Iodized Resist Composition Breaks Sensitivity-LWR Tradeoff
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Solution Overview
Problem
EUV lithography faces challenges in achieving high sensitivity, low line width roughness (LWR), and critical dimension uniformity (CDU) due to variations in photon number, which are not adequately addressed by incorporating iodine into resist materials, leading to a tradeoff between sensitivity and LWR.
Innovation Solution
A resist composition comprising an iodized polymer and a quencher selected from sulfonium or ammonium salts of iodized benzene ring-containing carboxylic acid, N-carbonylsulfonamide, or ammonium salt, which effectively controls acid diffusion and enhances sensitivity while reducing LWR and improving CDU.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the amount of quencher added is increased to suppress acid diffusion and reduce LWR, then LWR is reduced, but sensitivity becomes lower
Solution Approach 1:
The patent changes the chemical structure parameters of the quencher by introducing iodine-substituted aromatic rings with specific substituents (R1-R6 groups including electron-withdrawing and electron-donating groups). This structural modification allows the quencher to simultaneously achieve strong acid diffusion suppression (reducing LWR) and maintain high sensitivity by optimizing the balance between quenching efficiency and acid generation efficiency.
Solution Approach 2:
The patent creates a composite quencher structure combining iodine-substituted aromatic rings with various functional groups (carboxylic acid, N-carbonylsulfonamide, ammonium salt). This composite structure integrates multiple functions: iodine atoms provide strong acid diffusion suppression, while the aromatic ring system and substituents maintain appropriate quenching activity, achieving both low LWR and high sensitivity.
2Shape
If PEB temperature is lowered to reduce LWR, then LWR is reduced, but sensitivity becomes lower
Solution Approach 1:
The patent modifies the chemical parameters of the quencher (introducing iodine-substituted aromatic structures with specific substituents) to change the acid diffusion characteristics. This allows LWR reduction through chemical means rather than thermal means, enabling low LWR without the sensitivity penalty associated with lower PEB temperatures.
3Productivity
If iodine is incorporated to increase photon absorption and sensitivity, then sensitivity is improved, but LWR becomes degraded due to insufficient acid diffusion control
Solution Approach 1:
The patent creates a composite quencher structure where iodine-substituted aromatic rings are combined with specific functional groups (carboxylic acid, N-carbonylsulfonamide, ammonium salt). The iodine atoms provide strong photon absorption for high sensitivity, while the aromatic ring system with electron-withdrawing and electron-donating groups provides effective acid diffusion suppression, achieving both high sensitivity and low LWR simultaneously.
Solution Approach 2:
The patent introduces local quality variations by placing different substituents (R1-R6 including electron-withdrawing and electron-donating groups) at specific positions on the aromatic ring. This local modification optimizes the balance between quenching efficiency and acid diffusion suppression at different molecular locations, achieving both high sensitivity and low LWR.
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 achieves high sensitivity, low LWR, and improved CDU, breaking the tradeoff between these parameters, and is effective for both positive and negative tone pattern formation.
Implementation Method 1
Among the halogen atoms, iodine is highly absorptive to EUV radiation of wavelength 13.5 nm
Implementation Method 2
Since iodine has a large atomic weight, quenchers in the form of iodized compounds are fully effective for suppressing acid diffusion
Implementation Method 3
the acid generation efficiency of iodized styrene is only 14% of that of hydroxystyrene
Data Source
AI summary
A resist composition comprising an iodized base polymer and an iodized benzene ring-containing quencher has a high sensitivity and improved LWR and CDU.