Electrostatic Adhesive Sheet Cleaning for Curved Vacuum Surfaces

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Solution Overview

Problem

Existing cleaning methods for vacuum processing apparatuses fail to effectively remove particles from curved surfaces and fine roughness on insulating bodies coated on metal components, leading to contamination and defective semiconductor devices during plasma processing.

Innovation Solution

A cleaning apparatus with an adhesive sheet and conductive sheet, where the conductive sheet is applied with positive or negative voltage and pressed onto the surface using a pressing member with a controlled force, ensuring close adherence and effective removal of particles from curved and fine surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ultrasonic waves are used for cleaning, then cleaning capability is improved, but particles attached to fine surface roughness on insulating bodies cannot be removed

Engineering Contradiction:

Improvecleaning capabilityVSAvoidparticle removal effectiveness

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical ultrasonic cleaning system with an electrostatic cleaning system. A conductive sheet is pressed against the insulating body surface, and voltage is applied to generate electrostatic attraction forces that draw particles off the surface, including from fine roughness areas where ultrasonic waves fail to reach.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the cleaning mechanism from mechanical vibration (ultrasonic) to electrical field interaction (electrostatic). By applying voltage to the conductive sheet, the system creates electrostatic forces that can access and remove particles from surface roughness that mechanical methods cannot reach.

Inventive Principle:

Principle #35Parameter changes

2Area of stationary object

If cleaning fluid or dry ice is injected, then cleaning coverage is improved, but particles on fine roughness surfaces cannot be removed

Engineering Contradiction:

Improvecleaning coverageVSAvoidparticle removal from roughness

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent replaces fluid injection and dry ice methods with direct contact electrostatic cleaning. The conductive sheet pressed against the surface allows electrostatic forces to act directly on particles, enabling removal from fine roughness areas that fluid methods cannot access.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If a cleaning sheet is adhered to a flat wafer, then cleaning of flat surfaces is improved, but cleaning of curved surfaces and fine roughness is not achieved

Engineering Contradiction:

Improvecleaning effectiveness on flat surfacesVSAvoidapplicability to curved and rough surfaces

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent uses a flexible conductive sheet that can conform to curved surfaces and fine roughness. Unlike rigid flat cleaning sheets, this flexible sheet makes intimate contact with complex geometries, allowing electrostatic cleaning to work effectively on curved and irregular surfaces.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes from adhesive-based cleaning sheet attachment to electrostatic-based cleaning. The conductive sheet is held in place by pressing force and maintains contact through flexibility, while voltage application creates electrostatic forces that remove particles even from surfaces where adhesive contact alone would be insufficient.

Inventive Principle:

Principle #35Parameter changes

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 enables thorough cleaning of particles from curved and fine surfaces, preventing contamination and reducing defects in semiconductor devices by ensuring electrostatic attraction and removal of particles from insulating bodies coated on metal components.

Implementation Method 1

applying positive or negative voltage to the conductive sheet... electrostatic attraction and removal of particles from insulating bodies

Methodology Applied

Scientific EffectElectrostatic attraction: Electrostatics

Implementation Method 2

an adhesive sheet... pressing the adhesive sheet onto a curved surface... closely adhere the adhesive surface

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS8024831B2Cleaning method

Publication Date: 2011.09.27 HITACHI HIGH TECH CORP

AI summary

A cleaning method using a cleaning apparatus having an adhesive sheet, a conductive sheet in contact with a base material of the adhesive sheet, and a pressing member for pressing the conductive sheet onto the adhesive sheet. The pressing member includes a voltage applier, and a pressing force controller which presses the adhesive sheet onto a curved surface of a portion to be cleaned of a vacuum processing apparatus from above the conductive sheet. The method includes pressing the pressing member by a pressing force controlled via the pressing force controller to press the conductive sheet and the adhesive sheet to adhere an adhesive surface of the adhesive sheet to the curved surface of the portion to be cleaned, and applying a voltage to the conductive sheet or applying a voltage having a temporally changed polarity.