Close coupled match structure for RF drive electrode

• US 6,657,395 B2
• Filed: 02/12/2003
• Issued: 12/02/2003
• Est. Priority Date: 08/17/2000
• Status: Expired due to Fees

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Windhorn, Thomas H.
• Primary Examiner(s): VU, DAVID HUNG
• Application Number:
  US10/364,409
• Publication Number:
  US 20030141825A1
• Time in Patent Office: 293 Days
• Field of Search: 315/111.21, 315/111.51, 118/723.E, 118/723.I, 118/723.IR
• US Class Current: 315/111.21
• CPC Class Codes: H01J 2237/3323 uniformity
• 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 37/32183 Matching circuits

Abstract

An electrode assembly for supplying RF power from a RF power source having an output impedance to an electrically non-linear medium, the assembly being composed of: a drive electrode in communication with the medium and forming with the medium a load impedance; and an impedance match network coupled between the RF power source and the drive electrode for matching the output impedance of the RF source to the load impedance. The match network has an output component that is directly connected to the drive electrode. The electrode assembly can further have a body of RF energy absorbing material disposed between the match network and the drive electrode, the absorbing material having a frequency dependent energy absorption characteristic which increases with frequency.

Claims

1. An electrode assembly for supplying RF power from an RF power source having an output impedance to an electrically non-linear medium, said assembly comprising:

a drive electrode in communication with the medium and forming with the medium a load impedance; and

an impedance match network coupled between the RF power source and said drive electrode for matching the output impedance of the RF source to the load impedance, said match network having an output component that is directly connected, physically and electrically, to said drive electrode.

2. The electrode assembly of claim 1 further comprising a body of RF energy absorbing material disposed between said match network and said drive electrode, said absorbing material having a frequency dependent energy absorption characteristic which increases with frequency.

3. The electrode assembly of claim 2 wherein said absorbing material has relatively low absorption at the fundamental frequency of RF power and relatively higher absorption at harmonics of the fundamental frequency.

4. The electrode assembly of claim 2 wherein said body of RF energy absorbing material has a thickness of the order of one inch.

5. The electrode assembly of claim 4 wherein said absorbing material is an epoxy resin loaded with iron powder.

6. The electrode assembly of claim 1 wherein said output component of said match network is a capacitor having a conductive plate connected to said drive electrode.

7. The electrode assembly of claim 6 wherein said conductive plate has a cylindrical form.

8. A plasma reactor comprising a chamber enclosing a plasma region and an electrode assembly according to claim 1 disposed in said plasma region.

9. The reactor of claim 8 further comprising a wafer support constituting a second electrode disposed in said plasma region.

10. An electrode assembly for supplying RF power from an RF power source having an output impedance to an electrically non-linear medium, said assembly comprising:

a drive electrode in communication with the medium and forming with the medium a load impedance;

an impedance match network coupled between the RF power source and said drive electrode for matching the output impedance of the RF source to the load impedance; and

a body of RF energy absorbing material disposed between said match network and said drive electrode, said absorbing material having a frequency dependent energy absorption characteristic which increases with frequency.

11. The electrode assembly of claim 10 wherein said absorbing material has relatively low absorption at the fundamental frequency of RF power and relatively higher absorption at harmonics of the fundamental frequency.

12. The electrode assembly of claim 11 wherein said body of RF energy absorbing material has a thickness of the order of one inch.

13. The electrode assembly of claim 12 wherein said absorbing material is an epoxy resin loaded with iron powder.

14. A plasma reactor comprising a chamber enclosing a plasma region and an electrode assembly according to claim 10 disposed in said plasma region.

15. The reactor of claim 14 further comprising a wafer support constituting a second electrode disposed in said plasma region.