OLED Metal Mask Material Composition for Low-Warpage Etching
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Solution Overview
Problem
The existing metal masks for OLED manufacturing suffer from warpage issues during the etching process, leading to precision alignment problems and positional deviations in pixel patterns, which affect the formation of organic compound layers, due to residual stress and microstructure-related challenges.
Innovation Solution
A metal mask material with a specific composition of Ni, Co, and Fe, along with controlled impurities, is developed, with a thickness of 5.00 μm to 50.00 μm, where the warpage is minimized by adjusting the {111} lattice spacing, FWHM, and diffraction intensities, and the manufacturing process involves hot rolling, cold rolling, and tension annealing to achieve reduced residual stress and improved etching precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an Invar alloy is used for the metal mask material, then dimensional stability during manufacturing is improved, but warpage occurs during etching due to residual stress
Solution Approach 1:
The invention changes the material parameters by specifying a precise composition range (Ni: 35.0-37.0%, Co: 0.00-0.50%, Fe: balance) and controlling impurity levels to optimize the alloy's properties. This compositional parameter optimization reduces residual stress while maintaining dimensional stability, preventing warpage during etching and ensuring alignment precision.
Solution Approach 2:
The invention creates an optimized composite alloy system combining Fe, Ni, and Co in specific proportions. This composite material approach leverages the complementary properties of each element: Fe provides structural stability, Ni reduces thermal expansion and residual stress, and Co enhances etching uniformity. The synergistic combination resolves the contradiction between dimensional stability and warpage prevention.
2Manufacturing precision
If the metal mask thickness is increased to prevent shadowing effect, then deposition uniformity is improved, but warpage after etching increases
Solution Approach 1:
The invention optimizes the thickness parameter within a specific range (5.00-50.00 μm) and combines it with compositional parameters (Ni: 35.0-37.0%, Co: 0.00-0.50%) to achieve the best balance. This multi-parameter optimization ensures sufficient thickness to prevent shadowing while the optimized composition minimizes residual stress, thereby reducing warpage after etching.
3Stress or pressure
If annealing process is used to remove internal stress, then residual stress is reduced, but dimensional changes occur in the metal sheet
Solution Approach 1:
The invention changes the material parameters by optimizing the alloy composition (Ni: 35.0-37.0%, Co: 0.00-0.50%, Fe: balance) to inherently reduce residual stress. This compositional optimization minimizes the need for aggressive annealing processes that cause dimensional changes, allowing stress relief with minimal impact on the metal sheet dimensions.
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 results in a metal mask with significantly reduced warpage, enabling high precision etching suitable for higher pixel densities in OLED manufacturing, ensuring accurate pattern formation and improved manufacturing efficiency.
Implementation Method 1
a process of hot rolling and coiling the slab to obtain hot rolled coil, a process of alternately cold rolling and annealing the hot rolled coil
Implementation Method 2
a tension annealing process, the tension annealing process being performed after the final rolling process, a rolling reduction in a final rolling process being 30.0% or more and 95.0% or less, and the tension annealing process being performed by an annealing temperature of 300 to 900° C. in a reducing atmosphere
Implementation Method 3
obtained by grazing incidence X-ray diffraction technique
Data Source
AI summary
A metal mask material for OLED use reduced in amount warpage due to etching, a method for manufacturing the same, and a metal mask are provided. The metal mask material and metal mask of the present invention contain, by mass %, Ni: 35.0 to 37.0% and Co: 0.00 to 0.50%, have a balance of Fe and impurities, have thicknesses of 5.00 μm or more and 50.00 μm or less, and have amounts of warpage defined as maximum values in amounts of rise of four corners of a square shaped sample of the metal mask material of 100 mm sides when etching the sample from one surface until the thickness of the sample becomes ⅖ and placing the etched sample on a surface plate of 5.0 mm or less.