Ceramic Gas Nozzle with Graded Crystal Structure for Plasma Resistance
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Solution Overview
Problem
In plasma devices used for semiconductor and liquid crystal manufacturing, the exposure of ceramic sintered body surfaces in gas nozzles to plasma-converted gases leads to surface damage and particle fallout, which can result in object failure due to adhered particles.
Innovation Solution
A gas nozzle with a ceramic sintered body having a through hole with distinct regions: a first region near the outlet with larger average crystal grain size for increased plasma resistance and a second region further inward with smaller grain size for enhanced mechanical strength, reducing particle fallout and adhesion to the object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ceramic sintered body surface is exposed to plasma-converted gas, then gas supply function is achieved, but the surface is damaged and particles fall off
Solution Approach 1:
The patent applies local quality by creating distinct crystal grain size regions within the ceramic sintered body. The first region near the outlet has larger crystal grains (10-50 μm) for plasma resistance, while the second region further inward has smaller crystal grains (1-10 μm) for mechanical strength. This spatial differentiation of material properties resolves the contradiction between plasma exposure resistance and particle fallout prevention.
Solution Approach 2:
The patent employs composite material structure by combining ceramic grains of different sizes within the sintered body. The composite nature of having both large-grain and small-grain regions creates a material that simultaneously exhibits plasma resistance from the large grains and mechanical integrity from the small grains, preventing particle fallout while maintaining gas supply function.
2Reliability
If the ceramic sintered body has large crystal grain size for plasma resistance, then plasma resistance increases, but mechanical strength may decrease
Solution Approach 1:
The patent resolves this contradiction by applying local quality through spatial differentiation of crystal grain sizes. The first region with larger grains (10-50 μm) provides plasma resistance where needed, while the second region with smaller grains (1-10 μm) provides mechanical strength in areas requiring structural integrity. This localized property assignment allows both requirements to be satisfied simultaneously in different regions of the same component.
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 design effectively increases plasma resistance in the exposed region, reducing particle fallout and object failure by minimizing particle adhesion, while maintaining mechanical strength and accuracy in the less exposed region.
Implementation Method 1
Average crystal grain size in the first region is larger than average crystal grain size in the second region... it is possible to increase plasma resistance in the first region that is likely to be exposed to plasma-converted gas
Implementation Method 2
a discharge member that converts the gas into plasma by discharge
Data Source
AI summary
A gas nozzle according to an embodiment of the present invention includes a columnar main body including a ceramic sintered body having a through hole through which gas flows. An outlet of the through hole for the gas is formed on one end face of the main body. An inner wall of the through hole has a first region located in a vicinity of the outlet, and a second region located further inward of the main body than the first region. The first region and the second region each include a sintered surface of the ceramic sintered body. Average crystal grain size in the first region is larger than average crystal grain size in the second region.