Electrostatic Chuck Compressive Attachment for Thermal Stress

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Solution Overview

Problem

Conventional electrostatic chucks face issues with adhesive bond degradation due to stress from thermal expansion differences and plasma erosion, leading to helium and vacuum leakage, which shortens their lifespan.

Innovation Solution

Incorporating a compressive attachment portion at the outer edge of the electrostatic chuck, formed by deforming a metal member between the ceramic plate and the heat insulating layer, to securely attach the second layer to both the ceramic plate and the first layer, reducing the formation of gaps and enhancing the chuck's resistance to plasma damage and thermal expansion stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a heat conductive adhesive bond is used to attach the heat-uniformizing plate to the mount plate, then thermal conductivity is improved, but the adhesive bond degrades due to stress from thermal expansion differences and plasma erosion

Engineering Contradiction:

Improvethermal conductivityVSAvoidadhesive bond durability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent introduces an adhesive bond protecting layer as an intermediary component between the heat conductive adhesive bond and the external environment. This protecting layer specifically shields the adhesive bond from plasma erosion while allowing thermal conduction to pass through, thereby resolving the contradiction between maintaining thermal conductivity and protecting against plasma-induced degradation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The adhesive bond protecting layer is applied in advance to cover and protect the heat conductive adhesive bond before plasma exposure occurs. This preemptive protection cushions the adhesive bond against plasma erosion and thermal expansion stress, preventing degradation before it occurs and extending the operational life of the electrostatic chuck.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If the adhesive bond protecting layer is provided to protect against plasma erosion, then reliability is improved, but the layer itself degrades over time leading to gas leakage

Engineering Contradiction:

Improveprotection against plasma erosionVSAvoidservice life of protecting layer

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent employs composite material structure where the adhesive bond protecting layer is made from materials with specific properties that resist plasma erosion while maintaining structural integrity. The protecting layer is formulated as a composite that combines erosion resistance with long-term stability, preventing both plasma damage and premature degradation that would lead to gas leakage.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If the mount plate and heat-uniformizing plate are bonded with adhesive, then assembly is simplified, but stress from linear expansion coefficient difference causes adhesive degradation

Engineering Contradiction:

Improveassembly simplicityVSAvoidadhesive bond strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The adhesive bond protecting layer serves as a mediator that isolates the adhesive bond from the harsh plasma environment and thermal cycling stresses. By providing this protective barrier, the adhesive bond can maintain its bonding strength despite the inherent stress from linear expansion coefficient differences between the ceramic mount plate and aluminum heat-uniformizing plate.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution effectively suppresses gas leakage and extends the electrostatic chuck's lifespan by preventing adhesive bond degradation and improving thermal conductivity, while also enhancing corrosion and wear resistance through surface processing.

Implementation Method 1

The first layer includes a heater. The heater supplies heat to the work via the mount plate.

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The second layer transmits heat from the heater to the mount plate.

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

The compressive attachment portion is formed by deforming a metal member between the ceramic plate and the heat insulating layer

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Data Source

PatentUS9370920B2Electrostatic chuck, mount plate support, and manufacturing method of electrostatic chuck

Publication Date: 2016.06.21 KIOXIA CORP

AI summary

According to one embodiment, an electrostatic chuck comprises a mount plate, a first layer, and a second layer. The first layer includes a heater. The second layer is provided between the mount plate and the first layer. The second layer transmits heat from the heater to the mount plate. The second layer includes a compressive attachment portion. The compressive attachment portion is formed at the outer edge. The face on the mount plate side of the compressive attachment portion is compressed and attached to the mount plate. The face on the first layer side of the compressive attachment portion is compressed and attached to the first layer.