Negative Resist Composition for Acid Diffusion Control in Lithography
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Solution Overview
Problem
Existing chemically amplified negative resist compositions used in advanced lithography processes, such as ArF excimer laser lithography, suffer from insufficient resolution, line edge roughness (LER), pattern fidelity, and dose margin, primarily due to uncontrolled acid diffusion.
Innovation Solution
A chemically amplified negative resist composition comprising an onium salt quencher with a specific anion forming a low-boiling-point conjugate acid, a base polymer with defined repeat units, and a photoacid generator, which controls acid diffusion and enhances resolution, LER, and dose margin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional chemically amplified negative resist compositions are used, then the resist can be processed in advanced lithography processes, but the resolution, line edge roughness, pattern fidelity, and dose margin are insufficient due to uncontrolled acid diffusion
Solution Approach 1:
A quencher compound is introduced as an intermediary substance between the photoacid generator and the polymer. This quencher selectively reacts with diffusing acid molecules, forming a complex that prevents uncontrolled acid diffusion while maintaining the desired chemical amplification effect. The quencher acts as a mediator that controls the interaction between acid and polymer, thereby improving resolution and pattern fidelity without requiring fundamental changes to the lithography process
2Manufacturing precision
If the acid diffusion is controlled to improve resolution, then the line edge roughness and pattern fidelity improve, but the resist composition becomes more complex
Solution Approach 1:
The patent optimizes specific parameters of the quencher compound, including its molecular weight (50-500), pKa value (3-7), and concentration relative to the photoacid generator (0.1-10 equivalents). By carefully controlling these parameters, the resist composition achieves effective acid diffusion control and improved line edge roughness while maintaining a practical and manageable formulation complexity
3Manufacturing precision
If a quencher is added to control acid diffusion, then the resolution and pattern fidelity improve, but the resist composition requires additional components
Solution Approach 1:
The quencher compound is designed to perform multiple functions simultaneously: it controls acid diffusion, maintains chemical amplification, and contributes to the overall stability of the resist composition. This multi-functionality reduces the need for additional separate components, as the single quencher compound addresses multiple performance requirements including resolution enhancement and pattern fidelity improvement
4Manufacturing precision
If conventional resist compositions are used, then the process is simpler, but the dose margin is insufficient for high-precision micropatterning
Solution Approach 1:
The quencher compound is pre-incorporated into the resist composition at optimized concentrations before the lithography process. This preliminary preparation ensures that acid diffusion is controlled from the moment of exposure, providing a buffer against dose variations and improving the dose margin. The pre-configured quencher system allows the resist to maintain high pattern fidelity even when exposure dose varies within a broader range
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 achieves high-resolution, high-fidelity resist patterns with improved LER and dose margin, suitable for EUV and EB lithography, particularly in micropatterning technologies.
Implementation Method 1
an acid generator which is decomposed to generate an acid upon exposure to light
Implementation Method 2
a crosslinker which causes the polymer to crosslink in the presence of the acid serving as a catalyst
Implementation Method 3
Most often a quencher is added for controlling the diffusion of the acid generated upon light exposure
Data Source
AI summary
A chemically amplified negative resist composition comprising (A) a quencher in the form of an onium salt containing an anion (Xq−) which forms a conjugate acid (XqH) having a boiling point of lower than 165° C. and a molecular weight of up to 150, (B) a base polymer, and (C) a photoacid generator exhibits a high resolution and forms a pattern of satisfactory profile with low LER, fidelity and improved dose margin.