Substrate processing method and substrate processing apparatus

1 . A substrate processing method for a substrate processing apparatus, the method comprising:

(a) supplying a process gas with a specific condition, to a processing container having therein a stage on which a workpiece having an etching target film and a mask on the etching target film is placed;

(b) performing a plasma processing on the workpiece with first plasma generated from the process gas under a first plasma generation condition, and forming a protective film on the workpiece by a reaction product generated by the first plasma;

(c) performing a plasma processing on the workpiece with second plasma generated from the process gas under a second plasma generation condition that is different from the first plasma generation condition in a radio-frequency condition and a processing time, and is same as the first plasma generation condition in other conditions, and etching the etching target film by an etchant generated by the second plasma; and

(d) repeating (b) and (c), wherein

the second plasma is in a state where a dissociation degree of the process gas is higher than that of the first plasma.

2 . The substrate processing method according to claim 1 , wherein the second plasma generation condition is a condition in which a bias potential is generated on the workpiece.

3 . The substrate processing method according to claim 1 , wherein the etching target film is a silicon film,

the mask is a silicon-containing film, and

the process gas includes fluorocarbon gas or hydrofluorocarbon gas.

4 . The substrate processing method according to claim 3 , wherein the process gas further includes a halogen-containing gas.

5 . The substrate processing method according to claim 4 , wherein the halogen-containing gas does not contain carbon.

6 . The substrate processing method according to claim 1 , wherein the process gas includes:

a first gas capable of generating a precursor that forms a deposit on the workpiece by being dissociated by plasma, and

a second gas capable of generating a precursor that etches the etching target film by being dissociated by the plasma.

7 . The substrate processing method according to claim 1 , wherein the first plasma is capacitively coupled plasma, and

the second plasma is inductively coupled plasma.

8 . The substrate processing method according to claim 1 , wherein the first plasma is capacitively coupled plasma, and

the second plasma is microwave plasma.

9 . The substrate processing method according to claim 1 , wherein the first plasma and the second plasma are inductively coupled plasma or capacitively coupled plasma, and

a frequency of the radio-frequency power in the second plasma generation condition is higher than a frequency of the radio-frequency power in the first plasma generation condition.

10 . The substrate processing method according to claim 1 , wherein the first plasma and the second plasma are inductively coupled plasma or capacitively coupled plasma, and

an applied power of a radio-frequency power in the second plasma generation condition is higher than an applied power of the radio-frequency power in the first plasma generation condition.

11 . The substrate processing method according to claim 10 , wherein the first plasma generation condition includes changing the applied power over time as the radio-frequency power condition.

12 . The substrate processing method according to claim 1 , wherein the radio-frequency power condition and the processing time in the first and second plasma generation conditions are adjusted according to a depth of the etching target film that is etched.

13 . A substrate processing method for a substrate processing apparatus, the method comprising:

(a) supplying a process gas with a specific condition, to a processing container having therein a stage on which a workpiece having an etching target film and a mask on the etching target film is placed;

(b) performing a plasma processing on the workpiece with first plasma generated from the process gas under a first plasma generation condition;

(c) performing a plasma processing on the workpiece with second plasma generated from the process gas under a second plasma generation condition that is different from the first plasma generation condition in a radio-frequency condition and a processing time, and is same as the first plasma generation condition in other conditions;

(e) performing a processing in which no plasma is generated; and

(f) repeating (b), (c), and (e) in an order of (b), (c), and (e).

14 . The substrate processing method according to claim 13 , wherein a condition of the process gas introduced in (e) is same as conditions of the process gas introduced in (b) and (c).

15 . A substrate processing method for a substrate processing apparatus, the method comprising:

(a) supplying a process gas with a specific condition, to a processing container having therein a stage on which a workpiece having an etching target film and a mask on the etching target film is placed;

(b) performing a plasma processing on the workpiece with first plasma generated from the process gas under a first plasma generation condition,

(c) performing a plasma processing on the workpiece with second plasma generated from the process gas under a second plasma generation condition that is different from the first plasma generation condition in a radio-frequency condition and a processing time, and is same as the first plasma generation condition in other conditions;

(d) repeating (b) and (c); and

(f) performing a plasma processing on the workpiece with third plasma generated from the process gas under a third plasma generation condition that is different from the first and second plasma generation conditions in the radio-frequency condition and the processing time, and is same as the first and second plasma generation conditions in other conditions,

wherein (f) is performed immediately before and/or immediately after (b).

16 . The substrate processing method according to claim 15 , wherein the third plasma is in a state where a dissociation degree of the process gas is higher than that of the first plasma and lower than that of the second plasma.

17 . The substrate processing method according to claim 16 , wherein the third plasma is inductively coupled plasma or capacitively coupled plasma, and

a frequency of the radio-frequency power in the third plasma generation condition is higher than a frequency of the radio-frequency power in the first plasma generation condition and lower than a frequency of the radio-frequency power in the second plasma generation condition.

18 . The substrate processing method according to claim 16 , wherein the third plasma is inductively coupled plasma or capacitively coupled plasma, and

an applied power of a radio-frequency power in the third plasma generation condition is higher than an applied power of the radio-frequency power in the first plasma generation condition and lower than an applied power of the radio-frequency power in the second plasma generation condition.

19 . The substrate processing method according to claim 18 , wherein the first and third plasma generation conditions include changing the applied power over time as the radio-frequency power condition.

20 . The substrate processing method according to claim 16 , wherein the radio-frequency power condition and the processing time in the first, second, and third plasma generation conditions are adjusted according to a depth of the etching target film that is etched.

21 . The substrate processing method according to claim 15 , wherein, in (f), a protective film is formed on the workpiece by a reaction product generated by the third plasma.

22 . The substrate processing method according to claim 21 , wherein the protective film is formed on a top surface of the mask by the reaction product generated by the first plasma, and

the protective film is formed on a side surface of the mask and a side surface of the etching target film that is etched, by the reaction product generated by the third plasma.