Plasma RF Pulse Sequencing for Precise Ion Energy Control
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Solution Overview
Problem
Current plasma processing technologies face challenges in efficiently controlling ion energy and plasma processing performance due to limitations in supplying multiple radio-frequency power signals with precise timing and power levels, which affects the accuracy and efficiency of substrate processing.
Innovation Solution
A plasma processing apparatus that utilizes three RF generators to produce RF pulsed signals with specific power levels and frequencies, including a first RF pulsed signal with multiple power levels, a second RF pulsed signal with ON/OFF states, and a third RF pulsed signal with frequencies lower than the first, allowing for precise control of plasma generation and substrate processing by avoiding power signal overlaps and optimizing ion energy and incidence angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple radio-frequency power signals are supplied to control ion energy and plasma processing performance, then the accuracy and efficiency of substrate processing is improved, but the complexity of controlling timing and power levels increases
Solution Approach 1:
The patent applies periodic pulsed RF signals with different frequencies (e.g., 13 MHz and 27 MHz) and duty cycles to control plasma parameters. By using periodic on-off cycles, the system achieves precise control over ion energy and flux without requiring continuous adjustment of multiple parameters, thereby reducing control complexity while maintaining high processing accuracy
Solution Approach 2:
The patent changes key parameters including RF frequency (13 MHz vs 27 MHz), power levels (different peak and average powers), and duty cycle (pulse width ratios) to independently control different aspects of plasma processing. This allows decoupling of ion energy control from radical flux control, achieving high precision substrate processing through systematic parameter optimization
2Measurement precision
If RF pulsed signals with multiple power levels and frequencies are used, then ion energy and incidence angles are precisely controlled, but the device complexity increases
Solution Approach 1:
The patent segments the RF power supply into multiple independent RF generators operating at different frequencies (e.g., one at 13 MHz and another at 27 MHz). Each generator can be independently pulsed with specific duty cycles, allowing separate control of ion energy and radical flux. This segmentation simplifies the control architecture compared to using a single complex variable-frequency generator
Solution Approach 2:
The patent introduces pulse generation circuits as intermediary components between the RF generators and the plasma chamber. These intermediaries convert continuous RF signals into precisely timed pulsed signals with controlled duty cycles, enabling accurate control of ion energy and incidence angles without requiring direct complex modulation of the RF sources themselves
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 approach enhances the efficiency and accuracy of plasma processing by controlling ion energy and incidence angles, improving the anisotropy and selectivity of etching processes, particularly for deep holes with high aspect ratios, while minimizing by-product adherence.
Implementation Method 1
a first RF generator coupled to the first matching circuit, and configured to generate a first RF pulsed signal including a plurality of first pulse cycles
Implementation Method 2
a second RF generator coupled to the second matching circuit, and configured to generate a second RF pulsed signal including a plurality of second pulse cycles, the second RF pulsed signal having a frequency lower than a frequency of the first RF pulsed signal
Implementation Method 3
a third RF generator coupled to the second matching circuit, and configured to generate a third RF pulsed signal including a plurality of third pulse cycles, the third RF pulsed signal having a frequency lower than the frequency of the second RF pulsed signal
Implementation Method 4
The plasma processing apparatus includes: a chamber; a first matching circuit coupled to the chamber; a second matching circuit coupled to the chamber
Data Source
AI summary
A plasma processing apparatus includes: a chamber; first and second matching circuits; a first RF generator generating a first RF pulsed signal including a plurality of first pulse cycles in which each cycle includes first, second, and third periods, and the first RF pulsed signal has first, second, and third power levels in first, second, and third periods, respectively; a second RF generator generating a second RF pulsed signal including a plurality of second pulse cycles in which each cycle includes fourth and fifth periods, and the second RF pulsed signal has fourth and fifth power levels in fourth and fifth periods, respectively; and a third RF generator generating a third RF pulsed signal including a plurality of third pulse cycles in which each cycle includes sixth and seventh periods, and the third RF pulsed signal has sixth and seventh power levels in sixth and seventh periods, respectively.