Positive Resist Composition Reducing Line Edge Roughness
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Solution Overview
Problem
Conventional resist compositions used in lithography techniques suffer from line edge roughness (LER) issues, particularly in the miniaturization of semiconductor elements, which affects the formation of fine patterns and requires improved resolution and smoothness of side wall surfaces.
Innovation Solution
A positive resist composition incorporating a resin component with a structural unit containing an acetal-type acid-dissociable, dissolution-inhibiting group featuring a cyclopentyl group, which increases alkali solubility upon acid exposure, is developed, along with an acid-generator component to form a resist pattern with reduced LER.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If PHS-based resins are used as base resin for KrF excimer laser lithography, then transparency is improved, but resolution deteriorates when used with light of wavelength shorter than 248 nm
Solution Approach 1:
The patent changes the chemical composition parameters of the base resin by incorporating structural units with acid-dissociable dissolution-inhibiting groups that do not contain aromatic rings, thereby maintaining transparency while improving resolution for shorter wavelength light
Solution Approach 2:
The patent creates a composite resin structure combining multiple structural units including acid-dissociable dissolution-inhibiting groups, carboxyl groups, and hydroxyl groups to achieve both transparency and high resolution simultaneously
2Adaptability or versatility
If conventional resist composition is used for miniaturization, then existing process compatibility is maintained, but line edge roughness increases affecting fine pattern formation
Solution Approach 1:
The patent modifies the chemical structure parameters of the base resin by introducing specific structural units with acid-dissociable dissolution-inhibiting groups, which reduce line edge roughness while maintaining compatibility with existing lithography processes
Solution Approach 2:
The patent applies dissolution-inhibiting groups at specific locations within the resin structure to locally control solubility and reduce edge roughness without affecting overall process compatibility
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 effectively reduces line edge roughness, enhances resolution, and improves the depth of focus and exposure margin, enabling the formation of precise resist patterns suitable for advanced semiconductor and display element manufacturing.
Implementation Method 1
an acid generator component (B) which generates acid upon exposure
Implementation Method 2
a resin component (A) which exhibits increased alkali solubility under action of acid
Data Source
AI summary
A positive resist composition including a resin component (A) which exhibits increased alkali solubility under action of acid and an acid-generator component (B) which generates acid upon exposure,the resin component (A) including a structural unit (a1) represented by general formula (I) shown below:wherein R represents a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group; R1′ represents a hydrogen atom or a lower alkyl group; n represents an integer of 0 to 3; R1 represents a lower alkyl group, a fluorine atom, or a fluorinated lower alkyl group; and p represents an integer of 0 to 2.