Resist Underlayer Composition for Fine Pattern Adhesion and Uniformity
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving fine patterning with thin resist layers that maintain adhesion to photoresist, uniform thickness, and high refractive index while ensuring resistance to etching, particularly as patterns approach several tens of nanometers in size.
Innovation Solution
A resist underlayer composition comprising a polymer with specific structural units and a solvent, which enhances sensitivity to exposure light and improves uniformity and adhesion, incorporating additives like surfactants and thermal acid generators to support pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the photoresist layer thickness is reduced for fine patterning, then the pattern size can be reduced to several tens of nanometers, but the adhesion to the substrate deteriorates and the pattern may collapse
Solution Approach 1:
A resist underlayer is introduced as an intermediary component between the photoresist layer and the substrate. This underlayer has high adhesion to both the photoresist and substrate, providing mechanical support to prevent pattern collapse while enabling the photoresist layer to be made thinner for fine patterning.
Solution Approach 2:
The resist underlayer is formed using a copolymer comprising specific structural units with high refractive index and adhesion properties. This composite material structure provides both the mechanical strength needed to support thin photoresist patterns and the optical properties required for lithographic processing.
2Length of moving object
If the resist underlayer thickness is reduced to enable fine patterning, then the pattern resolution improves, but the uniformity of the underlayer becomes more difficult to maintain
Solution Approach 1:
The viscosity of the resist underlayer composition is precisely controlled within the range of 50 to 500 cP at 25°C, and the polymer concentration is optimized to 1-20 wt%. These parameter changes ensure uniform film formation even at reduced thicknesses, maintaining manufacturing precision while enabling fine patterning.
3Length of moving object
If the photoresist layer is made thin for fine patterning, then the resolution increases, but the sensitivity to exposure light decreases
Solution Approach 1:
The resist underlayer acts as an optical intermediary that enhances the effective sensitivity of the thin photoresist layer. By optimizing the underlayer's refractive index and thickness, light transmission is improved, compensating for the reduced photoresist thickness and maintaining exposure sensitivity for fine patterning.
4Manufacturing precision
If the resist underlayer has high refractive index for improved lithographic performance, then the patterning quality improves, but the material selection and formulation become more complex
Solution Approach 1:
A copolymer is used that inherently combines high refractive index properties with good adhesion and film-forming characteristics. This composite material approach achieves superior patterning quality while simplifying the overall formulation compared to using multiple separate materials or complex additive systems.
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 improves patterning performance and energy efficiency by enhancing sensitivity and uniformity, ensuring the resist underlayer supports fine patterning without collapsing the photoresist pattern.
Implementation Method 1
improving sensitivity to an exposure light source
Data Source
AI summary
Disclosed are a resist underlayer composition, and a method of forming a photoresist pattern using the resist underlayer composition. The resist underlayer composition includes a polymer including a structural unit represented by Chemical Formula 1, and a solvent. The definition of Chemical Formula 1 is as described in the specification.