Polysiloxane Gap-Fill Coating for Pattern Inversion Lithography
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Solution Overview
Problem
The challenge in semiconductor device production is the difficulty in achieving finer patterns due to issues with resolution and pattern collapse, as well as the need for a resist underlayer film with a specific etching ratio and adhesion properties, which existing anti-reflective coatings and photoresist compositions fail to address effectively.
Innovation Solution
A polysiloxane-based coating composition is developed, comprising a hydrolysis-condensate of hydrolysable silane with specific molecular ratios and structures, which forms a polysiloxane film that fills gaps in the organic underlayer film pattern and provides enhanced adhesion and etch-back capabilities for pattern inversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the film thickness of resist is decreased to achieve finer patterns, then resolution is improved, but the film thickness becomes insufficient for substrate processing
Solution Approach 1:
The patent divides the single resist film into multiple functional layers: a thin resist film (50-200 nm) for high-resolution patterning and a separate underlayer film (10-100 nm) for substrate processing. This segmentation allows each layer to optimize its thickness for its specific function, resolving the contradiction between thin film requirements for resolution and sufficient thickness for processing.
Solution Approach 2:
The patent introduces a vertical dimensional structure with multiple layers instead of relying on a single thick resist film. By stacking the resist film over the underlayer film, the system achieves both thin film characteristics at the resist level (for resolution) and sufficient total thickness at the underlayer level (for processing), effectively solving the thickness contradiction through dimensional organization.
2Productivity
If a conventional resist underlayer film with high etching rate is used, then substrate processing is facilitated, but the selection ratio of dry etching rate becomes unbalanced
Solution Approach 1:
The patent applies local quality by designing the underlayer film with specific chemical composition (silane-modified polymer) that provides locally optimized etching characteristics. The underlayer film has moderate etching rate with balanced selection ratios against both the resist film and semiconductor substrate, creating locally appropriate etching properties rather than uniformly high etching rate throughout the structure.
Solution Approach 2:
The underlayer film is formulated as a composite material containing silane-modified polymer with specific functional groups that provide controlled etching behavior. This composite structure enables the film to exhibit balanced etching selectivity, facilitating substrate processing while maintaining precise etching ratios relative to adjacent layers.
3Manufacturing precision
If pattern inversion is implemented to achieve finer patterns, then resolution is improved, but the process complexity increases due to additional steps
Solution Approach 1:
The patent implements preliminary action by pre-forming the underlayer film with appropriate etching characteristics before resist patterning. This underlayer film is prepared in advance to provide the necessary structural support and etching selectivity, enabling subsequent pattern inversion processes to proceed more smoothly with reduced complexity.
Solution Approach 2:
The underlayer film serves as an intermediary layer between the resist film and semiconductor substrate, mediating the pattern inversion process. This intermediate structure facilitates controlled etching and pattern transfer, reducing the complexity of direct pattern inversion on the substrate by providing a buffer layer with optimized properties.
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 polysiloxane coating composition effectively fills gaps in the organic underlayer film pattern, enabling high-aspect-ratio pattern inversion and improved substrate processing by providing higher adhesion and allowing for gas etching and ashing treatments, thus overcoming the limitations of conventional techniques.
Implementation Method 1
a coating composition for pattern inversion that fills a gap in an organic underlayer film pattern
Implementation Method 2
a polysiloxane obtained by a reaction of an alcohol with a silanol group in a hydrolysis-condensate of a hydrolysable silane
Implementation Method 3
a polysiloxane obtained by a reaction of an alcohol with a silanol group in a hydrolysis-condensate of a hydrolysable silane
Data Source
AI summary
A coating composition for pattern inversion that fills a gap in an organic underlayer film pattern formed on a substrate to be processed by transferring a resist pattern to an underlayer and forms a flat polysiloxane film, the coating composition including a polysiloxane obtained by a reaction of an alcohol with a silanol group in a hydrolysis-condensate of a hydrolysable silane having a hydrolysable silane containing in the molecule four hydrolysable groups, in a ratio of 50% by mole to 100% by mole relative to the total amount of silanes. The hydrolysable silane is represented by Formula (1):R1aSi(R2)4-a Formula (1)and contains 50% by mole to 100% by mole of a hydrolysable silane in which a is 0 and 0% by mole to 50% by mole of a hydrolysable silane in which a is 1 or 2. The alcohol is propylene glycol monomethyl ether, propylene glycol monoethyl ether, or 3-methoxybutanol.