Tapered Mask Frame for OLED Deposition Shadow Reduction
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Solution Overview
Problem
In PECVD processes for forming passivation layers in OLED displays, existing masks suffer from shadow effects and film-penetration issues due to their right-angled edges and thermal expansion, which affect the uniformity and reliability of thin film deposition.
Innovation Solution
A mask with a frame featuring an inclined inner surface that tapers from the upper end to the lower end, minimizing shadow effects and allowing for precise alignment without separate alignment tools, thereby enhancing the formation of thin film patterns on substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a mask with a right-angled frame edge is used, then the mask structure is simple and easy to manufacture, but shadow effects occur on the substrate affecting deposition uniformity
Solution Approach 1:
The patent applies curvature by replacing the right-angled frame edge with an inclined surface that tapers from the upper end to the lower end. This inclined surface design eliminates the shadow effects caused by vertical edges while maintaining manufacturing feasibility, thereby resolving the contradiction between structural simplicity and deposition uniformity.
2Reliability
If the mask frame is stretched to minimize sagging, then mask stability improves, but film-penetration occurs at the masking region
Solution Approach 1:
The inclined surface design replaces the vulnerable right-angled edge structure that is prone to stretching and film-penetration. The tapered geometry distributes mechanical stress more evenly, maintaining mask stability without causing film-penetration at the masking region.
3Stability of the object's composition
If a mask with thick frame is used, then sagging is minimized, but shadow effects are exacerbated
Solution Approach 1:
The inclined surface design allows the frame to maintain structural stability while eliminating the horizontal shadow-casting edges. The tapered geometry directs deposition material flow smoothly, preventing shadow effects even with a thick frame structure.
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 tapered mask design reduces shadow regions on the substrate, improving the reliability and longevity of OLED displays by ensuring uniform thin film deposition and reducing facility costs through efficient use of substrate space.
Implementation Method 1
The PECVD provides one or more compound gases, which includes an element configuring a thin film material to be formed, onto a substrate and thus forms a desired thin film by a chemical reaction that is performed in a gaseous state or a substrate surface
Implementation Method 2
PECVD induces a reaction with energy due to heat and plasma generated by a Radio Frequency (RF) power
Data Source
AI summary
Disclosed is a mask which can be used for forming a pattern on a substrate in a deposition apparatus, and a method for manufacturing a display device using the same. The mask includes a mask pattern and a frame. The mask has a tapered shape where the inner surface of the frame tapers in a direction from an upper end to a lower end. A thin film pattern is formed on a substrate using the mask pattern of the mask. The frame supports an outer of the mask pattern, and includes an inclined plane which tapers in an inner direction where the mask pattern is disposed.