Cerium Oxide CMP Slurry for High Oxide-Nitride Selectivity

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Solution Overview

Problem

Conventional cerium oxide slurries face challenges in achieving high oxide film removal rates with small particle sizes, leading to polishing scratches and inadequate nitride film polishing selectivity, which are exacerbated by further semiconductor miniaturization.

Innovation Solution

A chemical mechanical polishing (CMP) slurry composition comprising cerium oxide particles with a high Ce3+ content, a cationic polymer, and a nitride film passivation modifier, optimized for high oxide film polishing rates and reduced nitride film polishing, maintaining a transparent and monodispersed state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the average particle diameter of cerium oxide particles is reduced to minimize polishing scratches, then the mechanical action is reduced and the polishing rate is reduced

Engineering Contradiction:

Improvepolishing scratchesVSAvoidpolishing rate

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent changes the chemical composition parameters of cerium oxide particles by controlling the Ce3+/Ce4+ ratio through specific synthesis conditions (pH control during precipitation). This chemical parameter change enables small particles to achieve high polishing rates through enhanced chemical reactivity, compensating for reduced mechanical action.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite slurry system combining cerium oxide particles with specific additives (anionic surfactants, chelating agents) to enhance the overall polishing performance. The composite formulation allows small particles to maintain high polishing rates while minimizing scratches.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If conventional cerium oxide particles are used with small particle size, then polishing scratches are reduced, but the oxide film removal rate is insufficient

Engineering Contradiction:

Improvepolishing scratchesVSAvoidoxide film removal rate

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent fundamentally changes the surface chemical state of cerium oxide particles by controlling the Ce3+ content through pH-controlled precipitation during synthesis. This parameter change increases chemical reactivity toward oxide films, enabling high removal rates even with small particle sizes that minimize scratching.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the Ce3+ to Ce4+ ratio of cerium oxide particles is not optimized, then the oxide film polishing rate is insufficient, but optimizing this ratio requires specific synthesis conditions that increase manufacturing complexity

Engineering Contradiction:

Improveoxide film polishing rateVSAvoidsynthesis process complexity

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent identifies pH as a critical synthesis parameter that directly controls the Ce3+/Ce4+ ratio. By establishing specific pH ranges during precipitation, the method achieves optimal Ce3+ content (30-70 atomic %) and high oxide film polishing rates while maintaining manufacturability through a controllable single-parameter process.

Inventive Principle:

Principle #35Parameter changes

4Productivity

If conventional CMP slurry composition is used, then the nitride film polishing rate is high, but the fine pattern passivation is inadequate

Engineering Contradiction:

Improvenitride film polishing rateVSAvoidfine pattern passivation

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent introduces anionic surfactants as intermediary substances that adsorb onto nitride film surfaces, creating a protective layer that reduces polishing rate and prevents over-polishing of fine patterns. This intermediary mechanism enables better passivation control while maintaining adequate polishing performance.

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 high oxide film removal rates with minimized surface defects and nitride film polishing, enhancing semiconductor device manufacturing precision and reducing polishing scratches.

Implementation Method 1

increasing the ratio of Ce3+ on the cerium oxide surface... to have a high oxide film removal rate

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

through an appropriate additive component, to reduce nitride film polishing rate for passivation of fine patterns

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 3

cerium oxide particles having a size less than 10 nm, which are obtained through precipitation in a solution

Methodology Applied

Scientific EffectPrecipitation: Precipitation

Data Source

PatentUS20250313721A1Chemical-mechanical polishing slurry composition and method for manufacturing semiconductor device

Publication Date: 2025.10.09 SOULBRAIN CO LTD

AI summary

Cerium oxide particles for chemical-mechanical polishing and a chemical-mechanical polishing slurry composition comprising same are described. By combining the cerium oxide particles that are characteristic with a cationic polymer and a nitride film passivation modifier, it is possible to provide a slurry composition for chemical-mechanical polishing that can maximize the silicon oxide/nitride film selection ratio during an STI polishing process while improving the oxide film polishing speed, and a method for manufacturing a semiconductor device utilizing the slurry composition.