System for high power RF plasma processing
First Claim
1. A method of plasma processing comprising the steps of:
- a) supplying a dc input having a potential;
b) dividing said potential among a plurality of amplifiers each having a radio frequency output;
c) supplying a radio frequency drive signal to each of said amplifiers;
d) superimposing a variable dc level upon said radio frequency drive signal to form a combined signal;
e) supplying said combined signal to said amplifiers;
f) varying said dc level;
g) combining said radio frequency outputs of said amplifiers to create at least one high power, radio frequency output;
h) creating a plasma through action of said high power, radio frequency output; and
i) processing using said plasma.
1 Assignment
0 Petitions
Accused Products
Abstract
A high power radio frequency power method of amplifications described in which a variety of amplifiers (60 & 86) may be used to reduce the stress any one amplifier experiences. The power leads (64 & 65) may be arranged in a series to power each amplifier at potentials which are lower than the total potential. Outputs (63) may then be connected in a parallel fashion to combine the power output by the system. A variety of unique stabilization, drive, division, combination, and supply configurations are presented as well as the possibility of utilization and adaptation of the designs for a plasma processing system. An aspect of tiered combining is included such as may be especially appropriate for larger numbers of devices which may include switchmode amplifiers and the like.
67 Citations
40 Claims
-
1. A method of plasma processing comprising the steps of:
-
a) supplying a dc input having a potential;
b) dividing said potential among a plurality of amplifiers each having a radio frequency output;
c) supplying a radio frequency drive signal to each of said amplifiers;
d) superimposing a variable dc level upon said radio frequency drive signal to form a combined signal;
e) supplying said combined signal to said amplifiers;
f) varying said dc level;
g) combining said radio frequency outputs of said amplifiers to create at least one high power, radio frequency output;
h) creating a plasma through action of said high power, radio frequency output; and
i) processing using said plasma. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
a) partitioning said amplifiers into pairs wherein said radio frequency output of each of said amplifiers has a substantially in-phase component;
b) combining said substantially in-phase components of said radio frequency outputs from each of said amplifiers of said pairs to form a first set of summed outputs each having substantially in-phase output components;
c) partitioning said first set of summed outputs into at least one pair;
d) combining said substantially in-phase output components of said first set of summed outputs to form at least one second summed output .
-
-
12. A method of plasma processing as described in claim 11 and further comprising the steps of repeating said steps 11 c) and 11 d) wherein said second summed output is considered as a first set of summed outputs, and wherein said steps 11 c) and 11 d) are repeated to achieve said high power, radio frequency output.
-
13. A method of plasma processing as described in claim 12 wherein said step of repeating continues until a last pair of common electrical points are connected into a final common electrical point.
-
14. A method of plasma processing as described in claim 11 wherein said step of combining comprises passing said radio frequency outputs through at least one pair of mutually coupled inductors.
-
15. A method of plasma processing as described in claim 1 wherein said radio frequency drive signal has a constant amplitude.
-
16. A method of plasma processing as described in claim 1 or 15 wherein said amplifiers have a threshold voltage and wherein said radio frequency drive signal is large compared to said threshold voltage of said amplifiers.
-
17. A method of plasma processing as described in claim 1 wherein said step of supplying a radio frequency drive signal to each of said amplifiers comprises the steps of:
-
a) supplying an input signal at a fundamental frequency to a radio frequency amplifier;
b) supplying a power supply voltage to said radio frequency amplifier through a power supply feed line;
c) providing resonant isolation of said power supply feed line at said fundamental frequency;
d) placing an element in series with said power supply feed line providing high impedance at high frequencies; and
e) affirmatively absorbing energy from said element at other than said fundamental frequency.
-
-
18. A method of plasma processing comprising the steps of:
-
a) supplying a dc input having a potential to at least one radio frequency amplifier;
b) supplying a radio frequency drive signal to said amplifier;
d) superimposing a variable dc level upon said radio frequency drive signal to form a combined signal;
e) supplying said combined signal to said amplifiers;
f) varying said dc level;
g) operating said amplifier comprising the steps of;
i) providing a generator having output semiconductor devices to deliver a rated output power into a nominal design load at a particular die temperature for said devices; and
ii) operating said devices at power levels which permit continual cooling substantially beyond that required to maintain said die temperature at said rated output power into said design load; and
h) creating a high power, radio frequency output which is responsive to said amplifier;
i) creating a plasma through action of said high power, radio frequency output; and
j) processing using said plasma.
-
-
19. A method of plasma processing comprising the steps of:
-
a) supplying a dc input having a potential to at least one radio frequency amplifier;
b) supplying a radio frequency drive signal to said amplifier;
d) superimposing a variable dc level upon said radio frequency drive signal to form a combined signal;
e) supplying said combined signal to said amplifiers;
f) varying said dc level;
g) operating said amplifier comprising the steps of;
i) providing a generator having output semiconductor devices to deliver a rated output power into a nominal design load at a particular die temperature for said devices; and
ii) providing an increased output capacitance from said devices; and
h) creating a high power, radio frequency output which is responsive to said amplifier;
i) creating a plasma through action of said high power, radio frequency output; and
j) processing using said plasma.
-
-
20. A method of plasma processing comprising the steps of:
-
a) supplying a dc input having a potential to at least one radio frequency amplifier;
b) supplying a radio frequency drive signal to said amplifier;
d) superimposing a variable dc level upon said radio frequency drive signal to form a combined signal;
e) supplying said combined signal to said amplifiers;
f) varying said dc level;
g) operating said amplifier comprising the steps of;
i) providing a generator having output semiconductor devices to deliver a rated output power into a nominal design load; and
ii) blocking reflected power from being transmitted back to said devices; and
h) creating a high power, radio frequency output which is responsive to said amplifier;
i) creating a plasma through action of said high power, radio frequency output; and
j) processing using said plasma.
-
-
21. A method of plasma processing comprising the steps of:
-
a) supplying a dc input having a potential to at least one radio frequency amplifier;
b) supplying a radio frequency drive signal to said amplifier;
d) superimposing a variable dc level upon said radio frequency drive signal to form a combined signal;
e) supplying said combined signal to said amplifiers;
f) varying said dc level;
g) operating said amplifier comprising the steps of;
i) providing a generator having output semiconductor devices to deliver a rated output power into a nominal design load; and
ii) limiting the continuous operation of said devices to power levels which are 80 percent of said rated output power of said devices; and
h) creating a high power, radio frequency output which is responsive to said amplifier;
i) creating a plasma through action of said high power, radio frequency output; and
j) processing using said plasma.
-
-
22. A plasma processing system comprising:
-
a) a source of power having a dc potential;
b) at least one driver supplying a radio frequency drive signal;
c) a variable dc level circuit;
d) combining circuitry responsive to said radio frequency drive signal and said variable dc level circuit and which forms a combined signal;
e) a plurality of power amplifiers responsive to said radio frequency drive signal, said plurality of amplifiers connected whereby across each of said amplifiers is impressed less than said potential;
f) combining circuitry responsive to at least two of said amplifiers having at least one output;
g) at least one electromagnetic coupling element, connected to said output; and
h) at least one plasma element connected to said electromagnetic coupling element. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
a) a plurality of first order connections between each pair of said amplifiers acting to combine substantially in-phase components of said radio frequency outputs from said amplifiers so as to produce an output having a phase; and
b) at least one second order connection responsive to and acting to combine substantially in-phase components of said output from at least two of said first order connections.
-
-
34. A plasma processing system as described in claim 22 wherein said radio frequency drive signal has a constant amplitude.
-
35. A plasma processing system as described in claim 22 or 34 wherein said power amplifiers have a threshold voltage and wherein said radio frequency drive signal is large compared to said threshold voltage of said power amplifiers.
-
36. A plasma processing system as described in claim 22 and further comprising:
-
a. a power supply supplying a voltage to a power supply feed line of said power amplifiers;
b. a resonant isolation circuit providing isolation of said power supply feed line at said fundamental frequency;
c. a series element in series with said power supply feed line providing high impedance at high frequencies; and
d. at least one loss component which affirmatively absorbs energy from said element at other than said fundamental frequency.
-
-
37. A plasma processing system comprising:
-
a) a source of power having a dc potential;
b) at least one driver supplying a radio frequency drive signal;
c) a variable dc level circuit;
d) combining circuitry responsive to said radio frequency drive signal and said variable dc level circuit and which forms a combined signal;
e) at least one power amplifiers responsive to said radio frequency drive signal comprising;
i) a generator having output semiconductor devices to deliver a rated output power into a nominal design load at a particular die temperature for said devices; and
ii) an increased cooling capability for said devices which permits continual cooling substantially beyond that required to maintain said die temperature at said rated output power into said design load; and
f) at least one plasma element responsive to said amplifier.
-
-
38. A plasma processing system comprising:
-
a) a source of power having a dc potential;
b) at least one driver supplying a radio frequency drive signal;
c) a variable dc level circuit;
d) combining circuitry responsive to said radio frequency drive signal and said variable dc level circuit and which forms a combined signal;
e) at least one power amplifiers responsive to said radio frequency drive signal comprising;
i) a generator having output semiconductor devices to deliver a rated output power into a nominal design load at a particular die temperature for said devices; and
ii) an increased output capacitance added across the output of said devices beyond that otherwise required to be designed into said generator; and
f) at least one plasma element responsive to said amplifier.
-
-
39. A plasma processing system comprising:
-
a) a source of power having a dc potential;
b) at least one driver supplying a radio frequency drive signal;
c) a variable dc level circuit;
d) combining circuitry responsive to said radio frequency drive signal and said variable dc level circuit and which forms a combined signal;
e) at least one power amplifiers responsive to said radio frequency drive signal comprising;
i) a generator having output semiconductor devices to deliver a rated output power into a nominal design load at a particular die temperature for said devices; and
ii) a blocking element which blocks any reflected power from being transmitted back to said devices; and
f) at least one plasma element responsive to said amplifier.
-
-
40. A plasma processing system comprising:
-
a) a source of power having a dc potential;
b) at least one driver supplying a radio frequency drive signal;
c) a variable dc level circuit;
d) combining circuitry responsive to said radio frequency drive signal and said variable dc level circuit and which forms a combined signal;
e) at least one power amplifiers responsive to said radio frequency drive signal comprising;
i) a generator having output semiconductor devices to deliver a rated output power into a nominal design load at a particular die temperature for said devices; and
ii) a power limiter which limits the continuous operation of said devices to power levels which are 80 percent of said rated output power of said devices; and
f) at least one plasma element responsive to said amplifier.
-
Specification