Resist Underlayer Composition for EUV Lithography
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Solution Overview
Problem
The semiconductor industry faces challenges in forming ultra-fine patterns with existing lithographic techniques, particularly in achieving high refractive index and low extinction coefficient materials that can handle high-energy wavelengths like EUV and E-beam, while maintaining solubility and durability in solvents.
Innovation Solution
A resist underlayer composition is developed, incorporating a polymer with specific moieties such as cyanuric acid or triazine cores, combined with a third moiety, which provides a high refractive index and low extinction coefficient, along with improved solubility and durability, and includes a cross-linking agent, surfactant, or thermal acid generator for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing lithographic techniques are used, then conventional pattern formation is achieved, but ultra-fine patterns with widths less than 20 nm cannot be formed
Solution Approach 1:
The patent changes the optical parameters of the resist underlayer by selecting materials with specific refractive indices (n>1.5) and extinction coefficients (k<0.3) at 13.5 nm wavelength. This parameter optimization enables effective lithographic patterning at ultra-fine dimensions by controlling light interference and reflectance, thereby achieving reliable formation of patterns with widths less than 20 nm
Solution Approach 2:
The patent employs composite material design by combining organic materials (such as amorphous carbon, hydrocarbons) with specific molecular structures containing heavy atoms or aromatic rings. This composite approach achieves both the required high refractive index and low extinction coefficient while maintaining solubility and processability, enabling ultra-fine pattern formation
2Manufacturing precision
If materials with high refractive index are used, then reflectance control is improved, but solubility deteriorates
Solution Approach 1:
The patent applies local quality by designing molecular structures where specific functional groups or molecular regions provide high refractive index (through heavy atoms, aromatic rings, or specific bonding) while other regions maintain solubility (through polar groups, flexible chains, or solvent-compatible moieties). This spatial separation of functional properties within the material structure resolves the contradiction between reflectance control and solubility
Solution Approach 2:
The patent optimizes molecular weight, molecular weight distribution, and chemical composition parameters to achieve the desired balance. By controlling these parameters, materials with high refractive index can be formulated while maintaining adequate solubility in common solvents, enabling both reflectance control and ease of manufacture
3Manufacturing precision
If materials with low extinction coefficient are used, then light interference effects are minimized, but etch selectivity deteriorates
Solution Approach 1:
The patent optimizes the extinction coefficient parameter to a specific range (k<0.3) that simultaneously achieves low light interference and adequate etch selectivity. This precise parameter control allows the resist underlayer to transmit sufficient light for patterning while maintaining enough optical absorption to provide contrast for etching processes
Solution Approach 2:
The patent uses composite material composition where the resist underlayer combines materials with complementary properties. The composite structure achieves low overall extinction coefficient for minimal light interference while incorporating components that provide sufficient etch selectivity through chemical composition differences between the underlayer and underlying layers
4Ease of manufacture
If conventional resist underlayer materials are used, then basic coating is achieved, but pattern collapse occurs in ultra-fine patterning
Solution Approach 1:
The patent optimizes physical parameters including viscosity, glass transition temperature, and film thickness to prevent pattern collapse. By controlling these parameters within specific ranges, the resist underlayer maintains structural integrity during subsequent processing steps while remaining coatable using standard spin-coating or other conventional coating methods
Solution Approach 2:
The patent performs preliminary optimization of the resist underlayer properties before the actual patterning process. This includes pre-coating to establish a stable foundation layer with appropriate mechanical properties, which prevents pattern collapse during subsequent photoresist coating, exposure, and development steps
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 achieves optimized reflectance, high etch selectivity, and excellent flatness, minimizing light interference effects and pattern collapse, enabling the formation of ultra-fine patterns with widths less than 20 nm using high-energy rays like EUV and E-beam.
Implementation Method 1
achieving high refractive index and low extinction coefficient materials that can handle high-energy wavelengths like EUV and E-beam
Implementation Method 2
low extinction coefficient, along with improved solubility and durability
Data Source
AI summary
A resist underlayer composition and a method of forming patterns, the composition including a solvent; and a polymer having a structure where at least one of a first moiety represented by one of Chemical Formula 1-1 to Chemical Formula 1-3 is combined with a third moiety represented by Chemical Formula 3, or at least one of a second moiety represented by one of Chemical Formula 2-1 to Chemical Formula 2-3 is combined with a third moiety represented by Chemical Formula 3