Photoresist Polymer with Anionic Endgroups for LWR Reduction
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Solution Overview
Problem
Current photoresist compositions face challenges in achieving higher sensitivity and lower Line Width Roughness (LWR) for line/space patterns, which are crucial for advanced semiconductor manufacturing.
Innovation Solution
A polymer is developed with specific repeating units containing an acid labile group, an anionic endgroup such as a carboxylate or sulfamate group, and an organic cation, which is used in a photoresist composition and pattern formation method involving exposure to activating radiation followed by development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photoresist compositions are used, then basic pattern formation is achieved, but sensitivity and Line Width Roughness (LWR) for line/space patterns cannot be improved further
Solution Approach 1:
The patent modifies the chemical parameters of the photoresist composition by incorporating specific polymers with acid-labile groups (such as t-butyl ester groups) that undergo controlled decomposition upon acid generation. This chemical parameter change enables improved sensitivity and reduced LWR by controlling the deprotection and dissolution rates during development
Solution Approach 2:
The patent employs composite photoresist formulations combining multiple components: polymers with acid-labile groups, photoacid generators, and base additives. This composite approach allows synergistic effects where each component contributes specific functions, achieving both high sensitivity and low LWR that cannot be obtained with single-component systems
2Manufacturing precision
If higher integration density and nanometer-range structures are pursued, then resolution requirements increase, but conventional photoresists cannot achieve the required sensitivity and LWR performance
Solution Approach 1:
The patent implements local quality control through acid quenching materials that are strategically distributed in the photoresist composition. These quenchers locally neutralize excess acid in specific regions, preventing unwanted side reactions and maintaining uniform deprotection only in exposed areas, thereby achieving the required resolution for nanometer-scale structures
Solution Approach 2:
The patent incorporates base additives that perform preliminary neutralization of acid before the development step. This preliminary action controls the acid-catalyzed side reactions and pre-establishes the solubility difference between exposed and unexposed regions, enabling higher sensitivity and resolution in subsequent development
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 polymer composition enhances sensitivity and reduces LWR, improving the resolution and precision of pattern formation in semiconductor manufacturing.
Implementation Method 1
Pattern-wise exposure to activating radiation through a photomask causes the acid generator to form an acid which, during post-exposure baking, causes cleavage of the acid-labile groups in exposed regions of the polymer
Implementation Method 2
Acid quenching materials are often added to the photoresist composition for controlling the diffusion of the acid to unexposed region to improve the contrast
Data Source
AI summary
A polymer including a first repeating unit comprising an acid labile group; an anionic endgroup selected from a carboxylate group or a sulfamate group; and an organic cation.