Basic Cleaning Liquid for Semiconductor Cu Wiring
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Solution Overview
Problem
Current cleaning liquids for semiconductor substrates with Cu wiring fail to effectively remove metallic impurities, particulates, and organic residues without causing corrosion or damaging low-permittivity interlayer insulating films, and they lack sufficient removability of Cu-containing organic residues.
Innovation Solution
A cleaning liquid composition comprising one or more basic compounds and nitrogen atom-containing heteromonocyclic aromatic compounds, with a pH of 8 to 11, which does not contain isoascorbic acid, ascorbic acid, or gallic acid, is used to remove metallic impurities and particulates, particularly Cu-containing organic residues, while preventing Cu corrosion by forming a thin oxide film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an acidic cleaning liquid is used to remove metal contamination and particulate contamination, then removability of contaminants is improved, but Cu corrosion increases and surface roughness increases
Solution Approach 1:
The patent changes the pH parameter from acidic to basic (pH 9.0-11.0) to eliminate Cu corrosion while maintaining contaminant removability. This parameter change fundamentally alters the cleaning mechanism from acid-based dissolution to base-based emulsification and suspension, resolving the contradiction between contaminant removal and Cu protection
Solution Approach 2:
The patent uses a composite cleaning liquid containing multiple basic compounds (quaternary ammonium hydroxide, amine, alcohol amine) combined with specific surfactants and chelating agents. This composite formulation achieves effective contaminant removal through synergistic actions while the basic environment protects Cu from corrosion, unlike single-component acidic cleaners
2Reliability
If a basic cleaning liquid is used to remove particulate contamination, then particle removal is improved, but low-k interlayer insulating film is damaged
Solution Approach 1:
The patent optimizes the pH parameter to a specific basic range (pH 9.0-11.0) that is strong enough to remove particles effectively but not so strong as to damage low-k films. This precise parameter control allows the basic cleaning liquid to achieve particle removal without the film damage caused by stronger bases
Solution Approach 2:
The patent employs surfactants that provide localized action at the contaminant-surface interface, enabling effective particle removal through emulsification and suspension mechanisms that are gentler on the low-k film bulk material compared to uniform strong base exposure
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 cleaning liquid composition achieves excellent removability of metallic impurities and organic residues without corroding Cu surfaces, suppresses further oxidation, and protects the cleaned Cu surface with a thin oxide film, ensuring effective cleaning and planarity without damaging low-k materials.
Implementation Method 1
suppresses further oxidation by protecting a cleaned Cu surface with a thin oxide film
Implementation Method 2
excellent removability for impurities such as metallic impurities, particulates, and organic residue
Data Source
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AI summary
The purpose of the present invention is to provide a cleaning liquid composition useful in cleaning substrates, etc., which have undergone treatment such as chemical mechanical polishing (CMP) in a process for manufacturing electronic devices such as semiconductor elements. This cleaning liquid composition for cleaning substrates having Cu wiring includes one or more basic compounds and one or more heteromonocyclic aromatic compounds containing a nitrogen atom, and has a hydrogen ion concentration (pH) of 8-11.