Anionic Polyvinyl Acetal Sponge for Wafer Cleaning
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Solution Overview
Problem
Existing cleaning methods for electronic components, such as semiconductor wafers and hard disks, face challenges in efficiently removing microscopic particles while minimizing surface damage during scrub cleaning.
Innovation Solution
A cleaning sponge made of polyvinyl acetal porous resin material with anionic or cationic functional groups is used, which provides elasticity and enhanced zeta potential characteristics, allowing for improved repulsive forces and adsorptivity when used with specific cleaning liquids and abrasive grains, reducing the need for excessive brushing and minimizing surface damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sponge roller is firmly pressed against the surface to be cleaned, then cleaning efficiency is improved, but physical damage to the surface increases
Solution Approach 1:
The invention changes the chemical parameter of the sponge material by introducing anionic functional groups (such as carboxyl, sulfo, sulfate, or phosphate groups). This chemical modification alters the zeta potential characteristics of the sponge, enabling it to generate electrical repulsive forces against abrasive grains. As a result, the sponge can achieve effective cleaning with reduced mechanical pressing force, thereby improving cleaning efficiency while minimizing physical damage to the surface.
Solution Approach 2:
The invention replaces part of the mechanical cleaning action with electrical forces. By endowing the sponge material with anionic functional groups, the system utilizes electrical repulsive forces between the sponge and abrasive grains to enhance cleaning effectiveness. This substitution reduces the reliance on mechanical pressing force, allowing for gentler cleaning that prevents surface damage while maintaining high cleaning efficiency.
2Productivity
If conventional polyvinyl acetal porous material is used, then the sponge is elastic and can be pressed firmly, but cleaning efficiency is insufficient and excessive brushing is required
Solution Approach 1:
The invention modifies the chemical composition of the polyvinyl acetal porous material by incorporating anionic functional groups. This parameter change transforms the sponge's interaction with abrasive grains from purely mechanical to electrochemical, where the anionic groups generate electrical repulsive forces. Consequently, the sponge achieves superior cleaning efficiency with reduced brushing intensity, as the electrical forces assist in separating and removing particles without requiring excessive mechanical action.
Solution Approach 2:
The invention creates a composite material system by combining polyvinyl acetal porous material with anionic functional groups. This composite structure integrates the elastic properties of the original material with the electrical repulsive capabilities of the anionic groups. The resulting composite sponge exhibits both mechanical flexibility for gentle contact and electrical activity for enhanced particle removal, eliminating the need for excessive brushing while improving cleaning efficiency.
3Force
If zeta potential of the sponge is increased, then repulsive force against abrasive grains increases, but manufacturing complexity increases
Solution Approach 1:
The invention achieves increased zeta potential through a straightforward chemical modification: introducing anionic functional groups into the polyvinyl acetal porous material. This parameter change can be accomplished during the material synthesis process by selecting appropriate monomers or additives containing these functional groups. The approach directly increases the electrical repulsive force against abrasive grains without requiring complex multi-step manufacturing processes, thus achieving high zeta potential with relatively simple material composition and fabrication.
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 sponge improves cleaning efficiency and reduces surface damage by leveraging zeta potential differences to enhance repulsive forces and adsorptivity, leading to more effective particle removal without excessive physical contact.
Implementation Method 1
the sponge includes an anionic functional group... zeta potential of the polyvinyl acetal porous resin material may be −30 mV or less (absolute value of 30 or greater)... an electrical repulsion force acts between the grains and the sponge roller if the zeta potential of the cleaning sponge and the zeta potential of the respective grains are homopolar
Implementation Method 2
an electrical repulsion force acts between the grains and the sponge roller if the zeta potential of the cleaning sponge and the zeta potential of the respective grains are homopolar (either both positive or negative), and electrical adsorptivity acts if they are heteropolar
Implementation Method 3
a cleaning sponge according to a first aspect of the present invention is made of a polyvinyl acetal porous resin material having elasticity in a wet state
Data Source
AI summary
A sponge roller is made of a polyvinyl acetal porous resin material having elasticity in a wet state, includes a roller in an approximate cylinder form and a plurality of protrusions formed integrally on an outer peripheral surface of the roller, and rotates the multiple protrusions to make contact with a surface to be cleaned so as to clean the surface. The polyvinyl acetal porous resin material constituting the sponge roller contains a cationic functional group.