Yttrium Fluoride Chamber Coating for Low-Particle Plasma Processing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional plasma processing techniques fail to adequately suppress the generation of fine particles, leading to contamination and reduced processing yield due to insufficient consideration of conditions for forming coating films using yttrium fluoride, which react with fluorine-based plasma and wear out, causing corrosion and particle generation.
Innovation Solution
A plasma processing apparatus with a coating film composed of yttrium fluoride or a material containing yttrium fluoride, where the orthorhombic crystal ratio is 60% or more and the crystal size is 50 nm or smaller, is formed on the inner wall surface of the processing chamber, and the surface is treated at 280°C or higher and 350°C or lower to reduce particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If atmospheric plasma spraying method is used to form coating film, then coating film can be formed on base member surface, but surface unevenness is large and pores are formed between grains
Solution Approach 1:
The patent changes the fundamental parameters of the coating formation process by switching from atmospheric plasma spraying to aerosol deposition method. This involves changing the deposition mechanism from molten/semi-molten state to near-room temperature deposition, and changing the particle delivery method from plasma flame to supersonic gas flow. These parameter changes result in dense, pore-free coating films with smooth surfaces.
Solution Approach 2:
The patent replaces the thermal-mechanical atmospheric plasma spraying process with a supersonic aerosol deposition process. Instead of using plasma flame heating and mechanical spraying, the invention uses controlled supersonic gas flow to deliver particles that deposit conformally on the substrate surface, eliminating the pore formation and surface roughness issues.
2Productivity
If coating film is exposed to fluorine-based plasma, then plasma processing can be performed, but coating film reacts with fluorine and wears out causing particle generation
Solution Approach 1:
The patent uses composite material structure with multiple layers: a buffer layer (yttrium oxide or aluminum oxide) and a fluorinated compound coating layer (yttrium fluoride or aluminum fluoride). This composite structure allows the buffer layer to provide mechanical strength and adhesion while the fluorinated layer provides plasma resistance, preventing particle generation during fluorine-based plasma processing.
Solution Approach 2:
The patent applies preliminary protective action by forming a buffer layer before applying the fluorinated compound coating. This buffer layer pre-prepares the substrate surface, providing a stable base that prevents direct interaction between the metal substrate and fluorine plasma, thereby preventing corrosion and particle generation during subsequent plasma processing.
3Reliability
If yttrium oxide coating film is used, then plasma resistance is improved, but surface roughness increases and particles are generated
Solution Approach 1:
The patent uses an intermediary fluorinated compound coating layer (yttrium fluoride or aluminum fluoride) over the yttrium oxide buffer layer. This intermediary layer maintains the plasma resistance provided by the yttrium oxide while eliminating the surface roughness and particle generation issues, as the fluorinated compound forms a smoother, more stable surface under fluorine-based plasma conditions.
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 effectively suppresses the generation of particles, improving processing yield by maintaining the integrity of the coating film and reducing contamination, thereby enhancing the precision and reliability of plasma etching processes.
Implementation Method 1
an atmospheric plasma spraying method is a technique of introducing raw material powder having a predetermined particle diameter, for example, a diameter in the range of 10 to 60 μm, into a plasma flame together with a transport gas to form a molten or semi-molten state and spraying raw material particles in such a state onto a surface of a base member to be coated to form a film
Implementation Method 2
a so-called aerosol deposition method is disclosed. This technique forms a film by blowing raw material powder having a diameter of about several μm onto the surface of the substrate to be coated at speed close to the speed of sound to form a layered structure having microcrystals with a size of 8 to 50 nm as a coating film
Implementation Method 3
When being exposed to plasma of a fluorine-based gas, the coating film made of yttrium oxide reacts with fluorine and the like in the plasma and the coating film is worn out. Therefore, a change of the coating film to yttrium fluoride has been studied.
Data Source
AI summary
A plasma processing apparatus includes: a processing chamber disposed inside a vacuum container and in which plasma is formed; and a member which is a member forming an inner wall surface of the processing chamber and is disposed on a surface to be exposed to the plasma and has a coating film formed by spraying of yttrium fluoride or a material containing the yttrium fluoride. A ratio of an orthorhombic crystal of the yttrium fluoride or the material containing the yttrium fluoride forming the coating film relative to the entirety is 60% or more.