Acrylate Ester Resist Composition for ArF Lithography
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Solution Overview
Problem
Current chemically amplified resists using benzene rings are not transparent enough for ArF excimer lasers, leading to surface roughness and line edge roughness issues in semiconductor production, especially at high resolution requirements below 150 nm, and line slimming occurs during electron beam exposure.
Innovation Solution
A chemically amplified positive type resist composition using a resin component with only acrylate ester units, an acid generator, and an organic solvent, where the resin component is a copolymer with structural units derived from acrylate esters containing polycyclic groups that increase solubility and Tg value, allowing for improved resist pattern formation at lower temperatures and reduced surface roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If benzene ring-containing resins (polyhydroxystyrene) are used for KrF excimer laser (248 nm) processes, then high transparency is achieved, but insufficient transparency occurs for ArF excimer laser (193 nm) processes
Solution Approach 1:
The patent changes the chemical structure parameters of the resin by replacing benzene rings with adamantane rings and other aliphatic cyclic structures. This structural parameter change maintains the protective group functionality while improving transparency to ArF excimer laser radiation at 193 nm, resolving the contradiction between transparency and performance reliability.
Solution Approach 2:
The patent employs composite resin systems combining multiple components: adamantane-containing polymers, carboxylic acid generators, and specific protective groups. This composite approach allows optimization of both transparency and chemical amplification performance for ArF excimer laser processes.
2Ease of manufacture
If acrylate ester resin with low Tg value is used, then ease of manufacture is improved, but resist pattern formation becomes impossible at conventional processing temperatures
Solution Approach 1:
The patent modifies the thermal parameters of the acrylate ester resin by incorporating specific molecular structures that raise the Tg value to 100-150°C. This parameter change enables the resin to maintain structural integrity during processing while retaining the manufacturing advantages of acrylate ester chemistry.
3Productivity
If conventional etching processes are used with existing resist patterns, then etching capability is achieved, but surface roughness and line edge roughness appear on the resist film
Solution Approach 1:
The patent incorporates cushioning measures by designing a resist formulation with optimized glass transition temperature and chemical stability that prevents surface roughness formation before etching occurs. The specific resin composition acts as a protective buffer that maintains surface integrity during the etching process.
4Measurement precision
If high resolution patterns (no more than 150 nm) are required, then design rule compliance is improved, but line edge roughness and distortions become more problematic
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: resin molecular weight, glass transition temperature, protective group stability, and acid generator selection. These coordinated parameter changes enable high resolution patterning below 150 nm while maintaining smooth line edges and minimizing roughness effects.
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 high sensitivity and resolution with low surface roughness and line edge roughness, and minimizes line slimming, enabling the formation of finely detailed patterns suitable for advanced semiconductor production.
Implementation Method 1
a chemically amplified positive type resist composition which displays excellent sensitivity and resolution, and enables the formation of a finely detailed resist pattern with low levels of surface roughness on etching, line edge roughness and line slimming
Implementation Method 2
practical applications also utilize materials with methacrylic acid in the principal chain. The reason for this observation is that a resin with a conventional acrylate ester as the principal chain (hereafter, simply referred to as an acrylate ester resin), as disclosed in the above publications, displays a lower Tg value than a resin with a methacrylate ester as the principal chain (hereafter, simply referred to as a methacrylate ester resin)
Data Source
AI summary
There is provided a positive type resist composition comprising (A) a resin component with only units derived from an acrylate ester in the principal chain, for which the solubility in alkali increases under the action of acid, (B) an acid generator component which generates acid on exposure, and (C) an organic solvent component, wherein the resin component (A) is a copolymer comprising (a1) a structural unit derived from an acrylate ester comprising, as an acid dissociable dissolution inhibiting group on a side chain, a polycyclic dissolution inhibiting group which is eliminated more easily than a 2-methyl-2-adamantyl group, (a2) a structural unit derived from an acrylate ester comprising a lactone containing polycyclic group on a side chain, and (a3) a structural unit derived from an acrylate ester comprising a hydroxyl group containing polycyclic group on a side chain; as well as a resist pattern formation method using such a composition.