Cerium Oxide Slurry for Semiconductor Polishing

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Solution Overview

Problem

Conventional polishing liquids for semiconductor manufacturing have low polishing rates, high polishing scratch generation, and poor storage stability, making it difficult to achieve both high efficiency and effective surface polishing while maintaining additive effects.

Innovation Solution

A slurry using hydroxide particles of tetravalent metal elements with specific light absorption properties is developed, which, when used in an aqueous dispersion, enhances polishing rates and storage stability, and when combined with additives, maintains effective polishing performance and dispersion stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional silica-based polishing liquids are used, then polishing can be performed, but the polishing rate is low

Engineering Contradiction:

Improvepolishing rateVSAvoidpolishing performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the material parameter of the abrasive grains from conventional silica-based materials to cerium oxide-based materials. This parameter change results in significantly improved polishing rate while maintaining reliable polishing performance, directly resolving the technical contradiction between low polishing rate and polishing performance.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If cerium oxide-based polishing liquids are used to improve polishing rate, then polishing scratch is generated

Engineering Contradiction:

Improvepolishing rateVSAvoidpolishing scratch

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by controlling the particle size distribution of cerium oxide abrasive grains, specifically using particles with an average particle diameter of 0.01 μm or less. This localized control of particle characteristics reduces mechanical action at critical locations, thereby minimizing polishing scratch while maintaining high polishing rate.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses excessive chemical action through cerium oxide particles with very small average particle diameter (0.01 μm or less), which enhances chemical etching effect while reducing mechanical scratching. This partial action approach emphasizes chemical removal over mechanical removal, resolving the contradiction between polishing rate and scratch generation.

Inventive Principle:

Principle #16Partial or excessive action

3Manufacturing precision

If additives are added to polishing liquids to improve polishing properties, then storage stability deteriorates

Engineering Contradiction:

Improvepolishing propertiesVSAvoidstorage stability

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent introduces a specific additive comprising a polyvinyl alcohol polymer with controlled molecular weight (10,000-100,000) and saponification degree (70-90%) as an intermediary substance. This mediator maintains stable dispersion of cerium oxide particles during storage while preserving polishing performance, resolving the contradiction between polishing properties and storage stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes specific parameters of the polyvinyl alcohol polymer additive, including molecular weight (10,000-100,000) and saponification degree (70-90%), to achieve the optimal balance between polishing performance and storage stability. These parameter changes enable the additive to effectively stabilize the polishing liquid without compromising polishing properties.

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

The solution achieves high polishing rates and improved storage stability, reducing polishing scratch and maintaining additive effects, even after storage, thereby enhancing the efficiency and quality of semiconductor surface polishing.

Implementation Method 1

the abrasive grain produces absorbance of 1.00 or more and less than 1.50 for light having a wavelength of 400 nm

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS10549399B2Slurry, polishing-solution set, polishing solution, substrate polishing method, and substrate

Publication Date: 2020.02.04 RESONAC CORP

AI summary

A polishing liquid comprising an abrasive grain, an additive, and water, wherein the abrasive grain includes a hydroxide of a tetravalent metal element, and produces absorbance of 1.00 or more and less than 1.50 for light having a wavelength of 400 nm in an aqueous dispersion having a content of the abrasive grain adjusted to 1.0 mass %.