Fullerene Hard-Mask Composition for Semiconductor Etching
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Solution Overview
Problem
Current hard-mask materials for semiconductor manufacturing face challenges such as swelling and comingling with resist solvents, limited carbon content, lower etching resistance, and lower thermal stability, which restrict the aspect ratio and etch depth in semiconductor devices.
Innovation Solution
A hard-mask composition comprising fullerene derivatives with exohedral rings and a crosslinking agent, formed through cycloaddition reactions, is developed to enhance film thickness retention, etching resistance, and thermal stability, using a blend of fullerenes like C60, C70, and C76, with a crosslinker like poly[(o-cresyl glycidyl ether)-co-formaldehyde], to create a robust and insoluble film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional hard-mask materials are used, then the manufacturing process is simple, but the film exhibits swelling and comingling with resist solvents, leading to poor film thickness retention
Solution Approach 1:
The patent employs a composite material system consisting of methanofullerene core structure combined with exohedral ring substituents and crosslinking agents. This composite approach creates a multi-component hard-mask material that resists swelling and comingling with resist solvents, thereby improving film thickness retention while maintaining manufacturing feasibility through spin-coating processes.
Solution Approach 2:
The patent modifies the chemical parameters of hard-mask materials by introducing exohedral rings with specific functional groups and utilizing crosslinking chemistry. These parameter changes in molecular structure and intermolecular bonding enhance the material's resistance to solvent interaction, directly improving film thickness retention without significantly complicating the manufacturing process.
2Reliability
If carbon content is increased to improve etching resistance, then etching performance improves, but thermal stability decreases
Solution Approach 1:
The patent applies local quality by differentiating functional regions within the hard-mask material structure. The methanofullerene core provides high carbon content and etching resistance, while the exohedral ring substituents and crosslinking network provide thermal stability. This spatial and functional differentiation allows the material to simultaneously achieve high etching resistance and thermal stability.
Solution Approach 2:
The patent creates a composite material where the methanofullerene core (high carbon content) is combined with exohedral ring structures and crosslinking agents (thermal stability). This composite structure resolves the contradiction by allowing each component to contribute its advantageous property: the core provides etching resistance while the peripheral structures and crosslinks provide thermal stability.
3Length of moving object
If photoresist film thickness is increased to achieve deeper etches, then etch depth increases, but pattern collapse occurs due to high aspect ratio
Solution Approach 1:
The patent introduces a multilayer hard-mask stack as an intermediary system between the thin photoresist and the substrate to be etched. This intermediate carbon-rich hard-mask layer (deposited by CVD) serves as a structural support that enables the use of thin photoresist films while achieving deep etches. The hard-mask layer compensates for the limited thickness of the photoresist, allowing high aspect ratio patterning without pattern collapse.
Solution Approach 2:
The patent transitions from a single-layer approach to a multilayer vertical stack (photoresist/silicon-rich layer/carbon layer). This dimensional organization in the vertical direction allows each layer to perform its specific function: the photoresist provides patterning, the silicon-rich layer provides etch selectivity, and the carbon layer provides structural support for high aspect ratios, thereby enabling deep etches without pattern collapse.
4Reliability
If crosslinking density is increased to improve insolubility in resist solvents, then film stability improves, but manufacturing complexity increases
Solution Approach 1:
The patent modifies the chemical parameters of the hard-mask material by incorporating crosslinking functionality into the methanofullerene structure and utilizing crosslinking agents. These parameter changes in molecular architecture create insolubility in resist solvents while maintaining compatibility with standard spin-coating and baking processes, thus improving reliability without significantly increasing manufacturing 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 exhibits improved film thickness retention, increased etching resistance, and enhanced thermal stability, allowing for higher aspect ratios and deeper etches, while maintaining insolubility in photoresist solvents, thus addressing the limitations of previous formulations.
Implementation Method 1
A hard-mask composition comprising fullerene derivatives with exohedral rings and a crosslinking agent, formed through cycloaddition reactions
Implementation Method 2
a crosslinking agent comprising two or more thermally or catalytically reactive groups
Data Source
AI summary
Disclosed and claimed herein is a composition for forming a spin-on hard-mask, having a fullerene derivative and a crosslinking agent. Further disclosed is a process for forming a hard-mask.