Multiblock Copolymer Resist Additive for Immersion Lithography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In ArF immersion lithography, resist films are prone to deformation, swelling, and defects such as bubbles and watermarks due to acid or amine compounds dissolving in water, leading to pattern collapse and contamination of the projection lens.
Innovation Solution
A resist additive in the form of a multiblock copolymer with a hydrophobic group that improves the hydrophobicity of the resist film surface, preventing leaching in water during immersion lithography and converting to hydrophilicity via acid-induced deprotection reaction for easy developer washing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective film is formed on the resist film to prevent contact with water, then material leaching is prevented, but the film structure becomes more complex and light transmittance may be interrupted
Solution Approach 1:
The patent combines the protective film function and the resist film function into a single integrated composition. The copolymer containing hydrophobic groups serves both as the resist matrix and as the protective layer, eliminating the need for a separate protective film while maintaining material leaching prevention
Solution Approach 2:
The copolymer resin performs multiple functions simultaneously: it acts as the resist base polymer, provides hydrophobic protection against water during immersion lithography, and enables pattern formation through acid-induced deprotection. This multi-functionality eliminates the need for separate protective films
2Reliability
If the resist film surface is made hydrophobic to prevent material leaching in water, then immersion lithography stability is improved, but developer washing becomes difficult
Solution Approach 1:
The patent introduces dynamic hydrophobicity that changes based on the chemical environment. The copolymer contains acid-labile protecting groups that are removed during development, transforming the surface from hydrophobic (for water resistance) to hydrophilic (for developer washing), allowing the property to adapt to different process stages
Solution Approach 2:
The patent changes the hydrophobicity parameter of the resist film during the development process. Acid-induced deprotection reactions modify the chemical structure of the copolymer, converting hydrophobic groups to hydrophilic groups, thereby changing the surface property from water-repellent to developer-washable
3Reliability
If a separate protective film is used to prevent contact with water, then material dissolution is prevented, but light transmittance at exposure wavelength is reduced
Solution Approach 1:
The patent merges the protective function with the resist film itself, eliminating the need for a separate protective layer that would interfere with light transmission. The copolymer provides inherent hydrophobic protection while maintaining optical clarity
4Device complexity
If the resist film directly contacts water during immersion lithography, then the process is simple, but pattern deformation and defects occur due to material leaching
Solution Approach 1:
The patent applies preliminary protection by incorporating hydrophobic groups into the resist composition before exposure. This pre-established hydrophobic barrier prevents water from penetrating and dissolving acids or amines during immersion lithography, maintaining pattern integrity without complex additional 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 resist additive effectively prevents material leaching during immersion lithography and facilitates efficient development by converting the resist film surface from hydrophobic to hydrophilic, reducing defects and ensuring high-resolution pattern formation.
Implementation Method 1
improves hydrophobicity of the surface of a resist film to prevent materials from being leached from the resist film in water
Implementation Method 2
converted to have hydrophilicity by deprotection reaction during a development process
Data Source
AI summary
A resist additive represented by Formula 1 below and a resist composition including the additive are disclosed. The resist additive improves hydrophobicity of the surface of the resist film to prevent materials from being leached in water during exposure of immersion lithography and is converted to have hydrophilicity by deprotection reaction during development. As a result, a micropattern of a resist film with excellent sensitivity and high resolution is formed.In Formula 1, the substituents are defined as described in the specification.