OLED Electrode Step Structure for Mask Reduction
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Solution Overview
Problem
The high manufacturing cost of OLED display devices due to the use of multiple masks in the photolithograph process for forming electrodes, thin film transistors, and organic emission layers increases with the number of masks required.
Innovation Solution
The OLED display device incorporates a substrate with a semiconductor, gate electrode, source electrode, drain electrode, and pixel electrode, each comprising a barrier metal layer, low resistance metal layer, and metal oxide layer, formed using a method that includes sequential deposition and patterning of these layers to create a step-shaped structure, reducing the need for multiple masks and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple masks are used in the photolithograph process to form electrodes, thin film transistors, and organic emission layers, then the manufacturing precision and pattern formation capability are improved, but the manufacturing cost increases significantly
Solution Approach 1:
The patent combines multiple photolithography processes into a single wet etching process. The multi-layer electrode structure (barrier metal layer, low resistance metal layer, and metal oxide layer) is patterned simultaneously using one mask and one wet etching step, eliminating the need for multiple separate photolithography processes that would require multiple masks. This merging of processes maintains pattern formation capability while significantly reducing manufacturing cost and complexity.
Solution Approach 2:
The single wet etching process serves multiple functions: it patterns all electrode layers (barrier metal, low resistance metal, and metal oxide), forms contact holes, and creates the step-shaped electrode structure. This multi-functional approach replaces multiple specialized photolithography steps, reducing the total number of masks and processes required while maintaining manufacturing precision.
2Device complexity
If the number of masks increases in the photolithograph process, then more complex patterns and structures can be formed, but the manufacturing cost increases proportionally
Solution Approach 1:
The patent merges the patterning of multiple electrode layers into a single wet etching process. The barrier metal layer, low resistance metal layer, and metal oxide layer are all patterned simultaneously using one mask, eliminating the need for separate photolithography steps for each layer. This approach maintains the complexity of the multi-layer electrode structure while reducing the number of masks required.
Solution Approach 2:
The patent introduces a vertical dimension to the electrode structure by creating a step-shaped profile with different layer widths. The barrier metal layer has a first width, the low resistance metal layer has a second width, and the metal oxide layer has a third width, forming a stepped configuration. This dimensional approach allows complex three-dimensional electrode structures to be formed through a single patterning process rather than requiring multiple masks.
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 reduces manufacturing costs by simplifying the process and eliminating the need for additional masks, while maintaining the performance of OLED display devices by ensuring proper electrical connections and light emission.
Implementation Method 1
a barrier metal material layer, a low resistance metal material layer, a contact assistant material layer, and a metal oxide material layer are sequentially deposited on the interlayer insulating layer
Data Source
AI summary
An organic light emitting diode display includes a substrate, a semiconductor, a gate electrode, a source electrode connected to a first portion of the semiconductor, a drain electrode connected to a second portion of the semiconductor, and a pixel electrode connected to the drain electrode. Each of the source electrode, the drain electrode, and the pixel electrode includes a barrier metal layer, a low resistance metal layer, a metal oxide layer, and a contact assistant layer disposed between the low resistance metal layer and the metal oxide layer. The source electrode, the drain electrode, and the pixel electrode each have a step shape.