Modular Pulse Generator for High-Voltage Capacitive Plasma Loads
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Plasma treatment applications, such as etching or layer deposition, require high voltage and high frequency rectangular, asymmetrical, pulsed voltage supplies, which often exceed the voltage handling capabilities of individual semiconductor switches, especially during high frequency operation.
Innovation Solution
A high power generator configured with multiple low power generators, each with an energy storage component, connected through a coupling and controlled by a unit to generate high voltage and current pulses, utilizing a balancing circuit and sequential activation of generators to produce step-function pulses without continuous slope, allowing efficient power delivery to capacitive loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage and high frequency pulsed voltage supply is used for plasma treatment applications, then the plasma process requirements are met, but the voltage handling capabilities of individual semiconductor switches are exceeded
Solution Approach 1:
The high power generator is divided into multiple low power generators, each with its own energy storage component. Each low power generator operates within the voltage handling capability of individual semiconductor switches, while their combined output through the coupling achieves the required high voltage and high power pulse delivery to the plasma process.
2Reliability
If multiple low power generators are combined to achieve high power output, then switch protection is improved, but device complexity increases
Solution Approach 1:
Multiple low power generators are electrically connected through a coupling to combine their outputs. This merging approach allows each generator to operate reliably within its voltage limits while achieving the required high power output when all generators are activated, thus protecting switches without excessive complexity.
Solution Approach 2:
The control unit dynamically selects which low power generators are activated based on the required output power level. This dynamic activation allows the system to scale from low to high power operation, using only the necessary number of generators, thereby reducing complexity during low power operation while maintaining protection during high power operation.
3Productivity
If sequential activation of low power generators is used to generate sharp voltage transitions, then power delivery efficiency is improved, but control complexity increases
Solution Approach 1:
Energy storage components in each low power generator are charged to predefined values in advance. During pulse delivery, the control unit sequentially activates pre-charged generators, allowing rapid voltage transitions without requiring complex real-time charging control, thus improving power delivery efficiency while keeping control complexity manageable.
4Power
If high voltage pulses are delivered to capacitive loads, then plasma process requirements are met, but power losses increase
Solution Approach 1:
The system uses pulsed operation with periodic charging and discharging of energy storage components. By charging capacitors to predefined values and then rapidly discharging them in sequence, the system delivers high voltage pulses to capacitive loads while minimizing continuous power dissipation, thus reducing overall power losses during switching operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the generation of high power pulses with varying amplitudes, efficiently handling capacitive loads in plasma processes by protecting switches from overvoltage and overcurrent, reducing power losses, and providing sharp voltage transitions, thus improving the reliability and efficiency of plasma processing systems.
Implementation Method 1
Each respective low power (LP) generator (14, 16, 18) comprises an energy storage component (C1, C2, Cn), wherein in use the energy storage component is charged to a respective predefined value related to the energy storage component
Implementation Method 2
The balancing circuit (58) comprises a component allowing a current to flow in one direction only, in particular a diode (58a) or component working like a diode
Data Source
AI summary
A high power (HP) generator includes a plurality of low power (LP) generators, a coupling in which the plurality of LP generators is electrically connected, and a control unit. During operation, a coupling-value at an output of the coupling is higher than an LP-generator-value at an output of one of the plurality of LP generators. The control unit is configured to select a contribution of each LP generator in order to generate a rise and/or a decay of a pulse at the output of the coupling. The HP generator further includes a balancing circuit connected between two LP generators. The balancing circuit includes a component allowing a current to flow in one direction only.