Resist Composition with Iodized Benzene Salt for Lithography
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Solution Overview
Problem
As pattern feature sizes decrease, challenges arise in achieving high sensitivity, low line width roughness (LWR), and critical dimension uniformity (CDU) in microelectronic device manufacturing due to reduced light contrast and acid diffusion issues in resist compositions, particularly in ArF and EUV lithography processes.
Innovation Solution
Incorporating a sulfonium or iodonium salt capable of generating a sulfonic acid bonded to an iodized benzene ring, which acts as both an acid generator and quencher, to enhance contrast, reduce LWR, and improve CDU by suppressing acid diffusion and increasing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional acid generators are used in resist compositions, then deprotection reaction occurs under acid action, but acid diffusion to unexposed areas reduces contrast and resolution
Solution Approach 1:
The patent introduces a quencher as an intermediary substance that reacts with diffused acid to neutralize it. The quencher is positioned throughout the resist film to intercept and neutralize acid molecules as they diffuse from exposed to unexposed areas, thereby preventing unwanted deprotection reactions and maintaining sharp pattern boundaries.
Solution Approach 2:
The patent extracts the harmful acid diffusion effect by introducing a dedicated quencher component that specifically targets and neutralizes diffused acid. This separates the useful acid-catalyzed deprotection reaction in exposed areas from the harmful acid diffusion to unexposed areas, allowing independent control of each effect.
2Productivity
If pattern feature size is reduced to increase integration density, then manufacturing capacity increases, but light contrast lowers and resolution margin decreases
Solution Approach 1:
The patent changes the chemical parameters of the resist system by introducing a quencher with specific basicity and reactivity characteristics. This modifies the acid-base reaction dynamics to enhance dissolution contrast, allowing smaller pattern features to be resolved with higher precision even as feature sizes are reduced for increased integration density.
Solution Approach 2:
The patent creates a composite resist system combining the base polymer, acid generator, and quencher components with complementary functions. This composite formulation synergistically enhances both sensitivity and resolution, enabling the resist to maintain manufacturing precision while supporting reduced pattern dimensions for higher productivity.
3Manufacturing precision
If quencher is added to control acid diffusion, then contrast improves, but sensitivity may be reduced due to quencher consuming acid
Solution Approach 1:
The patent applies local quality by creating spatial variation in quencher effectiveness. In exposed areas, the high acid concentration overwhelms the quencher, allowing deprotection to proceed. In unexposed areas, the quencher effectively neutralizes diffused acid. This spatial differentiation maintains high contrast while preserving sensitivity through localized acid-quencher interaction dynamics.
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 with sulfonium or iodonium salts exhibits improved sensitivity, reduced LWR, and enhanced CDU, effectively addressing the limitations of existing resist materials in achieving high resolution and process margin across various lithography processes.
Implementation Method 1
a sulfonium salt having the formula (A-1) and/or an iodonium salt having the formula (A-2) The sulfonium or iodonium salt is capable of generating a sulfonic acid upon light exposure
Implementation Method 2
The sulfonium or iodonium salt capable of generating a sulfonic acid bonded to an iodized benzene ring acts as both an acid generator and quencher
Data Source
AI summary
A resist composition comprising a base polymer and a sulfonium or iodonium salt capable of generating sulfonic acid bonded to iodized benzene ring offers a high sensitivity and minimal LWR independent of whether it is of positive or negative tone.