Dry Ice Blasting for Plasma Chamber Cleaning

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Solution Overview

Problem

Off-line cleaning of plasma chambers is inefficient, requiring disassembly, lengthy preventative maintenance times, and high noise levels, while on-line methods lack effective solutions for removing carbon and fluorine-based polymer deposits from interior surfaces without damaging the surfaces or using hazardous solvents.

Innovation Solution

An on-line method using dry ice blasting with a system that accelerates CO2 pellets to high velocity, removing contaminants from plasma chamber surfaces without damaging them, utilizing a low-pressure and low-flow rate dry ice blasting system that is noise-free and non-abrasive, specifically designed for use in cleanroom environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If off-line cleaning is used to remove polymer deposits from plasma chamber surfaces, then contaminants can be removed, but the cleaning process requires disassembly, takes lengthy preventative maintenance times (greater than 24 hours), and involves high noise levels

Engineering Contradiction:

Improvecontaminant removal effectivenessVSAvoidpreventative maintenance time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces traditional mechanical cleaning methods (scrapers, brushes, solvents) with dry ice blasting technology. The dry ice pellets are accelerated through a nozzle and impact the polymer deposits, using kinetic energy and sublimation to remove contaminants without mechanical contact or chemical solvents, thereby reducing maintenance time while maintaining cleaning effectiveness

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the phase transition of dry ice (solid CO2) to gas during the blasting process. When dry ice pellets impact the polymer deposits and chamber surfaces, they rapidly sublime from solid to gas state, absorbing heat and creating a cleaning effect that removes contaminants without leaving residue or requiring lengthy drying times

Inventive Principle:

Principle #36Phase transitions

2Reliability

If high CDA pressure and high CDA flow rate are used in dry ice blasting, then cleaning effectiveness improves, but noise levels increase and surface damage risk increases

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidsurface damage and noise

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the CDA pressure and flow rate parameters to achieve effective cleaning at lower levels. By adjusting these parameters within specific ranges (e.g., CDA pressure of 5-50 psi, flow rate of 5-20 CFM), the system achieves sufficient cleaning effectiveness while minimizing noise generation and preventing surface damage from excessive impact force

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses dry ice pellets as an intermediary medium between the CDA system and the chamber surfaces. The dry ice pellets absorb the kinetic energy of the compressed air, converting it into a controlled cleaning action that is less damaging to surfaces while maintaining cleaning effectiveness, and also act as a noise-dampening intermediary

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If traditional cleaning methods are used, then contaminants can be removed, but hazardous solvents are required and surface integrity may be compromised

Engineering Contradiction:

Improvecontaminant removalVSAvoidhazardous solvent use and surface damage

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent employs disposable dry ice pellets as the cleaning medium. These pellets are inexpensive, readily available, and single-use - they are launched at the contaminants and then sublimated away, leaving no residue or need for solvent disposal. This eliminates hazardous solvent handling while maintaining effective contaminant removal

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent converts the potentially harmful high-velocity impact of compressed air into a beneficial cleaning mechanism by using dry ice pellets as the medium. The kinetic energy that would otherwise damage surfaces is instead used to fracture and remove polymer deposits, while the sublimation process provides a gentle, non-abrasive cleaning action

Inventive Principle:

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

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 method significantly reduces Mean Time To Clean (MTTC) to 48 hours or less, ensures surface integrity, and avoids hazardous solvent use, effectively removing contaminants without redeposition, thus improving operational efficiency and safety.

Implementation Method 1

Carbon dioxide (CO2) 'dry ice' pellet technology uses compressed air to accelerate frozen 'dry ice' pellets to a high velocity

Methodology Applied

Scientific EffectCompressed air acceleration: Pressure Gradient

Implementation Method 2

Upon impact, the dry ice pellets sublimate to a harmless gaseous state (vaporize)

Methodology Applied

Scientific EffectSublimation: Sublimation

Data Source

PatentUS8292698B1On-line chamber cleaning using dry ice blasting

Publication Date: 2012.10.23 LAM RES CORP

AI summary

An on-line method of cleaning contaminants from at least one interior surface in plasma chambers comprises blasting one or more interior surfaces of a plasma chamber with dry ice to remove contaminants from the one or more surfaces.