Bubble-Controlled Si-Based Glass for Plasma Etching Durability
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Solution Overview
Problem
Quartz glass members used in plasma etching processes for semiconductor and liquid crystal production suffer from thickness reduction due to etching by halide gases, leading to decreased durability and potential abnormal electrical discharge, while alternative materials like alumina and yttrium-aluminum-garnet sintered bodies result in decreased yields and increased costs.
Innovation Solution
A glass composition comprising Si and at least one di- or higher-valent metal element, produced by pressurizing a melt of these oxides in a He or inert gas atmosphere, ensuring no bubbles larger than 0.1 mm and an occupied area fraction of smaller bubbles is 0.05% or less, maintaining high plasma resistance and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If quartz glass members are used in plasma etching processes, then good radio-frequency permeability and complicated shape production are achieved, but thickness reduction occurs due to etching by halide gases
Solution Approach 1:
The invention changes the chemical composition parameters of the glass by incorporating specific metal elements (Al, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) in controlled amounts to modify the glass structure and reduce plasma etching rates while maintaining manufacturability
Solution Approach 2:
The invention creates a composite glass material combining SiO2 base with multiple metal oxides to achieve both durability against plasma etching and ease of manufacturing complicated shapes, resolving the contradiction between material performance and manufacturability
2Reliability
If alumina sintered bodies are used to reduce plasma etching, then plasma resistance is improved, but particle detachment occurs from crystal grain boundaries
Solution Approach 1:
The invention changes from a sintered ceramic structure to a glass structure by controlling composition and thermal processing parameters, eliminating crystal grain boundaries that cause particle detachment while maintaining plasma resistance through compositional design
Solution Approach 2:
The glass structure provides homogeneous composition without crystal grain boundaries, preventing particle detachment issues that occur in sintered bodies with heterogeneous microstructures
3Reliability
If high purity raw material powders are used for alternative materials, then plasma resistance is improved, but production cost increases
Solution Approach 1:
The invention optimizes composition parameters to achieve plasma resistance using commercially available raw materials with standard purity levels, avoiding the need for expensive high-purity powders while maintaining performance
4Reliability
If alumina materials are used instead of quartz glass, then plasma etching rate is reduced, but workability decreases
Solution Approach 1:
The invention adjusts compositional parameters to achieve plasma resistance comparable to alumina while maintaining the workability advantages of glass materials through lower melting temperatures and better formability
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 glass exhibits high durability and plasma resistance, reducing wear and preventing abnormal electrical discharge, while maintaining high purity and workability, suitable for semiconductor and liquid crystal production apparatuses.
Implementation Method 1
pressurizing a melt of an oxide of Si and at least one di- or higher-valent metal element in a He gas atmosphere or by heating the melt in an inert gas atmosphere other than a He gas atmosphere and then pressurizing the melt in the inert gas atmosphere
Implementation Method 2
a glass containing relatively large amounts of Al and Y has high plasma resistance
Data Source
AI summary
Methods for producing a glass that contains no bubbles with diameters of more than 0.1 mm and in which the occupied area fraction of bubbles with diameters of 0.1 mm or less is 0.05% or less, the methods including: placing raw material powders for at least one oxide of Si and a di- or higher-valent metal element in a container, mixing the raw material powders together and then melting the mixture by heating under reduced pressure to obtain a melt; pressurizing the melt in a He gas atmosphere, or heating the melt in an inert gas atmosphere other than a He gas atmosphere and then pressurizing the melt in the inert gas atmosphere; and cooling the melt.