Molecular Resist Composition for EUV Lithography
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Solution Overview
Problem
Current EUV lithography technologies face challenges in achieving high sensitivity, resolution, and low line width roughness (LWR) due to the limitations of molecular resist compositions, particularly with the influence of shot noise and poor performance of inorganic resist compositions in terms of solubility and stability.
Innovation Solution
A molecular resist composition comprising an onium salt with a cyclic ether site, such as a sulfonium salt, is developed, which improves sensitivity and resolution when processed by high-energy radiation like EB or EUV lithography, and includes an organic solvent and optional amine compounds or surfactants to enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If polymeric resist composition is used in EUV lithography, then sensitivity is improved, but pattern surface roughening occurs and pattern control becomes difficult
Solution Approach 1:
The patent segments the resist composition into low-molecular-weight components instead of using high-molecular-weight polymers. This segmentation reduces the molecular size from polymer level to small molecule level, which minimizes acid diffusion and prevents pattern surface roughening while maintaining sensitivity through optimized molecular structure design.
Solution Approach 2:
The patent changes the molecular weight parameter from high (polymer) to low (small molecule), and adjusts the chemical structure parameters to include specific acid generators and base compounds. This parameter transformation enables the resist to achieve both high sensitivity and low roughness by controlling acid diffusion at the molecular level.
2Manufacturing precision
If molecular resist composition with low-molecular-weight materials is used, then pattern surface roughness is improved, but acid diffusion control becomes difficult
Solution Approach 1:
The patent introduces a base compound as an intermediary substance that interacts with the acid generator and photoacid. This base compound acts as a mediator to control acid diffusion and neutralization, enabling precise pattern formation while maintaining the benefits of low-molecular-weight materials. The base compound creates a controlled chemical environment that prevents uncontrolled acid diffusion.
3Use of energy by moving object
If inorganic resist composition is used, then sensitivity is improved, but solubility in resist solvents deteriorates and shelf stability decreases
Solution Approach 1:
The patent creates a composite molecular resist composition that combines organic low-molecular-weight materials with specific functional components (acid generators, base compounds). This composite approach integrates the high sensitivity of inorganic-like performance with the solubility and stability of organic materials, achieving a balance between sensitivity and manufacturability through synergistic component interaction.
4Measurement precision
If EUV lithography is used to form smaller patterns, then resolution is improved, but the influence of shot noise increases
Solution Approach 1:
The patent employs preliminary action by pre-optimizing the resist composition to have extremely low acid diffusion characteristics through low-molecular-weight design. This preliminary preparation of the resist system creates a buffer against shot noise effects, allowing the resist to maintain pattern fidelity even under the stochastic conditions of EUV exposure with low photon counts.
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 molecular resist composition achieves high sensitivity, improved resolution, and reduced LWR, making it suitable for precise micropatterning, while also being effective in forming small-size patterns with enhanced in-film uniformity and contrast.
Implementation Method 1
a molecular resist composition comprising an onium salt containing a cation having a cyclic ether site
Implementation Method 2
an onium salt containing a cation having a cyclic ether site
Data Source
AI summary
The negative-tone molecular resist composition comprises an onium salt containing a cation having a cyclic ether site and an organic solvent has a high sensitivity and forms a resist film with improved resolution and LWR when processed by photolithography using high-energy radiation. The molecular resist composition of the invention meets both high sensitivity and high resolution and is improved in LWR when processed by photolithography using high-energy radiation, especially EB or EUV lithography. The resist composition is quite useful for precise micropatterning.