Iodized Benzamide Resist for EUV Sensitivity and LWR
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Solution Overview
Problem
EUV resist materials face a tradeoff between sensitivity and low edge roughness (LWR), with reduced acid diffusion leading to lower sensitivity and increased LWR, and the shorter wavelength and higher energy density of EUV exposure complicating pattern formation.
Innovation Solution
A resist composition using a sulfonium or iodonium salt of an iodized benzamide-containing fluorinated sulfonic acid as an acid generator, which enhances sensitivity and minimizes LWR by promoting acid decomposition and controlling acid diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the acid diffusion distance is reduced to lower LWR, then the sensitivity becomes lower
Solution Approach 1:
The patent changes the chemical structure parameters of the acid generator by introducing iodine atoms at specific positions (using formulas (I-1) to (I-6) with specific R1-R7 groups) to achieve optimal balance between acid diffusion control and sensitivity. The fluorinated sulfonic acid component with benzene ring structure provides controlled acid diffusion while maintaining high sensitivity.
Solution Approach 2:
The acid generator is designed as a composite structure combining iodine-substituted benzene ring, amide group, and fluorinated sulfonic acid components. This composite molecular structure integrates multiple functional elements: iodine for light absorption, amide for acid diffusion control, and fluorinated sulfonic acid for sensitivity enhancement, resolving the contradiction between LWR and sensitivity.
2Manufacturing precision
If the PEB temperature is lowered to reduce LWR, then the sensitivity becomes lower
Solution Approach 1:
The patent modifies the chemical parameters of the acid generator to compensate for lower PEB temperatures. The iodine-substituted fluorinated sulfonic acid structure maintains effective acid generation and diffusion control at reduced temperatures, enabling LWR improvement without sensitivity loss.
3Manufacturing precision
If the amount of quencher added is increased to reduce LWR, then the sensitivity becomes lower
Solution Approach 1:
The patent changes the approach from adding external quenchers to using the acid generator's own molecular structure (iodine-substituted benzene ring with fluorinated sulfonic acid) to control acid diffusion. This intrinsic control mechanism reduces LWR without requiring additional quenchers that would reduce sensitivity.
4Manufacturing precision
If the wavelength is reduced to 13.5 nm for EUV lithography, then the resolution is improved but the photon number available decreases to 1/14 of ArF exposure
Solution Approach 1:
The iodine atoms in the acid generator act as strong light absorbers at EUV wavelength, accelerating the photo-decomposition reaction. The high absorption cross-section of iodine at 13.5 nm compensates for the low photon flux, enabling effective pattern formation despite reduced photon number.
Solution Approach 2:
The patent optimizes the molecular parameters of the acid generator to maximize EUV absorption efficiency. The iodine-substituted benzene ring structure with specific fluorinated groups (formulas (I-1) to (I-6)) provides optimal absorption at 13.5 nm wavelength, converting the low photon number into effective acid generation.
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, minimal LWR, and improved critical dimension uniformity (CDU) across both positive and negative tone patterns, maintaining high contrast and resolution while expanding process margins.
Implementation Method 1
The acid generator is a sulfonium or iodonium salt of an iodized benzamide group-containing fluorinated sulfonic acid... promotes decomposition of the acid generator upon EUV exposure
Implementation Method 2
As the acid diffusion distance is reduced, LWR is reduced, but sensitivity becomes lower
Data Source
AI summary
A resist composition comprising a base polymer and an acid generator containing a sulfonium or iodonium salt of iodized benzamide group-containing fluorinated sulfonic acid offers a high sensitivity, minimal LWR and improved CDU independent of whether it is of positive or negative tone.