PLASMA PROCESSING APPARATUS AND PLASMA PROCESSING METHOD

• US 20140148016A1
• Filed: 01/25/2013
• Published: 05/29/2014
• Est. Priority Date: 11/27/2012
• Status: Active Grant

• Current Assignee: Hitachi High-Tech Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi High-Technologies Corporation (Hitachi, Ltd.)
• Inventors: Yasui, Naoki, Morimoto, Michikazu, Kanazawa, Shunsuke, Ohgoshi, Yasuo
• Granted Patent: US 8,992,724 B2
• Time in Patent Office: Days
• US Class Current: 438/714
• CPC Class Codes: C23F 4/00 Processes for removing metallic material from surfaces, not provided for in group C23F1/00 or C23F3/00
• CPC Class Codes: H01J 37/32146 Amplitude modulation, includes pulsing
• CPC Class Codes: H01J 37/32155 Frequency modulation
• CPC Class Codes: H01J 37/32165 Plural frequencies
• CPC Class Codes: H01J 37/32302 Plural frequencies
• CPC Class Codes: H01J 37/32311 Circuits specially adapted for controlling the microwave discharge
• CPC Class Codes: H01L 21/32137 of silicon-containing layers

Abstract

A plasma processing apparatus includes a processing chamber which plasma-processes a sample, a first high-frequency power supply which supplies first high-frequency power for plasma generation to the processing chamber, a second high-frequency power supply which supplies second high-frequency power to a sample stage on which the sample is placed and a pulse generation device which generate first pulses for time-modulating the first high-frequency power and second pulses for time-modulating the second high-frequency power. The pulse generation device includes a control device which controls the first and second pulses so that frequency of the first pulses is higher than frequency of the second pulses and the on-period of the second pulse is contained in the on-period of the first pulse.

Claims

1. A plasma processing apparatus comprising:

a processing chamber which plasma-processes a sample;

a first high-frequency power supply which supplies first high-frequency power for plasma generation to the processing chamber;

a second high-frequency power supply which supplies second high-frequency power to a sample stage on which the sample is placed; and

a pulse generation device which generates first pulses to time-modulate the first high-frequency power and second pulses to time-modulate the second high-frequency power, wherein

the pulse generation device includes a control device which controls the first and second pulses so that a frequency of the first pulses is higher than a frequency of the second pulses and an on-period of the second pulse is contained in an on-period of the first pulse.

2. The plasma processing apparatus according to claim 1, wherein

the frequency of the first pulses is a frequency at which afterglow discharge can be maintained.

3. The plasma processing apparatus according to claim 1, wherein

the on-period of the second pulse is shorter than the on-period of the first pulse.

4. The plasma processing apparatus according to claim 3, wherein

the on-period of the second pulse is delayed as compared with the on-time of the first pulse.

5. The plasma processing apparatus according to claim 1, wherein

the pulse generation device monitors a peak-to-peak voltage Vpp of a high-frequency voltage applied to the sample stage from the second high-frequency power supply and, when the monitored Vpp is higher than a predetermined value, increases the frequency of the first pulses to make the monitored Vpp lower than the predetermined value.

6. A plasma processing method of plasma-processing a sample using a plasma processing apparatus which includes a processing chamber to plasma-process the sample, a first high-frequency power supply configured to supply first high-frequency power for plasma generation to the processing chamber, a second high-frequency power supply configured to supply second high-frequency power to a sample stage on which the sample is placed and a pulse generation device configured to generate first pulses to time-modulate the first high-frequency power and second pulses to time-modulate the second high-frequency power, the method comprising the step of:

plasma-processing the sample while the high-frequency power time-modulated by the second pulses is supplied to the sample stage using the plasma time-modulated by the first pulses,

and wherein

a frequency of the first pulses is made higher than a frequency of the second pulses and an on-period of the second pulse is made to be contained in an on-period of the first pulse.

7. The plasma processing method according to claim 6, wherein

the frequency of the first pulses is a frequency at which afterglow discharge can be maintained.

8. The plasma processing method according to claim 6, wherein

the on-period of the second pulse is shorter than the on-period of the first pulse.

9. The plasma processing method according to claim 8, wherein

the on-period of the second pulse is delayed as compared with the on-time of the first pulse.

10. The plasma processing method according to claim 6, wherein

a peak-to-peak voltage Vpp of a high-frequency voltage applied to the sample stage from the second high-frequency power supply is monitored by the pulse generation device and when the monitored Vpp is higher than a predetermined value, the frequency of the first pulses is increased to make the monitored Vpp lower than the predetermined value.