Nonsinusoidal RF Signal Filtering for Ion Energy Control
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Solution Overview
Problem
In plasma-based systems, controlling ion energy within a plasma chamber to prevent undesirable etching on wafers is challenging due to the limitations of existing techniques, which often result in inaccurate ion energy distribution and potential damage to thin layers.
Innovation Solution
A system is implemented that includes a sinusoidal RF generator, a nonsinusoidal RF generator, a power amplifier, and a filter to generate and amplify RF signals, ensuring that ion energy is confined between specific thresholds, thereby achieving precise ion energy intensity and controlled etching by supplying filtered signals to the chuck and surface antenna.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional RF signal generation methods are used, then plasma is generated for etching, but ion energy cannot be precisely controlled resulting in undesirable etching in wrong areas
Solution Approach 1:
The patent applies dynamics by transitioning from static sinusoidal RF signals to dynamic nonsinusoidal RF signals with adjustable duty cycles. The RF signal waveform is dynamically modified to control ion energy distribution, allowing precise control of ion bombardment characteristics during etching while maintaining ease of operation through programmable signal generation
Solution Approach 2:
The patent changes the parameter of RF signal waveform from sinusoidal to nonsinusoidal with variable duty cycles (e.g., 10% to 90%). This parameter change directly controls the temporal distribution of ion energy, enabling precise control of etching processes while avoiding undesirable etching in incorrect areas
2Reliability
If ion energy is not precisely controlled, then etching can be performed, but ion energy distribution becomes inaccurate causing damage to thin layers
Solution Approach 1:
The patent employs periodic nonsinusoidal RF signals with controlled duty cycles to create periodic bursts of ion energy. This periodic action allows precise control of when and how ions bombard the substrate, protecting thin layers from damage while maintaining accurate ion energy distribution for reliable etching processes
Solution Approach 2:
The dynamic modulation of RF signal duty cycle enables real-time control of ion energy delivery. By adjusting the duty cycle parameter, the system dynamically adapts ion energy distribution to protect thin layers while maintaining etching precision, thereby improving both reliability and manufacturing precision simultaneously
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 allows for precise control of ion energy between defined thresholds, reducing the risk of undesirable etching and enhancing the precision of processes like wafer etching and material deposition by maintaining ion energy within a controlled range.
Implementation Method 1
one or more radio frequency (RF) generators generate RF signals. The RF signals are provided to a plasma chamber to generate plasma within the plasma chamber
Implementation Method 2
a nonsinusoidal RF generator for generating a nonsinusoidal signal. The system further includes a power amplifier coupled to the nonsinusoidal RF generator. The power amplifier is used for amplifying the nonsinusoidal signal to generate an amplified signal. The system includes a filter coupled to the power amplifier. The filter is used for filtering the amplified signal using a filtering signal to generate a filtered signal
Implementation Method 3
The RF signals are provided to a plasma chamber to generate plasma within the plasma chamber. The plasma is used for a variety of purposes, e.g., to etch a wafer, to clean a wafer, to deposit materials on a wafer, etc.
Data Source
AI summary
Systems and methods controlling ion energy within a plasma chamber are described. One of the systems includes an upper electrode coupled to a sinusoidal RF generator for receiving a sinusoidal signal and a nonsinusoidal RF generator for generating a nonsinusoidal signal. The system further includes a power amplifier coupled to the nonsinusoidal RF generator. The power amplifier is used for amplifying the nonsinusoidal signal to generate an amplified signal. The system includes a filter coupled to the power amplifier. The filter is used for filtering the amplified signal using a filtering signal to generate a filtered signal. The system includes a chuck coupled to the filter. The chuck faces at least a portion of the upper electrode and includes a lower electrode. The lower electrode is used for receiving the filtered signal to facilitate achieving ion energy at the chuck to be between a lower threshold and an upper threshold.