Positive Resist Composition with Nitrogen-Containing Tertiary Ester for High Resolution
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Solution Overview
Problem
The challenge in microelectronic device manufacturing is to achieve high sensitivity and resolution while minimizing acid diffusion in resist films, which is crucial for pattern formation at the 10-nm node and beyond, as increased accelerating voltage in electron beam exposure systems reduces resist film sensitivity and leads to image blurs due to acid diffusion.
Innovation Solution
A positive resist composition is developed using a base polymer with recurring units containing a nitrogen-containing tertiary ester structure, which minimizes acid diffusion and enhances dissolution contrast, combined with carboxyl or phenolic hydroxyl groups substituted by acid labile groups, to achieve high sensitivity and resolution with improved edge roughness and size variation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the accelerating voltage of the electron beam exposure system is increased to improve resolution and reduce forward scattering, then the resolution and dimensional control are improved, but the sensitivity of the resist film decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the resist film by incorporating specific base polymers with carboxyl or phenolic hydroxyl groups substituted by acid labile groups, and adding polymeric amines with specific structures. This compositional parameter change enables the resist to achieve both high sensitivity and high resolution when exposed to high accelerating voltage electron beams, resolving the contradiction between sensitivity and resolution.
Solution Approach 2:
The patent creates a composite resist system by combining multiple components: base polymer with acid labile groups, polymeric amine with specific structural features, and acid generator. This composite material approach allows the resist to simultaneously achieve high sensitivity (through acid generation efficiency) and high resolution (through controlled acid diffusion and dissolution contrast), overcoming the limitations of single-component resists at high accelerating voltages.
2Manufacturing precision
If the acid diffusion distance is reduced to improve resolution by suppressing acid diffusion, then the resolution is improved, but the sensitivity drops due to loss of dissolution contrast
Solution Approach 1:
The patent applies local quality control by using polymeric amines with specific local structural features (aliphatic hydrocarbon groups with 3-10 carbon atoms) that create localized acid diffusion barriers. This local structural modification allows acid diffusion to be suppressed in the critical regions near the exposure site while maintaining overall sensitivity through the distributed acid generation throughout the polymer structure.
Solution Approach 2:
The patent modifies the chemical parameters of the resist system by introducing polymeric amines with specific molecular weight ranges and structural compositions. These parameter changes enable the system to achieve short acid diffusion distances for high resolution while maintaining sensitivity through optimized dissolution contrast, as the polymeric amine structure provides both acid diffusion suppression and adequate solubility differentiation between exposed and unexposed regions.
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 resist composition exhibits high sensitivity, resolution, and reduced edge roughness, forming patterns with good profiles suitable for VLSIs and photomasks, effectively addressing the limitations of existing resist materials in fine pattern formation.
Implementation Method 1
the exposure system for mask manufacturing made a transition from the laser beam exposure system to the EB exposure system
Implementation Method 2
chemically amplified resist compositions are studied
Implementation Method 3
a base polymer comprising recurring units having a carboxyl group in which the hydrogen is substituted by a nitrogen-containing tertiary hydrocarbon group
Implementation Method 4
not only an improvement in dissolution contrast is important as previously reported
Data Source
AI summary
A positive resist composition comprising a base polymer comprising recurring units having a nitrogen-containing tertiary ester structure exhibits a high sensitivity, high resolution, low edge roughness (LER, LWR) and small size variation, and forms a pattern of good profile after exposure and development.