Positive Resist Composition for EUV Lithography Aging Stability
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Solution Overview
Problem
Conventional positive resist compositions for electron beam and EUV lithography face challenges with aging stability, requiring adjustments in exposure amounts and development conditions over time, which hampers mass production in semiconductor processing.
Innovation Solution
A positive resist composition incorporating a compound that generates an organic acid upon irradiation, featuring a proton acceptor functional group and an acid-decomposable resin to enhance solubility in alkali developers, ensuring consistent performance and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a low-molecular phenol compound is used as the main component to achieve high dissolution contrast, then the dissolution contrast is improved, but the aging stability deteriorates
Solution Approach 1:
The patent uses a copolymer resin composed of multiple monomer units (acid-decomposable monomers with specific functional groups combined with other monomers) to create a composite material structure. This composite approach maintains high dissolution contrast through the acid-decomposable groups while the diverse monomer composition provides aging stability, resolving the contradiction between dissolution contrast and aging stability.
Solution Approach 2:
The patent specifies precise compositional parameters for the copolymer resin, including the ratio of acid-decomposable monomer units (0.1-10 mol%) and specific functional group configurations. By controlling these parameters, the resin achieves optimal balance between dissolution contrast (from acid decomposition) and aging stability (from controlled composition), preventing the instability of low-molecular compounds.
2Productivity
If a conventional resist composition is stored in large amount for mass production, then the productivity is improved, but the sensitivity changes with aging requiring adjustment of exposure conditions
Solution Approach 1:
The patent incorporates a proton acceptor functional group into the resin structure before use, which preemptively counteracts aging effects. This preliminary structural design ensures that the resist maintains consistent sensitivity over storage time, allowing mass production without requiring exposure condition adjustments despite prolonged storage.
Solution Approach 2:
The proton acceptor functional group acts as an internal feedback mechanism that monitors and compensates for aging changes in the resist composition. This built-in compensation system maintains sensitivity consistency during storage, enabling reliable mass production from stored resist materials without requiring external adjustments to exposure conditions.
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 improved aging stability and consistent pattern formation in semiconductor processing, allowing for more reliable and efficient mass production by maintaining sensitivity and resolution over time.
Implementation Method 1
a compound having a proton acceptor functional group and capable of producing an acid radical upon irradiation with an actinic ray or radiation
Data Source
AI summary
A positive resist composition for electron beam, X-ray or EUV includes a compound having a proton acceptor functional group and capable of producing an acid radical upon irradiation with an actinic ray or radiation to reduce or lose the acceptor property or to change the proton acceptor functional group to be acidic, wherein the positive resist composition has a solid content concentration of from 2.5 to 4.5 mass %.