Moth-Eye Mold Aluminum Alloy Grain Control
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Solution Overview
Problem
Aluminum films formed on organic insulating layers often contain abnormal grains due to abnormal crystal growth, leading to haze in antireflection films and difficulties in controlling grain formation density, which affects mass productivity and the ability to produce films without antiglare functionality.
Innovation Solution
A mold manufacturing method involving a mold base with a metal base, an organic insulating layer, and an aluminum alloy layer containing a non-aluminum metal element with a standard electrode potential difference not exceeding 0.64 V, where the aluminum alloy layer is partially anodized and then etched to form a porous alumina layer with controlled recessed portions, reducing abnormal grain formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an aluminum film is formed on an organic insulating layer, then the mold can be manufactured with simple structure, but abnormal grains are generated due to abnormal crystal growth causing haze in antireflection films
Solution Approach 1:
The invention changes the material parameters by using an aluminum alloy layer instead of pure aluminum film. The alloying elements (such as Si, Mg, Mn, Zn, or Cu at 0.01-5 mass%) modify the crystal growth characteristics, suppressing abnormal grain formation while maintaining the anodization processability and mold manufacturing simplicity.
Solution Approach 2:
The invention employs a composite material approach by creating an aluminum alloy layer with specific compositional ranges. This composite structure combines aluminum with controlled amounts of other elements to achieve both the desired grain structure (preventing haze) and the chemical reactivity needed for porous alumina formation through anodization.
2Reliability
If the aluminum film is partially anodized to form porous alumina layer, then antireflection function is achieved, but the process becomes complex with multiple steps
Solution Approach 1:
The invention applies preliminary action by forming the porous alumina layer through controlled partial anodization before final mold completion. This preliminary porous structure creation enables subsequent etching and finishing steps to proceed more effectively, achieving the antireflection function while streamlining the overall process through proper sequencing.
3Manufacturing precision
If the porous alumina layer is etched to enlarge recessed portions, then the antireflection performance is improved, but the manufacturing time increases
Solution Approach 1:
The invention optimizes the etching process parameters including solution composition (HF, HNO3, CH3COOH in specific ratios), temperature (20-40°C), and etching time (1-30 minutes) to achieve the desired recessed portion enlargement (0.5-5 μm) while minimizing processing time. The controlled parameters balance precision and productivity.
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
This method significantly reduces the probability of abnormal grain production in aluminum films, enabling the creation of haze-free antireflection films with improved productivity and controlled grain density.
Implementation Method 1
anodizing of aluminum has been receiving attention... An aluminum base is immersed in an acidic electrolytic solution of sulfuric acid, oxalic acid, phosphoric acid, or the like, or an alkaline electrolytic solution, and this is used as an anode in application of a voltage, which causes oxidation and dissolution
Implementation Method 2
application of a voltage, which causes oxidation and dissolution. The oxidation and the dissolution concurrently advance over a surface of the aluminum base to form an oxide film
Implementation Method 3
bringing the porous alumina layer into contact with an etching solution, thereby enlarging the plurality of minute recessed portions
Data Source
AI summary
A method for manufacturing a moth-eye mold of an embodiment of the present invention employs a mold base including a metal base, an organic insulating layer provided on the metal base, and an aluminum alloy layer provided on the organic insulating layer, the aluminum alloy layer containing aluminum and a non-aluminum metal element M, an absolute value of a difference between a standard electrode potential of the metal element M and a standard electrode potential of aluminum being not more than 0.64 V, and a content of the metal element M in the aluminum alloy layer not exceeding 10 mass %.