Molybdenum CMP Composition for High Mo:TEOS and Mo:SiN Selectivity

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Solution Overview

Problem

Current CMP compositions for molybdenum polishing suffer from low Mo:TEOS and Mo:SiN removal rate ratios, leading to prolonged polishing processes and surface scratches, necessitating compositions that provide high Mo removal rates with low TEOS and SiN removal rates.

Innovation Solution

A polishing composition comprising colloidal silica abrasive, a zwitterionic surfactant as a molybdenum etching inhibitor, and hydrogen peroxide oxidizer, formulated at a pH of 6.5 to 8.5, which excludes iron ions to enhance Mo and W removal rates while minimizing TEOS and SiN removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If current polishing compositions are used to achieve high molybdenum removal rates, then Mo removal rate is improved, but TEOS and SiN removal rates also increase leading to low selectivity ratios

Engineering Contradiction:

Improvemolybdenum removal rateVSAvoidMo:TEOS and Mo:SiN removal rate selectivity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the chemical parameters of the polishing composition by using a zwitterionic surfactant (specifically alkyl amine oxide with 8-14 carbon atoms) as etching inhibitor and hydrogen peroxide as oxidizer at controlled concentrations. This chemical parameter change enables high Mo removal rate while maintaining low TEOS and SiN removal rates, achieving selectivity ratios of Mo:TEOS > 50 and Mo:SiN > 100.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs hydrogen peroxide as a strong oxidizer to accelerate the chemical oxidation of molybdenum during CMP. This strong oxidizing action enhances the removal rate of molybdenum while the zwitterionic surfactant selectively inhibits the oxidation of underlying dielectric materials, thereby achieving high selectivity.

Inventive Principle:

Principle #38Strong oxidants (Accelerated oxidation)

2Productivity

If polishing speed is increased to improve throughput, then productivity is improved, but surface scratches increase and selectivity decreases

Engineering Contradiction:

Improvepolishing throughputVSAvoidsurface scratches

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent adjusts the pH parameter to ranges of 6.5-8.5 and controls the concentrations of hydrogen peroxide (0.1-5 wt%) and zwitterionic surfactant (0.01-0.5 wt%) to optimize the chemical-mechanical polishing conditions. These parameter changes enable higher polishing speeds without generating surface scratches while maintaining high selectivity ratios.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If polishing time is extended to achieve desired removal rates, then manufacturing precision is improved, but process duration increases

Engineering Contradiction:

Improvesurface planarityVSAvoidpolishing process time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The use of hydrogen peroxide as a strong oxidizer accelerates the chemical oxidation of molybdenum, enabling faster material removal rates. This reduces the polishing time required to achieve the desired removal rates and surface planarity, improving overall process efficiency.

Inventive Principle:

Principle #38Strong oxidants (Accelerated oxidation)

Solution Approach 2:

The optimized pH range (6.5-8.5) and controlled concentrations of chemical additives create favorable conditions for rapid and selective molybdenum removal, reducing the time required to achieve target planarity while maintaining high selectivity against underlying materials.

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 composition achieves high Mo and W removal rates with selective Mo:TEOS and Mo:SiN removal, reducing surface scratches and improving process throughput.

Implementation Method 1

the molybdenum etching inhibitor is a zwitterionic surfactant

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

the abrasive is colloidal silica with a mean particle size ranging from about 30 to about 75 nm

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 3

the oxidizer is a peroxide

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS12448544B2Chemical mechanical polishing compositions and methods of use thereof

Publication Date: 2025.10.21 FUJIMI INCORPORATED

AI summary

The present disclosure relates to chemical mechanical polishing (CMP) compositions for polishing molybdenum surfaces. In particular, the CMP composition includes an abrasive, a molybdenum (Mo) etching inhibitor, an oxidizer, and water, combined in specified amounts to provide a composition with advantageous properties such as high Mo:TEOS removal rate selectivity and/or high Mo:SiN removal rate selectivity.