Plasma processing method and apparatus

• US 20070281478A1
• Filed: 08/11/2006
• Published: 12/06/2007
• Est. Priority Date: 05/31/2006
• Status: Active Grant

• Current Assignee: Hitachi High-Technologies Corporation (Hitachi, Ltd.)
• Original Assignee: Hitachi High-Technologies Corporation (Hitachi, Ltd.)
• Inventors: Ikegami, Eiji, Ikuhara, Shoji, Shimada, Takeshi, Kuwabara, Kenichi, Arase, Takao, Matsumoto, Tsuyoshi
• Granted Patent: US 8,038,896 B2
• Time in Patent Office: Days
• US Class Current: 438/689
• CPC Class Codes: H01J 2237/1825 Evacuating means
• CPC Class Codes: H01J 2237/327 Arrangements for generating the plasma
• CPC Class Codes: H01J 37/32082 Radio frequency generated discharge H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/3211 Antennas, e.g. particular shapes of coils
• CPC Class Codes: H01J 37/32192 Microwave generated discharge H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence
• CPC Class Codes: H01J 37/32917 Plasma diagnostics
• CPC Class Codes: H01J 37/32926 Software, data control or modelling
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H01J 37/32963 End-point detection
• CPC Class Codes: H01J 37/32981 Gas analysis
• CPC Class Codes: H01J 37/3299 Feedback systems
• CPC Class Codes: H01L 21/67069 for drying etching
• CPC Class Codes: H01L 21/67242 Apparatus for monitoring, sorting or marking testing or measuring during manufacture H01L22/00, marks per se H01L23/544; testing individual semiconductor devices G01R31/26
• CPC Class Codes: H05H 1/46 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence

Abstract

Plasma processing of plural substrates is performed in a plasma processing apparatus, which is provided with a plasma processing chamber having an antenna electrode and a lower electrode for placing and retaining the plural substrates in turn within the plasma processing chamber, a gas feeder for feeding processing gas into the processing chamber, a vacuum pump for discharging gas from the processing chamber via a vacuum valve, and a solenoid coil for forming a magnetic field within the processing chamber. At least one of the plural substrates is placed on the lower electrode, and the processing gas is fed into the processing chamber. RF power is fed to the antenna electrode via a matching network to produce a plasma within the processing chamber in which a magnetic field has been formed by the solenoid coil. This placing of at least one substrate and this feeding of the processing gas are then repeated until the plasma processing of all of the plural substrates is completed. An end of seasoning is determined when a parameter including an internal pressure of the processing chamber has become stable to a steady value with plasma processing time.

Claims

1. A plasma processing method for performing plasma processing of plural substrates in a plasma processing apparatus, which is provided with:

a plasma processing chamber having an antenna electrode and a lower electrode for placing and retaining said plural substrates in turn within said plasma processing chamber,

a gas feeder for feeding processing gas into said processing chamber,

a vacuum pump for discharging gas from said processing chamber via a vacuum valve, and

a solenoid coil for forming a magnetic field within said processing chamber,

by placing at least one of said plural substrates on said lower electrode, feeding said processing gas into said processing chamber, feeding RF power to said antenna electrode via a matching network to produce a plasma within said processing chamber, in which a magnetic field has been formed by said solenoid coil, and repeating said placing and said feeding of said processing gas until said plasma processing of all of said plural substrates is completed,

wherein an end of seasoning is determined when a parameter comprising an internal pressure of said processing chamber has become stable to a steady value with plasma processing time.

2. A plasma processing method according to claim 1, wherein an emission intensity ratio (C₂/H) between carbon (C₂) and hydrogen (H) in said plasma is monitored as said parameter in a course of said plasma processing, and said end of said seasoning is determined when said emission intensity ratio has decreased to a steady value with plasma processing time.

3. A plasma processing method according to claim 1, wherein a peak-to-peak voltage of a RF bias to be fed to said lower electrode is monitored as said parameter in a course of said plasma processing, and said end of said seasoning discharge is determined when said peak-to-peak voltage has risen to a steady value with plasma processing time.

4. A plasma processing method according to claim 1, wherein an opening of said vacuum valve is monitored as said parameter in a course of said plasma processing, and said end of said seasoning discharge is determined when said opening of said vacuum valve has decreased to a steady value with plasma processing time.

5. A plasma processing method according to claim 1, wherein a time required to have an internal pressure of said processing chamber reduced to a predetermined vacuum pressure after completion of each plasma discharge is monitored as said parameter in a course of said plasma processing, and said end of said seasoning discharge is determined when said time has decreased to a steady value with plasma processing time.

6. A plasma processing method according to claim 1, wherein a matching electrostatic capacitance of a capacitor, which is a component of said matching network, is monitored as said parameter in a course of said plasma processing, and said end of said seasoning discharge is determined when said capacitance has increased to a steady value with plasma processing time.

7. A plasma processing method according to claim 1, wherein a time required until ignition of said plasma from said feeding of said RF power to said antenna electrode via said matching network is monitored as said parameter in a course of said plasma processing, and said end of said seasoning discharge is determined when said time has decreased to a steady value with plasma processing time.

8. A plasma processing method according to claim 1, wherein an electrostatic chuck voltage to be fed to said lower electrode is monitored as said parameter in a course of said plasma processing, and said end of said seasoning discharge is determined when with plasma processing time, scattering of said electrostatic chuck voltage has decreased and said electrostatic chuck voltage has increased to a steady value.

9. A plasma processing method according to claim 1, wherein a flow rate of heat transfer gas to be fed between said lower electrode and said at least one substrate placed on said lower electrode is monitored as said parameter in a course of said plasma processing, and said end of said seasoning discharge is determined when said flow rate has decreased to a steady value with plasma processing time.

10. A plasma processing method according to claim 1, wherein said end of said seasoning discharge is determined when in a course of said plasma processing, plural ones of the following conditions (1) to (8) have been met:

(1) an emission intensity ratio (C₂/H) between carbon (C₂) and hydrogen (H) in said plasma has decreased to a steady value with plasma processing time,

(2) a peak-to-peak voltage of a RF bias to be fed to said lower electrode has risen to a steady value with plasma processing time,

(3) an opening of said vacuum valve has decreased to a steady value with plasma processing time,

(4) a time required to have an internal pressure of said processing chamber reduced to a predetermined vacuum pressure after completion of each plasma discharge has decreased to a steady value with plasma processing time,

(5) a matching electrostatic capacitance of a capacitor, which is a component of said matching network, has increased to a steady value with plasma processing time,

(6) a time required until ignition of said plasma from said feeding of said RF power to said antenna electrode via said matching network has decreased to a steady value with plasma processing time,

(7) with plasma processing time, scattering of an electrostatic chuck voltage to be fed to said lower electrode has decreased and said electrostatic chuck voltage has increased to a steady value, and

(8) a flow rate of heat transfer gas to be fed between said lower electrode and said at least one substrate placed on said lower electrode has decreased to a steady value with plasma processing time.

11. A plasma processing apparatus provided with:

a plasma processing chamber having an antenna electrode and a lower electrode for placing and retaining said plural substrates in turn within said plasma processing chamber,

a gas feeder for feeding processing gas into said processing chamber,

a vacuum pump for discharging gas from said processing chamber via a vacuum valve, and

a solenoid coil for forming a magnetic field within said processing chamber,

for conducting plasma processing of said plural substrates by reassembling said processing chamber, placing at least one of said plural substrates on said lower electrode, feeding said processing gas into said processing chamber, feeding RF power to said antenna electrode via a matching network to produce a plasma within said processing chamber, in which a magnetic field has been formed by said solenoid coil, and repeating said placing and said feeding of said processing gas until said plasma processing of all of said plural substrates is completed,

wherein said plasma processing apparatus further comprises a sensor for monitoring, with time, changes in a parameter comprising an internal pressure of said processing chamber in a state of plasma production and a computing unit for determining an end of seasoning in said plasma processing apparatus on a basis of said changes with time, and said computing unit determines said end of said seasoning when said internal pressure of said processing chamber has fallen to a steady value with plasma processing time.

12. A plasma processing apparatus according to claim 11, wherein said sensor monitors, with time, reductions in said internal pressure of said processing chamber on a basis of reductions in an opening of said vacuum valve.

13. A plasma processing apparatus according to claim 11, wherein said sensor monitors, with time, reductions in said internal pressure of said processing chamber on a basis of decreases in a vacuuming time required until a predetermined vacuum pressure is reached.