Electrostatic Chuck Low Mn Ceramic Suppresses Residual Adsorption

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Solution Overview

Problem

In film forming devices, the residual adsorption force in electrostatic chucks increases over time, making it difficult to remove wafers without causing deformation or breakage.

Innovation Solution

An electrostatic chuck with a ceramic base body and adsorption electrode where the Mn content is 1×10−4% by mass or less from the upper surface to the adsorption electrode, reducing the generation of positive holes and leakage current, thereby suppressing residual adsorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional electrostatic chuck with ceramic base body is used for repeated film formation processing, then the electrostatic adsorption function is maintained, but the residual adsorption force gradually increases making wafer removal difficult

Engineering Contradiction:

Improveelectrostatic adsorption functionVSAvoidwafer removal ease

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the chemical composition parameter of the ceramic base body by strictly controlling the Mn content to be 1×10^-4% by mass or less. This parameter change prevents the generation of fixed charges (holes) in the ceramic during plasma treatment, thereby suppressing the increase in residual adsorption force over repeated processing cycles while maintaining electrostatic adsorption functionality.

Inventive Principle:

Principle #35Parameter changes

2Force

If high residual adsorption force is present during wafer removal with lift pin, then the wafer can be held firmly during processing, but the wafer is deformed or broken during removal

Engineering Contradiction:

Improveadsorption forceVSAvoidwafer integrity

Core Design Contradiction:

ForceVSStrength

Solution Approach 1:

By changing the Mn content parameter of the ceramic base body to 1×10^-4% by mass or less, the patent suppresses the generation of fixed charges that cause residual adsorption. This reduces the adsorption force remaining after DC voltage cancellation, enabling wafer removal without deformation or breakage while maintaining firm holding during processing.

Inventive Principle:

Principle #35Parameter changes

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

This design allows for easy removal of wafers by minimizing residual adsorption force, preventing deformation or breakage and ensuring stable processing.

Implementation Method 1

Coulomb force generated by dielectric polarization

Methodology Applied

Scientific EffectDielectric polarization: Polarisation

Implementation Method 2

electrostatic adsorption force, such as Coulomb force generated by dielectric polarization and Johnson-Rahbek force generated by a slight leakage current

Methodology Applied

Scientific EffectElectrostatic adsorption: Electrostatic Induction

Implementation Method 3

Johnson-Rahbek force generated by a slight leakage current

Methodology Applied

Scientific EffectJohnson-Rahbek force:

Implementation Method 4

when electrons are injected from plasma into the subject to be processed, fixed charges (holes) are generated in the ceramic base body

Methodology Applied

Scientific EffectPlasma electron injection: Plasma

Implementation Method 5

fixed charges (holes) are generated in the ceramic base body, and then the fixed charges (holes) remain in the ceramic base body even after the DC voltage application is canceled

Methodology Applied

Scientific EffectFixed charge generation:

Data Source

PatentUS9543184B2Electrostatic chuck

Publication Date: 2017.01.10 KYOCERA CORP

AI summary

The present invention is an electrostatic chuck including a ceramic base body and an adsorption electrode provided inside of or on the lower surface of the ceramic base body and having a portion where a Mn content is 1×10−4% by mass or less in a region from the upper surface of the ceramic base body to the adsorption electrode.