Protecting high-frequency amplifers
First Claim
1. A method of protecting high-frequency amplifiers of a plasma supply device configured to deliver a high-frequency output signal having a power of more than 500 W and a substantially constant fundamental frequency greater than 3 MHz to a plasma load, the method comprising:
- driving two high frequency amplifiers with two drive signals having a common frequency and a predetermined phase shift with respect to one another;
generating two high frequency source signals using the two high frequency amplifiers, the two high frequency source signals being coupled in a coupler to form a combined high frequency output signal;
transmitting the combined high frequency output signal to the plasma load;
measuring electrical variables related to load impedances seen by the two high frequency amplifiers;
determining load impedances seen by the two high frequency amplifiers; and
in response to determining that the load impedance seen by one of the two high frequency amplifiers lies outside a predetermined range, adjusting the phase shift of the two drive signals sufficiently to cause a phase shift of the high frequency source signals with respect to one another, the phase shift of the high frequency source signals causing the load impedances seen by the two high frequency amplifiers to lie within the predetermined range.
1 Assignment
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Accused Products
Abstract
In one aspect, protecting high frequency (HF) amplifiers of a plasma supply device configured to deliver >500 W at a substantially constant fundamental frequency >3 MHz is accomplished by: driving two HF amplifiers with two drive signals having a common frequency and a predetermined phase shift with respect to one another; generating two HF source signals using the HF amplifiers, the HF source signals coupled in a coupler to form a HF output signal; transmitting the HF output signal to the plasma load; measuring electrical variables related to the load impedances seen by the two HF amplifiers; determining whether the load impedance seen by one of the HF amplifiers lies outside a predetermined range; and adjusting the phase shift of the two drive signals, wherein neither of the load impedances seen by the HF amplifiers lies outside the predetermined range.
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Citations
16 Claims
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1. A method of protecting high-frequency amplifiers of a plasma supply device configured to deliver a high-frequency output signal having a power of more than 500 W and a substantially constant fundamental frequency greater than 3 MHz to a plasma load, the method comprising:
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driving two high frequency amplifiers with two drive signals having a common frequency and a predetermined phase shift with respect to one another; generating two high frequency source signals using the two high frequency amplifiers, the two high frequency source signals being coupled in a coupler to form a combined high frequency output signal; transmitting the combined high frequency output signal to the plasma load; measuring electrical variables related to load impedances seen by the two high frequency amplifiers; determining load impedances seen by the two high frequency amplifiers; and in response to determining that the load impedance seen by one of the two high frequency amplifiers lies outside a predetermined range, adjusting the phase shift of the two drive signals sufficiently to cause a phase shift of the high frequency source signals with respect to one another, the phase shift of the high frequency source signals causing the load impedances seen by the two high frequency amplifiers to lie within the predetermined range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A plasma supply device configured to generate and supply an output power of more than 500 W at a substantially constant fundamental frequency greater than 3 MHz in the form of a high-frequency output signal to a plasma load, the plasma supply device comprising:
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a first phase shifter; two high frequency amplifiers, each having at least one switching element and an output; a drive signal generator configured to drive the two high frequency amplifiers with a predetermined phase shift using the first phase shifter; a coupler having first and second ports coupled to respective outputs of the two high frequency amplifiers, and having a third port at least indirectly connected to the plasma load; a sensor coupled between the coupler and one of the two high frequency amplifiers and responsive to an electrical variable indicative of load impedances seen by the two high frequency amplifiers; and a phase adjuster configured to cooperate with the drive signal generator to adjust the phase shift of the drive signals of the high frequency amplifiers with respect to one another based on input from the sensor. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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Specification