Apparatus and methods for improving the stability of RF power delivery to a plasma load
AssigneeLam Research Corporation
InventorsArthur M. Howald, Andras Kuthi, Andrew D. Bailey, III
Life of this patent
Estimating the term…
Abstract
Methods for improving the stability of RF power delivery to a plasma load are disclosed. The method includes adding an RF resistor and/or a power attenuator at one of many specific locations in the RF power system to lower the impedance derivatives while keeping the matching circuit substantially in tune with the RF transmission line.
Claims20
A method of manufacturing a given radio frequency (RF) generator configured for use to at least generate a plasma in a plasma processing system, the method comprising:
- receiving a plurality of data points, said plurality of data points representing a first set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- for a set of stable plasmas of interest and a given RF cable length associated with said plasma processing system, a term PG in said first set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- representing output power of a first RF generator, a term
- ∂
- Z
- T
- ∂
- P
- G
- in said first set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- representing derivative of a load impedance with respect to said output power of said first RF generator;
- obtaining a second set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- ,
- said second set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- representing values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- in a stable operating region of said given RF generator, a term PG in said second set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- representing output power of said given RF generator, a term
- ∂
- Z
- T
- ∂
- P
- G
- in said second set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- representing derivative of a load impedance with respect to said output power of said given RF generator;
- changing design parameters for said given RF generator to cause said second set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- to substantially encompass said first set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- ;
- and
- designing and manufacturing said given RF generator using said design parameters.
A method of obtaining stable plasma when using a given RF generator to process a substrate in a plasma processing chamber of a plasma processing system, the method comprising:
- generating a plurality of data points using a first RF generator different from said given RF generator, said plurality of data points representing a first set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- for a set of stable plasmas of interest and a first RF cable length associated with said first RF generator in said plasma processing system, a term PG in said first set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- representing output power of said first RF generator, a term
- ∂
- Z
- T
- ∂
- P
- G
- in said first set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- representing derivative of a load impedance with respect to said output power of said first RF generator;
- obtaining a second set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- ,
- said second set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- representing values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- in a stable operating region of said given RF generator, a term PG in said second set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- representing output power of said given RF generator, a term
- ∂
- Z
- T
- ∂
- P
- G
- in said second set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- representing derivative of a load impedance with respect to said output power of said given RF generator;
- and
- conducting, employing a RF transmission line of a second RF cable length, RF signals from said given RF generator when said given RF generator is employed with said plasma processing system, said second RF cable length being selected such that said second set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- substantially encompasses said first set of values of
- P
- G
-
- ∂
- Z
- T
- ∂
- P
- G
- .
Dependencies are inferred from the claim text.