Composite Dielectric Material for Electrostatic Chucking
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Solution Overview
Problem
Existing electrostatic chucking devices face issues with uneven dielectric loss variations leading to temperature differences on the wafer surface, low withstand voltage, and high costs due to the use of rare earth oxides like yttrium oxide, and insufficient adsorption force with low dielectric constants in insulating materials like aluminum nitride.
Innovation Solution
A composite sintered body with conductive particles dispersed in an insulating material, optimizing dielectric constant, dielectric loss, and volume resistivity to achieve balanced electrostatic adsorption force, desorption response, and high withstand voltage, while minimizing temperature differences and reducing material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If yttrium oxide sintered body with silicon nitride is used to increase dielectric constant and adsorption force, then electrostatic adsorption force is improved, but dielectric loss varies unevenly causing temperature differences on wafer surface
Solution Approach 1:
The patent changes the material composition parameters by replacing yttrium oxide with aluminum oxide and aluminum nitride, and controls the dielectric loss parameter to be 0.005 or less, achieving uniform temperature distribution while maintaining adequate adsorption force
Solution Approach 2:
The patent uses composite materials consisting of aluminum oxide and aluminum nitride in specific ratios (aluminum nitride content: 10-90 mass%) to achieve both adequate dielectric constant for adsorption force and low dielectric loss for temperature uniformity
2Temperature
If aluminum nitride sintered body is used to improve temperature uniformity, then dielectric loss is reduced, but dielectric constant is low resulting in insufficient adsorption force
Solution Approach 1:
The patent creates a composite material system combining aluminum oxide (higher dielectric constant) and aluminum nitride (lower dielectric loss) to achieve a balance where the composite has both adequate dielectric constant for adsorption and low dielectric loss for temperature uniformity
Solution Approach 2:
The patent optimizes the compositional ratio parameter of aluminum nitride (10-90 mass%) to achieve the optimal balance between dielectric constant and dielectric loss, ensuring both adsorption force and temperature uniformity requirements are met
3Force
If high dielectric constant material is used to increase adsorption force, then electrostatic adsorption force is improved, but material cost increases due to rare earth oxides
Solution Approach 1:
The patent replaces expensive rare earth oxide (yttrium oxide) with cheaper common oxides (aluminum oxide and aluminum nitride), achieving the same functional effect at lower material cost
Solution Approach 2:
The patent changes the material composition from rare earth-based to common metal oxide/nitride-based materials, maintaining the required dielectric constant through compositional optimization rather than relying on expensive materials
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 reliable dielectric material with improved electrostatic adsorption force, desorption response, and withstand voltage, ensuring uniform temperature distribution and increased product reliability, while being cost-effective.
Implementation Method 1
By applying a direct current voltage between the dielectric plate and the wafer placed on the dielectric plate, an electrostatic adsorption force is generated due to the Coulomb force or a small leakage current
Implementation Method 2
a variation in dielectric loss occurs in a sintered body, an amount of heat generation by a high frequency varies in a surface of the sintered body
Data Source
AI summary
A dielectric material includes a composite sintered body in which conductive particles are dispersed in an insulating material, in which a dielectric constant at a frequency of 40 Hz is 10 or higher, and a difference between a maximum dielectric loss value and a minimum dielectric loss value at a frequency of 1 MHz in a surface of the composite sintered body is 0.002 or less.