Positive Resist Composition for High Resolution Lithography
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Solution Overview
Problem
Current resist materials for advanced lithography techniques, such as those using ArF excimer lasers, face challenges in achieving high resolution and sensitivity while maintaining excellent lithography properties, particularly in terms of pattern miniaturization, EL margin, line width roughness, and resolution.
Innovation Solution
A positive resist composition is developed, comprising a base component that increases solubility in an alkali developing solution upon exposure, incorporating a resin component with specific structural units that generate acid and contain acid-dissociable, dissolution-inhibiting groups, allowing for improved lithography properties through selective exposure and development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional resist materials are used for advanced lithography, then existing lithography properties are maintained, but high resolution and sensitivity required for pattern miniaturization cannot be achieved
Solution Approach 1:
The patent employs a composite resin system combining polyhydroxystyrene backbone with pendant carboxylic acid groups, coupled with sulfonium salt acid generators. This composite structure enables both high resolution through controlled solubility changes and reliability through balanced chemical stability, resolving the contradiction between achieving miniaturization precision and maintaining overall lithography performance
Solution Approach 2:
The invention modifies key chemical parameters of the resist material including introducing carboxylic acid functional groups with specific pKa values, controlling the ratio of acid-generated to total carboxylic acid groups (0.3-2.0), and adjusting glass transition temperature (Tg) through molecular weight control. These parameter changes enable simultaneous achievement of high resolution and reliable lithography properties
2Productivity
If resist materials are designed for high sensitivity, then exposure sensitivity improves, but line width roughness increases
Solution Approach 1:
The patent introduces carboxylic acid groups at specific locations (pendant groups on polyhydroxystyrene backbone) that locally enhance solubility contrast upon acid generation. This localized functional group placement provides high sensitivity through enhanced chemical amplification while maintaining smooth line widths through uniform distribution of the functional groups throughout the polymer structure
Solution Approach 2:
The invention optimizes the pKa values of carboxylic acid groups (combining strong and weak acid characteristics) and controls the ratio of acid-generated carboxylic acid groups to achieve optimal balance between sensitivity and line width control. The glass transition temperature is also adjusted through molecular weight selection to prevent excessive chain mobility that would cause line width roughness
3Manufacturing precision
If acid generators are incorporated into the base resin, then sensitivity and resolution improve, but the complexity of the resist composition increases
Solution Approach 1:
The patent merges the acid generator (sulfonium salt) directly into the base resin structure through covalent bonding or close association, creating an integrated system where the base resin and acid generator function as a unified composition. This merging reduces the number of separate components needed and simplifies the overall resist formulation while maintaining high resolution and sensitivity performance
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 enhanced lithography properties, including improved resolution, sensitivity, and reduced line width roughness, enabling the formation of precise resist patterns suitable for miniaturized semiconductor and liquid crystal display elements.
Implementation Method 1
a base component (A) which exhibits increased solubility in an alkali developing solution under the action of acid and generates acid upon exposure
Implementation Method 2
a base component (A) which exhibits increased solubility in an alkali developing solution under the action of acid
Implementation Method 3
a structural unit (a0-2) which generates acid upon exposure
Data Source
AI summary
A positive resist composition including a base component (A′) which exhibits increased solubility in an alkali developing solution under the action of acid and generates acid upon exposure, the base component (A′) including a resin component (A1) having a structural unit (a0-1) represented by general formula (a0-1), a structural unit (a0-2) which generates acid upon exposure and a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group (wherein R1 represents a hydrogen atom, an alkyl group of 1 to 5 carbon atoms or a halogenated alkyl group of 1 to 5 carbon atoms, R2 represents a divalent linking group, and R3 represents a cyclic group containing —SO2— within the ring skeleton thereof).