Resist Underlayer Film Composition for Dry Etching Resistance
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Solution Overview
Problem
The challenge in semiconductor device manufacturing is to achieve better dry etching resistance and finer patterning capabilities while maintaining film thickness uniformity and preventing pattern collapse, especially as pattern sizes continue to miniaturize.
Innovation Solution
A composition for forming a resist underlayer film is developed, comprising a polymer with a specific structure represented by the general formula (1) and an organic solvent. This polymer has a molecular weight of 300 to 3,000 and lacks repeating units with hydroxy groups or heteroaromatic rings, enabling the formation of a high-carbon film with enhanced dry etching resistance through thermal decomposition and the creation of a diamond-like carbon structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the photoresist film is thinned to enable finer patterning, then the pattern resolution is improved, but the dry etching resistance is reduced
Solution Approach 1:
The invention divides the resist system into two separate layers: a photoresist film for patterning and an organic underlayer film for etching resistance. This segmentation allows each layer to be optimized independently - the photoresist film can be made thin for high resolution patterning, while the underlayer film provides the necessary dry etching resistance during substrate processing.
Solution Approach 2:
The organic underlayer film acts as an intermediary between the photoresist film and the substrate. It serves as a protective mask during dry etching, transferring the pattern from the photoresist to the substrate while protecting the substrate from direct etching damage. The underlayer film has high dry etching resistance and carbon content to withstand the etching process.
2Manufacturing precision
If a resin with low light absorption is used to improve resolution, then the pattern fidelity is improved, but the dry etching resistance is reduced
Solution Approach 1:
The invention separates the functions of light absorption and etching resistance into different materials. The photoresist film uses resins with low light absorption (such as novolak, polyhydroxystyrene, or aliphatic polycyclic resins) for high resolution patterning, while the organic underlayer film uses high carbon content materials (such as cycloolefin copolymer, cycloolefin, or carbazole derivatives) for dry etching resistance.
Solution Approach 2:
The invention creates a composite resist system combining two different polymer materials with complementary properties. The photoresist film and underlayer film are applied as separate layers, each with optimized chemical composition for its specific function, achieving both high resolution and high etching resistance that cannot be obtained with a single material.
3Length of moving object
If the photoresist film thickness is reduced for miniaturization, then the pattern size is reduced, but the aspect ratio increases causing pattern collapse
Solution Approach 1:
The invention separates the patterning function from the structural support function. The thin photoresist film (50-200 nm) provides the fine pattern definition, while the organic underlayer film (50-200 nm) provides structural stability and prevents pattern collapse during processing. The underlayer film's high carbon content and crosslinking capability enhance pattern stability.
Solution Approach 2:
The invention changes the chemical parameters of the underlayer film to optimize pattern stability. The underlayer film uses polymers with high carbon content (90-99 wt%) and specific functional groups that enable crosslinking upon heating, increasing the film's mechanical strength and stability to prevent pattern collapse during subsequent processing steps.
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 proposed composition achieves significantly improved dry etching resistance and allows for the formation of fine patterns with high precision, while maintaining film thickness uniformity and preventing pattern collapse, even on substrates with complex structures or high aspect ratios.
Implementation Method 1
enabling the formation of a high-carbon film with enhanced dry etching resistance through thermal decomposition and the creation of a diamond-like carbon structure
Data Source
AI summary
The present invention is a composition for forming a resist underlayer film, containing: (A) a polymer having a structure represented by the following general formula (1) as a repeating unit; and (B) an organic solvent, where the polymer (A) has a molecular weight of 300 to 3,000, and the polymer (A) contains neither a repeating unit containing a hydroxy group as a substituent nor a repeating unit containing a heteroaromatic ring, and where Ar represents an unsubstituted divalent aromatic group having 6 to 30 carbon atoms. This can provide a composition for forming a resist underlayer film with which it is possible to form a resist underlayer film that exhibits much better dry etching resistance than those of conventional organic underlayer film materials.Ar—CH2 (1)