Plasma RF Power Phasing to Suppress Reflected Waves
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Solution Overview
Problem
Existing plasma processing apparatuses face issues with the reflection of radio-frequency power used for plasma generation, which can lead to inefficiencies and potential damage to equipment.
Innovation Solution
The apparatus includes a substrate support with an electrode, a radio-frequency power supply, and a bias power supply, where the radio-frequency power supply adjusts its output power level in multiple phase periods to ensure that the evaluation value of reflected waves is less than or equal to a predetermined allowable value, thereby suppressing reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If radio-frequency power is supplied to generate plasma in the chamber, then plasma generation efficiency is improved, but radio-frequency power reflection increases causing equipment damage risk
Solution Approach 1:
The patent applies dynamics by making the radio-frequency power level adjustable in real-time according to the processing stage. The power supply transitions from a high power level during plasma generation to a low power level during ion drawing, allowing the system to adapt its characteristics to different operational requirements and prevent power reflection damage
Solution Approach 2:
The patent implements periodic action by alternating between two distinct power levels in a cyclic manner. The radio-frequency power is supplied at a first power level during plasma generation phases and then switched to a second power level during ion drawing phases, creating a periodic power delivery pattern that optimizes both plasma generation and prevents reflection
2Quantity of substance
If high radio-frequency power is used for plasma generation, then plasma density is improved, but reflected wave power level increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the radio-frequency power level parameter based on the plasma processing stage. The system switches between a first power level (higher) for plasma generation and a second power level (lower) for ion drawing, optimizing plasma density while controlling reflected wave power through parameter modulation
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 effectively reduces the reflection of radio-frequency power, protecting the equipment and maintaining efficient plasma generation by adjusting power levels and frequencies to meet specific criteria.
Implementation Method 1
The radio-frequency power supply is configured to supply radio-frequency power to generate plasma in the chamber
Implementation Method 2
The bias power supply is configured to supply electric bias energy to the electrode to draw ions into a substrate placed on the substrate support
Data Source
AI summary
A plasma processing apparatus disclosed herein includes a substrate support provided in a chamber; a radio-frequency power supply configured to supply radio-frequency power to generate plasma in the chamber; and a bias power supply configured to supply electric bias energy to an electrode to draw ions into a substrate on the substrate support. The electric bias energy has a cycle having a time length reciprocal to a bias frequency. The radio-frequency power supply is further configured to adjust an output power level of the radio-frequency power in a plurality of phase periods in the cycle such that an evaluation value is less than or equal to a first value, the evaluation value being a power level of reflected waves of the radio-frequency power or a value of a ratio of the power level to the output power level.