STATE-BASED ADJUSTMENT OF POWER AND FREQUENCY

• US 20130213573A1
• Filed: 09/14/2012
• Published: 08/22/2013
• Est. Priority Date: 02/22/2012
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Valcore, John C. Jr., Lyndaker, Bradford J.
• Granted Patent: US 9,197,196 B2
• Time in Patent Office: Days
• US Class Current: 156/345.28
• CPC Class Codes: H02J 3/00 Circuit arrangements for ac mains or ac distribution networks
• CPC Class Codes: H03J 7/00 Automatic frequency control; Automatic scanning over a band of frequencies
• CPC Class Codes: H05H 1/46 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence
• CPC Class Codes: H05H 1/4645 Radiofrequency discharges
• CPC Class Codes: H05H 2242/26 Matching networks

Abstract

Systems and methods for state-based adjustment of power and frequency are described. A primary generator of a system includes a primary power supply for supplying a primary radio frequency (RF) signal to an electrode. The primary generator further includes an automatic frequency control (AFC) to provide a first frequency input to the primary power supply when a pulsed signal is in a first state. A secondary generator of the system includes a secondary power supply for supplying a secondary RF signal to the electrode. The secondary generator also includes an AFC to provide a second frequency input to the secondary power supply when the pulsed signal is in the first state. The secondary generator includes an AFC to provide a third frequency input to the secondary power supply when the pulsed signal is in a second state. The system includes a digital pulsing source for generating the pulsed signal.

Claims

1. A system comprising:

a primary generator coupled to an electrode, the primary generator including a primary power supply for supplying a primary radio frequency (RF) signal to the electrode, the primary generator further including an automatic frequency control (AFC) to provide a first frequency input to the primary power supply when a pulsed signal is in a first state;

a secondary generator coupled to the electrode, the secondary generator including a secondary power supply for supplying a secondary RF signal to the electrode, the secondary generator including an AFC to provide a second frequency input to the secondary power supply when the pulsed signal is in the first state, the secondary generator including an AFC to provide a third frequency input to the secondary power supply when the pulsed signal is in a second state; and

a digital pulsing source for generating the pulsed signal.

2. The system of claim 1, wherein the secondary generator includes a selector to transfer the second frequency input that is received from a digital signal processor to the secondary power supply or the third frequency input that is received from the digital signal processor to the secondary power supply.

3. A system comprising:

a plasma chamber including a lower electrode with a surface for supporting a substrate and an upper electrode disposed over the lower electrode, the upper electrode being electrically grounded;

a primary generator coupled to the lower electrode, the primary generator including a primary power supply for supplying a primary radio frequency (RF) signal to the lower electrode;

a secondary generator coupled to the lower electrode, the secondary generator including a secondary power supply for supplying a secondary RF signal to the lower electrode;

a digital pulsing source for generating a pulsed signal, the digital pulsing source coupled to the primary generator and the secondary generator, wherein the pulsed signal transitions between two states,

the primary generator including a first automatic frequency control (AFC) to provide a first frequency input to the primary power supply when the pulsed signal is in the first state;

the secondary generator including a second AFC to provide a second frequency input to the secondary power supply when the pulsed signal is in the first state;

the secondary generator including a third AFC to provide a third frequency input to the secondary power supply when the pulsed signal is in the second state.

4. The system of claim 3, further comprising a selector coupled between the digital pulsing source and the second and third AFCs to select between the second AFC and the third AFC for providing the second frequency input or the third frequency input to the secondary power supply, the selector configured to select between the second AFC and the third AFC based on the states of the pulsed signal.

5. The system of claim 3, wherein one of the two states is an on state and another one of the two states is an off state.

6. The system of claim 3, wherein the primary RF signal has a lower frequency than the secondary RF signal.

7. The system of claim 3,

wherein the primary RF signal is at a first power level when the pulsed signal is in the first state and is at a second power level when the pulsed signal is in the second state, wherein the first power level is greater than the second power level,

wherein the secondary RF signal is at a third power level when the pulsed signal is in the first state and at a fourth power level when the pulsed signal is in the second state, the third power level is lower than the fourth power level.

8. The system of claim 7, wherein the third power level is zero or positive.

9. The system of claim 3,

wherein the primary RF signal is at a first power level when the pulsed signal is in the first state and is at a second power level when the pulsed signal is in the second state, wherein the first power level is greater than the second power level,

wherein the secondary RF signal is at a third power level when the pulsed signal is in the first state and at a fourth power level when the pulsed signal is in the second state, the third power level the same as the fourth power level.

10. The system of claim 9, wherein the third power level is positive.

11. The system of claim 3,

wherein the primary RF signal is at a first power level when the pulsed signal is in the first state and is at a second power level when the pulsed signal is in the second state, wherein the first power level is greater than the second power level,

wherein the secondary RF signal is at a third power level when the pulsed signal is in the first state and at a fourth power level when the pulsed signal is in the second state, the third power level is greater than the fourth power level.

12. The system of claim 11, wherein the third power level is zero or positive.

13. The system of claim 3, wherein the digital pulse source includes a clock oscillator or a transistor-transistor logic (TTL).

14. The system of claim 3, wherein the first frequency input is different from the second frequency input and the third frequency input.

15. The system of claim 3, wherein the select includes a multiplexer.

16. A system comprising:

a digital pulsing source for generating a pulsed signal;

a primary generator including;

a primary power supply coupled to an electrode for supplying a primary radio frequency (RF) signal to the electrode;

a primary processor coupled to the pulsing source for receiving the pulsed signal, the primary processor for identifying a first one of two states of the pulsed signal and a second one of the two states;

a power controller coupled to the primary processor to determine whether to provide a primary power value to the primary power supply based on whether the pulsed signal is in the first state or the second state; and

an automatic frequency control (AFC) coupled to the primary processor to receive the state identification from the primary processor, the AFC configured to provide a frequency of the primary RF signal when the pulsed signal is in the first state;

a secondary generator including;

a secondary power supply coupled to the electrode for supplying a secondary RF signal to the electrode;

a secondary processor coupled to the pulsing source for receiving the pulsed signal to identify whether the pulsed signal is in the first state or the second state;

a first power controller coupled to the secondary processor to provide a first secondary power value to the secondary power supply when the pulsed signal is in the first state;

a second power controller coupled to the secondary processor to provide a second secondary power value to the secondary power supply when the pulsed signal is in the second state;

a first AFC coupled to the secondary processor to receive the state identification from the secondary processor, the first AFC configured to provide a first frequency input of the secondary RF signal when the pulsed signal is in the first state; and

a second AFC coupled to the secondary processor to receive the state identification from the secondary processor, the second AFC configured to provide a second frequency input of the secondary RF signal when the pulsed signal is in the second state.

17. The system of claim 16, wherein the secondary generator includes a selector to transfer the first frequency input that is received from the secondary processor to the secondary power supply or the second frequency input that is received from the secondary processor to the secondary power supply.

18. A system comprising:

a plasma chamber including a lower electrode with a surface for supporting a substrate and an upper electrode disposed over the lower electrode, the upper electrode being electrically grounded;

a digital pulsing source for generating a pulsed signal, wherein the pulsed signal transitions between two states;

a primary generator including;

a primary power supply coupled to the lower electrode for supplying a primary radio frequency (RF) signal to the lower electrode;

a primary processor coupled to the pulsing source for receiving the pulsed signal, the primary processor for identifying a first one of the two states and a second one of the two states of the pulsed signal;

a power controller coupled to the primary processor to determine whether to provide a primary power value to the primary power supply based on whether the pulsed signal is in the first state or the second state; and

an automatic frequency control (AFC) coupled to the primary processor to receive the state identification from the primary processor, the AFC configured to provide a frequency of the primary RF signal when the pulsed signal is in the first state; and

a secondary generator including;

a secondary power supply coupled to the lower electrode for supplying a secondary RF signal to the lower electrode;

a secondary processor coupled to the pulsing source for receiving the pulsed signal to identify whether the pulsed signal is in the first state or the second state;

a first power controller coupled to the secondary processor to provide a first secondary power value to the secondary power supply when the pulsed signal is in the first state;

a second power controller coupled to the secondary processor to provide a second secondary power value to the secondary power supply when the pulsed signal is in the second state;

a first AFC coupled to the secondary processor to receive the state identification from the secondary processor, the first AFC configured to provide a frequency of the secondary RF signal when the pulsed signal is in the first state; and

a second AFC coupled to the secondary processor to receive the state identification from the secondary processor, the second AFC configured to provide a frequency of the secondary RF signal when the pulsed signal is in the second state.

19. The system of claim 18, wherein one of the two states is an on state and another one of the two states is an off state.

20. The system of claim 18,

wherein the primary RF signal is at a first power level when the pulsed signal is in the first state and is at a second power level when the pulsed signal is in the second state, wherein the first power level is greater than the second power level,

wherein the first secondary power value is lower than the second secondary power value.

21. The system of claim 18,

wherein the primary RF signal is at a first power level when the pulsed signal is in the first state and is at a second power level when the pulsed signal is in the second state, wherein the first power level is greater than the second power level,

wherein the first secondary power value is same as the second secondary power value.

22. The system of claim 18,

wherein the primary RF signal is at a first power level when the pulsed signal is in the first state and is at a second power level when the pulsed signal is in the second state, wherein the first power level is greater than the second power level,

wherein the first secondary power value is greater than the second secondary power value.

23. The system of claim 18, wherein the primary power value is a positive power value when the pulsed signal is in the first state.

24. The system of claim 18, wherein the first secondary power value is lower than, same as, or greater than the second secondary power value.

25. A system comprising:

a digital pulsing source for generating a pulsed signal;

a primary generator including;

a primary power supply coupled to an electrode for supplying a primary radio frequency (RF) signal to the electrode;

a primary processor coupled to the pulsing source for receiving the pulsed signal, the primary processor for identifying a first one of two states of the pulsed signal and a second one of the two states;

a first primary power controller coupled to the primary processor to provide a first primary power value to the primary power supply when the pulsed signal is in the first state;

a second primary power controller coupled to the primary processor to provide a second primary power value to the primary power supply when the pulsed signal is in the second state;

a first primary automatic frequency control (AFC) coupled to the primary processor to receive the state identification from the primary processor, the first AFC configured to provide a first primary frequency input to the primary RF signal when the pulsed signal is in the first state; and

a second primary AFC coupled to the primary processor to receive the state identification from the primary processor, the second primary AFC configured to provide a second primary frequency input to the primary RF signal when the pulsed signal is in the second state;

a secondary generator including;

a secondary power supply coupled to the electrode for supplying a secondary RF signal to the electrode;

a secondary processor coupled to the pulsing source for receiving the pulsed signal to identify whether the pulsed signal is in the first state or the second state;

a first secondary power controller coupled to the secondary processor to provide a first secondary power value to the secondary power supply when the pulsed signal is in the first state;

a second secondary power controller coupled to the secondary processor to provide a second secondary power value to the secondary power supply when the pulsed signal is in the second state;

a first secondary AFC coupled to the secondary processor to receive the state identification from the secondary processor, the first secondary AFC configured to provide a first secondary frequency input to the secondary RF signal when the pulsed signal is in the first state; and

a second secondary AFC coupled to the secondary processor to receive the state identification from the secondary processor, the second secondary AFC configured to provide a second secondary frequency input to the secondary RF signal when the pulsed signal is in the second state.

26. The system of claim 25, wherein the primary generator includes a selector, the selector configured to transfer the first primary frequency input that is received from the primary processor to the primary power supply or the second primary frequency input that is received from the secondary processor to the primary power supply,

wherein the secondary generator includes a selector, the selector configured to transfer the first secondary frequency input that is received from the secondary processor to the secondary power supply or the second secondary frequency input that is received from the secondary processor to the secondary power supply.

27. A system comprising:

a plasma chamber including a lower electrode with a surface for supporting a substrate and an upper electrode disposed over the lower electrode, the upper electrode being electrically grounded;

a digital pulsing source for generating a pulsed signal, wherein the pulsed signal transitions between two states;

a primary generator including;

a primary power supply coupled to the lower electrode for supplying a primary radio frequency (RF) signal to the lower electrode;

a primary processor coupled to the pulsing source for receiving the pulsed signal, the primary processor for identifying a first one of the two states and a second one of the two states of the pulsed signal;

a first primary power controller coupled to the primary processor to provide a first primary power value to the primary power supply when the pulsed signal is in the first state;

a second primary power controller coupled to the primary processor to provide a second primary power value to the primary power supply when the pulsed signal is in the second state;

a first primary automatic frequency control (AFC) coupled to the primary processor to receive the state identification from the primary processor, the first AFC configured to provide a frequency of the primary RF signal when the pulsed signal is in the first state; and

a second primary AFC coupled to the primary processor to receive the state identification from the primary processor, the second primary AFC configured to provide a frequency of the primary RF signal when the pulsed signal is in the second state; and

a secondary generator including;

a secondary power supply coupled to the lower electrode for supplying a secondary RF signal to the lower electrode;

a secondary processor coupled to the pulsing source for receiving the pulsed signal to identify whether the pulsed signal is in the first state or the second state;

a first secondary power controller coupled to the secondary processor to provide a first secondary power value to the secondary power supply when the pulsed signal is in the first state;

a second secondary power controller coupled to the secondary processor to provide a second secondary power value to the secondary power supply when the pulsed signal is in the second state;

a first secondary AFC coupled to the secondary processor to receive the state identification from the secondary processor, the first secondary AFC configured to provide a frequency of the secondary RF signal when the pulsed signal is in the first state; and

a second secondary AFC coupled to the secondary processor to receive the state identification from the secondary processor, the second secondary AFC configured to provide a frequency of the secondary RF signal when the pulsed signal is in the second state.

28. The system of claim 27, wherein the first primary power value is equal to, greater than, or lower than the second primary power value.

29. A method comprising:

receiving a digital pulsing signal, the digital pulsing signal having two states;

switching from applying a first frequency input to a primary RF power supply when the digital pulsing signal is in a first one of the two states to applying a second frequency input to the primary RF power supply when the digital pulsing signal is in a second one of the two states;

determining a third frequency input to apply to a secondary RF power supply when the digital pulsing signal is in the first state.

30. The method of claim 29, wherein the method is used to process semiconductor wafers to make integrated circuits.