Positive Resist Composition Acid Diffusion Control
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Solution Overview
Problem
Existing resist materials for ArF excimer laser lithography face challenges with resolution degradation due to excessive acid movement during post-exposure bake, which affects pattern fidelity and density dependency.
Innovation Solution
A positive resist composition incorporating a polymer with specific recurring units containing non-leaving hydroxyl groups and a sulfonium salt compound as an acid generator, which controls acid diffusion and enhances resolution capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If chemically amplified resist materials are used with acid generators, then deprotection reaction is promoted and pattern formation is enabled, but acid diffusion during post-exposure bake degrades resolution
Solution Approach 1:
The patent introduces a base compound with specific recurring units as an intermediary substance that mediates between the acid generator and the base resin. This base compound contains recurring units with specific structures that control acid diffusion, acting as a buffer to prevent excessive acid movement while still allowing necessary deprotection reactions to proceed.
Solution Approach 2:
The patent changes the chemical parameters of the resist system by incorporating base compounds with specific recurring units that have controlled acid-base reaction characteristics. These recurring units modify the local chemical environment to regulate acid diffusion and reaction rates, enabling precise control over the deprotection process without excessive acid migration.
2Manufacturing precision
If acid movement is controlled to improve resolution, then pattern fidelity is improved, but deprotection reaction efficiency may be reduced
Solution Approach 1:
The patent applies local quality by incorporating base compounds with specific recurring units that create localized controlled environments for acid-base reactions. The recurring units are strategically designed to provide acid diffusion control in specific regions while maintaining overall reaction efficiency, ensuring that acid movement is regulated where needed without compromising overall deprotection performance.
3Reliability
If existing resist materials are used for ArF excimer laser lithography, then transparency and dry etch resistance are achieved, but resolution degradation occurs due to over-diffusion
Solution Approach 1:
The patent employs composite materials by combining the base resin with specific base compounds containing recurring units that have controlled acid diffusion properties. This composite approach maintains the desirable transparency and dry etch resistance of traditional resist materials while adding the acid diffusion control capability through the incorporated base compound, thereby achieving both reliability and precision.
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 resolution and improved pattern density dependency and mask fidelity by effectively managing acid movement, thereby addressing the limitations of previous materials.
Implementation Method 1
a compound capable of generating an acid in response to actinic light or radiation
Implementation Method 2
the acid generated upon exposure triggers deprotection reaction on the base resin which proceeds during heat treatment following exposure (post-exposure bake or PEB)
Implementation Method 3
Movement or diffusion of the acid occurs during PEB
Data Source
AI summary
A positive resist composition comprises (A) a resin component which becomes soluble in an alkaline developer under the action of an acid and (B) an acid generator. The resin (A) is a polymer comprising recurring units containing a non-leaving hydroxyl group represented by formula (1) wherein R1 is H, methyl or trifluoromethyl, m is 1 or 2, and the hydroxyl group attaches to a tertiary carbon atom. The composition is improved in resolution when processed by lithography.