SiC Showerhead RF Coupling and Erosion Management
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Solution Overview
Problem
Capacitive-coupled plasma chambers require RF energy coupling properties opposite to those provided by sintered/CVD SiC, making it unsuitable for commercial use, and existing showerheads are consumable and not reusable due to plasma erosion.
Innovation Solution
A showerhead made of low electrical resistivity bulk material, such as sintered SiC, coated with CVD SiC, with gas holes drilled using an ultrasound machine, allowing for efficient RF coupling and reusability by managing CVD coating erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If sintered/CVD SiC is used for the showerhead in capacitive-coupled plasma chambers, then mechanical strength and purity are improved, but RF energy coupling efficiency deteriorates due to high electrical resistivity
Solution Approach 1:
The showerhead employs a composite structure combining sintered SiC bulk material with a CVD SiC coating layer. The sintered SiC provides mechanical strength and structural integrity, while the CVD SiC coating provides the necessary electrical conductivity for RF coupling in capacitive-coupled plasma chambers. This composite approach allows both materials to contribute their advantageous properties to the final component.
2Use of energy by moving object
If single or poly-crystalline doped Silicon is used for showerhead, then RF coupling is improved, but plasma erosion causes the showerhead to be consumable and non-reusable
Solution Approach 1:
The combination of sintered SiC bulk and CVD SiC coating creates a composite material that resists plasma erosion while maintaining RF coupling capability. The SiC material exhibits superior resistance to plasma erosion compared to silicon-based materials, enabling the showerhead to be reused multiple times without significant degradation from plasma erosion.
Solution Approach 2:
The invention changes the material composition parameters by using high-purity sintered SiC with controlled doping levels and CVD coating thickness. These parameter changes optimize both the electrical conductivity for RF coupling and the resistance to plasma erosion, transforming the showerhead from a consumable component to a reusable one.
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
Enables effective RF energy coupling in capacitive-coupled plasma chambers and extends the lifespan of the showerhead by reusing it after managing CVD coating erosion, reducing costs and improving operational efficiency.
Implementation Method 1
a CVD SiC coating provided on an interior side of the showerhead
Implementation Method 2
gas holes drilled using an ultrasound machine
Data Source
AI summary
A showerhead for use in a capacitively-coupled plasma chamber and made of low resistivity bulk layer coated with CVD SiC. The bulk low resitivity material may be, for example, graphite, Silicon Carbide (SiC), converted graphite, SiC+C, etc. Sintered SiC may be used as the bulk material coated with CVD SiC to provide a showerhead that is suitable for use in a capacitively-coupled plasma chamber.