Fluorinated Resist Compounds for Immersion Lithography Water Tracking
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Solution Overview
Problem
Current resist materials for immersion lithography face challenges in achieving both excellent lithography properties and hydrophobicity, which is essential for effective water tracking in scanning-type immersion exposure systems, as high hydrophobicity can deteriorate lithography properties like resolution and sensitivity.
Innovation Solution
A novel compound and polymeric compound with specific structural units, represented by general formulas (I) and (II), are introduced, which enhance the hydrophobicity of the resist film while maintaining or improving lithography properties by incorporating fluorinated alkyl groups and cyclic structures, allowing for better water tracking and reduced substance elution during immersion exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If hydrophobicity of the resist film is increased to improve water tracking ability, then water tracking ability is improved, but lithography properties such as resolution and sensitivity are deteriorated
Solution Approach 1:
The patent introduces a specific hydrophobic group (formula (1)) with a defined molecular structure containing fluorinated alkyl chains and cyclic hydrocarbon groups. By controlling the parameters of this hydrophobic group (such as the number of carbon atoms in the alkyl chain and the type of cyclic hydrocarbon), the patent achieves optimal balance between water tracking ability and lithography properties. The hydrophobic group is incorporated into the base resin at controlled amounts (0.1-10 mass%), allowing precise adjustment of hydrophobicity without excessive impact on resolution and sensitivity.
Solution Approach 2:
The patent creates a composite resist system by combining a base resin containing the specific hydrophobic group (formula (1)) with a chemically amplified resist system including acid generator and base resin. This composite approach allows the hydrophobic group to provide water tracking ability while the chemically amplified resist components maintain lithography properties. The synergistic combination resolves the contradiction by distributing functions across different material components.
2Ease of operation
If hydrophobicity of the resist film is increased to improve water tracking ability, then water tracking ability is improved, but substance elution increases
Solution Approach 1:
The patent optimizes the molecular structure parameters of the hydrophobic group (formula (1)) to achieve sufficient hydrophobicity for water tracking while minimizing substance elution. The specific structure with fluorinated alkyl chains and cyclic hydrocarbon groups provides strong hydrophobic interaction with water without excessive solubility in the developing solution. The amount of hydrophobic group is controlled within 0.1-10 mass% to balance these competing requirements.
3Manufacturing precision
If conventional resist materials are used for immersion lithography, then lithography properties are maintained, but water tracking ability is insufficient
Solution Approach 1:
The patent introduces a localized hydrophobic group (formula (1)) into the resist film structure. This hydrophobic group is specifically positioned within the base resin molecular structure to provide water tracking ability at the film-water interface, while the rest of the resist material maintains its lithography properties. The hydrophobic character is concentrated in specific molecular regions rather than uniformly distributed, allowing selective improvement of water tracking without compromising overall lithography performance.
Data Source
AI summary
A compound represented by general formula (I); and a polymeric compound including a structural unit (a1) represented by general formula (II).wherein R represents a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group; each of R1 to R3 independently represents an alkyl group or a fluorinated alkyl group, with the provision that no fluorine atom is bonded to a carbon atom adjacent to the tertiary carbon atom to which R1 to R3 are bonded, and at least one of R1 to R3 represents a fluorinated alkyl group; and R2 and R3 may form a ring structure.