Yttrium Granular Powder for Dense Thermal Spray Coatings
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Solution Overview
Problem
Conventional thermal spray coating methods, such as suspension plasma spraying and physical vapor deposition, face challenges in achieving high-density coatings with low porosity and high plasma resistance, which are essential for semiconductor manufacturing, due to issues like high manufacturing costs, limited coating thickness, and particle agglomeration, leading to defects in semiconductor wafers.
Innovation Solution
A yttrium-based granular powder for thermal spraying is developed, comprising yttrium compounds like Y2O3 and SiO2, with a Y—Si—O intermediate phase, that is calcined at 1200-1450°C to reduce porosity and enhance plasma resistance, allowing for a dense thermal spray coating with improved durability and reduced etching rates during semiconductor manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermal spray coating methods (suspension plasma spraying, physical vapor deposition) are used, then coating can be applied to semiconductor chamber members, but the coating has high porosity and low plasma resistance, leading to particle generation during dry etching
Solution Approach 1:
The patent uses a composite coating material comprising yttrium oxide (Y2O3) as the base ceramic material combined with silica (SiO2) particles. This composite structure leverages the high melting point and plasma resistance of Y2O3 while incorporating SiO2 to fill pores and reduce porosity, achieving both high plasma resistance and high coating density simultaneously
Solution Approach 2:
The patent controls the particle size distribution of the thermal spray material, specifying that 60-80 wt% of particles should be in the 1-5 μm range and 20-40 wt% in the 5-10 μm range. This precise parameter control of particle size enables optimal packing density and reduced porosity in the coating, resolving the contradiction between coating density and plasma resistance
2Manufacturing precision
If high-density coating is achieved through conventional methods, then porosity is reduced, but manufacturing cost increases and coating thickness is limited
Solution Approach 1:
The patent employs conventional atmospheric plasma spray equipment rather than expensive specialized equipment like suspension plasma spray or physical vapor deposition systems. The thermal spray material is designed as a simple mixture of Y2O3 and SiO2 particles without complex formulations, reducing material cost while achieving high-density coatings through optimized particle size distribution
Solution Approach 2:
The patent performs preliminary classification of particles by size before spraying, ensuring that 60-80 wt% of particles are in the 1-5 μm range and 20-40 wt% are in the 5-10 μm range. This pre-sorting enables optimal packing and reduced porosity during the spraying process itself, achieving high density without requiring multiple coating passes or post-processing, thereby reducing manufacturing cost
3Reliability
If thermal spray coating is applied to protect chamber members from plasma erosion, then plasma resistance is improved, but particle detachment occurs during dry etching, causing defects on semiconductor wafers
Solution Approach 1:
The patent intentionally incorporates silica particles and creates a controlled porous structure in the coating that prevents particle detachment. The SiO2 particles fill voids and create a interlocking structure that anchors the coating to the substrate, reducing the generation of detachable particles during dry etching while maintaining plasma erosion resistance
Solution Approach 2:
The silica (SiO2) particles act as an intermediary material between the Y2O3 ceramic matrix and the substrate. During thermal spraying, SiO2 particles with lower melting point than Y2O3 facilitate bonding and create a gradient structure that reduces thermal stress and prevents particle detachment, thereby reducing harmful particle generation during subsequent dry etching processes
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 yttrium-based granular powder results in a high-density thermal spray coating with reduced porosity and improved plasma resistance, minimizing particle generation and enhancing the yield of semiconductor wafers by suppressing detachment phenomena during dry etching processes.
Implementation Method 1
thermal spray particles including a material such as ceramics are sprayed on the surface of a substrate in a softened or molten state using combustion or electric energy
Implementation Method 2
thermal spray particles including a material such as ceramics are sprayed on the surface of a substrate in a softened or molten state
Implementation Method 3
As the sprayed molten powder is rapidly cooled, the molten powder is solidified and layered on the coating target surface
Implementation Method 4
the sprayed molten powder is rapidly cooled, the molten powder is solidified
Implementation Method 5
a thermal spray coating of ceramic having plasma erosion resistance is provided on a member exposed to plasma of oxygen gas or halogen gas for the purpose of reducing the generation of particles
Implementation Method 6
as the density of the coating inside of the thermal spray coating of ceramics is increased, the degree of adsorption of CFx-based process gases may be reduced due to defects such as pores in the dry etching process
Data Source
AI summary
The present disclosure relates to an yttrium-based granular powder for thermal spraying. More particularly, the yttrium-based granular powder is a mixture including one or more yttrium compound powders selected from among Y2O3, YOF, YF3, Y4Al2O9, Y3Al5O12, and YAlO3, and a silica (SiO2) powder. A Y—Si—O intermediate phase is included therein in a content of less than 10 wt %. The thermal spray coating manufactured using the same has a low porosity, and forms a very dense thin film, thus ensuring excellent plasma resistance.