TFT Substrate Etching Uniformity via BCl3 Oxide Removal
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Solution Overview
Problem
Conventional TFT LCD manufacturing processes result in uneven etching rates due to metal oxide formation on the source/drain metal layer, leading to poor uniformity and performance issues in TFT devices.
Innovation Solution
A method involving the use of a BCl3 gas to remove metal oxides generated on the source/drain metal layer, followed by etching with a mixing gas containing Cl2 and BCl3, ensuring all etched areas are processed at a uniform rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mixing gas including Cl2 gas and BCl3 gas is used to etch the source/drain metal layer, then the etching process can be performed, but the etching rate becomes uneven due to metal oxides remaining on the surface, leading to poor uniformity of source electrode and drain electrode
Solution Approach 1:
The patent applies preliminary action by introducing a BCl3 gas treatment step before the main etching process to remove metal oxides from the source/drain metal layer surface. This preliminary removal of harmful metal oxides ensures that subsequent etching proceeds uniformly across all areas, resolving the contradiction between achieving etching and maintaining uniformity.
2Productivity
If the source/drain metal layer is formed by physical vapor deposition, then the metal layer can be deposited efficiently, but metal on the surface is prone to oxidation when contacted with air, generating metal oxides that interfere with subsequent etching
Solution Approach 1:
The patent implements preliminary action by adding a BCl3 gas treatment step immediately after deposition and before etching. This preliminary treatment removes the harmful metal oxides that form during air contact, allowing the high-efficiency physical vapor deposition process to be maintained while eliminating the subsequent etching uniformity problems.
Solution Approach 2:
The patent converts the harmful effect of metal oxidation into a beneficial process by using the BCl3 gas to react with and remove the metal oxides. The oxidation that would normally be harmful is transformed into a controlled chemical reaction that facilitates uniform etching by eliminating surface contaminants.
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 enhances the uniformity of the source and drain electrodes, thereby improving the performance of TFT devices by maintaining consistent etching rates across all areas.
Implementation Method 1
a step S401 of using a BCl3 gas to remove metal oxides generated due to contact of the source/drain metal layer with air
Implementation Method 2
a step S402 of using a mixing gas including a Cl2 gas and the BCl3 gas to etch the source/drain metal layer
Data Source
AI summary
The present disclosure provides a method for manufacturing a TFT substrate and a method for manufacturing a TFT display apparatus, including the steps of: providing a base substrate; forming a source/drain metal layer on the base substrate; depositing a photoresist layer on the source/drain metal layer and patterning the photoresist layer to form a desired pattern of the photoresist layer; using a BCl3 gas to remove metal oxides generated on surface of the source/drain metal layer with air; and using a mixing gas including a Cl2 gas and the BCl3 gas to etch the source/drain metal layer.