Plasma Bias Pulse Sequencing for Variable Ion Energy Control
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Solution Overview
Problem
Existing plasma processing technologies face challenges in efficiently varying the energy of ions supplied to substrates during processing, limiting the precision and effectiveness of plasma processing methods.
Innovation Solution
A plasma processing apparatus with a power source system that applies distinct bias voltages in different periods, outputting first and second pulses with varying voltage levels to the substrate electrode, allowing for the supply of ions with different energies at different times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single bias voltage is applied to the electrode during plasma processing, then the processing conditions are simple and stable, but the ion energy supplied to the substrate cannot be varied, limiting processing precision and effectiveness
Solution Approach 1:
The power source system applies bias voltage in periodic pulse patterns with different duty cycles. By varying the duty cycle (ratio of pulse on-time to total period), the average ion energy supplied to the substrate can be precisely controlled without changing the peak voltage level. This periodic modulation allows dynamic adjustment of ion energy while maintaining system simplicity.
Solution Approach 2:
The invention changes the temporal parameters of the bias voltage (pulse width, duty cycle, frequency) rather than the voltage amplitude itself. This allows the effective ion energy to be varied by modifying the time-domain characteristics of the applied voltage, achieving processing precision improvement without requiring multiple voltage sources or complex amplitude modulation circuits.
2Adaptability or versatility
If the bias voltage is continuously varied to change ion energy, then processing flexibility is improved, but the system complexity and control difficulty increase
Solution Approach 1:
Instead of continuously varying the bias voltage amplitude, the system uses periodic pulses with variable duty cycles. This discrete temporal modulation provides processing flexibility through different duty cycle ratios while avoiding the complexity of continuous amplitude control circuits. The periodic nature simplifies the power source design compared to continuous variation methods.
Solution Approach 2:
The system introduces temporal dynamics through pulse width modulation. By dynamically adjusting the pulse duration within each period, the average ion energy can be adapted to different processing requirements. This dynamic control is achieved through simple timing circuits rather than complex continuous voltage regulation, maintaining system simplicity while improving versatility.
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
Enables the precise control of ion energy supplied to the substrate, enhancing the precision and effectiveness of plasma processing by allowing for the use of ions with varying energies in different periods, which can improve etching processes and film handling.
Implementation Method 1
configured to apply a bias voltage to the electrode to draw ions from a plasma in the chamber into the substrate on the substrate support
Data Source
AI summary
The disclosed plasma processing apparatus is provided with a chamber, a substrate support, and a power source system. The substrate support has an electrode and configured to support a substrate in the chamber. The power source system is electrically connected to the electrode and configured to apply a bias voltage to the electrode to draw ions from a plasma in the chamber into the substrate on the substrate support. The power source system is configured to output a first pulse to the electrode in a first period and output a second pulse to the electrode in a second period after the first period, as the bias voltage. Each of the first pulse and the second pulse is a pulse of a voltage. A voltage level of the first pulse is different from a voltage level of the second pulse.