OLED Lift-Off Deposition for High-Resolution Pixel Alignment
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Solution Overview
Problem
The limitation of using a fine metal mask (FMM) in manufacturing high-resolution organic light-emitting display apparatus due to shadow effects necessitates an alternative deposition technology to reduce defects.
Innovation Solution
A method involving the formation of pixel electrodes and a pixel-defining layer, followed by a lift-off process with a fluoropolymer layer and photoresist, and subsequent deposition of intermediate and passivation layers using physical vapor deposition (PVD), chemical vapor deposition (CVD), or atomic layer deposition (ALD) to achieve improved step coverage and reduce misalignment issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fine metal mask (FMM) is used for depositing organic emission layer, then deposition precision is improved, but shadow effects occur causing manufacturing defects
Solution Approach 1:
The patent removes the fine metal mask from the deposition process entirely, replacing it with a lift-off layer and photoresist system. This extraction eliminates the shadow effects caused by the mask while maintaining the ability to achieve precise pattern deposition through the alternative lift-off mechanism.
Solution Approach 2:
The patent introduces a lift-off layer as an intermediary between the substrate and the organic emission layer. This intermediate layer, combined with photoresist patterning, serves as a mediator that enables precise deposition without the shadow effects of a fine metal mask, allowing the organic material to be deposited conformally and then selectively removed.
2Ease of manufacture
If conventional deposition methods are used, then process simplicity is maintained, but misalignment and defects increase
Solution Approach 1:
The patent performs preliminary patterning of the lift-off layer and photoresist before the actual organic emission layer deposition. This preliminary action establishes precise alignment guides that ensure accurate positioning of subsequent layers, preventing misalignment defects while maintaining a relatively simple overall process flow.
Solution Approach 2:
The patent replaces the mechanical fine metal mask system with a chemical/photochemical patterning system using lift-off layers and photoresist. This substitution eliminates the mechanical shadow effects and alignment issues of FMM while achieving comparable or superior precision through chemical etching and photo patterning processes.
3Loss of time
If passivation layer coverage is incomplete, then deposition time is reduced, but opposite electrode protection is compromised
Solution Approach 1:
The patent ensures complete passivation layer coverage by utilizing the vertical dimension and conformal deposition characteristics. The passivation layer is deposited to cover not only the horizontal surfaces but also the vertical sidewalls of the opposite electrode, creating a three-dimensional protective barrier that ensures complete coverage without requiring extended deposition times.
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 reduces manufacturing defects by preventing misalignment and ensuring complete coverage of the opposite electrodes, thereby enhancing the production of high-resolution organic light-emitting displays.
Implementation Method 1
the opening may be defined by etching the lift-off layer using a first solvent including fluorine
Implementation Method 2
the first deposition process may use a physical vapor deposition process
Implementation Method 3
the third deposition process may use a chemical vapor deposition process or an atomic layer deposition process
Implementation Method 4
after the third deposition process, dry etching may be performed inside a same chamber as a chamber in which the third deposition process is performed
Data Source
AI summary
A method of manufacturing an organic light-emitting display apparatus includes forming a pixel electrode and a pixel-defining layer on a substrate, the pixel-defining layer covering edges of the pixel electrode sequentially forming a lift-off layer and a photoresist on the pixel electrode and the pixel-defining layer patterning the lift-off layer and the photoresist to define an opening that exposes a top surface of the pixel electrode and a portion of the pixel-defining layer sequentially forming an intermediate layer and an opposite electrode in the opening and on the photoresist, the intermediate layer including an emission layer forming a passivation layer to cover an entirety of a top surface and end portions of the opposite electrode and removing the lift-off layer and the photoresist that remain outside the opening.