Clamped Monolithic Showerhead Electrode for Plasma Processing
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Solution Overview
Problem
Existing showerhead electrodes in plasma processing systems face challenges in reliable temperature control and uniform gas distribution, making it difficult to achieve consistent plasma chemistry and efficient processing.
Innovation Solution
A clamped monolithic showerhead electrode design with a central and peripheral portion, featuring a specific pattern of gas outlets and a stepped outer surface for improved temperature control and gas distribution, is introduced. The electrode is securely attached to a backing plate using cam locks, ensuring efficient thermal management and uniform gas dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional showerhead electrode design is used, then the structure is simpler, but temperature control reliability deteriorates
Solution Approach 1:
The showerhead electrode is divided into multiple independent segments that can be separately cooled through individual coolant channels. This segmentation allows each region to be temperature-controlled independently, improving overall temperature control reliability while maintaining manageable structural complexity through modular design.
Solution Approach 2:
Different regions of the showerhead electrode are provided with different cooling characteristics through varied coolant channel configurations and thickness variations. This local quality approach ensures that each area of the electrode maintains optimal temperature for its specific function, enhancing temperature control reliability without requiring complete redesign of the entire structure.
2Manufacturing precision
If a conventional gas outlet pattern is used, then the electrode structure is simpler, but gas distribution uniformity deteriorates
Solution Approach 1:
The gas outlet pattern is designed with varying outlet densities and sizes in different regions of the showerhead electrode. Areas requiring higher gas distribution are provided with more or larger outlets, while other areas have fewer or smaller outlets. This local quality approach achieves uniform gas distribution across the chamber without requiring an overly complex overall pattern design.
Solution Approach 2:
The gas outlet configuration transitions from a simple two-dimensional pattern to a three-dimensional arrangement by varying outlet depth, angle, and layering within the electrode structure. This dimensional approach enables sophisticated gas distribution control while maintaining a relatively simple external electrode geometry.
3Reliability
If temperature control is enhanced with complex cooling systems, then temperature control reliability improves, but device complexity increases
Solution Approach 1:
The cooling system is merged with the electrode structure itself, integrating coolant channels directly into the electrode body rather than using separate external cooling apparatus. This integration achieves reliable temperature control while reducing overall device complexity by eliminating independent cooling components and simplifying the system architecture.
Solution Approach 2:
The electrode structure serves multiple functions simultaneously: it provides the electrical field for plasma generation, distributes process gas through integrated outlets, and controls temperature through built-in coolant channels. This multi-functionality approach achieves reliable temperature control without adding separate dedicated cooling systems, thereby reducing device complexity.
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
The design enhances temperature control and gas distribution, leading to improved plasma chemistry and processing efficiency, facilitating the production of well-defined vertically etched sidewalls and consistent semiconductor fabrication.
Implementation Method 1
a plurality of circumferentially spaced apart sockets are located in the upper face in the peripheral portion, the sockets configured to received cam locks therein adapted to clamp the showerhead electrode to a backing plate
Implementation Method 2
A plurality of gas outlets are located in the central portion of the showerhead electrode through which process gas can be delivered to a gap between the showerhead electrode and a lower electrode
Implementation Method 3
The electric field established between the anode and the cathode will dissociate the reactive gas forming plasma
Implementation Method 4
The electric field created by the electrodes will attract the ions to the cathode, causing the ions to strike the surface in a predominantly vertical direction
Implementation Method 5
The upper electrode is a showerhead electrode provided with gas outlet(s), which permit the gas to be uniformly dispersed through the electrode into the chamber
Data Source
AI summary
An electrode assembly for a plasma reaction chamber used in semiconductor substrate processing. The assembly includes an upper showerhead electrode which is mechanically attached to a backing plate by a series of spaced apart cam locks. A guard ring surrounds the backing plate and is movable to positions at which openings in the guard ring align with openings in the backing plate so that the cam locks can be rotated with a tool to release locking pins extending from the upper face of the showerhead electrode.