Boron Carbide Focus Ring Residual Stress Control

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Solution Overview

Problem

Existing plasma processing apparatuses face issues with nonuniform plasma distribution due to high electric power usage, leading to degraded quality of minute semiconductor elements and increased plasma processing irregularities, particularly in focus rings with uneven residual stress distribution.

Innovation Solution

A manufacturing method for ceramic components, specifically focus rings, utilizing boron carbide with controlled residual stresses between -600 to +600 MPa, achieved through a process involving granulation, sintering, and thermal treatment to ensure even stress distribution and improved shaping machinability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If high electric power is used in plasma processing, then processing capability is improved, but plasma distribution uniformity deteriorates due to wavelength effects and skin effects

Engineering Contradiction:
Improveelectric powerVSAvoidplasma distribution uniformity
Core Design Contradiction:
PowerVSManufacturing precision

Solution Approach 1:

The focus ring is designed with non-uniform thickness to create different plasma impedance characteristics at different radial positions. The thickness varies from the center to the edge, allowing localized adjustment of plasma distribution to compensate for wavelength and skin effects, thereby maintaining uniformity while using high electric power

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the physical parameter of the focus ring (thickness distribution) to alter plasma impedance characteristics. By adjusting the thickness parameter radially, the plasma distribution uniformity is improved while maintaining high electric power processing capability

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional ceramic materials are used for focus rings, then material availability is improved, but residual stress uniformity deteriorates leading to poor machining success rate

Engineering Contradiction:
Improvematerial availabilityVSAvoidresidual stress uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent uses boron carbide ceramic material which provides both material availability and improved residual stress uniformity. The specific ceramic composition is selected to achieve uniform residual stress distribution while maintaining manufacturability

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

A heat treatment process is applied before shaping machining to pre-adjust the residual stress distribution in the focus ring. This preliminary heat treatment ensures uniform residual stress, thereby improving the machining success rate and reducing breakage during subsequent processing

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If focus rings with uneven residual stress are used, then manufacturing simplicity is improved, but shaping machining success rate deteriorates due to breakage

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidshaping machining success rate
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Heat treatment is performed as a preliminary step before shaping machining to uniformize residual stress distribution. This preliminary action prevents breakage during machining by eliminating stress concentration, thereby improving machining success rate without significantly complicating the manufacturing process

Inventive Principle:
Principle #10Preliminary action

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 method enhances the quality and stability of ceramic components, ensuring uniform plasma distribution and improved etching resistance, impact resistance, and high success rates in shaping machining, thereby improving the manufacturing efficiency of semiconductor elements.

Implementation Method 1

shaping machining after thermal treatment of the material

Methodology Applied
Scientific EffectThermal treatment: Heat Treatment

Implementation Method 2

residual stresses measured on a surface of two spots with different distances from a center may be S1 and S2, respectively, and wherein a difference between S1 and S2 may be -600 to +600 MPa

Methodology Applied
Scientific EffectStress relaxation: Stress Relaxation

Implementation Method 3

a manufacturing method of a ceramic component, a manufacturing method of a focus ring

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP4082992B1Focus ring and method for manufacturing a focus ring
Publication Date: 2025.04.02 SOLMICS CO LTD
  • EP4082992B1 patent drawingFigure 1
  • EP4082992B1 patent drawingFigure 2

AI summary

The present disclosure relates to a ceramic component and a manufacturing method of a ceramic component, and provides a ceramic component comprising boron carbide, wherein residual stress values measured at surface of two spots with different distances from a center are respectively S1 and S2, and a difference between the S1 and S2 is -600 to +600 MP. According to the present disclosure, it is possible to manufacture a ceramic component improved in the quality and simultaneously efficiently used in apparatus for manufacturing a semiconductor element.