Blankmask Light-Shielding Layer for High-Resolution Lithography
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Solution Overview
Problem
Conventional blankmasks for hardmask technology face challenges in forming thin resist films and light-shielding layers with high resolution and pattern fidelity, as the etch rate of hard mask films is long and the light-shielding layer's thickness is difficult to achieve due to the need for optical density, chemical resistance, and defect repair margin.
Innovation Solution
A blankmask with a thin light-shielding layer and a hard mask film made of materials like tin, chromium, and their compounds, which have a controlled etch rate, allowing for the formation of high-resolution patterns with improved critical dimension features and pattern fidelity, and a photomask manufacturing method involving sequential stacking and etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the resist film thickness is reduced to improve resolution, then the pattern resolution is improved, but the etching time of the hard mask film becomes relatively long
Solution Approach 1:
The patent changes the material composition parameters of the hard mask film by introducing a silicon oxide layer with specific thickness (5-50 nm) and compositional ratios. This parameter change enables the hard mask film to achieve both short etching time and high resolution by optimizing the etch rate through controlled silicon oxide content while maintaining the desired resist film thickness.
Solution Approach 2:
The patent uses a composite hard mask film structure combining silicon oxide with other materials to create a multi-layer configuration. This composite approach allows the hard mask film to exhibit both fast etching speed and high selectivity, resolving the contradiction between reduced etching time and maintained resolution.
2Manufacturing precision
If the light-shielding layer thickness is reduced to improve resolution, then the pattern resolution is improved, but the chemical resistance and defect repair margin are compromised
Solution Approach 1:
The patent employs a composite light-shielding layer structure combining silicon oxide with other materials to achieve both thin thickness for high resolution and sufficient chemical resistance. The multi-material composition allows optimization of both optical properties and chemical durability simultaneously.
Solution Approach 2:
The patent optimizes the thickness parameter of the light-shielding layer to a specific range (5-50 nm for silicon oxide portion) and controls compositional parameters to achieve the desired balance between resolution and chemical resistance. This parameter optimization enables thin films to maintain both high resolution and adequate reliability.
3Manufacturing precision
If the light-shielding layer thickness is reduced to improve resolution, then the pattern resolution is improved, but the defect repair margin is insufficient
Solution Approach 1:
The patent uses a composite light-shielding layer structure where the silicon oxide layer works in conjunction with other materials to provide both thinness for resolution and sufficient defect repair margin. The multi-layer composite configuration allows each material to contribute different properties, enabling thin films with adequate repair capability.
Data Source
AI summary
Provided is a blankmask with a light-shielding layer including a light block layer and an anti-reflective layer, and a hard mask film. The light block layer and the anti-reflective layer are formed by combining a layer formed of a MoSi compound and a layer formed of a MoTaSi compound. Thus, the blankmask enables formation of a pattern of 32 nm or less, since the light-shielding layer can be thinly formed to a thickness of 200 to 700 and a photomask having pattern fidelity corresponding to the resolution of the pattern can be formed. The light-shielding layer has an optical density of 2.0 to 4.0 at an exposure wavelength of 193 nm, chemical resistance, and a sufficient process margin for defect repair. Further, the hard mask film is formed to a thickness of 20 to 50 using a compound including tin (Sn) and chromium (Cr), thereby decreasing an etch rate of the hard mask film. Accordingly, a resist film can be formed as a thin film, thereby manufacturing a high-resolution blankmask.