Organic EL Patterning via Sacrificial Layer Solvation
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Solution Overview
Problem
The existing methods for manufacturing organic electroluminescence (EL) display devices using photolithography result in inferior element characteristics due to residual polymer materials from resist, intermediate, and peeling layers, which are difficult to completely remove, leading to degradation of organic EL elements.
Innovation Solution
A method involving the formation of a sacrificial layer soluble in a polar solvent, followed by an intermediate layer of water-soluble polymer, and multiple contact steps with a polar solvent to selectively remove the sacrificial layer, ensuring the organic compound layer is protected and maintaining element characteristics comparable to those formed with a metal mask in a vacuum in-situ process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography process is used to produce fine organic EL elements, then manufacturing precision and productivity are improved, but element characteristics deteriorate due to residual polymer materials
Solution Approach 1:
The patent segments the removal process into multiple sequential steps: first removing the photoresist layer, then removing the intermediate layer, and finally removing the peeling layer. Each layer is removed by a specifically designed solvent treatment, ensuring complete removal without residue that would harm element characteristics.
Solution Approach 2:
The patent introduces an intermediate layer made of water-soluble polymer between the photoresist and the organic compound layer. This intermediate layer serves as a mediator that facilitates the complete removal of photoresist residues by water-based solvents, preventing contamination of the organic EL elements while enabling effective photolithography processing.
2Ease of manufacture
If polymer material is used for resist, intermediate layer, or peeling layer, then ease of manufacture is improved, but removal difficulty increases due to adsorption to film surface
Solution Approach 1:
The patent changes the chemical parameters of the polymer materials used in each layer. The intermediate layer uses water-soluble polymer, the peeling layer uses polymer soluble in specific organic solvents, and the photoresist uses polymer soluble in alkaline solutions. These parameter changes ensure each layer can be completely removed by its corresponding solvent without leaving residues on the film surface.
Solution Approach 2:
The patent assigns different local qualities (solubility characteristics) to each layer: the intermediate layer is water-soluble, the peeling layer is soluble in organic solvents like chlorobenzene or ethyl acetate, and the photoresist is soluble in alkaline developers. This local differentiation enables selective and complete removal of each layer without affecting the organic compound layer.
3Manufacturing precision
If multiple layers (resist, intermediate, peeling) are used in photolithography, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent employs periodic sequential removal actions: first applying and removing photoresist, then applying and removing intermediate layer, then applying and removing peeling layer. Each removal step uses a different solvent system, creating a periodic pattern of deposition and removal that systematically eliminates all polymer residues while maintaining patterning precision.
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 approach effectively removes residual layers, enhancing the element characteristics of organic EL elements and achieving performance comparable to those produced with vacuum in-situ methods, while allowing for high-definition pixel sizes and large substrate support.
Implementation Method 1
a sacrificial layer-forming step of forming a sacrificial layer soluble in a polar solvent on the organic compound layer
Implementation Method 2
an intermediate layer-forming step of forming an intermediate layer formed of a water-soluble polymer on the sacrificial layer
Data Source
AI summary
The method of manufacturing an organic electroluminescence display device includes the steps of: forming an organic compound layer on a first electrode; forming a sacrificial layer soluble in a polar solvent on the organic compound layer; forming an intermediate layer formed of a water-soluble polymer on the sacrificial layer; patterning the sacrificial layer, the intermediate layer, and the organic compound layer; removing the intermediate layer and a layer formed thereon; and removing the sacrificial layer, in which the step of removing the sacrificial layer includes a step of performing a contacting step of bringing the sacrificial layer and the polar solvent into contact with each other a plurality of times.