Negative Resist Composition for Acid Diffusion and Low LER
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Solution Overview
Problem
Existing chemically amplified resist compositions face challenges in achieving high resolution, reduced line edge roughness (LER), and forming patterns with high fidelity, particularly in the miniaturization processes required for semiconductor manufacturing, especially for ArF excimer laser lithography.
Innovation Solution
Incorporation of an onium salt consisting of a sulfonic acid anion with an aromatic sulfonic acid structure and a triarylsulfonium cation containing iodine and fluorine as an acid generator, along with a specific base polymer, to control acid diffusion and enhance pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional chemically amplified resist compositions are used for miniaturization processes, then existing pattern formation capability is maintained, but resolution and line edge roughness (LER) performance are insufficient
Solution Approach 1:
The patent changes the chemical parameters of the acid generator by using an onium salt with a specific structure (sulfonic acid anion with aromatic sulfonic acid structure and triarylsulfonium cation containing iodine and fluorine). This parameter change in the acid generator's molecular structure controls acid diffusion behavior, thereby improving resolution and reducing LER without sacrificing pattern formation reliability
Solution Approach 2:
The patent creates a composite resist composition system combining the specific onium salt acid generator with a base polymer and other resist components. This composite material approach allows synergistic effects where the onium salt's controlled acid diffusion works together with the polymer matrix to achieve both high resolution and low LER, resolving the contradiction between precision and reliability
2Manufacturing precision
If acid diffusion is not controlled, then pattern formation is simplified, but resolution and LER performance deteriorate
Solution Approach 1:
The patent achieves acid diffusion control by changing the inherent parameters of the acid generator molecule itself (using onium salt with specific aromatic sulfonic acid structure and iodine/fluorine substitution). This molecular-level parameter change provides built-in diffusion control without requiring additional complex control mechanisms, thereby improving resolution while maintaining relatively simple device structure
Solution Approach 2:
The onium salt acts as an intermediary substance that mediates between the exposure process and the crosslinking reaction. Its specific molecular structure serves as a built-in diffusion barrier, controlling acid propagation without requiring external control mechanisms, thus improving resolution without significantly increasing device complexity
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 improved resolution, reduced LER, and forms patterns with high fidelity, including dot patterns with rectangular profiles, by effectively controlling acid diffusion and adhesion to the substrate.
Implementation Method 1
an acid generator which is decomposed to generate an acid upon exposure to light
Implementation Method 2
Most often a quencher is added for controlling the diffusion of the acid generated upon light exposure
Data Source
AI summary
An onium salt consisting of a sulfonic acid anion having an aromatic sulfonic acid structure substituted with an aromatic ring-containing hydrocarbyl group and a triarylsulfonium cation containing iodine and fluorine generates an acid having a moderate acidity and limited diffusion. A chemically amplified negative resist composition comprising the onium salt as an acid generator and a polymer is processed by lithography to form a pattern with reduced LER or a dot pattern of rectangular profile.