Plasma Bias Waveform Generator Using Resonant Current Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current plasma assisted processing technologies face challenges in accurately controlling the bias voltage and ion energy distribution due to limited efficiency and flexibility in existing amplifiers, leading to undesired ion energy distribution and reproducibility issues, as well as increased reactor sizes and resonance problems that result in slow switching speeds and additional losses.
Innovation Solution
A voltage waveform generator with a common node and current source, featuring a voltage waveform generation circuit and a current source with adjustable voltage levels, which minimizes ripple and allows for precise control of the voltage waveform, reducing oscillations and enabling faster convergence to the ideal waveform, while sharing a power source with the voltage waveform generation circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If switch mode power supply is used to generate periodic voltage function, then ion energy distribution can be controlled, but voltage oscillations and ringing occur due to resonance in the LC circuit
Solution Approach 1:
The patent converts the harmful resonance effect into a beneficial fast switching mechanism. By deliberately exciting the LC circuit resonance through controlled switching of the semiconductor device, the system achieves rapid voltage transitions (high dV/dt) that would otherwise be limited. The resonance is not suppressed but rather harnessed to enable faster commutation and improved waveform control, directly addressing the contradiction between waveform precision and stability.
2Stability of the object's composition
If damping resistance is added to suppress resonance, then voltage ringing is reduced, but additional energy losses occur
Solution Approach 1:
Instead of using damping resistance to suppress resonance (which causes energy loss), the patent converts the resonance into a useful fast switching mechanism. The controlled excitation of LC circuit resonance enables rapid voltage transitions without requiring energy-dissipating damping elements, thus achieving waveform stability without the penalty of additional energy losses.
Solution Approach 2:
The patent replaces the passive mechanical damping approach (using resistance to dissipate energy) with an active electronic control mechanism. By using controlled semiconductor switching to harness resonance, the system achieves waveform stabilization through active control rather than passive energy dissipation, eliminating the need for damping resistance and its associated losses.
3Stability of the object's composition
If slow switching speeds are used to suppress resonance excitation, then voltage ringing is reduced, but discharge time increases and process efficiency decreases
Solution Approach 1:
The patent converts the previously harmful resonance excitation into a beneficial fast switching mechanism. By deliberately controlling the semiconductor device to excite LC circuit resonance, the system achieves rapid voltage transitions (high dV/dt) that improve both waveform control and process efficiency simultaneously, eliminating the need to trade off switching speed for stability.
4Manufacturing precision
If wideband linear amplifiers are used for bias voltage generation, then process control accuracy is improved, but system efficiency is limited
Solution Approach 1:
The patent employs periodic switching action of semiconductor devices to generate the bias voltage waveform. By using pulsed periodic switching instead of continuous linear amplification, the system achieves both high waveform control accuracy (through precise timing and resonant control) and high efficiency (by minimizing continuous power dissipation). The periodic nature of the switching allows for accurate waveform generation while dramatically reducing energy losses compared to wideband linear amplifiers.
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
This solution provides improved control over the voltage waveform, reducing oscillations and enabling more precise approach to the ideal waveform, resulting in enhanced process control and reduced footprint, thereby addressing the limitations of existing technologies.
Implementation Method 1
a voltage waveform generation circuit (11) operably connected to the common node (13) and configured to apply a voltage signal at the common node (13)
Implementation Method 2
a current source (16) operably connected to the common node (13) and configured to apply a DC current at the common node (13), in particular, the DC current is a negative current
Implementation Method 3
a switch mode power supply for forming a periodic voltage function at an exposed surface of the substrate to be processed
Implementation Method 4
The inherent plasma reactor capacitance and the stray inductance of the interconnection between reactor and bias voltage generator form an LC circuit having an inherent resonance characteristic
Data Source
Figure 1~2
Figure 3
Figure 4A~4C
AI summary
Voltage waveform generator for plasma assisted processing apparatuses A voltage waveform generator comprises a common node, a voltage waveform generation circuit and a current source. The voltage waveform generation circuit is operably connected to the common node and is configured to apply a voltage signal at the common node. The current source is operably connected to the common node and configured to apply a DC current at the common node. The current source comprises a first switch node connected to the common node through a first inductor, and a first power supply connected to the first switch node. The power supply comprises at least two first voltage nodes, and the current source is operable to switch between the at least two first voltage nodes at the first switch node.