Nitrogen-Free Cleaning Composition for Semiconductor Substrates

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Solution Overview

Problem

Existing aqueous post-CMP cleaning compositions for semiconductor substrates face issues such as increased surface roughness, corrosion, and damage to copper surfaces due to redox reactions, galvanic corrosion, and the inability to efficiently remove abrasive particles, leading to defects and the need for strong etchants and organic solvents.

Innovation Solution

Aqueous, nitrogen-free cleaning composition with a pH range of 5 to 8, comprising amphiphilic nonionic surfactants and polycarboxylic acid chelating agents, which effectively removes residues and contaminants without increasing surface roughness, reducing corrosion, and avoiding the use of strong copper inhibitors and organic solvents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If aqueous alkaline cleaning compositions containing amines and passivating agents are used, then residues and contaminants can be removed from the substrate surface, but surface roughness increases and corrosion occurs due to redox reactions

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidsurface roughness and corrosion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical parameters of the cleaning composition by using a neutral pH range (5-8) instead of strongly alkaline conditions, and by selecting specific surfactants and chelating agents that do not cause redox reactions, thereby eliminating corrosion and surface roughness while maintaining cleaning effectiveness

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces strong, damaging cleaning chemicals with milder, environmentally friendly alternatives consisting of nonionic surfactants and polycarboxylic acids that achieve cleaning without causing harm to the substrate

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Productivity

If strong etchants are used to remove abrasive particles, then particle removal efficiency improves, but damage to copper and dielectric materials increases

Engineering Contradiction:

Improveparticle removal efficiencyVSAvoiddamage to copper and dielectric materials

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The invention introduces surfactants as intermediary substances that mediate between the cleaning composition and the abrasive particles, enabling particle removal through surfactant-particle interactions rather than through damaging chemical etching of the substrate

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention replaces the mechanical/chemical etching mechanism with a surfactant-based cleaning mechanism that relies on surface activity and chelation rather than aggressive chemical reactions, thereby removing particles without damaging the substrate

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If nitrogen-containing cleaning compositions are used, then cleaning performance is achieved, but environmental impact increases due to ammonia emissions

Engineering Contradiction:

Improvecleaning performanceVSAvoidenvironmental impact and ammonia emissions

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention extracts and removes nitrogen-containing components from the cleaning composition, eliminating the source of ammonia emissions while replacing them with nitrogen-free alternatives such as nonionic surfactants and polycarboxylic acids that maintain cleaning performance without environmental harm

Inventive Principle:

Principle #2Taking out (Extraction)

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 efficiently removes contaminants and residues without causing etching or corrosion, maintaining surface integrity and avoiding damage to copper and low-k dielectric materials, resulting in high-reliability microelectronic devices with reduced environmental impact.

Implementation Method 1

amphiphilic nonionic surfactants

Methodology Applied

Scientific EffectSurfactant: Surfactant

Implementation Method 2

amphiphilic nonionic, water-soluble or water-dispersible surfactants

Methodology Applied

Scientific EffectWetting: Wetting

Implementation Method 3

polycarboxylic acid chelating agents

Methodology Applied

Scientific EffectChelation:

Data Source

PatentUS9275851B2Aqueous, nitrogen-free cleaning composition and its use for removing residues and contaminants from semiconductor substrates suitable for manufacturing microelectronic devices

Publication Date: 2016.03.01 BASF SE

AI summary

Aqueous, nitrogen-free cleaning composition, preparation and use thereof are provided. The composition having a pH of from 5 to 8 comprises (A) an amphiphilic nonionic, water-soluble or water-dispersible surfactant and (B) a metal chelating agent selected from polycarboxylic acids having at least 3 carboxylic acid groups. The composition is used for removing residues and contaminants from semiconductor substrates.