Plasma Showerhead Assembly With Conductive Inserts for Defect Reduction
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Solution Overview
Problem
Existing showerhead assemblies in microwave plasma processing chambers experience plasma light-up in gas openings, leading to particle and defect generation, particularly in high plasma density deposition processes like PEALD, which degrade o-rings and reduce microwave source reliability.
Innovation Solution
Incorporation of conductive inserts within or adjacent to the dielectric faceplate gas openings in the plasma showerhead assembly, protected by a dielectric coating, to shield o-rings from plasma light-up and reduce defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional showerhead assemblies are used in microwave plasma processing, then gas flow through openings is achieved, but plasma light-up in gas openings occurs leading to particle and defect generation
Solution Approach 1:
A conductive insert is introduced as an intermediary element within the gas openings of the dielectric faceplate. This insert acts as a mediator that prevents plasma from directly interacting with the gas flow path, thereby eliminating plasma light-up and the associated particle and defect generation while maintaining proper gas flow through the openings
Solution Approach 2:
The conductive insert is placed specifically within the gas openings where plasma light-up occurs, providing localized protection against plasma discharge. This local modification addresses the harmful plasma light-up phenomenon at the specific location of gas openings without affecting the overall showerhead assembly structure or gas distribution pattern
2Productivity
If existing showerhead assemblies are used in high plasma density processes, then deposition is achieved, but o-ring degradation occurs due to plasma light-up
Solution Approach 1:
The conductive insert serves as a protective intermediary between the plasma environment and the o-ring sealing elements. By preventing plasma light-up in the gas openings, the insert indirectly protects the o-rings from plasma exposure and degradation, maintaining their integrity and sealing performance during high plasma density deposition processes
Solution Approach 2:
The conductive insert provides beforehand protection by preventing plasma light-up before it can occur in the gas openings. This proactive measure shields the o-rings from plasma exposure before degradation can happen, ensuring o-ring integrity is maintained throughout the deposition process
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
Reduces plasma light-up in gas openings, protecting o-rings and enhancing microwave source reliability by minimizing defects and extending the plasma source's lifespan.
Implementation Method 1
attenuating the plasma with one or more conductive inserts in the dielectric faceplate gas openings
Implementation Method 2
a plurality of o-rings surrounding the conductive plate gas openings and the dielectric faceplate gas openings and configured to seal the dielectric faceplate gas openings and the conductive plate gas openings from atmospheric pressure
Implementation Method 3
a microwave plasma power supply configured to generate a microwave plasma that is delivered through the plasma showerhead assembly
Data Source
AI summary
Plasma showerhead assemblies are disclosed comprising a conductive plate having a plurality of the conductive plate gas openings, a dielectric faceplate having a thickness and a plurality of dielectric faceplate gas openings extending through the dielectric faceplate thickness in fluid communication with the plurality of the conductive plate gas openings. A plurality of tri-lobed o-rings surrounding the conductive plate gas openings and the dielectric faceplate gas openings are configured to form a seal between the dielectric faceplate gas openings and the conductive plate gas openings from atmospheric pressure.