Polycrystalline CaF2 Focusing Ring via Pressure Bonding
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Solution Overview
Problem
Adhesives or band members used in joining components of plasma treatment devices can contaminate the system, and existing methods face challenges in producing large-sized focusing rings with high material and manufacturing yield while maintaining corrosion resistance and workability.
Innovation Solution
A polycrystalline CaF2 member is created by pressure bonding multiple CaF2 partial members with a relative density of 94% or higher and a mean particle diameter of 200 μm or greater, forming a focusing ring that is resistant to plasma etching and easy to manufacture in larger sizes without using contaminating materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesives or band members are used to join components of plasma treatment devices, then the components can be assembled together, but contamination of the system occurs
Solution Approach 1:
The patent removes adhesives and band members from the joining process entirely, replacing them with a mechanical interference fit system where the focusing ring is directly inserted into the electrostatic chuck without any bonding materials, thereby eliminating the contamination source
Solution Approach 2:
The patent introduces a tapered insertion portion as an intermediary mechanical feature that enables secure joining through geometric interlocking rather than chemical bonding, allowing assembly without contaminants while maintaining structural integrity
2Productivity
If existing methods are used to produce focusing rings, then manufacturing is possible, but material and manufacturing yields are low and large-sized production is difficult
Solution Approach 1:
The patent divides the focusing ring into multiple segmented members that can be independently manufactured and then assembled, enabling production of large-sized rings with high material yield while maintaining manufacturing efficiency
Solution Approach 2:
The patent changes the material parameters by using polycrystalline CaF2 with controlled grain size (200 μm or greater) and high relative density (94% or greater), which improves both manufacturability and performance while enabling larger component sizes
3Reliability
If polycrystalline CaF2 with high relative density and large grain size is used, then corrosion resistance and workability are improved, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes material parameters by specifying polycrystalline CaF2 with controlled grain size (200 μm or greater) and relative density (94% or greater), achieving improved corrosion resistance and workability through material science advancements rather than complex manufacturing processes
Solution Approach 2:
The patent performs preliminary actions by pre-manufacturing segmented members with precisely controlled material properties and tapered geometries before final assembly, simplifying the overall manufacturing process while ensuring high reliability
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 provides a focusing ring with excellent corrosion resistance and workability, preventing contamination and enabling the production of larger sizes with improved material and manufacturing yields, thus addressing the challenges of contamination and scalability in existing technologies.
Implementation Method 1
a combined assembly of a plurality of polycrystalline bodies made from CaF2 that are pressure bonded together
Implementation Method 2
a holding temperature when pressure bonding together the plurality of partial members is between 1000° C. and 1200° C. inclusive
Data Source
AI summary
A polycrystalline CaF2 member includes a combined assembly of a plurality of polycrystalline bodies made from CaF2 that are pressure bonded together.