Bisonium Salt Resist Composition for EUV Lithography
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Solution Overview
Problem
Current 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
A resist composition incorporating a bisonium salt with a divalent anion having an arylsulfonate structure linked to an aromatic group with iodine or bromine atoms, and a sulfonimide or sulfonamide anion structure bonded via a linking group, which acts as both an acid generator and quencher, reducing acid diffusion and enhancing sensitivity and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the PEB temperature is lowered to reduce acid diffusion distance, then LWR and CDU are improved, but sensitivity becomes lower
Solution Approach 1:
The patent introduces a quencher component with specific basicity (pKb value range) that creates localized acid neutralization zones near the acid generation sites. This localized action suppresses acid diffusion precisely where needed (improving LWR/CDU) without requiring global temperature reduction (maintaining sensitivity).
Solution Approach 2:
The patent changes the chemical parameter of the resist composition by adding a quencher with specific basicity characteristics. This chemical parameter change enables acid diffusion control without altering the thermal parameter (PEB temperature), thus resolving the contradiction between LWR/CDU improvement and sensitivity maintenance.
2Manufacturing precision
If the amount of quencher added is increased to reduce acid diffusion, then LWR and CDU are improved, but sensitivity becomes lower
Solution Approach 1:
The patent identifies and controls the basicity parameter (pKb value) of the quencher as the critical factor. By specifying an optimal pKb range (0-14 with preferred ranges), the patent achieves effective acid diffusion control with appropriate quencher amounts, avoiding the sensitivity loss that occurs with excessive quencher addition.
Solution Approach 2:
The patent uses a polymer-bound quencher structure that replicates the optimal quencher positioning at multiple locations throughout the resist matrix. This structured distribution ensures uniform acid diffusion control without requiring high overall quencher concentrations, thereby maintaining sensitivity.
3Productivity
If conventional resist composition is used to achieve high sensitivity, then sensitivity is improved, but LWR and CDU deteriorate due to acid diffusion
Solution Approach 1:
The patent merges the acid generator and quencher functions into a coordinated system where the quencher is strategically positioned relative to the acid generator. This merging enables simultaneous achievement of high sensitivity (through efficient acid generation) and low LWR/CDU (through controlled acid diffusion).
Solution Approach 2:
The quencher acts as an intermediary substance between the acid generator and the polymer matrix. It mediates the acid diffusion process by providing localized neutralization, thus enabling high sensitivity from the acid generator while preventing the harmful acid diffusion that would otherwise occur.
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 resist composition exhibits high sensitivity, improved LWR and CDU, high contrast, excellent resolution, and a wide process margin, effectively addressing the tradeoff between sensitivity and acid diffusion control.
Implementation Method 1
the acid generator is directly excited by exposure to radiation
Implementation Method 2
The inclusion of iodine atoms that absorb a large amount of EUV or bromine atoms that are efficiently ionized improves the efficiency of decomposition of the acid generator during exposure
Implementation Method 3
image blurs due to acid diffusion become a problem
Data Source
AI summary
A resist composition comprising a bisonium salt containing a divalent anion having an arylsulfonate anion structure linked to an aromatic group having an iodine atom or a bromine atom and a sulfonimide anion structure or a sulfonamide anion structure bonded to the aromatic group having an iodine atom or a bromine atom, via a linking group having 1 or more carbon atoms, and an onium cation.