RF matching network of a vacuum processing chamber and corresponding configuration methods

• US 7,868,556 B2
• Filed: 02/08/2006
• Issued: 01/11/2011
• Est. Priority Date: 08/05/2005
• Status: Active Grant

• Current Assignee: Advanced Micro-Fabrication Equipment Inc.
• Original Assignee: Advanced Micro-Fabrication Equipment Inc.
• Inventors: Xia, Yaomin
• Primary Examiner(s): Owens; Douglas W
• Assistant Examiner(s): Le; Tung X
• Application Number:
  US11/350,022
• Publication Number:
  US 20070030091A1
• Time in Patent Office: 1,798 Days
• Field of Search: 31511101-11191, 156/345.28, 156/345.43, 156/345.44, 156/345.47
• 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 7/40 Automatic matching of load impedance to source impedance
• CPC Class Codes: H05H 1/46 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence

Abstract

A RF matching network is described, and which includes a 1^st to nth RF generators, and wherein each RF generator has a different frequency, and wherein the frequencies of the 1^st to the nth RF input ports decline in sequence, and wherein between the ith frequency RF input port, and the output port is a ith circuit, which has a high impedance at the output port to all RF generator frequencies other than the ith frequency; and wherein the ith circuit, when connected to a RF generator with the ith frequency, and wherein measuring from the output port to the ith circuit, the ith circuit has a first impedance at the ith frequency; and when measuring from the output port in the opposite direction to the ith circuit, the ith circuit has a second impedance at the ith frequency; and wherein the first impedance is a substantial conjugate match of the second impedance.

Claims

1. A RF matching network comprising:

1^st to nth RF input ports connected respectively with a 1^st to nth RF generator, and wherein each RF generator has a different frequency, and an output port that outputs energy of the respective RF generators to a vacuum processing chamber, and wherein the frequencies of the 1^st to the nth RF input ports decline in sequence; and

wherein

between the ith frequency RF input port, and the output port is an ith circuit, and wherein the ith circuit has a high impedance at the output port to all RF generator frequencies other than the ith frequency; and

wherein

the ith circuit, when connected to the RF generator with the ith frequency, and when measuring from the output port to the ith circuit, has a first impedance at the ith frequency; and

wherein when measuring from the output port, and in the opposite direction to the ith circuit, the ith circuit has a second impedance at the ith frequency; and

wherein the first impedance is a substantial conjugate match of the second impedance.

2. The RF matching network as claimed in claim 1, and wherein between two neighboring frequencies, the ratio of the high frequency to the low frequency is equal to or greater than 5.

3. The RF matching network as claimed in claim 1, and wherein each of the circuits consists essentially of a capacitor;

an inductor; and

a grounding capacitor, and wherein the capacitor is in series with the inductor, and further coupled in series with the grounding capacitor.

4. The RF matching network as claimed in claim 3, and wherein the capacitor and the grounding capacitor are fully or partially variable capacitors.

5. The RF matching network as claimed in claim 3, and wherein the electrical connection of each of the circuits can be L-type, inverse-L type, T-type, or π

-type.

6. The RF matching network as claimed in claim 1, and wherein n is an integer larger than or equal to 2, i is an integer which is not less than 2, and no larger than n.

7. The RF matching network as claimed in claim 1, and wherein the vacuum processing chamber is a plasma deposition chamber.

8. The RF matching network as claimed in claim 1, and wherein the vacuum processing chamber is a plasma etching chamber.

9. A RF matching network comprising:

a first frequency RF input port connected to a first frequency RF generator;

a second frequency RF input port connected to a second frequency RF generator; and

an output port that outputs the energy of one of both of the RF generators to a vacuum processing chamber, and wherein the first frequency is higher than the second frequency; and

wherein between the first frequency RF input port, and the output port is a first circuit which has a high impedance relative to the output port at the second frequency; and

wherein between the second frequency RF input port and the output port is a second circuit, which has high impedance relative to the output port at the first frequency, and wherein the first circuit, when connected to the first frequency RF generator, and when measuring from the output port to the first circuit, has a first impedance at the ith frequency, and further when measuring from the output port in the opposite direction to the first circuit, has a second impedance at the ith frequency, and wherein the first impedance is a substantial conjugate match of the second impedance.

10. The RF matching network as claimed in claim 9, and wherein the first circuit and the second circuit respectively comprise a capacitor;

an inductor; and

a grounding capacitor, and wherein the capacitor is in series with the inductor, and further electrically coupled in series with the grounding capacitor.

11. The RF matching network as claimed in claim 10, and wherein the capacitor and the grounding capacitor are fully or partially variable capacitors.

12. The RF matching network as claimed in claim 11, and wherein the electrical connection of each circuit is selected from the group comprising L-type, inverse-L type, T-type, or π

-type.

13. The RF matching network as claimed in claim 10, and wherein between the output port of the first circuit, and the vacuum processing chamber, a conducting connector having an end tip is connected in series, and wherein the end tip can be a connection of one or multiple branches to the lower electrode of the vacuum processing chamber.

14. The RF matching network as claimed in claim 10, and wherein wires forming the inductor are spaced apart, and wherein the space between the wires of the inductor of the second circuit is larger at the end of the inductor which is closest to the output port than at the end which is closest to the second frequency RF input port.

15. The RF matching network as claimed in claim 9, and wherein the ratio between the first frequency and the second frequency is larger than or equal to 5.

16. The RF matching network as claimed in claim 9, and wherein the vacuum processing chamber is a plasma deposition chamber.

17. The RF matching network as claimed in claim 9, and wherein the vacuum processing chamber is a plasma etching chamber.

18. A method for supplying RF energy to a vacuum processing chamber, comprising:

connecting a first frequency RF input port to a first frequency RF generator;

connecting a second frequency RF input port to a second frequency RF generator;

providing an output port that outputs the energy produced by the respective RF generators to the vacuum processing chamber, and wherein the first frequency is higher than the second frequency;

providing a first circuit which is located between the first frequency RF input and the output port, and wherein the first circuit has high impedance relative to the output port at the second frequency, and which is further connected to the first frequency RF generator;

providing a second circuit between the second frequency RF input port, and the output port, and wherein the second circuit has a high impedance relative to the output port at the first frequency;

measuring a first impedance at an ith frequency from the output port to the first circuit; and

measuring a second impedance at the ith frequency from the output port in the opposite direction to the first circuit, and wherein the first impedance is substantially a conjugate match of the second impedance.

19. The method as claimed in claim 18, and wherein the first circuit and the second circuit each comprise a capacitor;

an inductor; and

a grounding capacitor, and wherein the capacitor is in series with the inductor; and

further connected in series with the grounding capacitor.

20. The method as claimed in claim 19, and wherein the capacitor and the grounding capacitor are fully or partially variable capacitors.

21. The method as claimed in claim 20, and wherein the electrical connection of the each circuit can be L-type, inverse-L type, T-type, or π

-type.

22. The method as claimed in claim 19, and further comprising:

providing a conducting connector which is coupled with the vacuum processing chamber; and

wherein between the output port of the first circuit and the vacuum processing chamber, the conducting connector is connected in series, and wherein the end tip of the conducting connector can be a connection of one or multiple branches to a lower electrode of the vacuum processing chamber.

23. The method as claimed in claim 19, and wherein the inductor has spaced wires, and wherein the clearance between the wires of the inductor of the second circuit is larger at an end closest to the output port than at an opposite end which is closest to the second frequency RF input port.

24. The method as claimed in claim 18, and wherein the ratio between the first frequency and the second frequency is equal to or greater than 5.

25. The method as claimed in claim 18, and wherein the vacuum processing chamber is a plasma deposition chamber.

26. The method as claimed in claim 18, and wherein the vacuum processing chamber is a plasma etching chamber.

27. A RF matching network, comprising:

a first and a second RF generator which each produce RF energy having a different frequency, and wherein each RF generator supplies the RF energy to a processing chamber;

a first circuit coupling the first RF generator to the processing chamber, and which has a first high impedance relative to the frequency of RF energy provided by the second RF generator; and

a second circuit coupling the second RF generator to the processing chamber, and which has a second high impedance relative to the frequency of RF energy provided by the first RF generator, and wherein the first impedance is a substantially conjugate match of the second impedance.