Cleaning Composition for Copper and Low-k Dielectric Substrates
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Solution Overview
Problem
Current cleaning compositions for integrated circuit substrates, particularly those with copper conductors and low-k dielectrics, face challenges in effectively removing photoresist, etching residue, and copper oxide while minimizing damage to the substrate and ensuring compatibility with both materials, especially with low solvent content and high water content formulations.
Innovation Solution
A composition comprising a fluoride-providing component, a water miscible solvent, an acid, and at least 80% water is used to contact the substrate, with specific ratios and pH ranges optimized for batch and single wafer processing methods to efficiently remove residues and copper oxide without damaging the copper and low-k dielectric materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high solvent content compositions are used to remove residues effectively, then cleaning effectiveness is improved, but substrate damage increases and environmental impact worsens
Solution Approach 1:
The patent changes the compositional parameters by using at least 80% water content with reduced solvent content (1-20%), and optimizing pH ranges (1.3-7 for copper compatibility, 4.5-6 for low-k dielectric compatibility). This parameter change allows effective cleaning while reducing substrate damage and environmental impact.
Solution Approach 2:
The invention uses composite cleaning compositions combining multiple components: fluoride-providing components (0.01-0.6% fluorine), water-miscible solvents (1-20%), acids (0.05-5%), and optional chelators (0.001-10%). This composite formulation achieves synergistic effects for effective residue removal while protecting sensitive substrates.
2Productivity
If high solvent content compositions are used to remove residues effectively, then cleaning effectiveness is improved, but environmental impact and cost increase
Solution Approach 1:
The patent reduces solvent content from traditional high levels to 1-20% while increasing water content to at least 80%. This parameter change decreases environmental impact and cost while maintaining cleaning effectiveness through optimized fluoride, acid, and pH combinations.
3Speed
If aggressive cleaning processes are used to remove copper oxide quickly, then cleaning speed is improved, but copper corrosion increases
Solution Approach 1:
The patent optimizes pH ranges (1.3-7 for copper compatibility) and fluoride concentrations (0.01-0.6% fluorine) to achieve effective copper oxide removal while minimizing copper corrosion. The balanced composition enables controlled reaction rates that protect the copper substrate.
Solution Approach 2:
The composite composition combines fluoride-providing components, acids, and optional chelators in specific proportions to achieve synergistic effects that remove copper oxide effectively while protecting the copper substrate from excessive corrosion.
4Productivity
If strong cleaning compositions are used to remove all residues, then cleaning effectiveness is improved, but low-k dielectric damage increases
Solution Approach 1:
The patent optimizes pH ranges (4.5-6 for low-k dielectric compatibility) and solvent content (1-20%) to achieve effective residue removal while protecting low-k dielectric materials from damage such as etching, porosity changes, and dielectric property degradation.
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 high-water-content compositions provide effective and cost-efficient removal of residues and copper oxide, minimizing substrate damage and environmental impact, while maintaining low copper corrosion rates and dielectric properties, suitable for both batch and single wafer processing.
Implementation Method 1
contacting the substrate with a composition comprising: a fluoride-providing component; at least 1% by weight of a water miscible solvent; an acid; and at least 80% by weight water, for a time and at a temperature sufficient to remove the resist, residues, and copper oxide
Implementation Method 2
the composition comprises a fluoride species... effective removal of photoresist, etching residue, and copper oxide from substrates having copper and low-k dielectric material
Data Source
AI summary
A variety of compositions that are particularly applicable for removing one or more of resist, etching residue, planarization residue, and copper oxide from a substrate comprising copper and a low-k dielectric material are described. The resist, residues, and copper oxide are removed by contacting the substrate surface with the composition, typically for a period of 30 seconds to 30 minutes, and at a temperature between 25° and 45° C. The composition includes a fluoride-providing component; at least 1% by weight of a water miscible organic solvent; an organic acid; and at least 81% by weight water. Typically the composition further includes up to about 0.4% of one or more chelators.