Positive Resist Composition Acid Diffusion Control
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Solution Overview
Problem
Current chemically amplified positive resist compositions face challenges in achieving high sensitivity, resolution, and minimal edge roughness, particularly with the increasing accelerating voltage in electron beam lithography, which leads to reduced sensitivity and contrast due to acid diffusion issues.
Innovation Solution
A positive resist composition is developed, comprising a polymer with acid labile groups and a sulfonium or iodonium salt of specific cation structure capable of generating a bulky acid, blending these components to minimize acid diffusion and enhance sensitivity and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the accelerating voltage is increased to enable further size reduction, then the resolution and dimensional control are improved, but the sensitivity of the resist film becomes lower
Solution Approach 1:
The patent changes the chemical parameters of the resist composition by introducing a chemically amplified positive resist system with specific polymer components and acid generators. This allows the resist to respond more effectively to electron beam exposure at high voltages, maintaining sensitivity while achieving the required resolution for further size reduction.
Solution Approach 2:
The patent uses a composite resist composition comprising multiple components including polymer (a) with specific functional groups, polymer (b) as a base resin, and acid generators. This composite structure enables the resist to simultaneously achieve high sensitivity and high resolution by combining the functions of different materials.
2Productivity
If chemically amplified resist compositions are designed to enhance sensitivity and contrast through acid diffusion, then the sensitivity is improved, but image blurs due to acid diffusion become a problem
Solution Approach 1:
The patent applies local quality control by using a base resin with specific glass transition temperature characteristics and incorporating acid generators that produce localized acid diffusion. The polymer composition is designed to have different functional regions that control acid diffusion locally, ensuring high sensitivity while preventing image blurring.
Solution Approach 2:
The patent carefully controls the glass transition temperature of the base resin and the molecular weight of the polymer to optimize acid diffusion characteristics. By adjusting these parameters, the resist achieves enhanced sensitivity through controlled acid diffusion while maintaining sharp pattern definition and preventing image blurring.
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 composition achieves high sensitivity, satisfactory pattern profiles, and reduced line edge roughness, making it suitable for advanced lithography processes such as EUV and EB lithography.
Implementation Method 1
a sulfonium salt and/or iodonium salt having a specific cation structure and capable of generating an acid having a molecular weight of at least 540
Implementation Method 2
image blurs due to acid diffusion become a problem
Data Source
AI summary
A positive resist composition is provided comprising a polymer having an acid labile group and an acid generator bound to its backbone, in admixture with an onium salt having a specific cation structure capable of generating sulfonic acid having a molecular weight of at least 540. The composition is effective for suppressing acid diffusion, has high resolution, and forms a pattern of satisfactory profile and minimal edge roughness after exposure and development.