Yttrium Oxyfluoride Coating Phase Stability
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Solution Overview
Problem
Yttrium fluoride coatings used in semiconductor production apparatuses undergo phase changes when exposed to heat, leading to microcracks and particle generation, while yttrium oxyfluoride coatings may contain yttrium fluoride and oxide phases that are unstable under plasma conditions, causing further issues.
Innovation Solution
A yttrium oxyfluoride sprayed coating with a total intensity of peaks attributable to yttrium oxyfluoride set at 100, ensuring that peaks for yttrium fluoride and yttrium oxide are less than 10, forming a single-phase coating that is stable against heat and plasma, and a method involving plasma spraying with specific oxygen content and conditions to achieve this.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If yttrium fluoride coating is sprayed, then corrosion resistance is improved, but phase change occurs under heat exposure causing microcracks and particle generation
Solution Approach 1:
The patent changes the chemical composition parameters by using yttrium oxyfluoride instead of pure yttrium fluoride, and controls the oxygen content at 7.0-11.5 mass% to stabilize the crystal phase and prevent phase transformation under heat exposure
Solution Approach 2:
The patent creates a composite coating system where yttrium oxyfluoride serves as the base material with controlled oxygen content, forming a multi-phase stable structure that combines the benefits of fluoride corrosion resistance with oxide phase stability
2Stability of the object's composition
If yttrium oxide is included in the coating, then stability is improved, but fluorination by fluorine plasma causes volume expansion or shrinkage leading to particle generation
Solution Approach 1:
The patent optimizes the oxygen content parameter within a specific range (7.0-11.5 mass%) to create yttrium oxyfluoride with stable crystal structure that resists fluorination by fluorine plasma, thereby preventing volume changes and particle generation
Solution Approach 2:
The patent creates a coating with non-uniform oxygen distribution at the molecular level, where the controlled oxygen content is locally optimized to prevent both phase transformation and fluorination reactions
3Ease of manufacture
If material containing only yttrium fluoride is sprayed, then coating formation is simplified, but heterogeneous phase generation occurs requiring preheating or heat treatment
Solution Approach 1:
The patent incorporates oxygen content as a new control parameter in the material composition, transforming the simple yttrium fluoride into yttrium oxyfluoride with 7.0-11.5 mass% oxygen, which eliminates the need for complex preheating or heat treatment 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 solution prevents microcrack formation and particle generation, providing a stable and adherent coating for semiconductor production apparatuses, enhancing the durability and quality of the coatings.
Implementation Method 1
a step of performing plasma spraying using a powder (granule) material containing yttrium oxyfluoride
Data Source
AI summary
An yttrium oxyfluoride sprayed coating contains Y5O4F7 as a main component. In the yttrium oxyfluoride sprayed coating, when the total intensity of all peaks attributable to yttrium oxyfluoride in a diffraction spectrum obtained by X-ray diffractometry is assumed to be 100, the total intensity of all peaks attributable to yttrium fluoride and yttrium oxide is less than 10. Furthermore, in an yttrium oxyfluoride-containing sprayed coating, when the total intensity of all peaks attributable to yttrium oxyfluoride and yttrium fluoride in a diffraction spectrum obtained by X-ray diffractometry is assumed to be 100, the total intensity of all peaks attributable to yttrium oxide is less than 1.