Morpholino Quencher Resist Composition for Dimensional Stability
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Solution Overview
Problem
Current chemically amplified resist compositions face challenges in maintaining high dissolution contrast and reducing edge roughness (LWR) at room temperature, particularly in negative tone pattern formation, where acid diffusion leads to dimensional changes over time due to post-exposure bake delays.
Innovation Solution
Incorporating a sulfonium or iodonium salt with a morpholino group as a quencher in the resist composition, which suppresses acid diffusion at room temperature, thereby maintaining high dissolution contrast and reducing LWR, and ensuring no dimensional changes during pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional quenchers (amines, sulfonium/iodonium salts of non-fluorinated sulfonic acid or carboxylic acid) are used, then acid diffusion is suppressed to some extent, but dissolution contrast is insufficient and edge roughness (LWR) is high at room temperature
Solution Approach 1:
The patent changes the chemical structure of the quencher by introducing a morpholino group with specific substituents (R1-R6 as defined in the claims) to alter its acid diffusion control properties. This structural parameter change enables the quencher to effectively suppress acid diffusion at room temperature while maintaining high dissolution contrast, resolving the contradiction between manufacturing precision and reliability.
Solution Approach 2:
The patent uses a composite quencher system combining sulfonium or iodonium salt with a morpholino group containing specific substituents. This composite structure integrates the acid-generating capability of onium salts with the diffusion-control properties of the morpholino group, achieving both high dissolution contrast and reliable acid diffusion suppression simultaneously.
2Manufacturing precision
If acid amplifying mechanism is used, then contrast is enhanced, but environmental resistance is degraded by amine contamination and maximum resolution is reduced by increased acid diffusion distance
Solution Approach 1:
The patent extracts the harmful amine contamination component from the acid amplifying system by using alternative quenchers (sulfonium/iodonium salts of fluorinated sulfonic acid or carboxylic acid with morpholino group) that do not rely on amine-based acid amplification. This eliminates the source of environmental resistance degradation while maintaining the desired contrast enhancement through a different chemical mechanism.
Solution Approach 2:
The patent introduces a morpholino group-containing quencher as an intermediary substance that mediates between the acid generator and the resist film. This intermediary suppresses acid diffusion to unexposed areas without requiring amine contamination, thereby maintaining environmental resistance while achieving the necessary contrast for high-resolution patterning.
3Manufacturing precision
If post-exposure bake is applied to enhance contrast, then dissolution contrast is improved, but dimensional changes occur over time due to acid diffusion
Solution Approach 1:
The patent applies preliminary action by incorporating the morpholino group-containing quencher into the resist composition before exposure. This pre-loaded quencher actively suppresses acid diffusion during and after exposure, preventing dimensional changes that would otherwise occur during post-exposure bake or storage. The preliminary presence of the quencher eliminates the need for aggressive post-exposure processing that would cause dimensional instability.
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 composition with the sulfonium or iodonium salt of sulfonic acid containing a morpholino group achieves improved resolution, focus margin, and reduced LWR, maintaining pattern integrity regardless of tone, whether positive or negative, and withstands alkaline or organic solvent development.
Implementation Method 1
If a sulfonium or iodonium salt capable of generating an α-fluorinated sulfonic acid is combined with a sulfonium or iodonium salt capable of generating an α-non-fluorinated sulfonic acid, the sulfonium or iodonium salt capable of generating an α-non-fluorinated sulfonic acid undergoes ion exchange with the α-fluorinated sulfonic acid.
Data Source
AI summary
A resist composition comprising a base polymer and a sulfonium or iodonium salt of sulfonic acid containing a morpholino group offers dimensional stability on PPD and a satisfactory resolution.