Pulsed RF Plasma Generator With Series Amplifier Voltage Steps
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Solution Overview
Problem
Current RF generator systems face challenges in precisely controlling power signals for plasma etching in semiconductor fabrication, particularly in achieving high aspect ratio features and efficient power delivery to plasma chambers, which affects etch rate and feature profile control.
Innovation Solution
A power generator system with multiple power amplifiers and a control module that synchronizes their operation to produce varying DC voltages, including a fixed step generation section and a variable step generation section, to generate a piecewise linear output voltage, and a DC/DC converter to optimize power delivery to the plasma chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple power amplifiers are used to increase output power and control precision, then power delivery efficiency and etch rate control improve, but device complexity and space requirements increase
Solution Approach 1:
The power amplifier is divided into multiple independent amplifiers (first power amplifier and second power amplifier) connected in series. Each amplifier can be independently controlled to output different DC voltages, allowing precise control of the composite voltage waveform applied to the plasma chamber. This segmentation enables better power delivery efficiency and etch rate control while managing complexity through modular design
Solution Approach 2:
The system dynamically switches between different power amplifier configurations and control modes. The control module can selectively activate different amplifiers based on process requirements, and the amplifiers can operate in different modes (e.g., fixed step generation vs. variable step generation) to adapt to varying plasma conditions, maintaining optimal power delivery efficiency across different operating points
2Adaptability or versatility
If multiple power amplifiers with different supply voltages are used to expand voltage range, then voltage output flexibility improves, but device complexity and space requirements increase
Solution Approach 1:
Multiple power amplifiers with different supply voltages are merged into a single series-connected configuration. The first power amplifier receives a first supply voltage and the second power amplifier receives a second supply voltage, and their series connection produces a composite voltage output that combines both contributions. This merging approach expands voltage output flexibility while consolidating space requirements compared to having separate output systems
Solution Approach 2:
Each power amplifier is designed with multi-functionality to handle different supply voltage levels and output modes. The amplifiers can operate in fixed step generation mode or variable step generation mode, and can be controlled to output different voltage levels based on process requirements. This universality allows a single amplifier design to serve multiple voltage range requirements, reducing the need for additional specialized components
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 system enables precise control of ion energy distribution and efficient power delivery, improving etch rate and feature profile control, reducing intermodulation distortion, and minimizing space requirements in the fabrication environment.
Implementation Method 1
a first power amplifier configured to receive a first supply voltage and to output a plurality of DC voltages, and a second power amplifier configured to receive the first supply voltage and to output the plurality of DC voltages
Implementation Method 2
The first power amplifier and the second power amplifier are connected in series, and the power generator generates an output voltage that varies in accordance with a one of the plurality of DC voltages output by the first power amplifier and a one of the plurality of DC voltages output by the second power amplifier
Implementation Method 3
In plasma processing, ions are accelerated by an electric field to etch material from or deposit material onto a surface of a substrate. In one basic implementation, the electric field is generated based on Radio Frequency (RF) or Direct Current (DC) power signals generated by a respective RF or DC generator
Implementation Method 4
In plasma processing, ions are accelerated by an electric field to etch material from or deposit material onto a surface of a substrate
Data Source
AI summary
A power generator has a first plurality of power amplifiers each configured to receive a first, common supply voltage and to output a plurality of discrete DC voltages. At least one of the plurality of discrete DC voltages may be varied by varying the first, common supply voltage. The RF power generator may also include a second plurality of power amplifiers receiving a second either common or distinct supply voltage that differs from the first supply voltage. At least one of the plurality of discrete DC voltages may be varied by varying the second common or distinct supply voltage. The output of each power amplifier is added in series to generate an output voltage for the power generator. One of the plurality of power amplifiers is actuated or deactuated at a first time and an other of the plurality of power amplifiers is actuated or deactuated at a second time.