Fe-Ni Metal Mask Surface Control for Uniform Etching and Low Warpage
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Solution Overview
Problem
Current metal mask materials for organic EL displays face challenges in achieving high-definition pattern formation with minimal side etching and improved adhesion to resist, despite advancements in etching processability.
Innovation Solution
A metal mask material composed of an Fe-Ni alloy with specific chemical composition and surface roughness characteristics, including C: 0.01% or less, Si: 0.5% or less, Mn: 1.0% or less, and Ni: 30 to 50%, with controlled surface roughness and skewness, and a production method involving cold rolling with optimized rolling reduction ratio and bite angle, to enhance adhesion and minimize shape change during etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If surface roughness is reduced to improve etching uniformity, then etching processability is improved, but adhesion to resist deteriorates
Solution Approach 1:
The patent applies local quality by creating different surface roughness characteristics in different directions. The surface roughness in the rolling direction is controlled at Ra 0.03-0.15 μm for good adhesion, while the surface roughness perpendicular to the rolling direction is controlled at Ra 0.08-0.20 μm for uniform etching. This directional differentiation allows the same surface to simultaneously satisfy both adhesion requirements and etching uniformity requirements.
2Manufacturing precision
If etching pattern definition is improved, then manufacturing precision is improved, but side etching increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling multiple surface parameters simultaneously: surface roughness in rolling direction (Ra 0.03-0.15 μm), surface roughness perpendicular to rolling direction (Ra 0.08-0.20 μm), and skewness (Rsk ≥ 0). By optimizing these parameters together rather than individually, the patent achieves high pattern definition while suppressing side etching through the combined effect of appropriate surface characteristics.
3Reliability
If surface roughness is increased to improve adhesion to resist, then reliability is improved, but etching uniformity deteriorates
Solution Approach 1:
The patent applies asymmetry by intentionally creating asymmetric surface roughness characteristics where the surface roughness perpendicular to the rolling direction (Ra 0.08-0.20 μm) is deliberately made larger than the surface roughness in the rolling direction (Ra 0.03-0.15 μm). This asymmetric configuration allows the surface to provide sufficient adhesion through the perpendicular roughness while maintaining etching uniformity through the controlled rolling direction roughness.
Data Source
AI summary
Provided are: a metal mask material the shape change of which after etching is suppressed and which is preferable in order to achieve good resist adhesiveness and good etching workability; and a production method for the metal mask material. The metal mask material has a surface roughness in the rolling direction and a surface roughness in a direction perpendicular to the rolling direction, which satisfy 0.05 µm≤Ra≤0.25 µm and Rz≤1.5 µm. The metal mask material has a skewness Rsk of 0 or greater in the direction perpendicular to the rolling direction. When a sample having a length of 150 mm and a width of 30 mm is cut out of the metal mask material and the thickness of the sample is reduced by 60% by etching from one side of the sample, the amount of warpage of the sample is 15 mm or less. The metal mask material has a thickness of 0.10-0.5 mm.