Upper Electrode Cooling Layout to Prevent Plasma Chamber Condensation

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Solution Overview

Problem

In plasma processing apparatuses, condensation occurs near the upper electrode due to low-temperature coolant usage, potentially damaging electric components and disrupting high-frequency power distribution, leading to uneven plasma processing.

Innovation Solution

The apparatus employs a low-dew point gas to maintain a positive pressure within the antenna chamber, suppressing condensation and using a heat-insulating member with electromagnetic shielding properties to reduce heat transfer and power leakage between the cover member and pipeline.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a low-temperature coolant is used to cool the upper electrode, then the cooling effect is improved, but condensation occurs near the upper electrode

Engineering Contradiction:

Improvecoolant temperatureVSAvoidcondensation

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

A heat-insulating member is introduced as an intermediary between the coolant pipeline and the upper electrode structure. This mediator reduces heat transfer from the electrode to the pipeline, preventing the pipeline surface temperature from dropping below the dew point and thus eliminating condensation while maintaining effective electrode cooling

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful condensation phenomenon into a beneficial indicator by using a heat-insulating member that prevents heat loss to the coolant pipeline. This insulation layer that was originally intended to prevent heat transfer to the electrode is repurposed to prevent heat transfer from the electrode, thereby preventing condensation without compromising cooling efficiency

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Temperature

If the upper electrode is cooled to prevent overheating, then thermal management is improved, but high-frequency power distribution becomes uneven

Engineering Contradiction:

Improveupper electrode temperatureVSAvoidplasma processing uniformity

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The upper electrode cooling system is segmented into distinct thermal zones. The heat-insulating member is selectively positioned to isolate only the portions of the electrode structure that would otherwise cause condensation or excessive heat loss, while allowing other portions to maintain optimal temperatures for uniform plasma generation and high-frequency power distribution

Inventive Principle:

Principle #1Segmentation

3Reliability

If a cover member is added to protect electric components, then component protection is improved, but heat transfer and electromagnetic power leakage occur between the cover member and pipeline

Engineering Contradiction:

Improveelectric component integrityVSAvoidheat transfer and power leakage

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The cover member is constructed as a composite structure combining electromagnetic shielding material with heat-insulating material. This composite design simultaneously provides protection for electric components while minimizing both electromagnetic power leakage and heat transfer to the coolant pipeline, preventing condensation without compromising component safety

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

This solution effectively prevents condensation and maintains the integrity of electric components, ensuring consistent high-frequency power distribution and improved plasma processing uniformity.

Implementation Method 1

The cooler is provided within the cover member and is configured to cool the upper electrode with a coolant having a temperature lower than a dew point temperature of exterior air outside the processing vessel

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

The gas supply is configured to supply a low-dew point gas having a dew point temperature lower than the dew point temperature of the exterior air into a space surrounded by the cover member and the upper electrode

Methodology Applied

Scientific EffectCondensation suppression: Condensation

Implementation Method 3

The plasma processor is configured to form a gas within the processing vessel into plasma by supplying a high frequency power to at least one of the placing table or the upper electrode

Methodology Applied

Scientific EffectPlasma generation: Plasma

Data Source

PatentUS11862436B2Plasma processing apparatus and plasma processing method

Publication Date: 2024.01.02 TOKYO ELECTRON LTD

AI summary

A plasma processing apparatus includes a processing vessel; a placing table, serving as a lower electrode, disposed within the processing vessel; an upper electrode serving as a facing electrode of the placing table; a plasma processor configured to form a gas within the processing vessel into plasma by supplying a high frequency power and to process a processing target object on the placing table with the plasma; a cover member configured to cover the upper electrode from thereabove; a cooler provided within the cover member and configured to cool the upper electrode with a coolant having a temperature lower than a dew point temperature of exterior air outside the processing vessel; and a gas supply configured to supply a low-dew point gas having a dew point temperature lower than the dew point temperature of the exterior air into a space surrounded by the cover member and the upper electrode.