Multi-zone Upper Electrode Radial Plasma Control
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Solution Overview
Problem
Plasma processing in typical plasma chambers is not uniform across the center to edge of a substrate, leading to inconsistent etch rates and processing outcomes.
Innovation Solution
A plasma processing system with a multi-zone upper electrode featuring concentric gas injection zones, temperature control layers, and RF power sources, allowing for independent adjustment of gas feeds, temperatures, and RF power to manipulate plasma processing conditions radially across the substrate, including the use of tuning gases to adjust the carbon/fluorine ratio and etch rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single showerhead type upper electrode with evenly distributed outlet ports is used, then the structure is simple and easy to manufacture, but the plasma processing is not uniform across the center to edge of the substrate
Solution Approach 1:
The upper electrode is divided into multiple concentric gas injection zones (first zone, second zone, third zone) with independent gas feed control. Each zone has its own gas distribution system allowing separate adjustment of gas flow rates and compositions, enabling radial manipulation of plasma processing conditions from center to edge of the substrate.
Solution Approach 2:
Each concentric gas injection zone is equipped with independent temperature control elements and gas feeds, allowing different temperatures and gas compositions to be applied to different radial regions. This enables localized optimization of plasma processing parameters (etch rate, ion density) for center versus edge regions of the substrate.
2Manufacturing precision
If multiple concentric gas injection zones with independent control are implemented, then plasma processing uniformity and control precision are improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The electrode structure employs nested concentric zones where the first, second, and third gas injection zones are arranged concentrically one within another. Each zone contains its own gas distribution manifold and temperature control elements, creating a nested configuration that integrates multiple control functions within a unified electrode assembly.
Solution Approach 2:
The upper electrode serves multiple functions simultaneously: it acts as an RF electrode for plasma generation, a gas distribution system with multiple independent zones for radial gas flow control, and a temperature control system with distributed heating/cooling elements. This multi-functionality consolidates what could be separate systems into a single integrated component.
3Stability of the object's composition
If gas feeds are aligned across concentric zones, then the gas distribution symmetry is improved, but the ability to create radial plasma gradients is reduced
Solution Approach 1:
The gas feed configurations are made dynamically adjustable rather than fixed. Each concentric zone's gas feeds can be independently positioned (aligned or offset) and their flow rates independently controlled. This dynamic capability allows the system to switch between symmetric gas distribution (aligned feeds) and asymmetric distributions (offset feeds) depending on the desired plasma profile.
Solution Approach 2:
The patent explicitly contemplates offsetting gas feeds in outer zones relative to inner zones to create asymmetric gas distribution patterns. This asymmetry enables radial plasma gradients where different regions of the substrate experience different gas compositions and flow rates, allowing control over etch rate variations from center to edge.
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 precise control over etch rates and plasma processing uniformity from the center to the edge of the substrate, improving processing consistency and efficiency by varying gas distributions and temperatures across concentric zones.
Implementation Method 1
The gas distribution layer 110 includes multiple gas passages 112, 114 to distribute the process gases evenly to the ports 106 across the surface layer 104
Implementation Method 2
The temperature control layer 120 includes elements 122. Elements 122 can heat or cool the temperature control layer 120, as desired, to control the temperature of the upper electrode 102
Implementation Method 3
a plasma chamber and a controller coupled to the plasma chamber. The plasma chamber including a substrate support and an upper electrode opposite the substrate support
Data Source
AI summary
A system and method of plasma processing includes a plasma processing system including a plasma chamber and a controller coupled to the plasma chamber. The plasma chamber including a substrate support and an upper electrode opposite the substrate support, the upper electrode having a plurality of concentric gas injection zones.