Top Anti-Reflection Coating for ArF Lithography
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Solution Overview
Problem
In photolithographic processes for manufacturing flat panel displays and semiconductor devices, the high reflectance of substrates causes light reflection issues, leading to pattern defects and standing-wave effects, especially when using shorter wavelengths, and existing top anti-reflection coatings with low refractive indices are difficult to formulate and expensive to produce.
Innovation Solution
A pattern formation method using a top anti-reflection coating composition comprising a naphthalene compound, a polymer, and a solvent, which absorbs light in the 160 to 260 nm range, exhibiting anomalous dispersion and achieving a low refractive index, thereby reducing standing-wave effects and allowing for the formation of precise patterns at a lower cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a top anti-reflection coating is formed using highly fluorinated polymer materials to achieve a low refractive index, then the refractive index is reduced, but the material cost increases significantly
Solution Approach 1:
The invention changes the chemical composition parameters of the top anti-reflection coating by incorporating naphthalene compounds with specific molecular structures (formula I) that have absorption characteristics in the 160-260nm wavelength range. This parameter change enables the coating to achieve a refractive index of 1.40 to 1.50 at 193nm wavelength without requiring expensive highly fluorinated polymer materials, thus resolving the contradiction between achieving low refractive index and controlling material cost
Solution Approach 2:
The invention creates a composite top anti-reflection coating composition that combines naphthalene compounds (as the active optical component), polymers (as the binder matrix), and solvents. This composite approach allows the naphthalene compound to provide the desired low refractive index through its anomalous dispersion characteristics while the polymer matrix provides structural integrity, achieving both optical performance and cost-effectiveness
2Manufacturing precision
If light of shorter wavelength is used in the exposure step to form a finer pattern, then the pattern resolution is improved, but the standing-wave effect and light reflection problems are exacerbated
Solution Approach 1:
The invention converts the harmful standing-wave effect caused by light reflection into a beneficial outcome by designing a top anti-reflection coating that utilizes anomalous dispersion. The naphthalene compound in the coating has strong light absorption in the 160-260nm range, which creates a drastic change in refractive index that counteracts the standing-wave effect, allowing shorter wavelength light to be used for finer pattern formation without the harmful corrugation effects
Solution Approach 2:
The invention changes the optical parameters of the top anti-reflection coating by selecting naphthalene compounds with specific absorption characteristics in the 160-260nm wavelength range. This parameter change enables the coating to exhibit anomalous dispersion that reduces the standing-wave effect, allowing the use of shorter wavelength exposure light to achieve finer pattern resolution without the harmful effects of light reflection and standing waves
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 method effectively reduces standing-wave effects and achieves the desired pattern precision while forming a top anti-reflection coating with a refractive index of 1.40 to 1.50, even at short wavelengths, and is cost-effective by using a naphthalene compound and fluorinated polymers.
Implementation Method 1
it is studied to make the anti-reflection coating have absorption at a particular wavelength so as to obtain preferred effects by use of anomalous dispersion
Implementation Method 2
The top anti-reflection coating reduces interference of light caused by thickness variation of the resist layer
Implementation Method 3
light having passed through the resist layer is often reflected by the substrate and then reenters the resist layer again
Data Source
AI summary
The present invention provides a composition for forming a top anti-reflection coating having such a low refractive index that it can be suitably used in pattern formation with an ArF excimer laser beam, and further the invention also provides a pattern formation method employing that composition. The top anti-reflection coating composition comprises a particular naphthalene compound, a polymer, and a solvent. The composition is used for forming a top anti-reflection coating provided on a photoresist layer. From the photoresist layer, a pattern can be formed by use of light in 160 to 260 nm.