Fluoride Thermal Spray Coating for Plasma Erosion Resistance
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Solution Overview
Problem
Existing thermal spray coatings for plasma etching devices lack long-term plasma erosion resistance, leading to potential defects in semiconductor devices due to particle adhesion and reduced device lifespan.
Innovation Solution
A thermal spray material comprising a composite compound with a rare earth fluoride content of 40-80 mol%, magnesium fluoride content of 10-40 mol%, and calcium fluoride content of 0-40 mol%, which forms a coating with a crystalline and amorphous phase structure, providing enhanced plasma erosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermal spray coating is provided to protect members from plasma erosion, then plasma erosion resistance is improved, but the coating may generate particles that adhere to semiconductor substrates causing defects
Solution Approach 1:
The patent uses a composite coating system consisting of a buffer layer (alumina or aluminum alloy) and a top layer (fluoride ceramics such as CaF2, MgF2, YF3, AlF3, or CeF3). This composite structure allows the buffer layer to provide mechanical strength and erosion resistance while the top layer provides low particle generation and high plasma resistance, thereby resolving the contradiction between erosion resistance and particle generation.
Solution Approach 2:
The patent applies different materials with different properties to different layers of the coating. The buffer layer near the substrate provides mechanical support and erosion resistance, while the top layer in direct contact with plasma provides low particle generation. This local differentiation of material properties allows each layer to optimize its function, reducing overall particle generation while maintaining plasma erosion resistance.
2Duration of action of stationary object
If existing thermal spray coatings are used to protect plasma etching device members, then short-term plasma erosion resistance is achieved, but long-term protection and stable device production are compromised
Solution Approach 1:
The composite coating structure with a buffer layer and a top layer of fluoride ceramics provides both short-term and long-term plasma erosion resistance. The buffer layer prevents substrate degradation while the top layer maintains low particle generation over extended periods, ensuring stable device production and extended coating lifespan.
Solution Approach 2:
The patent specifies precise compositional parameters for the coating materials, including the use of specific fluoride ceramics (CaF2, MgF2, YF3, AlF3, CeF3) and controlled particle size distributions. These parameter optimizations ensure the coating maintains its protective properties and low particle generation characteristics over long-term exposure to plasma, thereby achieving both extended lifespan and stable device production.
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 thermal spray coating effectively protects plasma etching device components from long-term plasma erosion, ensuring stable device production and extended component lifespan by maintaining a porosity of 2.0% or less and crystallinity of 1-75%.
Implementation Method 1
the member exposed to the reactive plasma in the chamber has been protected from plasma erosion by providing the member with a thermal spray coating having high plasma erosion resistance
Implementation Method 2
providing a layer containing dense fluoride ceramics mainly containing at least one selected from CaF2, MgF2, YF3, AlF3, and CeF3 as the thermal spray coating
Data Source
AI summary
There is provided a thermal spray coating which has excellent plasma erosion resistance, which protects members of a plasma etching device from plasma erosion over a long period of term, and which can contribute to the stable production of devices and a longer life of members. The thermal spray material which is one aspect of this invention contains a composite compound containing a rare earth fluoride in the proportion of 40 mol % or more and 80 mol % or less, a magnesium fluoride in the proportion of 10 mol % or more and 40 mol % or less, and a calcium fluoride in the proportion of 0 mol % or more and 40 mol % or less.