Tantalum Source-Drain Etching for Oxide Semiconductor Stability
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Solution Overview
Problem
The manufacturing of oxide semiconductor thin-film transistors is hindered by the need for additional etch stopper layers, increasing costs and reducing yield rates, while traditional etching processes with strong acids damage the oxide semiconductor layer, leading to instability and excessive contact resistance.
Innovation Solution
A method for manufacturing a thin-film transistor substrate that omits the etch stopper layer by using a tantalum-containing second metal layer and hydrogen peroxide etchant solution for patterning, ensuring an excellent contact interface between the oxide semiconductor layer and source/drain terminals, preventing damage and crowding effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an etch stopper layer is added to protect the oxide semiconductor layer, then the stability of the transistor is improved, but the manufacturing cost increases and yield rate decreases due to additional photolithographic processes
Solution Approach 1:
The invention extracts and removes the etch stopper layer from the transistor structure, replacing it with a differently configured source/drain electrode structure that achieves protection without requiring the additional layer and associated photolithographic processes
Solution Approach 2:
The invention merges the protective function previously performed by the separate etch stopper layer into the source/drain electrode structure itself, where the source/drain electrode serves both as a functional component and as a protective element for the oxide semiconductor layer
2Ease of manufacture
If strong acid etchants are used to etch the metal source/drain electrode, then the etching process is effective, but the oxide semiconductor layer is damaged leading to deterioration and instability
Solution Approach 1:
The invention changes the chemical parameter of the etchant from strong acid to weak acid solution, which maintains sufficient etching capability for the metal source/drain electrode while being gentle enough to avoid damaging the oxide semiconductor layer
Solution Approach 2:
The invention applies different etching conditions to different regions: the weak acid selectively etches the metal source/drain electrode while preserving the oxide semiconductor layer, achieving localized differential etching based on material properties
3Device complexity
If the etch stopper layer is omitted to reduce manufacturing cost, then the manufacturing process is simplified, but the oxide semiconductor layer becomes vulnerable to damage from strong acid etchants
Solution Approach 1:
The invention converts the potential harm of acid etching into a benefit by using weak acid that selectively removes the metal source/drain electrode material while leaving the oxide semiconductor layer intact, thus achieving both simplification and protection
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 simplifies the manufacturing process, reduces costs, enhances yield rates, and achieves a high channel width/length ratio while preventing oxide semiconductor layer damage, resulting in improved quality and stability of the thin-film transistor substrate.
Implementation Method 1
applying an etchant solution containing hydrogen peroxide to carry out etching in an etching process of the source/drain terminals
Implementation Method 2
applying an etchant solution containing hydrogen peroxide to carry out etching in an etching process of the source/drain terminals... damages of the oxide semiconductor layer caused by traditional etchant solution can be prevented
Data Source
AI summary
The present invention provides a method for manufacturing a thin-film transistor substrate, which has a simple process and achieves an excellent contact interface between an oxide semiconductor layer and source/drain terminals through successive film forming so as to prevent crowding effect resulting from excessive contact resistance. Further, by using a metallic material containing tantalum to make the source/drain terminals and applying an etchant solution containing hydrogen peroxide to carry out etching in an etching process of the source/drain terminals, damages of the oxide semiconductor layer caused by traditional etchant solution can be prevented and quality of the thin-film transistor substrate can be enhanced. Further, it is not necessary to additionally form an etch stopper layer to protect the oxide semiconductor layer in the back channel so as to achieve relatively high channel width/length ratio (W/L), and also simplify the structure of the thin-film transistor substrate, simplify the manufacturing process, reduce the manufacturing cost, and enhance yield rate.