Lithography Underlayer Film Composition for Finer Patterns
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Solution Overview
Problem
Current materials for resist underlayer films in lithography lack simultaneous high solvent solubility for wet processes, heat resistance, and etching resistance, making it difficult to achieve finer patterns without pattern collapse and sufficient substrate processing.
Innovation Solution
A composition comprising 20-99% solvent and 27-100% of a specific compound with a cyanate group, which acts as a crosslinking agent, enhancing heat resistance and etching resistance while allowing high solubility in organic solvents for wet processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional resist underlayer film material is used, then the film can be formed, but it lacks simultaneous high solvent solubility for wet processes, heat resistance, and etching resistance
Solution Approach 1:
The patent uses a composite material system consisting of a cyanate group-containing polymer as the base resin and a crosslinking agent. The polymer provides solvent solubility and film formation, while the crosslinking agent forms a crosslinked network structure that provides heat resistance and etching resistance. This composite approach allows simultaneous achievement of multiple properties that cannot be obtained with a single material.
Solution Approach 2:
The patent changes the chemical structure parameters of the polymer by incorporating cyanate groups, which enable crosslinking reactions. This structural modification allows the material to transform from a simple linear polymer to a crosslinked network, fundamentally changing its thermal and chemical resistance properties while maintaining solvent solubility through controlled crosslinking density.
2Manufacturing precision
If the resist film is made thinner to achieve finer patterns, then the resolution improves, but it becomes difficult to achieve sufficient film thickness for substrate processing
Solution Approach 1:
The patent introduces a new functional dimension by adding an underlayer film between the substrate and the resist film. This underlayer film provides mechanical support and etching resistance, enabling the resist film to be made thinner for finer patterns while still maintaining sufficient overall film thickness for proper substrate processing and pattern support.
3Reliability
If an amorphous carbon underlayer film is used for high etching resistance, then etching resistance improves, but the material cannot be dissolved in solvent for wet processes
Solution Approach 1:
The patent changes the chemical composition parameters by using a cyanate group-containing polymer instead of amorphous carbon. This polymer can be dissolved in organic solvents for wet process application. After deposition, crosslinking creates a dense network structure that provides etching resistance comparable to or exceeding amorphous carbon, while maintaining solvent processability during the deposition stage.
4Temperature
If a crosslinking agent is added to enhance heat resistance, then heat resistance improves, but the composition complexity increases
Solution Approach 1:
The crosslinking agent serves multiple functions: it provides heat resistance through crosslinked network formation, enhances etching resistance by creating a denser structure, and improves mechanical strength. By using a single additive that performs multiple functions, the patent avoids the need for multiple separate components, thereby limiting the increase in composition complexity.
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 enables the formation of an underlayer film that is resistant to high-temperature baking and oxygen plasma etching, maintaining adhesiveness with resist layers and intermediate films, thus preventing pattern collapse and allowing for finer pattern formation.
Implementation Method 1
a compound having a cyanate group represented by formula (2)... acts as a crosslinking agent, enhancing heat resistance and etching resistance
Implementation Method 2
the component (A) other than the solvent component (S) comprises 27 to 100% by mass of the compound represented by formula (2) and further comprises an acid generating agent
Data Source
AI summary
The composition for forming an underlayer film for lithography according to the present invention contains a compound represented by a specific formula (1) and 20 to 99% by mass of a solvent component (S), in which 27 to 100% by mass of the compound represented by the formula (1) is included in a component (A) other than the solvent component (S).