Mask Assembly Thickness Variation for Deposition Uniformity
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Solution Overview
Problem
The existing mask assembly technologies face defects due to repulsive forces generated between the mask assembly and the process target during the manufacturing of display devices, particularly due to differences in effective thickness and volume between different mask areas, which affect the uniformity of the magnetic force and quality of the deposition process.
Innovation Solution
A mask assembly design is introduced, featuring a first mask area with first opening areas and a second mask area with second opening areas, half-etching areas, and a non-etching area, where the centers of the second opening areas are located at the vertices of virtual squares, and the non-etching area surrounds these areas. This design minimizes the difference in effective thickness between the first and second mask areas to prevent repulsive forces by optimizing the arrangement of opening areas, half-etching areas, and non-etching areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the mask assembly has uniform thickness across all areas, then manufacturing is simpler, but repulsive forces cause defects during deposition
Solution Approach 1:
The mask assembly employs different thicknesses in different areas: the first mask area has a first effective thickness while the second mask area has a second effective thickness that is greater than or equal to the first effective thickness. This local variation in thickness compensates for the repulsive forces generated during deposition, ensuring uniform deposition quality across different display areas without requiring complete redesign of the entire mask structure.
2Reliability
If the second mask area has greater effective thickness, then repulsive forces are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies that the difference between the first effective thickness and the second effective thickness is controlled to be about 3 μm or less. This quantitative parameter control ensures that the thickness variation is sufficient to compensate for repulsive forces while maintaining manufacturability and avoiding excessive precision requirements that would make production impractical.
3Area of stationary object
If the mask assembly covers larger area for increased display area, then device functionality improves, but repulsive forces increase causing defects
Solution Approach 1:
The mask assembly is divided into a first mask area corresponding to a first display area and a second mask area corresponding to a second display area. The second mask area has greater effective thickness to compensate for repulsive forces, allowing the overall mask to cover larger areas with multiple functions while maintaining deposition quality across different regions.
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 optimized mask assembly effectively reduces the repulsive force between the mask assembly and the process target, ensuring better adherence and quality of the deposition process, thereby preventing defects and improving the manufacturing process for display devices.
Implementation Method 1
differences in effective thickness and volume between different mask areas, which affect the uniformity of the magnetic force
Data Source
AI summary
A mask assembly includes a first mask area including first opening areas, and a second mask area including second opening areas having centers located at vertices of virtual squares in a row direction and a column direction, half-etching areas having centers located at centers of the virtual squares, and a non-etching area surrounding the second opening areas and the half-etching areas. Each of the second opening areas includes a base portion and at least one protrusion portion protruding from the base portion.