Vapor Deposition Metal Mask Step Height Uniformity
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Solution Overview
Problem
Vapor deposition metal masks exhibit non-uniform film thickness due to varying deposition material distribution across mask holes, caused by differences in the direction and intensity of vapor deposition sources, leading to inconsistent pattern formation.
Innovation Solution
A vapor deposition metal mask design with a central region and end regions, where the connection portions between large and small holes in the end regions have a smaller step height than in the central region, limiting material passage and improving uniformity, regardless of the number of vapor deposition sources used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a vapor deposition source is positioned to maximize material discharge at the center of the mask region, then the film thickness in central mask holes is improved, but the film thickness uniformity across end region mask holes deteriorates
Solution Approach 1:
The connection portions are designed with different step heights depending on their location within the mask region. End region connection portions have smaller step heights than central region connection portions, creating location-dependent structural properties to compensate for non-uniform vapor deposition material distribution and achieve uniform film thickness across all mask holes.
Solution Approach 2:
The step height parameter of the connection portions is varied based on their position in the mask region. By changing this geometric parameter spatially, the patent compensates for the varying vapor deposition material intensity across different mask hole locations, thereby achieving uniform film thickness despite the complex vapor source configuration.
2Manufacturing precision
If the step height of connection portions is increased to improve mask hole sealing, then the vapor deposition material passage is reduced, but the film thickness uniformity deteriorates
Solution Approach 1:
Different regions of the mask have different connection portion step heights tailored to their specific vapor deposition requirements. End region mask holes with smaller step heights receive less material blocking, while central region mask holes with larger step heights receive more material blocking, achieving uniform overall film thickness.
Solution Approach 2:
The step height parameter is optimized for each region based on the vapor deposition material distribution characteristics. This localized parameter optimization balances the competing requirements of material passage control and film thickness uniformity, making the manufacturing process more manageable despite the regional variations.
3Area of stationary object
If multiple vapor deposition sources are used to cover the entire mask region, then the deposition coverage is improved, but the film thickness uniformity across different mask holes deteriorates
Solution Approach 1:
The mask holes are strategically positioned and sized with location-dependent connection portion step heights that compensate for the non-uniform material distribution caused by multiple vapor deposition sources. This ensures that even though different regions receive different amounts of vapor deposition material, the final film thickness is uniform across all mask holes.
Solution Approach 2:
The geometric parameters of the mask holes, particularly the connection portion step heights, are varied spatially to counterbalance the effects of multiple vapor deposition sources. By adjusting these parameters based on location, the patent achieves uniform film thickness despite the complexity of coordinating multiple vapor sources for comprehensive coverage.
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 design enhances the uniformity of film thickness across mask holes, improving the consistency of vapor deposition patterns and display quality by controlling the passage of deposition material through optimized step heights and connection portion configurations.
Implementation Method 1
In film formation using the vapor deposition metal mask, vapor deposition material passes through the mask holes from the large openings to the small openings and is deposited on the vapor deposition target
Data Source
AI summary
A vapor deposition metal mask includes a mask region including a plurality of mask holes. A connection portion of each mask hole located at a position other than the center of the mask region has a shape protruding inward of the mask hole along the entire circumference of the mask hole and is configured by a first section, which is a section closer to the center of the mask region and a second section, which is a section closer to one of the ends of the mask region. The distance between the first section and the reverse surface of the mask region is a first step height. The first step height in the end region is smaller than the first step height in the central region.