TFT Substrate Metal Layer Structure for Scanning Antenna Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Scanning antennas with liquid crystal capacitance experience deteriorated antenna characteristics due to metal dissolution from the source metal layer into the liquid crystal layer, leading to a decrease in voltage holding rate and antenna performance.
Innovation Solution
A manufacturing method for a TFT substrate involving specific etching processes and resist layer configurations to form source and drain metal layers with Ti, Ta, or W as lower layers and Cu or Al as upper layers, ensuring the edge of the lower metal layer does not enter inside the edge of the upper metal layer, thereby preventing metal ion dissolution into the liquid crystal layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple single-layer metal structure is used for source and drain electrodes, then manufacturing complexity is reduced, but metal ions dissolve into the liquid crystal layer causing antenna characteristic deterioration
Solution Approach 1:
The patent applies composite material structure by forming a multi-layer metal configuration consisting of a first metal layer (Ti, Ta, or W) and a second metal layer (Cu or Al). This composite structure prevents metal ion dissolution into the liquid crystal layer while maintaining manufacturing feasibility through sequential deposition processes.
2Manufacturing precision
If the lower metal layer edge extends inside the upper metal layer edge, then manufacturing precision is simplified, but metal dissolution occurs leading to voltage holding rate decrease
Solution Approach 1:
The patent implements preliminary action by designing the metal layer structure in advance such that the first metal layer (Ti, Ta, or W) extends beyond the second metal layer (Cu or Al) at the edges. This preliminary configuration ensures complete coverage of the lower metal layer by the interlayer insulating layer, preventing metal ion dissolution before it can affect the liquid crystal layer and maintain voltage holding rate.
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 method effectively suppresses metal ion dissolution and maintains antenna characteristics by ensuring the source metal layer is completely covered by the interlayer insulating layer, thus maintaining the voltage holding rate and antenna performance.
Implementation Method 1
each of a source electrode and the drain electrode including a lower source metal layer including at least one element selected from the group consisting of Ti, Ta, and W, and an upper source metal layer formed on the lower source metal layer and including Cu or Al
Implementation Method 2
forming the upper source metal layer by etching the upper conductive film with the first resist layer as an etching mask
Implementation Method 3
forming a source contact portion connecting the semiconductor layer and the source electrode, and a drain contact portion connecting the semiconductor layer and the drain electrode by etching the contact layer by dry etching with the second resist layer as an etching mask
Data Source
AI summary
A manufacturing method of a TFT substrate is a manufacturing method of a TFT substrate in which each of a source electrode and a drain electrode includes a lower source metal layer and an upper source metal layer. The manufacturing method of the TFT substrate includes the steps of: forming an upper source metal layer by etching an upper conductive film with the first resist layer as an etching mask; forming a lower source metal layer by etching a lower conductive film; removing the first resist layer and forming a second resist layer covering the upper source metal layer; and forming a source contact portion and a drain contact portion by etching a contact layer by dry etching with the second resist layer as an etching mask.