Etch rate modeling and use thereof with multiple parameters for in-chamber and chamber-to-chamber matching

• US 9,502,221 B2
• Filed: 04/02/2014
• Issued: 11/22/2016
• Est. Priority Date: 07/26/2013
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Valcore, John C. Jr., Singh, Harmeet, Povolny, Henry
• Primary Examiner(s): Vu, Jimmy
• Application Number:
  US14/243,705
• Publication Number:
  US 20150032245A1
• Time in Patent Office: 965 Days
• Field of Search: 315/111.01, 315/111.21, 315/111.41, 315/111.51, 315/111.71, 156/345.21, 156/345.28, 156/345.48
• US Class Current: 1/1
• CPC Class Codes: G05B 19/418 Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS] or computer integrated manufacturing [CIM]
• CPC Class Codes: H01J 37/32183 Matching circuits
• CPC Class Codes: H01J 37/32926 Software, data control or modelling
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H01J 37/3299 Feedback systems

Abstract

A method includes receiving a voltage and current measured at an output of an RF generator of a first plasma system and calculating a first model etch rate based on the voltage and current, and a power. The method further includes receiving a voltage and current measured at an output of the RF generator of a second plasma system, determining a second model etch rate based on the voltage and current at the output of the RF generator of the second plasma system, and comparing the second model etch rate with the first model etch rate. The method includes adjusting a power at the output of the RF generator of the second plasma system to achieve the first model etch rate associated with the first plasma system upon determining that the second model etch rate does not match the first model etch rate. The method is executed by a processor.

Claims

1. A method for performing chamber-to-chamber matching of etch rates based on a model etch rate, the method comprising:

receiving a voltage and current measured at an output of a radio frequency (RF) generator of a first plasma system;

calculating a first model etch rate based on the voltage and current, and a power, the power calculated based on the voltage and current and a phase between the voltage and current;

receiving a voltage and current measured at an output of an RF generator of a second plasma system;

determining a second model etch rate based on the voltage and current at the output of the RF generator of the second plasma system;

comparing the second model etch rate with the first model etch rate; and

adjusting a power at the output of the RF generator of the second plasma system to achieve the first model etch rate associated with the first plasma system upon determining that the second model etch rate does not match the first model etch rate,

wherein the method is executed by a processor.

2. The method of claim 1, further comprising adjusting the voltage or current at the output of the RF generator of the second plasma system to achieve the first model etch rate associated with the first plasma system.

3. The method of claim 1, wherein the voltage and current used to calculate the first model etch rate includes a voltage magnitude and a current magnitude, and the phase between the voltage magnitude and the current magnitude, and the power used to calculate the first model etch rate includes a power magnitude, the power magnitude calculated as a product of the voltage magnitude, the current magnitude, and the phase.

4. The method of claim 1, further comprising:

receiving a frequency measured at the output of the RF generator of the first plasma system;

calculating a third model etch rate based on the frequency;

receiving a frequency measured at the output of the RF generator of the second plasma system;

determining a fourth model etch rate based on the frequency measured at the output of the RF generator of the second plasma system;

comparing the third model etch rate with the fourth model etch rate; and

adjusting the power at the output of the RF generator of the second plasma system to achieve the third model etch rate associated with the first plasma system.

5. The method of claim 4, further comprising adjusting the frequency at the output of the RF generator of the second plasma system to achieve the third model etch rate associated with the first plasma system.

6. The method of claim 4, wherein receiving the voltage and current and the frequency measured at the output of the RF generator of the first plasma system is performed using a dummy wafer in a plasma chamber of the first plasma system.

7. The method of claim 1, wherein the RF generator of the first plasma system is coupled to an impedance matching circuit via a cable, and wherein the impedance matching circuit is coupled to a plasma chamber via an RF transmission line.

8. The method of claim 1, wherein the output of the RF generator of the first plasma system is coupled to an input of an impedance matching circuit, wherein the output is used to facilitate transfer of an RF signal to a plasma chamber via the impedance matching circuit.

9. The method of claim 1, wherein adjusting the power at the output of the RF generator of the second plasma system is performed when the second plasma system is used to etch a semiconductor wafer.

10. The method of claim 1, wherein adjusting the power includes increasing or decreasing the power measured at the output of the RF generator of the second plasma system.

11. The method of claim 1, wherein the first plasma system includes a tool that is identical in function to a tool of the second plasma system and has a different identification than that of the second plasma system.

12. The method of claim 1, wherein the first plasma system includes a tool that is identical in structure to a tool of the second plasma system and has a different identification than that of the second plasma system.

13. The method of claim 1, wherein the first plasma system includes a tool that is identical in structure and function to a tool of the second plasma system and has a different identification than that of the second plasma system.

14. The method of claim 1, wherein calculating the first model etch rate including calculating a sum, wherein the sum is a Taylor series.

15. A method for performing in-chamber matching of etch rates based on a model etch rate, the method comprising:

receiving a voltage and current measured at a first time at an output of a radio frequency (RF) generator of a plasma system;

calculating a first model etch rate based on the voltage, the current, and a power, the power calculated based on a phase between the voltage and the current;

receiving a voltage and a current measured at a second time at the output of the RF generator;

calculating a second model etch rate based on the voltage measured at the second time, the current measured at the second time, and a power, the power calculated based on a phase between the voltage measured at the second time and the current measured at the second time;

comparing the first model etch rate with the second model etch rate; and

adjusting power at the output of the RF generator to achieve the first model etch rate upon determining that the second model etch rate does not match the first model etch rate,

wherein the method is executed by a processor.

16. The method of claim 15, further comprising:

receiving a frequency measured at the first time at the output of the RF generator;

calculating a third model etch rate based on the frequency;

receiving a frequency measured at the second time at the output of the RF generator;

calculating a fourth model etch rate based on the frequency measured at the second time;

comparing the third model etch rate with the fourth model etch rate; and

adjusting the power at the output of the RF generator to achieve the third model etch rate upon determining that the third model etch rate does not match the fourth model etch rate.

17. The method of claim 16, further comprising:

adjusting the voltage or current or frequency at the output of the RF generator to achieve the third model etch rate.

18. The method of claim 16, wherein receiving the voltage, the current, and the frequency measured at the first time at the output of the RF generator is performed using a dummy wafer in a plasma chamber of the plasma system.

19. The method of claim 15, wherein the second time occurs after the first time.

20. The method of claim 15, wherein the voltage and current used to calculate the first model etch rate includes a voltage magnitude, a current magnitude, and the phase between the voltage magnitude and the current magnitude, and the power used to calculate the first model etch rate includes a power magnitude.

21. The method of claim 15, wherein adjusting the power at the output of the RF generator is performed when the plasma system is used to etch a semiconductor wafer.

22. A first plasma system comprising:

a radio frequency (RF) generator for generating an RF signal, the RF generator including an output for facilitating transfer of the RF signal;

a complex impedance sensor coupled to the output for measuring a voltage and current of the RF signal;

a plasma chamber for generating plasma;

an impedance matching circuit coupled to the RF generator via a cable and coupled to the plasma chamber via an RF transmission line for modifying the RF signal to generate a modified RF signal;

wherein the plasma chamber is configured to generate the plasma when the modified RF signal is received from the impedance matching circuit;

a processor coupled to the complex impedance sensor for;

receiving the voltage and current measured at the output of the RF generator;

calculating a first model etch rate based on the voltage and current, and a power, the power calculated based on the voltage and current and a phase between the voltage and current;

receiving a voltage and current measured at an output of an RF generator of a second plasma system;

determining a second model etch rate based on the voltage and current at the output of the RF generator of the second plasma system;

comparing the second model etch rate with the first model etch rate; and

adjusting a power at the output of the RF generator of the first plasma system to achieve the first model etch rate upon determining that the second model etch rate does not match the first model etch rate.

23. The first plasma system of claim 22, wherein the processor is further configured to adjust the voltage or the current at the output of the RF generator of the first plasma system to achieve the first model etch rate.