Alkaline Cleaning Composition for Semiconductor Copper Wiring
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Solution Overview
Problem
Current cleaning liquids for semiconductor substrates with copper wiring after CMP treatments fail to effectively remove metallic impurities and particulates without causing copper corrosion or damaging low permittivity interlayer insulating films.
Innovation Solution
A cleaning liquid composition with a pH of 8 to 10, containing a basic compound and a phosphonic acid-based chelating agent like glycine-N,N-bis(methylenephosphonic acid) or nitrilotris(methylenephosphonic acid), which does not include aqueous hydrogen peroxide or carboxylic acid-based chelating agents, effectively removes metallic impurities and particulates while preventing copper 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, then metal impurity removal is improved, but copper corrosion increases and surface roughness increases
Solution Approach 1:
The patent changes the pH parameter from acidic to alkaline (pH 9.0-11.0) and modifies the chemical composition by using specific alkaline cleaners with controlled metal ion concentrations (0.01-5.0 ppm), thereby achieving effective cleaning without copper corrosion
Solution Approach 2:
The patent introduces metal ion complexing agents as intermediaries that bind to metal ions in the cleaning solution, preventing them from corroding copper surfaces while maintaining cleaning effectiveness
2Reliability
If a basic cleaning liquid is used to remove particulate contamination, then particle removal is improved, but low-k interlayer insulating film damage increases
Solution Approach 1:
The patent precisely controls the pH parameter within a narrow range (9.0-11.0) and limits metal ion concentrations (0.01-5.0 ppm) to achieve sufficient particle removal while minimizing damage to low-k films
Solution Approach 2:
The patent uses a moderate alkaline environment rather than strong alkali, applying partial action to achieve cleaning effectiveness while avoiding excessive damage to sensitive low-k materials
3Productivity
If conventional cleaning liquids are used for post-CMP cleaning, then cleaning capability is improved, but contamination control fails due to inadequate removal of both particulates and metal impurities
Solution Approach 1:
The patent develops a cleaning solution that simultaneously performs multiple functions: removing particulate contamination, dissolving metal impurities, and protecting copper surfaces, thereby achieving comprehensive contamination control in a single step
Solution Approach 2:
The patent creates a composite cleaning solution containing multiple components including alkaline cleaners, metal ion complexing agents, and controlled metal ion concentrations, which work synergistically to address multiple contamination types simultaneously
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 solution provides excellent removability of metallic impurities and particulates without damaging copper surfaces or low-k materials, suppressing surface oxidation and ensuring flatness and cleanliness.
Implementation Method 1
containing one or more phosphonic acid-based chelating agent
Implementation Method 2
having a hydrogen ion concentration (pH) of 8 to 10
Implementation Method 3
preventing copper corrosion by forming a thin oxide film
Data Source
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AI summary
To provide a cleaning liquid composition that has excellent removability for metallic impurities and particulates, does not cause corrosion of Cu, and can clean a semiconductor substrate having copper wiring in a production process for an electronic device such as a semiconductor device. [Solution means] A cleaning liquid composition for cleaning a semiconductor substrate having copper wiring, the cleaning liquid composition containing one or more types of basic compound containing no metal, and one or more types of phosphonic acid-based chelating agent, and having a hydrogen ion concentration (pH) of 8 to 10.