

the workpiece is placed between the stage and the electrode,

a third frequency of the third power is different from a fourth frequency of the fourth power, and

a fifth frequency of the fifth power is lower than any one of the third frequency and the fourth frequency.

13. The method according to claim 12 , wherein the fifth frequency is the same as any one of the third frequency and the fourth frequency.

14. The method according to claim 13 , wherein the removing using the first etchant includes:

supplying sixth power from the first power source and seventh power from the second power source to the stage, and

supplying eighth power from the third power source to the electrode, wherein

a sixth frequency of the sixth power is different from a seventh frequency of the seventh power, and

an eighth frequency of the eighth power is lower than any one of the sixth frequency and the seventh frequency.

15. The method according to claim 14 , wherein the eighth frequency is the same as any one of the sixth frequency and the seventh frequency.

16. The method according to claim 15 , wherein the eighth frequency is the same as any one of the third frequency and the fourth frequency.

17. The method according to claim 16 , wherein the first etchant includes at least one of an oxygen ion and a hydrogen ion.

18. The method according to claim 17 , wherein the second etchant includes fluorine and carbon.

19. The method according to claim 1 , wherein the selectively removing the first film and the second film at the same time comprises etching the first film with the first etchant and removing the second film by a lift-off effect.

20. A method for manufacturing a semiconductor device, the method comprising:

forming a hole extending in a first direction in a workpiece, the workpiece including a first layer of a first material, a second layer of a second material stacked on the first layer in the first direction, a third layer of the first material stacked on the second layer in the first direction, and a fourth layer of the second material stacked on the third layer in the first direction;

forming a first film on an upper surface of the workpiece and an upper portion of a side wall of the hole, wherein the first film is formed using a gas including methane;

forming a second film on a surface of the first film;

selectively removing the first film and the second film from the upper surface of the workpiece using a first etchant so that at least a part of the first film formed on the upper portion and at least a part of the second film formed on the surface of the first film remain; and

removing at least a part of a portion of the workpiece which is exposed through the hole using a second etchant,

wherein an etching rate of the first film by the first etchant is higher than an etching rate of the second film by the first etchant.

21. A method for manufacturing a semiconductor device, the method comprising:

forming a hole extending in a first direction in a workpiece, the workpiece including a first layer of a first material, a second layer of a second material stacked on the first layer in the first direction, a third layer of the first material stacked on the second layer in the first direction, and a fourth layer of the second material stacked on the third layer in the first direction;

forming a first film on an upper surface of the workpiece and an upper portion of a side wall of the hole;

forming a second film on a surface of the first film, wherein the forming of the second film includes:

forming the second film using a gas including at least one selected from the group consisting of tungsten hexafluoride, molybdenum hexafluoride, rhenium hexafluoride, iridium hexafluoride, platinum hexafluoride, titanium tetrachloride, ruthenium tetroxide, and trimethylaluminum, and an oxygen gas;

selectively removing the first film and the second film from the upper surface of the workpiece using a first etchant so that at least a part of the first film formed on the upper portion and at least a part of the second film formed on the surface of the first film remain; and

removing at least a part of a portion of the workpiece which is exposed through the hole using a second etchant,

wherein an etching rate of the first film by the first etchant is higher than an etching rate of the second film by the first etchant.