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

• US 8,334,657 B2
• Filed: 01/10/2011
• Issued: 12/18/2012
• Est. Priority Date: 08/05/2005
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Advanced Micro-Fabrication Equipment Inc., Applied Materials Incorporated
• Inventors: Xia, Yaomin
• Primary Examiner(s): Le, Tung X
• Application Number:
  US12/987,538
• Publication Number:
  US 20110309748A1
• Time in Patent Office: 708 Days
• Field of Search: 31511121-11181, 156/345.28, 156/45.43, 156/345.44, 156/345.47
• US Class Current: 315/111.51
• 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. An RF matching network comprising:

a set of n RF input ports, each port adapted to be connected to one of a set of RF generators, each RF generator generating at least one frequency that is different from frequencies of other RF generators in the set;

an output port in electrical communication with a vacuum processing chamber; and

a set of n match circuits, each match circuit being connected to the output port and to one of the n RF input ports,

wherein each match circuit has a high output impedance with respect to all RF generator frequencies other than one frequency of the RF generator to which the match circuit is adapted to be connected, and

wherein at least one match circuit comprises a multi-spacing inductor having first and second clearances between wires of the inductor, the first clearance being different from the second clearance.

2. The RF matching network of claim 1, wherein the at least one match circuit further comprises a capacitor and a grounding capacitor, and no other electrical elements.

3. The RF matching network of claim 2, wherein the capacitor is in series with the inductor, and further electrically coupled in series with the grounding capacitor.

4. The RF matching network of claim 3, wherein the grounding capacitor is a fully or partially variable capacitor.

5. The RF matching network of claim 3, wherein the capacitor and the grounding capacitor are fully or partially variable capacitors.

6. The RF matching network of claim 2, wherein, between two neighboring frequencies, the ratio of the high frequency to the low frequency is greater than or equal to five.

7. The RF matching network of claim 1, wherein the first clearance is at an end of the inductor closer to the output port than an opposite end which is closer to the corresponding RF input port, and the first clearance is greater than the second clearance.

8. The RF matching network of claim 1, wherein, between two neighboring frequencies, the ratio of the high frequency to the low frequency is equal to or greater than about five.

9. The RF matching network of claim 1, wherein each match circuit further comprises a capacitor and a grounding capacitor.

10. The RF matching network of claim 1, wherein an i^th match circuit, when connected to the RF generator with the i^th frequency and when measuring from the output port to the i^th match circuit, has a first impedance at the i^th frequency, and wherein when measuring from the output port, and in the opposite direction to the i^th match circuit, the i^th match circuit has a second impedance at the i^th frequency, and wherein the first impedance is a substantial conjugate match of the second impedance.

11. The RF matching network of claim 1, wherein n is an integer greater than or equal to two.

12. The RF matching network of claim 1, wherein at least one match circuit comprises a capacitor, an inductor, and a grounding capacitor, and no other electrical elements.

13. The RF matching network of claim 1, wherein two RF input ports are both adapted to be connected to one RF generator, that RF generator generating two different RF frequencies to be supplied to the two RF input ports, respectively.

14. A method for supplying RF energy to a vacuum processing chamber, the method 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 energy produced by the respective RF generators to a vacuum processing chamber, wherein the first frequency is higher than the second frequency;

providing a first circuit located between the first frequency RF input and the output port, and which is further connected to the first frequency RF generator,

wherein the first circuit has high output impedance with respect to the second frequency; and

providing a second circuit between the second frequency RF input and the output port, and which is further connected to the second frequency RF generator,

wherein the second circuit has a high output impedance with respect to the first frequency, and

wherein the second circuit comprises a multi-spacing inductor having first and second clearances between wires of the inductor, the first clearance being different from the second clearance.

15. The method of claim 14, wherein a ratio between the first frequency and the second frequency is greater than or equal to five.

16. The method of claim 14, wherein the first circuit comprises a first capacitor, an inductor, and a first grounding capacitor, and no other electrical elements, and the second circuit comprises a second capacitor and a second grounding capacitor in addition to the multi-spacing inductor, and no other electrical elements.

17. The method of claim 16, wherein the first clearance is at an end closer to the output port than at an opposite end closer to the second frequency RF input port, and the first clearance is greater than the second clearance.

18. The method of claim 14, wherein, at least one of the first and second capacitors and the first and second grounding capacitors is a fully or partially variable capacitor.

19. The method of claim 14, further comprising:

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

20. The method of claim 14, wherein the vacuum processing chamber is a plasma deposition chamber.

21. The method of claim 14, wherein the vacuum processing chamber is a plasma etching chamber.

22. An RF matching network comprising:

a plurality of n RF generators, each RF generator having a different frequency;

a set of n RF input ports, each port being connected to one of the RF generators;

an output port in electrical communication with a vacuum processing chamber; and

a set of n match circuits, each match circuit being connected to the output port and to one of the n RF input ports,

wherein each match circuit has a high output impedance with respect to all RF generator frequencies other than the frequency of the RF generator to which the match circuit is connected, and

wherein at least one match circuit comprises;

(i) a conducting piece connected directly to the respective RF input port, and (ii) a variable capacitor connected directly to and in series with both the conducting piece and the input port.

23. An RF matching network comprising:

a set of n match circuits, each match circuit comprising;

(i) an input port adapted for electrical communication with an RF generator, and (ii) an output port adapted for electrical communication with a vacuum processing chamber,

wherein each match circuit has a high output impedance with respect to a distinct set of (n−

1) RF generator frequencies, and

wherein at least one match circuit comprises an inductor having first and second clearances between wires of the inductor, the first clearance being different from the second clearance.