Oxide TFT Array Substrate with Oxidized Etch-Stop Channel Protection
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Solution Overview
Problem
Oxide thin-film transistors with a back channel etch (BCE) structure face stability issues due to exposure to etchant liquids and dry etching processes, leading to potential damage of the oxide channel, and conventional solutions increase production steps and costs by adding additional film layers and masks.
Innovation Solution
An array substrate design that includes a base, primary gate electrode, active layer, etch stop layer, source and drain electrodes, and a passivation layer, where the etch stop layer is oxidized to protect the active layer, and the source and drain electrodes are connected through a metal connection layer to prevent damage during etching, with specific materials like Ti for the etch stop layer and Mo, MoTi, or MoNi for the connection layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a BCE structured oxide thin-film transistor is used, then high mobility is achieved, but the oxide channel is exposed and easily damaged by etchant liquid, leading to poor stability
Solution Approach 1:
The patent introduces an etch stop layer as an intermediary protective structure between the oxide channel and the etchant liquid. This etch stop layer is selectively etched away after serving its protective function, allowing the source and drain electrodes to contact the oxide channel. The etch stop layer acts as a temporary mediator that prevents etchant damage during manufacturing while enabling subsequent electrical connectivity.
2Object-affected harmful factors
If an SiOx insulation film layer is added as an etch stop structure, then the oxide channel is protected from damage, but operation steps and cost increase
Solution Approach 1:
The patent combines the etch stop layer function with the source and drain electrode formation process. The etch stop layer is formed as part of the same metal layer structure that will become the source and drain electrodes, eliminating the need for a separate SiOx insulation film layer. This merging of functions reduces the number of process steps while maintaining protection during manufacturing.
Solution Approach 2:
The patent changes the material parameter of the etch stop layer from traditional SiOx insulation material to a metal layer material that can be selectively etched. This parameter change allows the same layer to serve both as a protective etch stop structure and as the conductive source/drain electrode material, reducing process complexity.
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
The proposed solution effectively protects the active layer from etchant damage, maintaining device stability by forming a metal film layer that oxidizes to form an oxide layer, preventing incorrect etching and ensuring functional integrity throughout the manufacturing process.
Implementation Method 1
an area of the etch stop layer is not covered by the source electrode and the drain electrode and is arranged as an oxidized metal layer
Data Source
AI summary
An array substrate and a manufacturing method thereof are provided. A metal film layer is formed on an active layer of the array substrate. The metal film layer protects the active layer from being damaged by an etchant liquid or dry etching process during patterning processing of a source electrode/a drain electrode. Afterwards, a portion of the metal film layer that corresponds to a channel of the active layer the channel is subjected to oxidizing processing to form an oxide layer to help keep the functional property of the active layer. In the entire manufacturing process of the array substrate, the active layer will not be subject to damage in subsequent processing and stability of the device can be maintained.