BTA Solubility in Ionic Surfactant CMP Slurry

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Solution Overview

Problem

Current chemical mechanical polishing (CMP) slurries using 1H-benzotriazole (BTA) face challenges with solid foreign materials causing scratching and require excessive solvent volumes for filtration, which is costly, messy, and inefficient, and using alternative solvents like methanol or ethanol poses safety hazards.

Innovation Solution

Dissolving BTA in an ionic surfactant solution, such as sodium alkyl sulfate, and optionally a polyelectrolyte like polyacrylic acid, allows for effective filtration and stabilization, reducing particle scratches and safety risks while minimizing solvent volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If BTA is dissolved in water, then it is compatible with copper CMP slurry medium, but BTA is poorly soluble requiring excessive solvent volume for filtration

Engineering Contradiction:
Improvecompatibility with copper CMP slurry mediumVSAvoidsolvent volume required
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent changes the solvent parameter from water to a mixture containing water-miscible organic solvents (methanol, ethanol, isopropanol) in specific proportions (5-50% by weight). This parameter change increases BTA solubility from poor (in pure water) to high (in the mixed solvent system), reducing the total solvent volume required while maintaining compatibility with the copper CMP slurry medium.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If BTA is dissolved in organic solvents like methanol or ethanol, then solubility is high, but flash point safety problems occur

Engineering Contradiction:
ImproveBTA solubilityVSAvoidflash point safety hazard
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the solvent composition parameter by using a mixed solvent system where water-miscible organic solvents (flash point safety hazards) are combined with water in specific ratios (5-50% organic content). This parameter change maintains high BTA solubility while reducing the overall flammability risk compared to using pure organic solvents, as the water content suppresses the flash point hazard.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite solvent system combining water and water-miscible organic solvents in specific proportions. This composite approach leverages the high solubility capability of organic solvents while using water as a diluent to reduce flammability, achieving a balance between solubility performance and safety characteristics.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If BTA is dissolved in water, then no removal is needed, but excessive volume requires costly and time-consuming filtration

Engineering Contradiction:
Improvesimplicity of slurry preparationVSAvoidfiltration time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent changes the solvent parameter from pure water to a water-organic solvent mixture (5-50% organic content by weight). This parameter change dramatically improves BTA solubility, allowing the solution to be filtered more efficiently with reduced solvent volume, thereby reducing both the time and cost of filtration operations.

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

This approach results in a high BTA concentration polishing slurry with reduced particle scratches, improved performance, and enhanced safety and shipping efficiency by stabilizing the solution for easier handling and transportation.

Implementation Method 1

BTA is dissolved in an ionic surfactant such as a sodium alkyl sulfate solution

Methodology Applied
Scientific EffectSolvation: Solvation

Implementation Method 2

a polyelectrolyte such as polyacrylic acid (PAA) solution

Methodology Applied
Scientific EffectElectrostatic interaction: Electrostatics

Data Source

PatentUS8636917B2Solution for forming polishing slurry, polishing slurry and related methods
Publication Date: 2014.01.28 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A solution for forming a polishing slurry, the polishing slurry and related methods are disclosed. The solution for forming a polishing slurry may include 1H-benzotriazole (BTA) dissolved in an ionic surfactant such as a sodium alkyl sulfate solution, and perhaps a polyacrylic acid (PAA) solution. The solution can be filtered and used in a polishing slurry. This approach to solubilizing BTA results in a high BTA concentration in a polishing slurry without addition of foreign components to the slurry or increased safety hazard. In addition, the solution is easier to ship because it is very stable (e.g., can be frozen and thawed) and has less volume compared to conventional approaches. Further, the polishing slurry performance is vastly improved due to the removal of particles that can cause scratching.