Lithography Upper-Layer Film Composition Defect Control
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Solution Overview
Problem
In liquid immersion lithography, existing upper-layer films face challenges with moderate water repellency, high solubility in developers, and the occurrence of defects like watermark and bridge defects, especially at high scan speeds.
Innovation Solution
A liquid immersion lithography upper-layer film-forming composition incorporating specific polymers with structural units such as (I), (II), (III), and (IV), and a solvent, which provides moderate water repellency and high solubility, preventing defects like watermark and bridge defects even at high scan speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid immersion lithography upper-layer film with high water repellency (high hydrophobicity) is used, then watermark defects are suppressed, but bridge defects occur due to low solubility in the developer
Solution Approach 1:
The patent changes the chemical composition parameters of the upper-layer film by incorporating specific polymer structures (carboxyl-containing polymers, sulfonic acid-containing polymers, fluorine-containing polymers) with controlled molecular weights and compositions. This allows tuning of the film's properties to achieve moderate water repellency while maintaining high solubility in the developer, preventing both watermark and bridge defects
Solution Approach 2:
The patent uses composite material approaches by combining multiple polymer types in the upper-layer film formulation. The composition includes carboxyl-containing polymers, sulfonic acid-containing polymers, and fluorine-containing polymers in specific ratios, creating a composite material that balances water repellency and developer solubility to prevent both types of defects
2Productivity
If the scan speed is increased to improve production efficiency, then productivity increases, but watermark defects occur due to immersion medium not following lens movement
Solution Approach 1:
The patent applies preliminary action by forming an upper-layer film with specific compositional properties before the lithography process. This pre-formed film acts as a buffer that maintains pattern integrity even when the immersion medium fails to follow lens movement at high scan speeds, preventing watermark defects while allowing high productivity
3Reliability
If a polymer with high fluorine atom content is used to increase water repellency, then hydrophobicity improves, but solubility in developer decreases leading to bridge defects
Solution Approach 1:
The patent precisely controls the fluorine atom content parameter within an optimal range (0.1-10% by mass) rather than maximizing it. This parameter optimization, combined with incorporating other functional groups (carboxyl, sulfonic acid), achieves the necessary water repellency while preserving sufficient developer solubility to prevent bridge defects
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 forms a liquid immersion lithography upper-layer film with moderate water repellency and high solubility, suppressing defects such as watermark and bridge defects, ensuring high-resolution patterns and improved production efficiency.
Implementation Method 1
a liquid immersion lithography upper-layer film-forming composition that contains a polymer that exhibits high water repellency (hydrophobicity)
Implementation Method 2
a liquid immersion lithography upper-layer film-forming composition includes (A) a polymer that includes a structural unit (I) shown by a formula (1), and (S) a solvent
Data Source
AI summary
A liquid immersion lithography upper-layer film-forming composition includes (A) a polymer that includes a structural unit (I) shown by the following formula (1), and (S) a solvent. R1 in the formula (1) represents a hydrogen atom, a methyl group, or a trifluoromethyl group. The polymer (A) preferably further includes a structural unit (II) that includes a sulfo group. The polymer (A) preferably further includes a structural unit (III) shown by the following formula (3). R2 in the formula (3) represents a hydrogen atom, a methyl group, or a trifluoromethyl group. R3 represents a linear or branched monovalent hydrocarbon group having 1 to 12 carbon atoms or a monovalent alicyclic group having 3 to 20 carbon atoms, provided that at least one hydrogen atom of the hydrocarbon group or the alicyclic group is substituted with a fluorine atom.