Novolac Resist Underlayer for Lithography Reflection Control
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Solution Overview
Problem
In semiconductor device production, the miniaturization of resist patterns leads to issues with resolution and collapse due to diffuse reflection and standing waves, especially with shorter wavelength light sources, requiring a resist underlayer film that prevents intermixing and provides effective anti-reflective properties while maintaining a suitable dry etching selection ratio.
Innovation Solution
A resist underlayer film-forming composition comprising a polymer with specific unit structures, including hydroxy group-substituted arylene groups and heterocyclic groups, which absorbs reflected light and offers heat resistance, allowing for precise pattern formation and etching without intermixing with the resist layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional resist underlayer film with high etching rate is used, then substrate processing efficiency is improved, but the selection ratio of dry etching rate becomes too high causing pattern distortion
Solution Approach 1:
The patent modifies the chemical composition parameters of the resist underlayer film by incorporating specific polymers (polyhydroxy aromatic ring novolac resin with carbonyl groups, polyhydrazine compounds) to adjust the dry etching rate. This changes the etching selectivity parameter to match the resist layer, preventing pattern distortion while maintaining processing efficiency.
Solution Approach 2:
The patent creates a composite resist underlayer film by combining multiple components: polyhydroxy aromatic ring novolac resin, polyhydrazine compounds, and crosslinking agents. This composite structure achieves balanced etching properties that match the resist layer, resolving the contradiction between processing efficiency and pattern fidelity.
2Manufacturing precision
If the resist film thickness is decreased to prevent pattern collapse, then resolution is improved, but sufficient film thickness for substrate processing cannot be obtained
Solution Approach 1:
The patent introduces a resist underlayer film as an intermediary between the thin resist layer and the substrate. This intermediary layer provides the necessary mechanical support and etching resistance, enabling the use of thinner resist films for improved resolution while maintaining sufficient overall film thickness for substrate processing.
Solution Approach 2:
The patent divides the protective function into two separate layers: a thin resist layer for pattern definition and a thicker resist underlayer film for mechanical support and etching resistance. This segmentation allows each layer to optimize its thickness for its specific function, resolving the contradiction between resolution and film thickness sufficiency.
3Manufacturing precision
If a resist underlayer film with different etching rate is used, then etching selectivity is improved, but intermixing with resist layer occurs causing pattern degradation
Solution Approach 1:
The patent adjusts the chemical composition parameters of the resist underlayer film to match the etching rate with the resist layer by incorporating polyhydrazine compounds and crosslinking agents. This parameter matching prevents intermixing during etching while maintaining appropriate etching selectivity for 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 composition effectively suppresses reflection, maintains a suitable dry etching selection ratio, and prevents pattern collapse, enabling high-precision lithography and efficient semiconductor device production with improved thermal stability and reduced substrate damage.
Implementation Method 1
The present invention can impart a performance that effectively absorbs reflected light from a substrate when irradiated light having a wavelength of 248 mu, 193 nm, 157 nm, or the like is used for microprocessing
Implementation Method 2
The present invention provides a resist underlayer film-forming composition for forming a resist underlayer film having heat resistance
Data Source
AI summary
There is provided resist underlayer film for lithography process with high dry etching resistance, wiggling resistance, and heat resistance. Resist underlayer film-forming composition for lithography including polymer having unit structure of Formula (1): wherein A is hydroxy group-substituted C6-40 arylene group derived from polyhydroxy aromatic compound; B is C6-40 arylene group or C4-30 heterocyclic group containing nitrogen atom, oxygen atom, sulfur atom, or combination thereof; X+ is H+, NH4+, primary ammonium ion, secondary ammonium ion, tertiary ammonium ion, or quaternary ammonium ion, T is hydrogen atom, C1-10 alkyl group or C6-40 aryl group that may be substituted with halogen group, hydroxy group, nitro group, amino group, carboxylate ester group, nitrile group, or combination thereof as substituent, or C4-30 heterocyclic group containing nitrogen atom, oxygen atom, sulfur atom, or combination thereof, B and T may form C4-40 ring together with carbon atom to which they are bonded.