Fluorinated Resist Composition for High-Resolution Lithography
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Solution Overview
Problem
Current positive resist compositions face challenges in achieving high sensitivity, resolution, and low line width roughness (LWR) while minimizing acid diffusion, which affects the formation of fine patterns in microelectronic devices, particularly at the 5-nm node and beyond.
Innovation Solution
A positive resist composition is developed using a base polymer with repeat units of an ammonium salt of specific fluorinated compounds, which controls acid diffusion by preventing agglomeration through fluorine repulsion, combined with carboxy or phenolic hydroxy groups substituted with acid labile groups to enhance dissolution contrast and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If acid diffusion is suppressed by reducing temperature and/or time of post-exposure bake, then resolution is improved, but sensitivity and contrast drastically reduce
Solution Approach 1:
The patent changes the chemical parameters of the acid generator by using fluorinated onium salts with specific molecular structures that generate bulky fluorinated acids. This chemical parameter change allows the acid to diffuse a controlled distance while maintaining high reactivity, thus achieving both high resolution and high sensitivity without compromising contrast
Solution Approach 2:
The patent employs a composite resist composition combining fluorinated onium salts as acid generators with specific base polymers and additives. This composite material system enables simultaneous optimization of acid diffusion control, sensitivity, and contrast by leveraging the synergistic effects of different components
2Manufacturing precision
If acid diffusion distance is reduced to improve resolution, then manufacturing precision is improved, but sensitivity and dissolution contrast decline
Solution Approach 1:
The patent modifies the physical-chemical parameters of the generated acid by using fluorinated onium salts that produce bulky fluorinated acids with specific diffusion characteristics. This parameter optimization enables the acid to travel just enough distance to provide adequate exposure while maintaining sharp pattern definition and high dissolution contrast
3Productivity
If conventional acid generators are used to maintain sensitivity, then productivity is improved, but acid diffusion causes image blur and resolution loss
Solution Approach 1:
The patent changes the molecular weight and steric parameters of the acid generator output by selecting fluorinated onium salts that generate bulky fluorinated acids. These acids have reduced diffusion coefficients compared to conventional acids, preventing image blur while maintaining the sensitivity needed for productive manufacturing
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 sensitivity, resolution, and reduced edge roughness, forming patterns with improved critical dimension uniformity and size variation, making it suitable for advanced microelectronic device manufacturing.
Implementation Method 1
controls acid diffusion by preventing agglomeration through fluorine repulsion
Implementation Method 2
this acid labile group is less liable to elimination reaction, the contrast enhancing effect is insufficient
Implementation Method 3
The addition of an acid generator capable of generating a bulky acid is an effective means for suppressing acid diffusion
Data Source
AI summary
A positive resist composition comprising a base polymer comprising repeat units having the structure of an ammonium salt of a fluorinated carboxylic acid, fluorinated phenol, fluorinated sulfonamide, fluorinated alcohol, fluorinated 1,3-diketone, fluorinated β-keto ester, or fluorinated imide exhibits a high sensitivity, high resolution, low edge roughness and small size variation, and forms a pattern of good profile after exposure and development.