Bis-onium Salt Resist Composition for EUV Lithography
Solution Overview
Problem
Current EUV lithography resist compositions face challenges in achieving high sensitivity while maintaining low line width roughness (LWR) and critical dimension uniformity (CDU), due to the tradeoff between sensitivity and acid diffusion control.
Innovation Solution
The use of a bis-onium salt as the acid generator and quencher, comprising a divalent anion with a sulfonic acid structure bonded to an iodized aromatic group and a sulfonimide or sulfonamide anion structure, which controls acid diffusion and enhances sensitivity and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the PEB temperature is lowered to reduce acid diffusion, then LWR or CDU is improved, but sensitivity becomes lower
Solution Approach 1:
The patent changes the chemical parameters of the acid generator and quencher by introducing fluorinated aromatic rings and specific substituents. This chemical parameter change allows the system to achieve both low acid diffusion (improved LWR) and high sensitivity simultaneously, resolving the tradeoff between these two parameters.
Solution Approach 2:
The patent uses a composite acid generator system comprising a fluorinated aromatic compound with specific substituents that act as both acid generator and quencher. This composite molecular structure enables simultaneous control of acid diffusion and maintenance of high sensitivity, overcoming the limitation of conventional separate PAG and PDQ systems.
2Manufacturing precision
If the amount of quencher added is increased to control acid diffusion, then LWR or CDU is improved, but sensitivity becomes lower
Solution Approach 1:
The patent merges the acid generator and quencher into a single integrated fluorinated aromatic compound structure. This combination eliminates the need to separately adjust quencher amount, as the molecular structure itself provides both acid generation and quenching functions with optimal balance, thereby maintaining high sensitivity while achieving improved CDU.
Solution Approach 2:
The patent modifies the chemical structure parameters by introducing fluorinated aromatic rings with specific substituents that create an intrinsic quenching effect. This structural parameter change allows the acid generator to self-regulate acid diffusion without requiring additional quencher, thus maintaining high sensitivity while improving CDU.
3Reliability
If chemically amplified resist compositions are designed to enhance sensitivity and contrast by acid diffusion, then sensitivity is improved, but image blurs due to acid diffusion
Solution Approach 1:
The patent changes the chemical parameters by using a fluorinated aromatic acid generator with specific substituents that reduce acid diffusion while maintaining high sensitivity. This parameter change allows the system to achieve both high sensitivity and high resolution simultaneously, overcoming the traditional tradeoff.
Solution Approach 2:
The patent converts the harmful effect of acid diffusion into a beneficial controlled process by using the fluorinated aromatic structure to create a self-limiting diffusion pattern. The same molecular structure that generates acid also controls its diffusion, turning the potential harm of diffusion into a beneficial feature that improves resolution while maintaining sensitivity.
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
This approach results in a resist composition with high sensitivity, reduced LWR, improved CDU, high contrast, and a wide process margin, effectively addressing the tradeoff issues in existing technologies.
Implementation Method 1
the efficiency of decomposition of the acid generator during exposure is increased, leading to a higher sensitivity
Implementation Method 2
Since iodine having high EUV absorption or bromine having high ionization efficiency is included, the efficiency of decomposition of the acid generator during exposure is increased
Implementation Method 3
control of acid diffusion is also important as reported in Non-Patent Document 1
Data Source
AI summary
A resist composition is provided comprising a bis-onium salt consisting of a divalent anion having a sulfonic acid anion structure directly bonded to an iodized aromatic group and a sulfonimide or sulfonamide anion structure bonded to the aromatic group directly or via a linking group, and onium cations. It exhibits a high sensitivity and forms a pattern with reduced LWR or improved CDU independent of whether it is of positive or negative type.