Ceramic Substrate Holder Crystal Structure for Thermal Expansion Matching

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Solution Overview

Problem

Existing substrate processing apparatuses face issues with particle generation and substrate damage due to mismatched thermal expansion coefficients between the substrate and the substrate holding unit, leading to cracks and abrasion during high-temperature processes.

Innovation Solution

A substrate holding unit with a core body, electrode layer, and ceramic insulating layer featuring a mixed cubic and hexagonal crystal structure in the ceramic insulating layer, which matches the thermal expansion coefficient of the substrate, minimizing particle generation and substrate damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the substrate holding unit uses a single crystal structure (hexagonal), then the thermal expansion coefficient matches the substrate, but the stiffness is insufficient causing particle generation and substrate damage

Engineering Contradiction:

Improvethermal expansion matchingVSAvoidstiffness

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The ceramic insulating layer is constructed as a composite material containing both hexagonal crystal structures (for thermal expansion matching with the substrate) and cubic crystal structures (for providing stiffness and strength). This composite structure allows the holding unit to simultaneously achieve thermal compatibility and mechanical strength, preventing both particle generation from thermal mismatch and substrate damage from insufficient stiffness.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Different regions of the ceramic insulating layer have different crystal structures optimized for different functions: hexagonal crystal structures are distributed to provide thermal expansion matching, while cubic crystal structures are distributed to provide stiffness. This local differentiation of material properties within the same component enables simultaneous satisfaction of thermal and mechanical requirements.

Inventive Principle:

Principle #3Local quality

2Strength

If the substrate holding unit increases stiffness to prevent substrate damage, then substrate support improves, but thermal expansion mismatch causes cracks and particle generation

Engineering Contradiction:

ImprovestiffnessVSAvoidparticle generation and cracks

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The ceramic insulating layer uses a composite of hexagonal and cubic crystal structures where hexagonal phases provide thermal expansion compatibility with the substrate to prevent cracks and particle generation, while cubic phases provide the necessary stiffness for substrate support. This composite approach resolves the contradiction between strength and thermal compatibility.

Inventive Principle:

Principle #40Composite materials

3Strength

If the ceramic insulating layer is made entirely of cubic crystal structure, then stiffness increases, but thermal expansion coefficient mismatch occurs with the substrate

Engineering Contradiction:

ImprovestiffnessVSAvoidthermal expansion compatibility

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The ceramic insulating layer is designed as a composite material containing both cubic crystal structures (for stiffness) and hexagonal crystal structures (for thermal expansion compatibility). This composite structure allows the layer to achieve both mechanical strength and thermal compatibility, preventing the harmful effects of thermal mismatch while maintaining sufficient stiffness for substrate support.

Inventive Principle:

Principle #40Composite 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 effectively minimizes particle generation and substrate damage by aligning thermal expansion coefficients, extending the lifespan of the substrate and reducing scratches, while maintaining sufficient stiffness to support the substrate during high-temperature processes.

Implementation Method 1

a first surface of the ceramic insulating layer on the first surface of the core body includes a cubic crystal structure in at least a portion thereof, and includes a hexagonal crystal structure in at least another portion thereof

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

an electrode layer disposed on the core body and including pyrolytic graphite providing heat to the substrate

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS20250218844A1Substrate holding unit and substrate processing apparatus

Publication Date: 2025.07.03 SAMSUNG ELECTRONICS CO LTD

AI summary

According to an example embodiment of the present disclosure, provided is a substrate holding unit including: a core body having a first surface for supporting a substrate and a second surface opposite to the first surface; an electrode layer disposed on the first surface and the second surface of the core body; and a ceramic insulating layer covering the electrode layer and disposed on the first surface and the second surface of the core body, wherein a first surface of the ceramic insulating layer on the first surface of the core body includes a cubic crystal structure in at least a portion thereof, and includes a hexagonal crystal structure in at least another portion thereof.