Arc recovery without over-voltage for plasma chamber power supplies using a shunt switch
First Claim
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1. A method for applying power to a plasma chamber, comprising:
- delivering power from a power supply unit to the plasma chamber to ignite and sustain a plasma;
detecting an arc in the plasma;
diverting a plasma current associated with the arc away from the plasma by closing at a first time for a first time period a shunt switch within the power supply unit so as to extinguish the arc, the shunt switch being opened at a second time at the end of the first time period when there is no arc in the plasma and a plasma voltage is at an extinguished level;
increasing the plasma voltage to reignite the plasma when the shunt switch is open; and
pulsing the shunt switch with a plurality of pulses as the plasma voltage increases after the shunt switch is opened at the second time, the shunt switch being closed during each pulse to limit increases in the plasma voltage so that the plasma voltage does not exceed a voltage limit, and the shunt switch being open during an off-time between pulses to increase the plasma voltage to a reignition level that ignites the plasma, the shunt switch remains open after the plasma is ignited until another arc is detected to sustain the plasma.
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Abstract
A system and method for over-voltage protection is described. In one embodiment of the invention, an apparatus includes an output port configured to deliver power to a plasma chamber to ignite a plasma. The apparatus also includes a shunt switch in parallel with the output port and a processor configured to receive an indicator of an arc in the plasma. The processor is configured to close the shunt switch for a period of time to divert current away from the arc. The processor is also configured to trigger a pulse of the shunt switch to limit a voltage of an increasing voltage condition associated with the arc.
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Citations
11 Claims
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1. A method for applying power to a plasma chamber, comprising:
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delivering power from a power supply unit to the plasma chamber to ignite and sustain a plasma; detecting an arc in the plasma; diverting a plasma current associated with the arc away from the plasma by closing at a first time for a first time period a shunt switch within the power supply unit so as to extinguish the arc, the shunt switch being opened at a second time at the end of the first time period when there is no arc in the plasma and a plasma voltage is at an extinguished level; increasing the plasma voltage to reignite the plasma when the shunt switch is open; and pulsing the shunt switch with a plurality of pulses as the plasma voltage increases after the shunt switch is opened at the second time, the shunt switch being closed during each pulse to limit increases in the plasma voltage so that the plasma voltage does not exceed a voltage limit, and the shunt switch being open during an off-time between pulses to increase the plasma voltage to a reignition level that ignites the plasma, the shunt switch remains open after the plasma is ignited until another arc is detected to sustain the plasma. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus, comprising:
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an output port that delivers power to a plasma chamber to ignite a plasma; a shunt switch in parallel with the output port, the shunt switch is open while the output port delivers power to the plasma chamber; a processor to control the shunt switch; a non-transitory, tangible storage medium, encoded with instructions readable by the processor to extinguish an arc in the plasma and recover after the arc is extinguished, the instructions including instructions to; detect an arc in the plasma; divert a plasma current associated with the arc away from the plasma by closing at a first time for a first time period a shunt switch within the power supply unit to extinguish the arc, the shunt switch being opened at a second time at the end of the first time period when there is no arc in the plasma and a plasma voltage is at an extinguished level; increase the plasma voltage to reignite the plasma when the shunt switch is open; and pulse the shunt switch with a plurality of pulses as the plasma voltage increases after the shunt switch is opened at the second time, the shunt switch being closed during each pulse to limit increases in the plasma voltage so that the plasma voltage does not exceed a voltage limit, and the shunt switch being open during an off-time between pulses to increase the plasma voltage to a reignition level that ignites the plasma, the shunt switch remains open after the plasma is ignited until another arc is detected to sustain the plasma. - View Dependent Claims (8, 9, 10, 11)
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Specification