Radiation-Sensitive Resin Composition for Lithography Resolution
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Solution Overview
Problem
Conventional lithography techniques face challenges in achieving sub-0.10 μm microfabrication due to limitations in wavelength and numerical aperture, leading to difficulties in forming finer resist patterns without increasing costs or compromising focal depth.
Innovation Solution
A radiation-sensitive resin composition comprising a first polymer with a specific structure unit and a second polymer with an acid-dissociable group, along with a radiation-sensitive acid generator, is used for liquid immersion lithography, enhancing MEEF performance and inhibiting defects like bridge formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the wavelength of the light source is decreased to enable finer microfabrication, then the resolution is improved, but the exposure system becomes expensive and requires novel equipment
Solution Approach 1:
The patent changes the parameter of the liquid medium's refractive index by using immersion liquid instead of air, which effectively increases the numerical aperture and improves resolution without requiring a shorter wavelength light source, thereby avoiding the need for expensive novel exposure systems
Solution Approach 2:
The patent introduces an intermediary substance (immersion liquid) between the lens and the resist film to modify the optical path and enhance the effective numerical aperture, achieving better resolution with existing equipment
2Manufacturing precision
If the numerical aperture of the lens is increased to improve resolution, then the resolving ability is enhanced, but the focal depth decreases
Solution Approach 1:
The patent changes the refractive index parameter of the medium between the lens and resist film by using immersion liquid, which allows for an increased effective numerical aperture while maintaining favorable focal depth through the optical properties of the immersion medium
3Ease of manufacture
If conventional resist compositions are used for liquid immersion lithography, then the process is simple, but the MEEF performance is insufficient and defects like bridge formation occur
Solution Approach 1:
The patent uses a composite resist composition containing both a carboxylic acid group-containing polymer and a sulfonic acid group-containing polymer, which synergistically improves MEEF performance and reduces defects like bridge formation while maintaining compatibility with liquid immersion lithography processes
Solution Approach 2:
The patent introduces specific functional groups (carboxylic acid and sulfonic acid groups) at local positions within the resist polymer structure to enhance acid diffusion control and improve MEEF performance in critical regions without compromising overall process simplicity
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 enables the formation of finer resist patterns with improved MEEF performance and reduced defects, maintaining favorable focal depth and water repellency, suitable for future miniaturization in lithography techniques.
Implementation Method 1
a component (hereinafter, may be also referred to as 'acid generator') that generates an acid upon irradiation with a radioactive ray (hereinafter, may be also referred to as 'exposure')
Implementation Method 2
a liquid for liquid immersion lithography having a refractive index (n) greater than that of the air and the like; therefore, even if the light of exposure similar to that of a conventional type is used, an effect similar to that achievable when the light of exposure has a shorter wavelength can be achieved
Data Source
AI summary
A radiation-sensitive resin composition includes a first polymer, a second polymer and a radiation-sensitive acid generator. The first polymer has a structure unit represented by a following formula (1-1), a structure unit represented by a following formula (1-2), or both thereof, and has a content of fluorine atoms of no less than 5% by mass to a total mass of the first polymer. The second polymer has an acid-dissociable group, and has a content of fluorine atoms of less than 5% by mass to a total mass of the second polymer.