Organic Hard Mask Composition for Lithography Etching
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Solution Overview
Problem
In semiconductor manufacturing, the integration of shorter wavelengths in lithography processes leads to issues with diffuse reflection and standing waves, requiring an anti-reflective coating that also functions as an organic hard mask layer without intermixing with inorganic layers, while maintaining selectivity ratios similar to or less than those of the resist or semiconductor substrate, and allowing for effective light absorption and dry etching.
Innovation Solution
A composition comprising a polymer with specific structural units, a crosslinkable compound with blocked isocyanate groups, and a solvent, forming an organic hard mask layer that can be used at the lowest layer in lithography, providing excellent pattern formation, anti-reflective properties, and selective dry etching capabilities without intermixing with inorganic layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional resist underlayer film with high etching rate is used, then substrate processing can be performed, but the selectivity ratio of dry etching rate becomes too high causing intermixing with inorganic hard mask layers
Solution Approach 1:
The patent changes the chemical composition parameters of the resist underlayer film by incorporating specific polymers (polymer A with carboxyl or hydroxyl groups, polymer B with carboxyl groups) and crosslinkable compounds to achieve a selectivity ratio of dry etching rate between 0.1-10, preventing intermixing while maintaining etching capability
Solution Approach 2:
The patent uses a composite material system consisting of multiple polymer components (polymer A and polymer B) combined with crosslinkable compounds to create a resist underlayer film with controlled etching properties that maintains appropriate selectivity ratio
2Manufacturing precision
If the resist film thickness is reduced to prevent pattern collapse, then resolution is improved, but sufficient mask function for substrate processing cannot be secured
Solution Approach 1:
The patent divides the protective function into two separate layers: a thin resist film for pattern definition and a resist underlayer film for mask function during substrate processing, allowing each layer to be optimized independently
Solution Approach 2:
The resist underlayer film acts as an intermediary between the thin resist pattern and the substrate, providing the necessary mask function for etching while the thin resist maintains high resolution
3Device complexity
If no anti-reflective coating is used, then the process is simpler, but diffuse reflection and standing waves occur at shorter wavelengths
Solution Approach 1:
The patent combines the anti-reflective coating function and the resist underlayer/mask function into a single integrated layer, eliminating the need for a separate anti-reflective coating while maintaining both functions
Solution Approach 2:
The resist underlayer film is designed to perform multiple functions simultaneously: providing anti-reflective properties to prevent diffuse reflection and standing waves, maintaining appropriate etching selectivity, and serving as a mask during substrate processing
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 organic hard mask layer effectively absorbs reflected light, maintains desired selectivity ratios, and enables precise pattern transfer and etching, preventing pattern collapse and ensuring high accuracy in semiconductor manufacturing.
Implementation Method 1
a composition for forming an organic hard mask layer... having a function to effectively absorb reflected light from the substrate when radiation light having a wavelength of 248 nm, 193 nm, 157 nm or the like is used
Implementation Method 2
a crosslinkable compound (B) including at least two of blocked isocyanate groups, methylol groups, or C1-5 alkoxymethyl groups
Data Source
AI summary
Whereas, conventionally, ashing had been used at the time of removal, the present invention provides a material for forming an organic hard mask that can be removed by an alkaline aqueous solution, and thus can be expected to reduce damage to the substrate at the time of the removal. A composition for forming an organic hard mask layer comprising: a polymer (A) including a structural unit of Formula (1) and a structural unit of Formula (2); a crosslinkable compound (B) including at least two of blocked isocyanate groups, methylol groups, or C1-5 alkoxymethyl groups; and a solvent (C), wherein an organic hard mask layer obtained from the composition for forming an organic hard mask layer is used at the lowest layer in a lithography process using a multi-layer film,wherein R1 to R4 have the same definition as ones in the specification.