Photoacid Generator Polymer for Microlithography Resolution
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Solution Overview
Problem
Advanced microlithography technologies face challenges with line width roughness (LWR) and line edge roughness (LER) due to uneven distribution of photoacid generators (PAGs) in photoresist films, leading to poor resolution and etch control, especially in transistor and gate architectures.
Innovation Solution
Development of novel chain transfer agents for reversible addition-fragmentation transfer (RAFT) controlled polymerization reactions, which produce polymers with narrow polydispersity and well-dispersed photoacid generator moieties, improving PAG dispersion and molecular weight control in photoresist matrices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If photoacid generators are incorporated into photoresist formulations by preparing a physical blend, then the PAG can be added to the formulation, but an inhomogeneous distribution of PAG occurs in the photoresist film leading to uneven acid generation and greater line edge roughness
Solution Approach 1:
The patent merges the PAG function with the polymer backbone by covalently attaching PAG-containing monomers during polymerization. This integration ensures uniform distribution of PAG throughout the polymer matrix, eliminating the inhomogeneity problem associated with physical blends while maintaining ease of formulation incorporation.
Solution Approach 2:
The patent changes the chemical state of PAG from separate molecular entities (physical blend) to covalently bonded units within polymer chains. This parameter change from physical mixing to chemical integration fundamentally improves distribution uniformity while maintaining manufacturing feasibility through controlled polymerization processes.
2Manufacturing precision
If the PAG is attached to the polymer backbone, then PAG dispersion in the photoresist film is improved, but the PAGs are doubly distributed between both polymer chains and within polymer chains depending on reactivity ratio
Solution Approach 1:
The patent applies local quality by using specific monomers with controlled reactivity ratios that preferentially incorporate PAG-containing units at desired positions along polymer chains. This localized control of monomer incorporation ensures uniform PAG distribution both between chains and within chains, overcoming the random distribution problem.
Solution Approach 2:
The patent employs feedback mechanisms through controlled polymerization conditions and monomer feed rates to regulate PAG distribution. By monitoring and adjusting polymerization parameters, the process ensures uniform PAG incorporation throughout the polymer matrix, preventing the doubly distributed problem.
3Manufacturing precision
If controlled radical polymerization methods are used to prepare polymers with narrow polydispersity, then molecular weight control is improved, but the process complexity increases compared to conventional free radical polymerization
Solution Approach 1:
The patent uses a RAFT agent as an intermediary substance that mediates the polymerization process. This intermediary enables controlled radical polymerization with narrow polydispersity while simplifying the overall process compared to other controlled methods, as the RAFT agent handles the complexity of radical control and polymer chain growth regulation.
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 solution achieves improved PAG dispersion and molecular weight control, resulting in reduced LWR and LER, enhancing the resolution and performance of photoresists in microlithography, particularly at wavelengths of 13.4 nm.
Implementation Method 1
Development of novel chain transfer agents for reversible addition-fragmentation transfer (RAFT) controlled polymerization reactions
Implementation Method 2
photoacid generators (PAGs) for catalyzing deprotection of protected developable groups in photoresist films
Data Source
AI summary
A compound has formula (I):wherein in formula (I), Z is a y valent C1-20 organic group, A1 and A2 are each independently ester containing or non-ester containing and are fluorinated or non-fluorinated, and are independently C1-40 alkylene, C3-40 cycloalkylene, C6-40 arylene, or C7-40 aralkylene, and A1 contains a nitrile, ester, or aryl substituent group alpha to the point of attachment with sulfur, L is a heteroatom or a single bond, X1 is a single bond, —O—, —S—, —C(═O)—O—, —O—C(═O)—, —O—C(═O)—O—, —C(═O)—NR—, —NR—C(═O)—, —NR—C(═O)—NR—, —S(═O)2—O—, —O—S(═O)2—O—, —NR—S(═O)2—, or —S(═O)2—NR, wherein R is H, C1-10 alkyl, C3-10 cycloalkyl or C6-10 aryl, Q− is an anionic group, G+ is a metallic or non-metallic cation, and y is an integer from 1 to 6. A polymer having end groups comprising the reaction product of the compound of formula (I), and a method of making a polymer, are also disclosed.