Plasma RF Pulse Synchronization for Deep Hole Etching Control
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Solution Overview
Problem
Current plasma processing technologies face challenges in efficiently controlling ion energy and plasma parameters, particularly in deep hole etching with high aspect ratios, due to limitations in radio-frequency power supply configurations and synchronization.
Innovation Solution
A plasma processing apparatus with a configuration that includes a source RF generator, two bias RF generators, and matching circuits to supply synchronized pulsed signals of three radio-frequency power levels to the antenna and substrate support, allowing for precise control of plasma generation and ion energy through non-overlapping power states and frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple RF power supplies with different frequencies are used to control plasma parameters, then plasma generation and ion energy control are improved, but device complexity increases
Solution Approach 1:
The system divides the RF power control into three separate RF power supplies, each operating at different frequencies (e.g., 13 MHz, 27 MHz, 40 MHz). Each RF power supply independently controls specific plasma parameters, allowing precise control of plasma generation and ion energy without requiring complex modulation of a single power supply
Solution Approach 2:
The patent employs pulsed RF power supply modes where each RF power supply operates in synchronized pulses with different duty cycles. This periodic action allows dynamic control of plasma density and ion energy by adjusting pulse width and frequency, achieving precise etching control while maintaining manageable device complexity
2Productivity
If RF power levels are increased to improve etching speed, then productivity increases, but by-product adhesion worsens
Solution Approach 1:
The system uses pulsed RF power supply with optimized duty cycles to maintain high etching speed during active pulses while allowing cleaning phases during off-periods. This periodic operation prevents by-product accumulation on masks and substrates that would occur with continuous high-power operation
Solution Approach 2:
Different RF power supplies with different frequencies are assigned to control different aspects of the plasma: one frequency controls plasma density (affecting etching speed), while another frequency controls ion energy (affecting by-product removal). This local quality control allows simultaneous optimization of productivity and prevention of by-product adhesion
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 configuration enhances the efficiency and accuracy of substrate processing by controlling ion incidence angles and mask selectivity, improving etching performance and preventing by-product adhesion.
Implementation Method 1
a source RF generator configured to generate a source RF pulsed signal... a first bias RF generator configured to generate a first bias RF pulsed signal... a second bias RF generator configured to generate a second bias RF pulsed signal
Implementation Method 2
allowing for precise control of plasma generation and ion energy through non-overlapping power states and frequencies
Data Source
AI summary
A plasma processing apparatus includes: a source RF generator that generates a source RF pulsed signal of at least three power levels; first and second bias RF generators that generate first and second bias RF pulsed signals of at least two power levels; a synchronization signal generator that generates a synchronization signal; a first matching circuit connected to the source RF generator and an antenna, thereby allowing the source RF pulsed signal to be supplied from the source RF generator to the antenna through the first matching circuit; and a second matching circuit connected to the first and second bias RF generators and a substrate support, thereby allowing the first and second bias RF pulse signals to be supplied from the first and second bias RF generators to the substrate support through the second matching circuit.