Silicon scavenger in an inductively coupled RF plasma reactor

• US 5,556,501 A
• Filed: 04/01/1993
• Issued: 09/17/1996
• Est. Priority Date: 10/03/1989
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Lei, Lawrence C., Wong, Jerry Y., Collins, Kenneth S., Ishikawa, Tetsuya, Yang, Chan-Lon, Marks, Jeffrey, Toshima, Masato M., Pinson, Jay D. II, Roderick, Craig A., Trow, John R., Groechel, David W., Keswick, Peter R., Yin, Gerald Z.
• Primary Examiner(s): NGUYEN, NAM X
• Application Number:
  US08/041,796
• Time in Patent Office: 1,265 Days
• Field of Search: 204/298.16, 204/298.37, 204/298.34, 204/298.38, 204/298.08, 204/298.11, 204/298.31, 156/345, 315/111.21, 315/111.41, 315/111.51, 118/723 R, 118/621
• US Class Current: 156/345.38
• CPC Class Codes: C23C 16/509 using internal electrodes
• CPC Class Codes: H01F 2029/143 with control winding for generating magnetic bias
• 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 37/32146 Amplitude modulation, includes pulsing
• CPC Class Codes: H01J 37/32165 Plural frequencies
• CPC Class Codes: H01J 37/32174 Circuits specially adapted for controlling the RF discharge
• CPC Class Codes: H01J 37/3222 Antennas
• CPC Class Codes: H01J 37/32293 using particular waveforms, e.g. polarised waves
• CPC Class Codes: H01J 37/32458 Vessel
• CPC Class Codes: H01J 37/32522 Temperature
• CPC Class Codes: H01J 37/3266 Magnetic control means
• CPC Class Codes: H01J 37/32688 Multi-cusp fields
• CPC Class Codes: H01J 37/32706 Polarising the substrate
• CPC Class Codes: H01J 37/32871 Means for trapping or directing unwanted particles
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H05H 1/46 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence

Abstract

A domed plasma reactor chamber uses an antenna driven by RF energy (LF, MF, or VHF) which is inductively coupled inside the reactor dome. The antenna generates a high density, low energy plasma inside the chamber for etching metals, dielectrics and semiconductor materials. Auxiliary RF bias energy applied to the wafer support cathode controls the cathode sheath voltage and controls the ion energy independent of density. Various magnetic and voltage processing enhancement techniques are disclosed, along with etch processes, deposition processes and combined etch/deposition processed. The disclosed invention provides processing of sensitive devices without damage and without microloading, thus providing increased yields.

Claims

1. An RF plasma processing apparatus for processing of workpieces comprising:

a) a vacuum chamber in which a plasma is generated;

b ) a workpiece support member adapted for supporting workpieces to be processed within the chamber;

c) a gas inlet mounted in the chamber for supplying a plasma precursor processing gas to the chamber;

d) RF power source means for supplying first and second RF power signals;

e) a coil antenna coupling RF energy from the first RF power signal into the chamber so as to form a high density plasma from said processing gas;

f) a cathode electrode below or part of the workpiece support member electrically coupled to the second RF power signal so as to create an electric field which assists in attracting charged particles from the plasma toward the cathode electrode; and

g) a second electrode disposed above said cathode electrode and comprising silicon for chemically interacting with components of said processing gas;

wherein said second electrode is controllably heated to increase its reactivity.

2. An RF plasma processing apparatus according to claim 1 wherein said second electrode is in contact with the plasma.

3. An RF plasma processing apparatus according to claim 1 wherein said second electrode is coupled through the plasma to the RF power source.

4. An RF plasma processing apparatus according to claim 1 wherein the first RF power signal has a frequency in the range of about 300 kHz to about 3 MHz.

5. An RF plasma processing apparatus according to claim 1 wherein the second RF power signal has a frequency in the range of about 300 kHz to about 3 MHz.

6. The apparatus of claim 1, wherein said RF power source means supplies a third RF signal to said second electrode.

7. The apparatus of claim 1, wherein said second electrode is grounded.

8. An RF plasma processing apparatus according to claim 1, wherein said coil antenna comprises one or more turns in a spiral arrangement.

9. An RF plasma processing apparatus according to claim 8, wherein said solid source of silicon is an electrode.

10. An RF plasma processing apparatus according to claim 9, wherein said RF power source means supplies a third RF signal to said electrode which is a solid source of silicon.

11. An RF plasma processing apparatus for processing of workpieces comprising:

a) a vacuum chamber in which a plasma is generated;

b) a workpiece support member adapted for supporting workpieces to be processed within the chamber;

c) a gas inlet mounted in the chamber for supplying a plasma precursor processing gas to the chamber;

d) RF power source means for supplying first and second RF power signals;

e) a coil antenna coupling RF energy from the first RF power signal into the chamber so as to form a high density plasma from said processing gas;

f) a cathode electrode below or part of the workpiece support member electrically coupled to the second RF power signal so as to create an electric field which assists in attracting charged particles from the plasma toward the cathode electrode; and

g) a solid source of silicon in the chamber apart from said workpieces being processed and from said workpiece support for chemically interacting with components of said processing gas;

wherein said vacuum chamber includes a top chamber portion enclosing a space overlying said workpiece support member and having a controllably heated dielectric wall through which said coil antenna couples said RF energy into said chamber.

12. The apparatus of claim 11, further including heating means for controllably heating said dielectric wall.

13. An RF plasma processing apparatus for processing of workpieces comprising:

a) a vacuum chamber in which a plasma is generated;

b) a workpiece support member adapted for supporting workpieces to be processed within the chamber;

c) a gas inlet mounted in the chamber for supplying a plasma precursor processing gas to the chamber;

d) RF power source means for supplying first and second RF power signals;

e) a coil antenna coupling RF energy from the first RF power signal into the chamber so as to form a high density plasma from said processing gas;

f) a cathode electrode below or part of the workpiece support member electrically coupled to the second RF power signal so as to create an electric field which assists in attracting charged particles from the plasma toward the cathode electrode; and

g) a solid source of silicon in the chamber apart from said workpieces being processed and from said workpiece support for chemically interacting with components of said processing gas;

wherein said solid source of silicon is disposed in a space overlying said workpiece support member and supported in a controllably heated portion of said vacuum chamber.

14. The apparatus of claim 13, further including heating means for controllably heating said heated portion.

15. An RF plasma processing apparatus according to claim 13, wherein said coil antenna is disposed intermediate between said workpiece support member and said solid source of silicon.