Post-CMP Cleaning Composition for Copper Surface Passivation Removal
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Solution Overview
Problem
Current post-CMP cleaning compositions fail to effectively remove benzotriazole residues and contaminants from copper-containing surfaces without increasing surface roughness or introducing environmental and safety concerns, and often require multiple steps and organic solvents.
Innovation Solution
A post-CMP cleaning composition comprising cysteine, glutathione, or thiourea, along with a sugar alcohol and a metal chelating agent, applied in a moderate pH range of 4 to 7, which efficiently removes benzotriazole films and other contaminants without increasing surface roughness or using organic solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional post-CMP cleaning compositions are used, then cleaning action is provided, but benzotriazole residues and contaminants cannot be effectively removed and surface roughness increases
Solution Approach 1:
The invention changes the chemical composition parameters of the cleaning solution by incorporating specific sulfur-containing compounds (cysteine, glutathione, or thiourea) at controlled concentrations (0.01-5 wt%, preferably 0.1-1 wt%). This compositional parameter change enables effective removal of benzotriazole residues while maintaining surface smoothness, resolving the contradiction between cleaning efficacy and surface roughness control.
Solution Approach 2:
The invention creates a composite cleaning solution by combining sulfur-containing compounds with sugar alcohols (0.1-5 wt%) and metal chelating agents (0.01-1 wt%). This composite formulation synergistically achieves both effective contaminant removal and surface roughness control, addressing the contradiction between cleaning performance and surface quality.
2Reliability
If multiple cleaning steps and organic solvents are used, then cleaning completeness is improved, but environmental and safety concerns increase and process complexity increases
Solution Approach 1:
The invention extracts and eliminates harmful organic solvents from the cleaning process by using a water-based formulation with sulfur-containing compounds. This single-step aqueous solution achieves complete cleaning without the environmental and safety issues associated with organic solvents, resolving the contradiction between cleaning completeness and harmful factors.
Solution Approach 2:
The invention changes the fundamental parameter of the cleaning medium from organic-based to water-based, using sulfur-containing compounds dissolved in water. This parameter change eliminates environmental and safety concerns while maintaining or improving cleaning effectiveness through the unique chemical properties of the sulfur compounds.
3Productivity
If stronger cleaning agents are used, then contaminant removal efficiency is improved, but surface roughness increases and corrosion risk increases
Solution Approach 1:
The invention changes the chemical nature of the cleaning agent from strong conventional cleaners to mild sulfur-containing compounds (cysteine, glutathione, or thiourea). These compounds achieve high contaminant removal efficiency through specific chemical interactions with benzotriazole residues while being gentle enough to prevent surface roughening and corrosion.
Solution Approach 2:
The sulfur-containing compounds act as intermediary substances that mediate between the cleaning requirement and surface protection. They chemically interact with and remove benzotriazole contaminants while simultaneously protecting the copper surface from corrosion and roughness increase, resolving the contradiction between removal efficiency and surface quality.
4Reliability
If conventional cleaning compositions are used, then general cleaning is achieved, but copper surface corrosion is not effectively prevented
Solution Approach 1:
The sulfur-containing compounds (cysteine, glutathione, or thiourea) serve as dual-function intermediaries: they clean the copper surface by removing contaminants while simultaneously acting as corrosion inhibitors. The sulfur groups in these compounds bind to copper ions, preventing corrosion without compromising cleaning performance.
Solution Approach 2:
The invention makes the cleaning solution multi-functional by incorporating sulfur-containing compounds that simultaneously provide cleaning action and corrosion protection. This single composition achieves both contaminant removal and surface protection, resolving the contradiction between corrosion prevention and cleaning effectiveness.
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 effectively prevents corrosion and removes passivation films, ensuring clean copper surfaces and reducing defects, suitable for high-precision fabrication methods like copper damascene processes, while being environmentally friendly and requiring minimal steps.
Implementation Method 1
a post chemical-mechanical-polishing (post-CMP) cleaning composition comprising a specific sulfur-containing compound... efficiently removes benzotriazole films and other contaminants
Implementation Method 2
The sulfur-containing compound... prevents corrosion and removes passivation films
Implementation Method 3
along with a sugar alcohol and a metal chelating agent... effectively prevents corrosion and removes passivation films
Data Source
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AI summary
A post chemical-mechanical-polishing (post-CMP) cleaning composition comprising: (A) is cysteine, glutathione, N-acetylcysteine, thiourea, (L) at least one oligomeric or polymeric polycarboxylic acid, and (C) water, wherein the post-CMP cleaning composition has a pH-value in the range of from 4 to not more than 7. The use of the composition for removing residues and contaminants from the surface of semiconductor substrates useful for manufacturing microelectronic devices. A process for manufacturing microelectronic devices from semiconductor substrates comprising the step of removing residues and contaminants from the surface of the semiconductor substrates by contacting them at least once with the post-CMP cleaning composition.