Post-CMP Cleaning Composition for Residue Removal Without Metal Corrosion

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Solution Overview

Problem

Existing cleaning methods for semiconductor substrates after chemical mechanical polishing (CMP) are inadequate in terms of cleaning performance and corrosion prevention, particularly for metal films like Cu-, W-, and Co-containing films.

Innovation Solution

A cleaning method using a cleaning liquid with a specific composition comprising amines and a compound represented by Formula (a), with a mass ratio of component B to component A not exceeding 0.01, and a temperature of at least 30°C, which includes optional components like chelating agents and surfactants for enhanced cleaning and corrosion prevention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional cleaning liquids are used for post-CMP cleaning, then cleaning performance is insufficient, but corrosion prevention performance deteriorates

Engineering Contradiction:

Improvecleaning performanceVSAvoidcorrosion prevention performance

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the cleaning liquid by specifying precise mass ratios of component B to component A (not more than 0.01), and controlling the content of component B (0.01 wt% or more). This parameter optimization enables the cleaning liquid to achieve both high cleaning performance and corrosion prevention performance simultaneously, resolving the technical contradiction between these two functions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite cleaning liquid system by combining component A (surfactant), component B (chelating agent), and optional components (reducing agent, buffer agent, organic solvent, water) in specific proportions. This composite formulation synergistically provides both cleaning and corrosion prevention functions, overcoming the limitation of conventional single-function cleaning liquids.

Inventive Principle:

Principle #40Composite materials

2Object-generated harmful factors

If cleaning liquids with higher cleaning performance are used, then residues are removed more effectively, but metal film corrosion increases

Engineering Contradiction:

Improveresidue removalVSAvoidmetal film corrosion

Core Design Contradiction:

Object-generated harmful factorsVSObject-affected harmful factors

Solution Approach 1:

The patent introduces component B (chelating agent) as an intermediary substance that mediates between the cleaning action and the metal film. The chelating agent binds to metal ions, preventing them from causing corrosion while allowing the surfactant to effectively remove organic and inorganic residues. This intermediary mechanism resolves the contradiction between aggressive cleaning and metal film protection.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts potentially harmful metal ions released during CMP polishing into beneficial chelated complexes through the addition of component B. By transforming free metal ions (which cause corrosion) into stable chelated forms, the cleaning liquid simultaneously achieves effective residue removal and corrosion prevention.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 method provides improved cleaning performance and corrosion prevention for semiconductor substrates post-CMP, effectively removing residues while protecting metal films.

Implementation Method 1

a cleaning liquid shows alkaline properties and contains: a component A that is at least one selected from the group consisting of a primary amine, a secondary amine, a tertiary amine, and their salts... and a component B that is a compound represented by Formula (a)... wherein a mass ratio of a content of the component B to a content of the component A is not more than 0.01

Methodology Applied

Scientific EffectComplexation:

Implementation Method 2

the cleaning liquid applied to the semiconductor substrate has a temperature of not lower than 30° C.... wherein a mass ratio of a content of the component B to a content of the component A is not more than 0.01... a component B that is a compound represented by Formula (a)... NHxR(3-x) (a) where R represents an alkyl group having 1 to 3 carbon atoms

Methodology Applied

Scientific EffectChelation:

Data Source

PatentUS12374540B2Post-CMP semiconductor cleaning composition comprising an amine/alkanolamine mixture

Publication Date: 2025.07.29 FUJIFILM CORP

AI summary

There is provided a method of cleaning semiconductor substrates that is excellent in cleaning performance with respect to semiconductor substrates having undergone a chemical mechanical polishing process and corrosion prevention performance with respect to metal films. This method includes a cleaning step of cleaning a semiconductor substrate having undergone the CMP using a cleaning liquid. The cleaning liquid shows alkaline properties and contains: a component A that is at least one selected from the group consisting of a primary amine, a secondary amine, and a tertiary amine, provided that a compound represented by a specific formula (a) is excluded; and a component B that is a compound represented by the specific formula (a). The mass ratio of the component B content to the component A content is not more than 0.01. The cleaning liquid applied to the semiconductor substrate has a temperature of not lower than 30° C.