Sulfonium Compound Resist Composition for ArF Lithography
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Solution Overview
Problem
Current resist materials for ArF lithography face challenges in achieving high resolution and minimizing line width roughness (LWR) and mask error factor (MEF) due to acid diffusion, leading to pattern collapse and degradation of contrast and critical dimension uniformity.
Innovation Solution
A resist composition incorporating a sulfonium compound with a specific structure, combined with an organic solvent, a polymer containing acid labile groups, and a photoacid generator, which effectively controls acid diffusion and enhances pattern formation during DUV, EUV, and EB lithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If amine compounds are used as acid diffusion inhibitors, then LWR is improved, but contrast and MEF deteriorate
Solution Approach 1:
The invention changes the chemical parameters of the acid diffusion inhibitor by using sulfonium salts with specific structures (formula 1) instead of conventional amine compounds. This parameter change enables simultaneous improvement in LWR, contrast, and MEF by optimizing the molecular structure with specific R1, R2, R3 groups and p, q, r values that control acid diffusion while maintaining high contrast.
Solution Approach 2:
The invention creates a composite resist composition system combining the specific sulfonium compound (formula 1) with a polymer having acid-labile groups (formula 2) and a photoacid generator (formula 3). This composite material approach allows the sulfonium salt to function as an acid diffusion inhibitor while the polymer provides contrast through acid-labile group cleavage, resolving the contradiction between LWR improvement and contrast maintenance.
2Manufacturing precision
If acid diffusion is reduced to improve resolution, then pattern collapse resistance improves, but manufacturing complexity increases
Solution Approach 1:
The invention simplifies the resist composition by optimizing the sulfonium salt structure parameters (R1, R2, R3 groups and p, q, r values) to provide effective acid diffusion inhibition at low concentrations. This parameter optimization reduces the need for multiple additive components, thereby reducing manufacturing complexity while maintaining high resolution and pattern collapse resistance.
3Manufacturing precision
If the pattern size is reduced to achieve finer features, then manufacturing precision improves, but acid diffusion becomes more detrimental
Solution Approach 1:
The sulfonium salt with specific structure (formula 1) provides localized acid diffusion inhibition precisely where needed in the resist composition. The molecular structure with specific R1, R2, R3 groups and p, q, r values creates a localized effect that controls acid diffusion at the molecular level, enabling fine pattern formation without the harmful effects of acid diffusion that plague conventional systems.
4Illumination intensity
If conventional resist materials are used for ArF lithography, then transparency is improved, but LWR and MEF deteriorate due to acid diffusion
Solution Approach 1:
The invention creates a composite resist system where the sulfonium compound (formula 1) serves as an acid diffusion inhibitor that is transparent at 193 nm, the polymer (formula 2) provides contrast through acid-labile groups, and the photoacid generator (formula 3) generates acid upon exposure. This composite material approach maintains the transparency required for ArF lithography while eliminating the LWR and MEF problems caused by acid diffusion in conventional materials.
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 sulfonium compound improves LWR, MEF, and collapse resistance, resulting in high accuracy micropatterning with improved resolution and contrast, addressing the limitations of existing acid diffusion inhibitors.
Implementation Method 1
the influence of acid diffusion is detrimental to lithography performance
Implementation Method 2
a photoacid generator
Data Source
AI summary
A sulfonium compound having formula (1) is provided wherein R1, R2 and R3 are a C1-C20 monovalent hydrocarbon group which may contain a heteroatom, p=0-5, q=0-5, and r=0-4. A resist composition comprising the sulfonium compound is processed by lithography to form a resist pattern with improved LWR and pattern collapse.