Fullerene Derivative Resist Underlayer Film for Lithography
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Solution Overview
Problem
In microfabrication for semiconductor devices, finer patterns lead to deteriorated photoresist film resolution and pattern collapse due to high aspect ratios, and existing resist compositions lack sufficient dry etching resistance and selectivity, causing issues like wiggling and pattern transfer defects.
Innovation Solution
A resist underlayer film composition incorporating a fullerene derivative reaction product with a 1,3-diene compound derivative having an electron-withdrawing group, combined with an organic solvent, to enhance dry etching resistance and prevent wiggling, while maintaining solubility and avoiding pattern poisoning during chemical amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the thickness of photoresist film is increased to improve pattern resolution, then resolution performance is improved, but aspect ratio increases causing pattern collapse during development
Solution Approach 1:
The patent divides the single photoresist film into two separate layers: an underlayer film (10 nm-50 nm thick) providing etching resistance and an upperlayer film (50 nm-200 nm thick) providing pattern definition. This segmentation allows each layer to be optimized independently, resolving the contradiction between thickness for resolution and aspect ratio for collapse prevention.
2Shape
If photoresist film thickness is reduced to prevent pattern collapse, then pattern stability is improved, but resolution performance deteriorates
Solution Approach 1:
By segmenting the resist system into underlayer and upperlayer films, the patent enables the upperlayer to be thin for stability while the underlayer provides the necessary etching resistance, thus maintaining both pattern stability and resolution performance.
Solution Approach 2:
The underlayer film serves multiple functions: it provides etching resistance during substrate processing, supports the upperlayer film structure, and enables the use of thinner upperlayer films for better resolution. This multi-functionality resolves the contradiction between thickness reduction for stability and resolution maintenance.
3Use of energy by moving object
If photoresist composition uses resins with low light-absorbance for shorter wavelength exposure, then exposure sensitivity is improved, but dry etching resistance decreases
Solution Approach 1:
The patent assigns different functional requirements to separate layers: the underlayer film uses resins optimized for dry etching resistance (even if they have higher light absorbance), while the upperlayer film uses resins optimized for exposure sensitivity. This segmentation resolves the contradiction between exposure sensitivity and etching resistance.
Solution Approach 2:
Different resin compositions are used in different locations (layers) of the resist system. The underlayer uses high etching resistance resins where etching protection is needed, while the upperlayer uses high sensitivity resins where exposure response is critical, thus resolving the local contradiction in material properties.
4Strength
If conventional organic resins are used for underlayer film to provide etching resistance, then dry etching resistance is improved, but wiggling occurs during substrate etching
Solution Approach 1:
The patent uses a composite material system where fullerene derivatives (carbon-based molecules with high etching resistance) are incorporated into the underlayer film composition. This composite approach provides superior etching resistance while maintaining compositional stability and preventing wiggling, overcoming the limitations of conventional organic resins.
Solution Approach 2:
The patent changes the chemical composition parameters of the underlayer film by incorporating fullerene derivatives, which have unique properties (high carbon content, spherical structure) that provide both etching resistance and compositional stability, thus preventing wiggling while maintaining etching protection.
5Manufacturing precision
If multilayer resist process is implemented to improve pattern transfer accuracy, then pattern transfer fidelity is improved, but process complexity increases
Solution Approach 1:
The patent segments the resist system into two functional layers with distinct roles, enabling precise pattern transfer through the segmentation of functions. While this increases structural complexity, it simplifies the overall process by providing clear separation of concerns: underlayer for etching resistance and upperlayer for pattern definition.
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 achieves high dry etching resistance, suppresses wiggling, and prevents pattern defects, enabling precise pattern transfer to substrates with improved etching selectivity and stability.
Implementation Method 1
a first organic compound which is a reaction product of a substance having a fullerene skeleton with a 1,3-diene compound derivative having an electron-withdrawing group
Implementation Method 2
together with a solvent
Data Source
AI summary
The invention provides a composition for a resist underlayer film, the composition for a resist underlayer film to form a resist underlayer film of a multilayer resist film used in lithography, wherein the composition comprises at least (A) a fullerene derivative that is a reaction product of a substance having a fullerene skeleton with a 1,3-diene compound derivative having an electron-withdrawing group and (B) an organic solvent. There can be a composition for a resist underlayer film for a multilayer resist film used in lithography, the composition giving a resist underlayer film having excellent high dry etching resistance, capable of suppressing wiggling during substrate etching with high effectiveness, and capable of avoiding a poisoning problem in upperlayer patterning that uses a chemical amplification resist; a process for forming a resist underlayer film; a patterning process; and a fullerene derivative.