Cover Ring Carbon Coating for Plasma Erosion Control
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Solution Overview
Problem
Erosion of plasma processing chamber components, particularly the cover ring, leads to contamination and non-uniform etching due to the bending of the plasma sheath, reducing the mean time between maintenance and affecting processing quality.
Innovation Solution
A ring assembly with a carbon-based coating, thicker on the inner portion, is applied to the cover ring to enhance erosion resistance and maintain plasma sheath consistency, using biased ion energy and temperature control to form a denser and more resistant coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform thickness coating is applied to the cover ring, then the manufacturing process is simple, but the inner portion erodes faster due to higher ion bombardment intensity
Solution Approach 1:
The patent applies a non-uniform coating thickness distribution to the cover ring, with the inner portion receiving a thicker coating than the outer portion. This local quality variation matches the non-uniform ion bombardment intensity, providing enhanced protection where needed most while maintaining overall reliability.
2Reliability
If the cover ring is left uncoated, then the manufacturing cost is low, but erosion from ion bombardment contaminates the chamber and reduces component life
Solution Approach 1:
The patent applies a carbon-based coating that can be deposited using relatively simple and cost-effective techniques. While the coating adds some manufacturing complexity, it significantly extends component life and reduces contamination, making the overall system more economical by reducing maintenance frequency and improving processing quality.
3Manufacturing precision
If the cover ring erodes, then maintenance frequency increases, but the erosion also causes plasma sheath bending that degrades etching uniformity
Solution Approach 1:
The patent applies a protective carbon-based coating to the cover ring before it is subjected to ion bombardment. This preliminary protective action prevents erosion from occurring in the first place, thereby maintaining plasma sheath horizontal consistency and etching uniformity over extended periods, and reducing the frequency of maintenance interventions.
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 solution extends the mean time between maintenance, reduces contamination, and ensures etching uniformity by maintaining the plasma sheath's horizontal consistency, thereby improving processing quality and throughput.
Implementation Method 1
Ions from the plasma gas formed in the chamber are biased by the cathode to target the substrate. During etching, the ions from the plasma tend to impact the substrate disposed on the substrate support at an angle normal to the plasma sheath.
Implementation Method 2
Over time, process equipment such as the cover ring, tend to erode from the ion bombardment.
Implementation Method 3
A plasma is formed from a mixture of process gases provided to the processing chamber.
Implementation Method 4
A plasma is formed from a mixture of process gases provided to the processing chamber.
Data Source
AI summary
A ring assembly for a substrate support is disclosed herein. The ring assembly has a ring shaped body. The ring shaped body has an inner diameter and an outer diameter, a top surface, an inner portion at the inner diameter, and an outer portion at the outer diameter. A carbon based coating is disposed on the top surface of the ring shaped body, wherein the carbon based coating is thicker on the inner portion of the ring shaped body than the outer portion of the ring shaped body.