Underlayer Coating Composition for EUV Lithography
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Solution Overview
Problem
Existing photoresist technologies face limitations in achieving high resolution and uniformity due to reflection and scattering of activating radiation, as well as substrate topography variations, leading to pinhole defects in thin underlayer coating layers during thermal treatment.
Innovation Solution
The use of a thin underlayer coating composition comprising a resin and solvents with boiling points of 200°C or greater, such as gamma butyrolactone, N-methyl pyrrolidine, and benzyl benzoate, which reduces pinhole defects when applied as a thin layer and thermally treated, enhancing adhesion and reducing defects in EUV lithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a thin underlayer coating layer is used to reduce reflection and improve resolution, then the resolution and image quality are improved, but pinhole defects occur during thermal treatment
Solution Approach 1:
The patent changes the chemical composition parameters of the underlayer coating by incorporating specific solvents with boiling points of 200°C or greater (such as gamma butyrolactone, N-methyl pyrrolidine, and benzyl benzoate). This parameter change in solvent selection prevents pinhole defect formation during thermal treatment while maintaining the thin film structure needed for high resolution imaging.
2Manufacturing precision
If the thickness of the underlayer coating layer is decreased to improve resolution, then the resolution is improved, but the occurrence of pinhole defects increases
Solution Approach 1:
The patent modifies the compositional parameters of the underlayer coating by introducing solvents with high boiling points (200°C or greater). This allows the use of thinner film thicknesses for improved resolution while the specific solvent chemistry prevents pinhole formation, effectively decoupling the trade-off between thickness and defect formation.
3Ease of manufacture
If conventional solvents are used in the underlayer coating, then the coating process is simple, but pinhole defects occur during thermal treatment
Solution Approach 1:
The patent changes the solvent selection parameter from conventional low-boiling-point solvents to high-boiling-point solvents (200°C or greater) such as gamma butyrolactone, N-methyl pyrrolidine, and benzyl benzoate. This parameter change maintains coating processability while preventing pinhole defects during subsequent thermal treatment steps.
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 solution significantly reduces pinhole defects and improves the uniformity of the photoresist layer, enabling the formation of pinhole-free resist films suitable for Extreme Ultra-Violet (EUV) lithography with reduced thickness, thereby enhancing the resolution and quality of the imaged pattern.
Implementation Method 1
a solvent component comprising one or more solvents having a boiling of 200° C. or greater
Data Source
AI summary
Underlayer coating compositions are provided that comprise 1) a resin; and a solvent component comprising one or more solvents having a boiling of 200° C. or greater. Coating compositions are particularly useful with overcoated photoresist compositions imaged with EUV.