Fluorine-Containing Polymer Resist Suppresses Acid Elution
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Solution Overview
Problem
In microfabrication processes, particularly in liquid immersion lithography, there is a challenge in preventing acid generator elution from the resist film into the immersion medium, which can lead to contamination and decreased film performance, and in achieving high-speed scan exposure while maintaining the integrity of the resist pattern.
Innovation Solution
A radiation-sensitive resin composition is developed, comprising a polymer with a fluorine-containing group, a photoacid generator, and a polymer with lower fluorine content, which includes an acid-labile group. This composition ensures high hydrophobicity and uneven distribution of the fluorine-containing polymer on the film surface, enhancing the dynamic contact angle and solubility in alkaline developers, thereby reducing acid generator elution and improving draining capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fluorine-containing polymer is added to improve hydrophobicity and suppress acid generator elution, then the elution of acid generator is suppressed, but the device complexity increases due to additional components
Solution Approach 1:
The patent combines multiple functions into a single fluorine-containing polymer component. This polymer simultaneously provides hydrophobicity to suppress acid generator elution, enhances draining capability through uneven surface distribution, and contributes to pattern fidelity. By merging these functions into one component rather than using separate additives, the invention reduces overall system complexity while achieving multiple benefits.
Solution Approach 2:
The fluorine-containing polymer serves multiple functions within the resist composition: (1) it suppresses acid generator elution into the immersion medium, (2) it enhances the draining capability of the resist film surface, and (3) it improves pattern fidelity. This multi-functionality allows a single component to address several technical challenges, reducing the need for multiple separate additives and simplifying the overall composition.
2Stability of the object's composition
If the fluorine-containing polymer is uniformly distributed in the resist film, then the hydrophobicity is evenly distributed, but the draining capability is insufficient due to lack of surface unevenness
Solution Approach 1:
The invention creates local variations in fluorine-containing polymer concentration at the resist film surface through controlled application and drying processes. This results in uneven distribution of hydrophobic properties at the surface level, which enhances draining capability by creating preferential pathways for water removal, while the bulk composition remains uniformly distributed to maintain overall hydrophobicity.
Solution Approach 2:
The distribution of fluorine-containing polymer at the surface is made dynamic through the drying process. During drying, the polymer migrates and redistributes based on evaporation rates and surface tension gradients, creating an uneven surface distribution that enhances draining capability. This dynamic redistribution occurs automatically during the standard resist film formation process without requiring additional steps.
3Manufacturing precision
If liquid immersion lithography is used to achieve high resolution, then the resolution is improved, but the acid generator elutes into the immersion medium causing contamination
Solution Approach 1:
The fluorine-containing polymer acts as an intermediary barrier between the acid generator and the immersion medium. It creates a hydrophobic interface that prevents direct contact and interaction between the acid generator and water-based immersion medium, thereby suppressing elution and contamination while allowing the liquid immersion lithography process to proceed for high-resolution patterning.
Solution Approach 2:
The invention converts the potential harm of acid generator elution into a benefit by using the fluorine-containing polymer to create a hydrophobic barrier. This barrier not only prevents contamination but also enhances the draining capability and improves pattern fidelity. The same hydrophobic property that could potentially cause adhesion issues is converted into a benefit for suppressing elution and enhancing drainage.
4Productivity
If the hydrophobicity of the resist film surface is increased to improve draining capability, then the draining capability is improved, but the solubility in alkaline developer decreases
Solution Approach 1:
The invention carefully controls the fluorine atom content and molecular weight of the fluorine-containing polymer to optimize the balance between hydrophobicity and solubility. By adjusting these parameters, the polymer provides sufficient hydrophobicity for enhanced draining capability while maintaining adequate solubility in alkaline developer for proper pattern development. The fluorine atom content is specifically controlled within certain ranges to achieve this balance.
Data Source
AI summary
A radiation-sensitive resin composition includes (A) a polymer that includes a structural unit (I) including a group shown by the following formula (i), (B) a photoacid generator, and (C) a polymer that has a fluorine atom content lower than that of the polymer (A), and includes an acid-labile group. The polymer (A) preferably includes a structural unit shown by the following formula (1) as the structural unit (I). It is preferable that X in the formula (1) represent a divalent or trivalent chain-like hydrocarbon group or alicyclic hydrocarbon group.