Organic Underlayer Film for Semiconductor Etching Resistance
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Solution Overview
Problem
In semiconductor manufacturing, the use of organic underlayer films in multilayer resist methods faces challenges such as pattern twisting and curvature due to the properties of amorphous carbon films, and conventional resins with high carbon content suffer from etching resistance degradation due to incorporated oxygen atoms.
Innovation Solution
A composition comprising a polymer with a partial structure of condensed aromatic rings, such as fluorene, which forms a heat-curable film without crosslinking agents, providing high etching and twisting resistance while maintaining high carbon content, along with a suitable patterning process using this polymer for precise pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If amorphous carbon film is used as underlayer, then etching resistance is improved, but pattern twisting and curvature occur
Solution Approach 1:
The patent changes the chemical composition parameters of the underlayer material from conventional amorphous carbon to a specific polymer composition containing fluorinated groups and aromatic rings. This parameter change maintains high etching resistance while eliminating the pattern twisting and curvature issues associated with amorphous carbon films.
Solution Approach 2:
The patent employs a composite polymer material combining fluorinated groups (for etching resistance) with aromatic ring structures (for dimensional stability). This composite approach achieves both high etching resistance and pattern formation accuracy, resolving the contradiction between these two properties.
2Quantity of substance
If conventional high carbon content resin is used, then carbon content is improved, but etching resistance degrades due to oxygen atoms
Solution Approach 1:
The patent extracts and eliminates oxygen atoms from the polymer structure by using fluorinated groups instead of conventional oxygen-containing functional groups. This extraction of harmful oxygen elements allows the resin to maintain high carbon content while preserving etching resistance.
Solution Approach 2:
The patent changes the chemical composition by replacing oxygen-containing groups with fluorinated groups, thereby maintaining high carbon content (above 80% by weight) while preventing etching resistance degradation that occurs with conventional high-carbon resins containing oxygen.
3Strength
If CVD process is used for carbon hard mask, then etching resistance is improved, but step coverage and flatness are worsened
Solution Approach 1:
The patent replaces the CVD deposition process with a spin-coating process that applies the polymer-based underlayer. This substitution enables conformal coating over steps and trenches, achieving excellent step coverage and surface flatness while maintaining high etching resistance through the polymer's chemical composition.
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 solution enables the formation of organic films with excellent etching resistance and twisting resistance, suitable for high-aspect-ratio patterns and precise pattern formation in semiconductor devices, while maintaining high carbon content and avoiding etching resistance degradation.
Implementation Method 1
When an organic film formed from this organic film composition containing the polymer having a partial structure shown by the general formula (1A) is heated, a cured film is formed by thermal polymerization through the action of the substituent having an unsaturated bond on the fluorene ring
Data Source
AI summary
A composition for forming an organic film contains a polymer having a partial structure shown by the following general formula (1A) or (1B), and an organic solvent, where Ar1 and Ar2 represent a benzene ring or naphthalene ring which optionally have a substituent; X represents a single bond or methylene group; a broken line represents a bonding arm; R represents a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms; and W1 represents a hydroxyl group, an alkyloxy group having 1 to 10 carbon atoms, or an organic group having at least one aromatic ring optionally having a substituent. A composition for forming an organic film, the composition containing a polymer with high carbon content and thermosetting property as to enable high etching resistance and excellent twisting resistance; a patterning process using the composition; and a polymer suitable for the composition for forming an organic film.