Mask Frame Assembly Wrinkle Reduction via Offset Half-Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-resolution mask frames for thin film deposition in organic light-emitting display devices are prone to wrinkling due to structural instability, which affects the precision and uniformity of the thin film pattern formed, making it difficult to achieve high light-emission efficiency.
Innovation Solution
A mask frame assembly with unit masks that undergo half etching from different surfaces to create offset thickness regions, reducing non-uniformity and minimizing wrinkles, ensuring precise contact with the substrate for accurate thin film deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the mask is made thin to reduce shadows and improve pattern precision, then the shadow reduction is achieved, but wrinkles are generated due to structural instability
Solution Approach 1:
The mask is designed with non-uniform thickness distribution, where the central region has a greater thickness than the edge regions. This local variation in thickness provides structural support where needed while maintaining the overall thin profile, preventing wrinkles without compromising pattern precision.
Solution Approach 2:
The thickness parameter of the mask is changed from a uniform value to a gradient distribution, with the central thickness being greater than the edge thickness. This parameter modification addresses the structural instability issue while preserving the shadow-reduction benefit of a thin mask.
2Area of stationary object
If the mask is extended in one axis to cover larger area, then the coverage area is increased, but wrinkles are generated due to tensile force
Solution Approach 1:
The mask incorporates regions of varying thickness to provide localized structural support. The thicker central region counteracts the tensile forces generated during extension, allowing the mask to cover a larger area without developing wrinkles.
3Object-affected harmful factors
If the mask thickness is reduced to minimize shadow effects, then shadow reduction is achieved, but non-uniform thickness causes deposition non-uniformity
Solution Approach 1:
The mask features a carefully designed thickness profile where the central region is thicker and the edge regions are thinner. This local quality variation compensates for the shadow effects while maintaining uniform deposition across the substrate by providing appropriate support in different regions.
Data Source
AI summary
A mask frame assembly for thin film deposition includes a frame having an opening and at least two unit masks having end parts in a longitudinal direction fixed to the frame, each of the unit masks comprising first regions and second regions, the first regions having unit masking patterns, each of the unit masking patterns having a plurality of openings for thin film deposition, the unit masking pattern being spaced apart from each other, each of the second regions being interposed between a pair of adjacent ones of the first regions, the first regions having a first thickness from a first surface of the unit masks, and at least a portion of the second regions having a second thickness from a second surface of the unit masks opposite to the first surface of the unit masks, such that the first regions and the at least the portion of the second regions are offset from each other in a direction normal to the first and second surfaces. A plurality of unit masks are each half etched from different surfaces and thus a height of wrinkles generated in the mask of the mask frame assembly may be reduced.