Modular Pulsed Voltage Source for Fast Plasma Pulse Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Producing high voltage pulses with fast rise and fall times is challenging, especially in circuits with high capacitance loads, and existing technologies struggle to achieve steep slopes efficiently in a compact manner with variable pulse widths, voltages, and repetition rates.
Innovation Solution
A high voltage switch comprising multiple switch modules with transformers and isolated power supplies, allowing for the generation of high voltage pulses with rise times less than 100 ns and frequencies greater than 10 kHz, using a series configuration of switch modules with transformer cores and secondary windings to minimize stray capacitance and inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If standard electrical components are used to produce high voltage pulses, then the circuit design is simpler, but the rise time and fall time become excessively long and the slope becomes insufficient
Solution Approach 1:
The high voltage pulse generation circuit is divided into multiple modular switch modules (first switch module, second switch module, etc.), each containing a switch, transformer, and trigger. This segmentation allows each module to be optimized independently for fast switching while maintaining overall system functionality, achieving rise times less than 100 ns without excessive complexity.
Solution Approach 2:
The patent employs dynamic switching control where switches are turned on and off in specific sequences to generate high voltage pulses with steep slopes. The dynamic operation of switches S1-S4 in combination with transformers T1-T4 enables rapid voltage transitions (greater than 10^11 V/s) by controlling the timing and duration of switch closure, achieving fast rise and fall times adaptively.
2Speed
If the pulse slope is increased to achieve fast rise time, then the rise time improves, but the difficulty of producing such steep slopes increases dramatically
Solution Approach 1:
Transformers are introduced as intermediary components between the low voltage control circuitry and the high voltage output. The transformers step up the voltage while the switch modules control the timing, mediating between the easy-to-control low voltage side and the high voltage output side. This allows steep slopes (greater than 10^11 V/s) to be achieved without directly manipulating high voltage switches, making the system easier to manufacture and control.
Solution Approach 2:
The patent changes multiple parameters simultaneously: voltage (stepping up from control voltage to high voltage), time (achieving rise times less than 100 ns), and frequency (operating at greater than 10 kHz). By coordinating these parameter changes through the switch modules and transformers, the system achieves steep pulse slopes that would be difficult to produce with fixed parameter designs.
3Adaptability or versatility
If high voltage pulses with variable pulse widths, voltages, and repetition rates are produced, then the adaptability improves, but the device complexity increases
Solution Approach 1:
The switch modules are designed with universal functionality to handle multiple operating conditions. Each module can operate independently or in combination with others, allowing the same hardware configuration to produce variable pulse widths, voltages, and repetition rates. The controllers can adjust the timing and sequencing of switch modules to achieve different pulse parameters without requiring additional hardware, maintaining simplicity while providing versatility.
4Quantity of substance
If circuits with high capacitance loads are used, then the energy storage capacity increases, but the ability to achieve fast rise time and fall time deteriorates
Solution Approach 1:
The patent employs periodic switching action where switches are turned on and off in rapid succession to charge and discharge capacitive loads. By using multiple switch modules operating in sequence with periods less than 100 ns, the system can deliver high current pulses to charged capacitive loads while maintaining fast rise and fall times. The periodic recharging of capacitors through the switch modules allows sustained high-speed operation even with high capacitance loads.
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
The solution enables the production of high voltage pulses with steep rise and fall times, efficiently handling capacitive loads and achieving uniform electric fields across wafers, thereby improving wafer yield and reducing defects.
Implementation Method 1
a first transformer electrically coupled with a control voltage power source and electrically coupled with the first switch, providing a voltage less than the first voltage rating
Data Source
AI summary
Embodiments provided herein generally include apparatus, e.g., plasma processing systems, and methods for the plasma processing of a substrate in a processing chamber. Some embodiments are directed to a waveform generator. The waveform generator generally includes a first voltage stage having: a first voltage source; a first switch; a ground reference; a transformer having a first transformer ratio, the first transformer comprising: a primary winding coupled to the first voltage source and the ground reference; and a secondary winding having a first end and a second end, wherein the first end is coupled to the ground reference, and the second end is configured to be coupled to a load through a common node; and a first diode coupled in parallel with the primary winding of the first transformer. The waveform generator generally also includes one or more additional voltage stages coupled to a load through the common node.