Polishing Composition for Phase Change Alloys Using Brittle Film Formation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional polishing compositions for metal-containing surfaces are inadequate for polishing phase change alloys, as they rely on oxidizing agents and complexing agents that do not effectively address the unique physical properties of phase change materials like GST alloys, leading to inefficient polishing rates.

Innovation Solution

A polishing composition incorporating colloidal silica abrasive grains and a brittle film formation agent, such as saturated monocarboxylic acids or organophosphorus compounds, which forms an insoluble film on the phase change alloy surface, allowing for mechanical polishing without the need for oxidizing agents and complexing agents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional polishing composition containing oxidizing agents and complexing agents is used, then the polishing process can be performed on metal-containing surfaces, but the polishing rate is low for phase change alloys due to their softer physical properties

Engineering Contradiction:
Improvepolishing rateVSAvoidpolishing effectiveness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the polishing slurry by replacing conventional oxidizing agents (hydrogen peroxide) and complexing agents (ammonium hydroxide) with organic acids (acetic acid, formic acid, or their salts). This parameter change adapts the polishing chemistry to match the softer physical properties of phase change alloys, achieving both high polishing rate and effective material removal without excessive etching or dishing.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If polishing composition is designed for conventional metal layers, then it can effectively polish harder materials, but it causes excessive etching and dishing on softer phase change alloy surfaces

Engineering Contradiction:
Improvesurface flatnessVSAvoidpolishing rate
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent substitutes the chemical mechanism of conventional polishing (oxidation followed by complexing etching) with an alternative chemical mechanism based on organic acid dissolution. This substitution creates a more controlled chemical reaction that removes material at a uniform rate across the softer phase change alloy surface, eliminating the dishing and etching problems while maintaining high polishing rate through optimized slurry composition.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If typical polishing composition without brittle film formation agent is used, then the composition is simpler, but it cannot achieve high polishing rate on phase change alloys

Engineering Contradiction:
Improvepolishing rateVSAvoidcomposition complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent creates a composite polishing slurry system that combines organic acids (acetic acid or formic acid and their salts) with abrasive particles and water. This composite composition works synergistically where the organic acid forms a controlled dissolution layer on the phase change alloy surface while abrasive particles mechanically remove the softened material, achieving high polishing rate through the combined chemical-mechanical action of the composite system.

Inventive Principle:
Principle #40Composite materials

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 composition achieves a high polishing rate for phase change alloys by mechanically polishing the insoluble film formed by the brittle film formation agents, improving the efficiency and reducing surface defects.

Implementation Method 1

a brittle film formation agent, such as saturated monocarboxylic acids or organophosphorus compounds, which forms an insoluble film on the phase change alloy surface

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

The composition achieves a high polishing rate for phase change alloys by mechanically polishing the insoluble film formed by the brittle film formation agents

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentUS9631121B2Polishing composition
Publication Date: 2017.04.25 FUJIMI INCORPORATED

AI summary

A polishing composition is used to polish a polishing subject having a phase change alloy. The polishing composition includes abrasive grains and a brittle film formation agent. The brittle film formation agent is at least one or more selected from a saturated monocarboxylic acid and an organophosphorus compound.