Simplified voltage-boosting snubber network
AssigneeAdvanced Energy Industries, Inc.
InventorsFaleh Alskran, John Dorrenbacher
Life of this patent
Estimating the term…
Abstract
This disclosure describes a non-dissipative snubber circuit configured to boost a voltage applied to a load after the load's impedance rises rapidly. The voltage boost can thereby cause more rapid current ramping after a decrease in power delivery to the load which results from the load impedance rise. In particular, the snubber can comprise a combination of a capacitive element, two inductive elements, and three switches, where a duty cycle of two of the three switches controls the voltage boost. The snubber can be arranged between a DC power supply and a switching circuit configured to generate a pulsed waveform for provision to the load.
Claims19
A snubber for a pulsed DC power supply system, the snubber comprising:
- an input coupled to a DC power supply;
- an output coupled to a switching circuit, the switching circuit configured to provide pulsed DC power to a load;
- a low-level connection of the DC power supply;
- a first inductive element coupled between a first node and a second node;
- a second inductive element coupled between the first node and a third node, the third node coupled to the output;
- a capacitive element coupled between the first node and a fourth node;
- a first switch coupled between the third and fourth nodes;
- a second switch coupled between the second and fourth nodes;
- and
- a third switch coupled between the second node and the low-level connection of the DC power supply.
A pulsed DC power supply system configured to provide pulsed DC to electrodes in a plasma processing chamber, the pulsed DC power supply system comprising:
- a DC power supply configured to provide a process voltage, V1, to a first and a second rail;
- a first switching circuit coupled to the first and second rails, and configured to convert the process voltage, V1, and any other voltage on the first and second rails, to a pulsed output for provision to the electrodes in the plasma processing chamber;
- a voltage-boosting circuit coupled between the first and second rails and comprising:
- a capacitive element;
- two inductive elements;
- and
- three switches, wherein
- the two inductive elements and the capacitive element are connected at a first node, and wherein
- the voltage-boosting circuit is configured to draw current from the DC power supply when an impedance of the plasma processing chamber increases thereby raising a voltage between the first and second rail by a boost voltage, V2, where the boost voltage, V2, is selectable by a duty cycle of two of the three switches.
A method of providing pulsed power to a plasma processing chamber, the method comprising:
- providing a snubber circuit coupled to a switching circuit, the snubber circuit configured to be coupled between a DC power supply and the switching circuit, and the switching circuit configured to be coupled between the snubber circuit and the plasma processing chamber, the snubber circuit comprising two switches whose duty cycle is configured to control a voltage across a capacitor of the snubber circuit and thereby to regulate a DC voltage provided at an output of the switching circuit to the plasma processing chamber;
- accessing from memory, for the switching circuit, a target boost voltage, target pulsed output duty cycle, target pulsed output frequency, and target output current;
- setting a duty cycle of the two switches to achieve the target boost voltage at the output of the switching circuit;
- and
- delivering a first pulsed DC voltage to an electrode in the plasma processing chamber.
Dependencies are inferred from the claim text.