MgO-Based Ceramic Film Corrosion Resistance via Al Solid Solution
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Solution Overview
Problem
Existing MgO-based ceramic films used in semiconductor manufacturing are prone to corrosion due to high water absorption and excessive MgO content, leading to reduced corrosion resistance and increased etching rates.
Innovation Solution
A MgO-based ceramic film is developed with a high MgO/Al2O3 mass ratio of more than 2.33, where Al is dissolved in MgO to form a solid-solution, resulting in improved corrosion resistance and reduced water absorption, achieved through thermal spraying of a mixture of MgO and Al2O3 granules heat-treated at 1200°C or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the MgO content in the ceramic film is increased to improve corrosion resistance, then the water absorption increases and corrosion resistance deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the MgO/Al2O3 mass ratio to exceed 2.33 and controlling the crystal grain size to 3 μm or less. This specific parameter range creates a unique condition where high MgO content provides corrosion resistance while the fine grain structure prevents excessive water absorption, resolving the contradiction between these two properties
Solution Approach 2:
The patent uses a composite spinel-type ceramic material containing both MgO and Al2O3 in a specific ratio. The combination of these two materials creates a synergistic effect where Al2O3 reinforces the structure and reduces water absorption while MgO provides corrosion resistance, allowing the composite to overcome the limitations of either material alone
2Reliability
If the MgO/Al2O3 mass ratio is increased beyond 2.33 to improve corrosion resistance, then the etching rate increases and corrosion resistance decreases
Solution Approach 1:
The patent identifies and exploits a critical threshold parameter: the MgO/Al2O3 mass ratio of 2.33 and crystal grain size of 3 μm. By controlling these parameters within specific ranges, the patent achieves a breakthrough where ratios exceeding 2.33 provide enhanced corrosion resistance without the previously observed increase in etching rate, as the fine grain structure compensates for the high MgO content
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 MgO-based ceramic film exhibits superior corrosion resistance and lower water absorption, maintaining high corrosion resistance while minimizing etching rates, making it suitable for semiconductor manufacturing apparatus components.
Implementation Method 1
Al is dissolved in MgO to form a solid-solution
Implementation Method 2
heat-treating the granules at 1200° C. or more
Implementation Method 3
thermally spraying the thermal spray raw material onto a substrate to form the MgO-based ceramic film
Data Source
AI summary
A MgO-based ceramic film according to the present invention contains crystalline phases of MgO and MgAl2O4, and Al is dissolved in the MgO to form a solid-solution. The ceramic film exhibits a diffraction peak representing the (200) plane of MgO at an angle 2θ of more than 42.92° in CuKα XRD measurement. A shoulder preferably appears on the higher angle side of the peak representing the (200) plane of MgO. The mass ratio MgO/Al2O3 of MgO to Al2O3 converted from Mg and Al in terms of oxides is preferably higher than 2.33.