Plasma Etching Bias Pulse Control for High UPEH
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in increasing Unit Per Equipment Hour (UPEH) while minimizing power consumption for bias frequency supply and optimizing the duty ratio of etching periods.
Innovation Solution
A plasma processing apparatus with a bias power supply device that applies a positive voltage pulse having a duty ratio of (1-D) to the lower electrode when the target duty ratio D exceeds a threshold, and controls non-sinusoidal power to adjust acceleration periods and rest periods for ion acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high frequency power is supplied continuously to increase ion energy and etching rate, then productivity is improved, but power consumption increases
Solution Approach 1:
The bias power supply device supplies high frequency power in periodic pulses rather than continuously. The duty ratio of the pulse is controlled to be 50% or less, meaning the power is supplied for half or less of the total cycle time. This periodic supply maintains ion acceleration during the active phase while reducing overall power consumption compared to continuous supply.
Solution Approach 2:
The invention changes the temporal distribution parameter of power supply by controlling the duty ratio of the pulse waveform. By adjusting the duty ratio to 50% or less, the system optimizes the balance between maintaining sufficient ion energy for etching and reducing the average power consumption, thereby resolving the contradiction between productivity and energy use.
2Productivity
If duty ratio of etching period is increased to optimize process cycle, then productivity is improved, but power consumption increases
Solution Approach 1:
The bias power supply device uses periodic pulse waveforms with controlled duty ratios to manage the etching process. By maintaining the duty ratio at 50% or less, the system can optimize the process cycle for higher UPEH while preventing excessive power consumption that would result from higher duty ratios.
3Productivity
If high frequency power is supplied to accelerate ions, then etching efficiency is improved, but device complexity increases
Solution Approach 1:
The bias power supply device implements periodic pulse supply with duty ratio control to simplify the power supply mechanism while maintaining effective ion acceleration. This periodic approach avoids the need for complex continuous control systems, reducing device complexity while preserving etching efficiency.
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 enhances UPEH by expanding the search range for optimal duty ratios while reducing power consumption, thus improving efficiency and optimizing the etching process.
Implementation Method 1
a high-frequency power supply device configured to supply high-frequency power to generate plasma with gas supplied to the chamber
Implementation Method 2
ions are accelerated by a potential difference between the potential of a lower electrode and the potential of plasma, and the accelerated ions are irradiated on the substrate
Implementation Method 3
a bias power supply device configured to supply pulse power configured for ion acceleration to the lower electrode
Data Source
AI summary
A plasma processing apparatus includes a chamber body including a chamber, an electrostatic chuck supporting a substrate within the chamber body and including a lower electrode, a high-frequency power supply device configured to supply high-frequency power to generate plasma with gas supplied to the chamber, and a bias power supply device configured to supply pulse power for ion acceleration to the lower electrode. The bias power supply device is configured to supply a positive voltage pulse having a duty ratio of (1-D) to the lower electrode when a target duty ratio D of an acceleration period for accelerating ions in the plasma during a process cycle exceeds a threshold.