OLED Metal Wire Short Circuit Prevention via Mask Shadowing Control
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Solution Overview
Problem
In organic light emitting diode (OLED) display device manufacturing, a short circuit occurs between metal wires due to the incomplete removal of the indium tin oxide layer, caused by the shadowing effect of the organic layer during the exposure step.
Innovation Solution
A method involving the formation of an inorganic layer, metal wires, an organic layer, and an indium tin oxide layer, followed by coating a photoresist layer and using a photo mask with an opaque material of specific dimensions to control the exposure and etching process, ensuring complete removal of the indium tin oxide layer and organic layer between the metal wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional photo mask without opaque material is used during exposure, then the manufacturing process is simple, but the organic layer creates shadowing effect causing incomplete removal of indium tin oxide layer and short circuit between metal wires
Solution Approach 1:
An opaque material layer is introduced as an intermediary element on the photo mask, positioned between the light source and the substrate. This intermediary selectively blocks light in specific regions to prevent shadowing effects caused by the organic layer thickness, ensuring complete removal of the indium tin oxide layer in critical areas while maintaining electrical insulation between metal wires.
Solution Approach 2:
The opaque material is pre-positioned on the photo mask before the exposure process begins. This preliminary configuration ensures that light is blocked in the correct regions from the start of exposure, preventing the shadowing effect that would otherwise cause incomplete etching and potential short circuits between adjacent metal wires.
2Manufacturing precision
If the organic layer is made thick to provide sufficient coverage, then the coverage and protection are improved, but the shadowing effect during exposure worsens causing etching problems
Solution Approach 1:
The opaque material on the photo mask acts as an intermediary that compensates for the shadowing effect created by the thick organic layer. By strategically placing opaque material in regions where shadowing would prevent proper etching, the system ensures complete removal of the indium tin oxide layer despite the organic layer's thickness providing necessary coverage.
3Productivity
If the photo mask has full transparency for light passage, then the exposure efficiency is high, but the indium tin oxide layer cannot be completely removed in shadowed regions leading to short circuits
Solution Approach 1:
The photo mask is designed with non-uniform optical properties through the selective placement of opaque material in specific regions. This local modification allows most areas to maintain high light transmission for efficient exposure, while critical regions between metal wires have enhanced light blocking to prevent shadowing effects and ensure complete etching, thus maintaining both productivity and reliability.
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 prevents short circuits by ensuring the indium tin oxide layer is removed completely, maintaining the integrity of the metal wires and enhancing the manufacturing process of OLED displays.
Implementation Method 1
the organic layer 106 generates shadowing effect
Implementation Method 2
performing an exposure step to the photoresist layer by utilizing a photo mask
Implementation Method 3
performing an etching step to remove a part of the indium tin oxide layer and a part of the organic layer
Data Source
AI summary
Disclosed is a method for preventing a short circuit between metal wires in an organic light emitting diode display device. The method includes: forming an inorganic layer on a substrate; forming a metal layer including two metal wires on the inorganic layer; forming an organic layer on the two metal wires; forming an indium tin oxide layer on the organic layer; coating a photoresist layer; performing an exposure step by utilizing a photo mask having a transparent area, an opaque material disposed in the transparent area, wherein a width of the opaque material is less than a width of the transparent area; performing a development step to the photoresist layer; and performing an etching step to remove a part of the indium tin oxide layer and a part of the organic layer. The present invention can prevent the short circuit between the metal wires.