TFT Metal Cross-Over Structure With Fewer Patterning Steps
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Solution Overview
Problem
Traditional display manufacturing processes are complex and costly, with many steps required to produce displays such as micro light-emitting diode displays, mini light-emitting diode displays, and quantum dot light-emitting diode displays, necessitating the development of more efficient manufacturing methods.
Innovation Solution
A method for manufacturing a thin-film transistor (TFT) with a metal cross over structure, involving the formation of patterned photoresists on metal layers, etching, anodizing, and depositing semiconductor layers to create a metal cross over structure that reduces the number of manufacturing steps and enhances efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional display manufacturing processes are used, then manufacturing precision and reliability are maintained, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent combines multiple manufacturing operations into integrated process steps. Specifically, the metal layer is patterned to simultaneously form the gate electrode, source electrode, and drain electrode in a single etching process, eliminating the need for separate patterning steps for each electrode. The photoresist layer is designed with varying thicknesses to enable selective etching and automatic formation of different electrode structures, merging what would traditionally require multiple discrete steps into one unified process.
Solution Approach 2:
The single metal layer serves multiple functions by being patterned into different electrode structures (gate, source, drain) simultaneously. The photoresist layer also serves multiple purposes: it acts as a masking layer for pattern transfer, and its varying thickness distribution enables selective etching to create different electrode geometries. This multi-functionality reduces the overall number of process steps and materials required, directly addressing the contradiction between manufacturing simplicity and structural complexity.
2Productivity
If the number of manufacturing steps is reduced, then productivity increases and manufacturing cost decreases, but manufacturing precision may be compromised
Solution Approach 1:
The photoresist layer is designed with non-uniform thickness distribution, where different regions have different thicknesses corresponding to different electrode patterns. The thicker regions (third photoresist layer) protect underlying metal areas that should remain as electrodes, while thinner regions (first and second photoresist layers) allow selective etching to form gate, source, and drain structures. This local variation in photoresist thickness enables precise control over electrode formation without requiring multiple patterning steps, thereby maintaining manufacturing precision while improving productivity.
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 significantly reduces manufacturing costs and enhances efficiency by minimizing the number of processing steps required for the production of TFTs with a metal cross over structure, making it suitable for the emerging display technologies.
Implementation Method 1
anodizing the etched first metal layer, in which the anodized lower metal electrode has a surface portion that is unanodized and in contact with the third mask portion
Implementation Method 2
anodizing the surface portion of the second metal layer through the second patterned photoresist until the second metal layer has an anodized segment extended from the surface portion
Data Source
AI summary
A method of manufacturing a thin-film transistor TFT with a metal cross over structure includes: etching the first metal layer through a first patterned photoresist to form a gate electrode and a lower metal pattern; anodizing the first metal layer; removing the first patterned photoresist; depositing a semiconductor layer on the etched first metal layer; depositing a second metal layer on the semiconductor layer; anodizing the second metal layer through a second patterned photoresist to form an anodized segment; and etching the second metal layer through the second patterned photoresist to form first and second upper metal patterns, in which the first upper metal pattern has drain and source electrodes connected to the anodized segment and electrically isolated from each other by the anodized segment, and the second upper metal pattern forms a metal cross over structure with the lower metal pattern.