Silicon Carbide Gradient Coating for Plasma-Etched Chamber Parts
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Solution Overview
Problem
Semiconductor processing equipment components face erosion and contamination due to plasma etching processes, leading to reduced lifespan and affected wafer characteristics and yield, as existing protective layers lack durability and adhesion.
Innovation Solution
A method involving a hollow cathode unit with silicon targets to produce silicon carbide compound films with a controlled silicon-to-carbon atomic ratio, applied as a protective coating on equipment components, enhancing plasma resistance and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional protective layers are formed on substrates of equipment parts, then the parts can be reused after old protective layers are damaged, but the protecting layers are easily peeled off due to interlayer stress and lattice mismatch
Solution Approach 1:
The patent changes the compositional parameters of the protective layer by creating a gradient structure where silicon content decreases and carbon content increases from the substrate interface toward the outer surface. This parameter gradient resolves the adhesion problem by providing better lattice matching at the interface while maintaining plasma resistance at the surface.
Solution Approach 2:
The patent creates a composite protective layer with non-uniform composition, combining silicon-rich regions near the substrate for strong adhesion with carbon-rich regions at the surface for plasma resistance. This composite structure with spatially varying composition solves both adhesion and durability issues simultaneously.
2Manufacturing precision
If plasma etching process is used to etch silicon wafer, then anisotropic etching and high selectivity are achieved, but the plasma atmosphere erodes vacuum pipelines, gas nozzles, vacuum chambers and components inside equipment
Solution Approach 1:
The patent applies a silicon carbide protective coating on equipment components that acts as an intermediary barrier between the plasma atmosphere and the base materials. This coating withstands plasma erosion while allowing the plasma etching process to continue effectively on silicon wafers, thus protecting components without interfering with the etching precision.
3Productivity
If plasma etching is performed in low-pressure environment with fluorine-containing or chlorine-containing gases, then etching rate can be controlled, but dust or particles are produced that contaminate silicon wafer and affect yield
Solution Approach 1:
The patent converts the harmful plasma erosion that produces dust and particles into a beneficial protective effect. By applying a durable silicon carbide coating, the plasma energy is consumed in eroding the coating rather than producing contaminating particles, thus protecting the wafer while maintaining controlled etching rates.
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 silicon carbide compound films demonstrate high plasma resistance, extending equipment lifespan, preventing contamination, and improving wafer characteristics and yield by providing a durable and adherent protective layer.
Implementation Method 1
applying a plasma power to the two silicon targets to ignite a hollow cathode discharge silicon plasma
Implementation Method 2
introducing a sputtering gas through the slit inlet to blow out the hollow cathode discharge silicon plasma
Implementation Method 3
reacting the hollow cathode discharge silicon plasma with the introduced gases to form silicon carbide compound films
Data Source
AI summary
A part is adapted to be used in a semiconductor processing equipment. The part includes a substrate and a protective coating. The protective coating covers at least a part of the substrate, is made of silicon carbide, and has an atomic ratio of carbon in the protective coating increases in a direction away from the substrate while an atomic ratio of silicon in the protective coating decreases in the direction. The atomic ratio of silicon in the protective coating is larger than that of the carbon near the substrate, and the atomic ratio of silicon in the protective coating is smaller than that of carbon near the outer surface of the protective coating. A method for making the part is also provided.