Positive Resist Composition with Acid Labile Groups
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Solution Overview
Problem
Current positive resist compositions face challenges in achieving high sensitivity, resolution, and etching resistance, particularly in advanced lithography processes such as EUV and ArF immersion lithography, where pattern miniaturization and high energy beam exposure require improved sensitivity and etching resistance without compromising productivity.
Innovation Solution
A chemically amplified positive resist composition featuring a polymer with phenolic hydroxide groups substituted by acid labile groups, specifically fluorenyl or fluorenylmethyl groups, and incorporating repeating units like hydroxy styrene and hydroxy vinyl naphthalene, which enhance sensitivity, resolution, and etching resistance, along with an acid generator and organic solvent for improved alkaline-dissolution contrast and coating properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a higher acceleration voltage is used in EB lithography to improve resolution and size controlling, then the degree of resolution and contrast are improved, but the sensitivity of the resist decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the resist by introducing a polymer with phenolic hydroxide groups substituted by acid labile groups (formula 1). This chemical parameter change enables the resist to maintain high sensitivity even at higher acceleration voltages (10-100 keV), resolving the contradiction between resolution and sensitivity by modifying the resist's chemical response to electron beam exposure.
Solution Approach 2:
The patent creates a composite resist system combining the phenolic polymer base resin with acid labile groups and acid generators. This composite structure allows the resist to exhibit both high sensitivity (through acid-catalyzed dissolution) and high resolution (through controlled acid diffusion), enabling simultaneous improvement of both parameters that were previously contradictory.
2Manufacturing precision
If the resist film is made thinner to prevent pattern fall and improve resolution in EB lithography, then resolution is improved, but the dry-etching resistance of the resist decreases
Solution Approach 1:
The patent changes the chemical composition of the resist by incorporating phenolic hydroxide groups with acid labile substituents. This compositional change provides high etching resistance even in thinner film configurations, as the phenolic structure and acid labile groups work together to maintain film integrity during dry etching while enabling fine pattern resolution.
Solution Approach 2:
The composite resist system combines the phenolic polymer backbone with acid labile groups and crosslinkable functionalities. This composite structure provides both the thin-film capability for high resolution and the chemical resistance needed for dry etching, as the crosslinked network formed during processing enhances etching resistance without compromising pattern fidelity.
3Strength
If a novolak polymer is used to achieve good etching resistance in EB lithography, then etching resistance is improved, but it becomes difficult to control molecular weight and degree of dispersion
Solution Approach 1:
The patent changes the polymer structure from conventional novolak to a phenolic polymer with specifically designed acid labile substituent groups (formula 1). This structural modification maintains the etching resistance of novolak polymers while enabling better molecular weight and dispersion control through controlled polymerization of the defined monomer units.
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, resolution, and excellent etching resistance, suitable for VLSI manufacturing and micropatterning, with improved alkaline-dissolution contrast and reduced acid diffusion, leading to precise pattern formation and enhanced process applicability.
Implementation Method 1
a polymer whose hydrogen atom of a phenolic hydroxide group is substituted by an acid labile group represented by the following general formula (1)... a chemically amplified positive resist composition
Implementation Method 2
In a high energy beam of an extremely short wavelength such as an EB, a X-ray, and the like, a light element such as a hydrocarbon used in a resist has almost no absorption
Implementation Method 3
In a high energy beam of an extremely short wavelength such as an EB, a X-ray, and the like, a light element such as a hydrocarbon used in a resist has almost no absorption
Implementation Method 4
it is necessary to improve a dry-etching resistance of a resist... a polymer whose hydrogen atom of a phenolic hydroxide group is substituted by an acid labile group... excellent etching resistance
Implementation Method 5
a chemically amplified positive resist composition... incorporating repeating units like hydroxy styrene and hydroxy vinyl naphthalene, which enhance sensitivity, resolution, and etching resistance, along with an acid generator
Data Source
AI summary
The present invention provides a polymer, having a high sensitivity, a high degree of resolution, a good pattern configuration after exposure, and in addition an excellent etching resistance, suitable as a base resin for a positive resist composition, especially for a chemically amplified positive resist composition; a positive resist composition using the polymer; and a patterning process.The positive resist composition of the present invention is characterized in that it contains at least, as a base resin, a polymer whose hydrogen atom of a phenolic hydroxide group is substituted by an acid labile group represented by the following general formula (1).