Segmented Photoacid Generator Polymers for EUV Lithography
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Solution Overview
Problem
Current photoresists face challenges in achieving high sensitivity, resolution, and low line edge roughness (LER) for sub-30 nm feature formation in EUV and e-beam lithography, due to limitations in acid generation efficiency and diffusion, leading to trade-offs between patterning features and sensitivity.
Innovation Solution
Development of polymers with monomeric photoacid generators covalently attached to the polymer backbone, specifically sulfonium or iodonium salts with polymerizable sulfonate anions, which enhance acid generation efficiency and control acid diffusion, allowing for high-resolution and sensitive photoresist compositions suitable for deep-ultraviolet, extreme-ultraviolet, and electron-beam radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If catalytic chain length is increased to enhance sensitivity, then photospeed is improved, but resolution blur occurs
Solution Approach 1:
The patent segments the photoacid generator into multiple independent units covalently attached to the polymer backbone, replacing a single long-chain catalyst with multiple discrete catalytic sites. This segmentation maintains high photospeed through multiple active sites while preventing resolution blur by localizing acid generation to specific positions along the polymer chain, thereby controlling acid diffusion paths.
Solution Approach 2:
The patent transitions from a linear chain structure to a three-dimensional polymer backbone with pendant photoacid generator units. This dimensional change allows the catalyst to be distributed throughout the polymer matrix in multiple spatial dimensions, enhancing photospeed through increased catalytic sites while maintaining resolution by distributing acid generation events across different spatial locations rather than concentrating them in a single diffusion path.
2Reliability
If acid diffusion is increased to smooth initial acid distribution, then line edge roughness is reduced, but resolution blur increases
Solution Approach 1:
By segmenting the photoacid generator into multiple discrete units attached at different positions on the polymer backbone, the patent creates multiple localized acid generation sites. This segmentation enables controlled acid diffusion where each segment contributes to smoothing local roughness while the distributed nature of segments prevents excessive long-range diffusion that would cause resolution blur.
Solution Approach 2:
The patent implements local quality by positioning photoacid generator segments at specific locations along the polymer chain, creating zones of controlled acid generation. Each local segment provides acid diffusion to smooth its immediate vicinity (reducing LER), while the overall distribution of segments across the polymer maintains global resolution by preventing concentration of diffusion effects in any single region.
3Reliability
If exposure dose is increased to suppress line edge roughness, then LER is reduced, but sensitivity decreases
Solution Approach 1:
The patent changes the fundamental parameter of acid generation efficiency by using covalently attached photoacid generator segments that provide enhanced catalytic activity per unit of absorbed energy. This parameter change allows the system to achieve effective acid distribution and LER control at lower exposure doses, thereby maintaining sensitivity while suppressing line edge roughness through the improved efficiency of the segmented catalyst architecture.
4Reliability
If base quencher loading is increased to suppress line edge roughness, then LER is reduced, but sensitivity decreases
Solution Approach 1:
The patent changes the acid generation parameter through covalent attachment of photoacid generator segments to the polymer backbone, creating a more efficient and stable catalytic system. This parameter change reduces the need for high base quencher loading to control LER, as the segmented architecture provides inherent control over acid distribution and diffusion, thereby maintaining sensitivity while achieving low LER.
Data Source
AI summary
Provided are radiation-sensitive polymers and compositions which may be used in photolithographic processes. The polymers and compositions provide enhanced sensitivity to activating radiation.