Negative Resist Composition for High-Resolution EUV Patterning
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Solution Overview
Problem
Existing negative resist materials face challenges in achieving high sensitivity and resolution in EUV lithography due to acid diffusion and shot noise, leading to image blurring and critical dimension uniformity issues, while chemically amplified resist compositions suffer from sensitivity and contrast loss when acid diffusion is suppressed.
Innovation Solution
A non-chemically amplified resist composition combining a hypervalent iodine compound with at least two acyloxy groups and a carboxylic acid compound, used with an appropriate developer, to form a robust resist film that exhibits high sensitivity and resolution in electron beam and EUV lithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If acid diffusion is suppressed by lowering PEB temperature or shortening PEB time to ensure resolution for small size patterns, then manufacturing precision is improved, but sensitivity and contrast are remarkably lowered
Solution Approach 1:
The invention changes the chemical parameters of the resist composition by incorporating specific compounds (carboxylic acid compound with formula (1), compound with formula (2), and compound with formula (3)) that modify the acid diffusion characteristics and reaction efficiency, enabling high sensitivity and contrast while maintaining resolution through controlled acid diffusion
Solution Approach 2:
The invention uses a composite resist composition containing multiple specific compounds working together: a carboxylic acid compound as the base resin, a compound with specific functional groups as a crosslinking agent, and a photobase generator, creating a synergistic system that achieves both high resolution and high sensitivity
2Reliability
If chemically amplified resist composition is used to increase sensitivity and contrast through acid diffusion, then reliability is improved, but manufacturing precision deteriorates due to image blurring
Solution Approach 1:
The invention optimizes the molecular weight and chemical structure parameters of the carboxylic acid compound to control acid diffusion length, and adjusts the crosslinking density through the compound of formula (2) to maintain pattern fidelity while enabling sufficient acid diffusion for high sensitivity
Solution Approach 2:
The invention creates local crosslinked structures through the compound of formula (2) that restrict acid diffusion to localized regions around exposed areas, preventing broad image blurring while still allowing enough diffusion for high contrast development
3Manufacturing precision
If negative resist materials like PMMA or HSQ are used to achieve high resolution with no acid diffusion blurring, then manufacturing precision is improved, but reliability deteriorates due to insufficient sensitivity and shot noise effects
Solution Approach 1:
The invention replaces the purely physical crosslinking mechanism of traditional negative resists with a chemical crosslinking mechanism using the compound of formula (2) that reacts with the carboxylic acid compound, enabling controlled crosslinking density that enhances sensitivity while maintaining the no-acid-diffusion advantage for high resolution
Solution Approach 2:
The invention changes the crosslinking kinetics parameters by using the specific compound of formula (2) that provides optimal reaction rate and crosslinking density, significantly improving sensitivity compared to traditional negative resists while maintaining high resolution through controlled crosslinking
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 process achieves high sensitivity and resolution with reduced shot noise, enabling precise micropatterning and minimizing image blur, outperforming conventional materials in terms of solubility and defect levels.
Implementation Method 1
introduction of an element having large absorption of EUV light has attracted attention. Patent Document 1 proposes a chemically amplified resist composition containing an iodine atom that absorbs a large amount of EUV light.
Implementation Method 2
Hydrogensilsesquioxane (HSQ) is a negative resist material that becomes insoluble in an alkaline developer by crosslinking due to a condensation reaction of silanol generated by EUV irradiation.
Implementation Method 3
developing the exposed resist film using a developer that dissolves an unexposed portion and does not dissolve an exposed portion
Data Source
AI summary
A negative resist pattern forming process, comprising: (i) forming a resist film on a substrate using a resist composition containing a hypervalent iodine compound, a carboxylic acid compound, and a solvent; (ii) exposing the resist film with a high-energy radiation; and (iii) developing the exposed resist film using a developer that dissolves an unexposed portion and does not dissolve an exposed portion.