Chemically Amplified Resist Composition for EUV Patterning
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Solution Overview
Problem
Current chemically amplified resist compositions face challenges in achieving high sensitivity, contrast, and etch resistance while maintaining improved line width roughness (LWR) and critical dimension uniformity (CDU) for pattern formation, especially in photolithography using EB or EUV with feature sizes below 0.2 μm.
Innovation Solution
A chemically amplified resist composition is developed, comprising a polymer with repeat units containing an acid labile group with an aromatic triple bond and phenolic hydroxy groups, combined with a specific photoacid generator, which enhances solubility in alkaline solutions and reduces acid diffusion, leading to improved pattern formation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acetal and similar protective groups requiring relatively small activation energy for deprotection are used, then resist sensitivity is improved, but deprotection reaction takes place in unexposed regions causing degradation of edge roughness and loss of dimensional uniformity
Solution Approach 1:
The patent changes the chemical parameter of the protective group from acetal (low activation energy) to aromatic triple bond-containing groups (high activation energy). This parameter change allows the system to achieve high sensitivity through high contrast while preventing premature deprotection in unexposed regions, thereby resolving the contradiction between sensitivity and pattern quality.
Solution Approach 2:
The patent employs a composite approach by combining multiple protective groups (aromatic triple bond-containing groups and other acid-labile groups) within the same resist composition. This composite strategy enables simultaneous achievement of high sensitivity and maintained pattern quality by leveraging the high activation energy characteristic of aromatic triple bonds to prevent unwanted deprotection.
2Manufacturing precision
If high-energy radiation such as UV, deep UV or EB is used as energy source for exposure, then pattern formation at small feature size is achieved, but substantial absorption of light near to wavelength 200 nm occurs
Solution Approach 1:
The patent converts the harmful effect of light absorption near 200 nm into a beneficial feature by utilizing this absorption characteristic to enhance the photoacid generator's effectiveness. The absorbed energy is harnessed to generate photoacids that catalyze the deprotection reaction, thereby transforming the energy loss into a useful function for achieving high-resolution patterning.
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 exhibits high sensitivity, contrast, and etch resistance with reduced LWR and CDU, suitable for fine pattern formation in photolithography, particularly effective for feature sizes below 0.2 μm.
Implementation Method 1
a photoacid generator which generates an acid under the action of high-energy radiation
Implementation Method 2
Under the catalysis of an acid generated from the photoacid generator upon exposure to high-energy radiation, the protective group is deprotected so that the polymer may become solubilized in alkaline developer
Implementation Method 3
a polymer adapted to increase its solubility in an aqueous alkaline under the action of an acid
Data Source
AI summary
A chemically amplified resist composition is provided comprising (A) a polymer adapted to increase its solubility in an aqueous alkaline under the action of an acid, the polymer comprising repeat units, represented by the formula (A1), and repeat units, represented by the formula (B1), and lacking repeat units adapted to generate an acid upon exposure, and (B) a photoacid generator represented by the formula (PAG-a) or (PAG-b) which generates an acid under the action of KrF excimer laser, ArF excimer laser, electron beams or extreme ultraviolet radiation.