Anti-Reflective Coating Composition for Negative Tone Development
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Solution Overview
Problem
Conventional organic anti-reflective coating layers used in negative tone development suffer from poor adhesion to photoresist, undercut issues, and inadequate pattern profile control, especially at short wavelengths, limiting their effectiveness in photolithography processes.
Innovation Solution
A composition comprising an isocyanurate compound with specific moieties, a polymer, and an organic solvent, which forms a high refractive index coating layer with enhanced etch rate and adhesion, incorporating nitrogen, sulfur, and oxygen atoms, and a deprotecting group to improve hydrophilicity and pattern profile, along with a photoacid generator to control acid supply for vertical pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional organic anti-reflective coating layer is used in negative tone development, then the coating can be formed with simple equipment and high light absorptivity, but the adhesion to photoresist is poor and undercut occurs at the photoresist bottom
Solution Approach 1:
The patent uses a composite material consisting of an isocyanurate compound combined with a polymer containing carboxylic acid groups. This composite structure provides both the high refractive index and etch rate of isocyanurate compounds and the enhanced adhesion to photoresist provided by the carboxylic acid-containing polymer, resolving the contradiction between ease of manufacture and adhesion reliability.
Solution Approach 2:
The patent modifies the chemical composition parameters of the anti-reflective coating by incorporating specific functional groups (carboxylic acid groups) and controlling the molecular weight and structure of the polymer components. This parameter optimization enables improved adhesion to photoresist while maintaining the high refractive index and etch rate properties.
2Manufacturing precision
If the wavelength of exposure light is shortened to improve photoresist pattern resolution, then the marginal resolution improves, but optical interference effect from reflected light increases causing undercutting and notching
Solution Approach 1:
The patent converts the harmful reflected light into a beneficial effect by designing an anti-reflective coating with high light absorptivity. The coating absorbs the reflected exposure light rather than allowing it to interfere with the photoresist pattern, thereby eliminating undercutting and notching while maintaining the high resolution benefits of short wavelength exposure.
Solution Approach 2:
The anti-reflective coating acts as an intermediary layer between the photoresist and the substrate. It mediates the optical interaction by absorbing reflected light and preventing it from causing interference effects, thereby protecting the photoresist pattern from undercutting and notching while allowing short wavelength exposure for high resolution.
3Manufacturing precision
If an isocyanurate compound is used to achieve high refractive index and etch rate, then the reflectivity is controlled and pattern profile is corrected, but undercut occurs at photoresist bottom and adhesion to photoresist is poor
Solution Approach 1:
The patent creates a composite system where isocyanurate compounds provide high refractive index and etch rate for good pattern profile control, while the added polymer containing carboxylic acid groups provides strong adhesion to photoresist. The synergistic combination resolves the contradiction between pattern profile control and adhesion reliability.
Solution Approach 2:
The patent applies different functional properties to different components of the coating system: the isocyanurate compound provides optical and etching properties in the bulk coating, while the carboxylic acid-containing polymer provides adhesion properties at the photoresist interface. This local quality differentiation resolves the contradiction between pattern profile control and adhesion.
Data Source
AI summary
Provided is a composition for forming an organic anti-reflective coating layer used in a negative tone development, which not only enhance an adhesion to a photoresist while having a high refractive index and a high etch rate but also improve a pattern profile of undercut etc. The composition an isocyanurate compound containing at least one moiety which is represented by Formula 2; a polymer represented by Formula 3 and an organic solvent for dissolving the above-mentioned components.