Resist Underlayer Film Composition for Stepped Substrate Flatness
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Solution Overview
Problem
Existing resist underlayer films struggle to form flat films with small thickness differences on stepped substrates, exhibiting insufficient coating and high step differences, which complicates semiconductor processing.
Innovation Solution
A composition containing a compound with aromatic hydrocarbon groups at the terminal of a polymer skeleton, combined with a solvent having a boiling point of 160° C or higher, is used to form a resist underlayer film that provides a favorable dry etching rate ratio and optical constants, enabling flat film formation on stepped substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional resist underlayer film composition is used, then the etching resistance is sufficient, but the coating on stepped substrate is insufficient and the film thickness difference is large
Solution Approach 1:
The patent modifies the chemical composition parameters of the resist underlayer film by incorporating specific compounds with aromatic hydrocarbon groups (Formula 1) and selecting solvents with boiling points of 160°C or higher. These parameter changes enable the composition to achieve both sufficient etching resistance and improved coating uniformity on stepped substrates, reducing film thickness differences.
Solution Approach 2:
The patent creates a composite material system by combining the compound of Formula (1) containing aromatic hydrocarbon groups with specifically selected high-boiling-point solvents. This composite composition achieves synergistic effects where the aromatic hydrocarbon groups provide etching resistance while the high-boiling-point solvent ensures uniform coating and flat film formation on stepped substrates.
2Reliability
If the composition is applied on stepped substrate, then the etching resistance is maintained, but the coating step difference is large and flatness is poor
Solution Approach 1:
The patent changes the physical parameters of the composition by selecting solvents with boiling points of 160°C or higher. This parameter change improves the coating behavior on stepped substrates, reducing the coating step difference and enhancing film flatness while preserving the etching resistance provided by the aromatic hydrocarbon groups.
Solution Approach 2:
The high-boiling-point solvent acts as an intermediary that mediates between the compound of Formula (1) and the stepped substrate. It provides sufficient processing time and controlled evaporation characteristics to ensure uniform coating across height variations, resulting in reduced step differences and improved flatness while maintaining the etching resistance of the aromatic hydrocarbon groups.
3Illumination intensity
If a polymer with benzene ring is used, then the optical constant is improved, but the coating on stepped substrate remains insufficient
Solution Approach 1:
The patent combines the optical properties of aromatic hydrocarbon groups (benzene rings) with the coating performance of high-boiling-point solvents in a composite material system. The aromatic groups provide the necessary optical constant for anti-reflective coating, while the high-boiling-point solvent ensures uniform coating distribution on stepped substrates, resolving the contradiction between optical performance and coating quality.
Data Source
AI summary
A composition for forming a resist underlayer film which enables to form a flat film with a favorable coating even on a so-called stepped substrate and a small film thickness difference after embedding, and also a polymer as an important component of the composition for forming a resist underlayer film, a resist underlayer film formed using the composition for forming a resist underlayer film, and a method of producing a semiconductor device. The composition for forming a resist underlayer film, includes a compound of the following Formula (1) and a solvent:(wherein, Ar1, Ar2, Ar3 and Ar4 are each independently a substitutable monovalent aromatic hydrocarbon group, a, b, c, and d are each 0 or 1, and a+b+c+d=1).