YAG Sintered Surface Finishing for Plasma-Resistant Gas Nozzles
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Solution Overview
Problem
Existing YAG sintered bodies used in semiconductor manufacturing equipment face issues with plasma resistance, particularly due to machining damage and aluminum oxide segregation, leading to particle detachment and difficulty in controlling shrinkage during firing for complex or small-sized flow channels.
Innovation Solution
A YAG sintered body with a surface featuring intragranular pores, arithmetic average roughness Ra ≤ 0.5 μm, and Rv/Rz ≤ 0.7, processed to improve plasma resistance, and heat treated at 1400° C. to 1700° C. for 1 hour, reducing the risk of particle generation and ensuring precise structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the YAG sintered body surface is machined to achieve desired shape or surface roughness, then the shape precision is improved, but machining damage increases the risk of particle detachment due to plasma
Solution Approach 1:
The patent applies preliminary action by performing surface processing (grinding or polishing) to reduce surface roughness to Ra≤1μm before the sintered body is exposed to plasma. This preliminary surface treatment removes machining damage and creates a smooth surface that resists particle detachment during subsequent plasma exposure, thus resolving the contradiction between achieving precise shapes and preventing particle detachment
Solution Approach 2:
The patent changes the surface roughness parameter to Ra≤1μm through controlled grinding or polishing processes. By optimizing this surface roughness parameter, the patent achieves both precise shaping and reduced particle detachment risk, as the smooth surface minimizes stress concentration points where particles could detach under plasma exposure
2Ease of manufacture
If Al2O3 segregates at grain boundaries during sintering, then the sintering process is simplified, but plasma resistance decreases at grain boundaries
Solution Approach 1:
The patent applies local quality by creating a surface layer with different composition from the bulk material. The surface layer is enriched with YAG phase and depleted of segregated Al2O3 through controlled sintering and surface treatment, while the interior maintains the simpler segregated structure. This local differentiation ensures high plasma resistance at the surface where it is most needed, while allowing simplified manufacturing in the bulk
Solution Approach 2:
The patent creates a composite structure with a YAG-enriched surface layer and an Al2O3-containing bulk material. This composite architecture provides high plasma resistance at the surface through the YAG-rich layer, while the bulk material maintains manufacturing simplicity through controlled Al2O3 segregation, thus resolving the contradiction between ease of manufacture and plasma resistance
3Object-affected harmful factors
If the surface is left as-sintered to avoid machining, then particle detachment is reduced, but complex flow channels or small-sized members with narrow channels cannot be accurately formed
Solution Approach 1:
The patent applies preliminary action by performing surface processing to reduce surface roughness to Ra≤1μm before plasma exposure. This preliminary treatment removes machining damage and creates a smooth surface that resists particle detachment, while still allowing complex flow channels to be accurately formed through the controlled processing
Solution Approach 2:
The patent applies partial action by selectively processing only the surface layer to reduce roughness, while leaving the bulk material structure unchanged. This partial surface treatment achieves both flow channel accuracy and particle detachment resistance without the need for excessive machining that would create damage
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 processed YAG sintered body exhibits enhanced plasma resistance and reduced particle detachment, suitable for complex or small-sized semiconductor manufacturing equipment components like gas nozzles, without requiring strict shrinkage control during firing.
Implementation Method 1
heat treating the sintered body at 1000° C. to 1550° C. for 0.1 to 6 hours
Implementation Method 2
a YAG sintered body includes a predetermined surface where intragranular pores are exposed
Data Source
AI summary
A YAG sintered body has a predetermined surface where intragranular pores are exposed. On the predetermined surface, arithmetic average roughness Ra satisfies Ra≤0.5 μm, and a ratio between maximum height Rz and maximum valley depth Rv satisfies Rv/Rz≤0.7. With this configuration, the predetermined surface of a processed surface is smoothed to have improved plasma resistance and exhibit a particle-suppressing effect.