Generator Source Impedance Control via Variable Combiner
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Solution Overview
Problem
Plasma processing systems face instability due to variations in plasma impedance, leading to undesired changes in power delivery and process variables like etch or deposition rates, which existing impedance matching and control mechanisms struggle to address effectively.
Innovation Solution
A method and system for controlling the source impedance of a generator by using a four-port combiner with a controllable variable impedance component, allowing for adjustment of the generator's source impedance to align with the plasma load's impedance trajectory, thereby stabilizing power delivery and improving process stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If impedance matching and control mechanisms are used to maintain power delivery, then power delivery stability is improved, but device complexity increases
Solution Approach 1:
The patent applies dynamics by making the source impedance adjustable rather than fixed. The system dynamically adapts the source impedance of the power generator to match the varying plasma load impedance, enabling stable power delivery without complex matching networks. This is achieved through real-time measurement of plasma impedance and adjustment of the generator's source impedance parameters.
Solution Approach 2:
The patent changes the parameter of source impedance from a fixed value to an adjustable parameter. By varying the source impedance parameters of the power generator according to the plasma load conditions, the system achieves effective impedance matching and stable power delivery while avoiding the complexity of traditional matching networks.
2Device complexity
If fixed source impedance is used in high efficiency generators, then device complexity is reduced, but adaptability to varying plasma impedance deteriorates
Solution Approach 1:
The patent transforms the static source impedance into a dynamic parameter that can be adjusted in real-time. The power generator maintains structural simplicity with fixed internal impedance but achieves adaptability through external impedance transformation networks or adjustable output stages that modify the effective source impedance to match varying plasma loads.
Solution Approach 2:
The patent introduces an intermediary impedance transformation mechanism between the fixed-impedance power generator and the variable plasma load. This intermediary component (such as a transformer or impedance matching network) adapts the fixed source impedance to various load conditions, maintaining both generator simplicity and system adaptability.
Data Source
AI summary
Systems and methods for adjusting the source impedance of a generator are disclosed. An exemplary method includes generating a first signal and applying the first signal to a first input of a combiner, generating a second signal and applying the second signal to a second input of said combiner, and combining the first and second signals with the combiner at an output of the combiner to produce power that is delivered to the plasma load. A controllable variable impedance is provided to an isolation port of the combiner, and the controllable variable impedance is adjusted to vary the source impedance of the generator.