Dual Control Modes for Plasma Impedance
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Solution Overview
Problem
Current plasma systems face challenges in effectively controlling plasma impedance for both high and low energy processes, as existing methods often prioritize either RF power or ion energy without accurately accounting for both voltage and current, leading to suboptimal control and efficiency in plasma etching and deposition processes.
Innovation Solution
Implementing dual control modes within a plasma system, where different variables such as RF power and ion energy are used based on specific states (S1 and S0) to adjust impedance, with processors determining the appropriate variables to control plasma impedance by measuring RF signals and ion energy, and adjusting power accordingly to ensure optimal conditions for high and low energy processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If RF power is used to control plasma impedance during high energy processes, then power delivery is improved, but ion energy control becomes inaccurate
Solution Approach 1:
The system dynamically switches between two control modes based on process state: during high energy processes (state S1), RF power is the controlled variable; during low energy processes (state S0), ion energy becomes the controlled variable. This dynamic adaptation allows the system to optimize for power delivery when needed while ensuring accurate ion energy control when required, resolving the contradiction between these two objectives.
Solution Approach 2:
The invention changes the controlled parameter based on process conditions. The controller monitors plasma conditions and switches between controlling RF power and controlling ion energy depending on whether the process is in high energy state (S1) or low energy state (S0). This parameter switching enables the system to achieve both effective power delivery and precise ion energy control at different times during the process cycle.
2Manufacturing precision
If ion energy is used to control plasma impedance during low energy processes, then etching precision is improved, but power delivery efficiency decreases
Solution Approach 1:
The system employs dynamic control mode switching where ion energy control is activated specifically during low energy process states (S0) when etching precision is critical, while RF power control is used during high energy states (S1) when productivity is prioritized. This temporal separation allows the system to achieve high etching precision when needed without permanently sacrificing power delivery efficiency.
Solution Approach 2:
The control system operates in periodic cycles, alternating between high energy mode (S1) optimized for productivity and low energy mode (S0) optimized for precision. During S0 phases, ion energy is controlled to achieve precise etching; during S1 phases, RF power is controlled to maximize power delivery efficiency. This periodic switching between modes allows the system to achieve both precision and productivity over the complete process cycle.
Data Source
AI summary
Systems and methods for using variables based on a state associated with a plasma system. A method includes determining whether the state associated with the plasma system is a first state or a second state and determining a first variable upon determining that the state is the first state. The first variable is determined based on a measurement at a communication medium. The method further includes determining a second variable upon determining that the state is the second state. The second variable is determined based on a measurement at the communication medium. The method includes determining whether the second variable exceeds a first threshold, providing an instruction to reduce power supplied to a plasma chamber upon determining that the second variable exceeds the first threshold, and providing an instruction to increase power supplied to the plasma chamber upon determining that the second variable is below the first threshold.