Zinc Tetranuclear Cluster Resist for Low-LWR EUV Patterning
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Solution Overview
Problem
Existing resist compositions face challenges in achieving high sensitivity, resolution, and low line width roughness (LWR) in high-energy ray lithography, particularly in EUV lithography, due to issues like acid diffusion, shot noise, and material stability, which affect critical dimension uniformity and line width roughness, leading to potential transistor failures.
Innovation Solution
A resist composition containing a zinc tetranuclear cluster as the principal component, which absorbs high-energy rays effectively, and includes optional photoacid generators, carboxylic acid compounds, radical scavengers, and surfactants to enhance sensitivity, resolution, and stability, forming a non-chemically amplified resist film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If acid diffusion is suppressed by lowering PEB temperature or shortening PEB time, then resolution is improved, but sensitivity and contrast are remarkably lowered
Solution Approach 1:
The patent changes the fundamental parameter of acid generation by using a zinc tetranuclear cluster that generates bulky acid instead of conventional small acid generators. This parameter change allows acid diffusion to be suppressed while maintaining sensitivity and contrast, as the bulky acid has limited mobility in the resist matrix
Solution Approach 2:
The patent employs a composite material system consisting of the zinc tetranuclear cluster core with organic ligands (R1-R6 groups) attached. This composite structure enables the acid generator to produce bulky acid that suppresses diffusion while maintaining the chemical amplification effect for high sensitivity
2Reliability
If inorganic resist composition with high EUV light absorption is used, then sensitivity is improved, but storage stability and solubility are insufficient
Solution Approach 1:
The patent creates a composite material that combines the high EUV absorption capability of inorganic zinc clusters with the solubility and stability characteristics of organic ligands. The zinc tetranuclear cluster core provides high EUV absorption for improved sensitivity, while the organic ligand shell ensures storage stability and appropriate solubility in resist formulations
Solution Approach 2:
The patent applies local quality by differentiating the functions of different parts of the acid generator: the zinc cluster core handles EUV absorption and acid generation, while the organic ligands handle solubility and stability. This local functional differentiation resolves the contradiction between sensitivity and stability
3Manufacturing precision
If conventional negative resist materials like HSQ are used, then resolution and edge roughness are improved, but sensitivity is insufficient
Solution Approach 1:
The patent changes the molecular size parameter of the acid generator from small (conventional) to bulky (zinc tetranuclear cluster). This parameter change suppresses acid diffusion to achieve low edge roughness and high resolution, while the chemical amplification mechanism maintains high sensitivity
Solution Approach 2:
The patent replaces the physical crosslinking mechanism of HSQ with a chemical amplification mechanism using the zinc tetranuclear cluster. This substitution allows sensitivity to be enhanced through chemical amplification while maintaining the diffusion suppression needed for high resolution
Data Source
AI summary
The resist composition is excellent in sensitivity, resolution, and LWR and is stable and easy to handle in photolithography using a high-energy ray, and a pattern forming method using the resist composition. The resist composition contains a zinc tetranuclear cluster, which was found that it contributes high sensitivity, excellent resolving power and LWR, thereby providing a resist film having excellent stability, which is effective for precise fine processing.