CMP Polishing Liquid for Silicon Stopper Defect Suppression

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Solution Overview

Problem

Current semiconductor manufacturing processes face challenges in suppressing defects, particularly in silicon-based stopper materials like polysilicon and single-crystal silicon during chemical mechanical polishing (CMP), which affect the reliability and performance of semiconductor devices as they become more dense and miniaturized.

Innovation Solution

A polishing liquid containing abrasive grains, a first nitrogen-containing compound with specific structural features, and a second nitrogen-containing compound with a high HLB value, which together inhibit defect formation by forming protective bonds with the silicon material surface, preventing chemical action-induced defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional polishing liquids are used to polish silicon-based stopper materials, then the polishing process can be completed, but defects occur in the stopper material affecting semiconductor device reliability

Engineering Contradiction:

Improvedefect suppression in stopper materialVSAvoiddifficulty in suppressing defects with conventional polishing liquids

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by modifying the chemical composition parameters of the polishing liquid. Specifically, it controls the pH value within 2-8 and precisely controls the concentration ratio of nitrogen-containing compound to silicon oxide particles (0.01-10 mass%). These parameter optimizations enable effective defect suppression in silicon-based stopper materials while maintaining manufacturing feasibility

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining multiple components in the polishing liquid: silicon oxide particles (abrasive), nitrogen-containing compounds (defect suppression agents), and water as solvent. This composite formulation creates synergistic effects where the nitrogen-containing compounds protect the silicon stopper material from chemical damage while the silicon oxide particles provide mechanical polishing action

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If polishing is performed on silicon-based stopper materials, then the insulating material can be removed to expose the stopper, but chemical action causes recessed defects in the stopper

Engineering Contradiction:

Improvepolishing selectivity between insulating material and stopperVSAvoidchemical action-induced defects in stopper

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The nitrogen-containing compound acts as an intermediary substance that mediates between the abrasive particles and the silicon stopper material. It forms a protective layer or complex on the silicon surface that prevents direct chemical attack from the polishing environment, thereby suppressing recessed defects while allowing controlled mechanical removal of insulating material

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The nitrogen-containing compound creates a chemically inert environment at the silicon stopper surface during polishing. By introducing nitrogen-based protective species, it prevents unwanted chemical reactions between the silicon material and other components in the polishing liquid, effectively suppressing defect formation

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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 proposed solution effectively suppresses the occurrence of defects in silicon-based stopper materials during polishing, enhancing the reliability and performance of semiconductor devices by ensuring a smoother, more reliable surface finish.

Implementation Method 1

forming protective bonds with the silicon material surface, preventing chemical action-induced defects

Methodology Applied

Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 2

abrasive grains

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentUS11926764B2Polishing solution, polishing solution set, polishing method, and defect suppressing method

Publication Date: 2024.03.12 RESONAC CORP

AI summary

A polishing liquid containing: abrasive grains; a first nitrogen-containing compound; a second nitrogen-containing compound; and water, in which the first nitrogen-containing compound contains at least one selected from the group consisting of (I) a compound having an aromatic ring containing one nitrogen atom in the ring and a hydroxyl group, (II) a compound having an aromatic ring containing one nitrogen atom in the ring and a functional group containing a nitrogen atom, (III) a compound having a 6-membered ring containing two nitrogen atoms in the ring, (IV) a compound having a benzene ring and a ring containing a nitrogen atom in the ring, and (V) a compound having a benzene ring to which two or more functional groups containing a nitrogen atom are bonded, and an HLB value of the second nitrogen-containing compound is 7 or more.