Chemically Amplified Resist Composition Acid Diffusion Control
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Solution Overview
Problem
Current chemically amplified resist compositions face challenges in achieving rectangular profile patterns with improved line edge roughness (LER), resolution, fidelity, and dose margin due to uncontrolled acid diffusion, particularly in EUV and EB lithography processes.
Innovation Solution
A chemically amplified positive resist composition incorporating a quencher with an onium salt containing a nitrogen-containing aliphatic heterocycle and an aromatic carboxylic acid structure, which effectively controls acid diffusion and enhances the solubility of the base polymer in alkaline developers, leading to improved pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acid-decomposable protective groups requiring low activation energy (such as acetal groups) are used, then resist sensitivity is improved, but acid diffusion control deteriorates causing deprotection in unexposed regions and reduced pattern quality
Solution Approach 1:
A base polymer is introduced as an intermediary substance that binds to generated acid through acid-base interaction. This base polymer acts as a mediator that controls acid diffusion by sequestering the acid in the exposed region, preventing it from diffusing to unexposed regions and causing unwanted deprotection. The base polymer thus enables the use of low-energy deprotection groups while maintaining pattern quality.
Solution Approach 2:
The invention changes the chemical environment parameters by introducing a base polymer that alters the local pH and acid concentration distribution. This parameter change enables precise control over the deprotection reaction, allowing it to occur only in exposed regions where acid is generated, while preventing diffusion to unexposed regions.
2Device complexity
If conventional photoacid generators are used, then resist composition is simple, but acid diffusion is uncontrolled leading to poor resolution and increased LER
Solution Approach 1:
The invention creates a composite resist composition by combining a base polymer with specific functional groups (carboxyl, hydroxyl, or amine) and a photoacid generator. This composite structure enables controlled acid diffusion through the synergistic interaction between the base polymer and the generated acid, achieving improved resolution and reduced LER while maintaining reasonable composition complexity.
3Device complexity
If acid diffusion is not controlled, then resist composition is simple, but deprotection occurs in unexposed regions causing lowered LER and degraded CDU
Solution Approach 1:
The base polymer serves as an intermediary that controls acid diffusion through acid-base interaction. It binds to the generated acid in the exposed region, creating a localized acid reservoir that prevents diffusion to unexposed regions. This intermediary mechanism achieves precise pattern definition without requiring complex additional components.
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, high-fidelity patterns with reduced LER and improved dose margin, effectively addressing the limitations of existing resist compositions by controlling acid diffusion and enhancing pattern rectangularity.
Implementation Method 1
Upon exposure to high-energy radiation, the acid-decomposable protective group is deprotected by the catalysis of an acid generated from a photoacid generator
Implementation Method 2
the polymer may turn soluble in alkaline developer
Data Source
AI summary
A chemically amplified positive resist composition is provided comprising (A) a quencher containing an onium salt having a nitrogen-containing aliphatic heterocycle and an aromatic carboxylic acid structure in its anion and (B) a base polymer containing a specific polymer which is decomposed under the action of acid to increase its solubility in alkaline developer. The resist composition exhibits a high resolution during pattern formation and forms a pattern of rectangular profile with improved LER, fidelity and dose margin.