Silicon Resist Underlayer Composition for EUV Pattern Stability
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Solution Overview
Problem
The increasing miniaturization of semiconductor devices demands a resist underlayer film that prevents resist pattern collapse and improves resolution, which existing technologies have not adequately addressed.
Innovation Solution
A silicon-containing resist underlayer film with a maximum optical absorption coefficient of 0.05 or greater in the 220 nm to 300 nm wavelength range, incorporating nitrophenyl, methoxyphenyl sulfonyl, or phenanthryl groups, and a polysiloxane-based composition for EUV lithography applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the wavelength of actinic ray is shortened to achieve higher resolution, then the resolution is improved, but the reflection from substrate increases causing pattern collapse
Solution Approach 1:
A silicon-containing resist underlayer film is introduced as an intermediary layer between the photoresist and substrate. This underlayer film absorbs secondary electrons generated during EUV lithography, preventing them from reaching the substrate and causing pattern collapse. The underlayer film thus mediates the interaction between the actinic rays and substrate, enabling high-resolution patterning while suppressing harmful reflections.
Solution Approach 2:
The patent converts the harmful effect of secondary electron generation into a beneficial outcome by using the silicon-containing underlayer film to absorb these electrons. The underlayer film transforms the potentially damaging secondary electrons into absorbed energy within the film itself, protecting the resist pattern from collapse and actually improving pattern fidelity.
2Object-affected harmful factors
If a hard mask underlayer film is used to prevent reflection, then the antireflection effect is achieved, but the composition difference between resist and hard mask causes removal difficulty
Solution Approach 1:
The patent changes the compositional parameters of the underlayer film from traditional metal-containing hard masks to a silicon-containing organic compound-based film. This compositional change allows the underlayer film to have similar chemical characteristics to the photoresist, enabling both layers to be removed together through standard wet etching processes. The silicon content provides antireflection functionality while the organic nature ensures ease of removal.
3Object-affected harmful factors
If conventional underlayer films are used, then basic antireflection is provided, but they cannot prevent collapse of fine resist patterns
Solution Approach 1:
The patent employs a composite material composition containing silicon-containing organic compounds with specific functional groups (carboxyl, hydroxyl, or amino groups). This composite structure combines the antireflection properties of silicon with the pattern stability provided by the organic compound matrix, creating a material that simultaneously addresses both reflection prevention and pattern collapse issues.
Solution Approach 2:
The underlayer film is designed with specific local chemical properties through the inclusion of silicon-containing organic compounds with functional groups that can interact with both the photoresist and substrate. This local chemical functionality provides targeted protection against pattern collapse at the critical interface region while maintaining overall film stability.
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 silicon-containing resist underlayer film effectively absorbs secondary electrons, preventing pattern collapse and enhancing resolution in EUV lithography by providing high contrast and stability.
Implementation Method 1
The silicon-containing resist underlayer film effectively absorbs secondary electrons, preventing pattern collapse and enhancing resolution in EUV lithography
Implementation Method 2
a maximum optical absorption coefficient (k value) in a wavelength range from 220 nm to 300 nm of 0.05 or greater
Data Source
AI summary
A silicon-containing resist underlayer film having a maximum optical absorption coefficient (k value) in a wavelength range from 220 nm to 300 nm of 0.05 or greater.