Resist Underlayer Film Composition for Thin EUV Pattern Uniformity
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Solution Overview
Problem
In semiconductor lithography, particularly for EUV exposure, forming a resist underlayer film with a thickness of 32 nm or less is challenging due to substrate influences, leading to pinholes, aggregation, and defects, and requires improved adhesion, sensitivity, and reduced line width roughness for precise pattern formation.
Innovation Solution
A resist underlayer film-forming composition comprising a solvent and a reaction product of compounds with specific functional groups, including an organic group, epoxy-reactive groups, and a crosslinking agent, applied to a semiconductor substrate, followed by baking and exposure, to enhance film uniformity and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a thin resist underlayer film (32 nm or less) is formed for EUV exposure, then the line width can be reduced to achieve higher integration, but pinholes and aggregation occur due to substrate influence
Solution Approach 1:
The patent introduces a specifically designed resist underlayer film composition as an intermediary layer between the semiconductor substrate and the resist film. This underlayer film contains a polymer with epoxy groups that react with the substrate surface, creating a stable intermediate interface that prevents direct substrate influence on the thin resist film, thereby eliminating pinholes and aggregation while maintaining the required thin profile for 32 nm line width
Solution Approach 2:
The patent modifies the chemical composition parameters of the underlayer film by incorporating polymers with specific epoxy group content and molecular weight ranges. These parameter changes optimize the film's adhesion properties and uniformity, allowing the formation of defect-free thin films at 32 nm or less thickness
2Manufacturing precision
If the resist underlayer film thickness is reduced to 32 nm or less, then EUV pattern resolution is improved, but adhesion and sensitivity deteriorate
Solution Approach 1:
The underlayer film serves as a mediator that enhances the interface between substrate and resist. The epoxy-containing polymer in the underlayer forms strong chemical bonds with the substrate while providing sufficient thickness for adhesion, thereby improving both pattern resolution and adhesion/sensitivity simultaneously
Solution Approach 2:
The underlayer film is formulated as a composite material containing polymer main chains with epoxy functional groups. This composite structure combines the mechanical properties needed for adhesion with the chemical reactivity required for sensitivity, resolving the contradiction between thin film resolution and adhesion performance
3Ease of manufacture
If conventional polymers are used in the resist underlayer film, then formulation is simpler, but pinholes and aggregation occur due to substrate influence
Solution Approach 1:
The patent specifies precise parameter ranges for the polymer components, including molecular weight (10,000-1,000,000), epoxy group content (0.1-10 mmol/g), and specific structural formulas. These parameter changes create a formulation that is slightly more complex but dramatically improves film uniformity by preventing pinholes and aggregation through optimized chemical properties
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 improved adhesion and sensitivity, reducing line width roughness and enabling the formation of precise, defect-free resist patterns, especially in EUV and electron beam lithography.
Implementation Method 1
a reaction product of: Compound (A) represented by formula (1), Compound (B) having two functional groups having reactivity with an epoxy group, and Compound (C) having a functional group having reactivity with an epoxy group
Implementation Method 2
wherein the reaction product is dissolved in the solvent
Data Source
AI summary
A composition forms a resist underlayer film that enables formation of a desired resist pattern; and a method produces a resist pattern and a method produces a semiconductor device, which each use the resist underlayer film-forming composition. This resist underlayer film-forming composition contains a reaction product obtained from: a compound (A) that is dissolved in a solvent and that is represented by formula (1) (in formula (1), A represents an organic group including an aliphatic ring, an aromatic ring, or a heterocyclic ring); a compound (B) having two functional groups that are reactive with respect to an epoxy group; and a compound (C) having one functional group that is reactive with respect to an epoxy group.