STI CMP Composition With Ceria-Coated Abrasives for Low Dishing

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Solution Overview

Problem

Existing Shallow Trench Isolation (STI) CMP polishing compositions fail to adequately address the need for tunable oxide and HDP film removal rates, tunable SiN film removal rates, and reduced oxide trench dishing, leading to non-uniform trench oxide loss and potential device failure.

Innovation Solution

The use of ceria-coated inorganic oxide abrasive particles in combination with dual chemical additives, including a silicone-containing compound and a non-ionic organic molecule with hydroxyl functional groups, to achieve tunable oxide and SiN film removal rates and reduce oxide trench dishing in STI CMP applications across a wide pH range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional STI CMP polishing compositions are used, then oxide polishing is achieved, but oxide trench dishing occurs leading to non-uniform trench oxide loss

Engineering Contradiction:

Improvetrench oxide loss uniformityVSAvoidoxide trench dishing

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent changes the chemical parameters of the polishing composition by incorporating specific organic compounds (polyols with multiple hydroxyl groups, carboxylic acids with specific pKa values) and adjusting pH ranges to control the chemistry at the polishing interface. This modifies the removal mechanism to reduce dishing while maintaining uniform oxide loss across trenches

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite abrasive particles consisting of ceria-coated inorganic oxide particles, where the ceria coating on the inorganic oxide core provides enhanced chemical reactivity and controlled mechanical properties. This composite structure enables precise control over oxide removal rates and reduces trench dishing

Inventive Principle:

Principle #40Composite materials

2Productivity

If high oxide removal rates are achieved, then polishing efficiency improves, but selectivity between oxide and nitride films decreases

Engineering Contradiction:

Improveoxide removal rateVSAvoidoxide to nitride selectivity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent adjusts chemical parameters including pH (maintained at specific ranges), organic compound concentrations, and abrasive particle characteristics to optimize the chemical-mechanical polishing process. These parameter changes enable high oxide removal rates while maintaining differential removal rates between oxide and nitride films through controlled chemical reactivity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces organic compounds (polyols and carboxylic acids) as intermediaries that mediate the interaction between the polishing composition and the films. These intermediaries selectively enhance oxide removal through chemical complexation while having minimal effect on nitride, thereby maintaining high selectivity

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

This solution enables precise control over oxide and SiN film removal rates, significantly reduces oxide trench dishing, and improves the selectivity between oxide and nitride films, thereby enhancing the reliability and yield of STI CMP processes.

Implementation Method 1

chemical mechanical polishing (CMP) compositions for Shallow Trench Isolation (STI) CMP applications

Methodology Applied

Scientific EffectChemical-mechanical polishing:

Implementation Method 2

abrasive particles and exhibiting normal stress effects

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 3

dual chemical additives, including a silicone-containing compound and a non-ionic organic molecule with hydroxyl functional groups

Methodology Applied

Scientific EffectChemical reaction:

Data Source

PatentUS12234383B2Low dishing oxide CMP polishing compositions for shallow trench isolation applications and methods of making thereof

Publication Date: 2025.02.25 VERSUM MATERIALS US LLC

AI summary

Shallow Trench Isolation (STI) chemical mechanical planarization (CMP) polishing compositions, methods and systems of use therefore are provided. The CMP polishing composition comprises abrasives of ceria coated inorganic oxide particles, such as ceria-coated silica; and dual chemical additives for providing the tunable oxide film removal rates and tunable SiN film removal rates; low oxide trench dishing, and high oxide: SiN selectivity. Dual chemical additives comprise at least one silicone-containing compound comprising at least one of (1) ethylene oxide and propylene oxide (EO-PO) group, and at least one of substituted ethylene diamine group on the same molecule; and (2) at least one non-ionic organic molecule having at least two, preferably at least four hydroxyl functional groups.