Alternating Copolymer Photoresists for EUV Lithography
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Solution Overview
Problem
High-resolution EUV lithography requires positive photoresists with improved compositional uniformity to minimize stochastic effects from material variability, as current next-generation resists often rely on negative resists or additional chemical amplifiers.
Innovation Solution
Development of alternating copolymers with EUV-absorbing elements, such as Sn, Te, or Bi, that undergo chain scission upon EUV radiation exposure, eliminating the need for minority components like chemical amplifiers, and incorporating unreactive terminal units to control polymer chain lengths and prevent inter-chain reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If negative resists or chemical amplifiers are used to achieve high-resolution patterning, then patterning capability is improved, but compositional uniformity deteriorates and stochastic effects increase
Solution Approach 1:
The patent removes chemical amplifiers and minority components from the resist composition, using only EUV-absorbing monomer units and organic monomer units in alternating copolymer structure. This extraction of problematic components eliminates the source of compositional variability while maintaining high-resolution patterning capability through direct EUV-induced chain scission
Solution Approach 2:
The patent changes the chemical composition parameters by using alternating copolymer structures with specific EUV-absorbing elements (Sn, Te, Bi, or Sb) combined with organic monomer units. This parameter change achieves both high EUV absorption efficiency and improved compositional uniformity, resolving the contradiction between patterning resolution and compositional stability
2Stability of the object's composition
If alternating copolymer structure with EUV-absorbing elements is used, then compositional uniformity is improved, but EUV absorption efficiency may worsen without proper monomer selection
Solution Approach 1:
The patent creates a composite material system by alternating EUV-absorbing monomer units (containing Sn, Te, Bi, or Sb) with organic monomer units in a copolymer structure. This composite approach ensures both compositional uniformity through regular alternation and high EUV absorption efficiency through the presence of high-Z EUV-absorbing elements at controlled intervals
Solution Approach 2:
The patent applies local quality by concentrating EUV-absorbing elements at specific positions within the alternating copolymer structure, where they are regularly spaced to ensure uniform EUV absorption throughout the resist material while maintaining overall compositional uniformity
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 provides positive photoresists with reduced compositional variability and enhanced EUV absorption efficiency, reducing stochastic errors and achieving higher patterning accuracy without the need for additional chemical components.
Implementation Method 1
repeat units with at least one EUV-absorbing monomer unit
Implementation Method 2
undergo chain scission upon EUV radiation exposure
Data Source
AI summary
Alternating copolymers having hydrocarbon-substituted terminal units and repeat units each containing two different monomer units with extreme ultraviolet (EUV)-absorbing elements are disclosed. Alternating copolymers having organic terminal units and repeat units each containing a monomer unit with an EUV-absorbing element and an organic monomer unit are also disclosed. A process of forming a polymer resist, which includes providing an alternating copolymer having repeat units with at least one EUV-absorbing monomer unit and replacing end groups of the alternating copolymer with unreactive terminal units, is disclosed as well.