Organic Thin Film Transistor Array Substrate Single Photo Mask Patterning
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Solution Overview
Problem
The high manufacturing cost of organic thin film transistor substrates due to the numerous photo mask processes required, which also leads to oxidation of low work function metals like silver, reducing their conduction ability.
Innovation Solution
A method of manufacturing organic thin film transistor array substrates using a first half transparent photo mask to pattern data lines, scan lines, sources, and drains in a single process, reducing the number of photo mask steps and applying a transparent electrode layer to prevent oxidation of the metal layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple photo mask processes are used to pattern data lines, sources, drains and pixel electrodes, then manufacturing precision is improved, but manufacturing cost increases and productivity decreases
Solution Approach 1:
The patent combines multiple patterning operations into a single photo mask process by using a half-transparent photo mask that allows simultaneous formation of data lines, sources, drains and pixel electrodes. This merging of operations reduces the total number of photo mask steps from 6-7 to just one, thereby improving productivity while maintaining manufacturing precision through the half-transparent mask's ability to create different thickness regions in a single exposure.
Solution Approach 2:
The patent introduces a new dimension to the photo mask process by using a half-transparent mask that creates varying light transmission levels. This allows the formation of different pattern densities and metal layer thicknesses simultaneously in one process step, effectively adding a dimensional control mechanism that enables complex patterning without requiring multiple sequential steps.
2Reliability
If low work function metal silver is used to decrease contact resistance, then electrical conduction is improved, but oxidation resistance deteriorates
Solution Approach 1:
The patent creates a composite electrode structure by depositing a transparent electrode layer (such as ITO) over the metal silver layer. This composite structure combines the low work function and high conduction ability of silver with the oxidation resistance and transparency of the transparent electrode material, thereby achieving both improved electrical conduction and protection against oxidation simultaneously.
Solution Approach 2:
The transparent electrode layer acts as an intermediary protective barrier between the reactive metal silver and the oxidizing environment. This intermediate layer prevents direct contact between oxygen and the silver, thereby protecting the silver from oxidation while maintaining electrical conduction through the transparent electrode material.
3Ease of manufacture
If metal silver is exposed without covering protect layer, then ease of manufacture is improved, but reliability deteriorates due to oxidation
Solution Approach 1:
The patent applies preliminary protective action by depositing the transparent electrode layer over the metal silver layer before subsequent processing steps. This preliminary protection ensures that the silver is already shielded from oxidation during manufacturing processes, maintaining both ease of manufacture and long-term reliability without requiring additional protective steps later.
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 decreases manufacturing costs and maintains the conduction properties of the metal layers by reducing photo mask process steps and covering the metal layers with a transparent electrode layer, thereby preventing oxidation.
Implementation Method 1
transparent electrode layer covered on the first metal layer which could avoid oxidation of the first metal layer
Implementation Method 2
using a first half transparent photo mask for patterning treatment
Data Source
AI summary
An organic thin film transistor array substrate and manufacture method thereof, display device are provided. The method of manufacturing organic thin film transistor array substrate, comprising: providing substrate; depositing first metal layer, transparent electrode layer and photoresist layer on substrate by sequentially; using first half transparent photo mask for patterning treatment, and forming data line, source, drain and pixel electrode, wherein channel region is forming between source and drain; depositing semiconducting layer, insulating layer and second metal layer by sequentially; using second photo mask for patterning treatment, and forming active layer, grid insulating layer, grid on channel region, grid is connecting to scan line; depositing passivation layer; using third photo mask for patterning treatment and exposing pixel electrode; forming OLED material on pixel electrode. According to the method above could effectively reduce photo mask process and reduce cost.