Electrostatic Chuck Composite Oxide Sintered Body
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Solution Overview
Problem
Conventional electrostatic chucks face issues with wafer damage due to high voltage requirements and reduced voltage resistance when using materials with high volume resistivity, and are prone to breakage during processing, especially in halogen-based corrosive gas environments.
Innovation Solution
An electrostatic chuck with a yttrium aluminum composite oxide sintered body or a composite oxide sintered body containing aluminum and a rare earth element, excluding yttrium, is developed, featuring a specific L* value range for the reflected color tone and oxygen deficiencies, which allows for high clamping force at low voltage and increased thickness, and is integrated into an electrostatic chuck device with a tabular body, internal electrode, and temperature control base member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a voltage of higher than 2 kV is used to adsorb and fix wafers when using materials with high volume resistivity, then the wafer can be held securely, but the wafer becomes charged with electricity and is liable to be damaged
Solution Approach 1:
The patent changes the electrical parameter (volume resistivity) of the electrostatic chuck material from high (>1.0×10^14 Ω·cm) to low (1.0×10^12 to 1.0×10^13 Ω·cm), enabling secure wafer holding at low voltage (1 to 3 kV) without excessive charge accumulation that damages wafers
2Force
If the thickness of the electrostatic chuck material is reduced to less than 0.3 mm to increase clamping force, then the clamping force increases, but the voltage resistance is reduced making it impossible to apply sufficiently high voltage and the electrostatic chuck breaks during processing
Solution Approach 1:
The patent optimizes the thickness parameter of the electrostatic chuck material to a specific range (0.3 to 1.0 mm), which balances mechanical strength for voltage resistance with sufficient thinness to provide high clamping force, preventing both breakage and ensuring effective operation
3Ease of operation
If conventional materials are used in halogen base corrosive gas environments, then the electrostatic chuck can operate, but corrosion damages the constitutional members
Solution Approach 1:
The patent employs composite oxide materials (such as alumina, magnesia, zirconia, or silica combined with other oxides) for the electrostatic chuck, providing both the necessary electrical properties for operation and superior corrosion resistance against halogen base corrosive gases and plasma
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 provides a high clamping force in halogen-based corrosive gases and plasmas, enabling operation at low voltage with increased thickness of the insulating dielectric material, enhancing both clamping force and plasma resistance.
Implementation Method 1
an electrostatic chuck system in which a semiconductor wafer is adsorbed by virtue of an electrostatic attracting force (coulomb force)
Implementation Method 2
the halides produced work as a protective film on the surface to inhibit vaporization of yttrium and aluminum and reaction thereof with halogens
Data Source
AI summary
The present invention relates to an electrostatic chuck comprising a specific composite oxide sintered body, wherein in the sintered body, an L* value of a reflected color tone measured by a C light source on a 2° angle visual field condition is 10 or more and 50 or less in a CIEL*a*b* color system prescribed in JIS Z 8729-1994 and an electrostatic chuck device comprising an electrostatic chuck member (A) having a tabular body provided with a clamping surface for clamping a sample by the electrostatic force, an internal electrode layer for clamping a sample by electrostatic force which is provided on the back face of the tabular body and an insulation layer, wherein at least the sample clamping surface of the tabular body in the electrostatic chuck member (A) comprises the composite oxide sintered body constituting the electrostatic chuck described above.