Plasma Electrode Control for Narrow Ion Energy Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for controlling the ion energy distribution function (IEDF) during plasma processing are inefficient, relying on iteration loops that are slow and often result in non-convergence, leading to inaccurate plasma parameter estimation and broadened IEDF.
Innovation Solution
The implementation of a method that uses a single loop to determine ion current and compensation current, employing a substrate support with embedded electrodes and edge ring voltage control circuits, coupled with a power module that actively controls the IEDF width through tunable voltage sources, allowing for precise adjustment of the IEDF.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If periodic alternating voltage is applied to electrode(s) of a chamber, then plasma sheath develops above the substrate and ions are accelerated, but ion current charges the substrate and alters the substrate potential, which broadens the IEDF
Solution Approach 1:
The patent implements a feedback control system where the IEDF width is measured and used to adjust the DC voltage component of the electrode voltage. The controller modifies the DC voltage based on the measured IEDF width to maintain the desired narrow width, creating a closed-loop control that compensates for the broadening effect caused by ion current charging.
Solution Approach 2:
The patent changes the parameters of the electrode voltage by separating it into AC and DC components. By independently controlling the DC voltage component while maintaining the AC component for plasma generation, the system can adjust the substrate potential to compensate for ion current effects and maintain narrow IEDF width.
2Manufacturing precision
If state-of-the-art iteration loops are used to control the IEDF, then control is achieved, but the process is inefficient and results in non-convergence
Solution Approach 1:
The patent implements a feedback control system where the IEDF width is measured and used to adjust the DC voltage component of the electrode voltage. The controller modifies the DC voltage based on the measured IEDF width to maintain the desired narrow width, creating a closed-loop control that compensates for the broadening effect caused by ion current charging.
Solution Approach 2:
The patent changes the parameters of the electrode voltage by separating it into AC and DC components. By independently controlling the DC voltage component while maintaining the AC component for plasma generation, the system can adjust the substrate potential to compensate for ion current effects and maintain narrow IEDF width.
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 enables faster achievement of a desired IEDF width, such as a narrow IEDF, by eliminating iteration loops and providing accurate plasma parameter determination, resulting in improved control over ion energy distribution during plasma processing.
Implementation Method 1
The ions flowing towards the substrate are accelerated by the plasma sheath voltage which correlates with the voltage applied to the electrode
Implementation Method 2
when periodic alternating voltage is applied to electrode(s) of a chamber, a plasma sheath can develop above the substrate
Implementation Method 3
ion current can charge the substrate and alter the substrate potential, which in turn affects the plasma sheath voltage
Data Source
AI summary
Embodiments of the present disclosure generally relate to apparatus and methods for controlling an ion energy distribution during plasma processing. In an embodiment, the apparatus includes a substrate support that has a body having a substrate electrode for applying a substrate voltage to a substrate, and an edge ring electrode embedded for applying an edge ring voltage to an edge ring. The apparatus further includes a substrate voltage control circuit coupled to the substrate electrode, and an edge ring voltage control circuit coupled to the edge ring electrode. The substrate electrode, edge ring electrode, or both are coupled to a power module configured to actively control an energy distribution function width of ions reaching the substrate, edge ring, or both. Methods for controlling an energy distribution function width of ions during substrate processing are also described.