Positive Resist Composition Defect Reduction via Copolymer Design
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Solution Overview
Problem
Conventional resist compositions fail to achieve both reduced defects and excellent lithography characteristics, particularly when forming fine resist patterns with short wavelength light sources like ArF excimer lasers, EUV, or EB, as they often compromise on either defect reduction or lithography performance.
Innovation Solution
A positive resist composition comprising a resin component with specific structural units that increase alkali solubility upon acid exposure, combined with an acid generator, allowing for improved alkali solubility and reduced defects while maintaining excellent lithography characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the hydrophilicity of the base resin is increased to reduce defects, then the level of defects is reduced, but the lithography characteristics deteriorate
Solution Approach 1:
The patent applies local quality by creating a resin composition where only specific functional units (a1, a2, a3) within the copolymer structure provide defect-reducing hydrophilicity, while other units maintain lithography performance. This localized functional distribution allows different regions of the resin molecule to serve different purposes: units a1-a3 suppress defects locally without compromising overall lithography characteristics
Solution Approach 2:
The patent uses composite materials by combining multiple copolymers with different functions: copolymer (A1) containing structural units (a1), (a2), and (a3) that reduce defects, and copolymer (A2) that maintains lithography characteristics. This composite resin system achieves both defect reduction and excellent lithography performance by synergistic combination of materials with complementary properties
2Ease of manufacture
If conventional resist compositions are used, then manufacturing process is simple, but both defect reduction and lithography characteristics cannot be achieved simultaneously
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compositional parameters of the copolymer: structural unit (a1) at 5-50 mol%, structural unit (a2) at 10-60 mol%, and structural unit (a3) at 5-50 mol%. By optimizing these molecular composition parameters, the resin achieves both defect reduction and excellent lithography characteristics while maintaining compatibility with conventional resist formulation and processing
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 composition effectively reduces defects and enhances lithography characteristics, such as resolution and depth of focus, by using a copolymer with structural units that include acid-dissociable groups and lactone-containing monocyclic groups, achieving superior pattern formation with reduced surface abnormalities.
Implementation Method 1
an acid generator that generates acid upon exposure
Implementation Method 2
a copolymer (A1) that includes a structural unit (a1) derived from an acrylate ester that contains an acid-dissociable, dissolution-inhibiting group
Data Source
AI summary
A positive resist composition includes a resin component (A) that exhibits increased alkali solubility under the action of acid, and an acid generator component (B) that generates acid upon exposure, wherein the resin component (A) is a mixture of a copolymer (A1) that includes a structural unit (a1) derived from an acrylate ester that contains an acid-dissociable, dissolution-inhibiting group, a structural unit (a2) derived from a methacrylate ester that contains a lactone-containing monocyclic group, and a structural unit (a3) derived from an acrylate ester that contains a polar group-containing polycyclic group, and a copolymer (A2) that has a different structure from the copolymer (A1) and has a lower hydrophilicity than the copolymer (A1).