Polishing Composition for SiC and GaN via Metal Salt Oxidation

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Solution Overview

Problem

Existing polishing compositions for materials like silicon carbide and gallium nitride often result in scratches and defects due to low pH levels, which can damage equipment and limit polishing removal rates.

Innovation Solution

A polishing composition containing water, an abrasive, an oxidant, and a metal salt (such as an alkali or alkaline earth metal salt) is used, with specific concentration ratios and types of oxidants like potassium permanganate, to enhance the polishing removal rate while minimizing defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a polishing composition with low pH is used to achieve sufficient polishing removal rate, then the polishing removal rate is improved, but the polishing machine and peripheral members may be damaged

Engineering Contradiction:
Improvepolishing removal rateVSAvoiddamage to polishing machine and peripheral members
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical parameters of the polishing composition by using metal salts (alkali or alkaline earth metal salts) instead of traditional low pH formulations. This parameter change allows achieving high polishing removal rates while maintaining neutral or near-neutral pH levels, thereby preventing damage to polishing machines and peripheral members.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the traditional mechanical abrasion-based polishing mechanism with a chemical-mechanical polishing mechanism. By introducing metal salts that facilitate chemical reactions on the material surface, the polishing process becomes more efficient and less dependent on aggressive mechanical forces and low pH conditions, reducing equipment damage.

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

2Object-affected harmful factors

If traditional polishing methods are used to avoid equipment damage, then equipment safety is maintained, but the polishing removal rate is limited

Engineering Contradiction:
Improveequipment damageVSAvoidpolishing removal rate
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent introduces metal salts as intermediary substances that mediate between the polishing composition and the material surface. These metal salts facilitate chemical reactions that soften or alter the surface layer, making it easier to remove with minimal mechanical stress, thereby achieving high removal rates without equipment damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite polishing composition system combining metal salts, oxidants, and abrasives. This composite formulation synergistically combines chemical etching capabilities with mechanical abrasion, enabling high polishing removal rates while operating under gentle conditions that protect equipment.

Inventive Principle:
Principle #40Composite materials

3Productivity

If diamond abrasive is used for lapping to achieve material removal, then the polishing removal rate is improved, but defects and strains occur due to scratches

Engineering Contradiction:
Improvepolishing removal rateVSAvoidsurface quality with defects and scratches
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces harsh mechanical lapping with diamond abrasive with a chemical-mechanical polishing process. The metal salts and oxidants chemically modify the surface, reducing the need for aggressive mechanical removal that causes scratches and defects, thereby improving surface quality while maintaining removal efficiency.

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

Solution Approach 2:

The patent introduces metal salts and oxidants as intermediary agents that chemically prepare the surface before mechanical polishing. This chemical pre-treatment reduces the hardness or alters the surface structure, allowing for defect-free removal of material without the scratches typically caused by direct diamond abrasive contact.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 removal rate with reduced defects and equipment damage, suitable for materials with high hardness like silicon carbide and gallium nitride, improving surface quality and efficiency.

Implementation Method 1

The polishing composition contains water, an abrasive, an oxidant, and a polishing removal accelerator

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

The polishing composition contains water, an abrasive, an oxidant, and a polishing removal accelerator

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentUS11339311B2Polishing composition
Publication Date: 2022.05.24 FUJIMI INCORPORATED

AI summary

The present invention provides a polishing composition with which polishing rates can be effectively improved and which is for polishing works to be polished. The polishing composition comprises water, abrasive grains, an oxidant, and a polishing accelerator. The polishing accelerator comprises at least one metal salt selected from the group consisting of alkali metal salts and alkaline-earth metal salts.