Composite Sintered Body Composition for Stable Electrostatic Chucks
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Solution Overview
Problem
Semiconductor manufacturing apparatus members, such as electrostatic chucks, face challenges with abnormal grain growth of aluminum oxide, low corrosion resistance, high dielectric loss, and insufficient withstand voltage due to fine SiC particles and impurities in existing dielectric materials, leading to surface unevenness, particle fall-off, and potential dielectric breakdown.
Innovation Solution
A composite sintered body comprising aluminum oxide, β-type silicon carbide, and magnesium-aluminum composite oxide with a spinel-type crystal structure is developed, with controlled particle diameters and compositions to suppress abnormal grain growth, enhance dielectric properties, and improve corrosion resistance, featuring a ratio of carbon between 1.0 and 4.0 weight percentage, magnesium between 0.01 and 1.0 weight percentage, and specific porosity levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fine SiC particles (0.05 μm or smaller) are used in high amounts (50-100 wt%) in the dielectric material, then the dielectric constant is improved and RF loss is reduced, but corrosion resistance deteriorates and surface unevenness occurs due to particle fall-off
Solution Approach 1:
The patent changes the particle size parameter of SiC from fine particles (0.05 μm or smaller) to coarse particles (0.5 μm or larger), which fundamentally alters the corrosion behavior and surface stability while maintaining the dielectric performance through optimized particle distribution and composition
Solution Approach 2:
The patent creates a composite material system combining Al2O3 matrix with coarse SiC particles and controlled impurity elements (Mg, Na, K), where the synergistic interaction between components provides both low dielectric loss and high corrosion resistance, overcoming the limitations of single-material systems
2Loss of energy
If fine SiC particles are highly dispersed in the dielectric material, then RF loss is reduced, but withstand voltage decreases and dielectric breakdown becomes more likely
Solution Approach 1:
The patent changes the particle size parameter from fine to coarse (D50 ≥ 0.5 μm), which increases the breakdown voltage while maintaining low dielectric loss through optimized particle morphology and distribution, eliminating the trade-off between these two parameters
3Ease of manufacture
If MgO is added as a sintering aid to promote sintering, then sinterability is improved, but abnormal grain growth of Al2O3 occurs and dielectric properties deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters by precisely controlling MgO content (0.01-1.0 wt%) and introducing Na2O and K2O, which modifies the sintering mechanism to achieve both easy sintering and abnormal grain growth suppression, thereby maintaining high dielectric constant
Solution Approach 2:
The patent creates a multi-component composite oxide system (Al2O3-SiC-MgO-Na2O-K2O) where the interaction between different oxide components provides synergistic effects: MgO promotes sintering while Na2O and K2O suppress abnormal grain growth, collectively achieving both manufacturability and dielectric performance
4Shape
If the particle diameter of Al2O3 and SiC is kept small, then dielectric constant is improved, but surface corrosion resistance deteriorates and particle desorption occurs during substrate adsorption
Solution Approach 1:
The patent changes the particle size parameter from small to large (SiC: D50 ≥ 0.5 μm, Al2O3: D50 ≥ 1.0 μm), which inherently improves particle stability and corrosion resistance while maintaining surface smoothness through optimized particle size distribution and dense sintering structure
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 composite sintered body achieves high relative dielectric constant, low dielectric loss tangent, and increased withstand voltage, preventing surface coarsening and particle desorption, thus ensuring reliable semiconductor substrate adsorption and processing.
Implementation Method 1
aluminum oxide, silicon carbide, and magnesium-aluminum composite oxide having a spinel-type crystal structure... to suppress abnormal grain growth
Implementation Method 2
by applying a direct-current voltage between the internal electrode and the semiconductor substrate, a portion of the main body between the internal electrode and the semiconductor substrate serves as a dielectric layer, and the semiconductor substrate is thereby adsorbed to the main body
Implementation Method 3
a composite sintered body... aluminum oxide, silicon carbide, and magnesium-aluminum composite oxide
Data Source
AI summary
A method of manufacturing a composite sintered body includes a step (Step S11) of molding mixed powder in which Al2O3, SiC, and MgO are mixed, into a green body having a predetermined shape and a step (Step S12) of generating a composite sintered body by sintering the green body. Then, in Step S11, the ratio of SiC to the mixed powder is not lower than 4.0 weight percentage and not higher than 13.0 weight percentage. Further, the purity of Al2O3 in Step S11 is not lower than 99.9%. It is thereby possible to suppress the abnormal grain growth of Al2O3 and suitably manufacture a composite sintered body having high relative dielectric constant and withstand voltage, and low tan δ.