Chemically Amplified Resist Composition for EUV Lithography
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Solution Overview
Problem
Conventional chemically amplified negative resist compositions fail to effectively reduce line edge roughness (LER) and minimize substrate poisoning when forming ultrafine patterns, particularly with feature sizes of 0.1 µm or less, and exhibit issues like bridge formation and undercut problems during EB or EUV lithography.
Innovation Solution
A chemically amplified negative resist composition is developed, incorporating a basic polymer with secondary or tertiary amine structures as a side chain, which reduces LER and substrate poisoning. The composition includes an alkali-soluble polymer, an acid generator, and a nitrogen-containing compound, with optional crosslinkers, designed to improve etch resistance and adhesion to the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional chemically amplified negative resist compositions are used, then the basic resist function is achieved, but line edge roughness increases and substrate poisoning occurs during ultrafine pattern formation
Solution Approach 1:
The patent changes the chemical parameters of the basic compound by incorporating secondary or tertiary amine structures directly into the polymer side chains. This structural modification alters the basic compound's molecular weight, distribution uniformity, and chemical reactivity, thereby reducing acid diffusion control issues that cause LER and substrate poisoning while maintaining the essential basic function.
Solution Approach 2:
The patent creates a composite polymer structure where the base polymer is combined with side chains containing secondary or tertiary amine groups. This composite approach integrates the basic compound functionality directly into the polymer matrix, achieving uniform distribution and preventing the harmful effects of conventional separate basic compound additions.
2Length of moving object
If the resist film is thinned to achieve smaller pattern features, then the pattern feature size is reduced, but etch resistance decreases
Solution Approach 1:
The patent modifies the chemical composition parameters of the resist by incorporating specific secondary or tertiary amine structures in controlled amounts (0.1-10 mol% of total structural units). This chemical parameter change enhances the resist's etch resistance through improved crosslinking density and chemical stability, allowing thin films to maintain sufficient mechanical and chemical strength despite reduced thickness.
3Manufacturing precision
If a basic compound is added to control acid diffusion, then the resolution is improved, but the compound migrates and diffuses to the water phase, altering the resist surface region
Solution Approach 1:
The patent merges the basic compound functionality with the polymer structure itself by incorporating secondary or tertiary amine groups as side chains. This combination eliminates the need for separate basic compound additions and prevents migration to the water phase, as the basic groups are covalently bound to the polymer matrix and remain uniformly distributed throughout the resist film.
Solution Approach 2:
The polymer backbone acts as an intermediary that anchors the basic amine groups in place. Instead of adding free basic compounds that can migrate, the polymer structure serves as a stable carrier, maintaining the basic groups' positions and preventing their diffusion to the aqueous phase while still providing acid diffusion control.
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 achieves improved LER and reduced undercut, enabling the formation of high-resolution, ultrafine patterns with enhanced etch resistance and minimal substrate interaction, effectively addressing the limitations of conventional resist compositions.
Implementation Method 1
an acid generator which is decomposed to generate an acid upon exposure to light
Implementation Method 2
a basic polymer for controlling the diffusion of the acid generated upon light exposure
Data Source
AI summary
A chemically amplified negative resist composition is provided comprising (A) an alkali-soluble polymer, (B) an acid generator, and (C) a nitrogen-containing compound as a basic component, the polymer (A) turning alkali insoluble under the catalysis of acid. A basic polymer having a secondary or tertiary amine structure on a side chain serves as components (A) and (C). Processing the negative resist composition by EB or EUV lithography process may form a fine size resist pattern with advantages including uniform diffusion of base, improved LER, controlled deactivation of acid at the substrate interface, and a reduced degree of undercut.