Pulsed RF Plasma Processing for High-Aspect-Ratio Etch Control
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Solution Overview
Problem
Existing plasma processing technologies face challenges in achieving precise control over ion energy, ion incident angle, radical flux, ion flux, and by-products during high aspect ratio plasma etching, leading to shape abnormalities and inefficient processing.
Innovation Solution
A plasma processing apparatus that employs pulsed RF power with source and bias RF signals having multiple power levels, where the transition timing of the bias RF signal is shifted relative to the source RF signal, allowing for independent control of plasma parameters and improved etching performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous RF power is supplied to achieve high etching rate, then productivity is improved, but control precision over plasma parameters deteriorates
Solution Approach 1:
The patent applies periodic pulsing of source RF power and bias RF power to achieve precise control over plasma parameters while maintaining high etching rates. By alternating between ON and OFF states in a controlled manner, the system can independently regulate ion energy, ion incident angle, radical flux, and ion flux, thereby resolving the contradiction between productivity and manufacturing precision.
2Device complexity
If simple single-level RF pulsing is used to reduce device complexity, then device complexity is reduced, but control precision over plasma parameters deteriorates
Solution Approach 1:
The patent segments the RF power supply into distinct source RF power and bias RF power components, each with independent pulse control. This segmentation allows separate regulation of plasma generation and ion acceleration, enabling precise control over multiple plasma parameters simultaneously without excessive device complexity.
Solution Approach 2:
The patent implements dynamic control by allowing independent adjustment of pulse width, duty cycle, and power levels for both source RF and bias RF signals. This dynamic capability enables real-time optimization of plasma parameters to achieve high precision control while maintaining manageable device complexity through flexible signal modulation.
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 apparatus achieves improved control over plasma parameters, reducing shape abnormalities and enhancing the processing performance of plasma etching, particularly for high aspect ratio features.
Implementation Method 1
a source RF generator configured to generate a source RF signal. The source RF signal includes source cycles, and each of the source cycles includes a source ON state and a source OFF state
Implementation Method 2
a bias RF generator configured to supply a bias RF signal to a lower electrode. The bias RF signal includes bias cycles corresponding to the source cycles, respectively
Implementation Method 3
The apparatus achieves improved control over plasma parameters, reducing shape abnormalities and enhancing the processing performance of plasma etching
Data Source
AI summary
A plasma processing apparatus includes a plasma processing chamber, a substrate support, a source RF generator, and a bias RF generator. The substrate support is disposed within the plasma processing chamber. The source RF generator is configured to generate a source RF signal. The source RF signal includes source cycles, and each of the source cycles includes a source ON state and a source OFF state. The source ON state has at least two source power levels. The bias RF generator is coupled to the substrate support and configured to generate a bias RF signal. The bias RF signal includes bias cycles corresponding to the source cycles, respectively. Each of the bias cycles includes a bias ON state and a bias OFF state. The bias ON state has at least two bias power levels.