CMP Post-Cleaning Composition for Semiconductor Wafer Contaminant Removal
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Solution Overview
Problem
Conventional chemical-mechanical polishing (CMP) processes leave contaminants on semiconductor wafers, such as silica or alumina abrasive particles and metal ions, which are difficult to completely remove and can cause corrosion and roughness, affecting wafer performance.
Innovation Solution
A cleaning composition comprising bulky protecting ligands like maleic acid and quaternary ammonium hydroxide, organic amines, and organic inhibitors like carbohydrazide, which effectively removes contaminants while minimizing corrosion and roughness by reacting with reactive sites on the wafer surface and controlling metal oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CMP processes are used to polish semiconductor wafers, then the wafer surface is planarized, but contaminants such as abrasive particles and metal ions remain on the surface
Solution Approach 1:
The patent separates the polishing and cleaning functions into distinct steps. The CMP process focuses solely on achieving surface planarity, while a subsequent dedicated cleaning step removes contaminants. This segmentation allows each process to optimize for its specific function without compromise.
Solution Approach 2:
The patent introduces an intermediary cleaning step between CMP and subsequent processing. This intermediary process uses chelating agents and surfactants to bind and remove metal ions and organic residues that remain after polishing, preventing contamination without affecting the achieved planarity.
2Object-generated harmful factors
If aqueous cleaning solutions are used to remove contaminants after CMP, then some contaminants are removed, but corrosion and roughness still occur on the wafer surface
Solution Approach 1:
The patent changes the chemical parameters of the cleaning solution by using chelating agents (such as EDTA, DTPA) that specifically bind metal ions, and adjusting pH levels to optimize cleaning while minimizing corrosion. This parameter optimization allows effective contaminant removal without the harmful side effects of conventional acidic or basic solutions.
Solution Approach 2:
The cleaning composition is a composite formulation containing multiple functional components: chelating agents for metal ion removal, surfactants for organic residue removal, and corrosion inhibitors. This composite approach provides multi-functional cleaning that addresses various contaminant types simultaneously while protecting the wafer surface.
3Object-generated harmful factors
If cleaning compositions are designed to remove all contaminants, then cleaning effectiveness improves, but corrosion of the wafer surface increases
Solution Approach 1:
The chelating agents act as intermediaries that selectively bind to metal ions, allowing their removal without requiring aggressive acidic or basic conditions that would corrode the wafer. This intermediary binding mechanism enables gentle yet effective cleaning.
Solution Approach 2:
The patent converts the potentially harmful effect of metal ion presence into a benefit by using chelating agents that selectively bind and solubilize metal ions, transforming them from corrosive contaminants into removable complexes that can be gently washed away without damaging the wafer surface.
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 composition reduces surface roughness to 3 Å or less and minimizes corrosion, enhancing conductivity and enabling advanced node polishing with better performance properties, particularly suitable for semiconductor wafers with low dielectric constants.
Implementation Method 1
The composition comprises, consists of, or consists essentially of: (a) a bulky protecting ligand
Implementation Method 2
the one or more organic amines are present in an amount of from about 0.01 wt.％ to about 5 wt.％ based on the total weight of the composition, the bulky protecting ligand or combinations thereof are present in an amount of at least 3 wt.％ based on the total weight of the composition
Data Source
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AI summary
The invention provides a composition for cleaning contaminants from semiconductor wafers following chemical-mechanical polishing. The cleaning composition contains a bulky protecting ligand, an organic amine, an organic inhibitor, and water. The invention also provides methods for using the cleaning composition.