Plasma Showerhead Conductive Inserts for Gas Opening Light-Up
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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, shielded by a dielectric coating, to mitigate plasma light-up and protect o-rings, thereby reducing defects and improving microwave source reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing showerhead assemblies are used in microwave plasma processing chambers, then gas flow through openings is achieved, but plasma light-up occurs in gas openings 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 gas delivery functionality
Solution Approach 2:
The harmful plasma light-up phenomenon is extracted or removed from the gas openings by introducing the conductive insert. The insert effectively takes out the problematic plasma interaction from the system, preventing the generation of particles and defects that would otherwise occur in the gas flow path
2Productivity
If plasma processing is performed in high plasma density deposition processes, then deposition efficiency is improved, but o-ring degradation and defect generation increase
Solution Approach 1:
The conductive insert serves as a protective intermediary that shields the o-ring from direct exposure to high plasma density and fluorine-containing species. By placing the insert at the interface where plasma would otherwise contact the o-ring, it mediates the interaction and prevents degradation while allowing the plasma processing to continue at high efficiency
3Duration of action of stationary object
If plasma light-up occurs in gas openings, then plasma processing continues, but fluorine outgassing increases reducing source lifetime
Solution Approach 1:
The conductive insert converts the harmful effect of fluorine outgassing into a beneficial outcome by providing a surface that prevents fluorine accumulation and subsequent outgassing events. The insert effectively transforms the potential harm of fluorine release into a controlled interaction that extends plasma source lifetime
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 conductive inserts effectively reduce plasma light-up in gas openings, protecting o-rings and extending the lifetime of the plasma source by minimizing defects and fluorine outgassing, enhancing the reliability of the microwave plasma processing process.
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 conductive insert is disposed within at least one of the dielectric faceplate gas openings or adjacent o-rings included in the plasma showerhead assemblies.