Impedance matching network with termination of secondary RF frequencies

• US 6,888,313 B2
• Filed: 07/16/2003
• Issued: 05/03/2005
• Est. Priority Date: 07/16/2003
• Status: Active Grant

• Current Assignee: AES Global Holdings Pte Ltd. (Advanced Energy Industries, Inc. (China))
• Original Assignee: Advanced Energy Industries Incorporated
• Inventors: Mason, Christopher C., Blackburn, Thomas Joel
• Primary Examiner(s): Philogene, Haissa
• Application Number:
  US10/621,695
• Publication Number:
  US 20050011451A1
• Time in Patent Office: 657 Days
• Field of Search: 315/111.21, 315/111.51, 315/111.71, 324/652, 324/637, 324/633, 204/298.08, 204/298.34, 204/298.38, 219/121.36, 219/121.43, 156/345.44, 156/345.48, 118/723.E, 118/723.I
• US Class Current: 315/111.21
• 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 37/32183 Matching circuits
• CPC Class Codes: H03H 7/38 Impedance-matching networks
• CPC Class Codes: H05H 1/46 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence

Abstract

There is provided a secondary reactive termination circuit connected between the output of the RF power generator and the input of the plasma chamber to allow the tight regulation or limiting of the voltage and current components of the secondary frequencies within the process plasma. The secondary reactive circuit controls the impedance of the match network designed primarily to operate at the fundamental frequency of the RF power generator as seen by secondary frequencies in the system. A variable capacitor gives the operator the advantage of being able to tightly regulate the voltage, current, and power within a process at discrete frequencies without concern for impedance variability induced by other components in the system.

Claims

1. An RF power delivery system for plasma processing comprising:

a) an RF power generator disposed to deliver power to a plasma chamber for creating a plasma to deposit thin films on a substrate;

b) an impedance matching network connected to the output of the RF power generator to provide an efficient transfer of power from the RF power generator to the plasma in the chamber by matching the impedance of the plasma to the operating impedance of the generator; and

c) a secondary reactive termination circuit connected between the output of the RF power generator and the input of the plasma chamber to allow the tight regulation or limiting of the voltage and current components of secondary frequencies within the process plasma.

2. An RF power delivery system for plasma processing comprising as recited in claim 1 wherein the secondary reactive termination circuit is comprised a parallel connection of a first and second capacitor connected in parallel series connected to an inductor and a variable capacitor.

3. An RF power delivery system for plasma processing comprising as recited in claim 2 wherein the secondary reactive termination circuit controls the impedance of the matching network designed primarily to operate at the fundamental frequency of the RF power generator as seen by secondary frequencies in the system.

4. An RF power delivery system for plasma processing comprising as recited in claim 3 wherein a variable capacitor that allows tight regulation of the voltage, current, and power within a process at discrete frequencies without concern for impedance variability induced by other components in the system.