Low Polydispersity Fluorinated Resin for Immersion Lithography
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Solution Overview
Problem
In immersion lithography, the migration of resist components into the immersion liquid during exposure leads to contamination and coating defects, and the addition of high molecular weight components can cause phase separation and degrade coating properties.
Innovation Solution
A resin with a peak area of high molecular weight components less than 0.1% is synthesized using radical polymerization, incorporating a fluorinated alcohol group and other specific structures to hydrophobilize the surface and prevent component migration, combined with a positive resist composition containing a monocyclic or polycyclic alicyclic hydrocarbon structure and a compound generating acid upon irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin with high molecular weight components is added to the resist layer to hydrophobilize the surface, then the followability of immersion liquid is improved, but phase separation occurs at the surface layer formation and coating property is degraded
Solution Approach 1:
The invention changes the molecular weight parameter of the resin by controlling the weight average molecular weight to be 1,000 to 100,000 and the polydispersity index to be 1.05 or less. This parameter control prevents phase separation while maintaining hydrophobicity, resolving the contradiction between coating quality and liquid followability.
Solution Approach 2:
The invention creates a surface layer with specific properties by controlling resin molecular weight distribution. The surface layer formed has appropriate hydrophobicity without phase separation, achieving local quality improvement at the resist surface while maintaining overall coating integrity.
2Object-generated harmful factors
If a resin with high molecular weight components is added to the resist layer to prevent dissolution of resist components, then contamination is reduced, but development defect occurs due to insolubility in alkali
Solution Approach 1:
The invention optimizes the molecular weight parameters (weight average molecular weight of 1,000 to 100,000 and polydispersity index of 1.05 or less) to ensure the resin remains soluble in alkali developers while preventing resist component dissolution. This parameter control resolves the contradiction between preventing contamination and avoiding development defects.
3Object-generated harmful factors
If the molecular weight of resin components is increased to improve hydrophobicity, then component migration is prevented, but coating uniformity is degraded due to phase separation
Solution Approach 1:
The invention controls the molecular weight distribution parameters (weight average molecular weight and polydispersity index) to achieve optimal hydrophobicity without phase separation. This ensures coating uniformity while preventing component migration, resolving the contradiction between migration prevention and coating stability.
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 resin effectively hydrophobilizes the resist film surface, improving followability and preventing coating and development defects, while maintaining solubility in alkali developers for improved patterning performance.
Implementation Method 1
the addition of a hydrophobic resin to the resist layer not only can prevent the dissolution of resist component but also can hydrophobilize the surface layer so that a receding contact angle of the surface of resist layer against water can be increased
Implementation Method 2
a compound which generates an acid upon irradiation of an actinic ray or radiation
Data Source
AI summary
A resin is to be added to a resist composition and localized on a surface of a resist film so as to hydrophobilize the surface of a resist film and has a peak area of a high molecular weight component having a molecular weight of 30,000 or more is 0.1% or less of a total peak area in a molecular weight distribution measured by gel permeation chromatography.