Glass Substrate Cleaning via Sequential Si Elution Liquids

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Solution Overview

Problem

Conventional methods for cleaning glass substrates after polishing are complex and reduce productivity, as they often require multiple cleaning steps or specialized equipment, and can leave residual abrasive or foreign matter, leading to pinholes and degraded magnetic recording characteristics.

Innovation Solution

Using two or more cleaning liquids with different Si element elution abilities, where the highest elution is used first to loosen abrasive and foreign matter, followed by scrubbing for removal, and the lowest elution is used last to stabilize the surface, simplifying the cleaning process and avoiding excessive cleaning effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If polishing is performed to remove projections and foreign matter, then surface smoothness is improved, but abrasive firmly adheres to the substrate making removal difficult

Engineering Contradiction:

Improvesurface smoothnessVSAvoidease of abrasive removal

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The cleaning process is segmented into multiple sequential steps using different cleaning liquids with varying Si element elution abilities. The first cleaning liquid (high elution) loosens abrasive, the second (medium elution) removes it, and the third (low elution) stabilizes the surface, making each step more effective than a single-step process.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter of Si element elution ability across different cleaning liquids. By selecting cleaning liquids with progressively decreasing Si element elution abilities, the process optimizes both abrasive removal effectiveness and surface stability, resolving the contradiction between thorough cleaning and surface integrity.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If multiple cleaning steps are used to remove abrasive, then cleaning effectiveness is improved, but process complexity increases and productivity decreases

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidproductivity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Multiple cleaning functions (loosening, removing, and stabilizing) are merged into a single integrated cleaning process using sequentially applied cleaning liquids. This combines the effectiveness of multiple traditional cleaning steps into one streamlined operation, maintaining high cleaning effectiveness while improving productivity.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If strong cleaning action is used to remove all abrasive, then cleaning effectiveness is improved, but surface roughness degrades

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidsurface roughness

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Different cleaning liquids with specific Si element elution abilities are applied in sequence, with each liquid having a localized function: the first targets abrasive loosening, the second targets abrasive removal, and the third targets surface stabilization. This localized approach ensures thorough cleaning while preserving surface quality.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The first cleaning liquid with high Si element elution ability performs a preliminary action of loosening abrasive from the substrate surface before the second cleaning liquid removes it. This preliminary loosening action reduces the force needed in subsequent steps, preventing surface damage while ensuring complete abrasive removal.

Inventive Principle:

Principle #10Preliminary action

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 effectively removes abrasive and foreign matter without degrading surface roughness, reduces residual cleaning liquid issues, and increases the recording capacity of magnetic disks by maintaining a smooth and clean substrate surface.

Implementation Method 1

using two or more types of cleaning liquid having different Si element eluting abilities, with the one having the highest Si element elution used first

Methodology Applied

Scientific EffectSi element elution: Solvation

Implementation Method 2

cleaning by scrubbing

Methodology Applied

Scientific EffectMechanical friction: Friction

Data Source

PatentUS8113017B2Method for cleaning a glass substrate, method for fabricating a glass substrate, and magnetic disk using same

Publication Date: 2012.02.14 HOYA CORPORATION

AI summary

A method for cleaning a glass substrate which ensures removal of abrasive and other foreign matter without making a cleaning step complicated involves cleaning the glass substrate by scrubbing using two or more types of cleaning liquid having different Si element elution abilities. The cleaning liquid having the highest Si element elution is used first, and the cleaning liquid having the lowest Si element elution is used last.