Fluorinated Polymer Resist Composition for ArF Lithography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
ArF resist materials face challenges with increased line edge roughness and reduced etching resistance compared to KrF resists, despite advancements in lithography techniques such as higher numerical aperture and wavelength reduction.
Innovation Solution
A fluorinated polymer with specific recurring units is developed through radical polymerization, forming a chemically amplified resist composition that is transparent to wavelengths up to 200 nm, offering improved etch resistance and minimal line edge roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If poly(meth)acrylate resins are used as base resin for ArF lithography, then ease of manufacture is improved, but line edge roughness increases and etching resistance decreases
Solution Approach 1:
The patent uses a composite polymer structure combining norbornene units (providing etching resistance and structural stability) with polymethacrylate units (providing ease of manufacture and solubility). This composite approach allows the resist to achieve both manufacturability and high manufacturing precision by leveraging the complementary properties of different polymer units.
Solution Approach 2:
The patent modifies the chemical structure of the base resin by introducing specific fluorinated groups and controlling the molecular weight and composition ratios. These parameter changes in the polymer structure improve etching resistance and reduce line edge roughness while maintaining the ease of polymerization characteristic of poly(meth)acrylate resins.
2Strength
If polyhydroxystyrene resins are used for KrF lithography, then etching resistance is improved, but transparency to 193 nm light is reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the base resin by using norbornene and polymethacrylate units instead of polyhydroxystyrene. This parameter change maintains etching resistance while improving transparency to 193 nm ArF laser light, enabling the resist to work effectively at the shorter wavelength.
Solution Approach 2:
The patent introduces specific functional groups at localized positions within the polymer chain - fluorinated groups for etching resistance and specific adhesive groups for controlled solubility. This local quality approach allows different parts of the molecule to provide different functions, achieving both etching resistance and light transparency.
3Measurement precision
If wavelength is reduced from KrF (248 nm) to ArF (193 nm), then resolution is improved, but line edge roughness increases
Solution Approach 1:
The patent employs a composite polymer system that combines the benefits of different polymer units to achieve high resolution with minimal line edge roughness. The norbornene units provide structural integrity and etching resistance, while the polymethacrylate units provide good solubility and uniform dissolution, resulting in smooth pattern edges even at the higher resolution of 193 nm lithography.
Solution Approach 2:
The patent creates a resist system that accurately copies the mask pattern with minimal distortion or roughness. The specially designed polymer structure ensures faithful pattern transfer from mask to wafer, maintaining manufacturing precision even as resolution increases through wavelength reduction.
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 demonstrates enhanced resolution, reduced line edge roughness, and improved etching resistance, particularly in ArF immersion lithography, with better performance compared to traditional ArF resist materials.
Implementation Method 1
a photoacid generator which undergoes photolysis by laser light having a wavelength of 193 nm or 248 nm
Implementation Method 2
A fluorinated polymer with specific recurring units is developed through radical polymerization
Data Source
AI summary
A fluorinated polymer comprising recurring units of formulae (1a) to (1d) and having a Mw of 1,000-500,000 is provided. R1 is an acid labile group, R2 is a single bond or methylene, a1, a2, a3, and a4 are numbers from more than 0 to less than 1, and 0<a1+a2+a3+a4≦1, b is 1 or 2, and c is 0 or 1. A resist composition comprising the polymer, when processed by the lithography involving ArF exposure, has many advantages including resolution, line edge roughness, etch resistance