Plasma Chamber Bias Electrode Layout for Radial Density Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing plasma processing apparatuses face challenges in adjusting the distribution of plasma density in the chamber, which affects the efficiency of plasma processing.
Innovation Solution
The apparatus includes a chamber with a substrate support, a radio-frequency power supply, and a bias power supply system. The bias power supply system provides electrical bias energy to first and second electrodes, adjusting the electric field strength above these electrodes to control plasma density distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single electrode structure is used in plasma processing, then the device complexity is reduced, but the ability to adjust plasma density distribution is insufficient
Solution Approach 1:
The electrode structure is divided into multiple independent electrodes (first electrode, second electrode, third electrode) with different functions. The first electrode generates plasma, the second electrode controls sheath height above the substrate, and the third electrode controls sheath height above the edge ring. This segmentation enables independent control of plasma density distribution without requiring a completely complex device architecture.
Solution Approach 2:
Different regions of the chamber are provided with different electrode structures tailored to local requirements. The central region has the first electrode for plasma generation, the substrate area has the second electrode for sheath control, and the edge ring area has the third electrode for localized sheath adjustment. This local differentiation optimizes plasma density distribution while maintaining reasonable device complexity.
2Manufacturing precision
If DC voltage is applied to the edge ring to adjust sheath position, then the sheath height above the edge ring is controlled, but the overall plasma density distribution remains difficult to optimize
Solution Approach 1:
The sheath control function is segmented from the edge ring and assigned to a separate third electrode. This allows the third electrode to control the sheath above the edge ring independently, while the second electrode controls the sheath above the substrate. This segmentation enables precise sheath positioning and simultaneous optimization of overall plasma density distribution.
Solution Approach 2:
The third electrode acts as an intermediary element between the edge ring and the plasma generation system. By introducing this intermediate control point, the system can adjust the sheath height above the edge ring without directly modifying the edge ring structure, providing versatile control over plasma density distribution.
3Power
If RF power is provided to the lower electrode for plasma generation, then plasma is generated effectively, but the plasma density distribution becomes difficult to control uniformly
Solution Approach 1:
The plasma generation function is segmented from the lower electrode and assigned to a dedicated first electrode. This first electrode is specifically designed for efficient plasma generation through RF power coupling, while the lower electrode can focus on providing a stable base potential. This functional segmentation enables both high plasma generation efficiency and controllable density distribution.
Solution Approach 2:
Different electrodes are optimized for different local functions: the first electrode for plasma generation efficiency, the second electrode for substrate-area sheath control, and the third electrode for edge ring-area sheath control. This local optimization ensures uniform plasma density distribution while maintaining high generation efficiency in each region.
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 configuration allows for the adjustment of plasma density distribution in the radial direction within the chamber, enhancing the uniformity and efficiency of plasma processing.
Implementation Method 1
The radio-frequency power supply generates source radio-frequency power to generate plasma from a gas in the chamber
Implementation Method 2
The bias power supply system provides first electrical bias energy to a first electrode and second electrical bias energy to a second electrode... to increase electric field strength above one of the central portion or the outer portion
Implementation Method 3
This causes the gas in the chamber to generate plasma. The substrate is processed with a chemical species such as ions or radicals in the plasma
Data Source
AI summary
A plasma processing apparatus includes a chamber, a substrate support, a radio-frequency power supply, and a bias power supply system. The substrate support is in the chamber and includes a central portion on which a substrate is placeable. The radio-frequency power supply generates source radio-frequency power. The bias power supply system respectively provides first electrical bias energy and second electrical bias energy to a first electrode and a second electrode. The first electrode is at least in the central portion of the substrate support. The second electrode is in an outer portion located outward from the central portion in a radial direction that is radial from a center of the central portion. The bias power supply system adjusts the first and second electrical bias energy to increase electric field strength above one of the central portion or the outer portion earlier than electric field strength above the other portion.