Alicyclic Polymer Resist for Liquid Immersion Lithography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current pattern-forming methods in lithography face challenges such as deterioration of resist films, contamination of lens surfaces, and regional changes in refractive index due to substance elution in liquid immersion lithography, which affect lithography characteristics and require improved etching resistance and resolving power.
Innovation Solution
A pattern-forming method using a radiation-sensitive resin composition with a polymer containing an acid-labile group and an alicyclic group that avoids dissociation from the molecular chain, combined with a developer solution containing at least 80% organic solvent, to enhance etching resistance and lithography characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If liquid immersion lithography is used to achieve high resolution, then resolving power is improved, but resist film deteriorates and lens surface contamination occurs due to substance elution
Solution Approach 1:
The invention extracts and removes the problematic carboxyl groups from the polymer structure by using a polymer lacking carboxyl groups (such as polymers with hydroxyl groups, ester groups, or amide groups instead). This extraction of the harmful functional group eliminates the source of elution that causes resist film deterioration and lens contamination, while maintaining the resolving power achieved through liquid immersion lithography
Solution Approach 2:
The invention changes the chemical parameter of the polymer by selecting polymers without carboxyl groups (changing from carboxyl-containing polymers to carboxyl-free polymers with alternative functional groups). This parameter change in the polymer chemistry prevents elution issues while maintaining the desired lithography performance
2Reliability
If polymer with acid-labile group is used to enable pattern formation, then lithography characteristics improve, but etching resistance deteriorates due to dissociation of the molecular chain
Solution Approach 1:
The invention applies local quality by having different parts of the polymer structure serve different functions: the acid-labile group (such as t-butyl group or trimethylsilyl group) provides the necessary lithography characteristics and pattern formation capability, while the main polymer backbone and other structural units maintain etching resistance. This local differentiation allows each part to optimize its specific function without compromising the other
Solution Approach 2:
The invention uses composite material structure by combining polymer units with acid-labile groups (for lithography performance) with other polymer units that provide etching resistance. The radiation-sensitive resin composition itself is a composite containing the polymer, radiation-sensitive acid generator, and other components, creating a material system where different components contribute different properties that together resolve the contradiction
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 method provides superior etching resistance and lithography characteristics, enabling the formation of patterns with improved sensitivity and resolving ability while preventing elution and contamination issues during liquid immersion lithography.
Implementation Method 1
a radiation-sensitive acid generator; Upon exposure, the acid generator produces acid
Implementation Method 2
a first structural unit having an acid-labile group; the alicyclic group is capable of avoiding dissociation from a molecular chain by an action of an acid
Data Source
AI summary
A pattern-forming method includes coating a radiation-sensitive resin composition on a substrate to provide a resist film. The resist film is exposed. The exposed resist film is developed. A developer solution used in developing the exposed resist film includes no less than 80% by mass of an organic solvent. The radiation-sensitive resin composition includes a first polymer and a radiation-sensitive acid generator. The first polymer includes a first structural unit having an acid-labile group and an alicyclic group. The alicyclic group is capable of avoiding dissociation from a molecular chain by an action of an acid.